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y= DISCOVERY
REPORTS
Issued by the Discovery Committee, Colonial Office, London
on behalf of the Government of the Dependencies of the Falkland Islands
Vol. XIII, pp. i-vi
TITLE-PAGE AND LIST OF CONTENTS
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DISCOVERY REPORTS
VOLUME XIII
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DISCOVERY REPORTS
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PRINTED IN GREAT BRITAIN BY WALTER LEWIS, M.A., AT THE UNIVERSITY PRESS, CAMBRIDGE
ERRATUM
DISCOVERY REPORTS, VOL. XIII, 1936. FORAMINIFERA. PART IV.
ADDITIONAL RECORDS FROM THE WEDDELL SEA SECTOR.
On pp. 21 and 27 and explanation of Plate I, figs. ro and 11, for Thurammina corrugata,
" sp.n., substitute Thurammina brucei, sp.n. (after the late Dr W. S. Bruce, leader of the
Scottish National Antarctic Expedition, 1902-4).
The specific name corrugata is preoccupied by Thurammina corrugata, Earland, 1934
(Discovery Reports, Vol. x, p. 70, No. 103, Plate II, figs. 15-18). The two species are
distinct and not closely related.
CONTENTS
FORAMINIFERA. PARTIV. ADDITIONAL RECORDS FROM THE WEDDELL
SP Ato Cl ORR OME VTAGEE EAE OBA TNE DI Bye SEB SaYcunes COAT
(published 30th June, 1936)
- By Arthur Earland, F.R.M.S.
InTRopucTorY NOTE ; : : : : : ; : : : : 5 : . page 3
CHARACTERS OF THE MATERIAL RECEIVED 6
ABSENCE OF DIATOMS ; ; j 8
Paciric INFLUENCE IN THE WEDDELL SEA . 10
FossILs II
MINERALS é : 3 ‘ ‘ ‘ ; : 13
CORRECTED CONCLUSIONS TO BE DRAWN FROM THE RECORDS 14
ACKNOWLEDGMENTS . 16
List OF STATIONS EXAMINED 16
NEw SPECIES 21
SYSTEMATIC ACCOUNT 21
SUPPLEMENTARY BIBLIOGRAPHY ; : ‘ : : : : 3 : 3 : 59
REPORT ON SOME CRYSTALLINE COMPONENTS OF THE Deposits. By F. A. Bannister, M.A. and
M. H. Hey, M.A., B.Sc. 60
INDEX : . : : : : : : : : : : : . : : 70
Prates I, II, Ila. : : i : : : : ; ; : : following page 76
THE ROYAL RESEARCH SHIP ‘DISCOVERY II’ (published 18th July, 1936)
By R. A. B. Ardley, R.N.R. and N. A. Mackintosh, D.Sc.
INTRODUCTION . : ; : : : : : ; ‘ ; : : ; ‘ page 79
CONSTRUCTION AND DesIGN : 80
SPECIAL ACCOMMODATION FOR RESEARCH 92
SCIENTIFIC EQUIPMENT 98
Laporatory METHODS : : : . : : ‘ , : ; : : 104
Prates III-XIII_. , : : : : : : : : : : following page 106
A REPORT ON OCEANOGRAPHICAL INVESTIGATIONS IN THE PERU
COASTAL CURRENT (published 24th October, 1936)
By E. R. Gunther, M.A.
INTRODUCTION . : : ; : : 3 : : : E : 2 : - page 109
EQUIPMENT AND METHODS 120
WIND
vi : CONTENTS
A REPORT ON OCEANOGRAPHICAL INVESTIGATIONS IN THE PERU
COASTAL CURRENT (cont.)
CURRENT AND DRIFT OF THE SHIP
"TEMPERATURE
SALINITY ;
SEASONAL CHANGES .
COLOUR OF THE CURRENT .
LIFE IN THE CURRENT
PHOSPHATE CONTENT : j ‘
CONCLUSIONS ON THE RESULTS OBTAINED .
SUMMARY .
List OF REFERENCES .
APPENDICES
INDEX
page
Pirates XIV-XVI_. : : ; : : : : : : : : following page
RHINCALANUS GIGAS (BRADY), A COPEPOD OF THE SOUTHERN MACRO-
PLANKTON (published 4th November, 1936)
By F. D. Ommanney, Ph.D., A.R.C.S.
INTRODUCTION .
METHODS ‘
HYDROLOGY OF THE AREA .
Previous WorK ‘ ;
DISTRIBUTION OF RHINCALANUS GIGAS
Lire History .
DiscussION
GENERAL SUMMARY .
List OF LITERATURE .
Tas_es I-VI
page
125
134,
159
169
7s
175
180
189
235
241
248
273
276
,
Ae
Fee aT
AY. Sieus
| DISCOVERY.
REPORTS
Vol. XIII, pp. 1-76, plates I, II, 1a
ZL Bart
ioied by the Discovery Committee, Colonial Office, London
on behalf of the Galeninent of the Dependencies of the Falkland Islands
FORAMINIFERA
PART IV. ADDITIONAL RECORDS FROM THE
WEDDELL SEA SECTOR FROM MATERIAL
OBTAINED BY THE:S.Y: “SCOTIA:
by
Arthur Earland, F.R.M.S.
WITH A REPORT ON
SOME CRYSTALLINE COMPONENTS OF
THE WEDDELL SEA DEPOSITS
by th
F. A. Bannister, M.A. BR ane gakin: lta <)
with CHEMICAL ANALYSES by (aie ee Shoe
M. H. Hey, M.A., B.Sc. Pune 100
. Ns Cs :
CAMBRIDGE
AT THE UNIVERSITY PRESS
1936
Price twelve shillings net
[Discovery Reports. Vol. XIII, pp. 1-76, Plates I, IT, ILA, June, 1936]
FORAMINIFERA
PART EVs ADDITIONAL RECORDS FROM THE
WEDDELL SEA SECTOR FROM MATERIAL
OBTAINED BY THE S:Y: ‘SCOTIA’
By
ARTHUR EARLAND, F.R.M.S.
With a Report on
SOME CRYSTALLINE COMPONENTS OF
THE WEDDELL SEA DEPOSITS
By F. A. Bannister, M.A., with chemical analyses by M. H. Hey, M.A., B.Sc.,
Assistant Keepers in the Mineral Department of the British Museum (Natural History)
CONTENTS
FoRAMINIFERA. By ARTHUR EARLAND, F.R.M.S.
linyamyslueiORy INGE 6 “6 6 6 6 6 © 6 4 © 6 8 3 « © PULP?
Characters ofthesVlatetial Receivedia. sym) a-e) eee) n-ne 6
AlbsencexoimDiatomsag y-ceen lg iiiae eel enc Renee ecm ace nce ee 8
lezen Ibsusknvenree vim doe \Weelellisse 5 5 o 5 «0 » o «@ o © © i
Fossils (with Provisional Note by W. A. Macfadyen, M.C., Ph.D.). . 11
Minerals)"; oo) ine fe Asa ae a SS) oe oe ee, en ge eels
Corrected Conclusions to be drawn from the Records . . . . . . 14
INGROMIEGEANENS 6 o 6 56 o o 6 3 5 5 0 6 @ 6 6 o KO
(ListiofiStations 7) aie, fe Uke w ise #40 ee ee eck ce LO
INeWASPECIESsar cy oye) (aT A Cc oe Re cE ey ed too) te
Swaine Nee, 5 5 6 5 5 56 6 9 © 56 9 5 6 o o Bi
SLjolsaaiainy lploliopmslhy 5 5 Go 6 5 oo o 5 5 6 o 8 0 9
REPORT ON SOME CRYSTALLINE COMPONENTS OF THE WEDDELL SEA DeEposiTs.
By F. A. Bannister, M.A., and M. H. Hey, M.A., B.Sc. . . . . £60
INDEX ire eicrase ge Gude ate, eslaver pees! BNE Or GIG 14 pop eee O
lupus) I NINA, 5 5 ok ll cl ll «fll ER FO
FORAMINIFERA
PART IV. ADDITIONAL RECORDS FROM THE
WEDDELL SEA SECTOR FROM MATERIAL
OBTAINED BY THE S.Y¥. SCOTIA’
By Arthur Earland, F.R.M:s.
(Plate I; text-figs. 1, 2)
INTRODUCTORY NOTE
N February 1931, the R.R.S. ‘William Scoresby’ ran a line of stations, WS 542-55,
I] in the Weddell Sea between ro and 20° W, reaching 68° 53'S at St. WS 552. The
results were mainly hydrographical, but soundings were obtained at Sts. 552, 553, 555,
the Foraminifera from which were included in the Discovery Report (1934, X, pp. 1-208,
pls. i-x) on The Falklands Sector of the Antarctic (excluding South Georgia).
Apart from these scanty records, our knowledge of the bottom deposits of the Weddell
Sea rests on the material brought back by the late Dr W. S. Bruce, of the Scottish
National Antarctic Expedition in the S.Y. ‘Scotia’, 1902-4. In the course of her cruise
the ‘Scotia’ penetrated to the Coats Land coast of the Antarctic Continent in 74° o1’ S,
and made several lines of stations traversing the Weddell Sea between the meridians
10° and 45° W. A report on the nature of the deep sea deposits was made by Mr Harvey
Pirie (P. 1905, DSD), and the Foraminifera were described by the late F. G. Pearcey
(P. 1914, SNA). :
When I was preparing Part III of the Report on Discovery Foraminifera, it became a
matter of some importance to examine the new types described by Pearcey. But in
spite of inquiry pursued in all likely quarters these were not discoverable (see E, 1934,
A, p. 12), a fact which now seems even more regrettable than I then regarded it.
While making inquiry on the subject at the Royal Scottish Museum, Edinburgh,
where the Bruce collections are preserved, I learned from Dr A. C. Stephen that the
Museum still had a quantity of sounding deposits brought back by the ‘Scotia’. As my
Discovery report was already in proof nothing could then be done in the matter, but
after publication it seemed desirable if possible to reconstitute the missing types, and
with the Director’s approval, the whole of the material was placed at my disposal. It
included deposits from three stations, 118, 451, 459, which lie outside the Antarctic
convergence line. These are marked with an asterisk in the subjoined list of material
received. They have been disregarded in the preparation of the following report, which
is confined to stations within the convergence. The letter P in the list indicates a station
at which Pearcey recorded the presence of Foraminifera, but it is not known whether
he examined material from the other stations also. From the fact that the stations not
I-2
JUL 27 1936
4 ; DISCOVERY REPORTS
marked P proved the poorest and most refractory of the deposits, it seems probable that
Pearcey sampled them and did not proceed with their examination. Further details of
the material on which I worked will be found on pp. 16-21.
Deposit | q : Depth Description of deposit in
No. Bt oes) fathoms Date Station Log
pe 2 118 | Stanley | Falkland 3h 14. i. 03 | Mud
Harbour) Islands
8 226 | 64° 18'S | 23° 9’'W | 2739 | 17. ii. 03 | Glacial clay
II 280 | 68° 4o’S | 30° 18’W | asi 2. 111.03 | Glacial clay
12 reve |) (ots che {Sy aye toy WY AL 3. iii. 03 | Glacial clay
13 286 | 68° 11'S | 34° 177'W | 2488 5. iii.03 | Glacial clay
14 290 | 67° 39'S | 36°10’ W | 2500 6. iii.03 | Glacial mud
66° 40'S | 40°35’ W | 2425 | 10. ili.03 | Glacial mud
16 300 | 65° 29'S | 44° 6'W]| 2500 | 12. ili.o3 | Glacial clay
17 301 | 64° 48'S | 44°26'W | 2485 | 13. iii.o3 | Glacial mud and boulders
18 303 | 64° 24'S | 43° 18’W | 2547 | 14. iti.03 | Glacial mud
19 309 | 63° 51'S | 41°50’ W | 2550 | 16. iii.03 | Glacial clay
20 312 | 62° 56'S | 42°20’W | 1956 | 17. ili.03 | Glacial mud
lp 21 313 | 62° 10'S | 41° 20'W | 1775 | 18. iii.03 | Glacial mud or sand and boulders
P 277 | 338 | 59° 23'S | 49° 8’ W | 2180 | 28. xi. 03 | Diatom ooze and volcanic sand
28 342 | 56°54’S | 56°247W | 1946 | 30. xi. 03 | Globigerina ooze
P 30 387 | 65° 59'S | 33° 6’ W]| 2625 | 26. il. o4 | Glacial clay
31 391 | 66° 14'S | 31° 18’W | 2630 | 27. ii. 04 | Glacial clay
32 394 | 66° 43'S | 27°55’W | 2685 | 28. ii. o4 | Glacial clay
33 406 | 72° 18'S | 17°59’ W] 1131 3. iii.04 | Glacial mud
37 A416 | 71° 22'S | 18°15’W | 2370 | 17. ii1.04 | Glacial mud
38 417 | 71° 22'S | 16°34’W | 1410 | 18. iii.o4 | Glacial mud and stones
°32'S | 17° 15’W | 1221 | 1g. iii.o4 | Glacial mud and rocks
41 421 | 68° 32'S | 10° 52’W | 2487 | 22. iii.04 | Glacial clay
42 422 | 68° 32'S | 12°49’W | 2660 | 23. ili.o4 | Glacial clay
43 428 | 66°57'S | 11°13’ W | 2715 | 27. iii.o4 | Glacial clay
Wight
Ll
un
iS)
Ne)
on
Midd
Ww
Xo)
a
loo)
~I
Leal
2’W | 2764 | 30. iii.o4 | Glacial clay
R 45 438 | 56° 58'S | 10° 3'W] 2518 3. iv.04 | Diatom ooze and volcanic sand
1D 46 AV NGf | Isis Gite) || Gyro \iV || ito g. iv.o4 | Diatom ooze and rock
1D 47 451 | 48° 6’'S | 10° 6’W| 1742 | 13. iv. 04 | Pebbles and diatom to Globi-
gerina 00ze
‘pe 49 459 | 41° 30'S | 9°55’W | 1998 | 20. iv. 04 | Globigerina ooze
1 Depth in Station Log, 2} fathoms. 2 No. 268 in Pearcey’s list.
In addition to the stations marked P in the foregoing list, Pearcey recorded results
from three stations within the convergence from which I received no material:
Deposit ‘ Depth Description of deposit in
St. ) escrip p
No. Locality fathoms Date Station Log
I4A 291 67° 33'S 36° 35’ W 2500 7. ill. 03 Glacial mud and boulders
26A 337A 59° 40'S 48° 02’ W 2110 28. xi. 03 Glacial mud to diatom ooze
40 420 69° 33'S 15° 19’ W 2620 21. ili. 04 Glacial clay
The absence of material from St. 420 is particularly regrettable, as Pearcey records
that “a fair supply” was available, and that he prepared two pounds of the deposit,
including trawl washings, for examination. Of the eleven new species and varieties
INTRODUCTORY NOTE 5
which he described, no less than eight were recorded from this station, seven of them
occurring nowhere else. His three remaining types came from St. 346 on the Burdwood
Bank, outside the convergence line. As a result of this lack of material from St. 420,
the particular object which I had in view in undertaking the examination of the deposits
remains unfulfilled, hardly any of Pearcey’s types having been identified with certainty
at the other stations. Otherwise, however, large additions have been made to the faunal
list of the Weddell Sea, 229 species and varieties being listed in the following report,
including four new species, as against 138 species and varieties recorded by Pearcey
from stations within the Antarctic convergence. he discrepancy is even greater than
these numbers suggest, for included in Pearcey’s list of 138 species are the following
fifty-two species which I did not meet with in my examination of material, although a
few of them have been tentatively identified as synonyms of my records.
* Biloculina ringens (Lamarck) (see No. 3)
* Spiroloculina limbata, d’Orbigny
Mihiolina bucculenta, Brady
*Miholina bucculenta var. placentiformis, Brady
Astrorhiza crassatina, Brady
*Syringammina minuta, sp.n.
*Rhabdammina cornuta, Brady
*Rhizammina indivisa, Brady
R. algaeformis, Brady
* Sorosphaera confusa, Brady
Saccammina socialis, Brady
*Pelosina arborescens, sp.n.
*Technitella raphanus, Brady
*T. asciformis, sp.n.
*Webbinella hemisphaerica (Jones, Parker and
Brady)
*Crithionina pisum, Goés, var. hispida, Flint
*Hyperammina subnodosa, Brady
* Aschemonella ramuliformis, Brady
*Reophax adunca, Brady
*R. robustus, sp.n.
* Hormosina iregularis, sp.n.
* Haplophragmoides umbilicatum, sp.n.
*Thurammina favosa, Flint, var. reticulata, var.
nov. (see No. 30)
Trochammina turbinata (Brady) (see No. 74)
*Globotextularia anceps (Brady)
Spiroplecta biformis, Parker and Jones
*Textularia conica, d’Orbigny
*Textularia concava (Karrer)
Gaudryina pseudofiliformis, Cushman (see No.
107)
*Ehrenbergina serrata, Reuss (see No. 123)
*E. pupa (d’Orbigny)
Lagena semustriata, Williamson
*L. multicosta (Karrer)
*L. torquata, Brady
L. feildeniana, Brady
*L. acuta (Reuss)
*L. quinquelatera, Brady
*L. auriculata, Brady
*Nodosaria roemeri, Neugeboren
*N. perversa, Schwager
*Polymorphina gibba, d’Orbigny
* Uvigerina brunnensis, Karrer
*U. aculeata, d’Orbigny
Globigerina dubia, Egger (see No. 203)
Pullenia obliquiloculata, Parker and Jones
*Truncatulina dutemplei (d’Orbigny)
T. tenuimargo, Brady (see No. 210)
* Anomalina polymorpha, Costa
*Globoratalia (Pulvinulina) canariensis (d’Or-
bigny)
* Globorotalia (Pulvinulina) truncatulinoides (d’Or-
bigny)
*Fpistomina (Pulvinulina) elegans (d’Orbigny)
Nonion umbilicatulus (Montagu)
The majority of these missing species (marked with an asterisk) were recorded from
St. 420, off Coats Land, from which I had no material, or St. 342 in the Scotia Sea,
where the sample received was too small for examination. It would therefore seem that
Pearcey’s examination of the Scotia material was rather superficial. If it had been carried
through exhaustively his paper, which was the first in the Antarctic field, would have
6 : DISCOVERY REPORTS
formed a solid basis for future work, and he would have anticipated several genera and
a large number of species which have since been described from Antarctic material.
CHARACTERS OF THE MATERIAL RECEIVED
Most of the deposits received by me were in their original containers which inci-
dentally throw some light on the financial stringency of the expedition, and the
ingenuity with which Bruce adapted his resources to his work. ‘The containers were
principally bottles and jars in which provisions had been preserved, many still bearing
the original labels. Except from the two stations 313 and 417, the material consisted
only of cores from a sounding machine (? Sigsbee tube), and had originally been pre-
served in spirit. Their condition varied, some being in perfect preservation after thirty
years in store, while others, owing to defective corks, had dried up. In addition to a
sounding, each of the stations 313 and 417 also yielded a jar of washings from the trawl,
and from these the majority of the larger species have been recorded.
Every container had a label in pencil inside and a similar label in ink on the outside.
The inner label was often so embedded in the material, especially when the sample was
dry, that it was only recoverable in fragments, while the outer label was generally more
or less obliterated by dirt and wear. From a combination of the two it was, however,
possible to identify everything with certainty by means of the Station Log (B. 1918,
SLS), even when only fragments of the labels were preserved. Very few of the labels
bore the station number, but only a low serial “‘ deposit’? number, ranging between 2
(St. 118) and 49 (St. 459). But for the fact that Pearcey quotes these “‘ deposit”? num-
bers as well as the station numbers, identification would have been less certain in some
cases, as for some unknown reason Bruce did not record these “deposit”? numbers in
his Station Log. Presumably no bottom samples were preserved from the hundreds of
other stations, although the nature of the deposit is occasionally described in the log.
No shallow-water material was received from within the Antarctic convergence.
With the exception of Sts. 406, 417 and 418, which are situated on the continental slope
of Coats Land in depths of 1131-1410 fathoms, all the soundings are from the abyssal
plain of the Scotia and Weddell Seas between 1775 and 2764 fathoms. Among the
samples are a few Globigerina and diatom oozes which call for no special mention. With
these exceptions the soundings are of a character previously unknown to me, and de-
scribed by Bruce in his Station Log as “‘ Glacial Mud”’ and “Glacial Clay”’, the terms
being used without much apparent discrimination. Pirie, on the other hand, divides
these deposits into ‘“‘ Blue Mud” and ‘“‘ Blue Mud approximating to Red Clay”’. The
“Blue Mud” he regards as a terrigenous deposit extending from the Antarctic coast-line
to about 60° S, and in his chart he shows it as a uniform belt extending from Kemp
Land in 60° E to go° W in the Bellingshausen Sea. The ‘‘ Blue Mud approximating to
Red Clay”’ is shown on his chart as an elliptical area in the Biscoe and Weddell Seas to
the north of the Blue Mud belt, extending from about 40° E to nearly 40° W, and lying
between the Blue Mud and the circumpolar diatom ooze belt. The chart seems to be
more or less empirical, for the few stations from which material was obtained (Sts. 226,
CHARACTERS OF THE MATERIAL RECEIVED 7
387, 391, 394, 4324) lie in the western end of this ellipse, and the remainder of it is
probably an unknown quantity so far as bottom deposits are concerned.
As regards the foraminiferal fauna of the two deposits, there appears to be little
difference between the Blue Mud and the Blue Mud approximating to Red Clay. The
number both of species and specimens decreases enormously, as might be expected
considering the greater depth and distance from the Antarctic coast-line, but setting
aside the stations on the continental slope, where the foraminiferal fauna is abundant
and varied as it usually is on such slopes, there are many stations in the Blue Mud area
with approximately similar faunal lists to those of the stations in the area of the Blue
Mud approximating to Red Clay.
Pirie’s description of the two deposits is worth extracting, especially as he deals with
the material from a mineralogical standpoint, while any remarks of mine are necessarily
of a faunistic character.
Blue Mud. A typical specimen from the sounding tube has the following characteristics. It is of
a greenish-grey or bluish-grey colour and is a coherent, moderately tough mud with a sufficiently
clayey character to give it an unctuous feeling, but when rubbed between the finger tips one can
always feel some gritty particles. When dried it is of a light grey colour and has a slightly clayey
odour when breathed upon, and is capable of taking a lustrous polish when rubbed on the finger nail.
There is never any smell of sulphuretted hydrogen as in many terrigenous muds. Of CaCO, there is
in most cases none, but every now and again a certain amount occurs, varying from a mere trace up
to 6 per cent. This is from the shells of Foraminifera.... Siliceous organisms are extremely rare;
they may be entirely absent or there may be from a trace up to 1-2 per cent; and these are chiefly
sponge spicules and fragments of Radiolaria, very rarely diatoms.
Mineral particles over 0-05 mm. in diameter form 10-20 per cent of the deposit; the majority are
angular in shape but the larger fragments up to 2 or 3 mm. in diameter are generally sub-angular, and
occasionally glacial striae may be detected on them. Quartz grains predominate largely, but a great
variety of other minerals occurs. Glauconite is rare, being only found as casts in a few of the samples
in which there are calcareous Foraminifera. Manganese is common as a thin pellicle over other
mineral particles, and a few very small grains occur, but there are no nodules such as are found in the
abyssal Red Clays.
The remainder of the deposit is made up of ‘fine washings”. When examined microscopically
this part is found to contain occasional fragments of siliceous organisms, and a small amount of true
amorphous clayey matter, but it largely consists of minute mineral fragments under 0-05 mm. in
size, the majority being probably between 0-02 and 0-005 mm. These represent the rock flour pro-
duced by the abrasive action of the Antarctic ice-sheets ; this is carried out to sea partly in the ice of
the icebergs, but no doubt largely also suspended in the water... .’The trawl usually brought up a
large quantity of mud and rocks. The latter vary in size from fine gravel up to boulders weighing
over two cwts....Some of the rock specimens have part of their surface clear and part coated with
manganese; the shape indicates that the latter part must have been embedded in the mud, while the
former projected out into the water... . It is noteworthy that only one whale’s ear-bone was brought
up. As whales are probably quite as numerous, if not more so, in this area than in the Red Clay area
of the Pacific, the explanation can only be that they are buried by the rapidity with which this
deposit is accumulating, as contrasted with the extreme slowness of the Red Clays... .
Blue Mud approximating to Red Clay. The area. . .approaches Red Clay in many of its characters.
The colour is more of a brownish-grey than the blue or green grey of the typical Blue Mud; it is
more tenacious and clayey, and it is not so easily rubbed down for microscopic examination, but still
much more easily than a typical Pacific or Atlantic Red Clay. The mineral particles average only
about 3 per cent, of which a considerable number are of volcanic origin, but too much reliance cannot
8 : DISCOVERY REPORTS
be put on this for classification, as volcanic minerals are quite common in the Blue Muds. Ninety-
five to ninety-eight per cent of the deposit consists of ‘‘ fine washings’’, but it is the character of these
that differentiates the deposit from the true Red Clays. There is certainly a considerably larger
proportion of true clay than in the typical Blue Muds, but there is still a large amount of very minute
land-derived mineral particles—the finest rock-flour—which has probably reached its destination
largely in suspension. This area is, on the whole, about 200 fathoms deeper than the surrounding seas,
but the difference in the character of the bottom is probably mainly accounted for by the comparative
infrequency of bergs within this area, owing to the set of the currents. Here the rate of accumulation
must be slower than in the Blue Mud area, but as not a single diatom was noted in any of the
samples, one is precluded from the hypothesis that these get lost amidst the glacial detritus.
My own observations confirm most of the foregoing statements of Pirie, except that
I see little difference between the two types of deposits beyond the much lesser ‘pro-
portion of mineral particles in the ‘‘ Blue Mud approximating to Red Clay”’ samples.
The foraminiferal fauna, as already mentioned, differs only in so far as might be ex-
pected from a greater depth and distance from the Antarctic coast-line. All the Weddell
Sea soundings are very dissimilar in appearance and fauna from the Discovery deposits
obtained in the Bellingshausen and Scotia Seas, which were as a rule easily cleaned and
contained but a small percentage of clayey material. The Scotia material, on the other
hand, was so firm and coherent that many of the cores retained their form in the bottles
after thirty years in spirit, with the constant motion to which they have been subjected
at intervals. Practically none of the samples could be cleaned directly on a sieve, but
the material after slow drying generally broke down readily in hot water like a true clay,
and was then washed easily on a silk sieve of 150 meshes to the linear inch. In many
cases a second drying was necessary, and a few samples resisted even then, and were
finally broken down in hot soda solution. A fraction of the material passing through the
150-mesh sieve was washed on 200-mesh silk as a final test for the presence of Radiolaria
and diatoms. It was observed that when a sample had dried up in the bottle the layer
in contact with the glass was refractory, and could not be broken down. Presumably
some chemical reaction had been set up between the clay and the silica of the glass.
ABSENCE OF DIATOMS
The most striking distinction between the Weddell Sea material and the Discovery
deposits from the Scotia and Bellingshausen Seas was the comparative absence of
diatoms. The Discovery deposits, which were mostly from comparatively shallow water,
contained diatoms in such abundance that they clogged the meshes of the sieves. In the
Weddell Sea deposits, on the other hand, the sight of a single diatom was a noteworthy
occurrence. Pirie refers to this in the foregoing extracts from his report, and elsewhere
he remarks:
The relative amounts of diatoms in the surface waters and in the deposits form a marked contrast.
Over the whole of the Blue Mud area of the Weddell Sea diatoms are extremely abundant in the
surface waters; in the deposits on the other hand they are either entirely absent or present only in
very small quantity. ‘Their maximum occurrence on the bottom is in about 51° or 52° S (St. 447,
A.E.) where, in the surface waters, they are comparatively infrequent. Can this absence in the Blue
Mud be accounted for by the rapid accumulation of the glacial detritus hiding them? I think not—
ABSENCE OF DIATOMS 9
for a reason that is given in the paragraph dealing with the Blue Mud resembling Red Clay. It is not
a question of depth, for the difference is inconsiderable, about 2400-2700 fathoms for the Blue Mud
and 2100-2500 fathoms for the Diatom Ooze; nor can it be accounted for by the surface currents; in
the southern part of the Weddell Sea these are westerly, and in the northern part, about the boundary
of the Blue Muds and Diatom Ooze, easterly. One is thrown back on the explanation tentatively put
forward by Dr Philippi who found the same condition on the German Antarctic Expedition, viz. a
northerly undercurrent which carries off the diatoms northward. Some indication of a strong under-
current was got on the ‘Scotia’ while trawling; although this was south of 70° S lat., it may be a
widespread condition, and possibly the study of the temperatures and salinities at different depths
will throw further light on this question.
Again, referring to the diatom ooze found by the ‘Scotia’ along the meridian of
10° W, Pirie writes:
The band (of diatom ooze, A.#.) is here much wider (than the band between the Falklands and
South Orkneys, A.F.) extending from about 48°-59° S. The transition from the Blue Mud on the
southern edge is probably pretty sharp—in the Blue Mud from 61° 21’ S, 13° 2’ W (St. 4324, A.E.)
there are no diatoms; in the ooze from 56° 58'S, 10° 3’ W (St. 438, A.E.) they form 55 per cent of
the whole deposit, in 51° 7S, 9° 31’ W (St. 447, A.L.) 2103 fathoms, the percentage rises to 70.
The theory of the removal of the diatoms by a northerly undercurrent, postulated by
Philippi and accepted by Pirie, meets with the approval of Mr G. E. R. Deacon of the
Discovery staff, to whom I am indebted for much useful information. He writes as
follows :
The coldest stratum of the bottom water in the whole of the Southern Hemisphere, and in a great
part of the Northern Hemisphere, has its origin chiefly in a cold current which sinks from the
Continental Shelf in the south-west corner of the Weddell Sea. The distribution of temperature,
salinity and oxygen in the bottom waters shows very clearly that the current from this source spreads
eastwards round the whole of the Antarctic Continent, sending off northward current branches in
the Atlantic, Indian and Pacific Oceans.
Since the bottom current from the Weddell Sea spreads over such a vast area, it is reasonable to
suppose that, in the Weddell Sea itself, it will flow much more rapidly than it does elsewhere, and
the freedom of the bottom deposits from diatom ooze and light muds may be due to a greater
scouring of the bottom here than in any other region. Bruce speaks somewhere of a trawl being
carried off the bottom, although more than the customary length of warp had been paid out.
There are several entries in the Scotia’s Station Log which confirm Mr Deacon’s
statement of the force of the undercurrent. Gear was lost at several stations: at St. 416
it was “‘ doubtful if trawl reached bottom”’; at St. 418 “trawl did not touch bottom” ;
at St. 422, 2660 fathoms in 68° 32’ S, 12° 49’ W, Bruce remarks “‘ Ross Deep obliterated ;
Ross obtained 4000 fathoms, no bottom, in 68° 34’ S, 12° 49’ W””.
The chief difficulty in accepting this theory of the removal of diatoms by a northward
current appears to me to lie in the fact that a current which removed the diatoms should
also remove the clay and finer mineral particles, and deposit them to the northward. ‘The
diatoms might dissolve during their long journey, but the mineral particles should
survive. But such detritus and clay does not form any large proportion of the diatom
ooze belt in the north, where the inorganic material is described by Pirie as ‘mostly
voleanic...the probability is that these particles have been carried from the South
DXIII 2
10 DISCOVERY REPORTS
Sandwich group by the prevalent westerly winds or by floating ice”. So it seems that
for the present we must accept the facts that the surface waters of the Weddell Sea are
crowded with diatoms while very few are to be found in the bottom deposits, and leave
the explanation for future investigators.
PACIFIC INFLUENCE IN THE WEDDELL SEA
As a result of the present investigation of the Scotia material some of the conclusions
reached in the previous report (see A, pp. 12, 23-4) require modification. They were
based on the evidence of the species listed by Pearcey, which seemed to show a rather
scanty foraminiferal fauna almost entirely of a cosmopolitan cold-water description.
This still holds, so far as the western and central areas of the Weddell Sea are concerned,
as also the statement that Pearcey’s rare and new species do not extend into the Scotia-
Bellingshausen area. But the additions made to Pearcey’s list indicate that the line of
the Scotia arc can no longer be regarded as a limit to the distribution of species of
Pacific origin.
I worked out the Scotia material in order of latitude, and for a long time the results
were as expected and in accordance with Pearcey’s records. Even the rich St. 313 with
a long list of species yielded nothing unexpected. But as I got farther south I was sur-
prised to record species which had not been found at stations farther to the north and
west. At St. 286 in 2488 fathoms, almost in the centre of the southern Weddell Sea, three
species of Lagena of distinctly Pacific origin were found, L. stdebottomi (No. 172),
L. desmophora (No. 137) and L. fimbriata var. occlusa (No. 140). This station appears to
be an outlier, as no warm-water species were detected at the stations to the east or west
of it. Farther to the south, however, in the vicinity of the Coats Land coast, the evidence
becomes more striking. St. 406, the most southerly station (in 72° 18’ S), in addition to
yielding the only record of the genus Miliammina (No. 104) provided a single large
specimen of Gaudryina bradyi (No. 111), an extension of 10° S latitude on previous
records. St. 417, in 71° 22'S, yielded quite a long list of species of Pacific origin,
Lagena quadrilatera (No. 167), L. fimbriata var. occlusa (No. 140), L. lamellata (No. 155),
Cassidulina pacifica (No. 122), L. stelligera var. eccentrica (No. 176), Polymorphina
extensa (No. 197), Nodosaria raphanistrum var. (No. 185), and many other species,
including Globigerina bulloides (No. 199), not to be expected in such a high latitude.
This station represents the acme of development of warm-water species, and it is
curious that the closely adjacent stations, 416 and 418, show little evidence of Pacific
influence, which also diminishes as we go northwards away from the Antarctic coast-
line; St. 421, in 68° 32’ S, yielded several species unexpected in such latitude, but the
only distinctly Pacific forms were Lagena quadrilatera (No. 167), L. stelligera var.
eccentrica (No. 176), and L. foveolata var. paradoxa (No. 143). St. 422, in approximately
the same latitude, gave no evidence whatever of warm-water influence, nor did St. 428
(66° 57'S), St. 4324 (61° 21'S), or St. 438 (56° 58'S). The most northerly station
within the convergence, St. 447 in 51° 7’ S, gives very little indication of warm-water
influence beyond the reappearance of Globigerina bulloides (No. 199), the specimens
PACIFIC INFLUENCE IN THE WEDDELL SEA II
being smaller than those found in the vicinity of Coats Land. Passing northwards on
the same meridian of about 10° W, and outside the convergence at St. 451,' we begin to
get a typical South Atlantic Globigerina-ooze fauna, the only Pacific form noted being
Bolivina cincta, H.-A. and E. (see F 154, SG 183, A 280). ‘The most northern station
worked over was St. 4591 (41° 30’ S, 9° 55’ W), 1998 fathoms, a typical South Atlantic
Globigerina ooze which furnished a long list of species including many forms of Pacific
origin, as might be expected from a station in the path of the West Wind Drift.
The occurrence of these southern and Pacific species in the far south, near the Ant-
arctic coast-line, puzzled me greatly, and at one time I thought that all my theories of
Antarctic distribution were to be proved incorrect. It was therefore gratifying to learn
from Mr G. E. R. Deacon that there was hydrographical evidence of an inflow of
Pacific water into the Weddell Sea, in the form of a mid-water current which on reaching
the Antarctic coast-line was diverted to the west. From the records of the stations along
the meridian of 10° W, it would seem that this current must make its entry to the east
of that meridian, and its maximum influence is felt on the bottom edge of the con-
tinental shelf (St. 417). Presumably it then follows the unknown edge of the continent
into the inner extension of the Weddell Sea, an area from which no material has been
obtained, and is there lost in the cold Weddell Sea current. The outlying St. 286 may
represent a diversion of the current, but its influence is slight, and it is not to be traced
‘at the adjoining stations, 280, 282, 290 and 291, or in the line of stations 295-313,
running north-west to the South Orkney Islands.
FOSSILS
At St. 406, off the coast of Coats Land (72° 18'S, 17° 59’ W) in 1131 fathoms, and
at St. 416, farther off shore (71° 22’ S, 18° 15’ W) in 2370 fathoms, a few minute fossils
were found which are of interest as proof of the existence of ‘Tertiary strata on the ad-
jacent mainland. At St. 406 a single specimen of a calcareous alga (Dactylopora) was
found. Professor J. Pia of Vienna was good enough to examine it when working recently
at the British Museum (Natural History), and identified the specimen as Neomeris sp.,
ef. N. annulus (Parker and Jones) (Ann. Mag. Nat. Hist. (3), v, 1860, p. 474). The speci-
men differs from the type in the small size of the pores on the inner edge. Professor Pia
informed me that although an unquestionable fossil it was of no value as a zone marker,
the species having a range from Eocene to Recent in warm seas.
At the same station and also at St. 416, a little farther from the coast, a few minute
Foraminifera were found which Dr W. A. Macfadyen of Baghdad has kindly ex-
amined. He reports as follows:
1 These stations, 451 and 459, were worked out, but being outside the convergence are not included
in this report.
12 - DISCOVERY REPORTS
A PROVISIONAL NOTE ON FOSSIL FORAMINIFERA
DREDGED FROM THE WEDDELL SEA
By W. A. MACFADYEN, M.C., PuD.
Eight specimens were kindly sent to me for study, by Mr Arthur Earland. Nos. I, II and III (the
last two mounted in a transparent medium), were dredged at “‘Scotia” St. 406, 72° 18’ 5, 17° 59’ W,
in 1131 fathoms; nos. IV—VIII at St. 416, 71° 22’ S, 18° 15’ W, in 2370 fathoms.
So far as can be seen all are of essentially the same form, though there is some not inconsiderable
variation amongst them, which may be in part due to the different amounts of rolling. No. I has the
earlier part of the test missing. No. VII appears to have been partially crushed during fossilization.
Nos. I, II, IJ, VI and VII seem to be rolled and worn.
Description
The test consists of a simple, rather stout, rectilinear series of from 6 to 11 short chambers. In
cross section it is more or less circular, though the smallest specimen, No. V particularly, shows
appreciable flattening that appears to be original and not accidental. The chambers increase rapidly
in diameter from the rounded proloculus, but the final one or two are sometimes of lesser diameter than
the preceding chamber, i.e. in Nos. II, VI and VII.
The wall of the test is smoothly finished, though it is composed of small, angular quartz grains
set in little cement. This was most clearly shown in one specimen, No. VIII, that was accidentally
crushed. ‘The wall does not react visibly with dilute hydrochloric acid, so that the cement is
presumably not calcareous.
The two best preserved specimens, Nos. IV and V, show the sutures depressed, and the chambers
somewhat inflated between them, particularly in No. V. ‘The chambers are completely covered with
an ornament of vertical striations. The initial and final chambers of even these two, however, appear
to be broken.
No definite aperture is visible on any shell. Mounted in a transparent medium, no internal struc-
ture can be made out, though the tests are fairly transparent.
The specimens vary from 0-25 to 0-45 mm. inlength and from 0-11 to 0-19 mm. in greatest breadth.
Affinities
The form appears most to resemble the genus Monogenerina, Spandel (1901). Unfortunately this
genus is not adequately known, particularly as regards the material of which the test is composed.
M. texana, Cushman and Waters (1928, Journ. Palaeont., ii, p. 363, pl. xlviii, figs. 1, 2), may be
compared, though it has no ornamentation of striae, is much more compressed, and the wall is said
to be perforate.
Other genera that may also be compared are Nodosinella, Brady, and Cribrogenerina, Schubert.
As regards the external form it may be compared with such fossils as Nodosaria irwinensis, Howchin
(1895, Trans. Roy. Soc. S. Australia, xix, p. 196, pl. x, figs. 7, 8), Nodosaria striato-clavata, Spandel
(1898), Verlag des Verlags-Instituts ‘‘ General-Anzeiger”’, Niirnberg, p. 9, text-fig. 6), which has been
referred to the subgenus Spandelinoides by Cushman and Waters, 1928; and Spandelina (Spandeli-
noides) striatella, Cushman and Waters (loc. cit., p. 368, pl. xlviii, figs. 12a, 6). These three forms,
however, appear to possess calcareous tests.
Rhapidionina, Stache, is another genus externally similar, but this is a calcareous form with a
characteristic internal structure ; I am practically familiar with this genus, from the Lower Eocene of
British Somaliland, and it is clearly distinct.
Owing to the lack of essential literature in Baghdad, and my practical unfamiliarity with several
of the above genera, of which examples are not at the moment available for direct comparison, it is
difficult to carry the investigation farther at present.
FOSSILS 13
Conclusion
One tentative remark may perhaps be hazarded. The form dredged from the Weddell Sea appears
to belong amongst a group of genera, some of which are imperfectly known, which are characteristic
of rocks of a late Palaeozoic age, Carboniferous and Permian. If the above view be correct, it would
point to the interesting conclusion that strata of similar age must outcrop near by. The outcrop may
be on the sea floor, but as the two stations are at no great distance from the Antarctic coast-line it is
more likely that they have been carried to their position by ice action.
i) O01 O2 03 O4 O5mm.
! an | J
Fig. 1. Figures of ? Monogenerina sp. from the Weddell Sea,
drawn from the individual specimens.
a, side view. c, edge view.
b, oral-end view. d, aboral-end view.
At St. 312, in 1956 fathoms to the south-east of the South Orkneys, a few pyritized
diatoms and Radiolaria were observed. They resemble those to be found in the London
Clay and other Tertiary deposits, but in view of the great distance of this station from
the Antarctic coast-line, I hesitate to accept them as fossils. Recent Radiolaria are
frequent and diatoms rare at this station, so the specimens may be of recent origin,
altered by some chemical reaction.
MINERALS
Some interesting crystalline components observed in the deposits have been dealt
with by Mr F. A. Bannister and Mr M. H. Hey in a Report appended, see pp. 60 et seq.
The “envelope”’ crystals, as will be seen, are composed of hydrated calcium oxalate
and were observed at several stations besides St. 286, where they were first noticed.
14 : DISCOVERY REPORTS
I have not preserved a note of their frequency at that station, but believe they were
fairly common. At St. 226 they are abundant and variable in size up to 0-3 mm.
(300) in length of edge; some twinned and multiform specimens were also noted. At
St. 290 they are abundant but small—average length of edge probably less than o-1 mm.
(100). At Sts. 295, 300, 303 and 387 they were very rare, and of small or average
size. All the stations are in the very deep water of the Central Weddell Sea, and in
both Blue Mud and Blue Mud approximating to Red Clay areas. None were seen at
the inshore stations. It is, however, quite possible that the crystals occur elsewhere,
for owing to their size, shape and generally glassy transparency, they would be easily
overlooked among other mineral grains.
From the fact that the edges are invariably sharp and unbroken I have no doubt that
this mineral, hitherto unknown in deep sea-deposits, is formed zm sztu.
The crystals of calcium sulphate or gypsum are frequent in the residues at Sts. 387,
391 and 428, rare at Sts. 290 and 422. Sts. 387 and 391 are in Pirie’s Blue Mud ap-
proximating to Red Clay area, the others in the Blue Mud area, but all are far from land
and in great depths, 2500-2715 fathoms. The crystals are similar to those which I have
found abundantly in Gault and other fossil clays, and I have never previously seen them
in a recent deposit. It is stated by Murray and Hjort (M. and H., 1912, DO, p. 176):
From what is known of the solubility of gypsum in brines, and allowing for the excess of SO,, one
would suppose that sea-water is very nearly saturated for this salt, and that addition of, for instance,
a sulphate would precipitate it. But gypsum is unknown as a constituent of deep-sea deposits (unless
of extraneous origin), so that its solubility-limit is evidently never exceeded under submarine con-
ditions.
From the condition of the crystals, which show little signs of disintegration, the dis-
tance of these stations from the Antarctic coast-line, and the fact that I have not ob-
served any gypsum at the many stations nearer that line, it is difficult to believe that the
mineral has not been formed im sztu. The formation of the crystals may perhaps be
evidence that the deposits in the Central Weddell Sea are accumulating very slowly,
in spite of the evidence to the contrary afforded by the absence of whale’s ear-bones
noted by Pirie (see ante, p. 7).
A third crystalline component in nodular form has been identified as calcium citrate ;
it is common at St. 417, but was not observed elsewhere.
CORRECTED CONCLUSIONS TO BE DRAWN
FROM THE RECORDS
As a result of my examination of the Scotia material many of the conclusions drawn
from Pearcey’s report on the same material published in the previous report (A, pp. 10-
12, 23-5) require drastic revision. It was assumed on the basis of his lists that the for-
aminiferal fauna of the Weddell Sea was relatively scanty and of a cosmopolitan deep-
water character; that it was isolated and had little in common with the fauna found to
the west of the line of the Scotia Arc; and that there was practically no evidence of
Pacific influence in the sea.
CORRECTED CONCLUSIONS 15
It is now apparent that Pearcey’s examination of the Scotia material must have been
of a perfunctory nature. Adding to the 229 species and varieties listed in this report the
fifty-two species and varieties recorded by Pearcey which I did not find (see p. 5), and
allowing for the few cases in which our identifications may overlap as noted on p. 5,
we get a total of about 280 species and varieties within the convergence in the Weddell
Sea sector, as against 138 recorded by Pearcey. Quite a numerous and exhaustive faunal
list in itself, but taking into consideration that the minimum depth of the samples was
1131 fathoms, fairly conclusive proof that if shallow-water collections were available for
examination, the faunal list from the Weddell Sea sector would probably equal the 500
or more species and varieties recorded from the Falkland sector of the Antarctic.
The casual nature of Pearcey’s work is best shown by the fact that this report includes
over 100 species described before the publication of Pearcey’s report, and thirty-nine
which have been described by various authors since 1914, in addition to the four new
species now erected. The thirty-nine species described since the publication of his report
include seven new genera, Recurvoides, Ammomarginulina, Placopsilinella, Spiro-
locammina, Miliammina, Spiroplectammina and Delosina.
It is particularly difficult to understand how Pearcey can have overlooked some of the
large forms such as Jaculella obtusa, Hormosina carpenteri, H. ovicula, H. lapidigera,
Haplophragmoides weddellensis, H. sphaeriloculus, Cyclammina orbicularis, and C. bradyi.
Until shallow-water material from the sector becomes available it will be best to
reserve judgment as to the affinities of the Weddell Sea fauna. The present extended list
remains largely deep-water cosmopolitan, as might be expected from the great depth of
the material. But a few of the new species from the Falkland sector of the Antarctic are
found in the Weddell Sea, generally in small numbers, e.g. Thurammina protea (No. 36),
Hyperammina tubulosa (No. 41), Ammobaculites foliaceus var. recurva (No. 80), Placop-
silinella aurantiaca (No. 82), Trochammina inconspicua (No. 95), Spirolocammina tenuis
(No. 103), Spiroplectammina filiformis (No. 105), Textularia tenuissima (No. 107),
Gaudryina deformis (No. 112), Delosina wiesneri (No. 114), Nodosaria raphanistrum var.
(No. 185). It is impossible at present to say whether these originated in the Falkland
sector and have invaded the Weddell Sea, or whether they have a circumpolar distribu-
tion. As regards some of them I regard the latter explanation as probable.
The question of Pacific influence has been dealt with on p. 10. The present report
shows that there is a certain amount of such influence, distinctly traceable in a limited
area in the extreme south of the Weddell Sea, to which it appears to be almost con-
fined, but very limited as compared with that observed in the Falkland Sector.
Any general conclusions on the conditions of life in the Weddell Sea can only be
tentative in view of the limited amount of material available and the large area involved.
But it would seem that while the continental shelf and the abyssal plain at its foot con-
tain a varied and extensive fauna, and the rate of deposition of the bottom deposits is
probably much the same as elsewhere—perhaps slower than usual owing to the removal
of diatoms and much fine matter by a northerly bottom current, the central Weddell
Sea is restricted in fauna, and deposits are accumulating but slowly. If we accept the
16 ; DISCOVERY REPORTS
minerals found in this area (pp. 13-14 and et seq.) as formed 7 situ, it seems probable
that the rate of deposition must be very slow indeed.
ACKNOWLEDGMENTS
I have to thank the Director (Mr T. Rowatt) and Dr A. C. Stephen of the Royal
Scottish Museum, Edinburgh, for the opportunity of examining the Scotia material.
All types, station slides and species preparations have been deposited in that museum,
for preservation with the rest of the Bruce collections. I have also to thank Dr
S. W. Kemp, F.R.S., the Director, and Mr G. E. R. Deacon, of the Discovery staff,
for constant advice and assistance; Dr W. A. Macfadyen of Baghdad for his report
on the fossil Foraminifera; Professor J. Pia of Vienna for identification of the fossil
Alga; and Mr F. A. Bannister and Mr M. H. Hey, of the Mineral Department of the
British Museum for reporting on the minerals. Lastly, but not least, I thank the
Discovery Committee for undertaking the publication of this report.
DiS OFS LATIONS
A list of the stations within the Antarctic convergence which were worked over is
given below. The positions of the stations are shown in Fig. 2.
226. (Deposit No. 8.)
17. ii. 03. 64° 18'S, 23° 9’ W. Sounding, 2739 fathoms.
Glacial Clay. (Blue Mud approximating to Red Clay.)
About 300 cc. of tenacious blue-brown clay which was difficult to wash and was dried twice.
Only 1 cc. residue left on 150-mesh silk sieve—sand grains of all sizes, and a few Radiolaria. Pumice
and volcanic glass in the finer residues. Abundant crystals of hydrated calcium oxalate. Foraminifera
very rare, but twelve species were identified, all arenaceous except Globigerina pachyderma.
280. (Deposit No. 11.)
2. ili. 03. 68° 40’ S, 30° 18’ W. Sounding, 2511 fathoms.
Glacial Clay. (Blue Mud.)
About 150 cc. of tenacious blue clay, leaving only 1 cc. residue on 200-mesh silk sieve after
trouble in washing. Foraminifera very rare with the exception of Haplophragmoides subglobosus, and
entirely arenaceous.
282. (Deposit No. 12.)
3. ill. 03. 68° 31’ S, 32° 8’ W. Sounding, 2452 fathoms.
Glacial Clay. (Blue Mud.)
About 300 ce. of highly tenacious and slippery blue clay left only about 0-5 cc. residue on
150-mesh silk sieve. A few coarse sand grains, some fine sand and mica. Foraminifera extremely
rare, only seven species, all arenaceous.
286. (Deposit No. 13.)
5. ili. 03. 68° 11'S, 34° 17’ W. Sounding, 2488 fathoms.
Glacial Clay. (Blue Mud.)
About 150 cc. of tenacious grey clay of a very refractory nature. It was dried and washed twice,
and finally broken down with hot soda. Residue 1 cc., consisting of abundant sand grains of all sizes,
abundant Globigerina pachyderma and many small Lagenae and other calcareous Foraminifera.
1 'The nature of the deposit is that stated in the Station Log; the words in brackets indicate the area in
which the station is situated on Pirie’s chart.
LIST OF STATIONS 17
Arenaceous Foraminifera were comparatively rare. Evidence of Pacific water influence indicated by
several species, Lagena exsculpta, L. fimbriata var. occlusa, L. stelligera, L. sidebottomi, L. desmophora.
Numerous crystals of hydrated calcium oxalate were observed.
290. (Deposit No. 14.)
6. ill. 03. 67° 39'S, 36° 10’ W. Sounding, 2500 fathoms.
Glacial Mud. (Blue Mud.)
About 400 cc. of tenacious blue clay which, after drying, broke down readily, leaving very little
residue: a manganese-coated pebble, many large sand grains, fine angular sand, a few crystals of
gypsum and abundant crystals of hydrated calcium oxalate, mostly small. Sixteen species of
arenaceous Foraminifera, mostly represented by single specimens, the most interesting species being
Hippocrepina flexibilis. Sponge spicules and Radiolaria very rare; no diatoms.
“| S Sandwich
Group
10°W
Fig. 2. Positions of stations from which Foraminifera were examined.
295. (Deposit No. 15.)
IO. ili. 03. 66° 40’ S, 40° 35’ W. Sounding, 2425 fathoms.
Glacial Mud. (Blue Mud.)
About 180 ce. of tenacious slate-coloured clay was dried and washed twice, yielding as residue
a pebble coated with manganese and sessile organisms, and about 1 cc. of angular sand grains of all
sizes. Very few Radiolaria or sponge spicules, and no diatoms. Some glauconite, and a few small
crystals of hydrated calcium oxalate. Foraminifera very rare; all arenaceous.
300. (Deposit No. 16.)
12. iii. 03. 65° 29'S, 44° 6’ W. Sounding, 2500 fathoms.
Glacial Clay. (Blue Mud.) vine
About 150 ce. of tenacious blue clay which left hardly any residue on the 150-mesh silk sieve;
angular sand grains of all sizes; Radiolaria and sponge spicules very rare; no diatoms; much mica
and a few crystals of hydrated calcium oxalate ; some unrecognizable fragments of large Foraminifera.
The smaller species were scanty, worn and broken. Cyclammina pusilla was the only form occurring
with any frequency; most of the others were represented by single specimens. Of the ten species
listed, three were calcareous; viz. Lagena globosa var. setosa, Globigerina pachyderma and Eponides
bradyi.
D XIII 3
18 DISCOVERY REPORTS
301. (Deposit No. 17.)
13. lil. 03. 64° 48'S, 44° 26’ W. Sounding, 2485 fathoms.
Glacial Mud and Boulders. (Blue Mud.)
About 150 cc. of tenacious dark blue mud, drying grey, was washed twice and yielded very little
residue of sand grains of all sizes up to } in. No diatoms and hardly any Radiolaria or sponge spicules.
A few Foraminifera in the coarser material, but practically none in the fine; entirely arenaceous
except for a single specimen of Globorotalia crassa.
303. (Deposit No. 18.)
14. lii. 03. 64° 24'S, 43° 18’ W. Sounding, 2547 fathoms.
Glacial Mud. (Blue Mud.)
About 300 cc. of tenacious grey mud leaving very little residue; sand grains of all sizes; many
Radiolaria and a few sponge spicules, but no diatoms. Crystals of hydrated calcium oxalate very rare,
only one or two seen. Foraminifera very rare but more varied than usual. The twenty-six species
recorded include representatives of the three principal groups, and several interesting forms. ‘Two
species of Miliolina, M. circularis and M. venusta, represent the imperforate, and a single specimen
of Cassidulina laevigata the hyaline Foraminifera; all the others have agglutinate tests.
309. (Deposit No. 19.)
16. iil. 03. 63° 51'S, 41° 50’ W. Sounding, 2550 fathoms.
Glacial Clay. (Blue Mud.)
About 300 cc. of very tenacious blue grey clay left only 2 cc. residue on the 150-mesh silk sieve ;
two small pebbles without sessile organisms and fine sand; many Radiolaria and sponge spicules;
about six diatoms seen. Foraminifera, except Haplophragmoides subglobosus, almost absent. Five
arenaceous species in all were listed.
312. (Deposit No. 20.)
17. lll. 03. 62° 56'S, 42° 20’ W. Sounding, 1956 fathoms.
Glacial Mud. (Blue Mud.)
About 300 cc. of tenacious blue clay drying in hard lumps which broke down readily, nearly all
passing through the 150-mesh silk sieve. Residue a few large sand grains and fragmentary large
Foraminifera; many Radiolaria and sponge spicules and fine sand, both quartz and flint. Occasional
diatoms, but extremely uncommon. Foraminifera rare but varied, including Spiroplectammina
filiformis, Ammomarginulina ensis, Textularia tenuissima and Spirolocammina tenuis. A few of the
Radiolaria and diatoms were pyritized—possibly fossils.
313. (Deposit No. 21.)
18. ill. 03. 62° 10'S, 41° 20’ W. Sounding and trawl, 1775 fathoms.
Glacial Mud or sand and boulders over 2 cwt. (Blue Mud.)
Three samples were received:
A. Sounding: about 350cc. of hard lumps of dry blue mud which broke down readily. Residue
pebbles and angular sand grains of all sizes; organisms of any kind except Radiolaria very rare; a
few Foraminifera of many species; Radiolaria plentiful, sponge spicules not uncommon, and diatoms
very rare.
B. A tube of sand—evidently washings from A.
C. About 300 ce. of coarse material labelled ‘‘Siftings from Trawl”. Coarse sand with little
mud. Arenaceous Foraminifera abundant, especially Hormosina globulifera, Psammosphaera fusca,
Haplophragmoides weddellensis, H. subglobosus and Reophax nodulosus. Porcellanous and hyaline
forms very scantily represented. No less than eight species of Thurammina were found at this station.
338. (Deposit No. 27.)
28. xi. 03. 59° 23’ S, 49° 8’ W. (In the Scotia Sea.) Sounding, 2180 fathoms.
Diatom Ooze and Volcanic Sand. (Diatom Ooze.)
LIST OF STATIONS 19
A small tube of very refractory pale-grey mud. Residue aggregates of fine sand, Radiolaria and
diatoms (Coscinodiscus) bound together with filamentous diatoms. Sponge spicules and Foraminifera
almost entirely absent.
342. (Deposit No. 28.)
30. x1. 03. 56° 54’ S, 56° 24’ W. (In the Scotia Sea.) Sounding, 1946 fathoms.
Globigerina Ooze. (Globigerina Ooze.)
Only a few cc. of hard and refractory ooze. Residue of mud aggregates, Globigerinae and fine
sand.
This station was not worked out, the amount of material being insufficient.
387. (Deposit No. 30.)
26. i1. 04. 65° 59'S, 33° 6’ W. Sounding, 2625 fathoms.
Glacial Clay. (Blue Mud approximating to Red Clay.)
About 300 cc. of very tenacious blue-grey clay. Refractory—it was dried twice and finally
broke down with hot soda. Only 1 cc. residue left on the 150-mesh silk sieve, consisting of angular
sand grains of all sizes and many small crystals of gypsum. Foraminifera almost absent, only five
arenaceous species being listed. Radiolaria and sponge spicules very rare. No diatoms seen. Crystals
of hydrated calcium oxalate present in very small numbers. The finest residue consisted of refractory
clay aggregates.
391. (Deposit No. 31.)
27. 11. 04. 66° 14'S, 31° 18’ W. Sounding, 2630 fathoms.
Glacial Clay. (Blue Mud approximating to Red Clay.)
About 200 cc. of tenacious grey clay which left only 1 cc. residue on the 150-mesh silk sieve.
Sand grains of all sizes, some Radiolaria, a few sponge spicules and fragments of three species of
arenaceous Foraminifera. Crystals of gypsum frequent but small.
394. (Deposit No. 32.)
28. 11.04. 66° 43'S, 27° 55’ W. Sounding, 2685 fathoms.
Glacial Clay. (Blue Mud approximating to Red Clay.)
About 150 cc. of highly refractory slate-blue clay showing signs of lamination. After protracted
treatment it was at last broken down and yielded about 3 cc. of residue, flakes of clay, a few sand
grains and Radiolaria. No diatoms or sponge spicules. Foraminifera almost absent, four arenaceous
species only listed.
406. (Deposit No. 33.)
3. ili. 04. 72° 18'S, 17° 59’ W. Sounding, 1131 fathoms.
Glacial Mud. (Blue Mud.)
About 300 cc. of dark slate-coloured mud, granular and laminated, giving a residue of angular
sand grains of all sizes, mostly very small but ranging up to { in. in diameter. Many sponge spicules
and large and small Radiolaria; a few small diatoms were found in the residue retained on the
200-mesh silk sieve. Foraminifera very rare, but over 20 species were listed, including some small
specimens of Miliammina arenacea, the only record of the genus in the Weddell Sea.
A few minute fossils were obtained from this sounding which are more fully referred to on p. 11.
416. (Deposit No. 37.)
17. iii. 04. 71° 22'S, 18° 15’ W. Sounding, 2370 fathoms.
Glacial Mud. (Blue Mud.)
About 300 cc. of dark slate-blue clay with sand left a residue of 35 cc. fine angular sand with
much glauconite. Hardly any Radiolaria or sponge spicules, and no diatoms. ‘The residue was floated
with carbon-tetrachloride, but without results other than four specimens of Haplophragmoides
subglobosus, three of Cyclammina pusilla and single specimens, more or less fragmentary, of three
other species. A few minute fossils were found (see p. 11).
3-2
20 DISCOVERY REPORTS
417. (Deposit No. 38.)
18. ili. 04. 71° 22'S, 16° 34’ W. Sounding and trawl, 1410 fathoms.
Glacial Mud and Stones. (Blue Mud.) Bruce records that the trawl gave a rich haul with about
60 species.
‘Two samples were received:
A. Sounding: about 150 cc. of grey mud in hard dry lumps which were refractory and did not
disintegrate readily. It was dried again and treated with soda. Residue Globigerinae and fine sand.
Very few Radiolaria or sponge spicules and no diatoms. Globigerina spp. formed quite 98 per cent
of organisms, the remainder furnished a long list of interesting species including many Lagenae, but
the number of specimens was generally small. No Globorotaliae were observed.
B. A small jar of trawl debris, sponge fragments, coarse sand and abundant large arenaceous
Foraminifera. ‘This material was unfortunately in bad condition and was cleaned with difficulty. The
spirit had evaporated and the whole was matted together with fungoid mycelium. Some nodular
crystals of calcium citrate were common.
The foraminiferal fauna of this station shows considerable evidence of Pacific water influence.
418. (Deposit No. 39.)
1g. lll. 04. 71° 32'S, 17° 15’ W. Sounding, 1221 fathoms.
Glacial Mud and Rocks. (Blue Mud.)
About 200 cc. of tenacious blue clay, difficult to wash. Nearly all passed through the 150-mesh
sieve. Residue a few large sand grains, mud aggregates and fine sand. Foraminifera, except Globi-
gerina spp. very scanty, but varied in species. Very few sponge spicules or Radiolaria, and still
fewer diatoms which were extremely rare.
421. (Deposit No. 41.)
22. 111.04. 68° 32'S, 10° 52’ W. Sounding, 2487 fathoms.
Glacial Clay. (Blue Mud.)
About 200 cc. of tenacious clay, which was washed twice, gave a residue including some sand
grains and pebbles up to } in. diameter, coated with manganese, also angular sand grains of all sizes.
No diatoms and very few Radiolaria or sponge spicules. Very few Foraminifera in coarser residue, but
the finer sand when floated with carbon-tetrachloride gave abundant Globigerina spp. and a long list
of other forms, many of great interest and some of distinctly Pacific origin.
422. (Deposit No. 42.)
23. ill. 04. 68° 32'S, 12° 49’ W. Sounding, 2660 fathoms.!
Glacial Clay. (Blue Mud.)
About 300 cc. of tenacious clay yielded as coarse residue a few small manganese-coated pebbles
with Tolypammina vagans sessile on them; the fine residue consisted of refractory clay aggregates,
sand grains, numerous Radiolaria and a few small crystals of gypsum. No diatoms and very few
sponge spicules. Foraminifera other than Globigerina pachyderma very rare.
428. (Deposit No. 43.)
27. 11. 04. 66° 57'S, 11° 13’ W. Sounding, 2715 fathoms.
Glacial Clay. (Blue Mud.)
About 300 ce. of very tenacious and slippery clay, extremely refractory. Washed three times it
gave very little residue on the 150-mesh silk sieve. A few large sand grains with sessile Tolypammina
vagans; clay aggregates, many Radiolaria, frequent crystals of gypsum (small); very few sponge
spicules and an occasional diatom. Foraminifera very rare and entirely arenaceous.
432A. (Deposit No. 44.)
30. ll. 04. 61° 21’ S, 13° 2’ W. Sounding, 2764 fathoms.
Glacial Clay. (Blue Mud approximating to Red Clay.)
About 150 ce. of blue clay, laminated and very refractory. It was washed three times and finally
* Note in log: “ Ross Deep obliterated. Ross obtained 4000 fathoms, no bottom, in 68° 34’ S, 12° 49’ W.”
LIST OF STATIONS 21
with hot soda. Residue, clay aggregates of all sizes, some sand grains, a few Radiolaria and diatoms,
practically no sponge spicules. Foraminifera, except Glomospira charoides, practically absent, five
other species only recorded, fragmentary or single specimens.
438. (Deposit No. 45.)
3. 1V. 04. 56° 58'S, 10° 3’ W. Sounding, 2518 fathoms.
Diatom Ooze and Volcanic Sand. (Diatom Ooze.)
About 75 cc. of muddy lumps in fine mud which washed easily. Coarse residue, scoriae and
pumice with a few large Foraminifera. Fine residue, Radiolaria, and fine volcanic sand with abundant
diatoms but in less proportion than the sand. Foraminifera extremely rare; sixteen species in
all, including Spzrolocammina tenuis.
447. (Deposit No. 46.)
g. iv. 04. 51° 7S, 9° 31’ W. Sounding, 2103 fathoms.
Diatom Ooze and Rock. (Diatom Ooze.)
About 150 cc. of pale grey ooze, dry and in lumps; very hard to break down, the ooze being
matted together with filamentous diatoms which felted in the sieves. Foraminifera varied; a long
list, including several species of Pacific origin, but none present in any numbers except Globigerina
Spp.
List OF NEW SPECIES
Thurammina corrugata Trochammina soldani
Haplophragmoides weddellensis Eponides weddellensis
Yo EMATIC ACCOUNT
Note. To economize space no synonyms are given for species which have been
described in the three previous reports. For purposes of reference the numbers given
in the earlier reports, on the Falklands, South Georgia and Antarctic, are printed in
brackets after the specific name, e.g. 2. Pyrgo murrhyna (Schwager) (F 3) (SG 1)
(A 2). Those species recorded by Pearcey within the Antarctic convergence are noted,
together with the numbers of the stations at which they were obtained.
Order FORAMINIFERA
Family MILIOLIDAE
Subfamily MJLIOLININAE
Genus Pyrgo, Defrance, 1824
1. Pyrgo depressa (d’Orbigny) (F 2) (A 1).
One station: 417.
Only three specimens in all, one being very large.
Pearcey: 342, 420, 447 ‘‘sparingly at all”’.
2. Pyrgo murrhyna (Schwager) (F 3) (SG 1) (A 2).
One station: 417.
‘Two specimens only.
eaneeyi3A2) Taney.
22 ; DISCOVERY REPORTS
3. Pyrgo vespertilio (Schlumberger) (F 104) (SG 4) (A 6).
One station: 417.
One large specimen only.
Pearcey (? as Biloculina ringens (Lamarck)): 420 “rare”’.
Genus Miliolina, Williamson, 1858
4. Miliolina oblonga (Montagu) (F 15) (SG 14) (A 14).
One station: 406.
A single small but typical specimen.
5. Miliolina pygmaea (Reuss) (F 25) (SG 18) (A 19).
Two stations: 406, 447.
Extremely rare and small.
6. Miliolina venusta (Karrer) (F 26) (SG 19) (A 20).
Three stations: 303, 417, 421.
Extremely rare and small, except at St. 417, where two medium-sized specimens
were found.
Pearcey: 447 ‘‘few”’.
7. Miliolina tricarinata (d’Orbigny) (F 28) (SG 20) (A 22).
One station: 418.
One small but typical specimen.
8. Miliolina circularis (Bornemann) (F 29) (SG 21) (A 23).
Three stations: 303, 313, 417.
Very rare; a few large specimens at Sts. 313, 417; one small example at St. 303.
Pearcey: 420 “‘a few specimens”’. He notes that the calcareous shells show no sign of
pauperation in spite of the great depth (2620 fathoms). My specimens agree with his in
this respect.
g. Miliolina labiosa (d’Orbigny) (F 34) (A 26).
Two stations: 438, 447.
Extremely rare, small and thin-walled at both stations.
Genus Sigmoilina, Schlumberger, 1887
10. Sigmoilina obesa, Heron-Allen and Earland (F 38) (SG 22) (A 28) (Plate I,
figs. 2-4).
‘Two stations: 313, 417.
Very rare, but typical and very large. This is an extension of 10° latitude to the south
of previous records.
SYSTEMATIC ACCOUNT 23
11. Sigmoilina tenuis (Czjzek) (F 40) (SG 23) (A 30).
One station: 417.
A single large and complanate specimen (see A 30).
Pearcey: as Spiroloculina tenuis, but only outside the convergence.
12. Sigmoilina sigmoidea (Brady) (A 31).
‘Two stations: 417, 421.
Rare; the specimens, though typical, are small at St. 417, and very small at St. 421.
Subfamily KERAMOSPHAERINAE
Genus Keramosphaera, Brady, 1882
13. Keramosphaera murrayi, Brady (Plate I, figs. 7-9).
Keramosphaera murray, Brady, 1882, K, pp. 242-5, pl. xiii, figs. 1-4; 1884, FC, pp. 224-7,
text-figs. 8 a-d on p. 225.
K. murrayt, Pearcey, 1914, SNA, p. 996.
K, murrayt, Wiesner, 1931, FDSE, p. 111, pl. xvii, figs. 199-200.
Two stations: 313, 417.
A single perfect specimen, and a fragment showing the internal structure, were found
at St. 313; also a single fairly good specimen at St. 417, which had evidently been built
into the wall of a worm tube or other organism. They are all undersized and probably
young individuals.
The perfect specimen from St. 313 is 1-5 mm. in diameter as compared with 2-5 mm.,
the size given by Brady for the type. The specimen from St. 417 is approximately the
same size. Pearcey does not record the size of the Scotia specimen. Of Wiesner’s two
specimens, judging by the photographs, one is slightly larger than the type, the other
rather smaller. They were obtained at Gauss St. 83, 3410 m., “sandy glacial mud”’
(O55 05,°S,.80: 19’ EB):
Pearcey: ‘‘ A perfect specimen among the material from St. 420, 2620 fathoms, in the
Weddell Sea, outside the diatomaceous zone, in a terrigenous deposit of glacial mud
containing but a trace of carbonate of lime.” He also records the information that three
additional specimens had been found in material from the original Challenger Station
157 (53° 55'S, 108°35’E, 1950 fathoms), subsequent to the publication of the
Challenger report, making in all five Challenger specimens. ‘There should therefore
now be in existence eleven specimens:
Five from the ‘ Challenger’.
One from the ‘Scotia’ (Pearcey), whereabouts unknown.
Three from the ‘Scotia’ (A.E.) in Royal Scottish Museum, Edinburgh.
Two from the ‘Gauss’, presumably in the Zoological Museum of the University of
Berlin with the other Gauss specimens.
The known range of Keramosphaera now extends from 41° 20’ W (Scotia St. 313) to
108° 35’ E (Challenger St. 157) between latitudes 53° 55’ S (Challenger) and 71° 22’S
(Scotia St. 417), an enormous area at present little known. Though unquestionably a
rare form, I think it is likely to be found whenever suitable material is obtained from
24 : DISCOVERY REPORTS
this area, although it does not figure in the list of species found by F, Chapman and
W. J. Parr in the material collected by the Mawson Expedition between 60°-70°S
and go°-150° E, or from this Expedition’s deep-water Stations between Australia and
the Antarctic. It is possible that the species may be found in greater numbers in
shallower water nearer the Antarctic coast-line, which would seem a more natural
habitat for such a large porcellanous species. As no specimen has ever been found in
the Pacific or western area of the Antarctic, the species is probably peculiar to the
eastern area between Graham Land and the Kerguelen plateau.
Until more material is available the real structure of the organism must remain
speculative, but after a careful examination of my specimens I am inclined to the belief
that the structure is not so complex as Brady thought. He regarded the sphere of
Keramosphaera as analogous to the disc of Orbitolites in structure, but to me the structure
seems quite different. If a specimen of Keramosphaera is examined by direct light
while immersed in fluid, it shows the chambers filled with air. ‘They present the ap-
pearance of unseptate tubes wandering irregularly in all directions, dividing and joining
again and passing over and under one another. There is no definite septation visible
in the tubes but a slight constriction at intervals, and especially at the point of division.
The tubes open on the surface in numerous low arched apertures (Plate I, fig. 9) with
slightly thickened lip. These layers of tubules are concentric, for the test when it
breaks shows a tendency to separate at the layers, as shown in Hollick’s fig. 2 (B. 1882,
K, pl. xiii, fig. 2), and in one of my specimens from St. 313. Examination of a
fractured surface of the section photographed by Wiesner or even the section figured
by Hollick (fig. 3, wt supra), seems to confirm this tubular structure rather than the
layers of chamberlets postulated by Brady. If this suggested tubular structure is borne
out by further research, the subfamily Keramosphaerinae would probably be found
to be nearer akin to the Nubecularinae than to the Alveolininae.
Keramosphaera is not easily illustrated, and I think the admirable photographs of
Wiesner are more truthful than the original drawings of Hollick. They bring out the
characteristic blistered surface texture, and show the apertures.
Family ASTRORHIZIDAE
Subfamily ASTRORHIZINAE
Genus Astrorhiza, Sandahl, 1857
14. Astrorhiza arenaria, Norman.
Astrorhiza limicola, M. Sars, 1868 (non A. limicola, Sandahl), LUHD, p. 248; G. O. Sars, 1871,
HF, p. 252.
A. arenaria, Norman, 1876, V, p. 213.
A. arenaria, Brady, 1879, etc., RRC, 1879, p. 43; 1882, FKE, p. 711; 1884, FC, p. 232, pl. xix,
figs. 5—10.
A. arenaria, Pearcey, 1914, SNA, p. 997.
One station: 432A.
Only a fragment, probably referable to this species.
Pearcey: 291, 420 (apparently many, A.E.).
SYSTEMATIC ACCOUNT 25
Genus Vanhoeffenella, Rhumbler, 1905
15. Wanhoeffenella gaussi, Rhumbler (SG 38) (A 51) (Plate I, fig. 5).
One station: 313.
A single specimen from 1775 fathoms, a notable extension of depth.
Genus Pelosina, Brady, 1879
16. Pelosina cylindrica, Brady (A 56) (Plate I, fig. 1).
One station: 417.
A single large specimen, 20 mm. in length, was found in the trawl washings from
St. 417, on the continental slope off Coats Land. It has many specimens of Hyper-
ammina friabilis and other species built into the wall of the test.
Pearcey: 313, 417, 420 “sparingly”.
Genus Crithionina, Goés, 1894
17. Crithionina granum, Goés (F 54) (SG 46) (A 61).
One station: 290.
One small specimen.
18. Crithionina mamilla, Goés (F 55) (SG 47) (A 62).
One station: 313.
A single good specimen.
Subfamily PILULININAE
Genus Bathysiphon, M. Sars. 1872
19. Bathysiphon filiformis, G. O. Sars (A 70).
Eight stations: 226, 387, 394, 416, 421, 422, 438, 447.
Fragments only, sometimes not uncommon. The best and largest were found at
Sts. 438, 447, 2518-2103 fathoms, diatom ooze. Judging by its absence from the trawl
washings from Sts. 313, 417, the species does not favour a bottom of glacial clay or mud.
Pearcey: 301, 418, 420 “‘nowhere abundant”’. He refers to the fact that the outer
layer of the test contains mineral particles of a larger size than is usually the case. ‘This
characteristic is seen in specimens from several of my stations, but not universally.
20. Bathysiphon argillaceus, Earland (A 75).
One station: 313.
Only a single specimen.
Subfamily SACCAMMININAE
Genus Sorosphaera, Brady, 1879
21. Sorosphaera depressa, Heron-Allen and Earland (SG 55) (A 77).
One station: 417.
A single-chambered detached specimen, probably referable to this species.
DXIIl
26 DISCOVERY REPORTS
Genus Psammosphaera, F. E. Schulze, 1875
22. Psammosphaera fusca, Schulze (F 60) (SG 56) (A 79).
Nineteen stations: 226, 280, 282, 286, 290, 295, 301, 303, 309, 312, 313, 338, 416, 417, 418, 422,
428, 4324, 447.
Universally distributed but uncommon at most stations. Frequent in the soundings
from Sts. 290, 303 and 312 and abundant in the trawl washings from Sts. 313, 417.
As usual the species exhibits great variation. The most generally distributed is the
roughly constructed form figured in F (pl. viii, figs. 3, 4), which attains a large size in the
trawl washings. The typical sphere of Schulze, in which the sand grains are of approxi-
mately equal size, is comparatively rare, but represented the species at Sts. 286, 338,
and was observed in moderate numbers with the rough type at Sts. 313, 417, 422.
Sessile and double specimens were frequent in the trawl washings, and were observed
at several other stations.
Pearcey: 286, 313, 3374, 342, 416, 417, 418, 420 “‘larger and more abundant on
glacial deposits than in the Globigerina oozes’’—I agree.
23. Psammosphaera parva, Flint (SG 57) (A 81).
‘Two stations: 406, 422.
A single specimen at each station.
Genus Saccammina, M. Sars, 1868
24. Saccammina sphaerica, M. Sars (SG 60) (A 83).
One station: 417.
Small roughly constructed specimens, without produced neck and having merely a
simple aperture, are not uncommon in the trawl washings from St. 417. They are not
easily distinguishable from Psammosphaera fusca except by their larger size. This may
have caused them to be overlooked at other stations.
In a small tube of various specimens picked out from the trawl on the ship were a few
gigantic individuals, mostly typical, of smooth construction and with produced neck.
In the same tube were others of similar rough construction to those referred to above.
Pearcey : 291, 301, 313, 417, 420 “in considerable numbers, of large size and typical”.
Genus Proteonina, Williamson, 1858
25. Proteonina difflugiformis (Brady) (F 61) (SG 62) (A 85).
Nine stations: 226, 286, 290, 295, 301, 303, 312, 417, 428.
Common at St. 303, rare or very rare elsewhere. Except at St. 312, where two large
coarsely constructed specimens were found which might be primordials of Reophax sp.,
all the examples are of a small, neatly constructed, flask-shaped form.
Pearcey : 300, 3374, 338, 342, 387, 447 ‘‘it was not found at any of the stations south
of the circle”.
SYSTEMATIC ACCOUNT 27
26. Proteonina tubulata (Rhumbler) (SG 64) (A 86) (Plate I, fig. 6).
Two stations: 303, 422.
Three excellent specimens at St. 303, and one at St. 422.
Genus Tholosina, Rhumbler, 1895
27. Tholosina bulla (Brady) (F 65) (SG 67) (A 94).
Two stations: 313, 438.
One good specimen at St. 313; represented only by “‘scars”’ on sand grains at St. 438.
Pearcey: 420 “‘several specimens attached to Rhabdammina, etc.”
28. Tholosina vesicularis (Brady) (F 67) (SG 69) (A 97).
One station: 313.
A single specimen.
Genus Thurammina, Brady, 1879
29. Thurammina papillata, Brady (SG 72) (A gg).
Three stations: 280, 313, 417.
Single specimens at Sts. 280, 417; many large individuals at St. 313, presenting great
contrast in the relative proportions of sand and cement, some being quite smooth and
formed almost entirely of cement, while others are roughly sandy.
Pearcey: 291, 420 “‘rarely”’.
30. Thurammina corrugata, sp.n. (Plate I, figs. 10, 11).
‘Two stations: 313, 417.
A young individual at St. 313; fragments of one or more large specimens at St. 417.
Test approximately spherical, darkly ferruginous in colour; wall composed of very
minute sand grains and ferruginous cement, extremely thin and crinkled all over, the
inner surface duplicating the exterior—what are raised ridges exteriorly are depressed
troughs interiorly, and vice versa. Apertures minute but numerous, scarcely produced
above the surface of the external corrugations, rarely distinguishable on the inner side.
They are more conspicuous but fewer in the young shell. ‘Test very fragile in the dry
condition, but probably flexible in life.
T. corrugata is, I think, unique in its genus in its wall characters. It is so uniformly
thin that the external corrugations are exactly duplicated internally. The cavity of
Thurammina is normally smooth, except for slight pits corresponding to the external
apertures, even in such strongly decorated species as 7. favosa.
I was at first inclined to associate my specimens with Thurammina favosa, var.
reticulata, Pearcey (SNA, p. 1003, pl. i, figs. 11, 12), found by him “in moderate num-
bers” at St. 420. Pearcey’s description is vague, the first paragraph would describe any
form of 7. papillata. In the second paragraph he describes the exterior as “ marked by
an irregular network of raised ridges which easily distinguish this form from the type
T. favosa, Flint; the ridges are robust and irregular, of a much lighter colour than that
4-2
28 ; DISCOVERY REPORTS
of the wall generally”. Except as regards colour this part of the description might
be held to apply to my specimens. But Pearcey makes no reference to ridges on the
internal surface in his description, while his rather poor drawings indicate a smooth
interior.
The young individual from St. 313 is about 0-35 mm. indiameter. The larger fragments
from St. 417 are estimated to have formed a sphere 1-o mm. in diameter.
31. Thurammina castanea, Heron-Allen and Earland (F 614) (A 100).
One station: 313.
A large but broken specimen.
32. Thurammina haeusleri, Heron-Allen and Earland (SG 73) (A 101).
One station: 313.
‘Two specimens only, one being very large.
33. Thurammina favosa, Flint (Plate I, fig. 14).
Thurammina favosa, Flint, 1899, RFA, p. 278, pl. xxi, fig. 2.
T. papillata var. favosa, Heron-Allen and Earland, 1912, etc., NSG, 1917, p. 549, pl. xxviii,
fig. 17.
Two stations: 313, 417.
A single large specimen at each station; that from St. 313 is attached to a large sand
grain, but retains its spherical shape.
34. Thurammina albicans, Brady (SG 75) (A 102).
One station: 313.
Three good specimens were found.
Pearcey: 342 “two specimens”’.
35. Thurammina cariosa, Flint (A 105) (Plate I, figs. 12, 13).
One station: 313.
Four specimens, two being large and typical ; the others double shells similar to those
from the North Sea figured in H.-A. and E., 1912, etc., NSG, 1917, p. 550, pl. xxix,
fig. 6.
36. Thurammina protea, Earland (SG 76) (A 108).
One station: 313.
One typical specimen sessile in a broken Psammosphaera.
Subfamily RHABDAMMININAE
Genus Jaculella, Brady, 1879
37. Jaculella obtusa, Brady (F 70) (SG 78) (A 111).
Two stations: 313, 417.
Good specimens are not uncommon in the trawl washings from these stations.
SYSTEMATIC ACCOUNT 29
Genus Hippocrepina, Parker, 1870
38. Hippocrepina flexibilis (Wiesner) (SG 81) (A 113).
One station: 290.
Two good specimens.
Genus Hyperammina, Brady, 1878
Note. Fragments, not specifically identifiable, but probably referable to this genus,
were observed at many stations, notably Sts. 295, 391, 406, 417. They have been dis-
regarded.
39. Hyperammina friabilis, Brady (F 71) (A 1154).
‘Two stations: 313, 417.
Rare, but good specimens in the trawl washings.
Pearcey: 420 ‘‘a few typical specimens in a more or less fragmentary condition, but
with the proloculum perfect”’.
40. Hyperammina elongata, Brady (F 72) (SG 85) (A 116).
Two stations: 313, 417.
Rare, but good specimens in the trawl washings.
” ing
Pearcey: 291 ‘“‘few’’, 313 “rare’’, “‘walls built of coarser material than is seen in
typical specimens”’. My specimens agree.
40a. Hyperammina laevigata, J. Wright (F 73) (SG 86) (A 117).
One station: 313.
One good specimen and a fragment.
41. Hyperammina tubulosa, Earland (A 120).
One station: 295.
Two fragments which appear to be referable to this species.
Genus Saccorhiza, Eimer and Fickert, 1899
42. Saccorhiza ramosa (Brady) (F 56a) (SG 89) (A 122).
Four stations: 303, 312, 313, 417.
Fragments are common at these four stations, largely built of spicules at St. 312, of
sand with occasional spicules elsewhere.
Pearcey: 291, 313, 3374, 342, 417, 420 ‘‘nowhere numerous”.
Genus Marsipella, Norman, 1878
43. Marsipella cylindrica, Brady (F 78) (SG g2) (A 125).
Two stations: 313, 447.
Fragments built of spicules are not uncommon at St. 313; rare, and built of sand, at
St. 447.
Pearcey: 342 (frequency not stated).
30 DISCOVERY REPORTS
Genus Rhabdammina, M. Sars, 1869
44. Rhabdammina abyssorum, M. Sars (F 79) (A 126).
Three stations: 313, 417, 418.
One small three-rayed specimen at St. 313; fragments, probably referable to this
species, occurred rarely at the other stations.
Pearcey: 313, 3374, 417 “three-rayed form...more abundant at 337A than at the
other two”’.
45. Rhabdammina discreta, Brady (F 80) (SG 93) (A 127).
‘Two stations: 313, 438.
A few poor specimens at St. 313; only one at St. 438.
Pearcey: 420 “‘fine well-developed specimens. ..in plenty”.
46. Rhabdammina linearis, Brady (A 128).
Two stations: 313, 417.
Many good specimens at each station.
Genus Aschemonella, Brady, 1879
47. Aschemonella catenata (Norman).
Astrorhiza catenata, Norman, 1876, V, p. 213.
A. catenata, Brady, 1879, etc., RRC, 1879, p. 42, pl. iv, figs. 12, 13.
Aschemonella scabra, Brady, 1879, etc., RRC, 1879, p. 44, pl. iil, figs. 6, 7.
A. catenata, Brady, 1884, FC, p. 271, pl. xxvii, figs. 1-11; pl. xxviia, figs. 1-3.
A. catenata, Pearcey, 1914, SNA, p. 1005.
Two stations: 312, 417.
Many fragments: large at St. 417, off Coats Land, smaller at St. 312 in the western
Weddell Sea.
Pearcey: 420 “‘a few specimens”’.
Family LITUOLIDAE
Subfamily LITUOLINAE
Genus Reophax, Montfort, 1808
48. Reophax scorpiurus, Montfort (F 82) (SG 95) (A 133).
Four stations: 312, 313, 338, 428.
Frequent but small at Sts. 312, 338; rare elsewhere.
Pearcey : 342 “sparingly”’.
49. Reophax curtus, Cushman (A 134).
Two stations: 290, 313.
Rare at St. 313; one specimen at St. 290.
SYSTEMATIC ACCOUNT 31
50. Reophax pilulifer, Brady (F 82a) (SG 97) (A 137).
One station: 417.
Only a single small specimen. The rarity of this species compared with its frequency
in Discovery material (A 137) is no doubt due to the greater depth of the Scotia
soundings.
Pearcey: 291, 301, 313, 420 ‘‘not common”.
51. Reophax fusiformis (Williamson) (F 83) (SG gg) (A 138).
One station: 290.
A single small specimen.
52. Reophax dentaliniformis, Brady (F 84) (SG ror) (A 140).
One station: 313.
Very small and rare. The greater depth is probably responsible for the scarcity of a
species so abundant in Discovery material (A 140).
Pearcey: 313, 447 “rare but typical’’.
53. Reophax spiculifer, Brady (SG 100) (A 141).
Three stations: 312, 406, 418.
Occasional fragments at each station.
54. Reophax longiscatiformis, Chapman (A 142).
‘Two stations: 313, 417.
Several fragments at St. 313; one only at St. 417.
55. Reophax micaceus, Earland (A 143).
One station: 303.
A single typical specimen.
56. Reophax nodulosus, Brady (F 84a) (SG 103) (A 145).
Eighteen stations: 226, 282, 286, 290, 295, 300, 301, 303, 313, 387, 391, 406, 417, 418, 421, 422,
428, 438.
One of the most typical species of the Weddell Sea deposits, found in more or less
abundance in nearly all the soundings, generally in a fragmentary condition. Most of
the fragments were of small specimens, probably not exceeding 3-4 mm. in length. In
the trawl washings from St. 313 perfect specimens up to 5 mm. in length were frequent,
they were regular and neatly constructed. At St. 417 the species reaches a gigantic size,
the largest fragment was 16 mm. in length, and if perfect the specimen would have
exceeded 25 mm. These large individuals are probably very old, they are coarsely con-
structed of large sand grains, and the chambers are elongate with constricted sutures.
Pearcey : 301, 313, 416, 417, 418, 420, 447. He notes the abundance and large size of
the specimens at St. 417 “several measuring more than one inch in length”’.
32 DISCOVERY REPORTS
57. Reophax distans, Brady (SG 104) (A 148).
Three stations: 312, 313, 438.
Large, very coarsely constructed fragments are not uncommon in the trawl washings
from St. 313. Single neatly built fragments elsewhere.
Genus Nodellum, Rhumbler, 1913
58. Nodellum membranaceum (Brady) (A 153).
‘Two stations: 438, 447.
Extremely rare: a good specimen at St. 447.
Rearceye 313)» rake.
Genus Hormosina, Brady, 1879
59. Hormosina globulifera, Brady (F 89) (SG 108) (A 154).
Nine stations: 290, 301, 303, 312, 313, 417, 428, 432A, 447.
Common at St. 313, and frequent at St. 417 in the trawl washings; also frequent in
the soundings from Sts. 303 and 447; rare or very rare elsewhere. The majority of the
specimens everywhere are megalospheric, rarely exceeding two chambers, but micro-
spheric specimens up to 4-5 chambers were found at Sts. 303, 313, 417, exceptionally
large at the last station. The tests are usually constructed of coarse sand and roughly
finished, but of fine sand and cement, neatly finished at Sts. 428, 447.
Pearcey: 295, 420 “‘rare”’.
60. Hormosina normani, Brady (Plate I, fig. 19).
Hormosina normani, Brady, 1879, etc., RRC, 1881, p. 52; 1884, FC, p. 329, pl. xxxix, figs. 19-23.
H. normani, Pearcey, 1914, SNA, p. 1007.
H. normani, Wiesner, 1931, FDSE, p. 92, pl. x, figs. 119-21.
One station: 417.
Rare, but attaining a gigantic size and up to four chambers. These rapidly increase in
diameter, and are neatly constructed, the walls being very thin. The largest specimen,
fragmentary, had a final chamber nearly 5 mm. in diameter. It is probable that the
species is widely distributed in the Weddell Sea, as fragments believed to be the
apertural disc between successive chambers were seen in several soundings, the thin
globular tests having become disintegrated.
Pearcey: 291 “not uncommon”’, 313 “‘rare”’, 417 “‘in fair abundance and of very
large size”.
61. Hormosina carpenteri, Brady.
Moniliform Lituola, Carpenter, 1875, M, 5th ed., p. 531, fig. f; 1881, 6th ed., p. 563, fig. f.
Hormosina carpenteri, Brady, 1879, etc., RRC, 1881, p. 51; 1884, FC, p. 327, pl. xxxix, figs.
Fou bcae 313, 417, 418, 421.
Fragments only, never exceeding two chambers, usually constructed of coarse sand,
but at St. 313 of fine sand and cement as in the North Atlantic type.
SYSTEMATIC ACCOUNT 33
62. Hormosina ovicula, Brady (A 155).
Two stations: 313, 447.
Rare fragments at each station. None of the specimens can have attained the size of
those recorded from shallower water in the Palmer Archipelago (A 155).
63. Hormosina ovicula var. gracilis, Earland (SG 105) (A 156).
One station: 447.
Many single chambers of this fragile organism were found.
64. Hormosina lapidigera, Rhumbler (A 157).
Two stations: 313, 417.
Occasional specimens were found in the trawl washings.
Genus Haplophragmoides, Cushman, 1910
65. Haplophragmoides canariensis (d’Orbigny) (F go) (SG 109) (A 158).
One station: 417.
A few rather small specimens at St. 417, off Coats Land.
ReaLcey: 337,A0 rare.
66. Haplophragmoides weddellensis, sp.n. (Plate I, figs. 15-16).
Thirteen stations: 226, 282, 290, 295, 301, 303, 309, 313, 387, 394, 417, 418, 422.
Test massive and rough, nautiloid but not quite symmetrical, consisting of two or
more convolutions with 5-6 chambers in the last convolution. Umbilical regions more
or less depressed, one more so than the other. Constructed of sand grains, very large in
proportion to the size of the test, firmly imbedded in ferruginous cement and projecting
so as to give a very rough exterior. Aperture small and loop-like on the inner face of
the final chamber.
Greatest breadth up to 2-0 mm. Thickness at final chamber about 1:2 mm.
Common in the trawl washings from Sts. 313 and 417: more or less rare at the re-
maining stations. It would appear that the size of the sand grains employed increases
with advancing age; small and young individuals are less roughly constructed and use a
larger proportion of cement. In large specimens the sand grains often project like rocks
from the surface.
Most of the specimens which I succeeded in laying open had a large primordial
chamber, but the microspheric form occurs at St. 309 and occasionally elsewhere. It is
more neatly constructed and the sunken umbilici expose several convolutions of small
chambers.
H. weddellensis belongs to the group of H. canariensis and is most nearly allied to
H. crassimargo (Norman). But it differs, not only from that species but from all others of
the genus, in its extremely coarse and irregular construction.
I cannot think how Pearcey can have failed to notice this form which is so abundant
in the trawl washings. He describes and figures a new species H. umbilicatum, which
5
D XIII
34 7 DISCOVERY REPORTS
bears a general resemblance to H. weddellensis but differs in the number of chambers to
the convolution, and is not so coarsely constructed, so far as can be judged by his figure.
H. umbilicatum is reported as occurring “in abundance” at St. 420, but nowhere else.
In the absence of his types, and of material from St. 420, I have not associated his
species with the widely distributed form, but further research may prove the identity
of the two species and reduce H. weddellensis to a synonym of H. umbilicatus. Altern-
atively Pearcey’s species may prove to be the microspheric form of H. weddellensis (his
figure suggests microspheric growth), which would also give his name priority.
67. Haplophragmoides sphaeriloculus, Cushman (F 93) (SG 111) (A 161) (Plate I,
figs. 17, 18).
Eight stations: 303, 312, 313, 406, 417, 422, 428, 438.
Large specimens are not uncommon at St. 417, and single large specimens were also
found at Sts. 312 (the only example), and 313 (species rare). Elsewhere all specimens
were small; frequent at Sts. 303 and 428; rare or very rare at the other stations.
68. Haplophragmoides trullissatus (Brady) (A 162).
Six stations: 226, 282, 290, 300, 301, 313.
Rare at Sts. 301, 313, where both megalospheric and microspheric individuals were
found. Very rare elsewhere.
Pearcey : 300, 3374, 416, 420 “rare”. (See also No. 102.)
69. Haplophragmoides scitulus (Brady) (F 94) (SG 112) (A 163).
Four stations: 282, 416, 417, 422.
A single specimen at each station; that at St. 422 was built into the wall of Psammo-
sphaera.
Pearcey: 291, 313, 416, 417 “‘rare’’. His records probably included the form since
separated as Recurvoides contortus (No. 74).
70. Haplophragmoides nitidus (Goés) (A 165).
Two stations: 313, 417.
Two specimens at St. 313; frequent and typical at St. 417.
71. Haplophragmoides subglobosus (G. O. Sars) (F 95) (SG 113) (A 166).
Twenty-four stations: 226, 280, 282, 286, 290, 295, 300, 301, 303, 309, 312, 313, 387, 391, 394,
406, 416, 417, 418, 421, 422, 428, 432A, 447.
Recorded from every station within the convergence which was examined except
Sts. 338 and 438, this is by far the most common and widely distributed species in
the Weddell Sea, and is more or less common everywhere.
Two distinct forms occur, nearly always together, though often in varying proportions.
One is very roughly built of large sand grains which project from the test; the other is
smoothly constructed of smaller grains with more cement, and the exterior is neatly
finished. ‘The coarse form is generally larger than the smooth. At Sts. 406 and 418 only
the smooth form occurs, and reaches the same size as the coarse form at other stations.
SYSTEMATIC ACCOUNT 35
At Sts. 312, 313 and 417 the smooth form attains a large size, and the normal aperture
is subdivided by bridges across the slit, as is often the case with large apertured species.
It is the Cribrostomoides bradyi of Cushman, but I am convinced from a long study of
the species in the Haplophragmium oozes of the Cold Area of the Faroe Channel that it
is only an advanced stage of growth of H. subglobosus.
Pearcey’s records are not easily understood. Of the type he says that it occurs at
Sts. 300, 313, 416, 417, 418, 420, 447, ““but nowhere common”. He records Cribro-
stomoides bradyi, Cushman, separately as “‘rare”’ at Sts. 313, 418, 420.
72. Haplophragmoides glomeratus (Brady) (SG 114) (A 167).
Six stations: 226, 301, 303, 312, 313, 417.
Frequent at St. 417; rarer at Sts. 312, 313 where the specimens were large; very rare
elsewhere.
Pearcey: 420 “‘rare”’.
73. Haplophragmoides rotulatus (Brady) (SG 115) (A 168).
Four stations: 312, 313, 406, 417.
Very rare, except at St. 406 where the specimens are rather more numerous, smaller
and less coarsely constructed than at the other stations. None of them can be regarded
as quite typical.
Pearcey: 3374 ‘few’, 342 ‘“‘rare”’.
Genus Recurvoides, Earland, 1934
74. Recurvoides contortus, Earland (A 169) (Plate I, figs. 20-22).
Eight stations: 300, 301, 303, 313, 394, 406, 417, 421.
Rare everywhere except at Sts. 406, 417 where the species is not uncommon and a
good series was obtained; less frequent at St. 313. These three stations are in shallower
water (1131-1775 fathoms) than the others, which all lie near the 2500 fathom line.
Pearcey’s records of Haplophragmoides scitulus (No. 69) probably included this
species. He also records Trochammina turbinata (Brady) at Sts. 300, 447 “rare”. ‘This
is hardly likely to have been Brady’s species (see A, p. 91) but may have been Recurvoides
contortus.
Genus Ammobaculites, Cushman, 1910
75. Ammobaculites agglutinans (d’Orbigny) (F 96) (SG 116) (A 170) (Plate I, figs.
22n2A).
Five stations: 303, 309, 313, 406, 417.
Large specimens are frequent in the trawl washings from Sts. 313, 417; single smaller
individuals in the soundings from the other stations. As a rule specimens have only 2-3
chambers in the extended series, but typical many-chambered examples occur at
Sta sis
Pearcey : 3374, 338, 342, 447 “nowhere very abundantly”.
36 : DISCOVERY REPORTS
76. Ammobaculites agglutinans var. filiformis, Earland (SG 116) (A 171).
Four stations: 280, 286, 303, 417.
A single specimen at each station.
77. Ammobaculites americanus, Cushman (F 97) (SG 117) (A 172).
Two stations: 312, 313.
Very rare: two specimens at St. 312, and a single small individual at St. 313.
Pearcey: 342 ‘‘rare”’.
78. Ammobaculites tenuimargo (Brady) (SG 120) (A 173).
Two stations: 312, 313.
Only two specimens from the sounding at St. 312; common and large in the trawl
washings from St. 313.
Pearcey: 3135420) ‘Tare
79. Ammobaculites foliaceus (Brady) (SG 121) (A 174).
Three stations: 312, 313, 417.
Very rare everywhere, the best specimens at St. 312. Those from St. 417 were very
small.
80. Ammobaculites foliaceus var. recurva, Earland (A 175).
Four stations: 303, 312, 313, 428.
Several typical specimens at St. 312; single typical individuals elsewhere.
Genus Ammomarginulina, Wiesner, 1931
81. Ammomarginulina ensis, Wiesner (SG 122) (A 176).
Three stations: 312, 313, 417.
Frequent and exhibiting great variation in the extent of the uncoiling of the chambers
at St. 313; rarer at St. 312; a few small and pauperate specimens at St. 417, off Coats
Land.
Genus Placopsilinella, Earland, 1934
82. Placopsilinella aurantiaca, Earland (A 178).
‘Two stations: 313, 417.
Not uncommon on sand grains at both stations, but easily overlooked. The chambers
are smaller and darker than the type, resembling the North Atlantic specimens referred
to in A 178.
Subfamily TROCHAMMININAE
Genus Ammolagena, Eimer and Fickert, 1899
83. Ammolagena clavata (Jones and Parker) (F 99) (SG 124) (A 179).
Three stations: 290, 313, 417.
A single small specimen from the sounding at St. 290; frequent in the trawl washings
from Sts. 313 and 417.
Pearcey: 291 “common”’, 313, 342, 420 ‘‘rare’”’.
SYSTEMATIC ACCOUNT 37
Genus Tolypammina, Rhumbler, 1895
84. Tolypammina vagans (Brady) (F 100) (SG 125) (A 180).
‘Two stations: 422, 428.
A few specimens sessile on pebbles or large sand grains at each station.
Pearcey: 291, 417, 420 “fine typical specimens of a dark greyish-brown colour”’.
Genus Ammodiscus, Reuss, 1861
85. Ammodiscus incertus (d’Orbigny) (F 1o1) (SG 126) (A 181).
Three stations: 226, 301, 312.
Only a single very small specimen at each station. Its rarity is rather curious as the
species is so universally distributed.
Pearcey : 337A ‘‘sparingly’”’.
Genus Glomospira, Rzehak, 1885
86. Glomospira gordialis (Jones and Parker) (F 102) (SG 127) (A 183).
Five stations: 226, 290, 295, 303, 422.
Very rare everywhere. Free growing individuals at Sts. 303 and 422; both free and
sessile at St. 295; sessile only at Sts. 226 and 290.
Pearcey: 342 “sparingly”.
87. Glomospira charoides (Jones and Parker) (F 103) (SG 128) (A 184).
Twelve stations: 286, 290, 295, 300, 301, 303, 312, 313, 417, 428, 4324, 438.
Fairly frequent considering the poverty of the material at Sts. 312, 428 and 4324; at
the last station ten small specimens were found, more than the number of specimens of
all the other species present. Never more than two specimens at the remaining stations,
all very small except two of normal size at St. 313. This is evidently one of the essential
species of the glacial muds and clays.
Pearcey : 342, 416, 447 “not in any abundance”’.
Genus Trochammina, Parker and Jones, 1860
88. Trochammina squamata, Jones and Parker (F 104) (SG 131) (A 188).
‘Two stations: 295, 417.
A single specimen at St. 295; large, typical and frequent at St. 417, where one sessile
individual was also found.
89. Trochammina inflata (Montagu) (F 108) (SG 134) (A 191).
‘Two stations: 303, 417.
A single specimen at each station.
go. Trochammina malovensis, Heron-Allen and Earland (F 109) (SG 135) (A 192).
Five stations: 286, 312, 313, 338, 406.
Extremely rare everywhere.
38 = DISCOVERY REPORTS
gi. Trochammina nana (Brady) (F 110) (SG 136) (A 193).
Three stations: 312, 313, 417.
Frequent at St. 313; rare at St. 417; a single specimen at St. 312.
Pearcey: 3374 rate
92. Trochammina soldanii, sp.n. (Plate I, figs. 32-34).
Three stations: 226, 290, 303.
Test free, rotaloid, inequilateral ; spire depressed but visible on the dorsal side which
is slightly umbilicate, the ventral side, exhibiting only the last convolution, being very
deeply umbilicate. Consisting of about four convolutions, each of seven chambers. The
two earlier convolutions are constructed of chitin and fine cement and the chambering
is very distinct; the two later convolutions are increasingly coarse in structure and it is
difficult to distinguish the chambers; the last convolution often contains large sand
grains out of proportion to the rest of the test. Peripheral edge rounded; aperture very
small on ventral side, near the junction of the final chamber with the preceding con-
volution.
Width up to 1-3 mm. Thickness at the final chamber 0-9 mm. Very rare, only an
occasional specimen at each station. The species is very distinctive, isomorphous to
some extent with Rotalia soldani, d’Orbigny. Its nearest relative is probably T. rossensis,
Warthin (W. 1934, FRS, p. 3, text-figs. 1-3), from the Bay of Whales, Ross Sea, 280 fms.,
from which it differs in its larger size, more deeply depressed ventral umbilicus and
greater number of chambers.
93. Trochammina bradyi, Robertson (F 111) (SG 137) (A 196).
Three stations: 312, 417, 438.
A single large typical specimen at each station. Its rarity as compared with the
Discovery records is remarkable. None of the malformed variety referred to in A 196
was observed.
94. Trochammina globigeriniformis (Parker and Jones) (F 110A) (SG 140) (A 197).
Five stations: 301, 313, 406, 417, 428.
Not uncommon at Sts. 313 and 417; very rare elsewhere. All the specimens are small.
Pearcey : 313, 3374, 342, 417, 447 ‘“‘nowhere common”.
95. Trochammina inconspicua, Earland (SG 139) (A 199).
Eight stations: 226, 300, 312, 313, 338, 406, 417, 428.
Not infrequent at Sts. 300 and 417; very rare elsewhere.
Pearcey’s records of T. globigeriniformis may perhaps include specimens of this allied
species.
Genus Ammosphaeroidina, Cushman, 1910
g6. Ammosphaeroidina sphaeroidiniformis (Brady) (SG 142) (A 206).
Two stations: 313, 428.
A large specimen at St. 313, and two smaller at St. 428.
SYSTEMATIC ACCOUNT 39
Genus Cystammina, Neumayr, 1889
97. Cystammina pauciloculata (Brady) (SG 144) (A 208).
One station: 447.
A single specimen.
Pearcey (as Ammochilostoma (Trochammina) pauciloculata): 447 “a few specimens”’.
Subfamily LOFTUSINAE
Genus Cyclammina, Brady, 1876
g8. Cyclammina cancellata, Brady (F 114) (SG 147) (A 211).
Four stations: 280, 303, 418, 421.
Frequent at St. 421, both megalospheric and microspheric; single specimens only at
the other stations. Nearly all are more or less abraded, and it is possible that the speci-
mens may have been carried by ice from shallower water, as the species is not usually
found in great depths. Some of the specimens at St. 421 are coated with a thin black
layer of manganese, evidence that the shells have been dead for a long time.
Pearcey: 420, 447 “‘rarely”’.
99. Cyclammina contorta, Pearcey (Plate I, figs. 29-31).
Cyclammina contorta, Pearcey, 1914, SNA, p. 1009, pl. ii, figs. 5~7.
One station: 438.
Three specimens in more or less perfect condition, which I refer tentatively to
Pearcey’s species, though in the absence of his types identification is uncertain.
The specimens agree better with Pearcey’s figure than with his description, in which
he states that the last two convolutions completely envelop the others. The figures on
the other hand show only one external convolution, and in this respect agree with my
specimens.
I doubt whether C. contorta is anything more than a local form of C. cancellata. The
colour scheme to which he draws attention is not a reliable diagnostic feature; the
“suture lines, very dark, almost black” occur in one of my specimens, but not in the
others, and may be due to a coating of manganese, as in some of my specimens of
C. cancellata from St. 421.
Pearcey: 417, 420 “‘not abundant”.
100. Cyclammina orbicularis, Brady (SG 148) (A 212) (Plate I, figs. 27, 28).
Five stations: 313, 406, 417, 418, 432A.
Common in the soundings from Sts. 406, 418 and in the trawl washings from St. 417,
all of which are near the coast of Coats Land. Rare in the soundings from Sts. 313
and 432A which are far out in the Weddell Sea.
It is inexplicable how Pearcey can have overlooked this large species.
1o1. Cyclammina pusilla, Brady (A 213) (Plate I, figs. 25, 26).
Fourteen stations: 280, 282, 286, 290, 295, 300, 301, 303, 312, 313, 406, 416, 417, 418.
Common in the soundings at Sts. 282, 290, 295, 301, 312; frequent in soundings at
40 DISCOVERY REPORTS
Sts. 280, 286, 300, 416, 418 and in the trawl washings at Sts. 313 and 417; rare else-
where.
This is one of the most characteristic and widely distributed species of the Weddell
Sea, and is more abundant in the deep water clays, where few species flourish, than near
the Antarctic coast-line. Specimens vary greatly in size, the large microspheric form
occurring with unusual frequency and sometimes predominating to the exclusion of the
smaller megalospheric form. The number of chambers varies greatly between 10 and
the typical 15 described by Brady.
Pearcey : 300, 313, 338, 416, 417, 420, 447 ‘‘but nowhere common ”’.
102. Cyclammina bradyi, Cushman (A 214).
Nine stations: 290, 303, 309, 312, 313, 387, 417, 422, 428.
Occurs with variable frequency, but never common. The best and largest specimens
in the trawl washings from Sts. 313 and 417; at the other stations specimens were rather
under normal size. Both megalospheric and microspheric forms were noted at St. 309.
As recorded in A 214, specimens often incorporate sand grains in the usual cement.
Pearcey does not record the species as such, but it is possibly included in his records
of Haplophragmoides trullissatus (Brady) (No. 68), Cushman’s species having been
erected on one of Brady’s figures of Trochammina trullissata.
Subfamily SILICININAE
Genus Spirolocammina, Earland, 1934
103. Spirolocammina tenuis, Earland (A 215) (Plate I, figs. 35-37).
Two stations: 312, 438.
Frequent at St. 312, to the south-east of the South Orkneys, and not very far from
St. WS 199, the principal locality for the types; here 13 specimens were found, in all
stages of growth. Only two specimens at St. 438, which is far to the north-east on the
eastern edge of the Weddell Sea. Both stations are in very deep water, 1956-2518
fathoms, approximately the same depth as the original types from the Scotia and
Bellingshausen Seas, 3264-4517 metres.
The sigmoiline curve is quite pronounced in young individuals, but becomes flattened
out in large adult tests.
Genus Miliammina, Heron-Allen and Earland, 1930
104. Miliammina arenacea (Chapman) (SG, pp. go, 92) (A 216) (Plate I, figs. 38-40).
One station: 406.
‘Twelve specimens in all were found at St. 406, the nearest inshore station off Coats
Land, 1131 fathoms. They are all much below the average size, and only the largest
have the specific characters sufficiently developed to be identified with certainty. The
young individuals (as mentioned in A 216) are not specifically identifiable, but in the
absence of adult specimens of the other species are almost certainly M. arenacea. All
the specimens are nearly white in colour.
SYSTEMATIC ACCOUNT 41
The discovery of Miliammina in the extreme south of the Weddell Sea is a note-
worthy extension of the range of the genus, and my comments on the subject in the
previous report (A, pp. 11, 24) require modification. The species may be found larger
and better developed whenever material from shallower water in the Weddell Sea be-
comes available for examination. In any case the present discovery closes part of the
long gap in the circumpolar records and, but for its absence from the records of the
German South Polar expedition, the genus might be included among those having a
circumpolar distribution. Such may eventually prove to be the case.
Family TEXTULARIIDAE
Subfamily SPIROPLECTAMMININAE
Genus Spiroplectammina, Cushman, 1927
105. Spiroplectammina filiformis, Earland (A 224).
Three stations: 280, 303, 312.
Single specimens at Sts. 280 and 303; four examples at St. 312. They are all typical
as regards form, but not so deeply ferruginous as the type, the colour varying between
light grey and brown. All the stations are in the central area of the Weddell Sea in very
deep water, 1956-2547 fathoms.
Subfamily TEXTULARIINAE
Genus Textularia, Defrance, 1824
106. Textularia catenata, Cushman (A 228).
Four stations: 417, 421, 438, 447.
Very rare at St. 438; frequent to common at the other stations.
107. Textularia tenuissima, Earland (SG 156) (A 229)
Seven stations: 303, 312, 313, 338, 406, 417, 447.
Common at Sts. 312 and 313; frequent at St. 417; more or less rare elsewhere.
The specimens are characteristic everywhere but vary greatly in size: small at St. 312,
very large at St. 417, large at most other stations.
Pearcey’s only records of Textularia within the convergence are 7’. conica, d’Orbigny
and T. concava (Karrer) from St. 342 in the Scotia Sea. I have not seen either of these
species. It is difficult to understand how he can have overlooked the genus in the
Weddell Sea material. He records Gaudryina pseudofiliformis, Cushman, at Sts. 313 and
338, and in the previous report (A, p. 11) I suggested that this record might refer to
Gaudryina apicularis, Cushman, which had been found in the deep water of the Scotia
Sea. Having met with neither of these species of Gaudryina in the Weddell Sea, I am
now inclined to the opinion that Pearcey’s record may refer to Tewxtularia tenuissima,
which occurs at both stations mentioned by him.
DXII +
42 : ; DISCOVERY REPORTS
108. Textularia antarctica, Wiesner (A 232).
One station: 417.
Only a few specimens at St. 417, off Coats Land, in 1410 fathoms. Its absence else-
where is probably associated with the great depth of the deposits.
Subfamily VERNEUILININAE
Genus Verneuilina, d’Orbigny, 1840
109g. Verneuilina bradyi, Cushman (SG 160) (A 234).
Three stations: 313, 406, 447.
Frequent at Sts. 406 and 447; a single large specimen at St. 313.
Pearcey: 342 “sparingly”.
110. Verneuilina bradyi var. nitens, Wiesner (A 235).
Six stations: 286, 313, 417, 421, 422, 447.
Common at St. 421; rare or very rare elsewhere.
Genus Gaudryina, d’Orbigny, 1839
111. Gaudryina bradyi, Cushman (SG 161) (A 241).
One station: 406.
This species is represented by a single large specimen at St. 406, off Coats Land.
Pearcey: 342 in the Scotia Sea (56° 54'S), which he claims as a southern record.
St. 406 (72° 18’ S) considerably extends its range.
112. Gaudryina deformis, Earland (SG 163) (A 242).
One station: 417.
Not uncommon. Some of the specimens are even more irregular in growth than the
types.
Genus Clavulina, d’Orbigny, 1826
113. Clavulina communis, d’Orbigny (SG ~65) (A 247).
Eight stations: 312, 313, 338, 406, 417, 418, 438, 447.
Fairly frequent at all the stations, both megalospheric and microspheric forms being
usually present. Except at St. 438, where the diatom ooze contains a large proportion
of volcanic sand, and the few specimens are very dark, they have the characteristic
Antarctic texture (see SG 165, A 247). At St. 447 a few of the specimens show a ten-
dency to incorporate larger sand grains in the test.
Pearcey: 313 “‘rare”’, 337A “few”, 342 “rare”, 417, 418 “rare”.
Family BULIMINIDAE
Subfamily BULIMININAE
Genus Delosina, Wiesner, 1931
114. Delosina wiesneri, Earland (A 266).
One station: 447.
SYSTEMATIC ACCOUNT 43
A single good megalospheric specimen identical with the Discovery examples. The
record is of great interest in linking up the known areas of distribution, which now
extend from St. WS 482 in 57° 16’ 30” W to the Gauss St. 56 in 89° 38’ E. It also
marks a great extension of depth, Scotia St. 447 being in 2103 fathoms on diatom ooze,
the previous maximum being 385 m. at the Gauss station.
Genus Virgulina, d’Orbigny, 1826
115. Virgulina schreibersiana, Czjzek (F 138) (SG 174) (A 269).
Six stations: 286, 312, 417, 418, 421, 447.
Frequent or common except at Sts. 312 and 447 where it is very rare. The specimens
are usually large, especially at St. 417.
Pearcey: 417, 418 “nowhere abundant”’.
116. Virgulina bradyi, Cushman (F 141) (SG 176) (A 268).
One station: 447.
A single small specimen only from this station, just inside the convergence. Its
rarity is remarkable.
Genus Bolivina, d’Orbigny, 1839
117. Bolivina punctata, d’Orbigny (F 143) (SG 177) (A 272).
One station: 418.
A single very small and pauperate specimen. The noticeable absence of this species
in the Weddell Sea is probably accounted for by the great depth at most stations.
Subfamily CASSIDULININAE
Genus Cassidulina, d’Orbigny, 1826
118. Cassidulina laevigata, d’Orbigny (F 157) (SG 185) (A 283).
Three stations: 303, 417, 418.
Single specimens only at Sts. 303 and 417; rare at St. 418; they are all in deep water,
1131-2547 fathoms.
11g. Cassidulina crassa, d’Orbigny (F 160) (SG 188) (A 286).
Four stations: 286, 417, 421, 447.
Never very common and all small at Sts. 286 and 421. Some very large specimens as
well as small at Sts. 417 and 447.
120. Cassidulina crassa var. porrecta, Heron-Allen and Earland (F 161) (A 287).
One station: 447.
A single large specimen from 2103 fathoms, just inside the convergence.
121. Cassidulina subglobosa, Brady (F 162) (SG 189) (A 288).
Six stations: 286, 338, 417, 418, 421, 447.
Small specimens are frequent or common at Sts. 286, 418 and 421 and rare at Sts.
0-2
44 DISCOVERY REPORTS
338 and 417. Very large, thick-walled specimens are frequent at St. 447, just inside
the convergence.
Pearcey: 286, 313, 342, 417, 447 ‘‘not common at any of them”’.
122. Cassidulina pacifica, Cushman (A 291).
One station: 417.
Three large and well-developed specimens from St. 417, 1410 fathoms, off the coast
of Coats Land.
This is a well-known Indo-Pacific species which was recorded (A 291) from the Drake
Strait, where its presence was regarded as evidence of Pacific influence. Its occurrence
so much farther south, and near the Antarctic coast-line, indicates that there is an inflow
of Pacific water into this area of the Weddell Sea.
Not recorded by Pearcey inside the convergence, but “‘sparingly”’ at St. 346 on the
Burdwood Bank.
Genus Ehrenbergina, Reuss, 1850
123. Ehrenbergina bradyi, Cushman (F 166) (SG 194) (A 294).
One station: 447.
Not uncommon, but small.
Pearcey’s record of E. serrata, Reuss, at St. 342 probably refers to this species.
124. Ehrenbergina hystrix, Brady, var. glabra, Heron-Allen and Earland (F 165)
(SG 192) (A 296).
‘Two stations: 417, 418.
Very rare at both stations, which are on the Continental slope off Coats Land. It
may be more abundant in shallower water inshore.
Family LAGENIDAE
Subfamily LAGENINAE
Genus Lagena, Walker and Boys, 1784
Note. For greater convenience the species are arranged in alphabetical order.
125. Lagena acuticosta, Reuss (F 196) (SG 197) (A 302).
Three stations: 417, 421, 447.
Many good specimens at Sts. 417 and 421; two at St. 447.
Pearceyc342) rare!
126. Lagena alveolata, Brady (A 303).
Three stations: 417, 418, 447.
Frequent and typical at St. 417; rare at the other stations.
127. Lagena alveolata var. separans, Sidebottom (F 246) (A 305) (Plate I, figs. 41, 42).
One station: 421.
Five typical specimens at St. 421 in the south-east corner of the Weddell Sea;
evidence of the penetration of Pacific water.
SYSTEMATIC ACCOUNT 45
128. Lagena alveolata var. substriata, Brady (SG 198) (A 306) (Plate I, figs. 43, 44).
One station: 417.
Many excellent specimens of this Pacific form at St. 417.
129. Lagena annectens, Burrows and Holland (F 215) (SG 199).
Two stations: 417, 447.
One large, weak specimen at St. 417; several examples at St. 447.
130. Lagena apiculata (Reuss) (F 174) (SG 200) (A 308).
Three stations: 417, 421, 447.
The best and most typical specimens at St. 417, where it is rare. Frequent in elongate
varieties at Sts. 421 and 447.
Pearcey: 342 ‘‘sparingly”’.
131. Lagena aspera, Reuss (F 182) (A 309).
One station: 421.
A single thin-walled specimen with the spines arranged in regular rows, not unlike
Sidebottom’s figure from the South West Pacific (S. 1912, etc., LSP, 1913, p. 167,
plaexv, fg. 11):
132. Lagena biancae (Seguenza) (F 210) (SG 202) (A 314).
Three stations: 417, 421, 447.
Frequent at St. 417; rare elsewhere; as usual showing great range of variation.
Pearcey recorded this species as L. laevigata (Reuss) (non d’Orbigny) only outside the
convergence.
133. Lagena catenulata, Reuss (F 201) (SG 205) (A 318).
One station: 421.
A single weak specimen.
134. Lagena clavata (d’Orbigny) (F 178) (A 321).
One station: 286.
A single specimen.
135. Lagena clavulus, Heron-Allen and Earland (A 322) (Plate I, fig. 45).
One station: 421.
A specimen doubtfully referred to this species. It has a long neck and the projections
are in some cases connected by what appear to be the remains of wings extending down
the sides of the test. They may represent tubules passing through the wings of a test of
the /agenoides group.
136. Lagena costata (Williamson) (F 195) (SG 207) (A 325).
One station: 421.
Two small but typical specimens.
46 = DISCOVERY REPORTS
137. Lagena desmophora, Rymer Jones (A 328) (Plate I, fig. 46).
One station: 286.
Two small specimens with exceptionally long necks and weak ornament resembling
fig. 44 in A 328 were found at St. 286.
Pearcey records the species outside the convergence only.
138. Lagena exsculpta, Brady (A 330).
Three stations: 286, 421, 447.
Rare everywhere; typical but small at Sts. 286 and 421; larger but less typical at St.
447. Pearcey: 342, 447 ‘“‘rare”’.
139. Lagena felsinea, Fornasini (SG 212) (A 332).
Four stations: 286, 417, 421, 447.
Very rare but typical.
140. Lagena fimbriata, Brady var. occlusa, Sidebottom (F 233) (A 334).
Two stations: 286, 417.
A single typical specimen at each station.
141. Lagena formosa, Schwager (SG 214) (A 335).
Two stations: 421, 447.
Two large and typical specimens at St. 421; a smaller example at St. 447.
Pearcey: 417 “‘very rare’’.
142. Lagena foveolata, Reuss (F 204) (SG 216) (A 337).
‘Two stations: 421, 447.
Very rare, but good slender specimens at St. 447.
143. Lagena foveolata var. paradoxa, Sidebottom (A 338).
One station: 421.
Many good specimens of this distinctly Pacific form.
144. Lagena globosa (Montagu) (F 169) (SG 217) (A 340).
Four stations: 286, 417, 421, 447.
Common at Sts. 417 and 421, and frequent at the other stations. All varieties are
represented, including compressed and fissurine forms.
Peatcey 3417 rare”.
145. Lagena globosa var. emaciata, Reuss (A 341).
One station: 447.
A single specimen.
146. Lagena globosa, var. setosa, Earland (A 342).
Three stations: 300, 417, 421.
Three good specimens at St. 421; single examples elsewhere.
SYSTEMATIC ACCOUNT 47
147. Lagena gracilis, Williamson (F 185) (SG 218) (A 344).
Two stations: 417, 421.
Good and typical specimens are frequent at St. 417; rarer at St. 421.
148. Lagena gracillima (Seguenza) (F 177) (SG 219) (A 345).
One station: 286.
A single specimen.
149. Lagena hexagona (Williamson) (F 202) (SG 222) (A 349).
One station: 421.
Very rare. The specimens have high walls surrounding the hexagonal pits.
150. Lagena hispida, Reuss (F 181) (A 350).
Two stations: 417, 418.
A single very weak specimen of normal type at each station.
151. Lagena hispidula, Cushman (F 180) (SG 223) (A 351).
Three stations: 417, 421, 447.
Frequent at Sts. 417 and 421; rarer at St. 447 where the few specimens were large
and very typical.
152. Lagena laevis (Montagu) (F 179) (SG 224) (A 355) (Plate I, fig. 47).
Four stations: 286, 417, 418, 421.
Frequent and typical except at St. 418 where only two specimens were found, one
being exceptionally large. At St. 286 a variety occurs, characterized by a long neck and
globular body with base bearing a few short spines. It is similar to L. globosa var. setosa
(No. 146), except for the long neck. :
Pearcey: 118 “few”’.
153. Lagena lagenoides (Williamson) (F 226) (SG 225) (A 356).
Two stations: 417, 447.
Many good specimens of the broad-winged, many-tubuled, deep-water form figured
in connection with F 226 were found at St. 417. At St. 447 asingle small and pauperate
specimen not unlike Sidebottom’s figure (S. 1912, etc., LSP, 1912, p. 413, pl. xix,
fig. 2).
154. Lagena lagenoides var. tenuistriata, Brady (F 228) (SG 226) (A 359).
One station: 417.
Many specimens at St. 417 representing two distinct forms; one is a striate variety
of the deep-water form referred to in No. 153; the other is a smaller, more inflated
- variety with narrow wing. They represent Brady’s figures 15 and 11 respectively
(B21884, EC, pl. lx, figs. 11, 15).
48 - DISCOVERY REPORTS
155. Lagena lamellata, Sidebottom (Plate I, figs. 48-50).
Lagena lamellata, Sidebottom, 1912, etc., LSP, 1912, p. 396, pl. xvi, figs. 24, 25; 1913, p. 177.
One station: 417.
Six specimens from 1410 fathoms off Coats Land are, I think, referable to this
obscure species. One specimen, practically undamaged, has a surface in agreement
with Sidebottom’s description, “‘ built up of thin plates, arranged in an irregular manner,
which, although rough, glisten to a certain extent’’. In the other specimens the outer
covering is more or less completely abraded, leaving a finely spinous wall, as also de-
scribed by Sidebottom. The unabraded wall has a very glittering appearance, as light is
reflected at different angles by the minute plates on the surface.
The types were from 505-533 fathoms in the south-west Pacific about 16° S, 179° E,
and apart from other specimens found in closely adjacent localities, I know of no further
record of its occurrence. The presence of the species off the Antarctic coast-line seems
to be definite proof of the penetration of Pacific water into the southern parts, at least,
of the Weddell Sea.
156. Lagena lineata (Williamson) (F 183) (SG 227) (A 361).
One station: 417.
A single specimen, rather strongly striate and with a tendency to a spiral twist of the
striae.
157. Lagena longispina, Brady.
Lagena longispina, Brady, 1879, etc., RRC, 1881, p. 61; 1884, FC, p. 454, pl. lvi, fig. 36 (only);
pl. lix, figs. 13, 14.
L. longispina, Pearcey, SNA, p. 1016.
One station: 286.
Two large specimens, one broken, having the long solid spines typical of Brady’s
species.
Pearcey’s only record is St. 459, outside the convergence. There is no evidence to
show whether his specimens represented Brady’s long-spined form, or the small form
separated as L. globosa var. setosa (see No. 146 and A 342).
158. Lagena marginata (Walker and Boys) (F 221) (SG 232) (A 364).
Three stations: 417, 418, 421.
Frequent at St. 417 with moderately broad carina; very rare but with broad carina
at St. 421; very rare and weak at St. 418.
Pearcey: 342 “‘sparingly”’.
159. Lagena marginata var. cushmani, Wiesner (A 365).
One station: 417.
Several very good specimens.
160. Lagena marginata var. echinata (Seguenza) (Plate I, figs. 51-53).
Fissurina echinata, Seguenza, 1862, FMMM, p. 58, pl. i, fig. 54.
One station: 421.
SYSTEMATIC ACCOUNT 49
Six specimens found at St. 421 appear to be referable to Seguenza’s species, which
was described from a yellow Miocene marl from Sicily.
Seguenza describes his form as ovate, rough, rounded at the base, bluntly pointed at
the oral extremity; surface roughly spinous, with a very obtusely rounded keel. His
single figure illustrating the side view does not indicate much compression of the test;
indeed he described the shell as only slightly compressed because the carina is very
obtuse and rounded.
His specimens were presumably worn. The Scotia series shows every range between
a specimen like Seguenza’s figure, and one in which there is a distinctly produced neck
from which a delicate carina extends down the edges for three-quarters of the length of
the test. In a perfect specimen the carina would probably extend round the base also.
The surface of the test is opaque, rough and finely hispid; the carina is glossy and
smooth.
Length 0-2 mm. Breadth 0-14 mm. Thickness 0-08 mm.
The variety is clearly allied to L. marginata, and its chief interest lies in the fact that
while the flask-shaped Lagenae exhibit a complete range of surface roughness between
L. aspera and L. hispida, there is so far as I remember no other record of a compressed
Lagena with a hispid surface.
The depth and distance from the Antarctic coast-line at St. 421 are, I think, sufficient
to forbid any question of regarding the specimens as derived from a Miocene deposit
ashore.
161. Lagena marginata var. raricostata, Sidebottom.
Lagena marginata, Walker and Boys, var.nov. raricostata, Sidebottom, 1912, etc., LSP, 1912,
p- 408, pl. xviii, figs. 8, 9; 1913, p. 187.
One station: 447.
A single good specimen.
162. Lagena marginata var. semimarginata, Reuss (F 222) (A 369).
One station: 447.
A single specimen.
163. Lagena marginata var. spinifera, Earland (A 370).
Two stations: 421, 447.
Frequent at St. 421; rare but large at St. 447.
164. Lagena orbignyana (Seguenza) (IF 240) (SG 236) (A 374) (Plate I, figs. 54, 55,
60, 61).
Three stations: 417, 418, 421.
Rare at St. 417, where two distinct forms occur. One is the typical North Atlantic
variety with oval body and three feeble keels of approximately equal breadth figured by
Brady (B. 1884, FC, pl. lix, fig. 25). The other has an almost circular body, and the
median keel is very wide, especially round the base. It seems to resemble the variety
separated by Cushman (C. 1910, etc., FNP, 1913, p. 45, pl. xxiii, fig. 1) as var. alata,
D XIII /
50 ; DISCOVERY REPORTS
but in view of the fact that this name is preoccupied by Reuss (1851) for a different
organism, and the enormous amount of variation in this species, I have not separated
the forms.
All the specimens at St. 417 are large, as also was a single specimen of the broad-
keeled form found at St. 418. Small specimens of the same form are frequent at St. 421.
Pearcey: 417, 447 “rare”’.
165. Lagena orbignyana var. walleriana, J. Wright (Plate I, figs. 56-59).
Lagena orbignyana var. walleriana, J. Wright, 1886, LB, p. 611; 1891, SWI, p. 481, pl. xx,
figs. 8 a, b.
L. orbignyana var. walleriana, Sidebottom, 1912, etc., LSP, 1912, p. 417, pl. xix, fig. 21; 1913,
p. 195.
One station: 417.
A small form, frequent at St. 417, resembles Wright’s variety except in one important
particular. The carinae are not continuous but in the basal area are traversed by bars,
up to four in number, which separate the intercarinal spaces into rectangular pits. There
are generally six of such pits occupying the basal margin of the shell, the central pits
being larger in such cases, but sometimes there are only three cross-bars giving four pits.
It was not seen at any other station, and I have not met with the form before.
This subvariety is very interesting, but the distinctive feature of Wright’s variety, the
central solid umbo of shell substance, is so strongly marked, that I have not thought it
worth further distinction.
166. Lagena palliolata, Earland (A 377).
One station: 447.
A single specimen. The type was from deep water in the Drake Strait.
167. Lagena quadrilatera, Earland (A 381).
Two stations: 417, 421.
A single typical specimen at each station. The only previous records are in the Ross
Sea and in Drake Strait, so this extension of range is of great interest.
168. Lagena rizzae (Seguenza) (F 235).
One station: 421.
A single specimen.
169. Lagena schlichti (A. Silvestri) (F 225) (SG 241) (A 386).
Three stations: 417, 418, 421.
Common at St. 417, some of the specimens being large; rare, or very rare, and smaller
at the remaining stations.
170. Lagena seguenziana, Fornasini (A 388).
One station: 417.
A single typical specimen.
SYSTEMATIC ACCOUNT 51
171. Lagena semilineata, J. Wright (A 3809).
One station: 421.
Frequent specimens.
172. Lagena sidebottomi, Earland (A 393).
One station: 286.
Two good specimens. This is a most typical Pacific species, the outer range of which
has hitherto been the recent record in Drake Strait (A 393). Its occurrence at a station
in the middle of the Weddell Sea is therefore a noteworthy extension.
173. Lagena squamosa (Montagu) (F 197) (SG 243) (A 394).
One station: 417.
A single weak specimen.
Pearcey: 417 ‘‘not in any numbers”’.
174. Lagena staphyllearia (Schwager) (F 224) (SG 245) (A 397).
Five stations: 286, 417, 418, 421, 447.
Rare or very rare at all stations, but excellent specimens. The typical form with three
basal spines represents the species at Sts. 417 and 418, and is larger than usual. The
two-spined variety only is present at Sts. 286 and 447; both occur together at St. 421.
Pearcey: 447 “‘rare’’.
175. Lagena stelligera, Brady (A 398) (Plate I, fig. 62).
Three stations: 286, 421, 447.
Common at St. 421, not infrequent at the other stations. As usual there is considerable
variation, but the majority of specimens at all stations are more or less devoid of basal
costae, and both the neck and the basal tubule are longer than usual. Sidebottom’s
figure (S. 1912, etc., LSP, 1912, pl. xvi, fig. 2) represents the most frequent variation.
176. Lagena stelligera var. eccentrica, Sidebottom (A 399) (Plate I, figs. 63, 64).
‘Two stations: 417, 421.
Three large and typical specimens at St. 417. At St. 421 two specimens of a variation
presenting a stout blunt spine in the centre of the basal ring.
177. Lagena stewartii, J. Wright (F 171) (SG 246) (A 401).
One station: 417.
A single good specimen.
178. Lagena striata (d’Orbigny) (F 188) (SG 247) (A 402).
‘Two stations: 313, 417.
Very rare: never more than two specimens at a station, and all of the long flask-
shaped form figured by Williamson.
52 ; DISCOVERY REPORTS
179. Lagena sulcata (Walker and Jacob) (F 189) (SG 248) (A 405).
Three stations: 417, 418, 421.
Frequent at St. 421, and very variable in the development and number of the costae.
A single doubtful specimen at St. 418, and two of a curious compressed variety at St. 417.
180. Lagena ventricosa, A. Silvestri (SG 249) (A 409).
Four stations: 417, 418, 421, 447.
Common and large at St. 447; frequent good specimens at St. 417; rare or very rare
at the other stations.
Subfamily NODOSARIINAE
Genus Nodosaria, Lamarck, 1812
181. Nodosaria calomorpha, Reuss (F 252) (SG 254) (A 413).
One station: 417.
A single specimen of two chambers only.
182. Nodosaria communis, d’Orbigny (F 254) (SG 256) (A 415).
‘Two stations: 286, 421.
Only single small specimens.
183. Nodosaria mucronata, Neugeboren (A 417).
One station: 447.
A single specimen.
Pearcey "407 otate
184. Nodosaria pauperata (d’Orbigny) (F 255) (SG 257) (A 418).
Three stations: 417, 421, 447.
A few large specimens in fragments at St. 417; single examples at the other stations,
large (microspheric) at St. 447.
185. Nodosaria raphanistrum (Linné) var. (A 421).
One station: 417.
A few specimens of the curious little variety figured in A 421 were found at St. 417,
off Coats Land. Previously known from the Ross Sea and Drake Strait, its presence
there, taken in conjunction with other species of like distribution (e.g. Nos. 122, 127,
128, 137, 143, 155, 167, etc.), seems evidence of the circulation of Pacific water into the
most southern areas of the Weddell Sea.
Genus Marginulina, d’Orbigny, 1826
186. Marginulina glabra, d’Orbigny (SG 261).
Three stations: 417, 418, 447.
Three very good specimens at Sts. 417 and 418, and one very small example at
St. 447.
SYSTEMATIC ACCOUNT 53
Genus Cristellaria, Lamarck, 1812
187. Cristellaria crepidula (Fichtel and Moll) (F 268) (SG 262) (A 424).
One station: 417.
A single small specimen.
188. Cristellaria acutauricularis (Fichtel and Moll) (F 270) (A 425).
One station: 447.
A single small specimen from St. 447, diatom ooze, 2103 fathoms. The species is
universally distributed, but always rare.
189. Cristellaria obtusata, Reuss (F 272) (A 427).
One station: 447.
Two small specimens.
190. Cristellaria gibba, d’Orbigny (F 274) (SG 263) (A 431).
One station: 417.
Two small specimens.
191. Cristellaria cultrata (Montfort) (F 278) (SG 264) (A 433).
One station: 417.
A single specimen.
192. Cristellaria convergens, Bornemann (F 281) (SG 265) (A 436).
Two stations: 421, 447.
Very rare but typical at both stations.
Peatcey 4374 tate’, 342 few’, 418 “rate”?, 447 “rate”.
Subfamily POL YMORPHININAE
Genus Glandulina, d’Orbigny, 1826
193. Glandulina laevigata, d’Orbigny (F 248) (SG 252) (A 438).
One station: 417.
Only two broken specimens.
Genus Polymorphina, d’Orbigny, 1826
194. Polymorphina cylindroides, Roemer (A 443).
Two stations: 286, 313.
A single exceptionally large specimen at St. 313 and a very small example at St. 286.
195. Polymorphina angusta, Egger (A 445).
One station: 447.
Frequent small specimens.
Pearcey: 342, 447 “rare’’.
54 : DISCOVERY REPORTS
196. Polymorphina problema, d’Orbigny (F 289) (A 447).
One station: 418.
A single large specimen.
197. Polymorphina extensa, Cushman (A 448).
One station: 417.
One dead and worn specimen.
Genus Uvigerina, d’Orbigny, 1826
198. Uvigerina angulosa, Williamson (F 301) (SG 274) (A 454).
‘Two stations: 286, 418.
Two specimens at St. 418 and one at St. 286, all very small.
Family GLOBIGERINIDAE
Genus Globigerina, d’Orbigny, 1826
199. Globigerina bulloides, d’Orbigny (F 304) (SG 276) (A 456).
Four stations: 312, 417, 418, 447.
Frequent but small at St. 447, near the convergence; rare or very rare elsewhere
except at Sts. 417 and 418, off Coats Land in 71° 22'S to 71° 32’ S, where it is not
uncommon. Its presence in such a high latitude indicates an inflow of warm water.
Pearcey: 338, 342, 417, 421 (frequency not stated).
200. Globigerina triloba, Reuss (F 305) (SG 277) (A 457).
Three stations: 286, 421, 447.
Frequent and large at St. 447, smaller at St. 421. Only two small specimens at
St. 286.
Pearcey: 342 “few”’.
201. Globigerina inflata, d’Orbigny (F 306) (SG 278) (A 459).
Two stations: 313, 447.
A single large specimen at St. 313; frequent at St. 447.
Pearcey: 342 “fairly common”’.
202. Globigerina dutertrei, d’Orbigny (F 307) (SG 279) (A 460).
Six stations: 313, 417, 418, 421, 438, 447.
Frequent at Sts. 417 and 418, rare or very rare elsewhere.
Pearcey: 286, 300, 313, 338, 342, 387, 417, 418, 420, 421, 447 ‘‘in smaller or greater
”
numbers ’”’.
203. Globigerina conglomerata, Schwager (F 308) (SG 280) (A 461).
Five stations: 312, 313, 417, 418, 447.
Common at St. 417, frequent to rare elsewhere.
This is almost certainly the species recorded by Pearcey under the name G. dubia,
Egger, “rare” at St. 421.
SYSTEMATIC ACCOUNT 55
204. Globigerina pachyderma (Ehrenberg) (F 310) (SG 281) (A 464).
Eleven stations: 226, 286, 300, 312, 313, 338, 417, 418, 421, 422, 447.
Very common at St. 421; common at Sts. 417 and 447; frequent at Sts. 286, 313,
418 and 422; very rare elsewhere, sometimes only a single specimen. Abnormal
specimens such as those referred to in SG, p. 120, and A, p. 175, were observed at
Sts. 417, 421, 422 and 447.
Pearcey: 300, 313, 338, 342, 387, 417, 420 ““more or less abundantly”.
Genus Pullenia, Parker and Jones, 1862
205. Pullenia sphaeroides (d’Orbigny) (F 315) (SG 286) (A 467).
Four stations: 286, 417, 421, 447.
Common at Sts. 421 and 447, where both the type and a compressed variety occur
together. The spherical type is unusually large at St. 447; the compressed form is
always smaller than the type.
Pearcey: 342, 420, 421, 447 “sparingly’”’.
206. Pullenia subcarinata (d’Orbigny) (F 316) (SG 287) (A 468).
Three stations: 417, 421, 447.
Rare at all stations. At Sts. 417 and 421 all the specimens were of the compressed
quinqueloba type, but the number of chambers varied from five to seven. At St. 447
both this form and the typical inflated P. subcarinata occur together, and with inter-
mediate variations.
Not recorded by Pearcey within the convergence under either specific name.
Genus Sphaeroidina, d’Orbigny, 1826
207. Sphaeroidina bulloides, d’Orbigny (SG 289) (A 469).
One station: 417.
One typical specimen of average size. This is a great southward extension of the dis-
tribution of the species by 7° latitude, and is evidence of the penetration of warm water
into the extreme south of the Weddell Sea.
Family ROTALIIDAE
Subfamily ROTALIINAE
Genus Discorbis, Lamarck, 1804
208. Discorbis globularis (d’Orbigny) (F 331) (SG 294) (A 474).
One station: 406.
A single typical specimen from 1131 fathoms, off Coats Land.
Genus Cibicides, Montfort, 1808
209. Cibicides refulgens, Montfort (F 355) (SG 303) (A 487).
One station: 417.
56 DISCOVERY REPORTS
A single typical specimen. The rarity of the species, usually abundant in Antarctic
material, is probably due as much to the nature of the bottom as the depth.
210. Cibicides lobatulus (Walker and Jacob) (F 356) (SG 304) (A 489).
Three stations: 406, 417, 421.
A single normal specimen at St. 406. At St. 417 the species is rare, but present both
in the typical form and in the pauperate variety figured and described from deep water
in the Drake Strait (A 489). Very rare and weak at St. 421.
Pearcey: 342, 447 ‘‘sparingly”’. He also records its variety Cibicides (Truncatulina)
tenuimargo (Brady) “sparingly”’ at St. 417. I did not observe this.
211. Cibicides wuellerstorfi (Schwager) (F 361) (SG 306) (A 492).
‘Two stations: 417, 418.
Common at St. 417: frequent at St. 418.
Pearcey : 300, 417, 420, 421 “sparingly”.
212. Cibicides aknerianus (d’Orbigny) (F 362) (SG 307) (A 493).
One station: 417.
Only a single specimen.
213. Cibicides pseudoungerianus, Cushman (F 363) (SG 308) (A 494).
Three stations: 417, 421, 447.
Frequent at all stations, but the specimens are small at St. 447.
Pearcey: 313 ‘“‘sparingly”’ under the name 7runcatulina ungeriana (d’Orbigny).
Genus Globorotalia, Cushman, 1927
214. Globorotalia crassa (d’Orbigny) (F 376) (SG 317) (A 500).
One station: 301.
A single small specimen.
Pearcey: 342 “‘few”’.
Genus Eponides, Montfort, 1808
215. Eponides umbonatus (Reuss) (F 386) (SG 322) (A 502).
Five stations: 286, 417, 418, 421, 447.
Common and large at St. 421; frequent at Sts. 417, 418 and 447; very rare at St. 286.
Wherever the species is at all abundant, both the type of Reuss and the thin-walled
form described by Brady as Truncatulina tenera (see F 386) are found together in varying
proportions, and with intermediate variations. At St. 421 the type predominates and
grows to a much larger size than tenera. At Sts. 417 and 418 tenera predominates and
all specimens are rather undersized. At Sts. 286 and 447 tenera was not observed.
Pearcey records the forms separately, but did not find the type wmbonatus within the
convergence. Truncatulina tenera is recorded as “‘rare”’ at Sts. 342, 417.
SYSTEMATIC ACCOUNT 57
216. Eponides karsteni (Reuss) (F 391) (SG 324) (A 503).
Three stations: 338, 417, 421.
Extremely rare: only a single specimen at each station.
earceys 447." tare -.
217. Eponides weddellensis, sp.n. (Plate I, figs. 65-67).
Three stations: 286, 417, 421.
Test minute, biconvex, the dorsal side exhibiting 3-4 convolutions is higher than the
ventral and has five chambers in the last convolution; sutures distinct, flush, their white
colour contrasting with the hyaline texture of the chambers; peripheral edge rounded;
ventral side exhibiting only the five chambers of the last convolution ; sutures depressed ;
aperture a minute slit on the inner edge of the final chamber on the ventral side.
Breadth about 0-16 mm. Height about 0-12 mm.
Fairly frequent at all three stations, the best specimens at St. 421. The species also
occurs at St. 459, outside the convergence, and may have a wide distribution in deep
water. Owing to its minute size it would be easily overlooked.
This little species is probably allied to F. karsteni (Reuss) and closely resembles the
small form of that species figured by Brady from Magellan Straits (B. 1884, FC, pl. cv,
fig. 8), which is common in many deep-water deposits from the North Atlantic and else-
where. But it differs in having an unbroken peripheral edge, and never has the ventral
peripheral line shown in the Challenger figure.
218. Eponides exiguus (Brady) (F 387) (SG 323) (A 504).
Five stations: 286, 417, 418, 421, 447.
Only a single specimen at St. 286, but frequent to common at the remaining stations.
Pearcey : 342 ‘‘few’’, 417 ““common”’, 447 “‘few”’.
219. Eponides tumidulus (Brady) (F 366) (SG 312) (A 505).
Four stations: 286, 417, 421, 447.
Rare, except at St. 421, where good specimens were frequent.
220. Eponides bradyi, Earland (F 367) (SG 313) (A 506).
Six stations: 286, 300, 313, 421, 422, 447.
Common at Sts. 286 and 421 and frequent at St. 447, rare at the remaining stations.
The best specimens, i.e. those in best condition, were observed at Sts. 313, 421 and 447,
but the majority of the specimens at all stations were dead and often decomposing shells.
Pearcey records the species under the name Truncatulina pygmaea, Hantken, at Sts.
300, 342, 420 and 447 “few”’.
Genus Laticarinina, Galloway and Wissler, 1927
221. Laticarinina pauperata (Parker and Jones) (SG 326) (A 509).
One station: 417.
Two large, dead and rather worn, specimens.
DXIII
58 j DISCOVERY REPORTS
Genus Rotalia, Lamarck, 1804
222. Rotalia orbicularis (d’Orbigny) (A 511).
One station: 421.
A good and typical specimen.
223. Rotalia soldanii, d’Orbigny (F 3944) (SG 328) (A 512).
Two stations: 417, 447.
Frequent at both stations, and exceptionally large at St. 417.
Pearcey: 342 ‘“‘common’’, 447 “rare”’.
Family NUMMULINIDAE
Subfamily NONIONINAE
Genus Nonion, Montfort, 1808
224. Nonion pompilioides (Fichtel and Moll) (F 402) (SG 333) (A 515).
Three stations: 338, 421, 447.
Frequent at St. 447, rare at the other stations.
Pearcey: 286, 342, 447 “sparingly”.
225. Nonion stelliger (d’Orbigny) (F 404) (SG 335) (A 516).
One station: 418.
Two weak specimens only.
Pearcey: 417 ‘‘a few specimens”.
226. Nonion scapha (Fichtel and Moll) (F 407) (SG 338) (A 520).
Two stations: 312, 417.
Extremely rare and far from typical. The few specimens found are so asymmetrical
that they are almost inseparable from Nonionella iridea (No. 227). I am convinced that
Nonionella has no zoological value as a genus.
Genus Nonionella, Cushman, 1926
227. Nonionella iridea, Heron-Allen and Earland (F 410) (SG 339) (A 522).
Three stations: 312, 417, 418.
Frequent at Sts. 417 and 418; a single specimen at St. 312.
I cannot think how Pearcey can have overlooked this little form or its closely allied
relative Nonion scapha, with which he might have confused it, the two species being
zoologically very nearly akin.
Genus Elphidium, Montfort, 1808
228. Elphidium excavatum (Terquem) (F 413) (A 525).
One station: 338.
Two small specimens from St. 338 in the Scotia Sea, but not recorded in the Weddell
Sea.
Pearcey does not record any species of Elphidium within the convergence.
SUPPLEMENTARY BIBLIOGRAPHY 59
SUPPLEMENTARY BIBLIOGRAPHY
See Part I, pp. 443-51; Part II, p. 133; Part III, pp. 192-4.
The following are the titles of papers other than those referred to in Parts I, IL and III of this report.
B. 1882, K. H. B. Brapy. Note on Keramosphaera, a new Type of Porcellanous Foraminifera. Ann. Mag.
Nat. Hist., ser. 5, x, 1882, pp. 242-5, pl. xiii.
B. 1918, SLS. W.S. Bruce. Station Log of the S.Y. ‘Scotia’, 1902-1904. Rep. Scientific Results of the
Scottish National Antarctic Expedition, 1918, 1, pt. i, pp. 1-28.
C. 1875, etc., M. W. B. Carpenter. The Microscope and its Revelations. London. 5th ed., 1875; 6th ed.,
1881.
E. 1934, A. A. EarLaND. Foraminifera, Part III. The Falklands Sector of the Antarctic (excluding South
Georgia). Discovery Reports, 1934, X, pp. 1-208, pls. i-x.
M. and H. 1912, DO. JoHN Murray and Jouan Hyjort. The Depths of the Ocean. A general account of
the modern science of Oceanography based largely on the scientific researches of the Norwegian
steamer ‘Michael Sars’ in the North Atlantic. London, 1gr2.
N. 1876, V. A. M. Norman in J. G. Jerrreys’ Preliminary Report of the Biological Results of a Cruise in
H.M.S. ‘Valorous’ to Davis Strait in 1875. Proc. Roy. Soc., London, xxv, 1876, pp. 202-15.
P. 1914, SNA. F.G. Pearcey. Foraminifera of the Scottish National Antarctic Expedition. Trans. Roy. Soc.
Edinburgh, xLix, 1914, pp. 991-1044, pls. 1, il.
P. 1905, DSD. J. H. Harvey Pirte. Deep-Sea Deposits of the South Atlantic Ocean and Weddell Sea.
Scottish Geographical Magazine, August 1905, pp. 1-5, chart.
S. 1901, PC. E.SpanpEL. Die Foraminiferen des Permo-Carbon von Hooser, Kansas, Nord Amertka. Abhand.
Nat. ges. Niirnberg, 1g01, pp. 177-94, text-figs. I-10.
W. 1886, LB. J. Wricur. (Report on Foraminifera obtained in the cruise of the ‘Lord Bandon’) in First
Report on the Marine Fauna of the South-west of Ireland—Rhizopoda. Proc. R. Irish Acad., ser. 2,
Iv, 1886, pp. 607-14.
60
REPORT ON SOME CRYSTALLINE COMPONENTS OF
THE WEDDELL SEA DEPOSITS
By F. A. BANNISTER, M.A.
WITH CHEMICAL ANALYSES BY M. H. HEY, M.A., B.Sc.
Assistant Keepers in the Mineral Department of the British Museum (Natural History)
(Plates II, II A)
URING his study of the Foraminifera present in oceanic bottom samples brought back
by the Scotia Expedition (1902-4) from the Weddell Sea, Mr A. Earland picked out
a number of minute crystals and crystalline nodules which he separated by external
characters into three groups. A brief description of these crystalline components and
an account of their examination by optical and X-ray methods seemed desirable chiefly
because the substances identified have not hitherto been recorded from ocean bottom
deposits.
HYDRATED CALCIUM OXALATE, CaC,0,.2H,O
The first group consists of minute “‘envelope”’ crystals recorded from a number of
stations in the very deep water of the central Weddell Sea, from depths of 2425-2739
fathoms (4434-5008 m.) (Plate II, fig. 1). These crystals are transparent, colourless,
tetragonal bipyramids varying in size from 0-2 x 0-I to 0-3 x 0-15 mm. When immersed
in a liquid and viewed under the microscope they present sharp, square outlines with
well-marked diagonals showing the intersection of the four uppermost pyramid faces.
Intergrowths of two or more individuals are not uncommon but the grouping appears
to be accidental and not in conformance with any twin-law. The “‘envelope”’ crystals
are sparsely distributed in the deep-sea deposits. A gram of unpicked material from
St. 286 yielded about fifty crystals weighing only half a milligram, the mineral residue
consisting principally of fragments and rounded pebbles of clear, colourless quartz.
Fragments of green hornblende, pink almandine, orange hessonite, brown biotite and
glauconite were also detected.
When examined with convergent polarized light each “‘envelope”’ crystal gives a
positive uniaxial figure consisting of a black cross surrounded by two interference rings ;
approximate birefringence = 0-02. If monochlorobenzene be used as the immersion
liquid the crystal outline completely vanishes; hence the refractive index w = 1-523
+ 0-005. The specific gravity could not be determined by balancing in a mixture of
bromoform and benzene owing to their minute size and lack of colour. Several, how-
ever, were mounted on thin glass fibres and each in turn accurately centred in a parallel
beam of light restricted in diameter by an iris diaphragm and pin-hole collimator. By
such means it was possible to measure the angle between pyramid faces. The average
value for the angle between a pyramid face r and the basal plane c (001) is cr = 30° 35’.
At this stage the tetragonal symmetry of a crystal was confirmed by a Laue photo-
graph taken with the X-ray beam passing along the c axis [oor]. Rotation photographs
CRYSTALLINE COMPONENTS 61
were also taken with a square edge vertical (Plate II, fig. 3), with a diagonal vertical and
also about the c axis [oor] (Plate II, fig. 4). The smallest tetragonal unit cell which can
be assigned to the crystals on the basis of these photographs has the dimensions a 12-40,
¢ 7°37 + 0-02 A. The indices of the pyramid faces are therefore {101}. The calculated
axial ratio is c: a = 0-594: 1 corresponding to a calculated cr angle = 30° 421’, in close
agreement with the goniometric value, 30° 35’. Rotation and oscillation photographs
about the [100] axis were then indexed and the unit cell found to possess the symmetry
of the space-group Cj, = I 4/m.
The optical and crystallographic data so far obtained show that the crystals cannot be
identified with any known tetragonal mineral. Fortunately, determinative data for all
organic and inorganic substances known to possess tetragonal symmetry have recently
been compiled by Hey,' and independently by J. D. H. Donnay and J. Mélon (1934).
These data follow the determinative method suggested by T. V. Barker (1930). Allow-
ing a possible error of + 1° in the measured cr value, fifteen compounds are found to
have cr values ranging from 29} to 313°. Several of these are soluble in water and there-
fore are excluded; of the remainder only the salt commonly known as calcium oxalate
trihydrate, CaC,O,.3H,O, possesses the same appearance and optical properties as the
crystals under consideration. The cr value tabulated by Donnay and Mélon for
CaC,O,.3H,O is 30° 7’. The presence of calcium in the deep-sea crystals was readily
confirmed by dissolving one in a drop of dilute sulphuric acid and obtaining gypsum
needles. A test for the oxalic acid radicle would, however, have consumed most of the
crystals so far separated from the Weddell Sea deposits; certainly a complete chemical
analysis was out of the question.”
A less direct method of confirming the above identification was therefore sought. The
methods described by A. Souchay and E. Lenssen (1856) for synthesizing CaC,O, .3H,O
did not promise a product sufficiently pure for chemical work. “‘Envelope”’ crystals
are also present in the cells of certain plants (A. W. P. Zimmerman, 1892), and in the gall
and urine of many mammals and fish. No reference, however, has yet been found to
crystals of plant or animal origin measuring more than 0-17 mm. across, so that a
separation of the requisite amount for exact chemical analysis would probably be
impossible. It was suggested by Mr Hey that larger crystals of the compound might
constitute the coating of certain renal calculi. This suggestion proved valuable. At the
invitation of the Curator of the Royal College of Surgeons I was permitted to examine
all their specimens of renal calculi taken from human bladders. ‘lwo calcium oxalate
calculi were found coated with platy crystals, and these were kindly loaned to the
Mineral Department for investigation.
The calculi differ somewhat in appearance; one, catalogue number C. go, is spherical
in shape, diameter 25 mm., and has a white powdery surface encrusted with white
translucent platy crystals with clear edges. The second calculus (an unregistered dupli-
cate) is roughly ellipsoidal in shape, measures 25 « 15 mm., and is encrusted with pale
brown crystals of the same type. The matrix like that of C. go is white but more com-
pact. Golding Bird (1842) has described similar renal calculi from the Guy’s Hospital
1 Unpublished. 2 The crystals weigh approximately 1 x 10~° gm. each.
62 ; DISCOVERY REPORTS
Museum collection. He identified the calcium oxalate crystals with the much smaller
‘“envelope”’ crystals found in human urine. ‘‘ Sometimes these crystals are opaque and
the octahedron is remarkably flattened: the calculus then looks as if studded with pearl-
spar.” His careful study shows that the calcium oxalate may be intergrown with uric
acid, sodium urate, ammonium urate, magnesium ammonium phosphate, calctum phos-
phate or calcium carbonate. Golding Bird does not give, however, the dimensions of the
renal crystals of calcium oxalate. The crystals of both the calculi I have examined are
roughly square in outline, measuring 2—3 mm. across, but the pyramidal faces are curved
and the thickness of the crystals varies considerably owing to subparallel growth and
possibly twinning. Only small transparent wedge-shaped fragments suitable for optical
and X-ray work could be detached from the edges. These give a positive uniaxial picture
and yield approximate refractive indices w 1-523, « 1-544 (Becke method). The broken
fragments exhibit no well-marked cleavage directions; their hardness is about 4,
Mohs’ scale. Light reflections from the pyramid faces show that their curvature is due
to the presence of a large number of vicinal faces between (ror) and (oor). A few crystal
fragments give values cr varying from 30° 1’ to 30° 56’, but natural faces are too imper-
fect for refractive index measurements by the prism method and the fragments are too
small to be ground and polished. Gypsum needles crystallized from a solution of a
crystal fragment in sulphuric acid, and the residual liquid also decolorized a drop of
potassium permanganate solution. These preliminary measurements and chemical tests
therefore suggested the identity of the deep-sea crystals and the crystals from the renal
calculi.
X-ray rotation photographs of some crystal fragments from both the renal calculi were
then taken about the supposed [100] axis, i.e. about an edge of a square plate. All the
spots of each photograph correspond exactly in position and intensity with those of
a similar photograph of a deep-sea crystal. hese photographs constitute the most
reliable test of the identity of the two compounds since they do not depend upon the
perfection of crystal form but only upon the atomic arrangement within a crystal. A
chemical analysis of carefully selected fragments from the renal calculi should there-
fore reveal the chemical composition of the deep-sea crystals.
The specific gravities of crystal fragments from both calculi were separately de-
termined by balancing in mixtures of bromoform and benzene. Values varying from
1-98 to 2:00 were obtained, but no systematic difference could be detected between the
specific gravities of the white and pale-brown crystals. The first chemical analysis on
white crystals, sp. gr. 1-99, from C. 90, gave CaO 37:3 per cent (by ignition), C,O; 46-1
per cent (by titration with potassium permanganate solution), H,O 16-7 per cent (loss of
weight at 270° C.), total 100-1 per cent, which corresponds to a chemical formula
CaC,O,.1$H,O and was the first indication that the usually accepted trihydrate formula
might be incorrect. The formula relating the specific gravity d, atomic contents 7M and
unit-cell dimensions of a tetragonal compound is nM x 1-648/a2c = d. Since X-ray
rotation photographs of the deep-sea crystals and renal calculi crystals are identical the
values a 12-40, ¢ 7:37 A. may be inserted in the above formula. The value of // corre-
sponding to CaC,O,.13H,O is 155, the observed specific gravity is 1-99, so that
CRYSTALLINE COMPONENTS 63
m= 1:99 X 12°4* X 7:°37/155 x 1°648 = 8-82. Hence it appears that the tetragonal unit
cell contains approximately gCaC,O,.14H,O. The crystal-structure of oxalic acid and
many oxalates have now been worked by W. H. Zachariasen (1934) and S. B. Hendricks
(1935). In all of them the C,O, group has constant shape and dimensions. Both the
unit-cell dimensions and the space-group of the renal calculi crystals would lead us to
expect an even, not an odd number of C,O, groups per unit cell. It is difficult in the
face of the X-ray evidence to imagine how more than eight C,O, groups can be accom-
modated. Therefore either the observed specific gravity or the chemical composition or
both are inconsistent with the X-ray data.
In the meantime it had been found that the powdery material forming the matrix of
the renal calculi crystals effervesces when dissolved in dilute acids and gives a reaction
for phosphate. ‘This is also true of the crystals themselves, probably due to fine-grained
inclusions of the matrix. Moreover, a small residue of organic tissue remains after
solution of a calculus crystal or matrix in acid. The first analysis on the white crystals
must therefore be rejected, since it is clear that the presence of organic matter would
disturb the permanganate titration and give too high a value for the oxalate content.
The phosphate content of the crystals is also appreciable and possibly due to admixture
of the calcium oxalate salt with dahllite, 3Ca;(PO,),.CaCO,. The latter constituent is
extremely fine-grained and attempts to separate sufficient from the crystals for optical
tests or from the matrix for chemical analysis proved unsuccessful.
Two further chemical analyses were now made on pale-brown crystals, sp. gr. 1-99,
from the unnumbered calculus. It is impossible to determine the water content directly
since the crystals when dried at 270° C. still contain about 6 per cent H,O and if the
temperature is raised above 270° C. the oxalate begins to decompose. Nor can the
oxalate be determined by titration with potassium permanganate owing to interference
by included organic tissue. Accordingly the powdered crystals (10-06 mg. for analysis
I, 14°115 mg. for analysis 2) were weighed into a small crucible, dried at 270° C., heated
at 580° C. to decompose the oxalate, reweighed and then ignited at g50° C. The residue
was weighed and the phosphate content determined as ammonium phosphomolybdate.
The ignitions at 580 and g50° C. correspond to the following reactions:
(a) Hydrated calcium oxalate + dahllite 58°’ © CaCO, + Ca,(PO,). + CO + HO.
Loss of weight due to evolution of CO + H,O.
(6) CaCO, + Ca,(PO,), 22° © CaO + Ca,(PO,). + COg.
Loss of weight due to evolution of CO,.
Table I gives the results of the two analyses, together with the recalculated figures
allowing for deduction of dahllite. Table II shows that the two recalculated analyses
correspond approximately to CaC,O,.2H,O. The observed specific gravity 1-99 should
also be corrected for a content of 4 per cent dahllite, see Table I. Assuming a specific
gravity 3-1 for the latter constituent, the corrected value for the renal calculi crystals
is 1:94. The specific gravity calculated from the X-ray data and assuming that the tetra-
gonal unit cell contains 8CaC,O,.2H,O is 1-91. ‘The chemical and X-ray data are there-
64 : DISCOVERY REPORTS
fore in fair agreement considering the indirect methods used for analysis. There is no
doubt that the usually accepted trihydrate formula for the tetragonal calcium oxalate
is incorrect, and there is at least a strong probability that the formula should be
CaC,O,.2H,O.
Table I. Chemical analyses of renal calcium oxalate crystals, sp. gr. 1-99
F Recalculated to 100 °%, after
Observed percentages Equivalent to daductontopdabilte
Loss at | Loss at Dahl- | Cor CO+
S85 son. Isis TRE AON |) COE | HO.) SAO TPC iene
= =! 2 esi a 4 =
37°46 | 1-78 | 37°34 | 2342 | 4:32 | 35710 | 23:24 | 37°34 | 36°61 | 24:24 | 39°15
| 36°81 1°75 36-22 25°22 | 4:24 | 34:50 | 25°04 36:22 36-03 26:14 | 37°83
Table II
Theoretical percentage for CaC,O,
Analysis 1 | Analysis 2 Mean
H,O 2H,O 3H,0
CaO 36-61 36:03 36-32 38°39 34:18 30°80
CO, 24:24. 26°14 25°19 24°15 26°81 31°50
CO -- -- — 15°38 17:06 1Q'17
H,O — — — 29°67 21°95 12°33
CO +H,0 39°15 | 37°83 38-49 45°05 39°01 31°50
It is interesting to note that this conclusion is in agreement with the results of the
earliest workers (T. Graham, 1838). No completely satisfactory analysis of the salt,
however, has yet been published. A. Frey (1925), who claims to have produced artificial
crystals } mm. across, records a figure for the water content only and deduces the
formula CaC,O,.3H,O. It is not, however, obvious with what measure of success he
separated the tetragonal salt from associated products of crystallization. His optical
data are also at variance with mine; he gives w 1-552, « 1:583, presumably measured on
the artificial salt and it is significant that these values are close to those that would be
observed for a crystal of whewellite, CaC,O, . H,O, lying on the face x (011), viz. y’ 1°551,
a’ 1-592. In view of this disagreement in refractive index measurements some of his
identifications of the tetragonal crystals in plants must be accepted with reserve.
Many references to the presence of calcium oxalate in the waste products of plants
and animals also record the size of the “‘envelope”’ crystals. C. Schmidt (1846) studied
their formation in yeast covered by beer for many days. He also detected them in the
gall of rabbit, dog and pike. The crystals usually measured 0-01 x 0-005 mm. and were
never greater than 0-03 mm. across. Frey has observed crystals definitely of the tetra-
gonal form in Begonia species of size 0-023 x 0-013 mm. They are also a usual con-
stituent of human urine especially during the summer months. A sample of urine of
patients suffering from oxaluria kindly sent to me by Mr L. W. Proger, Pathological
Curator of the Royal College of Surgeons, shows many ‘‘envelope”’ crystals o-02-
0-025 mm. across, refractive index w = 1-52. Golding Bird (1843) made a microscopic
and chemical study of ‘‘envelope”’ crystals in human urine and was the first worker to
CRYSTALLINE COMPONENTS 65
record their low birefringence and approximate refractive index. It is also clear that he
recognized and was puzzled by the difference in optical properties of the “‘envelope”’
crystals and of the dumbbell-shaped spherulitic aggregates of whewellite sometimes
found in urine. Apparently he did not suspect the existence of two hydrates of calctum
oxalate. The largest envelope crystals detected in human urine by Golding Bird (1843)
measured 0-056 mm. across, but he found still larger light amber crystals, 0-17 mm.
across in horse urine (1845). These he preserved dry since they were
“invisible in
canada balsam”.
Although the deep-sea crystals are about ten times larger than those observed in plant
cells and ten times smaller than those from renal calculi, they are only a little larger than
urine crystals. The possibility that the deep-sea crystals have been deposited from the
urine of some marine organism is unlikely for three reasons. (i) Crystals deposited from
urine might well be expected in all oceanic bottom deposits, whereas Mr Earland’s
extensive study of ocean bottom deposits from all over the world so far shows that the
“envelope” crystals are not only a minor constituent but are restricted to very deep
water in the Weddell Sea. (ii) Louis Heitzmann (1934) has observed that urine and renal
crystals of calcium oxalate turn black at first on slow ignition owing to included organic
tissue. The deep-sea crystals, however, change to calcium carbonate and at a higher
temperature to lime without change of colour. (iii) The deep-sea crystals possess sharp
edges and faces free from scratches so that there seems little doubt that they were
formed in situ. It is obviously important to continue the search for calcium oxalate
crystals in other ocean bottom deposits. The more urgent problem of the constitution
of the blue and red sea-bottom muds may have led mineralogists to overlook this rare
constituent. It is essential to make a careful study of oceanic deposits before removing
the calcium carbonate by digestion with dilute hydrochloric acid, since this treatment
would also remove calcium oxalate.
Although the monoclinic hydrate, CaC,O,.H,0O, the more commonly observed salt
in plants (raphides) (Vesque, 1874) occurs as the mineral whewellite in coal measures
from various localities, the tetragonal salt has not hitherto been observed as a mineral.
H. Braconnat (1825) has indeed recorded a growth of lichen on limestone containing
nearly half by weight of calcium oxalate and J. Liebig (1853) named a similar in-
crustation, thierschite. Neither author, however, gives figures for the water content and
I have not been able to secure a specimen of the original material for identification.
A section of a lichen spore reveals irregularly shaped crystals which, however, prove to
be whewellite not the tetragonal salt. Thierschite should then be regarded as an un-
certain species since the name was given to the material on the basis of an incomplete
chemical analysis. It would also be unwise to give a mineral name to the tetragonal
crystals of hydrated calcium oxalate from the Weddell Sea deposits until the dihydrate
formula is placed beyond question.
The origin of calcium oxalate in the ocean bottom mud of the central Weddell Sea
is entirely conjectural. The writer finds it impossible to suggest how any sedimentary
constituent of the earth’s crust can be restricted to one small region, more particularly
D XIII 9
66 : DISCOVERY REPORTS
when that constituent is widely distributed in small quantities in numerous living
organisms. It is easier, however, to offer reasons for the formation of the tetragonal salt
rather than whewellite in very deep water, given a suitable concentration of calcium
oxalate. Frey has found that the ‘‘envelope”’ crystals are most stable in alkaline solu-
tions containing a high calcium content, and that their stability is also favoured by
immersion in viscous media. H. Wattenburg (1933) has observed the variation of
specific alkalinity with depth of water in the south Atlantic ocean. It is interesting that
his records for many stations show a marked increase in alkalinity between 4000 and
5000 m., corresponding with a slight ‘“‘undersaturation” of calctum carbonate. Hence
the formation of tetragonal calcium oxalate crystals at depths of 4434 to 5008 metres in
the Weddell Sea may be favoured by a similar increase in specific alkalinity of the ocean
bottom water and by the viscosity of the enclosing muds.
GYPSUM, CaSO,.2H,O
The second group of crystals received from Mr Earland consists of two samples from
different stations: St. 428, 66° 57’ S, 11° 13’ W, 2715 fathoms (= 4965 m.), and St. 391,
66° 14'S, 31° 18’ W, 2630 fathoms (= 4809 m.). These are lenticular crystals up to
2°0 X I'O X o°5 mm. in size which are readily shown by optical properties, specific
gravity and chemical tests to be gypsum (Plate II, fig. 2). The crystal forms present are
(111) and (110), only the latter being transparent. The faces (111) are corroded and the
crystals resemble much larger crystals of similar form observed by Baret (1888) and
others from saline deposits. Crystals identical in form but smaller in size have also been
separated from ocean bottom samples brought back by the Discovery Expedition from
the Weddell Sea in 1925. These latter crystals, which were found by Mr E. Heron-Allen,
F.R.S., come from St. WS 553, 63° 33?’ 5S, 60° 333’ W, 5029 m. Gypsum has not hitherto
been recorded from ocean bottom deposits and it is to be noted that this constituent, like
calcium oxalate, would be removed at least partially by initial treatment of the sediments
with acid. Since gypsum is one of the first minerals to be deposited when samples of sea
water are evaporated (J. Usiglio, 1849) its formation in deep-sea deposits is of great
interest. J. H. van’t Hoff (1912) has studied the conditions of formation of gypsum in the
Stassfurt salt deposits. There beds of gypsum, CaSO,.2H,O, and anhydrite, CaSO,,
form the lowest layers. The temperature of transition of gypsum to anhydrite under
ordinary conditions is 63-5° C. The pressure due to 5000 metres of sea-water is about 500
atmospheres and the consequent lowering of the transition temperature about 25° C.
Since the temperature of sea-water at such depths is approximately —2° C. the formation
of calcium sulphate as crystals of gypsum rather than anhydrite is not surprising. The
perplexing fact is that so common a mineral should not be found in other contemporary
ocean-bottom samples ; that indeed its distribution is governed by conditions, as far as we
know, peculiar to the Weddell Sea. A knowledge of these conditions would probably
throw light upon other problems of the Weddell Sea and would form a useful addition
to oceanography (see I. Igelsrud, 1932).
CRYSTALLINE COMPONENTS 67
EARLANDITE, Ca;(C,H,0;),-4H,0
The third group of crystalline constituents differs completely from the calcium
oxalate and gypsum crystals. They were separated from fine and coarse samples from
St. 417, 71° 22'S, 16° 34’ W, 1410 fathoms = 2580 m. consisting chiefly of quartz
grains, foraminifera, etc. The fine samples also contain a moderate number of pale
yellow to white nodules }-1} mm. in diameter, with a warty surface, whilst the coarse
samples yielded some larger nodules up to 2 mm. in diameter and a few fragments up
to 3 mm. across, obviously portions of the crusts of still larger but hollow nodules
(Plate II A, fig. 1). Of particular interest were a nodule attached by siliceous cement
to the wall of a specimen of the foraminifer Rhabdammina linearis, Brady (Plate II A,
fig. 2) and another nodule which had been incorporated with other mineral grains in the
tube of a marine worm. The discovery of these two specimens by Mr Earland places
entirely beyond doubt the fact that this third crystalline component is also of deep-sea
origin and has not resulted from accidental contamination of the sea~-bottom samples.
Both large and small nodules are polycrystalline and very fine-grained < 10-4 mm.
They vary in specific gravity from 1-80 to 1-95 and the aggregate refractive index of
crushed nodules is 1-56. X-ray powder photographs of a nodule of sp. gr. 1:80 and
another of sp. gr. 1-95 are identical (Plate II A, fig. 3) but quite different from powder
photographs of the tetragonal and monoclinic hydrates of calcium oxalate. Nevertheless
the nodules give a definite reaction for calcium, dissolve in dilute acid and decolorize
potassium permanganate solution. ‘They must therefore be composed of a calcium salt
of an organic acid other than oxalic acid. Efforts were then made to establish the
identity of the nodules by comparison with other insoluble calcium salts of organic
acids known to exist in plant cells. Both calcium tartrate and calcium malate have been
recorded as plant constituents (A. Zimmerman, 1892) but powder photographs of both
artificially prepared salts are found to be quite different in pattern from the powder
photograph of the nodules from St. 417. Since citric acid is present in many fruit
juices Mr Hey suggested that calcium citrate, a very insoluble salt, should also be com-
pared. Powder photographs of the artificially prepared salt and the deep-sea nodules
are identical (Plate II A, fig. 3). Moreover, the specific gravity of the artificial salt is
I°951, i.e. identical with the highest observed specific gravity of the nodules and the
ageregate refractive index is the same for both, viz. 1:56. The artificial salt shows a
marked tendency to spherulitic formation, but the individual crystal plates are suf-
ficiently large to yield single crystal X-ray photographs. Since crystallographic and
optical data for calcium citrate are not recorded in the literature we hope to publish
measurements on single crystals at a later date.
By the courtesy of Dr E. Hope the Dyson Perrins laboratory, Oxford, undertook the
microchemical analysis of the deep-sea nodules and obtained the results given in
Table III.
Mr Hey also made residue determinations on two separate samples of nodules
and on artificially prepared calcium citrate. The chemical work confirms the X-ray
9-2
68 DISCOVERY REPORTS
determination and shows that the nodules have a composition close to the theoretical
composition of hydrated calcium citrate, Ca;(C;H;O;),.4H,O. The departures are
probably due to adsorbed water and small variable amounts of impurities. A spectro-
graphic examination of the residue left after ignition of the second sample (4:075 mg.)
studied by Mr Hey shows in addition to calcium, traces of strontium, barium, mag-
nesium, manganese and iron; also minute traces of copper (Plate II A, fig. 4). No
Table III. Chemical analyses of earlandite, Ca;(C,;H;O,),.4H2O, from
St. 417, Weddell Sea, and of artificial calcium citrate
M. H. Hey
Dyson Perrins Artificial
earlandite Theoretical Earlandite calcium
citrate
(OF) 24:01 25°24 = — —
H (%) 3°48 | 3:18 — = =e
CaO (% 28-63 29°48 31-6 29:01 29°70
Material used: mg. 3601 — 1816 4:075 526-2
impurity (except perhaps magnesium) amounts to more than o-o1 per cent, e.g. the
phosphorus (probably present as phosphate) cannot be detected with certainty by
ordinary chemical methods. 'The nature of the small amounts of impurities in the cal-
cium citrate nodules is additional evidence that the nodules were formed at the sea-
bottom (J. V. Samoilov, 1917). Their distribution is even more restricted than calctum
oxalate and gypsum, and their origin is equally conjectural. So far as is known this is
the first reported occurrence of calcium citrate in nature. We therefore propose to name
the new mineral earlandite in recognition of Mr Arthur Earland’s long-continued con-
tributions to the study of ocean deposits.
SUMMARY
Three crystalline components from the ocean bottom of the Weddell Sea have been
identified as crystals of calctum oxalate dihydrate, CaC,O,.2H,O, crystals of gypsum,
CaSQO,.2H,0O, and polycrystalline nodules of calcium citrate, Ca;(C;H;O,),.4H,O, for
which the name earlandite is proposed. X-ray photographs of the deep-sea crystals of
calcium oxalate show that the unit tetragonal cell has dimensions a 12-40, ¢ 7:37 A.
and possesses the symmetry of the space-group Cj, = I 4/m. Crystals from renal calculi
yielding identical X-ray photographs are found to have the probable composition
CaC,O,.2H,O0. Both the deep-sea and renal calculi crystals are identical with, but larger
than “envelope” crystals found in the waste products of many plants and animals. The
trihydrate formula usually given to the “envelope” crystals is incorrect.
69
REFERENCES
Barret, —, 1888. Bull. Soc. Frang. Min., x1, p. 295.
Barker, T. V., 1930. Systematic crystallography. London.
Birp, GOLDING, 1842. Guy’s Hospital Reports, London, vu, p. 175.
Birp, GOLpING, 1843. Urinary Deposits, their Diagnosis, Pathology, and Therapeutical Indications. London.
Birp, GoLp1nc, 1845. London Medical Gazette, 1, p. 49.
Braconnat, Henri, 1825. Annales Chim. Physique, Paris, xxv, p. 318.
Donnay, J. D. H. and MEton, J., 1934. The John Hopkins Univ. Baltimore, U.S.A. Studies in Geol.,
No. 11, p. 328.
Frey, ALBERT, 1925. Vierteljahrsschr. Naturfor. Gesell., Ziirich, Lxx, p. 1.
GranaM, THomas, 1838. Ann. Pharm. (Liebig), Heidelberg, xxv, p. 4.
HEITZMANN, Louis, 1934. Urinary Analysis and Diagnosis by Microscopical and Chemical Examination.
London.
HENDRICKS, STERLING B., 1935. Zeits. Krist., xci, p. 48.
van’t Horr, J. H., 1912. Untersuchungen tiber die Bildungsverhdltnisse der ozeanischen Salzablagerungen
insbesondere des Stassfurten Salzlagers. Leipzig.
IGELsRUD, Iver, 1932. Bull. National Research Council, No. 85, Physics of the Earth. V. Oceanography,
p. 180.
Liesic, Justus, 1853. Ann. Chem. Pharm. (Liebig), Heidelberg, Lxxxv1, p. 113.
SaMoiLoy, J. V., 1917. Min. Mag., xvuir, p. 87.
Scumipt, Cart, 1846. Ann. Chem. Pharm. (Liebig), Heidelberg, x1, p. 288.
Soucuay, A. and Lenssen, E., 1856. Ann. Chem. Pharm. (Liebig), Leipzig and Heidelberg, xcrx, p. 31;
C, p. 308.
UsIcLi0, J., 1849. Annales Chim. Physique, Paris, xxvil, pp. 92 and 172.
VESQUE, —, 1874. C. R. Acad. Sci., Paris, LXXvII, p. 149.
WATTENBERG, HERMANN, 1933. Wassenschaftliche ergebnisse der Deutschen Atlantischen Expedition auf dem
Forschungs- und Vermessungsschiff ‘ Meteor’, 1925-1927, Vill, p. 166. Berlin and Leipzig.
ZACHARIASEN, W. H., 1934. Zeits. Krist., LXXXxIx, p. 442.
ZIMMERMAN, A. W. P., 1892. Die botanische Mikrotechnik. Ein Handbuch der mikroskopischen Prdaparations-,
Reaktions- und Tinktionsmethoden. Lubingen.
INDEX
References to species described in the report are printed in black-faced type; those to synonyms
and text references in roman type. These figures are the serial numbers of the species. Numbers
in italics are page references.
abyssorum, Rhabdammina, 44 catenata, 47
aculeata, Uvigerina, 5 crassatina, 5
acuta, Lagena, 5 limicola, 14
acutauricularis, Cristellaria, 188 aurantiaca, Placopsilinella, 75, 82
acuticosta, Lagena, 125 auriculata, Lagena, 5
adunca, Reophax, 5
agglutinans, Ammobaculites, 75 Bathysiphon, 19-20
agglutinans var. filiformis, Ammobaculites, 76 argillaceus, 20
aknerianus, Cibicides, 212 filiformis, 19
alata, orbignyana var., Lagena, 164 biancae, Lagena, 132
albicans, ‘Thurammina, 34 biformis, Spiroplecta, 5
algaeformis, Rhizammina, 5 Biloculina ringens, 5, 3
alveolata, Lagena, 126 Bolivina, 117
alveolata var. separans, Lagena, 127 cincta, TT
alveolata var. substriata, Lagena, 128 punctata, 117
americanus, Ammobaculites, 77 bradyi, Cribrostomoides, 71
Ammobaculites, 75-80 bradyi, Cyclammina, 15, 102
agglutinans, 75 bradyi, Ehrenbergina, 123
agglutinans var. filiformis, 76 bradyi, Eponides, 220
americanus, 77 bradyi, Gaudryina, ro, 111
foliaceus, 79 bradyi, ‘Trochammina, 93
foliaceus var. recurva, 15, 80 bradyi, Verneuilina, 109
tenuimargo, 78 bradyi var. nitens, Verneuilina, 110
Ammodiscus, 85 bradyi, Virgulina, 116
incertus, 85 brunnensis, Uvigerina, 5
Ammolagena, 83 bucculenta, Miliolina, 5
clavata, 83 bucculenta, var. placentiformis, Miliolina, 5
Ammomarginulina, 75, 81 bulla, Tholosina, 27
ensis, 81 bulloides, Globigerina, 10, 199
Ammosphaeroidina, 96 bulloides, Sphaeroidina, 207
sphaeroidiniformis, 96
anceps, Globotextularia, 5 calomorpha, Nodosaria, 181
angulosa, Uvigerina, 198 canariensis, Globorotalia, 5
angusta, Polymorphina, 195 canariensis, Haplophragmoides, 65, 66
annectens, Lagena, 129 canartensis, Pulvinulina, 5
annulus, Neomeris, IT cancellata, Cyclammina, 98, 99
Anomalina polymorpha, 5 cariosa, Thurammina, 35
antarctica, Textularia, 108 carpenteri, Hormosina, 15, 61
apicularis, Gaudryina, 107 Cassidulina, 118-22
apiculata, Lagena, 130 crassa, 119
arborescens, Pelosina, 5 crassa var. porrecta, 120
arenacea, Miliammina, 104 laevigata, 118
arenaria, Astrorhiza, 14 pacifica, 70, 122
argillaceus, Bathysiphon, 20 subglobosa, 121
Aschemonella, 47 castanea, Thurammina, 31
catenata, 47 catenata, Aschemonella, 47
ramuliformis, 5 catenata, Astrorhiza, 47
scabra, 47 catenata, ‘Textularia, 106
asciformis, Technitella, 5 catenulata, Lagena, 133
aspera, Lagena, 131, 160 charoides, Glomospira, 86
Astrorhiza, 14 Cibicides, 209-13
arenaria, 14 aknerianus, 212
Cibicides (cont.)
lobatulus, 210
pseudoungerianus, 213
refulgens, 209
tenuimargo, 210
wuellerstorfi, 241
cincta, Bolivina, TT
circularis, Miliolina, 8
clavata, Ammolagena, 83
clavata, Lagena, 134
Clavulina, 113
communis, 113
clavulus, Lagena, 135
communis, Clavulina, 113
communis, Nodosaria, 182
concava, Textularia, 5, 107
confusa, Sorosphaera, 5
conglomerata, Globigerina, 203
conica, Textularia, 5, 107
contorta, Cyclammina, 99
contortus, Recurvoides, 69, 74
convergens, Cristellaria, 192
cornuta, Rhabdammina, 5
corrugata, Thurammina, 30
costata, Lagena, 136
crassa, Cassidulina, 119
crassa, Globorotalia, 214
crassa’ var. porrecta, Cassidulina, 120
crassatina, Astrorhiza, 5
crassimargo, Haplophragmoides, 66
crepidula, Cristellaria, 187
Cribrogenerina, 12
Cribrostomoides bradyi, 71
Cristellaria, 187-92
acutauricularis, 188
convergens, 192
crepidula, 187
cultrata, 191
gibba, 190
obtusata, 189
Crithionina, 17-18
granum, 17
mamilla, 18
pisum, var. hispida, 5
cultrata, Cristellaria, 191
curtus, Reophax, 49
cushmani, marginata var., Lagena, 159
Cyclammina, 98-102
bradyi, 15, 102
cancellata, 98, 99
contorta, 99
orbicularis, 15, 100
pusilla, 101
cylindrica, Marsipella, 43
cylindrica, Pelosina, 16
cylindroides, Polymorphina, 194
Cystammina, 97
pauciloculata, 97
Dactylopora, Ir
deformis, Gaudryina, 75, 112
INDEX
Delosina, 15, 114
wiesneri, 15, 114
dentaliniformis, Reophax, 52
depressa, Pyrgo, 1
depressa, Sorosphaera, 21
desmophora, Lagena, 10, 137
difflugiformis, Proteonina, 25
Discorbis, 208
globularis, 208
discreta, Rhabdammina, 45
distans, Reophax, 57
dubia, Globigerina, 5, 203
dutemplei, Truncatulina, 5
dutertrei, Globigerina, 202
eccentrica, stelligera var., Lagena, 10, 176
echinata, Fissurina, 160
echinata, marginata var., Lagena, 160
Ehrenbergina, 123-4
bradyi, 123
hystrix var. glabra, 124
pupa, 5
serrata, 5, 123
elegans, Epistomina, 5
elegans, Pulvinulina, 5
elongata, Hyperammina, 40
Elphidium, 228
excavatum, 228
emaciata, globosa var., Lagena, 145
ensis, Ammomarginulina, 81
Epistomina elegans, 5
Eponides, 215-20
bradyi, 220
exiguus, 218
karsteni, 216, 217
tumidulus, 219
umbonatus, 215
weddellensis, 217
excavatum, Elphidium, 228
exiguus, Eponides, 218
exsculpta, Lagena, 138
extensa, Polymorphina, 20, 197
favosa, Thurammina, 33
favosa, papillata var., ‘Thurammina, 33
favosa, reticulata var., Thurammina, 5, 30
feildeniana, Lagena, 5
felsinea, Lagena, 139
filiformis, agglutinans var., Ammobaculites, 76
filiformis, Bathysiphon, 19
filiformis, Gaudryina, 107
filiformis, Spiroplectammina, 75, 105
fimbriata var. occlusa, Lagena, 10, 140
Fissurina echinata, 160
flexibilis, Hippocrepina, 38
foliaceus, Ammobaculites, 79
foliaceus var. recurva, Ammobaculites, 15, 80
formosa, Lagena, 141
foveolata, Lagena, 142
foveolata var. paradoxa, Lagena, 10, 143
friabilis, Hyperammina, 16, 39
72, DISCOVERY REPORTS
fusca, Psammosphaera, 22, 2 Hippocrepina, 38
fusiformis, Reophax, 51 flexibilis, 38
hispida, pisum var., Crithionina, 5
Gaudryina, 1§1—-12 hispida, Lagena, 150, 160
apicularis, 107 hispidula, Lagena, 151
bradyi, 20, 111 Hormosina, 59-64
deformis, 75, 112 carpenteri, 5, 61
pseudofiliformis, 5, 107 globulifera, 59
gaussi, Vanhoeffenella, 15 irregularts, 5
gibba, Cristellaria, 190 lapidigera, 75, 64
gibba, Polymorphina, 5 normani, 60
glabra, hystrix var., Ehrenbergina, 124 ovicula, 75, 62
glabra, Marginulina, 186 ovicula var. gracilis, 63
Glandulina, 193 Hyperammina, 39-41
laevigata, 193 elongata, 40
Globigerina, 199-204 friabilis, 16, 39
bulloides, 70, 199 laevigata, 40A
conglomerata, 203 subnodosa, 5
dubia, 5, 203 tubulosa, 15, 41
dutertrei, 202 hystrix var. glabra, Ehrenbergina, 124
inflata, 201
pachyderma, 204 incertus, Ammodiscus, 85
triloba, 200 inconspicua, ‘T'rochammina, 15, 95
globigeriniformis, ‘Trochammina, 94, 95 indivisa, Rhizammina, 5
Globorotalia, 214 inflata, Globigerina, 201
canariensts, 5 inflata, 'rochammina, 89
crassa, 214 iridea, Nonionella, 227
truncatulinoides, 5 irregularis, Hormosina, 5
globosa, Lagena, 144 irwinensis, Nodosaria, 12
globosa var. emaciata, Lagena, 145
globosa var. setosa, Lagena, 146, 152, 157 Jaculella, 37
Globotextularia anceps, 5 obtusa, 15, 37
globularis, Discorbis, 208
globulifera, Hormosina, 59 karsteni, Eponides, 216, 217
glomeratus, Haplophragmoides, 72 Keramosphaera, 13
Glomospira, 86~7 murrayl, 13
charoides, 87
gordialis, 86 labiosa, Miliolina, 9
gordialis, Glomospira, 86 laevigata, Cassidulina, 118
gracilis, ovicula var., Hormosina, 63 laevigata, Glandulina, 193
gracilis, Lagena, 147 laevis, Lagena, 152
gracillima, Lagena, 148 Lagena!, 125-80
granum, Crithionina, 17 acuta, 5
alata, orbignyana var., 164
haeusleri, Thurammina, 32 aspera, 160
Haplophragmoides, 65-73 auriculata, 5
canariensis, 65, 66 desmophora, 10
crassimargo, 66 eccentrica, stelligera var., IO
glomeratus, 72 echinata (Fissurina), 160
nitidus, 70 feildeniana, 5
rotulatus, 73 fimbriata var. occlusa, 10
scitulus, 69, 74 foveolata var. paradoxa, 10
sphaeriloculus, 75, 67 globosa var. setosa, 152, 157
subglobosus, 71 hispida, 160
trullissatus, 68, 102 laevigata, 132
umbilicatum, 5, 66 lagenoides, 135
weddellensis, 75, 66 lamellata, TO, 155
hemisphaerica, Webbinella, 5 marginata, 160
hexagona, Lagena, 149 multicosta, 5
’ As the species of Lagena dealt with in the report are printed alphabetically, it is unnecessary to list them
here. They are indexed elsewhere under specific and varietal names.
Lagena (cont.)
orbignyana var. alata, 164
quadrilatera, IO
quinquelatera, 5
semistriata, 5
setosa, globosa var., 152, 157
sidebottomt, TO
stelligera var. eccentrica, TO
torquata, 5
lagenoides, Lagena, 153
lagenoides var. tenuistriata, Lagena, 154
lamellata, Lagena, ro, 155
lapidigera, Hormosina, 15, 64
Laticarinina, 221
pauperata, 221
limbata, Spiroloculina, 5
limicola, Astrorhiza, 14
linearis, Rhabdammina, 46
lineata, Lagena, 156
Lituola, Moniliform, 61
lobatulus, Cibicides, 210
longiscatiformis, Reophax, 54
longispina, Lagena, 157
malovensis, T'rochammina, 90
mamilla, Crithionina, 18
marginata, Lagena, 158, 160
marginata var. cushmani, Lagena, 159
marginata var. echinata, Lagena, 160
marginata var. raricostata, Lagena, 161
marginata var. semimarginata, Lagena, 162
marginata var. spinifera, Lagena, 163
Marginulina, 186
glabra, 186
Marsipella, 43
cylindrica, 43
membranaceum, Nodellum, 58
micaceus, Reophax, 55
Miliammina, 10, 15, 104
arenacea, 104
Miliolina, 4-9
bucculenta, 5
bucculenta var. placentiformis, 5
circularis, 8
labiosa, 9
oblonga, 4
pygmaea, §
tricarinata, 7
venusta, 6
minuta, Syringammuna, 5
Moniliform Lituola, 61
Monogenerina, 12
texana, I2
mucronata, Nodosaria, 183
multicosta, Lagena, 5
murrayi, Keramosphaera, 13
murrhyna, Pyrgo, 2
nana, Trochammina, 91
Neomeris annulus, TT
nitens, bradyi var., Verneuilina, 110
INDEX
nitidus, Haplophragmoides, 70
Nodellum, 58
membranaceum, §8
Nodosaria, 181-5
calomorpha, 181
communis, 182
irwinensis, 2
mucronata, 183
pauperata, 184
perversa, 5
raphanistrum var., 10, 15, 185
roemerl, 5
striato-clavata, 12
Nodosinella, 12
nodulosus, Reophax, 56
Nonion, 224-6
pompilioides, 224
scapha, 226, 227
stelliger, 225
umbilicatulus, 5
Nonionella, 226, 227
iridea, 226, 227
normani, Hormosina, 60
obesa, Sigmoilina, 10
obliquiloculata, Pullenia, 5
oblonga, Miliolina, 4
obtusa, Jaculella, 75, 37
obtusata, Cristellaria, 189
occlusa, fimbriata var., Lagena, 70, 140
orbicularis, Cyclammina, 15, 100
orbicularis, Rotalia, 222
orbignyana, Lagena, 164
orbignyana var. alata, Lagena, 164
orbignyana var. walleriana, Lagena, 165
Orbitolites, 24
ovicula, Hormosina, 15, 62
ovicula var. gracilis, Hormosina, 63
pachyderma, Globigerina, 204
pacifica, Cassidulina, 10, 122
palliolata, Lagena, 166
papillata, Thurammina, 29
paradoxa, foveolata var., Lagena, 10, 143
parva, Psammosphaera, 23
pauciloculata, Cystammina, 97
pauperata, Laticarinina, 221
pauperata, Nodosaria, 184
Pelosina, 16
arborescens, 5
cylindrica, 16
perversa, Nodosaria, 5
pilulifer, Reophax, 50
pisum var. hispida, Crithionina, 5
placentiformis, bucculenta var., Miliolina, :
Placopsilinella, 15, 82
aurantiaca, 15, 82
polymorpha, Anomalina, 5
Polymorphina, 194-7
angusta, 195
cylindroides, 194
2)
73
74 DISCOVERY REPORTS
Polymorphina (cont.) reticulata, favosa var., Thurammina, 5, 30
extensa, IO, 197 Rhabdammina, 27, 44-6
gibba, 5 abyssorum, 44
problema, 196 cornuta, 5
pompilioides, Nonion, 224 discreta, 45
porrecta, crassa var., Cassidulina, 120 linearis, 46
problema, Polymorphina, 196 Rhapidionina, 12
protea, Thurammina, 15, 36 Rhizammina,
Proteonina, 25-6 algaeformis, 5
difflugiformis, 25 indivisa, 5
tubulata, 26 ringens, Biloculina, 5, 3
Psammosphaera, 22-3, 36, 69 rizzae, Lagena, 168
fusca, 22, 24 vobustus, Reophax, 5
parva, 23 roemert, Nodosaria, 5
pseudofiliformis, Gaudryina, 5 rossensis, T'rochammina, 92
pseudoungerianus, Cibicides, 213 Rotalia, 222-3
Pullenia, 205-6 orbicularis, 222
obliquiloculata, 5 soldanil, 92, 223
quinqueloba, 206 rotulatus, Haplophragmoides, 73
sphaeroides, 205
subcarinata, 206 Saccammina, 24
Pulvinulina, socialis, 5
canariensis, 5 sphaerica, 24
elegans, 5 Saccorhiza, 42
truncatulinoides, 5 ramosa, 42
punctata, Bolivina, 117 scabra, Aschemonella, 47
pupa, Ehrenbergina, 5 scapha, Nonion, 226, 227
pusilla, Cyclammina, ror schlichti, Lagena, 169
pygmaea, Miliolina, 5 schreibersiana, Virgulina, 115
pygmaea, Truncatulina, 220 scitulus, Haplophragmoides, 69, 74.
Pyrgo, 1-3 scorpiurus, Reophax, 48
depressa, I seguenziana, Lagena, 170
murrhyna, 2 semilineata, Lagena, 171
vespertilio, 3 semimarginata, marginata var., Lagena, 162
semistriata, Lagena, 5
quadrilatera, Lagena, ro, 167 separans, alveolata var., Lagena, 127
quinquelatera, Lagena, 5 serrata, Ehrenbergina, 5, 123
quinqueloba, Pullenia, 206 setosa, globosa var., Lagena, 146, 152, 157
sidebottomi, Lagena, 70, 172
ramosa, Saccorhiza, 42 sigmoidea, Sigmoilina, 12
ramuliformis, Aschemonella, 5 Sigmoilina, 10-12
raphanistrum, var., Nodosaria, 10, 15, 185 obesa, 10
raphanus, Technitella, 5 sigmoidea, 12
raricostata, marginata var., Lagena, 161 tenuis, II
recurva, foliaceus var., Ammobaculites, 15, 80 socialis, Saccammina, 5
Recurvoides, 75, 74 soldani, Rotalia, 92, 223
contortus, 69, 74 soldanii, Trochammina, 92
refulgens, Cibicides, 209 Sorosphaera, 21
Reophax, 25, 48-57 confusa, 5
adunca, 5 depressa, 21
curtus, 49 Spandelina, 12
dentaliniformis, 52 striatella, 12
distans, 57 Spandelinoides, 12
fusiformis, 51 sphaerica, Saccammina, 24
longiscatiformis, 54 sphaeriloculus, Haplophragmoides, 75, 67
micaceus, 55 sphaeroides, Pullenia, 205
nodulosus, 56 Sphaeroidina, 207
pilulifer, 50 bulloides, 207
robustus, 5 sphaeroidiniformis, Ammosphaeroidina, 96
scorpiurus, 48 spiculifer, Reophax, 53
spiculifer, 53 spinifera, marginata var., Lagena, 163
Spirolocammina, I5, 103
tenuis, I5, 103
Spiroloculina,
limbata, 5
tenuis, II
Spiroplecta,
biformis, 5
Spiroplectammina, 15, 105
filiformis, 75, 105
squamata, T'rochammina, 88
squamosa, Lagena, 173
staphyllearia, Lagena, 174
stelliger, Nonion, 225
stelligera, Lagena, 175
stelligera var. eccentrica, Lagena, 10, 176
stewarti, Lagena, 177
striata, Lagena, 178
striato-clavata, Nodosaria, I2
subcarinata, Pullenia, 206
subglobosa, Cassidulina, 121
subglobosus, Haplophragmoides, 71
subnodosa, Hyperammina, 5
substriata, alveolata var., Lagena, 128
sulcata, Lagena, 179
Syringammina minuta, 5
Technitella, 5
asciformis, 5
raphanus, 5
tenera, Truncatulina, 215
tenuimargo, Ammobaculites, 78
tenuimargo, Cibicides, 210
tenuimargo, Truncatulina, 5, 210
tenuis, Sigmoilina, 14
tenuis, Spirolocammina, 15, 103
tenuis, Spiroloculina, 11
tenuissima, Textularia, 15, 107
tenuistriata, lagenoides var., Lagena, 154
Textularia, 106-8
antarctica, 108
catenata, 106
concava, 5, 107
conica, 5, 107
tenuissima, 15, 107
Tholosina, 27-8
bulla, 27
vesicularis, 28
Thurammina, 29-36
albicans, 34
cariosa, 35
castanea, 31
corrugata, 30
favosa, 33, 30
favosa var. reticulata, 5, 30
haeusleri, 32
papillata, 29, 30
papillata var. favosa, 33
protea, 15, 36
Tolypammina, 84
vagans, 84
INDEX 75
torquata, Lagena, 5
tricarinata, Miliolina, 7
triloba, Globigerina, 200
Trochammina, 88-95
bradyi, 93
globigeriniformis, 94, 95
inconspicua, I5, 95
inflata, 89
malovensis, 90
nana, 91
rossensis, 92
soldanii, 92
squamata, 88
trullissata, 102
turbinata, 5, 74
trullissata, Trochammina, 102
trullissatus, Haplophragmoides, 68, 102
Truncatulina,
dutemplet, 5
pygmaea, 220
tenera, 215
tenuimargo, 5, 210
ungeriana, 213
truncatulinoides, Globorotalia, 5
truncatulinoides, Pulvinulina, 5
tubulata, Proteonina, 26
tubulosa, Hyperammina, 15, 41
tumidulus, Eponides, 219
turbinata, Trochammina, 5, 74.
umbilicatulus, Nonion, 5
umbilicatum, Haplophragmoides, 5, 66
umbonatus, Eponides, 215
ungeriana, Truncatulina, 213
Uvigerina, 198
aculeata, 5
angulosa, 198
brunnensis, 5
vagans, Tolypammina, 84
Vanhoeffenella, 15
gaussi, 15
ventricosa, Lagena, 180
venusta, Miliolina, 6
Verneuilina, 109-10
bradyi, 109
bradyi var. nitens, 110
vesicularis, Tholosina, 28
vespertilio, Pyrgo, 3
Virgulina, 115-16
bradyi, 116
schreibersiana, 115
walleriana, orbignyana var., Lagena, 165
Webbinella hemisphaerica, 5
weddellensis, Eponides, 217
weddellensis, Haplophragmoides, 15, 66
wiesneri, Delosina, 15, 114
wuellerstorfi, Cibicides, 211
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PLATE I
Fig. 1. Pelosina cylindrica, Brady (No. 16): x 4. (The drawing is reversed, the base being at
the top.)
Figs. 2-4. Sigmoilina obesa, Heron-Allen and Earland (No. 10): x 26. Figs. 2, 3, side views.
Fig. 4, oral end view.
Fig. 5. Vanhoeffenella gaussi, Rhumbler (No. 15): x 26.
Fig. 6. Proteonina tubulata (Rhumbler) (No. 26): x 26.
Figs. 7-9. Keramosphaera murrayi, Brady (No. 13). Fig. 7, general view: x 26. Fig. 8,
a broken specimen showing roughly concentric layers: x 26. Fig. 9, a portion of the
unworn external surface showing apertures of the tubular chamberlets: x 50.
Figs. 10, 11. Thurammina corrugata, sp.n. (No. 30). Fig. 10, a broken specimen reconstructed
from fragments showing internal and external surfaces: x 26. Fig. 11, a young and
unbroken individual: x 45.
Figs. 12, 13. Thurammina cariosa, Flint (No. 35): x 26. Fig. 12, an individual specimen.
Fig. 13, a double specimen.
Fig. 14. Thurammina favosa, Flint (No. 33): x 26. Sessile on sand grain.
Figs. 15, 16. Haplophragmoides weddellensis, sp.n. (No. 66): x26. Fig. 15, side view.
Fig. 16, edge-oral view.
Figs. 17, 18. Haplophragmoides sphaeriloculus, Cushman (No. 67): x 26. Fig. 17, side view.
Fig. 18, edge-oral view.
Fig. 19. Hormosina normani, Brady (No. 60): x 6.
Figs. 20-22. Recurvoides contortus, Earland (No. 74): x 45. Figs. 20, 21, side views. Fig. 22,
edge-oral view.
Figs. 23, 24. Ammobaculites agglutinans (d’Orbigny) (No. 75): x 26. Side views.
Figs. 25, 26. Cyclammina pusilla, Brady (No. 101): x 26. Fig. 25, edge-oral view. Fig. 26,
side view.
Figs. 27, 28. Cyclammina orbicularis, Brady (No. 100): x 18. Fig. 27, edge-oral view. Fig. 28,
side view.
Figs. 29-31. Cyclammina contorta, Pearcey (?) (No. 99). Fig. 29, side-oral view: x 26.
Fig. 30, side view: x26. Fig. 31, side view: x15. All three specimens more or less
worn and showing cancellated structure.
Figs. 32-34. Trochammina soldanii, sp.n. (No. 92): x 26. Fig. 32, edge view. Fig. 33, dorsal
surface. Fig. 34, ventral surface.
Figs. 35-37. Spirolocammina tenuis, Earland (No. 103): xX 45. Side views.
Figs. 38-40. Miliammina arenacea (Chapman) (No. 104): x 45. Fig. 38, front view. Fig. 39,
rear view. Fig. 40, oral-end view.
Figs. 41, 42. Lagena alveolata, Brady, var. separans, Sidebottom (No. 127): X45. Fig. 41,
side view. Fig. 42, edge view.
Figs. 43, 44. Lagena alveolata, Brady, var. substriata, Brady (No. 128): x 45. Fig. 43, edge
view. Fig. 44, side view.
Fig. 45. Lagena clavulus, Heron-Allen and Earland (?) (No. 135): x70.
Fig. 46. Lagena desmophora, Rymer Jones (No. 137): X70.
Fig. 47. Lagena laevis (Montagu) (No. 152): x70. Variety with basal spines.
Figs. 48-50. Lagena lamellata, Sidebottom (No. 155). Fig. 48, specimen with outer layer
almost entirely denuded, showing inner spinous layer: x70. Fig. 49, specimen with
outer layer almost intact: x 70. Fig. 50, a fragment of the outer layer of plates supported
on minute spines: x 7o.
Figs. 51-53. Lagena marginata (Walker and Boys) var. echinata (Seguenza) (No. 160): x 70.
Figs. 51, 52, side views. Fig. 53, edge view.
Figs. 54, 55. Lagena orbignyana (Seguenza) (No. 164): x45. Fig. 54, edge view. Fig. 55,
side view.
Figs. 56-59. Lagena orbignyana (Seguenza) var. walleriana, J. Wright, var. (No. 165): x70.
Fig. 56, side view. Fig. 57, edge view. Fig. 59, basal view. Fig. 58, oral end view of
a trigonal specimen.
Figs. 60, 61. Lagena orbignyana (Seguenza) var. cf. alata, Cushman (No. 164): x 45. Fig. 60,
side view. Fig. 61, edge view.
Fig. 62. Lagena stelligera, Brady var. (No. 175): X70.
Figs. 63, 64. Lagena stelligera, Brady, var. eccentrica, Sidebottom (No. 176): x 45. Fig. 64,
variety with basal spine.
Figs. 65-67. Eponides weddellensis, sp.n. (No. 217): X95. Fig. 65, edge-oral view. Fig. 66,
ventral view. Fig. 67, dorsal view.
RAE
VOL. Xill
DISCOVERY REPORTS,
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PLATE II
Fig. 1. Envelope-shaped crystals of hydrated calcium oxalate, CaC,O,.
2H,O, from the Weddell Sea (‘Scotia’, St. 286, 4550 m.). x15.
Fig. 2. Lenticular crystals of gypsum, CaSO,.2H,O, from the Weddell
Sea (‘Scotia’, St. 391, 4809 m.). x 10.
Figs. 3 and 4. X-ray photographs of a crystal of hydrated calcium
oxalate from the Weddell Sea. Both photographs were taken with un-
filtered copper radiation and with the same cylindrical camera diameter
6-04cm. A length of 8-5 cm. on the original films is equal to 10 cm. on
the reproduced figures. Fig. 3 shows the photograph obtained when the
crystal is rotated about the [100] axis. Fig. 4 is the corresponding photo-
graph for the [oo1] axis.
DISCOVERY, REPORTS, VOL. Xai PEATE U1
CRYSTALS FROM WEDDELL SEA DEPOSITS
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PLATE IIa
Fig. 1. Nodules of earlandite, Ca,(C,H;O,)..4H,O, from the Weddell
Sea (‘Scotia’, St. 417, 2580 m.). x8.
Fig. 2. Nodules of earlandite attached by siliceous cement to the wall
of Rhabdammina linearis, Brady. x 14.
Fig. 3. X-ray powder photograph of a nodule of earlandite, taken with
unfiltered copper radiation and with a cylindrical camera, diameter
6-04 cm. A length of 10 cm. on the original film is equal to 10 cm. on
the reproduced figure.
Fig. 4. Portion of the spectrographic record from wave-lengths 4200-
6000 A. A quartz spectrograph fitted with a Hartmann diaphragm was
used giving accurately aligned spectra of: A, carbon arc alone; B, R.U.
powder; C, residue left after ignition of 4:075 mg. earlandite (see
Table III). R.U. (Raies Ultimes) powder consists of small quantities
of fifty-one elements diluted so that only the ‘Raies Ultimes’ (i.e. the
most important or sensitive lines) appear in the electric arc.
DISCOVERY REPORTS, VOL. XIII PIPATE TRA
6,000 5,000 4,500 A
B
|
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SoS “ 7 oS
CRYSTALS FROM WEDDELL SEA DEPOSITS
Y eh nae
OVERY —
ORTS "6
"Vol. XIII, pp. 77-106, olites 1X1 noes
Saag CE
Hoy > Bana te te Diseagios Committee, Colonial Office, London
on ee of the poe of the Dependencies of the Falkland Islands
[HE ROYAL RESEARCH SHIP:
‘DISCOVERY ID
RAL. Ardley, RNR.
Be nd ee
N. A. Mackintosh, D.Sc.
Poe ie |
oS ee 2
oval muses
‘Sty hig “ip
CAMBRIDGE
“AT THE UNIVERSITY PRESS
1936
Price nine shillings net
[Discovery Reports. Vol. XIIT, pp. 77-106, Plates III-X III, July, 1936]
tHE ROYAR RESEARCH SHLP
“DISCOVERY LL’
By
Rep Ace barAtR Dab YR NERS
AND
N. A. MACKINTOSH, D.Sc.
CONG ENS
Iiotixorvoho(eatoyne Go a, ice | Ce OEem Soe nOuum GC oNmoM 5) G0 “o, o o Lp? 47)
(Contimneuion amelclastin 5 6 6 6 6 6 6 © 6 56 © 90 JG 6 ¢ 80
Arrangement of fittings and accommodation . . . . ... «. 81
Roredecks-2 Vy toere sms cas is 7a. Pos. Ree one amen mE 83
Waboratoriesandideckshouses:amidships)..) -.)-)) u-n- s-necne 83
Aviterideck.g pe gtct Mae fore ENT oc. G. U.5m Disney ana aera am 85
Boat.deck= freee ere Tide nc «| cee Sco Ae Cn me 86
INewatenntaye cinaliahyiye lxalyes 5 5 5 be bp oo dG 9 6 4 6 « 87
NMainideckset..) cancer ee hrs Sos” dee 88
raleaioepgaom “eH bd 09 o of Gig won Ode Go 2 « 89
Special accommodation for research penis: <3: amy once! Wee 2 ne 92
Biological and hydrological laboratories . . . . . . . .. . 92
Roughwlaboratorys 0 o- 5 5) een ee ae 96
oo MNT Hs 5 6 o & 6 © 9 6 @ 0 & & p = 96
Scientific instrument store and workshop . . . . .. .. . 97
INetistore? } a0 2. i> ee ee te oe ee cn Boe 97
Scientific equipment ... . es ca Omecee Ly cy Ys) Se 98
Deck céati~ Sis 3 yk eee so ge) Poe re eo eier ey se 98
Appatattis-, %i2 0s) ic: roa iite et ncghuciete tcl acti: Mehmet s ETO
SolbehiyrtdheS 5 56 6 o o@ 6 o o 6 o 6 5 5 8 TOR
ILAlyoehonyONNOES § c ao @ 6 o © a Gg o © © 6 o © 6 DOL
eres SGUIE SS 5 5 Gg o 696 «6 6 0 6 0 0 jfalleminoiane ie
is
THE ROYALARESEARCH SHIP “DISCOVERY Ii
By R. A. B. Ardley, R.N.R., and N. A. Mackintosh, D.Sc.
(Plates III-XIII; Text-figures 1-5)
INTRODUCTION
HE R.R.S. ‘Discovery’, of which an account appeared in Vol. I of the Discovery
Reports, returned to England in October 1927, at the end of her first commission.
It was originally intended that she should sail south again to continue her investigations
in regions where a steel ship would not be suitable. Before definite plans were made,
however, it became known that a wooden ship would be needed for the British Aus-
tralian New Zealand Antarctic Expedition under Sir Douglas Mawson, and in 1928 the
Australian Government came forward with a proposal to charter the * Discovery’ for
this purpose. The experience gained during her employment by the Discovery Com-
mittee had shown that the researches which it was most important to prosecute as the
next stage of the investigations lay in the open ocean. They could be carried out far
more expeditiously in a ship of greater speed and range of action, and did not call for
the unique strength of hull which rendered the ‘ Discovery’ so suitable for the coastal
exploration to be undertaken by Sir Douglas Mawson.
The Discovery Committee, in view of these considerations, accepted the Australian
offer and obtained sanction from the Secretary of State for the Colonies for the con-
struction of a new ship with greater speed and cruising radius. Since encounter with ice
would only be incidental to the continuation of the ship’s work, it was decided that a
steel ship would be preferable to a wooden one, being more economical and allowing
better accommodation. Experience gained by the whaling factories in recent years had
shown that it was practicable for a strengthened steel ship to penetrate light Antarctic
pack-ice. With a full-powered steam vessel observations over a wide area could be
carried out more efficiently, as full advantage could be taken of weather suitable for the
operations, and better accommodation provided for the scientific work. Strengthening
of the hull was provided to increase the safety of the ship in any pack-ice necessarily
met with in the course of her work.
The ship, which has been named ‘ Discovery II’, was specially designed for the work
in prospect. She is a single-screw steamship of 1036 tons gross (displacement 2100 tons
at a draught of just under 17$ feet), with triple expansion engines developing sufficient
power to give a maximum speed of 13} knots on trials and an economic speed of
10 knots. The following special features are embodied in her design:
(i) Closely spaced frames forward, and double plating of the bow down to the forefoot
and along the water-line, with wood panting stringer and ice compression beams in the
forehold.
I-2
AUG 8 1936
80 ; DISCOVERY REPORTS
(ii) Large bunker capacity for fuel oil, allowing a cruising range or endurance of
about 8000 miles at full speed and some 10,000 miles at economic speed.
(iii) Auxiliary deck machinery specially designed for various branches of scientific
research.
(iv) In the accommodation—a biological and a physical and chemical laboratory, a
laboratory for simple and rough work, a dark room and various storerooms for scientific
gear, all these being specially adapted for the work.
The vessel has a complement of fifty-two when carrying a scientific staff of six.
The ‘Discovery II’ first sailed for the Antarctic in December 1929, and since then
has been continuously employed in the investigations undertaken by the Discovery
Committee. The first commission lasted from 1929 to 1931, during which period her
work was mainly in the waters of the Dependencies of the Falkland Islands and in the
South Atlantic sector of the Antarctic. During her second commission (1931-3) her
voyages included a complete circumnavigation of the Antarctic continent, in the course
of which W- or V-shaped cruises, between the ice-edge and warmer waters, were carried
across the southern parts of the Indian, Pacific and Atlantic Oceans. Voyages in the
third commission (1933-5) were mainly in the Atlantic and Pacific sectors of the Ant-
arctic, and included several long zig-zag cruises in the vicinity of the pack-ice. Recently
the ship sailed again on her fourth commission.
Throughout these years the ‘Discovery II’ has been found admirably suited to the
work for which she was designed. Encounters with the most adverse weather conditions
have proved her to be thoroughly seaworthy, and in facilities for the scientific work she
has risen to all expectations.
The account of the vessel which follows owes much, particularly in the sections deal-
ing with construction, to a very careful revision undertaken by the late Mr A. Harker,
of Messrs Flannery, Baggallay and Johnson, Ltd., shortly before his untimely death.
CONSTRUCTION AND DESIGN
The plans and specifications of the ship, her machinery and equipment were drawn
up by Messrs Flannery, Baggallay and Johnson, Ltd., acting under the instructions of
the Crown Agents for the Colonies, and the contract for her building was placed on
February 6, 1929, with Messrs Ferguson Brothers, of Newark Works, Port Glasgow,
who submitted the most favourable tender. The ship was launched on November 2,
1929, with steam up, practically ready for trials.
The principal dimensions of the vessel are:
Length, overall be me 2QAatG:
Length at load water-line_ ... 220 ft.
Breadth, moulded _... ae 26cft:
Depth, moulded se = 20 ft.
Load draught, designed mean 16 ft.
Load draught, Lloyd’s summer
freeboard ... sue ee 7 ete
R.R.S. “DISCOVERY II’ 81
The appearance and design of the ship are illustrated in Plates I-III. She is of flush
deck type (the upper deck being the strength deck) with a raised forecastle and half
poop. She has a straight stem down to about 1 ft. above the load water-line, where the
stem runs away in a long fair curve to the keel. This cut-away forefoot improves her
steering qualities and is of assistance in breaking light pack-ice. In section the stem is
rabeted or T-shaped, affording protection to the edges of the plates in ice navigation.
The fore body of the ship is well flared out from the water-line to the gunwale for about
40 ft. aft from the stem (i.e. to the end of the topgallant forecastle), this form being
intended to guard against the shipping of heavy water when working in a head sea. The
ship, in fact, has proved herself remarkably dry for her size when hove-to. The form of the
hull is rather fine. The ship has a good rise of floor, and a round bilge with a very slight
tumble-home from the load water-line to the upper deck—a large tumble-home would
have been inconvenient in handling scientific gear.
The stern is of the ordinary elliptical counter type, which is well adapted for shooting
large nets, and in conjunction with the raised poop has proved its seaworthy qualities
when running before sea and wind. The main strength members of the ship’s hull are
of specially heavy construction, the stem, keel and sternpost all being well in excess of
classification requirements for vessels navigating in ice. In addition to this strong
framework, the frames in the fore body of the ship are closely spaced and very deep, and
a series of cross-beams consisting of pitch pine timbers of 12 by 12 in. section are fitted
at frequent intervals extending aft for about 50 ft. from the stem. ‘The ends of the beams
are housed in a pitch pine panting stringer about 7 ft. below the main deck. The com-
bination of stringer and beams at normal water-line affords a valuable resistance against
ice. The other main ice protection is formed by a doubling of the shell plating fore and
aft along the water-line and all round the bow to the height of the upper deck. The
beams to the upper deck are fitted on every frame to increase the rigidity of the structure.
The rudder is of large area and heavy construction, much in excess of classification
requirements; it proved to be very effective, for the ship carries her steerage way under
ordinary conditions until she is practically stopped. Six transverse bulkheads are fitted,
two oiltight and four watertight. The main deck is of pitch pine; the upper deck is of
steel, sheathed with 2}-in. pitch pine, and both bridge decks are of teak. Bilge keels are
fitted amidships for about one-third of the vessel’s length. They are constructed of
T-bar and bulb plate, so arranged that in the event of the projecting bulb plate being
damaged it will become detached from the T-bar with the minimum risk of damaging
the ship’s plating.
ARRANGEMENT OF FITTINGS AND ACCOMMODATION (Plates III-V)
The whole of the upper deck is protected by bulwarks 3 ft. 6 in. high, capped with a
teak rail and provided with wash-ports to allow free outlet for any water shipped. ‘Two
hinged doors in the bulwarks, one on each side, are fitted in the waist to form gangways
for the accommodation ladder.
82 DISCOVERY REPORTS
All the davits and small winches for operating scientific gear are placed along the port
side of the ship, and all refuse outlets and discharges are led, so far as practicable, to the
starboard side to prevent rubbish from fouling the nets.
On the topgallant forecastle, at the stem head, there is a pedestal for seating a 20-in.
searchlight, an alternative position for the searchlight being provided on a steel plat-
form fitted at the foot of the fore topmast just beneath the crow’s nest. Recently the
20-in. searchlight has been superseded by twin 10-in. Admiralty searchlights mounted
on the navigating bridge. Twelve feet abaft the stem on the port side of the forecastle
is the Lucas sounding machine, driven by a three-cylinder Brotherhood steam engine.
This position was found to be satisfactory, as it is sufficiently far removed from the
after machine to allow nets to be worked during sounding operations without danger of
the wires from the two machines becoming foul. On the starboard side, level with the
Lucas machine, is a light harpoon gun, with which some of the smaller species of whale
can be captured. It is a small gun, mounted on a swivel and firing larger harpoons than
could be carried in a shoulder gun. Just forward of the break of the forecastle is the
deep hydrological reel and davit (Plate X, fig. 2), used entirely for obtaining tempera-
tures and water samples from depths below 500 m. A full description of these fittings
is given below in the section on equipment. The usual bollards and fairleads are pro-
vided, and a capstan, worked by a vertical spindle from the windlass below deck, occupies
the centre of the forecastle, with a telegraph and speaking tube for communication with
the windlass operator. Controls are also provided on the forecastle deck for handling
the windlass and capstan. A stout breakwater, V-shaped in plan, and lightly canted
forward from its base, is fitted near the after end of the forecastle head: this throws off
much of the water shipped over the bows. Abaft this are carried two mooring wire reels,
and the spare bower anchor. The forestay is provided with hanks and carries a large
fore staysail.
Beneath the forecastle head, right forward, is a small ready-use deck store. The centre
of the space in the forecastle is taken up by the windlass, which is of heavy construction
and was made to special design by Messrs Clarke, Chapman and Co., Ltd. It is used
for working the anchors and cables, which are considerably larger than Lloyds’ require-
ments for the size and service of the ship. The upper end of the hawse pipes open on
deck just abaft the bulkhead of the deck store, and patent cable stoppers are fitted be-
tween the hawse pipes and the windlass. Abreast the windlass on the starboard side
is a paint locker, with the crew’s washhouse abaft it. Next to the washhouse are the
crew’s lavatories, entered direct from the upper deck and having no communication
with the forecastle space. These compartments are tiled. On the port side, forward, is
a bench and abaft this is a drying room, fitted with steam pipes and racks. Adjoining
the drying room and occupying the after end of the port side is the crew’s galley, con-
taining an oil-fuel range and the usual galley fittings. This galley can be entered either
from the forecastle space or from the upper deck.
The forecastle space is enclosed by a steel bulkhead and entered by teak doors, one on
either side. Between these doors, forward of the steel bulkhead, is a companion way
R.R.S. ‘DISCOVERY II’ 83
leading to the crew’s quarters, light being admitted by a small port above the companion.
A small hatchway is provided forward of the windlass for access to the forepeak store
and compartments below.
FOREDECK (Plates IV, V)
The forward part of the upper deck between the break of the forecastle and the bridge
is clear of deckhouses. The foremast is placed 6 ft. abaft the forecastle bulkhead and
carries a large crow’s nest 60 ft. above the water-line, with the searchlight platform just
beneath it. A square sail yard, hoisted on a traveller on the fore side of the mast, is
crossed for the purpose of carrying a large square foresail. The yard is generally carried
in reserve, housed alongside the mast. Abreast of the foremast on the starboard side
is a large reel carrying 600 fathoms of 2?-in. mine-sweeping wire intended for anchoring
in deep water. This reel can be driven by a messenger from the windlass drum-end,
through the starboard forecastle door.
The centre of the foredeck is occupied by the fore hatch, fitted with a portable steel
cover which is bolted down at sea. The cover carries six watertight hinged skylights
which provide the main ventilation and lighting for the officers’ accommodation below.
The hatch gives access to the fore hold where all the food, clothing and canteen stores
are carried. The gaff of the fore trysail is used to work stores through this hatch.
Abaft the hatch, on the port side, wood chocks are provided for carrying a Norwegian
pram; and on the starboard side a potato locker, capable of carrying five tons, was con-
structed during the first commission in the position formerly occupied by a dinghy.
A large watertight wooden locker, used for preserving specimens of Cetacea in salt,
occupies the space close to the bulwark abreast of the potato locker. On the port side,
just forward of the bridge, are two davits and reels and an auxiliary engine for making
scientific observations (Plate X, fig. 1).
LABORATORIES AND DECK HOUSES AMIDSHIPS (Plates IV, V)
The open fore deck leads aft in two alleyways to a position near the middle length of
the vessel, and from this point communication aft is continued by inside alleyways be-
tween the engine- and boiler-room casings and the inboard bulkheads of the deckhouses,
abaft the stokehold fiddley, which here extend right out to the waterways along the
ship’s side. Two hinged steel breakwaters, 3 ft. high, are fitted abreast the forward ends
of the laboratory deckhouses, and can be used as gates to close the forward ends of the
outside alleyways in rough weather.
Between the two outside alleyways, on the upper-deck level, are the main scientific
laboratories, with an entrance lobby, entered from either side of the ship. Of the space
provided, the biological laboratory (Plate VIII) occupies about two-thirds, and is situated
on the starboard side. It is separated from the smaller hydrological laboratory (Plate IX,
fig. 1) by a fore and aft wooden bulkhead.
The laboratories are entered from the lobby by large double doors, and in each of
them there is also a door opening directly on to the deck. These outside doors, like all
84 : DISCOVERY REPORTS
others throughout the ship, are of heavy pattern, strongly made of doubled teak and
insulated. The doors of the laboratories and lobby are exposed in the waist of the ship,
and it was found impossible to keep them watertight in heavy weather. ‘To overcome this
difficulty special portable steel storm doors are provided for clamping over the teak
doors during bad weather.
The lobby, which is panelled in light oak, is provided with small settees in the two
forward corners, while the two after corners are divided off by steel bulkheads. On the
port side aft is a small room with wash basin for officers’ use, entered from the lobby, and
here a door is fitted giving access under cover to the after part of the vessel. This is an
emergency door only required in heavy weather when the watertight doors in the screen
bulkheads are closed. On the starboard side are two officers’ lavatories, which are
entered from the deck. The central part of the lobby is occupied by double staircases,
one leading up to the wardroom and the other down to the officers’ accommodation.
Abaft the lobby and between it and the boiler casing is placed the ship’s galley,
entered from either side by halved steel doors and fitted with an oil-fuel range with two
ovens and the usual galley equipment.
The stokehold doors, also of steel, adjoin the galley, and immediately abaft the stoke-
hold entrance are transverse bulkheads, pierced by doors which give access to the
internal alleyways leading aft.
The two square spaces on each side of the galley and stokehold entrances were found
to be difficult to negotiate in heavy weather, being situated just in the waist where the
ship has least freeboard, and bulkheads have since been built extending diagonally
across from the after corner of the lobby. The bulkheads are fitted with hinged storm
doors and readily throw off any heavy water that may come on board. The enclosed
space abaft the bulkheads has been found very useful for the storage of meat and ready-
use galley stores.
The two blocks of houses abaft the stokehold, outside the covered alleyways, are sub-
divided by steel bulkheads into spaces which are put to a variety of uses. On the star-
board side, commencing forward, is the ship’s office, with the usual fittings and with the
canteen opening from it. Immediately abaft the canteen is the petty officers’ lavatory,
while the after space on this side is fitted as a net store. On the port side, forward, is
a small compartment originally intended for galley stores; but since the construction
of the bulkheads enclosing the galley spaces it has been converted into a carpenter’s
shop, and now contains benches, a vice, and racks for carpenter’s tools. Next to the
carpenter’s shop is the instrument store (p. 97), and abaft of this store is the petty
officers’ bathroom. The after compartment of the port side block is the largest of all,
and is arranged as a laboratory (Plate IX, fig. 2), with one door opening into the alley-
way and another on to the after deck.
In the alleyway on the starboard side is a fire locker built into the engine-room casing
and fitted with a hydrant and storage space for a supply of Foamite. The Foamite is
provided for extinguishing oil fires, but the hydrant can also be used as an ordinary fire
main.
RRS DLSCOVE RY Tl: 85
The engine-room casing is entered by steel doors, one on each side. The after end of
the casing is in the thwartship line of the two blocks of side houses and is partitioned off
to form, on the starboard side, a companion way to the petty officers’ mess, and on the
port side a chamber containing the refrigerating plant.
AFTER DECK (Plates IV, V)
Abaft the engine-room casing, and separated from it by the thwartship alleyway con-
taining the entrance door to the petty officers’ mess, is a large steel house containing the
main trawling winch (Plate XI). This winch, which is provided with two drums carrying
1000 and 5000 fathoms of wire rope, has been transferred from the R.R.S. ‘ Discovery’
and has already been described,' but in the new vessel it was fitted with new ball-
bearing traversing-gear leads and with steam controls on both sides of the house. ‘The
ends of the main shaft project through the house on either side and are provided with
warping drums. The winch house and winch position are specially arranged to ensure
that the operator, facing aft, has a full view of the operations and can give immediate
response to signals. The after end of the house can be closed when required by large
steel folding doors. A small auxiliary drum, with chain drive from the main shaft of the
winch, stands just abaft the winch house on the starboard side.
The boat deck terminates in line with the after end of the winch house, and the rest
of the after deck is open. The centre portion is occupied by the after hatch. This is of
similar construction to the fore hatch; but only the after portion has a movable cover,
and the fore part is fitted with watertight skylights, providing ventilation and lighting
for the petty officers’ mess. The movable after section gives access to the after hold.
Midway between the after hatch and the winch house is the mainmast, carrying a
3-ton derrick on its fore side for hoisting and lowering the motorboat, and a gaff for the
free-footed mainsail on the after side. This gaff is also used to work the after hatch.
A winch and davit, similar to those on the forecastle head, but used for working vertical
plankton nets, are placed abreast the winch house on the port side (Plate XI, fig. 1).
Fairleads for the trawl warps and the usual bollards and mooring pipes are fitted.
The poop (Plate XII, fig. 1) is raised only 3 ft. above the upper deck and is approached
by wide ladders on either side. In the middle line, about 6 ft. abaft the break of the
poop, a powerful samson post is stepped, carrying a derrick capable of lifting 6 tons,
which will plumb 6 ft. beyond the taffrail. This is used for working heavy deep-sea nets
and trawls, and can also be used on the fore side of the post if necessary. ‘Two roller
fairleads are arranged, one on either side, in the bulwarks right aft, and for the rest the
poop is quite clear of obstructions, a great assistance in the rapid handling of trawls and
large tow-nets.
The poop space is entered by a small circular torpedo hatch on the port side, and is
mainly occupied by the rudder-head, quadrant and steering engines, all of which are of
very heavy construction for Antarctic service. The forward port corner of the space is
divided off into a small lamp locker fitted with racks and oil tanks, and an open wooden
1 Kemp, Hardy and Mackintosh, Objects, Methods and Equipment, Discovery Reports, 1, pp- 160, 161.
DXIII a
86 : DISCOVERY REPORTS
locker originally intended for potatoes, but now used for deck stores, is placed just abaft
the lamp locker. Hand steering gear is also provided and a screw quadrant brake; the
space is too confined to permit the successful use of relieving tackles, although they are
provided for use in emergency.
BOAT DECK (Plate IV)
The boat deck, communicating with the fore deck by a steel ladder on either side, and
with the after deck by a teak ladder on the starboard side, carries the wardroom, sick
bay, wireless room and boats. The wardroom house, of steel, extends the width of the
ship, except for an alleyway on either side and across the fore end of the boat deck. It
contains the wardroom and the wardroom pantry, which is a long narrow compartment
set abaft the wardroom and communicating with it by a door. The wardroom (Plate VII,
fig. 1) is entered from the boat deck by an insulated teak door on either side and from
the lobby below by a double staircase. It is panelled in light oak, with furniture of the
same wood, and contains two fore-and-aft tables with seating accommodation for twenty
persons. Plenty of light is admitted by Stone’s square windows placed on three sides,
and there are two large steam heaters. In the after corners of the wardroom are two
small alcoves on either side of the staircase: that on the starboard side is fitted with
a settee and a small table and bookshelves, while on the port side is a wine locker.
A sideboard is placed in the middle line against the fore bulkhead of the wardroom. The
wardroom contains a series of pictures of earlier vessels which have borne the name
‘Discovery’.
The pantry contains a sink, a hot press, a percolator and a milk emulsifying machine,
with a lift communicating with the galley below. Teak outside doors on both sides of
the pantry open on to the boat deck.
Immediately abaft the wardroom house are a galley skylight abutting on we pantry
bulkhead, the funnel casing, two large stokehold ventilators, and a grating admitting
light to the fiddley. The funnel is large and elliptical, and has a rake of 2 in. per foot.
Abreast of the funnel casing two 25-ft. lifeboats built to Board of Trade requirements
are carried in ordinary drop chocks and manipulated by swing davits of standard pattern.
Hinged steel engine-room skylights fitted with glass ports, together with engine-room
ventilators, occupy the centre of the boat deck abaft the funnel casing, and immediately
abaft the skylight casing is a steel deck house containing the sick bay and wireless room.
Two 25-ft. Admiralty pattern whalers, equipped to Board of Trade requirements, and
housed and hoisted in the same manner as the lifeboats, are carried on either side of the
sick bay and wireless room. On top of the sick bay an 18-ft. part-decked motorboat with
a 12 H.P. Parsons engine is carried athwartships in specially strengthened chocks, and
the main derrick is used for hoisting the boat out and in.
The wireless room is entered from the port side by an insulated teak door, the
operator’s table and apparatus being arranged along the starboard side. The installation
consists of a modern r$ kilowatt valve transmitting apparatus with a separate emergency
installation which will give communication on medium wave-lengths. The ship is also
RRS. “DISCOVERY II’ 87
equipped with a short-wave transmitter and a combination receiving set with which
wireless communication with England can generally be maintained: blind areas are
occasionally found in the Southern Ocean in which both the despatch and receipt of
long distance signals prove impracticable. A direction finder is fitted by which the ship
can obtain her own position in relation to land stations and the position of other vessels
in relation to herself.
The sick bay (Plate VII, fig. 3) consists of two compartments, a dressing room and the
sick bay proper; these are separated from the wireless room by a steel bulkhead, and
from each other by a fore and aft wooden bulkhead with a communicating door. The
dressing room on the starboard side is the larger compartment and contains a settee, a
sink, and a large medicine chest, together with a desk and a cupboard for the accommo-
dation of medical stores. A Phillips X-ray outfit and a dental machine are provided.
The sick bay itself contains two swing cots, one above the other, and a wash basin. The
lighting of this house is by square wooden-framed drop windows, and both compart-
ments have doors opening on to the boat deck. A narrow alleyway bounded by an open
rail separates the after end of the sick bay from the break of the boat deck.
NAVIGATING AND FLYING BRIDGES (Plate IV)
The navigating bridge is situated immediately above the wardroom house, the deck
extending to the ship’s side and flush with the break of the boat deck forward. Teak
ladders on either side, placed just abaft the wardroom doors, lead from the boat deck.
The deck house on this bridge is of teak and contains the chart room, an echo-sounding
compartment, the captain’s cabin and a small survey office. Forward of this house and
abutting on it is the wheel house or wheel shelter, eight feet wide and fitted with square
drop windows on each side and in front. The wheel house is entered by sliding doors on
either side and contains the wheel, Telemotor steering gear, steering compass, flag
lockers, speaking tubes and a telephone to the wireless room. ‘Two Kent’s clear-view
screens are fitted in the forward wheel-house windows to enable the officer of the watch
to keep a good look-out in snowstorms and heavy weather, and at the angles of the bridge
two 10-in. Admiralty searchlights are mounted. The bridge, at its fore end and for
10 ft. along each side, is protected by a teak panelled rail and the after end by an open
rail covered with painted canvas. In the forward wings of the bridge are engine-room
telegraphs with extensions to the flying bridge. On the starboard side, just beneath the
ladder leading to the flying bridge, an electrically driven Kelvin sounding machine is
fitted, and an electrically operated revolution indicator is placed on the port side. Flag
lockers and a sanitary tank are placed abaft the house.
The chart room and echo-sounding compartment occupy the whole width of the
forward section of the house. The chart room is 7 ft. wide; it has an insulated teak door
on the starboard side, a door communicating with the echo-sounding compartment on
the port side and two windows opening into the wheel house. It contains a large chart
table with drawers below, a chronometer box, lockers for instruments, the receiving
portion of the direction-finding apparatus and the recording dial of the Chernikeef log.
2-2
88 DISCOVERY REPORTS
The echo-sounding compartment contains three echo-sounding machines and recorders
of the Admiralty pattern, and the recording dial of the Munro anemometer. Further
reference to the sounding machines is made below on p. 102.
On the starboard side, abaft the chart house, and communicating with it by a sliding
door, is the captain’s cabin, which is panelled in light oak, and on the port side is a small
compartment used as a survey office.
The flying bridge extends above the house on the navigating bridge, with wings
running out to the ship’s side at the fore end. It is reached by a teak ladder on either
side. It is protected by a teak-capped open brass rail covered with a painted canvas
weather cloth and is generally used for coastal navigation and surveys, and sometimes
for ice work, as a better view may be had from it over the forecastle head.
In the midship line, near the forward part of the flying bridge, is the standard compass,
with a Kelvin ro-in. dry card. Abaft the compass is the aerial of the direction finder,
the receiver for which is in the chart house below. Next aft is a stand for a metre range
finder, and an ordinary ship’s semaphore surmounted by a Morse flash lamp. On the
starboard side, in the after corner of the bridge, is a g-ft. range finder, which is used in
running surveys. On the port side is the vane of the Munro anemometer, the dial of
which is in the echo-sounding cabinet. A portable chart table is carried close to the
forward rail on the same side.
MAIN DECK (Plate V)
Between the stem and the collision bulkhead, a fore-peak storeroom is provided for-
ward of the chain locker; access to both these compartments is by a hatchway in the
upper deck.
The crew’s quarters, entered by a companion from the forecastle space, occupy the
main deck between the collision bulkhead and the officers’ accommodation. The mess
deck is divided in the middle line and the half length of the flat by wooden partitions,
the stokers occupying the smaller space which comprises the port after portion of the
flat. In the seamen’s mess deck wooden bunk accommodation is provided for sixteen
men, and the usual lockers and tables are fitted. The stokers’ mess has accommodation
for six men.
The officers’ accommodation (Plate VII, fig. 2) connects with the mess deck by means
of a watertight door in the dividing steel bulkhead and contains fourteen cabins for
officers and scientific staff, arranged along each side of the ship. At the forward end are
two bathrooms, one on each side, fitted with calorifiers and wash-basins. Since the main
deck is below load water-line the waste water is run into a sanitary tank and pumped
over the side. The cabins are all of the single berth type and each is provided with a
steam heater and an electric fan. There are no portlights in the main deck, but light is
admitted into each cabin by stout double glass decklights. Ventilation is provided by
brass screw mushroom vents to each cabin, but in heavy weather it was found difficult
to keep these watertight, and in high latitudes they were always unshipped while at sea
and the brass deadlights, provided for the purpose, screwed up in their places.
R.R.S. DISCOVERY II’ 89
The after end of the officers’ accommodation is bounded by the stokehold bulkhead,
through which a steel watertight emergency door gives access to the stokehold on the
starboard side. In the middle line aft is a large linen locker, and the double staircase,
leading up to the laboratory lobby, abuts on the fore side of this linen locker. On the
port side of the staircase is the cabin of the scientific officer in charge (Plate VII, fig. 4),
which is larger than the other cabins and is panelled in oak.
The centre part of the officers’ accommodation is partitioned off by wooden bulk-
heads to form a photographic room, with the door at the after end and a dark room
leading from it.
Forward of the photographic room is the fore hold, which extends from the main oil
tanks just abaft the coaming of the fore hatch to the collision bulkhead and down to the
double-bottom tank tops. The square of the hatch and the wings in the way of it are
clear, and the fore end is divided by wooden battens into tiers of lockers which are set
apart for special stores such as medical, canteen, and clothing, while the main clear
section is used for foodstuffs.
The petty officers’ mess deck extends from the after engine-room bulkhead to the
forward bulkhead of the after hold tween deck and, like the officers’ accommodation,
is divided into cabins along each side. Each of these cabins is arranged to accommodate
two men, and the centre space of the flat is occupied by a long mess table. A pantry,
with hot press and calorifier, occupies the port forward corner of the flat. Inboard of
the pantry is a cold store, consisting of two separate freezing rooms and a small air-lock
or handling chamber, in which boxes for making ice are fitted. Freezing is effected by
an ammonia refrigerator arranged in a compartment built on to the after end of the
upper deck as previously mentioned.
The after hold extends under the petty officers’ mess deck, forward to the engine-
room bulkhead and aft to the line of the poop front bulkhead. This hold is used only for
scientific stores and is fitted with racks and bins for the storage of nets, bottle boxes and
all kinds of scientific gear.
Throughout the ship all living quarters and enclosed spaces in which men may be
required to remain for some considerable time are insulated on all surfaces exposed to
sea or air. Thus in the officers’ and petty officers’ accommodation the outside walls of
the cabins and the deckheads are insulated, and in the case of the deck houses, all out-
side bulkheads as well. This insulation, which has proved very effective, consists of
fireproof cork slabs between the exposed surfaces of the bulkheads or decks and the inside
panelling.
ENGINE ROOM
The machinery installation consists of a set of single-screw triple-expansion surface
condensing machinery specially designed and constructed for service in the Antarctic
and to contend with the low temperatures prevailing in these latitudes.
Particular attention has been paid to bearing surfaces, which are specially large to
ensure the machinery working for long periods without adjustment.
go DISCOVERY REPORTS
The cylinders of the main engines are 18, 285, and 48} 1in. diameter respectively,
having a common stroke of 28 in. The main engines are designed to develop about
1250 H.P. at 128 revolutions per minute. There are no pumps worked off the main
engines, all pumps being independent. The strength of all shafting is well in excess of
Lloyds’ requirements, to ensure, so far as practicable, immunity from damage when
encountering ice; this has already proved advantageous. The reversing gear is of Brown’s
make, direct-acting hand and steam type. An independent surface condenser is fitted
with ample cooling surface to ensure a good vacuum in tropical waters when required.
This condenser is constructed of mild steel and is of Messrs Weir’s regenerative type.
An independent air pump of Messrs Weir’s monotype, and a Weir’s vacuum aug-
mentor are fitted, the latter being intended for use more particularly when the vessel is
passing through tropical waters. An independent auxiliary air pump is also fitted for
harbour service. The circulating pump is of the centrifugal type and two independent
engines are fitted, either of which has ample power for driving the pump.
The propeller shaft is of steel throughout, no liners being fitted, and the stern tube is
provided with the builder’s type of “‘ Newark”? oil-retaining device, enabling the shaft
to be run in oil in white metal bushes. This arrangement has proved satisfactory; no
rebushing has yet been carried out and the wear-down in the bushes has been found to
be negligible. A steam coil is fitted round the stern tube for thawing purposes when low
temperatures are encountered. The thrust block is of the single-collar Michell type
having specially large surface.
The propeller is of the built type. It has a cast steel boss and four portable high-
tensile bronze blades, the blades being of Messrs Stones’ make, machined to pitch and
specially strengthened for contact with ice.
The two feed pumps are of Messrs Weir’s make with float regulators: either is
capable of supplying the boilers at full power. A large general service pump is fitted
for dealing with reserve feed water and other services, and this pump is also avail-
able for circulating the main condenser if required. A small general service pump
is also provided for dealing with the sanitary service, wash deck and similar arrange-
ments. An independent Duplex pump is fitted for dealing with the fresh-water service
only. The evaporator and distiller are of Messrs Kircaldy’s make, the evaporator having
a capacity of 15 tons per 24 hours and the distiller capable of producing ro tons of fresh
water per 24 hours. The feed filter is of the gravity type with float control to Weir’s
pumps. A feed heater is also fitted, using the exhaust from the auxiliary machinery.
Lifting gear is provided in the engine room, together with large tanks for the storage
of lubricating oil.
The boilers are two in number and of the ordinary cylindrical horizontal return-tube
type. They have a working pressure of 200 Ib. to the square inch. The diameter of the
boilers is 13 ft. and their length is 11 ft., the total combined heating surface in both
boilers being 3550 square ft. The furnaces are of Deighton’s corrugated-section with-
drawable type. Boiler mountings throughout are of gun-metal and of Messrs Dew-
rance’s well-known make.
R.R.S. ‘DISCOVERY II’ gl
The oil-fuel installation is of the Wallsend-Howden type working in conjunction with
Howden’s forced-draught system. The oil-fuel pumps are of Messrs Weir’s horizontal
simplex type working in conjunction with Wallsend heaters. The forced-draught fan is
fitted at upper-deck level in the engine room. It discharges to the boilers through a duct
leading between the boilers, giving an equal distribution of air to each boiler. ‘This
arrangement of fan is found beneficial in assisting the ventilation of the engine room,
and does not possess the disadvantage of being open to the stokehold.
A special feature in the machinery installation is the lagging of boilers and pipes. This
is arranged not only to prevent condensation and heat losses, so far as may be possible,
but also as a protection against freezing at the low temperatures in which the vessel is
working. The general thickness of lagging on steam pipes is about 14 in., while on the
boilers it is 3 in. The lagging makes the engine room and stokehold extremely com-
fortable under all conditions of working.
There is a small workshop at the port after end of the engine room. It is par-
titioned off from the engine room by a half-steel bulkhead, with expanded wire netting
in the upper parts, so that the shop can be completely closed. The shop contains a 6-in.
screw-cutting lathe of Messrs Drummond’s make, a small shaping machine and a high-
speed sensitive drill, in addition to a 12-in. diameter emery wheel. The usual equipment
of benches, vices, shelves, lockers, etc., is provided. The whole of the machinery in the
workshop is driven by an electric motor.
The electrical equipment consists of two independent generating sets. The larger set
is capable of supplying power for the whole of the electrical equipment in the ship ; the
smaller set is intended for harbour use and general service, when lighting only and small
calls on power are required. The larger generator has an output of about 28 kw. at 110
volts and is directly coupled to a compound two-crank steam engine of Messrs Sisson’s
make, the cylinder sizes being 6 and g in. with a common stroke of 5 in. This generator
can supply current simultaneously for the whole of the lighting, fans, searchlight, wire-
less, refrigerator, workshop motor, floodlights on derricks and other electrical require-
ments. The smaller generator has an output of about 10 kw. at 110 volts, and is also
directly coupled to a compound single-crank steam engine of Messrs Sisson’s tandem
type.
A large switchboard, of the enclosed type, is fitted at the level of the main-deck
stringer, where it is well sheltered and all parts both back and front are readily acces-
sible. The connections at the back of the board are all open and capable of being readily
examined when required. The whole installation was carried out by Messrs J. Charters
of Glasgow, and it has given very satisfactory service.
A full equipment of spare gear is provided for the main and auxiliary machinery, in-
cluding spare propeller shaft and spare propeller blades.
The ship has a large bunker capacity ; 316 tons of fuel oil are carried in bunkers which
are divided by three fore and aft oiltight divisions into two main and two wing com-
partments. The usual subdivision of oiltight transverse bulkheads and fore and aft wash
plates was not adopted for this ship, the arrangement fitted being considered safe in the
92 DISCOVERY REPORTS
event of ice damage to the sides of the ship. This arrangement of oiltight bulkheads
proved most satisfactory when on one occasion the side plating in way of the bunkers
was badly damaged in the pack-ice, causing leakage in the wing bunkers. The centre
compartment remained intact, leaving the ship with sufficient reserve of oil fuel to en-
able her to reach her destination. The bunkers extend from the after end of the fore hold
to the stokehold bulkhead and are separated from the double-bottom fresh-water tanks
by oiltight wells at either end. The starboard side of the forward well houses the sluice
valve and hydrophone for the deep-water echo-sounding machine. The bunkers are
fitted with steam coils for preheating the oil in cold weather, and permanent steaming-
out pipes are fixed in each compartment.
On account of the long periods likely to be spent at sea, the ship is designed to carry
approximately 140 tons of fresh water. Of this quantity about ro tons is for drinking
purposes and is carried in four rectangular galvanized steel tanks at the after end of the
fore hold. The remainder is carried in the after peak ballast tank and in the fore hold,
stokehold and engine-room double-bottom tanks.
At her trials on November 11, 1929, the vessel was tested over the measured mile in
the Gareloch on the Clyde. She exceeded her contract speed of 13 knots and easily de-
veloped and maintained her designed horse-power of 1250. Her consumption at full
speed is 124 tons per day; with full bunkers this speed can be maintained for 25 days,
giving a cruising radius of nearly 8000 miles. At an economic speed of 10} knots her
consumption is about 7} tons per day. At this speed she can steam for 42 days and has
a cruising radius of about 10,500 miles. In practice, however, her cruising range is
considerably less than this, since, for the scientific work, the ship is normally hove to
for several hours every day. During these hours the consumption of fuel is not much
reduced although no distance is made.
SPECIAL ACCOMMODATION FOR RESEARCH
BIOLOGICAL AND HYDROLOGICAL LABORATORIES
The positions of the biological and hydrological laboratories, amidships on the upper-
deck level, are shown in Plate V and they are illustrated in Figs. 1, 2 and Plates VIII, IX.
The fore-and-aft bulkhead which separates them stops short of the common double-
door entry in the after bulkhead, which thus allows open communication between the
two. They receive natural light and ventilation by means of Stone’s square pattern
watertight windows of which there are seven in the biological and five in the smaller
hydrological laboratory; they can be protected by mild steel storm shields in heavy
weather. The laboratories are electrically lighted by ceiling lights, an adjustable bracket
lamp over each of the working spaces on the benches and a large low hanging lamp over
the swinging table in the centre of the biological laboratory. In both laboratories the
walls are of white enamelled pitch pine, the bench tops of teak, and the chairs, cup-
boards and drawers of light oak.
RRS. DISCOVERY Il* 93
Around the starboard and forward sides of the biological laboratory there runs a
working bench at which there are four working places, three on the forward and one on
the starboard side. Each is opposite a window and each has a chair with a swivel top
which can be clamped in any position (Figs. 1, 2). Underneath the bench and between
the chairs are tiers of small drawers. At the middle of the port side is a sink with taps
supplying salt water, hot and cold fresh water, spirit and strong and weak formalin, and
beside the sink is a vacuum connection from the main engine condenser which will give
a vacuum equivalent to about 25 in. of mercury. Forward of the sink is a bench con-
tinuous with that of the forward side, with drawers and a card index to the library
beneath a portion of it. On a shelf above the sink is a row of 5-litre aspirator bottles
containing graded alcohols and preserving fluids, their taps protected by a brass guard
rail. Above the bench forward of the sink are two 1o-gallon cylindrical earthenware
containers, one for strong and the other for diluted formalin. Each has an ebonite stop-
cock from which a rubber tube leads to an ebonite tap over the sink. A supply of 75 per
cent spirit is kept in a 40-gallon tank abaft the flying bridge, and is piped down to another
tap over the sink. On the after bulkhead is a large bottle rack for the storage of con-
venient numbers of all sizes of specimen jars, and below it are tiers of baize-lined drawers
for small glass specimen tubes and miscellaneous apparatus. The bottle rack is similar
to that described in Discovery Reports, 1, p. 170.
A large gimbal table occupies the centre of the laboratory and is continuous at its
after end with a bench which reaches a higher level and is fitted with drawer and cup-
board space beneath. The swinging table is similar to that previously described (vol. 1,
p. 169), but is larger and has an enamelled iron guard-rail level with the table top, and a
75-lb. weight slung close to the deck. The bench on the after side of it has a detachable
fiddle divided into compartments which fit specimen jars of all the sizes kept in stock.
Part of the cupboard space beneath the bench is so designed that ten trays of $-lb.
specimen jars can be taken out of their storage cases and used in it as drawers until the
jars are filled and the trays replaced by others containing empty jars. A book-shelf of
two tiers runs around the forward and the starboard sides of the laboratory above the
windows.
A bench fitted to carry the burettes necessary for the analyses of sea water runs across
the forward end of the hydrological laboratory (Plate IX, fig. 1). It has two working
places, each opposite a window and each with a swivel-topped chair. Ona high shelf on
the inboard bulkhead above this bench are two 20-litre reservoirs of silver nitrate
solution and one of sodium thiosulphate solution, the former for the determination of
the salinity, the latter for that of the oxygen content of sea water. The titration of sea-
water samples with silver nitrate solution is always done at the inboard working place,
which is, for that reason, shut off from strong natural light by a blind over the window
and a heavy curtain between it and the outboard working place and the other windows.
Above the bench is the recording mechanism of a Negretti and Zambra distance thermo-
graph, the thermometer bulb of which is in a pocket in the ship’s hull at a point about
14 ft. below the surface. It gives a constant record of the temperature at that depth.
DXIII
RSS
SSAS SSS
wen
an
-€3
Fig. 1. The biological laboratory
R.R.S. ‘DISCOVERY II’ 95
On the starboard side of the laboratory is a bench and a sink, and drawers are fitted
beneath the bench. The sink is supplied with hot and cold fresh water and cold salt
water, and near the taps there is a vacuum connection from the engine room. The short
section of bench forward of the sink is lead covered and has a drying rack above; aft of
the sink it is of teak and is continued to the entrance from the biological laboratory. On
it, near the sink, is stowed a 5-gallon copper container for distilled water, and a second
similar container is stowed on a bracket on the outboard bulkhead abaft the bench.
On the port side of the hydrological laboratory there is another bench with a tier of
drawers below it and some space for stowing boxes of water sample bottles. The bench
CHEMICAL
LABORATORY
CHEMICAL CUPBOARD Z
BOTTLE RACK
Fig. 2. Plan of biological and hydrological laboratories. c, cupboard under bench. d, drawers under bench.
f, hinged flap of bench. /, bracket lamp. 7, radiators. s, sinks. ¢, formalin tanks over bench. w, receiver for
waste spirit under bench.
top is fitted with racks for the comparator tubes used in estimations of the phosphate,
silicate and nitrate content of sea water. Along the after end of the laboratory is a large
cupboard for the storage of chemicals with a fiddle on top for small Winchester bottles
and other stores. Book shelves run along the port side above the windows.
In both laboratories there are numerous minor fittings which occupy most of the wall
space. They include racks for burettes, pipettes, measuring cylinders, Petri dishes, glass
bowls, labels, tubes and reagents. Three small gimbal tables suitable for holding open
Petri dishes are swung on brackets from the bulkheads over the benches, and each
working place has before it a rack for receiving large numbers of specimen tubes. In the
3-2
96 DISCOVERY REPORTS
biological laboratory the microscope cases are screwed to the benches, and the micro-
scopes themselves can be similarly secured.
Some further details of laboratory equipment are given later under “‘ Laboratory
Methods”.
ROUGH LABORATORY
The rough laboratory is situated at the after end of the deck housing on the port side,
conveniently near to the after vertical reel and the poop, from which nets are worked.
It is a long narrow room, with one door opening to the after deck and another near its
forward end to the port alleyway (Plate IX, fig. 2). A high bench for the keeping of
deck log books, for the reduction, bottling and labelling of plankton samples and for the
sorting of the catches of dredges and trawls, runs along the outboard side. Underneath
it are drawers and open stowage space for the large trays and bowls used for sorting the
hauls of dredges and trawls. At its forward end is a sink with salt water and hot and
cold fresh-water taps. Above the sink is a 20-litre aspirator bottle containing weak
formalin. Against the forward bulkhead on the inboard side is a gimbal table smaller
than that in the biological laboratory and above it is a rack for 1 and 3 lb. jars—those
most frequently used for the larger plankton samples.
On the inboard side there is a low cupboard in the after corner and running forward
from it two long racks, the lower with circular holes for the stowage of the larger plank-
ton net buckets, the higher for open glass jars used in plankton work. Forward of the
lower rack and between it and the forward door is an electrical centrifuge.
On the bench there are racks for specimen tubes and for the three sizes of settling
tubes which are sometimes used for concentrating plankton hauls; on the after cupboard
there is a fiddle for the }-lb. jars which are always used for small vertical plankton hauls.
The laboratory is naturally lighted by three ports in the ship’s side above the bench and
electrically by two ceiling lights and a bracket lamp over the bench.
A speaking tube from the rough laboratory to the bridge has recently been fitted so
that easy communication can be maintained between the scientific officer supervising the
fishing of the nets and the officer of the watch handling the ship.
PHOTOGRAPHIC ROOMS
The enclosed space in the centre of the officers’ accommodation on the main deck is
divided into two unequal parts. The smaller forward part, entered by a door from the
larger room aft, is the dark room. It contains a sink with cold fresh- and salt-water taps,
a lead-covered bench, racks for developing dishes, shelves and cupboards for the storage
of chemicals and photographic plates, and other usual dark-room equipment. The dark-
room lamp above the bench can be controlled either by a switch at its base or by another
just inside the door. A Phillips X-ray viewing lantern is fixed to the bulkhead above
the sink.
The larger room is used occasionally for photographic purposes and partly as a store-
room. On the after port side is a bench carrying a sliding horizontal whole-plate camera
R.R.S. ‘DISCOVERY II’ 97
for photographing charts and illustrations. On the port side of the forward bulkhead is
a sink with taps for hot and cold fresh water and salt water, and above it a large washing
tank for X-ray negatives and large plates. In the starboard side of the forward bulkhead
is the door to the dark room. Immediately abaft the dark-room door on the starboard
side stands a tier of large chart drawers with a flush top, part of which is constructed to
form a chart tracing table consisting of a heavy plate of glass which can be illuminated
by a movable lamp from below. This space was formerly occupied by a half-plate
camera, fixed vertically over a platform on which small organisms could be photo-
graphed with the aid of powerful spotlights.
Farther aft on the starboard side there are two high tiers of drawers used for storing
spare stationery and apparatus. In the after port corner is a lift for passing stores to the
biological laboratory above. It opens at the after end of the dividing bulkhead between
the biological and hydrological laboratories.
Two book-shelves along the port side and one along part of the starboard side of the
room are used for carrying a part of the scientific library.
The photographic equipment of the ship includes a Sanderson half-plate camera with
which records of the work on board, of whaling activities, of natural life and of the
places visited are made.
SCIENTIFIC INSTRUMENT STORE AND WORKSHOP
The small room between the carpenter’s shop and the petty officers’ bathroom, in the
block of houses outside the port alleyway, is used as a scientific instrument store and as
a workshop for the repair and overhaul of scientific gear. A bench runs along its out-
board side with a port and a bracket light above. A small vice is attached to the bench
and there are two tiers of drawers and open stowage space below the bench. All the
available wall space is occupied with racks holding Nansen-Pettersen and Ekman
water bottles, metre recording blocks, echo-sounding machine spares, current meters,
release gears, Baillie sounding rods, harpoons and harpoon guns, sporting rifles and
ammunition. On the deck against the bulkheads are racks for depth gauges and stream-
lined leads.
Of the two or three scientific assistants, each of whom ranks as a petty officer in the
ship’s complement, one is a man having electrical and general technical knowledge. His
first duty is the care and operation of the echo-sounding machines (p. 102), but he has
in addition the general care of scientific gear used on deck, with the exception of nets.
The scientific storeroom is at the same time his workshop.
NET STORE
The long narrow room, which is the after compartment in the starboard block of
deck houses, is used as a net store and workroom. Its position on the starboard side
corresponds with that of the rough laboratory on the port side, and it is in a similar way
near to the points from which nets are worked. ‘The single door opens to the after deck.
There are deep racks against the forward bulkhead for the accommodation of spare
98 : DISCOVERY REPORTS
I m., 70 and 50 cm. nets bent on frames ready for use, and above these racks are bins
for the storage of new nets. On the starboard side forward is a small bench with a port
above, and aft of it are tiers of large bins for line, trawl twine, and general plankton net
and trawling gear. On the port bulkheads are racks holding spares of small plankton
buckets and strong fittings for the stowage of the heaviest release gears.
One member of the ship’s company is rated as net man with the rank of a petty officer.
The nets and the heavier scientific gear stored in the after hold, which is used entirely
for scientific stores, are under his charge. He uses the net room both as a store and as
a workroom for the assembling and repairing of nets.
SCIENTIFIC EQUIPMENT
The scientific equipment and methods used in the ‘Discovery II’ are in general
similar to those described in vol. 1 of the Discovery Reports, but certain new departures
have been made which should be described here.
DECK GEAR
The main winch, light deck machines and wire sounding gear are similar to those
used in the ‘Discovery’ but with many detailed improvements resulting from ex-
perience. The positions of the machines, however, have in most cases been altered. The
present arrangements are shown in Plate IV. It will be noted that the main winch (Plate
XI, fig. 2) is now placed aft, a position which gives the best possible leads for the wire
ropes and allows the winch man a clear view of the operations on the poop deck.
Two pedestal fairleads are installed abaft the main winch, one opposite the main and
one opposite the auxiliary drum. Each has two Tyne metal sheaves running in roller
bearings. Farther aft, on each side of the forward corners of the skylight to the petty
officers’ quarters, are two recording sheaves, 1} m. in circumference, mounted on steel
pedestals (Plate XII, fig. 2). These sheaves are also of Tyne metal, running in special roller
bearings, and operate dials recording in metres the length of warp paid out. There are
two stern fairleads, one on each side of the poop (Plate XII, fig. 1), fitted with one large
horizontal and two smaller vertical rollers. The warp from either drum of the main
winch can be led to either fairlead, but in practice it has been found more convenient
to use that on the port side.
A large floodlight is fitted to the top of the samson post to facilitate the working of nets
from the poop at night, and the surface of the water aft is illuminated by a small light in
the stern rail which is carefully recessed to prevent its being fouled by nets or trawls.
Davits, accumulators and recording dials of an entirely new type designed by Dr
Kemp are used in conjunction with the deck machines (Figs. 3, 4; Plates X, XI). The
davits for vertical plankton nets and water bottles consist each of a tubular steel post
(15 ft. 6 in. high for the nets and Ekman type water bottles and 12 ft. for the Nansen-
Pettersen water bottle) placed opposite the reel of wire. A horizontal derrick arm, 5 ft.
TEACCUMULATOR -
\
Fig. 3. Elevation of forecastle head davit.
ZY
LZ)
METRE
7 SHE AVE
TH WARTSHIP_LIN E
Fig. 4. Plan of forecastle head davit.
100 : DISCOVERY REPORTS
in length, with a metre sheave suspended at the end of it, projects from the top of the
post, and when swung outboard is fixed securely at an angle of 45° from the rail by
means of a light tubular steel stay which extends from a position on the deck or the rail
to the outboard end of the derrick. An alternative deck position for this stay is provided,
so that the davit can be turned inboard and secured in that position. The wire passes
first to a sheave at the top of the post, thence down to another sheave attached to the
head of an enclosed spring accumulator mounted alongside the post, up again over a
third sheave also at the top of the post, thence to the metre sheave at the end of the arm
and so down to the water. The metre sheave is connected by a flexible drive to a large dial
counter, reading to 10,000 metres and fixed to the rail in a position facing the operator
working the machine. The advantages of the new davits lie in the height of the horizontal
arm above the water, which allows water bottles and nets to be hauled up to, or above,
the level of the rail, in the ease with which the dial can be read and in the very efficient
accumulator mechanism. The latter consists of a tubular casing to the top of which the
sheave is attached. Inside it are compression springs and a rod. The rod is attached at
its upper end to the top of the springs and at its lower end to the deck, so that tension on
the wire causes the sheave and casing to move upwards against the springs. Slight
tension, such as occurs when a net is being lowered, engages a light spring, but heavy
tension, as when the net or instrument is being hauled up, brings a second and stronger
spring into operation. The casing in which the springs work is watertight and is kept
filled with oil.
In cold weather in the Antarctic the sheaves on the davits sometimes freeze in
their bearings. To thaw them paraffin flares were formerly used (Plate X, fig. 1), but
steam jets on flexible connexions have now been installed for this purpose.
APPARATUS
The water bottles, plankton nets, release gears, dredges and trawls are mostly
similar to those described in vol. 1, pp. 181 et seg.; but both in apparatus and methods
some innovations have been made.
The working of large closing nets has been notably improved by the use of a closing
band operating on the inside instead of on the outside of the net. When a large net is
closed in the ordinary way with an outside closing band and hauled towards the surface
the resistance to the water is distributed asymmetrically, and the resulting surging of
the net has been found to cause serious damage to the enclosed organisms. With 2-m.
stramin nets the difficulty has been overcome in the following way (see Fig. 5). A
closing band of 6-mm. wire is passed through rings on the inside of the net and fixed to
the release gear. A stray line of similar wire doubled is attached at one end to the re-
lease gear and at the other end to the shackle at which the bridles meet. This stray line
is of such a length that when the bridles are released the ring of the net falls back until
the closing band has completely throttled the net. The stray line and bridles then,
however, take up the weight of the ring and upper part of the net which maintain their
R.R.S. “DISCOVERY II’ IOI
ordinary position square to the towing warp. There is then a symmetrical resistance to
the water, and surging is avoided.
An appliance first used in the ‘ Discovery II’ in 1933 is a phytoplankton net designed
by Mr F. W. Harvey of Plymouth, who has already published a detailed account of it.!
The net is quantitative, the volume of water which passes through it being measured
by a vane and revolution indicator fixed near the mouth. Samples of phytoplankton
are treated with acetone, and the amount of pigment extracted is measured by com-
a b ¢ b de
Fig. 5. Internal closing mechanism for large nets. A, open; B, closed. a, “ fishing”’ part of net. 4, throttling
band. c, bridles. d, release gear. e, towing warp. f, stray line.
parison with a series of colour standards. The net provides a swift and convenient
method of comparing the relative abundance of phytoplankton in different localities,
and is in daily use while the ship is at sea.
In the ‘ Discovery II’ it has been found possible to take vertical hauls with the Young
Fish Trawl (TYF), a stramin net with the fore part of large meshed netting to facilitate
sinking. The net, mounted on a stream-lined frame 2 m. in diameter, was closed
by an inside throttling line (as described above), and was used over the stern of
the vessel, suspended from the long derrick boom attached to the samson post. A
weight of 180 lb. was employed with this net. The release gear is of a special type with
1 Harvey, F. W., Journ. Mar. Biol. Ass., n.s., xIx, p. 761 (1934); Journ. de Conseil, x, p. 179 (1935).
D XIII +
102 : DISCOVERY REPORTS
a striker of sufficient length to pass beyond the splice and swivel at the end of the warp.
By means of snatchblocks the strain on the warp was partly taken up by a large accu-
mulator spring which gave a very clear indication of the moment when closure was
effected. With this apparatus vertical hauls have been taken successfully to a depth of
3000 m.; but the release gear often proved unreliable, especially in a sea-way. In the
richly populated waters of the Antarctic this method is likely to prove of value, but in
the warmer parts of the Atlantic the plankton is so scanty that adequate quantities cannot
be taken in vertical hauls. The operation 1s in any case laborious and protracted.
A continuous plankton recorder is sometimes in use in the ‘ Discovery II’. It was de-
signed by Professor A. C. Hardy and is an improved form of the model referred to in
vol. 1, p. 189. A description of it will appear in Discovery Reports, vol. x1 (in press).
A new type of depth gauge (Plate XIII) is now used with deep horizontal or oblique
townets. ‘The mechanism is similar in principle to that of the Budenberg gauge, with a
Bourdon tube working through a link motion which magnifies the movement and actu-
ates a pen which traces the changes in depth on a circular card rotated by clockwork.
This mechanism is mounted on a heavy steel base and is enclosed in a cylindrical steel
cover which fits into a circular groove in the base. The groove is lined with a hard
rubber washer. Experience with the Budenberg gauge showed that the leakage of water
into the mechanism, which occurred at all depths over 400 m., was due to the method of
securing the cover on the base. It was found impossible to get an equal strain on the
twelve screw studs which hold the two halves together, and experiments showed that
when the gauge was closed down omitting every other stud, there was, if anything, less
leakage. In the new gauge the base and cover are mounted in a frame consisting of two
vertical steel bolts joined by square steel bars. Through the upper bar is a large screw of
fine thread which bears on the centre of the cover. Thus in place of the twelve studs used
in the Budenberg gauge only a single screw is employed, and when this is tightened the
cover descends evenly on the rubber washer and forms a watertight joint which in
frequent tests has shown no sign of leakage even at a depth of 5000 m.
The apparatus and methods used in hydrological work are similar to those employed
in the ‘Discovery’, though it may be mentioned that reversing and Nansen-Pettersen
thermometers made by Messrs Negretti and Zambra, reversing water bottles by Messrs
R. and W. Munro, Ltd., and Nansen-Pettersen water bottles by Messrs Elliot and
Garrood of Beccles, have given entirely satisfactory results.
SOUNDING MACHINES!
Although the Lucas and Kelvin machines are retained in the ‘ Discovery II’, sounding
is now carried out almost exclusively with the echo-sounding machines. These are of
the British Admiralty pattern and are supplied by Messrs Henry Hughes and Son, Ltd.
They include firstly the oceanic pattern of Deep-Water Sounder with improved hammer
of the balanced head type, an ‘Acadia’ Pattern Recorder, which can be used with the
' We are indebted to Mr H. F. P. Herdman for the information given in this section.
R.R.S. ‘DISCOVERY II’ 103
above hammer, a change-over switch from the oceanic machine being provided, and
a Mark XII magneto-striction shallow-water sounder with curved scale recorder. The
latter has been fitted recently in place of the old Pattern 751 British Admiralty shallow-
water machine.
Soundings of great precision can be taken with the magneto-striction machine. It has
a normal range of 0-230 fathoms, but by alteration of the motor speed it can be made
to record from o to 230 feet over the same depth of scale. The oceanic machine and
the ‘Acadia’ recorder also are more accurate at great depths than the Lucas machine.
The oceanic machine is in continual use, and soundings can be obtained from the
greatest depths at all times when the weather permits. In rough weather the surge of
water on the hull of the ship produces “‘ water noises” which swamp the echo, but
except in severe gales, when it is possible that the aeration of the surface water impedes
the sound waves, a sounding can always be obtained if the ship is hove-to for a few
minutes. The greatest depth so far measured with this machine in the ‘ Discovery II’ is
7882 m.' As long as the ship is at sea routine soundings are taken at hourly or half-
hourly intervals, and if rapid changes in depth are observed the intervals are reduced
accordingly. ‘The recorders are used mainly in coastal survey work, in shallow water or
in any region where a clear delineation of the bottom contour is desired, as when
the ship is passing over shoals, deep troughs or continental slopes; the demarcation of
the Scotia Arc would have been quite impossible by ordinary sounding methods in the
time at the disposal of the ‘Discovery Il’. The value of the recorder in uncharted
coastal regions need hardly be emphasized.
Certain practical difficulties in the running of the machines have been encountered
from time to time, but in the end all have been successfully overcome. The first and
most serious difficulty met with was caused by the ship being mainly in water of which
the temperature rarely exceeded 3° C. and was more usually at o° C. or below. This
caused the hot moist air from the compressor to condense on its sudden expansion in
the deep-sea hammer, thus forming a sticky emulsion with the oil used to lubricate
the piston. After quite short periods of running the piston used to jam and this necessi-
tated the removal of the head from the hammer and the cleaning of both piston and
cylinder, which at times was most inconvenient and caused serious delay. On the
return of the ship to England in 1931 a steam coil was fitted round the hammer and this
minimized the trouble considerably. In 1934, however, it was found necessary to fit a
specially designed trap containing calcium chloride to dry the compressed air before it
entered the transmitter. ‘This made a considerable improvement, as it was then possible
to get twelve to fourteen hours’ continuous running in conjunction with the recorder.
The shallow-water hydrophone, which was enclosed in a small tank of water, was
also seriously affected by the cold water, as the formation of ice in this tank forced the
stalloy base of the microphone completely out of alignment. This difficulty was over-
come by mixing glycerine with the water. ‘he deep-water hydrophone, which is
exposed to the sea, is not affected by the cold water.
1 Herdman, H. F. P., Report on soundings taken during the Discovery Investigations, etc.
104 DISCOVERY REPORTS
The old pattern of deep sea hammer with the unbalanced head was in use with the
oceanic machine until 1935, and although requiring constant attention and adjustment,
gave good results; but during the running survey of the South Shetland Group in
1934-5 it gave trouble continuously and was practically rebuilt on board. These repairs,
however, were only of a temporary character and it was replaced by a new hammer of
the balanced type during the refit in London in August 1935.
The ‘ Acadia’ pattern recorder fitted in 1933 gives excellent results, the proved range
during the third commission being from 20 to 2800 fathoms. ‘Trouble, however, was
experienced with the high tension batteries and the special paper. This paper is wetted
by an endless wick dipped in a tank of water, and complete saturation is necessary as
electrical contact must be made from the travelling pen through the paper to the tank
face before the sounding can be recorded. The ‘starving’ of the paper may result
from its uneven texture, or it may be caused by the wick becoming choked with fluff
and chemicals which rub off the paper as it ‘feeds’ over the wick. To correct the latter
fault the wick can be removed and boiled, but in the former case nothing can
be done except to try a new roll of paper. This difficulty has been overcome in the
Mark XII machine by using pre-saturated paper supplied in sealed containers and fed
directly over a roller to the tank face instead of over a wick.
The battery trouble was more serious but was easily remedied. It was found almost
impossible to maintain the H.T. batteries at a working voltage as they were seriously
affected by the cold and damp. This was due to the door of the echo-cabinet, which
is also an entrance to the chart house, being left open for long periods. As a correct
H.T. voltage is absolutely necessary to produce a good record, and as it was impossible
to have sufficient spare batteries, it was decided to replace them by accumulators.
These were already in existence on board for the direction finding apparatus, and as
the lead to the latter runs through the echo-cabinet, it was a simple matter to fit an
extra switch and lead to the recorder. The charging board for these batteries is in the
chart house, so there is no difficulty in keeping the battery charged to full capacity.
When the Mark XII recorder was fitted in 1935, Messrs Hughes approved this machine
being run from the same battery and a special switch has been fitted which allows either
recorder or the direction finder to be used separately.
LABORATORY METHODS
Methods of sorting, preserving and storing specimens are similar to those described
in vol. 1, pp. 216-20, except that all the jars used are now of the Kilner pattern—with
glass lid, rubber washer and copper ferrule. Two new sizes have been added: one is the
wide-necked 7-lb. jar which is useful for large specimens and heavy catches of plankton,
and the other is the }-lb. size used almost exclusively for plankton samples from the
vertical 70 and 50 cm. nets. Formerly these samples were preserved in tubes, and there
was some inconvenience in reducing the samples sufficiently to get them into the tubes.
The catch can be poured straight into a }-lb. jar from the plankton bucket or settling
R.R.S. “DISCOVERY II’ 105
tube, and the standardization of the storage of vertical plankton samples is a further
advantage. These jars are kept in wooden boxes containing two trays, each of sixty
bottles, and as explained on p. 93, a cupboard in which the trays can be stored is
provided in the biological laboratory.
Neutralized formalin and 75 per cent. alcohol are the preservatives most generally
used.
In an earlier volume (vol. 1, p. 219) we noted that paraformaldehyde was liable to form
in the strong formalin used in the research ships, and that considerable quantities had
thus been rendered useless. This difficulty, possibly though not certainly due to the low
temperatures to which the formalin is exposed, has now been overcome with the as-
sistance of Mr Arthur Ashworth, the manufacturer. He has supplied formalin with an
increased alcohol content, and consequently with a reduced specific gravity, which has
shown no tendency to polymerization when stored on board.
Distilled water for use in both laboratories and for photographic purposes is provided
by a small steam-heated still of Brown’s make which is fitted at the top of the engine
room just inside the port door. The cooling of this still is by salt water, but the water
distilled is from the ordinary fresh water supply.
Sund’s slide rule is used for the direct determination of o, (density at the temperature
of observation). This is an essential operation and the method is quicker and more
accurate than the use of tables.
2}
PLATES II—xIll
SOVERY It’
at
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HIP “Dl
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PLATE III
The Royal Research Ship ‘Discovery II’ at anchor
off Simon’s Town, South Africa
PLATE III
XII
DISCOVERY” REPORTS, VOlE
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PLATE IV
Profile and plan of forecastle and bridge deck
. Searchlight
. Alternative position of searchlight
. Capstan
Crow’s nest
. Wireless aerial
Standard compass
. Direction finder
. Semaphore
. Lifeboat
. Whaler
Il.
TZ:
Motorboat
Samson post and derrick
nee
14.
ie
16.
L7.
18.
19.
. Captain’s cabin
. Wardroom
. Pantry
. Wireless office
. Sick bay
Echo sounding apparatus
Lucas machine
Deep hydrographic machine and davit
Breakwater
Steering house shelter
Chart room
Survey office
PAVE avi
DISCOVERY REPORTS, VOL. XIII
II] AUAAOOSIC, SWa
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PLATE V
Plans of upper and main decks
. Windlass
. Carpenter’s bench
. Boatswain’s store
Drying room
. Crew’s washhouse
. Crew’s galley
Crew’s lavatories
. Skylight to officers’ accommodation
. Shallow hydrological machines and
davits
. Pram
. Dinghy
. Hydrological laboratory
. Biological laboratory
. Lobby
. Lavatory
. Galley
. Officers’ lavatories
. Workshop
. Instrument room
. Petty officers’ bathroom
. Rough laboratory
. Fire-extinguishing apparatus
. Office
. Canteen store
. Petty officers’ lavatories
. Net store
. Refrigerating engine
. Winch house and winch
29.
30.
31.
. Recording fairleads
. Skylight to petty officers’ accommoda-
Plankton machine and davit
Auxiliary winch drum
Pedestal fairleads
tion
. Torpedo hatch to steering engine
. Stern fairleads
. Chain locker
. Seamens’ mess
. Stokers’ mess
. Officers’ bathrooms
. Hatch to forehold
. Officer’s cabin
. Linen locker
. Dark room
. Photographic room and library
. Cabin of scientific officer in charge
. Steward’s store
. Communicating alleyway
. Boiler
. Engine room
. Refrigerating chamber
. Petty officers’ accommodation
. Hatch to after hold
. Hand steering wheel
. Lamp room
. Vegetable locker
. Telemotor steering engine
PALE Vi
DISCOVERY REPORTS, VOL. XIII
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Fig. 3.
Fig. 4.
PLATE VI
R.R.S. ‘Discovery IT’ in pack-ice, 69° 40’ S, 97° 04’ W.
Frozen spray on fore deck and bridge.
Well-deck davits encrusted with ice.
R.R.S. ‘Discovery II’ in light pack-ice, south-west of the South Orkney Islands.
DISCOVERY REPORTS, VOL. XII PISASS vil
RRS. “DISCOVERY II’ IN THE ANTARCTIC
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PLATE VII
Fig. 1. Wardroom.
Fig. 2. Officers’ accommodation.
Fig. 3. Sick bay.
Fig. 4. Cabin of scientific officer in charge.
DISCOVERY REPORTS, VOL. XIII
PLATE VII
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Issued by the Discovery Committee, Colonial Office, London
Vol. XIII, pp. 107-276, plates XIV-XVI
on behalf of the Government of the Dependencies of the Falkland Islands
A REPORT ON OCEANOGRAPHICAL
INVESTIGATIONS IN THE PERU
COASTAL CURRENT
by
E. R. Gunther, M.A.
CAMBRIDGE
AT THE UNIVERSITY PRESS
1936
Price twenty-six shillings net
[Discovery Reports. Vol. XIII, pp. 107-276, Plates XIV—XVI, October, 1936.)
Mae PORT ON OCEANOGRAPHICAL
Ewes Tr LGATLONS IN“THE BERU
COASTAL CURRENT
By
E. R. GUNTHER, M.A.
CONTENTS
INTRODUCTION. . .
EQUIPMENT AND METHODS .
WIND
CURRENT AND DRIFT OF THE SHIP .
‘TEMPERATURE
SALINITY
SEASONAL CHANGES.
COLOUR OF THE CURRENT .
LIFE IN THE CURRENT .
PHOSPHATE CONTENT
CONCLUSIONS ON THE RESULTS OBTAINED.
Currents e.g ee
Origin of the cool water
Coastal upwelling
Hstimationlofipwellingi yale nee
Depth affected by upwelling and water layers involved
Effect of direction of coast-line .
Effect of the sea-bottom contour
Effect of wind
Effect of latitude .
Effect of seiche
Speed of upwelling
The evidence for the theory of subsidence
Sinking of newly mixed water
Centres of upwelling and other irregularities of the current
Phosphate and organic production
Colour of the current
Boundaries of the Peru Coastal Current .
Comparison of normal and abnormal conditions on the west coast
Comparison of conditions on the east and west coasts
SUMMARY
List OF REFERENCES
INDONONs G 6 6 6 o © 6
INDEX 05, “... S75 Rely SRM? Peta RO, i ee
page 109
120
121
125
275
Braves XEV=XVDE Vee ee ee ee) ee i a eyallommesiacess 76
MREPORT ON OCEANOCRAPHICAL
[NWESTICATIONS IN THE PERU
COASTAL CURRENT
By E. R. Gunther, M.a.
(Plates XIV-XVI; Text-figs. 1-71)
INTRODUCTION
HE name Peru Coastal Current has been used to denote that part of the South
Pacific anticyclonic circulation in which northerly current is most conspicuous ; and
whose physical, chemical and biological characteristics are most affected by admixture
with water upwelled from the lower layers.
This report is the outcome of a survey carried out in 1931 by the R.R.S. ‘William
Scoresby’; it endeavours to bring together in a general description the salient features
of the region as a whole, as they appear from a preliminary examination of the data, and
to summarize the literature likely to be useful to those later engaged upon the prepara-
tion of more detailed reports.
The first two sections are introductory; the body of the report is mainly occupied
with an analysis of facts; while hypotheses by which they may be explained are con-
sidered among the conclusions on the results obtained.
The Peru Coastal Current, sometimes called Humboldt’s Current, represents a narrow
belt of cold water which runs up the west coast of South America roughly from Valparaiso
to the Gulf of Guayaquil, the boundary of Peru and Ecuador. The current varies in
strength, ships having to reckon seriously with it at some times and in some places,
whereas at others it is so weak as to be unnoticed. The waters are generally cooler
than those of the adjoining Pacific and are often coloured green, khaki, brown, orange,
and even red, by a wealth of marine life which gives rise in the south to a whaling
industry and in the north to the richest bird population in the world and its com-
mercially valuable deposits of guano (Plates XV and XVI). The interest of the current
lies in the problems presented by its phenomena under normal and abnormal conditions
and in their underlying causes, in its connection with the Chilean and Peruvian
littoral, with the existence of saltpetre beds, and in its effects on the economic life of
the inhabitants.
In his Naturalist’s Voyage round the World Darwin (1845, p. 47) has summarized the
features of the continent of South America in the following words:
In the southern part of the continent, where the western gales, charged with moisture from the
Pacific, prevail, every island on the broken west coast, from lat. 38° to the extreme point of ‘Tierra
del Fuego, is densely covered by impenetrable forest. On the eastern side of the Cordillera, over the
same extent of latitude, where a blue sky and a fine climate prove that the atmosphere has been
deprived of its moisture by passing over the mountains, the arid plains of Patagonia support a most
scanty vegetation. In the more northern parts of the continent, within the limits of the constant
south-eastern trade wind, the eastern side is ornamented by magnificent forests; whilst the western
I-2
NOW 7 1936
110 DISCOVERY REPORTS
coast, from lat. 4° S to lat. 32° S, may be described as a desert: on this western coast, northward of
lat. 4° S, where the trade wind loses its regularity, and heavy torrents of rain fall periodically, the
shores of the Pacific, so utterly desert in Peru, assume near Capo Blanco the character of luxuriance
so celebrated at Guayaquil and Panama. Hence in the southern and northern parts of the continent,
the forest and desert occupy reversed positions with regard to the Cordillera, and these positions are
apparently determined by the direction of the prevalent winds.
These features are illustrated in Plate XIV. But for certain details of meteorology, as,
for example, the implication that trade winds traverse the Cordillera, for which the reader -
is referred to pp. 124 and 195, the description is as apt on the centenary of his visit
as on the day it was made. The Peru Coastal Current reaches its normal development
off that arid strip of the west coast described by Darwin as falling between the luxuriant
forests of Ecuador and the rank vegetation of the Patagonian Islands, that is between
the parallels of 4° S lat. and 32-40° S lat.
Under abnormal conditions a reversal of the current brings hot equatorial water
southwards along the coasts of Peru. This counter-current, usually known by the name
El Nino, is a seasonal occurrence of varying severity and happens usually in the
months of January to March. With the hot counter-current come northerly wind and
heavy rains which in some years work havoc on a coast that normally enjoys a dry climate
and where the majority of buildings are of mud (adobe). In the sea the effects are
equally disastrous. Fish and the lesser forms of life are killed by the sudden rise of
temperature and drift on to the shore in enormous quantity. Widespread putrefaction
ensues, and sulphuretted hydrogen emitted with other decomposition products blackens
the paintwork of ships lying in harbour. This has come to be called the “ Callao Painter”’,
and locally by the name of aguaje. The loss of food is at once felt by the guano birds,
which leave their rookeries. The young, deserted in their nests, are the first to perish,
but adults also die or succumb to disease with great loss to the guano industry.
HISTORICAL
Many theories have been put forward to explain the presence of cool water on the
Peruvian and Chilean coasts. Humboldt’s classic hypothesis was published in 1811
after his visit to the west coast; but his were by no means the first of the observations
about this interesting region.”
In 1543, within eleven years of Pizarro’s conquest, Zarate was sent to Peru as
Treasurer-General by order of the King of Spain, and his account of the country is
recognized as one of the most authoritative of the early records. Accuracy on points of
fact and recognition of essential problems make his geographical observations of great -
interest. They are contained in the following extract from Kerr’s translation:
It may appear difficult to some of my readers to comprehend why no rain should fall in the plain
of Peru, considering that the country is bounded along the whole of one side by the sea, where many
' Carrillo (1892) states that the counter-current is called ‘‘El Nifio” (meaning “the child’’) by local fisher-
men because it is most noticeable after Christmas.
2 The Royal Geographical Society has published an account of the earlier observations before and after
Humboldt’s time, and this forms an historical introduction to the present report.
HISTORICAL III
vapours are constantly ascending, and on the other side by a vast range of mountain which is always
enveloped in rain or snow. Those who have carefully considered this singular phenomenon, allege
that it is occasioned by the continual prevalence of a strong south-west wind all along the coast and
over the whole plain of Peru, which carries off all the vapours which rise from the sea and the land,
without allowing them to rise sufficiently high in the air to gather and fall down again in rain. From
the tops of the high mountains, these vapours are often seen far beneath on the plain in thick clouds,
while all is quite clear and serene on the mountain. By the perpetual blowing of the same wind, the
waters of the South-sea have a constant current along the coast to the northward. Others allege a
different reason for this current; saying that the water of the South-sea having only a narrow outlet
at the Straits of Magellan, which are only two leagues broad, and being there opposed by the
Atlantic Ocean, they are forced to return to the northward along the coast of Chili and Peru. This
constant wind and current render the navigation exceedingly difficult, from Panama to Peru for the
greater part of the year; so that vessels are obliged always to tack to windward against wind and
current.
The whole coast of Peru abounds in fish of various kinds, among which are great quantities of sea-
calves or seals, of several species. Beyond the river of ‘Tumbez there are no caymans or alligators,
which is supposed to be owing to the too great coolness of the sea and rivers, as these animals delight
in heat; but it is more probable that their absence from the rivers of Peru is occasioned by their great
rapidity as they usually frequent rivers that are very still.
It is also written that the conquistadores in these harbours used to cool their drinks
by hanging flasks over the side of the ship (Acosta, 1604).
The records of early navigators such as Drake and Hawkins also contain references
to the current and to the climatic and physical features of the coast, but the hazards of
life at sea when England was perennially at war with Spain must have effectually pre-
vented any attempt at scientific observation; and although Hook had designed oceano-
graphical instruments in 1662, they seem not to have been in use, in the southern
hemisphere at any rate, before Cook’s voyages. Richard Walter, writing of the west
coast during Anson’s voyage round the world in 1740, mentions specially his need of a
thermometer. He begins his discourse upon temperature anomalies by stating that
flying fish and bonito were not met south of lat. 8° S, whereas off the Brazilian coast they
extend to much higher latitudes: this he ascribed to the low temperature of the water.
After a philosophic review of many other temperature anomalies he correlates the cool
water on the west coast with the height of the Andes: in the Gulf of Panama, where the
Andes are relatively low, he points out that the water is warm, whereas off Peru, where
they are high, the water is cool. He attributes the coolness of the Peruvian climate,
then, to the snowfields on the Andes:! this and the formation of cloud has a refrigerating
effect upon the water. He ends his discourse with the hope that
as it is a subject in which mankind, especially travellers of all sorts, are very much interested, that it
were more thoroughly and accurately examined, and that all ships bound to the warmer climates
would furnish themselves with thermometers of a known fabric, and would observe them daily,
and register their observations ; for considering the turn to philosophical subjects, which has obtained
1 This view had gained currency before Walter’s time. According to Kerr (1824, XI, pp. 32-33),
Betagh writes: “‘One would expect the weather to be much hotter here; but there is no proportion
between the heat of this part of America and the same latitudes in Africa. This is owing to two causes;
that the neighbourhood of the snowy mountains diffuses a cool temperature of the air all round; and the
constant humid vapours, which are so frequent that I often expected it to rain when I first went to Lima.”
112 DISCOVERY REPORTS
in Europe, for the last four score years, it is incredible how very rarely any thing of this kind hath
been attended to.
Humboldt’s observations of 1802 indicated that the water was cooler than the air and
that the temperature rose rapidly with increasing distance from the shore. He thus
showed that the water must cool the air and not vice versa as Walter had suggested, and
in view of the northerly current and of the results obtained by Duperrey in * La Coquille’
he formulated the theory of a coastal current of Antarctic origin. Humboldt himself
publishes little upon these conclusions, but Berghaus, who had access to Humboldt’s
manuscripts, expands his thesis and adds, as corroborative evidence, the observations
made at other times of the year by Holmfeldt, Meyen and Duperrey.
At this time writers owed most of their knowledge to the French, who had equipped
three expeditions to collect scientific data. ‘La Coquille’ in 1823 under the command
of Duperrey, ‘La Bonite’ in 1836 and ‘La Vénus’ in 1837-8, constitute important
attempts at collecting knowledge. In the published results of these and other works,
most authors adhere to Humboldt’s view and Arago in 1840 added that the current
must have great depth (1780 m.), since if this cold water were to overlay warmer
water its greater density would cause it to sink. The ‘ Beagle’ visited the west coast in
1835, and although FitzRoy makes pertinent observations, neither he nor Darwin pays
much attention to ocean temperature.
Bougainville (1837) is one of the earliest to level criticism at Humboldt’s theory,
pointing out that in 1825 the surface temperatures off Valparaiso were not much lower
than those found at Lima by Humboldt. In 1844 de Tessan takes the matter further,
arriving at the important conclusion that the low temperatures are the result of up-
welling of the lower layers. In 1844 too, Maury considered application of the Law of
Deviation to ocean currents, but this and upwelling do not seem to have been related
to one another as cause and effect until the publication of Witte’s paper in 1880.
Dinklage in 1874 had nevertheless suggested that upwelling, together with a subsurface
current of compensation towards the coast, might result by aspiration from the wide-
spread westerly set caused by trade winds in the ocean at large.
Since the opening of the twentieth century the question of the Peru Current
has been taken up afresh by writers with varying views. These are discussed on pp.
189-234, and it will suffice here to mention that as regards general principles the con-
clusions of Kriimmel, Schott, Sverdrup, Vallaux and Schweigger will probably meet
with general acceptance. Vallaux (1930) and Schott have examined the evidence
critically. Schott’s work—the first two parts of which were published in Germany in
May 1931, the very month in which the ‘ William Scoresby’ began her investigations—
is the most complete account of the hydrology of this region that has yet appeared, and
it has put all future workers in his debt. The greater part of the paper is devoted to a
discussion of the intricate problems in the northern part of the area where the cooler
Peru Current converges with warmer equatorial water. Our knowledge of this interesting
region and of the Nifio Counter-current is drawn almost entirely from his work and
it is quoted frequently in the present report. For the more southerly parts of the
NOMENCLATURE OF THE CURRENT 113
current, extending for a great distance along the South American coast, he gives fewer
data: these and his conclusions are discussed on pp. 190-215.
Sverdrup (1930) and Schweigger (1931) published original observations collected
respectively in the open ocean and close to the coast, and these represent the first
attempt to collect hydrological data below the surface with modern instruments.
Schweigger’s observations were made in the upper 100 m. and include temperature,
salinity, pH and the velocity of the current; but they lack serial arrangement. The work
of the ‘Carnegie’ extended far into the ocean and traversed the eastern South Pacific in
several directions. hese observations are to some extent complementary to the work
of the ‘William Scoresby’ and are therefore of particular value to us; it will be ap-
propriate, before attention is drawn to them, to consider the nomenclature of the
currents referred to in this report.
Writers up to 1837, including Humboldt himself, give no specific name to the
currents on the west coast. Berghaus (1837, p. 572), therefore refers to it as “‘ Der Strom
kalten Wassers langs der West Kiiste von Siidamerika, geschildert von A. von Hum-
boldt”’, which on p. 584 becomes contracted to “‘peruanischen Strémung’’; and only
in a footnote does he suggest the alternative name “‘ Humboldt’s-Str6mung’”’. ‘The more
authoritative of later writers have used the geographical designation, though Humboldt’s
name came into vogue in the second half of the eighteenth century, mainly owing to the
veneration in which it was beginning to be held. Ina recent effort to revive this vogue,
Wiist (1935) not only misquotes Berghaus and Sverdrup, but also appears to mis-
construe their sense. His other arguments likewise reflect a partiality in his handling
of the evidence and are thus hard to accept.
Uncertainty of the breadth of the current, and therefore of the region to which these
names should be applied, has given rise to many expressions of opinion. In his Physzkal.
Atlas of 1839, Berghaus distinguishes a second current by the name of “‘ Mentor’s Gegen-
Drift’... It lies to the westwards of the Peruvian Coastal Current of cold water, and
flows partly towards the east; it is therefore oceanic and warm. Kerhallet (1856)
followed Berghaus and Johnstone in making the distinction of the inshore and offshore
currents, but interprets the ‘‘ Mentor Current”’ differently, regarding it as having only
northerly flow. Laughton (1870) suggested that the Mentor Current and the Peruvian
Cold Current or Humboldt’s Current were indistinguishable, and that in consequence
retention of the name Mentor Current was not justified. This view implied enormous
breadth in the Humboldt or Peru Current and that it was no longer to be regarded as a
merely coastal current. In 1931 Sverdrup took the same view, calling it the Peruvian
Current. Other writers, however, refer the names Humboldt Current and Peru
Current to a relatively narrow zone.
In view of these widely different expressions of opinion it is necessary to reconsider
the question of nomenclature in the light of conclusions reached in the present work.
The currents under discussion cover the area we recognize to-day as the eastern limb
of the South Pacific anticyclonic gyratory movement. In the following pages it is
1 Counter to the direction of the South Equatorial Current. The chart in question is dated 1837.
114 i DISCOVERY REPORTS
shown that the surface water close against the South American coast is hydrologically
different from water which may also share northerly movement hundreds of miles out
to sea, and consequently provides a distinct biological environment. There is, however,
no sharp boundary between the two waters, the one merging gradually into the other.
Moreover, from the dynamic standpoint it appears that the movement of both waters
is actuated by similar principles, only in the one the presence of the coast induces
upwelling and other modifications. In view of the emphatic differences in the character
of the inshore and offshore components, it is desirable to draw a distinction between the
two. The cool surface water close against the South American coast will be termed the
Peru Coastal Current: and for contrast, the adjacent oceanic drift which, lying to the west
of this, also seems to share northerly movement, the name Peru Oceanic Current is sug-
gested. As, however, both currents compose the eastern limb of the anticyclonic
circulation, and as no sharp boundary exists between them, they may jointly be referred
to by the name Peru Current. Such definition of the Peru Current would not be in-
consistent with the Peru Current of Schott and the Peruvian Current of Sverdrup.
The Peru Coastal Current has great variability, and counter-currents involving
southerly and easterly drift have sometimes been reported within its boundaries: not,
however, as a permanent feature, and with the exception of the Mentor Current of
Berghaus and of E/ Nino, they have not been given names. Grounds are adduced in a
subsequent section for believing that such counter-currents may form a permanent
system of inshore and offshore eddies.
THE WORK OF THE “CARNEGTE:
The cruises of the ‘Carnegie’, extending in many directions across the eastern South
Pacific, form a valuable supplement to our own observations, which had of necessity to
be near the coast. They cover the area westwards of the South American coast to the
meridian of 115° W, and from the equator to the goth parallel south, and give for the
first time a modern account of the water layers at and below the surface from which it is
possible to determine the bathymetric limits of the Peru Oceanic Current. Thus the
‘Carnegie’s’ observations, though made in 1928-9, two years before those of the ‘ William
Scoresby’, give a picture of the general oceanic conditions without which a study of the
coastal current by itself would lack perspective.
Sverdrup (1931) illustrates with salinity sections the relation between the Peru
Current and the intermediate Antarctic current (Antarctic intermediate water), which
he shows to be characteristic of the entire southern Pacific. The intermediate Antarctic
current is shown to be a layer of low salinity at about 600-1000 m., which gains in depth
and gains in salinity as it flows towards the north. The Peru Current, on the other hand,
is shown to be a surface current whose depth does not exceed 300 m., and whose flow
represents the eastern limb of an anticyclonic movement which is illustrated schemati-
cally by a figure taken from Johnstone (1923).
Sverdrup observes that three of the sections, from Sts. 40-45, 70-80, and 60-50, run
WORK OF THE ‘CARNEGIE’ 115
approximately at right angles to the Peruvian Current and may be termed cross-sections,
while two, from Sts. 50-45 and from 60~70, are almost parallel to the current and may
be called longitudinal sections. This observation may be considered open to question,
for the sections above described seem to be orientated respectively at right angles and
almost parallel to the intermediate Antarctic current, and not to the surface currents as
figured schematically. In relation to the latter, the sections tend to encircle the centre of
anticyclonic movement and in consequence to illustrate the surface current longi-
tudinally in some parts and transversely in others. The significance of these salinity
sections will therefore be better understood in relation to the Peru Current, when the
surface currents and the trend of the surface circulation have been defined for the year
in question: it will be possible then to decide the angle at which the several sections cut
across the current.
The two sections which run more or less parallel to latitude show an increase of sur-
face salinity when departing from the coast. In the more northerly of the two sections
(Sts. 40-45), this is attributed to the presence of water from the Gulf of Panama (water
of the Equatorial Counter-current), lying close to the Ecuador coast. The rate of in-
crease is, however, very slow, which suggests that the section runs very much more with
the current than across its path. Westwards of go° W long., the section may be taken
to represent the South Equatorial Current.
In the next section (Sts. 70-80) the low surface salinity inshore may indicate that the
water has welled up from the lower layers near the coast of Peru. In this latitude the
salinity increase on departure from the coast is such that the surface drift may also be
inferred to have a marked westerly component, the concentration of surface salinity at
greater distances from the coast being brought about presumably by evaporation of the
surface layers. This section, which illustrates conditions in the Peru Current at much
greater distances from land than any of our own, will be referred to in greater detail
later (Fig. 1).
The other sections show an increase of surface salinity from south to north, but the
increase is less rapid near the coast (Sts. 60-70) than further west (Sts. 60-50). More-
over, as noted above, the surface salinity is of a lower order near the coast than in the
open sea. Sverdrup suggests that this is due to a constant transport of water of low
salinity from the south, but, in view of the westerly set noted above, this impoverishment
of surface salinity near the coast may be regarded as further evidence of upwelling.
In January and February 1929 when the ‘Carnegie’ ran her line westwards of Callao
(Sts. 70-80, Fig. 1), she recorded an increase in surface salinity from just over 35 °/,.
at St. 70, at 80 miles or so offshore, to more than 36 °/,, in 105° W long. The salinity
of the intermediate Antarctic layer is about 34:5—34:6 °/,,. At the western end of the
section, that is west of 100° W long., asharp salinity gradient separates the surface water
from water below 250 m. This sharp gradient exists between the isohalines of 36-0 and
34°7 °/, and constitutes a discontinuity layer. Above this layer the water seems to be
tropical. At the eastern end of the section no discontinuity layer is present, the isohalines
increasing gradually from the low value of 34:6 °/,., in the intermediate Antarctic layer
D XIII 2
116 ; DISCOVERY, REPORTS
to 35-0 °/.. at the surface: an increase of only 0-4 °/,, in 500 m. This may be attributed
to upwelling, but the trend of isohalines between Sts. 70 and 71 should be interpreted
with caution, since conditions in the surface stratum may have altered considerably in
the three weeks which intervened between the working of these two stations (Fleming,
1930). Likewise the surface change from 35 °/,, inshore to 36-0 °/,, in the west takes
place gradually. From this section it is impossible to say where the influence of upwelled
water is no longer felt and so to ascribe positive limits to the Peru Coastal Current.
STATIONS — 60 73 78 77 76 75 Lar 7/5) 7e 7! 70
peaks 500 (000 1500 2000 2500 3000 ss00 4000 4500
360 360 _ | 38st 35.0 7
ee: — 1
ce / == T Ga47—p 348 Kae
C34
Fig. 1. Salinity section of the eastern South Pacific based on ‘Carnegie’ Sts. 70-80. The section runs
westwards of Callao. (After Sverdrup.)
The other lines run by the ‘Carnegie’ and figured by Sverdrup furnish no better
evidence on this point, but suggest that the influence of coastal upwelling is felt less
and less as distance from the coast increases, that it has no abrupt end, and is felt at
greater distances from the shore in low latitudes (off Peru) than in high latitudes (off
Chile). ‘Thus in lat. 25° S, the data figured by Sverdrup in figs. 6 and 8 give grounds
for supposing that the influence of upwelling might be felt as far as 600-700 miles
offshore: the isotherm of 15° C. for example, being found nowhere as deep within this
distance as it is at some 680 miles from the coast. In 15° S the influence of upwelled
water may be felt at 1200-1500 miles, and at 5° S, where water is travelling westwards,
its influence may be carried indefinitely.
WORK OF THE ‘WILLIAM SCORESBY’ 117
THE WORK OF THE “WILLIAM SCORESBY-
The ‘Carnegie’s’ work lay too far from the shores of Chile and Peru to shed much
light upon the vexed questions of the Coastal Current. The phenomena of major
interest, and those around which most discussion has centred, are to be found on the
tracks of coasting steamers and on the grounds frequented by fishermen. Examination
of the surface stratum and of the lower layers, not only in this zone, but as far into the
ocean as circumstances would permit, was the main purpose of the present survey. The
present report, essentially preliminary, is based on the observations made by the author
and his colleagues on board the R.R.S. ‘ William Scoresby’, and is confined to an account
of conditions in the upper layers.
In 1931 ascheme of investigation was prepared by the Discovery Committee with the
assistance of the Hydrographic Department of the Admiralty. Owing, however, to
our limited knowledge of the hydrological conditions on the coast, the programme was
kept flexible, and execution of the work was to a large extent guided by the results
obtained as we went along. Thermometer records were plotted on blank charts hour by
hour as collected, and the position of stations and the ship’s course were adjusted as the
work developed. Thus we gained a bird’s eye view of the general conditions as we
worked up the coast. This report is concerned with the layers between 400 m. and the
surface with especial reference to their temperature and salinity, to the effect of wind
upon water movement, and to the consequent effect on the phosphate content of the
surface and on the life in the sea.
ACKNOWLEDGMENTS
The analysis of water samples for their phosphate content was carried out by my
colleague Mr A. H. Laurie, and the results as plotted by him are illustrated in Figs.
40 and 54-61. All the samples were examined within 3-4 days of collection and many
within a few hours while still at sea. The consistency of the major differences in the
phosphate distribution suggests that they are significant but the conditions of work
make a considerable, but undetermined, error probable. Mr G. W. Rayner, who
joined the ship towards the latter end of the survey, contributed to the work and has
made a preliminary examination of the phytoplankton collections (pp. 178-181). The
track of the ship, illustrated in Figs. 5-13, 70 and 71, was drawn by Mr F. E. C. Davies,
who performed the duties of navigating officer and was in command of the ship during
her work off Peru. The meteorological data are extracted from the deck log book, where
they were entered by the officers of the watch. In making acknowledgment of the work
of colleagues our thanks are also due to Lieut. Rafael Torrico of the Peruvian Navy,
who was seconded to the ship as liaison officer and who contributed very greatly to
the success of our operations.
It has been our good fortune to have the help of Mr D. J. Matthews of the Hydro-
graphic Department of the Admiralty, who assisted both in planning the research and
2-2
118 i DISCOVERY REPORTS
ECUADOR _
Santa Llena
} WS 715-718, see Aig Th
Ce
cana 4.
jn" WS. 674 - 682, see Fig 13°
PERU
PACIFIC
WS. 663- 671, WS. 728-733
Callao We 661,662,672, 684685, =
OCEAN
Fig. 2. Track chart of R.R.S. ‘William Scoresby’, June to August 1931. Reference to Figures in which the ship’s
movement is shown in detail is made opposite each line of stations.
TRACK OF R.R.S. ‘WILLIAM SCORESBY’ 119
Arica
WS. 639-643 . | Cave Carranza
see Figit ; ‘WS 591-600
An tr
He aes!
see Fig 9g
Tat Paral
| CHILE
= Caldera
WS.613-620
! See figs.
PATAGONIA
Fig. 3. Track chart of R.R.S. ‘William Scoresby’, May to June and August to September 1931. Reference to
Figures in which the ship’s movement is shown in detail is made opposite each line of stations.
120 DISCOVERY REPORTS
in his continued interest in the progress of the work; to him we owe a translation of
Schott’s recent writings. I am indebted to Miss D. M. E. Wilson for titrating the
water samples and to Miss E. C. Humphreys for the care she has taken in preparing
the figures for reproduction. Among the many others who have helped I wish to thank
especially Dr C. E. P. Brooks and Dr J. A. Fleming, Mr E. W. Barlow, Mr G. E. R.
Deacon, Dr T. J. Hart, Mr G. R. Crone, and Miss E. I. Holme. In particular, | am
indebted to Dr S. W. Kemp, whose help and sympathy have greatly facilitated the
execution of the work.
The Carnegie Institution of Washington has kindly supplied manuscript data of the
‘Carnegie’s’ cruises in the Pacific; the Admiralty and the Royal Geographical Society
have extended library facilities, and the Meteorological Office has loaned daily weather
bulletins of Chilean Meteorological Stations.
EQUIPMENT AND METHODS
Winter months were allotted to the survey because the R.R.S. ‘ William Scoresby’ was
due to work in the south during the southern summer; there was otherwise no special
design in choice of season, though it was hoped that by compressing the work into a
relatively short space of time symmetrically arranged about the winter solstice
uniformity in weather conditions and temperature might be secured.
The ship at first under the executive command of Lt.-Comdr. J. C. C. Irving, R.N.
(Retd), and later of Mr F. E. C. Davies, cruised over the whole area from the Gulf
of Pefias to Santa Elena in Ecuador. On the northward journey from May 18 to July
26 she carried out the greater part of her programme, working eleven lines of stations
across the path of the current in the space of two months (Figs. 2 and 3). The return
journey southward was made the occasion for an additional line off Santa Elena and
for working oceanic stations in a meridional direction and for repeating the observa-
tions made off Callao in July. The ship steamed on a direct course from the Callao line
to Pichidanque Bay.
Two objects were kept in view in planning the positions of stations: firstly the
securing of a sufficient number of observations to provide data for hydrological sections,
and secondly to span the breadth of the current. The first station of each line was
placed as close as possible to the shore. Owing to isothermal irregularity the stations
over shallow water were placed close together, but those following, over deep water,
had to be placed at progressively greater intervals. Each line was terminated when
the isotherms beneath the surface showed a horizontal tendency. ‘This point on the
line, dictated by considerations of economy, might or might not approximate to the
western boundary of the Peru Coastal Current, but it always lies between the cooler
inshore waters, where upwelling and coastal influences cause isothermal irregularity, and
the open ocean, where the surface water is warmer and where the temperature shows
a condition of comparative stability.
When running from one station to another on the same line, the ship was usually
WIND RECORDS 121
steered in a direction normal to the coast; but she was allowed to drift off this course
according to the strength of wind and current in a direction parallel to the coast. The
differences between the observed and the dead reckoning positions of the stations are
consequently a measure of this drift: and the track chart is therefore a graphic repre-
sentation of the combined effects of wind, tide and current upon the ship’s course. By
this method their combined force is more easily assessed than it would have been had
an attempt been made to place the stations on a straight line.
At each station, where depth allowed, observations were made at the following depths:
surface, 10, 20, 30, 40, 50, 60, 80, 100, 150, 200, 300, 400, 600, 800, 1000, 1500, 2000,
2500 and so on at 500 m. intervals to the bottom. When running outward from the
shore into deep water, soundings were made at alternate stations: on this series of
stations hydrological observations were made all the way to the bottom; on the alter-
native series, the hydrological observations were made no deeper than the depth of the
preceding sounding.
The work included determinations of temperature, salinity, phosphate and oxygen,
and nets of different mesh were fished vertically from 100 to o m. and obliquely from
250 to 100m. and 100 to om. to sample the plant and animal constituents of the
plankton. A complete schedule of these observations will be published in due course
as a Station List in the present series. When the ship was under steam from one station
to another a routine of four-hourly observations of surface temperature and salinity was
performed; but additional surface temperatures were taken as occasion demanded, and
here the want of a continuous thermograph was acutely felt. Phosphate was estimated
by Deniges’ coeruleomolybdic method as modified by Atkins (1923).
The equipment used on this survey was essentially similar to that described by Kemp
and Hardy (1929). Water samples from depths not exceeding 400 m. were collected
with the Nansen-Pettersson insulating water bottle, while at greater depths the Ekman
reversing water bottle was used.
Throughout this report, figures referring to the same locality are printed as far as
possible on comparable pages. As far as possible they have also been reduced to a
common scale. Thus track charts are not only comparable with one another, but their
scale has been adjusted to fit the scale in miles of the various sections of temperature,
salinity and phosphate, and of the curves illustrated in Figs. 29 and 30. Exceptions are
furnished by Figs. 2, 3, 28, 35, 42 and 51.
WIND
Records of wind, based on personal estimates of its direction and force, were kept
every four hours by the officers of the watch; and in addition we have had access to
daily weather bulletins issued by the Chilean Meteorological Office. The data may
conveniently be considered under three heads: observations on board ship at a distance
of more than 50 miles from land; observations within 50 miles of land; and those of
Chilean coastal stations. The former two are plotted in Fig. 4 separately as residuals
122 DISCOVERY REPORTS
of observations between every two degrees of latitude: the last separately for each
station as the residual of the observations available for a fortnight prior to our arrival
off the coastal strip in question.
Reduction of wind forces to residuals followed the normal practice of vector averaging :
the directional velocities expressed as miles per hour were first resolved along the
cardinal points of the compass; these were summed and reconverted into an aggregate
resultant which was then divided by the original number of observations.
This method of reducing data gives a working idea of wind conditions, even though
the number of observations represented by each arrow in Fig. 4 may vary according
to the length of time spent by the ship off each stretch of coast. In certain instances,
when a rapid change in wind was followed within a few hours by changes in hydrological
conditions, the data before and after the change have been plotted separately. This has
been done off Antofagasta and off northern Peru where the ship covered the same ground
two or three times, and the data on the voyage northward in May to July have been plotted
independently of the voyage southward in August to September.
Specific instances of the effect of wind upon the ship’s drift and upon upwelling are
discussed later ; here it may be well to take a general view of the winds prevailing on the
west coast at the time of our visit.
Fig. 4 will show the existence of natural regions in each of which the majority of
winds usually blow in a set direction. We may differentiate between the following:
south of lat. 38° S winds are irregular in force and direction in the months of both May
and September. This region lies in the circumpolar tract of the ‘‘ westerlies”, known
also as the “roaring forties’’. North of 38° S winds are more regular. They appear to
have least force over land and most far out to sea. The weakest winds over the coast are
naturally least certain in direction, but those immediately offshore blow almost without
exception parallel to the coast, i.e. they are southerly winds off Chile and south-easterly
off Peru.
Farther from the Chilean coast, in August at any rate, the winds showed a departure
from the coast-line direction: they veered from southerly inshore to south-easterly as the
distance from land increased. These winds between the parallels of 32 and 4° S lie in
the path of the south-east trades, and it would appear that while the south-east winds
off Peru and far out to sea off Chile may be classed as normal trades, the coastal winds
represent a departure from them. Such a distribution of winds is normal for the circula-
tion in the eastern South Pacific; Brooks (1929) thus summarizes the position as it is
understood at the present day:
The centre of the South Pacific anticyclone lies off the coast in the latitude of 30° S, and pressure
is highest in this latitude, decreasing slowly northward and more rapidly southward. The northern
part of the region as far as 30° S is throughout the year under the influence of the south-east trade
winds, which cross the equator and blow into the Gulf of Panama as south-westerly winds. South
of 30° the winds are south-westerly, rapidly becoming westerly and increasing greatly in force as the
“roaring forties”’ are approached... .
From the belt of high pressure in about 30° S pressure decreases steadily southward, very rapidly
between about 40° and 50°. Here strong westerly winds prevail throughout the year, often of gale
St Felix
” “St Ambrose
- Fig. 4. Winds recorded during the period of survey. Left, August and September; centre, May, June and July (July
12-17 excepted); right, July 12-30. The arrows represent the residual wind (expressed as mean vectors); in the open
sea and in the coastal zone, for observations in every two degrees of latitude; and at the Chilean meteorological stations
for observations during a fortnight prior to the ship’s arrival (see text and Appendices IV and V).
124 ; DISCOVERY REPORTS
force, and this region has received the name of the ‘roaring forties’’. Here the depressions almost
invariably pass to the southward and merely cause a variation of the wind from south-west to north-
west. South of 50° S barometric depressions travel in an eternal procession from west to east, with
their centres sometimes in about 50° S, sometimes near the Antarctic circle. On the northern sides
of these depressions the winds are westerly, and on their southern sides easterly, hence along the
trough of lowest pressure in 60° S, where the depressions are most frequent, the winds are very
variable.
The departure of the coastal winds from directions more typically those of the trade
winds is a constant feature of the coast and was noted by Dampier as early as 1684.
It may be regarded as evidence of the fact that the surface air circulation of the Pacific,
which reaches a total height of little more than 5000-6000 ft., is cut off from that of the
Atlantic by the lofty barrier of the Andes. This has been suggested earlier by Mossman
(1909):
There can be little doubt that the influence of the mountain chain of the Andes in modifying the
general circulation of the air is considerable, causing the coastal winds to conform to the shores of
the littoral, and to blow parallel with the main axis of the Andean Cordilleras.
The suggestion made earlier, that the division between the areas of high and low
pressure lay at the time of our survey in 38° S, is no more than approximation. Moss-
man has been able to give figures to show that in normal conditions the division is
situated close to the 41° parallel.
Bowman (1916) draws attention to a wind of local importance in the sea-breeze which
he describes as ‘“‘without exception the most important meteorological feature of the
Peruvian coast’; and the data he illustrates shows that this effect is conspicuous at least
as far south as Iquique on the Chilean coast. Off Callao, diurnal periodicity was de-
scribed at least as early as 1806 (Unanue). While the ship’s movements prevented the
collection of data in sufficient detail to illustrate the significance of this sea-breeze,
our observations, and especially at Pisco (see Appendix IV, p. 259), are believed to lend
some support to its existence. Bowman gives the following description of it:
Several graphic representations are appended to show the dominance of the sea-breeze (see wind
roses for Callao, Mollendo, Arica, and Iquique), but interest in the phenomenon is far from being
confined to the theoretical. Everywhere along the coast the virazon, as the sea-breeze is called in
contradistinction to the terral or land-breeze, enters deeply into the affairs of human life. According
to its strength it aids or hinders shipping; sailing boats may enter port on it or it may be so violent,
as, for example, it commonly is at Pisco, that cargo cannot be loaded or unloaded during the after-
noon. On the nitrate pampa of northern Chile (20-25° S) it not infrequently breaks with a roar that
heralds its coming an hour in advance. In the Majes Valley (12° S) it blows gustily for a half-hour
and about noon (often by eleven o’clock) it settles down to an uncomfortable gale. For an hour or
two before the sea-breeze begins the air is hot and stifling, and dust clouds hover about the traveller.
The maximum temperature is attained at this time and not around 2.00 p.m. as is normally the case.
Yet so boisterous is the noon wind that the labourers time their siesta by it, and not by the high tem-
peratures of earlier hours. In the afternoon it settles down to a steady, comfortable, and dustless
wind, and by nightfall the air is once more calm.
The possible influence of this factor in relation to the hydrology of the coastal waters
is considered on pp. 210, 232 and 233.
CURRENT AND DRIFT OF THE SHIP 125
CURRENT AND: DRIFT OF THE SHIP
It was essential to the efficacy of our observations that the ship should cover long
distances in the shortest possible time, and we were thus unable to include detailed
current measurements in our programme; we were, however, able to record the com-
bined effects of wind and current on the drift of the ship in a direction parallel with the
coast which is here a component of major interest.
As explained on p. 120, the ship was steered regardless of lateral drift when steaming
from one station to another in a direction normal to the coast. The track chart is there-
fore a graphic representation of the resultant effect upon the ship’s course, of the com-
ponents parallel to the coast, of wind, tide and current. The amount of this drift off
different parts of the coast has been summarized in Table I. The drift is expressed in
miles per day and is calculated from positions that had been fixed by Mr Davies, the
ship’s navigator, from observations of sun, stars or land bearings: dead reckoning
positions have not been used in this calculation.
Northerly drift was experienced at irregular intervals over the whole surveyed region,
but southerly drift only inshore and far out to sea off Peru; frequently no drift was
noticeable. We may inquire whether it is possible to find out from any of these observa-
tions how much of the drift was referable to current and how much to wind.
On approaching Cape Carranza from the southward no wind was met, but a south-
westerly set of 3 knots, possibly tidal, was recorded close inshore: the ship does not seem
to have been under its influence when farther from shore between Sts. WS 593 and 596
(Fig. 7). The southerly drift experienced from 24 to 44 miles is almost certainly the
result of northerly winds reaching force 4. Upon a change of wind to east-south-east at
St. WS 599 the southerly drift changed to northerly. The conclusion is that there can
have been no appreciable current off Cape Carranza.
On the second line, off Pichidanque Bay, no drift at all was recorded on the run
westward, from which we can infer there was no current (Fig. 6). The northerly leeway
experienced between Sts. WS 607 and 610 may be due to southerly wind, which during
Sts. WS 608 and 609 reached a force of 5—6. These observations are of particular interest
in showing that a mean drift of 20 miles a day can result from the direct action of
winds in a region where before their advent no flow of surface water was apparent.
The track chart (Fig. 5) shows that the east and west courses off Caldera were sub-
ject to varying amounts of northerly and southerly drift, and this may be loosely related
to changes of wind. 'This may be seen in Fig. 8, in which the amounts of northerly and
southerly drift are plotted against wind records during the period from noon on June 4
to noon on June 6. The distance from shore at which the observations were made is also
indicated. Northerly drift usually attended southerly wind and southerly drift usually
attended northerly wind, but a strong southerly drift against the wind within 2 miles of
the coast is evidence of a counter-current inshore. At 11-27 miles from shore northerly
-drift was recorded during calm weather following a period of northerly winds: while this
3-2
Fig. 5. Caldera. Track of R.R.S. ‘William Scoresby’, June 4-6. Courses set east and west, except on the
limb immediately before St. WS 613. St. WS 612 was revisited after completion of St. WS 620. In this and
the following charts, the track of the ship is shown as a thin broken line, and the surface isotherms as heavier
continuous lines.
Fig. 6. Pichidanque Bay. Track of the ship, May 28-30. After St. WS 602 course set 270°;
after St. WS 607 course set ogo”.
Fig. 7. Cape Carranza. Track of the ship, May 18-20. After St. WS 593 course set 270°;
after St. WS 601 course set 280°.
CURRENT AND DRIFT OF THE SHIP 127
HOUR 12:00 0600 00°00 1800 1200 06°00 aan 1800
10
6
2
O jSSE 3 | SW 3] SxE 3] SW3
2
&
DATE 6- Vi-1931 | S-Vi-1s31 4-Vi- 1331 |
1200
4
NORTHERLY ORIFT
MILES PER OAY
SOUTHERLY DRIFT
Brno 27-21 | 27-11 | 35-5 [s-2 2 i] 54-8 |
Fig. 8. Drift of the ship in a north and south direction, from noon on June 4 to noon on June 6, illustrated
diagrammatically from right to left. The data are given in Tables I and Appendix IV. The northerly drift
from noon on June 4 to 0507 on June 5 includes the time spent on St. WS 612, and the passage to within 8
miles of land (see Fig. 5); the subsequent drift, alternately south and north, took place while Sts. WS 613-620
were being worked. Four-hourly records of wind are given in the centre of the diagram, while below is
appended the distance from land at which each of the observations was made.
might be regarded as evidence of northerly current we believe the data too few for
definite information.
On the journey out from Antofagasta the wind blew at first east, and then un-
remittingly from the south with force 4, which increased to 5 from south-south-west
in the open sea; during some 36 hours from Sts. WS 622-630, the ship drifted 11 miles
to the northward, i.e. a mean drift of 8 miles a day. According to the track chart,
however, the greater part of the drift occurred within the coastal 15 miles, and as in
addition the drift had an appreciable westerly component, the mean rate exceeded
12 miles a day. Since the greater drift accompanied the lesser wind, some may be
ascribed to currents.
The return journey commenced with moderation from force 5 to 2 in the southerly
wind which later changed direction to the north; in spite of this the ship was carried in
a north-easterly direction as may be inferred from the positions at the beginning and end
of St. WS 630, during which the ship was drifting for 12 hours (Fig. 9 and see p. 145).
A heavy counter-current was met inshore off Bahia Herradura.
On a later page, the surface drift off Antofagasta will be related to changes of surface
temperature: it is therefore of particular interest that the positions of stations in this
locality (Fig. 9) have been fixed with exceptional accuracy: those of the first seven
(Sts. WS 622-628) and the last six (Sts. WS 630-635) by cross-bearings on land and
that of St. WS 629 by observations on a sunny day; the ship’s track is in consequence
a faithful record of her drift, but of the relative velocity of this drift on different points
of this line, it is misleading because there is no indication of the time spent on any
one part of the line.
Winds inshore off Arica amounted to light airs, yet a north-westerly drift of 48
miles a day was noted, which must be due to inshore current (Fig. 11).
The amount of drift and set experienced at various points along the San Juan line
of stations is of interest (Fig. 11). A strong wind from the south-east blew for almost
the whole period. Close to the shore its force attained 6-7 and drifted the ship to
128
DISCOVERY REPORTS
Table I. Showing drift recorded by R.R.S. ‘William Scoresby’
Drift observed
A Distance
Position Date feornshore ae. Miles
Direction
per day
Santa Elena 31. Vii-I. Vill. 31 0-50 — °
Gulf of Guayaquil:
lat. 2-3° S I. Vill. 31 80 ENE 24
50 NW 34
lat. 3-4° S 2. Vill. 31 go NW 31
Capo Blanco S25e vila 0-2°5 ) 58
215-21 N 18-24
Punta Aguja 21-23. Vil. 31 I-33 N 36
33-100 N 6
100-171 SW 14
171-204 — fe)
Lobos Islands 17-18. Vil. 31 6-33 NW x N 36
33-54 NEN 24
86 SW 36
128 WwW 30
Guanape Islands IO. Vil. 31 8-27 NW 12
Callao 20-21. Vill. 31 6-19 = fo)
19-155 N 3
I-2. Vil. 31 6-24 — )
24-103 N 17
San Juan 23-24. Vi. 31 64-84 NW 2
84-152 SE 6
22-23. Vi. 31 2-13°5 NW 24
13°5-99 NW 10
gg-152 NW 19
Arica* 1Q. Vi. 31 4-11 NW 48
Antofagasta g-I0. Vi. 31 O-1'5 S 38
1°5—6°5 — fo)
6-5-17 Nt 24
17-46 Nt 8
8-9. Vi. 31 O-14'5 Nf II
14°5-46 N 6
Caldera 5-6. vi. 31 1-2 S 21
2-5 N 8
5-13°5 s 14
11-27 N T4
21-27 S 3
: 4-5. Vi. 31 8-54 N II
Pichidanque Bay 29-30. V. 31 25-129 N 20
28-29. V. 31 0-129 = )
Cape Carranza 18-19. V. 31 4°5-24 = °
24-44 5 14
44-64 N 10
* Dead reckoning indicates negligible drift at >16 miles.
+ Plus considerable easterly component.
{ Plus westerly component.
CURRENT AND DRIFT OF THE SHIP 129
leeward of her outward course which was maintained at 224°. During her run from
25 to 100 miles from the coast the force of
the wind and drift eased but thereafter in-
creased again, rising to force 5 and increasing
also the amount of her drift on the end of the
line. On her return run ona course of 44° from
Sts. WS 653 to 657, the force of the wind | | .
lessened gradually from 5 to 4:5, and with it the |
drift from 12 miles a day to zero. When the
wind decreased further to force 4, the ship
drifted against it. It appears therefore that
during the 58 hours from Sts. WS 647 to 657,
while the ship’s course was maintained at 224° —
on the outward and 44° on the inward run, the
total drift including leeway amounts to no more | |
than 8 miles a day. In similar wind conditions |
off Pichidanque Bay where there was no ob- | }
servable current, the recorded amount of
drift was more than twice as great. It seems
necessary therefore off San Juan to postulate an
offshore current flowing south-east against the
wind,
Current was shown to be absent within
24 miles of the Callao coast by observa-
tions of discoloured water at the Palominos =
Island control stations and by the well-fixed Fig. 9. Antofagasta. Track of R.R.S. ‘William
positions of Sts. WS 663-666 (Fig. 10). At Scoresby’, June 7-10. St. WS 630 was worked
mrheaadlictinccs fromthe shore a.leeward between the two positions shown. Course set
5 x _ 270° from St. WS 622 and ogo® from St.
drift of 20 miles in the space of 28 hours (the ws 629.
period between Sts. WS 666 and 671) accords
with the drift experienced on other occasions. Observations of discoloured water off
Palominos Island were first made on June 26, when a patch cinnamon rufous in colour
lay south of San Lorenzo Island, its northern margin coming to an abrupt end opposite
Palominos Island (Plate XVI, figs. 7 and 8). The boundary line between the cinnamon
rufous and the clear water of porcelain blue northwards formed so striking a line of
demarcation that it was kept under observation for several days. It was revisited on
July 1 and 15, and in that time, although it had grown less distinct, it had not drifted
farther northwards than the northern end of San Lorenzo, a distance of some 4 miles.
When observations were repeated in August, current was again insignificant.
Off the Guafiape Islands northerly drift amounted to 12 miles a day, rather more
than would be accounted for by the southerly wind of force 1-2 which prevailed at the
time, and some of this must therefore be attributed to current (Fig. 13).
s
Fig. 10. Track of R.R.S. ‘William Scoresby’ off Callao. Sts. WS 663-671 were carried out on July 1-3,
Sts. WS 728-734 on August 20-21. Isotherms in July are shown as continuous, in August as broken lines.
After Sts. WS 663 and 728 course set 242°, after St. WS 668 course set 062°. Stations listed on the site of
WS 662 are control Stations.
Fig. 11. San Juan. Track of the ship, June 22-24. Inset left: stations in Pisco Harbour (June 25). After
St. WS 647 course set 224°, after St. WS 653 course set 044°. Inset right: track of the ship off Arica, June
19-20. After St. WS 640 course set 238°.
CURRENT AND DRIFT OF THE SHIP 131
When shaping courses to take observations midway between the Lobos de Afuera
and the Lobos de ‘Tierra, allowance was made as far as possible for the effects of drift
and set which were pronounced on all parts of the line (Fig. 12). At 116 miles offshore
the drift of 30 miles a day was almost due westerly (264°): at 78 miles offshore 36 miles
a day south-westerly (213°): to the westwards of the Lobos de Afuera (45 miles from
the mainland) the drift was north-easterly (032°) with a velocity of 24 miles a day, and
between the two archipelagoes and at distances of less than 20 miles from the mainland
the drift was north-westerly with a velocity of 36 miles a day. The winds during this
time were on the whole light, and drift, at any rate inshore, must be ascribed very
largely to surface currents. This accords with the traditional records of current off this
stretch of the coast (p. 190).
A considerable current affected the ship within 33 miles of Punta Aguja. The total
drift northwards was 18 miles in 12 hours. Ina slightly stronger wind off Pichidanque
Bay where there was no current the ship had drifted at 20 miles a day. Allowance for
wind off Punta Aguja would thus leave a clear balance of 16 miles a day which can
be attributed to the northerly current. Between 100 and 171 miles offshore a south-
westerly current appears to have drifted the ship at 14 miles a day against a wind
force 1-2 from south-east and south-south-west.
The currents off Capo Blanco were complicated by the intrusion along the coast
of hot water of low salinity southwards from the Gulf of Guayaquil and the coast of
Ecuador. Local currents were very strong: while the ship was working a station
in the hot water inshore a south wind blew with a force of 5-6 strong enough to give
her a northward leeway drift of some 18 miles a day. But against the wind a surface
current raced southwards at an estimated 48-96 miles a day, and overcoming the effect
of the strong wind, carried the ship southwards at 41 miles a day. Farther from the
shore the current weakened (Fig. 70).
Off the Gulf of Guayaquil itself three records indicate that surface movement is
considerable (see Table I): but within 50 miles of Santa Elena none was recorded.
These data suggest that the ship’s drift has been caused to a great extent by wind.
Estimations of northerly drift resulting from the action of current alone indicate that
it had a velocity of 16 miles a day off Punta Aguja and of 48 miles a day off Arica;
considerable current was noted off the Lobos Islands but less off the Guanfape
Islands, Antofagasta and Caldera. Off Cape Carranza, Pichidanque Bay, Callao and
Santa Elena the ship’s drift seemed to be entirely due to windage. Off Capo Blanco,
San Juan, northwards of Antofagasta and Caldera, southerly currents were also
recorded.
Inferences of a general character may be made by averaging the drift at different
distances from the shore. The mean drift off Chile and Peru separately and off the west
coast as a whole is illustrated in Figs. 14 and 15 ; the first gives the mean gross drift in both
northerly and southerly directions ; the second gives the mean residual drift either north
or south after subtracting the lesser from the greater. A key showing the number of
observations averaged at different distances from the shore is given beside each graph.
D XIII 4
Fig. 12. Track of R.R.S. ‘William Scoresby’ off the Lobos Islands, July 17-20; and off Punta Aguja, July 21-23.
Inset: Sts. WS 704~707 off Punta Aguja. After St. WS 696 course set 270°.
Track of the ship, July 9-11; St. WS 686 was carried out on July 17. The
distribution of surface isotherms is shown in Fig. 34. After St. WS 678, course set 2384°.
Fig. 13. Guafiape Islands.
CURRENT AND DRIFT OF THE SHIP 133
The drift in a direction parallel to the coast was found on the whole to be weak.
It was greater inshore where it had a mean velocity of 10-12 miles a day, than at a dis-
tance of 100-130 miles where the mean velocity in a direction parallel to the coast was
MILES FROM COAST
100
200 150 50
i 1 2
NORTH PERU [| ee ae PERU {
{ Ese a I 4=5 [6 [718 [a
20
iS
10
5%
Na
Oo w
ao
Sig
10>
i)
20
25
[CHICE—PICHIDANGQUE BAY ONLY] CHILE
2 Bl 4 6-7 4
-15
ox
oO
<&
w
a
rH}
=
=
NORTH PERU | PERU } - CHILE AND PERU __
1 (fez 6-3 10-15 a |
cis
+ 10
es
ow cw
MILES PER DAY
ro)
15
Fig. 14. Diagram illustrating the ratio of northerly to
southerly drift (respectively above and below base-line)
at different distances from the coast. The data are plotted
separately for Peru (uppermost) and for Chile (centre);
and in combination for the west coast as a whole (lower-
most). The drift, expressed as miles per day, represents
the mean drift of the ship in a direction parallel to the
coast; and is computed by dividing separately the total
amounts of the drift in each direction by the total number
of observations in both directions.
MILES FROM COAST '
200 150 100 50
1 1
NORTH PERU PERU
T 4 I 4-5 L_6 17] 8 fP2
MILES PER DAY
CHILE_PICHIDANQUE BAY ONLY, CHILE
2 4 6-7
CHILE AND PERU
6-3 I 10=15
4
E NORTH PERU [PERU J
1 | 1
Sat aoe Be
ow
T
un
MILES PER DAY
Fig. 15. Diagram illustrating the mean residual drift
at different distances from the coast. The drift of the
ship in a direction parallel to the coast is expressed as
miles per day and is computed by dividing the difference
between total drift towards the north and towards the
south, by the total number of observations. The data are
plotted separately for Peru (uppermost) and for Chile
(centre); and in combination for the west coast as a whole
(lowermost).
only 34 miles a day. There was no sudden change from the zone of heavier drift to
that of lesser drift, but the mean values over the whole coast showed a slow reduction
with increasing distance from shore. Observations on drift at distances beyond 130
miles were made on only four lines, and these being off Peru are insufficient to allow
of generalizations.
134 DISCOVERY REPORTS
TEMPERATURE
Figs. 16 and 17 show that surface isotherms are generally parallel to the coast, thereby
emphasizing the contrast between inshore and offshore temperatures: the temperature
off southern Chile is less than off northern Peru, and isotherms consequently slant
gradually towards the coast. If we sail out to sea across the current we find that the
temperature of the water rises as the distance from land increases, and at 50-100 miles
or more it is higher by 1-5°. During the present survey this rise varied at every point
along the coast as shown by the irregularity of the curves in Figs. 29 and 30, and the
positions of isotherms vary greatly at different times and in different localities.
Off the Peruvian coast lay a wedge of warmer water, whose temperature was higher
than that of adjoining waters east and west. It shows as a dome-shaped hump in the
graphs of surface temperature (Fig. 30) for the Lobos Islands, the Guanape Islands,
Callao, San Juan, and possibly also for Arica (Fig. 29); off San Juan, off Callao in
July, and off Callao in August, this warmer water had a breadth of about 50 miles at
distances offshore of respectively 100-150, 25-75, and 10-60 miles (p. 148 et sqq.). On
these lines the observations extend beyond the warm water to cool temperatures, but
the Guanape Islands line terminated before the warm water was crossed. The warm-
water wedge lies therefore on the edge of the area examined, and the observations may
be too few fully to determine its character. In Fig. 16 the available data are con-
toured as straightforwardly as possible. An alternative if not more attractive theory
is discussed on p. 192.
The difference between the temperature of the warm-water wedge and that of adjoining
oceanic water to the west was small but never indistinguishable between the parallels of
17 and 6° S, from June 22 to August 20. Off San Juan this warmer water seemed dif-
ferent from the cooler surrounding water, and its fauna contained species such as
flying fish which were never found in the cooler waters. Here also the wedge appeared
to differ in its movement (see p. 129). In the northern part of the region the wedge was
relatively less warm than surrounding water but could still be recognized. Its distance
from the shore may be placed at 50 miles off the Guanape Islands, 140 miles from the
Lobos Islands, and 180 miles off Punta Aguja. Its western margin in these latitudes was
ragged, irregular and ill-defined, and its nature as a distinct body of water less well
established. Off Punta Aguja its western margin (the isotherm of 20° C.) left the area
of our investigations.
The northern boundary of the Peru Current off Capo Blanco is clearly discernible,
the surface temperature showing a reversal of the conditions found farther south. Off
Capo Blanco the hottest water lay near the coast, but in the space of 22 miles the surface
temperature dropped to the level formerly found inshore off Punta Aguja. The Peru
Current, hitherto coastal, seems to have swung out to sea, and cutting across the line of
stations off Capo Blanco seems to have been pursuing a west-north-westerly course
towards the Galapagos Islands; inshore a tongue of hot water projected southwards
from the Gulf of Guayaquil.
TEMPERATURE 135
In the following pages the isotherms in vertical section and in surface plan will be
examined with a view to tracing correlations between them and such factors as wind,
surface drift, salinity, phosphate and plankton distribution, and the colour of the water.
45-35°S: CAPE CARRANZA
The climate is temperate and the southerly regions are drenched in heavy rainfall,
the surface salinity being thereby reduced (see Fig. 18 and p. 159). At the surface the
isotherm of 12° C. followed the ship’s track from south to north for as much as 600
miles; and beneath the surface, similar thermal uniformity is shown, isotherms being
spaced widely apart and the temperature sinking but 5° through the depth of 400 m.:
salinity shows, however, that the water is distinctly layered (pp. 159-163).
Off Cape Carranza the water was, in appearance, actively welling up, but in view of
the fact that no drift was noticed at the surface, and of the fact that the ship enjoyed calm
weather, the wind being in the north, this appearance of upwelling may bea relic of earlier
activity. Comparable conditions in other localities will later be seen to suggest a reversal
of upwelling, and the possibility should be borne in mind that subsidence of the cool
surface water may have been in progress off Cape Carranza at the time of our visit.
Upwelling is shown to have been extensive for some considerable time in the past by
the high content of phosphate and of plankton of the upper layers (pp. 182 and 184).
The surface temperature rose steadily from 11-45° C. inshore to 13-57° C. at 58 miles
offshore, after which the rise was less, reaching 13-65° C. at 83 miles offshore (Fig. 29).
If the inshore water at this time were really subsiding as suggested, the lowermost of the
isotherms and isohalines formerly showing upward movement might at the time of our
visit have regained horizontal stratification. If this were so, the sections illustrated in
Figs. 18 and 19 would no longer indicate the depth previously involved in upwelling.
After the light airs that had prevailed up to St. WS 596, a north-north-east wind arose reaching
force 4, and this coincided with warm water at the surface at St. WS 597. This suggests at first that
wind from the north had driven warmer water southwards, but the same wind persisted at St. WS 598
where cooler water was again met with.
45-30° S: PICHIDANQUE BAY
Over this 300-mile stretch of coast the water becomes rapidly warmer and the weather
as recorded at Valparaiso was calm; surface isotherms instead of running parallel to the
coast slant steeply towards it.
At the end of May, Pichidanque Bay was still enjoying a period of calm that had been
in existence for some considerable time. Warming up of the surface layers had led to a
mean inshore temperature of about 14° C., while a temperature of 11-45° C., found at
the surface at Cape Carranza, was here at 40-70 m. depth. A poverty of phytoplankton
and zooplankton such as was not found at any other locality examined and extreme
depletion of phosphate are signs that for many weeks past the upper layers cannot have
been replenished with nutrient salts, or at any rate only on a very modest scale.
Sections (Figs. 20 and 21) indicate that mild upwelling had been taking place, for the
isotherms and isohalines curve slightly upwards near the coast, yet on our arrival on
136 : DISCOVERY REPORTS
Fig. 16. Distribution of surface isotherms off Peru, June to August, 1931.
placed on the same data in Fig. 63.
An alternative construction is
137
TEMPERATURE
3
Mer)
J
Fig. 17. Distribution of surface isotherms off Chile, May to June, 1931.
STATION NUMBERS —— WS60I Ws600 ce aati WS5S7 WSS96 WS585 W539"
MILES FROM COAST Daas 'wss
34:5 %o
w
Wy
oe
=
uw
=
= 200
ae,
a
a
WwW
a
300
34:4 %o
400 2 : :
SOUNDING IN METRES __ 5497 = 3265 2307. ~=—s«1593
Fig. 18. Distribution of salinity. Section off Cape Carranza, May 18-20.
STATION NUMBERS WS60! wS600 S599 wssa 8 == WSS97 wssS96 ~=WSS95 WSp94
ft ' 1
MILES FROM COAST 75 co 25 ' WSS93
100
DEPTH IN METRES
in®)
io)
o
3004
400- . :
SOUNDING IN METRES__ 5497 = 3265 2307 S93
Fig. 19. Distribution of temperature (° C.). Section off Cape Carranza, May 18-20.
The position of these sections is shown in Figs. 3 and 7.
TEMPERATURE 139
NS6O
STATION NUMBERS_WS607 Na WS608 ws603 WS6IO W565 sets SAP
| te 50 1
a
MILES FROM CoAST_ ! l2s
100
wv
if
S
z 200
3=
i
a
WwW
a
300
345%
400 . --— . : 50
SOUNDING IN METRES = 3550 = _— 2500 1296 687
Fig. 20. Distribution of salinity. Section off Pichidanque Bay, May 28-30.
WS604 _ WSE02
STATION NUMBERS _ WS607 WS606 WS608 wWS603 WS6IO —WSENS | WSE03. |
MILES FROM COAST‘! I25 \G0 75 50 25 :
1 i '
100 4
w
2
ao
=
Ww
=
z 200
ae
=
a
a
Qa
300
a
400 . 3 > = : —
SOUNDING IN METRES_ — 3550 = : 2500 1296 687
Fig. 21. Distribution of temperature (° C). Section off Pichidanque Bay, May 28-30.
The position of these sections is shown in Figs. 3 and 6,
D XIII
140 DISCOVERY REPORTS
May 28, wind was either absent or blew gently from the south-west, and no immediate
connection is to be supposed between this wind and water at this depth. On the other
hand, the association between cool water at the surface and the easterly wind at Sts.
WS 604 and 605 is suggestive of a direct relation.
After completion of Sts. WS 606 and 607 in the open ocean, a strong southerly wind
arose which drifted the ship northwards as shown in Fig. 6. The possibility that the
upwelling noted in Fig. 21 may be an indirect effect of this wind is discussed on p. 210.
30-25°S: CALDERA
The inshore water at Caldera showed signs of active upwelling, and immediately to
the southward cold water was met at the surface as far out as 33 miles. Elsewhere, how-
ever, warm water was close to the coast and inshore winds were northerly. Irregularities
of surface temperature as found in this region (Fig. 17, Tables XX and Appendix IV)
are frequently met with where warm and cool water meet; but while convergence of the
warm water with the cool inshore, and a ragged boundary between the two, may be
consistent with a recent change of inshore wind to the north, the question whether
the cool water was upwelling at the same time has not been decided.
The changeable condition met with on the surface, also noted in reference to wind
and drift in Fig. 8, extends to the subsurface layers and is illustrated in the temperature
section off Caldera in which almost phenomenal irregularity is shown (Fig. 23). An eddy-
like movement beneath the surface at 10-15 miles offshore, Sts. WS 616 and 618 may
indicate a sinking of newly mixed water. Witte’s (1910) account of the theory under-
lying this phenomenon may be quoted :1
When on the boundary of an ocean current, warm water of high salinity is brought into contact
with colder water of less saline character, but having approximately the same specific gravity, then
the resulting mixture will, as may easily be proved by the Knudsen tables, be of greater density than
either of its component parts. It will consequently sink down, giving rise to the peculiar phe-
nomenon known as “‘cabbeling”’.
Comparison of the temperature, salinity and density of the upper 20 m. at Sts.
WS 614-620 shows that these conditions come near to fulfilment (Table II). Thus
if surface water from Sts. WS 617 and WS 615 were mixed in the ratio of 5: 8, the
mixture would have a salinity similar to water at St. WS 618 (34:36 °/,.) but with a
density of 25-94. This value would not be in equilibrium with surrounding water until
it had sunk to a depth of about 40 m.
Inshore upwelling at Caldera (Fig. 22) cannot be traced to greater depths than
100 m., but offshore, upwelling may be traced to a depth of 250-300 m. The inshore
water at these depths is seen to have a higher temperature than water in the open
ocean; later it will be shown to be a highly saline return current having a southerly
flow—1t is a coastal current: the offshore water is lighter, is sub-Antarctic in character,
and probably has northerly flow (Fig. 22).
No adequate idea of water movement can probably be obtained from a single line of
T ‘Translation from Sandstrém (1919).
TEMPERATURE I4I
stations in such a turbulent neighbourhood. Streams of water may have been rising or
falling across the plane of the section and may have been the cause of repeated fouling
of the wires used with hydrological instruments. Two of these wires are used simul-
taneously on one side of the ship, one forward and the other aft, for working the deep-
and shallow-water bottles, and they are well weighted with sinkers: the wires rarely
fouled one another, but on this line at St. WS 616, they were continually becoming
twisted round one another until eventually it was found impossible to have them both
working at the same time.
Table Il. Comparison of temperature, salinity and density off Caldera, Fune 5-6
Station
Depth z : ates OF) eee
toa WS 620 WS617. WS618 WS616 WS615 WS614
Memps .\C: co) 16°50 15°90 I5*10 14°88 14°20 13°45
10 16-21 15°90 14°22 13°90 14:21 13°45
20 16°18 15°65 13°80 13°35 13°50 13°40
Salinity °/,. o 34°45 34°44 34°36 34°34 34°31 34°31
10 34°44 34°44 34:28 34°32 34°34 34°36 |
20 34°44 34°44 34°35 34°36 34°37 34°35
ot fo) 25°21 25°35 25°46 25°49 25°62 25°77
10 25°27 25°35 25°59 25°69 25°64 25°81
20 25°28 25°40 25°73 25°83 25°81 25°81
25-18°S: ANTOFAGASTA AND ARICA
The hydrology of this stretch of the coast bears a resemblance to the preceding,
in that surface temperature was uniformly high except at Antofagasta where low tem-
peratures were conspicuous. The general uniformity of surface temperature may be
traced to warmth in the southern part of the region resulting from the northerly winds
already noted between the parallels of 26—30° S, and in the north to marked upwelling
resulting from strong inshore current. Upwelling at Antofagasta seemed in a more
active phase than at Caldera, since the upper layers of the highly saline return
current were found at the surface. In other respects temperature sections from both
localities agree in showing that the upwelling water was drawn mainly from the less
saline sub-Antarctic water; compare Figs. 22 and 23 with 24-27.
Conditions at Antofagasta were also very changeable. After the ship had worked her
outward line of eight stations (Sts. WS 622-629, Figs. 24 and 26), it was necessary to
repeat a second line of observations (Sts. WS 630-635) on the return shorewards, this
time a little farther to the north owing to the drift of the ship; for within the short
interval of 30 hours, the temperature, salinity and phosphate distribution had changed
considerably.
On the outward journey the surface temperature inshore was about 14° C. and did
not show the usual rise for some 10 miles when it suddenly jumped up 33° in 21 miles
5-2
142 DISCOVERY REPORTS
and reached 17°59 C., 2 gradient CONN egies STATION NUMBERS_WS6I2 WS6I9 W5620 WEE] NSE SEH
ableto the rise off Caldera (Fig. 29). There MILES From coast." 50 Sea le Peta
was little further rise, the temperature ; ie =e ee
touching 18-04° C. in the course of work
on St. WS 629 at 46 miles offshore. Wind
blew from the east and south with force
4 which increased to 5 from south-south- 100
west in the open sea. During this time
the ship’s track from Sts. WS 622 to 630
deviated 11 miles to the northward, and
in addition the drift had an appreciable
westerly component (Fig. 28).
The return journey commenced with
34-4 %o
2004 - 347%
DEPTH IN METRES
a moderation from force 5 to 2 in the
southerly wind which later changed di-
rection to the north; but before any change 300
in the direction of the wind was noticeable, ae
the water temperature at this distance from
shore had altered and the surface isotherms
had closed with the coast. Whereas on the Pa eure eo) Neal
outward run the temperature rose sharply SOUNDING IN METRES 586! 4664 — 3031-1768 1132
between 10 and 21 miles offshore and from Fig. 22. Distribution of salinity. Section off
. Caldera, June 4-6.
31 to 46 miles had undergone no change, aa
o) {i} ISWS6I3
on the return journey the temperature son wners_wece wssr9wsge0 WOR ER WE
50 re3}
fell from. 17-9° C. and followed an even ‘®FROWCHST—
curve, dropping at first slowly and then
rapidly until it reached 14-9° C. at 2 miles
from shore (Fig. 29). Thus the temperature
was generally warmer ; the isotherms of 17,
16 and 15° C. had all moved towards the 100 -
shore, while water of 14° C. had dis-
appeared. At the same time the ship was
carried in a north-easterly direction, as
8
may be inferred from the positions at the E ety
beginning and end of St. WS 630, during =
which the ship was drifting for 12 hours 8
(Fig. 9).
The question whether temperature
changes on this line can be correlated eae
with change of wind or with some cause
due to the new locality into which the
ship had drifted, may now be considered.
In the first place it is to be noted 4o0-l. eae Se ere ty
that positions of isotherms had been eee
Fig. 23. Distribution of temperature (° C.). Section
off Caldera, June 4-6.
The position of this section is shown in Figs. 3 and 5.
TEMPERATURE 143
WS630 W828 SSIS lweze
RS_WS623 WSE32 W
Sr gery = alist aaa STATION NUMBERS — S629 WS630 WSESI SBEWSES5
a MILES FROM COAST es ere
See Wiaeer Meal
i 348% 347% Willse
= ie
34.5% ,
00
100
345 %o
ny
a ra
0 =
aC z 200
BS
EF fe
) i
2 34-72%,
300 3004 + \y aes
200 ——————————— Sigler |
TRES— 7159 = = | 1s0l609 400 +. . ely
poCUD ING INMETRES 294 1038 SOUNDING IN METRES — 7159 - = =-—70
Fig. 24. Distribution of salinity. Section off Anto- Fig. 25. Distribution of salinity. Section off Anto-
fagasta on the outward journey, June 8-9. fagasta on the return journey, June g—10.
W567 W625 WSEZ3
WS632 WS634
PUA ONIN OE Ra ons aie wt bie STATION NUMBERS _WS629 w5630 WSN | SSIES.
MILES FROM COAST_ a MILES FROM COAST___ ! eS
100
DEPTH IN METRES
i)
i=}
o
DEPTH IN METRES
300
=e eae
a0 =” eee | ms
us =: 400 . c Meee
SOUNDING IN| METRES— 753 lg49 laos SOUNDING IN METRES 7159 - = —- =700
Fig. 26. Distribution of temperature (° C.). Section Fig. 27. Distribution of temperature (° C.). Section
off Antofagasta on the outward journey, June 8-9. off Antofagasta on the return journey, June g—ro.
The position of these lines is shown in Figs. 3 and 9.
144 DISCOVERY REPORTS
undergoing alteration before reversal of the wind: secondly, after the wind had changed
to a north-easterly direction and to force 2, the ship continued to drift in its face to
the north-eastward (from Sts. WS 630 to 632). If wind direction alone were to be
considered these facts would argue against the wind being a controlling factor; but
the strength of the wind is equally important, and the conditions here probably
illustrate its influence exceptionally well.
Fig. 28. Changes in wind and in the distribution of surface isotherms off Antofagasta in the period June 8-10,
1931. The sequence of events described in the text may be traced by following the track of the ship (thin
line in direction of thin arrows) from Punta Tetas. The position of stations on this line is shown by dots
(cf. Fig. 9). Isotherms are indicated by heavy lines, wind direction and force by broad arrows. The dotted
lines show the shift of the isotherms of 15, 16 and 17° C.; the isotherm of 14° C. had disappeared when the
site occupied by it on June 8 was revisited on June ro (see Table III, and compare with Figs. 24-27).
Comparison of Figs. 26 and 27 shows far more active upwelling and far more cold
water at the surface in section 26 of the outward journey than in 27 on the return. The
wind data show a similar contrast of strong southerly and easterly winds on the west-
ward journey and weak northerly winds during the return (Fig. 28). While the subse-
quent rise in surface temperature with change of wind might have been brought about
by mixture of the upwelled with offshore water, the evidence of the ship’s drift raises
another possibility. We may picture the lighter warm surface water driven away from
the coast as a result of these strong southerly and easterly winds acting in conjunction
UPWELLING AND SUBSIDENCE—ANTOFAGASTA 145
with the deflecting force of the earth’s rotation, and so drawing up to the surface a mass
of heavy cold water from below. It becomes a system charged with potential energy.!
We may imagine the ship taking observations on the outward journey at the height of
this process, and that her drift was in the path of the deflected waters. But as soon as
the wind force relaxes from force 5 to 3~—2, as it did after St. WS 629, the deflecting
force and so the pull of the warm offshore water is also relaxed, the cool inshore waters
subside, and eventually the former warm surface waters flow back, and we have the
conditions met on the return journey. In this way the north-easterly drift of the ship
from Sts. WS 630-632 on her return journey, might indicate the influence of the
returning waters. The displacement of the surface isotherms with the changing wind
conditions is illustrated in Table II. The first section (Fig. 26) may illustrate upwelling
and the second (Fig. 27) subsidence.” The question is discussed further on pp. 206,
208 and 213.
Table III. Change in position of surface isotherms off Antofagasta
Position of isotherms :
(miles from the coast) Displacement of
a eee isotherms
June 8, 9 June 9, 10 (ailes)
nu” (Ce 8 = ==
mG (Ce 12 2 10
idays (Ge 28 ie) 18
mes 30 15 15
stesh7 (Ce 46 46 fo)
Wind: Direction S4°E NreE
Force, m.p.h. 12°7 6-1
With a change in the wind from south to north, the isotherms of 15, 16 and 17° C. shifted towards
the shore.
In the Bight of Arica it was interesting that a strong inshore current and upwelling
should occur in the absence of any wind. The weather was calm and the high tempera-
ture of 19:1° C. was found unexpectedly close to the coast, a well-marked thermocline
existing close to the surface. The absence of any sign of an earlier disturbance suggests
that upwelling was probably at its height. The possibility that these high tempera-
tures were related to a wedge of warm highly saline water off Peru is suggested in Figs.
16 and 17, and that they might have been due to a counter-current is discussed on
Pp. 192-3.
1 Sandstr6m uses the term ‘‘ Archimedean forces”.
2 The possible influence of the land contour upon the extent of upwelling and consequently upon the
amount of cold water to be found inshore, and the possibility that the water mass off Baia Herradura is of
different origin to that off Punta Tetas should not be lost sight of ; they are discussed on p. 208.
146 ; DISCOVERY REPORTS
19°C
ARICA — JUNE 19-20
ANTOFAGASTA — JUNE 9-10
ANTOFAGASTA — JUNE 8-3
CALDERA — JUNE 4-6
PICHIDANQUE BAY
MAY 28-30
1S
14
14°C
CAPE CARRANZA __ MAY I8-20
I3
l2
® OBSERVATION AT STATION
* OBSERVATION BETWEEN STATIONS
100 50
MILES FROM COAST
Fig. 29. Curves illustrating the surface temperature across the current, along lines placed
normal to the Chilean coast.
Note to Fig. 30. The temperature values plotted in the curve Guaiiape Islands, July 10-11 should be
read as one degree lower than those shown on the scale: the curve includes data collected off Salaverry at
Sts. WS 675 and 676.
SANTA ELENA JULY 3I—AUG!
CAPO BLANCO __ JULY 24-26
PUNTA AGUJA —_ JULY 21-23
LOBOS Is. JULY I7-20
GUANAPE Is __ JULY IO-II
GUANAPE Is _ JULY 9-10
CALLAO _ AUGUST 20-2!
CALLAO _ JULY I-3
SAN JUAN __ JUNE 21-23
© OBSERVATION AT STATION oa
¢ OBSERVATION BETWEEN STATIONS
a T T
150 100 50
MILES FROM COAST
Fig. 30. Curves illustrating the surface temperature across the current, along lines placed normal to the
Peru and Ecuador coasts.
148 ; DISCOVERY REPORTS
18-12°S: SAN JUAN AND CALLAO
The meteorological and hydrological conditions off San Juan and Callao present an
interesting contrast with one another and with those off Arica (compare Figs. 4 and 16
and also 31-33). At Arica in calm wind-free conditions, surface isotherms were bunched
close to the coast, yet upwelling and northerly current were strong inshore. Off San
Juan a strong south-east wind blew and upwelling was such that the surface isotherms
spread out from the coast. Off Callao the wind lay towards the shore, with a slackening
of upwelling and with the surface isotherms again bunched close to the shore.!
Off San Juan the volume of cool water was greater than at any region hitherto
examined. Upwelling phenomena were evidently at their height, and the temperature
rose from 13°79 to 19:25° C. at g5 miles offshore. Beyond this the ship crossed a patch
of water, warmer than the sea on either side, and which appeared to differ from the
surrounding water in its movement (see P. station numeers_wss38 WS633 — WS643 wade [S640
i ' | '
129). It was some 50 miles wide and had “°*"O8T— 0 Gr
a maximum temperature of about 19-48° C. :
A warm wedge of very similar water was ees
met later off Callao where it was also about Pee eee
the same width but closer to the coast; .
here its direction of movement was not 100
noted. Northwards of Callao the wedge ss
was traced to the Guanape Islands and
possibly beyond, and later in the season it 2
was again identified off Callao (see p. 171). 2 50 ee
Its appearance in section is seen in Figs. = bei eet
22,33) and) 52.
The absence of current at Callao, the on-
shore wind and the closing of surface iso- See
therms with the coast, indicate that the eal as
temperature section illustrated in Fig. 32
may be a record of subsidence and not of Pe
an upwelling of cool water. This conclusion
receives further support from observations 400 2 —~ ; :
of a seasonal character given on pp. 169- cet ee ae a o
Jie7/tieyy) Okey 153
These features are illustrated in the shown in Figs. 3 and 11; the corresponding salinity
curves of surface temperature along the section, in Fig. 43.
path of the current (Fig. 34). Curves illus-
Fig. 31. Distribution of temperature (°C.). Section
off Arica, June 19-20. The position of this section is
? It should be understood that in this account the observations are presented in chronological order and
that the hydrological conditions are therefore traced from south to north. To avoid inconsistency in treating
the subject as a whole, it is necessary, also, to trace counter-currents against their direction of flow. The
reader is asked to bear this in mind, particularly in the description of the warm wedge; conclusions on its
nature will be drawn after the evidence of salinity and of other data has been considered.
TEMPERATURE 149
WwSé64
STATION NUMBERS _WSE68 WS669 WS670 WSE7I WS667 WSEG6 —WSEE5_|WSE63
MILES FROM COAST__ 100 "75 : 50 } 25 : ,
| i}
200
DEPTH IN METRES
300
ae
400 : :
SOUNDING IN METRES 4285 3840 = 934 474
Fig. 32. Distribution of temperature (° C.). Section off Callao, July 1-3. The position of
this section is shown in Figs. 2 and Io.
WSH48
STATION NUMBERS_ WS65S3 WS654 WS652 WSE5S WS656 WSE57 WS546 WSESI WS650 WSB49 | WS647
|
MILES FROMCOAST__—-'1S0 Nes 100 75 50 es
|
100
w
2
ce
a
w
= 200
z
x
=
a
we
Qa
300
is a
400 F ; 2 ° . :
SOUNDING IN METRES__ — - 3840 3315 ~ - 3147 1264
Fig. 33. Distribution of temperature (° C.). Section off San Juan, June 22-24. The position of this section
is shown in Figs. 2 and rt.
Salinity sections corresponding to the Figures on this page are illustrated on p. 165
se
Bk 5 oes
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6 << Fs, Le a = = Be ae =
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a 2 ay = = = Bl Zaza 2
S = S < < rr) o S26 &
ae eee tL i
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Wel ] 200-500
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= 100-200 MILE ZONE__-Z \ ,
66 8 ear a 50-{OOMILE_ o,
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Te ili? a =
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IS < 2MILE ZONE a Beh ;
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40° 30° 20° 10 OS. LAT.
Fig. 34. Curves illustrating the mean surface temperature along the path of the current. Each curve
represents the temperature of a zone at a given distance from the shore, the data within it being averaged
separately for each degree of latitude (Appendix VI). The curves are broken where data are wanting. Regions
influenced by an inflow of warm oceanic water (vide warm wedge in text) are indicated by a heavy line.
TEMPERATURE 151
trating the mean surface temperature of the inshore zones, at 2—5 miles and 5~10 miles,
agree in showing a pronounced fall of temperature at Antofagasta and a recovery
which reaches its peak at Arica; but within 2 miles of the coast water remains cool,
and this is interesting since there is no wind. After Arica, where the coast alters
direction and the winds had increased very considerably, the water within 5, 10 and
even 50 miles of the shore was found to be cooler than it had been since the latitude of
Coquimbo. From San Juan to Callao another rise in temperature was taking place, and
this is where wind was blowing across the usual direction and towards the shore
(Fig. 4); the isotherms ran closer to the coast, the cooler water having disappeared
(Fig. 16).
In the offshore zones, the curves for 10-20 miles, 20-50 miles, 50-100 miles and
100-200 miles, come under the influence of the warm-water wedge which is picked out
in Fig. 34 by heavy lines. Off Arica its influence is shown in the zones 10-20 miles and
20-50 miles, but lack of observations farther out makes its seaward boundary doubtful.
Off San Juan its influence is shown by the two outermost curves only. Off Callao,
where the warm-water wedge is close in, the curves for the 1o-20-mile and the
20-50-mile zones are affected and a big rise of temperature is shown, whereas at greater
distances from the coast the water is cooler. Northwards of Callao the wedge comes from
the open sea and a sharp drop occurs in the 10—-20-mile and in the 20-50-mile curves
and even in the 50~100-mile curve which continues to drop as it enters more northerly
latitudes. The N-shaped appearance of the warm-water wedge in this figure is of course
given by the arbitrary arrangement of the curves and by the latitude scale having been
compressed.
12°-5°S: GUANAPE ISLANDS, LOBOS ISLANDS AND PUNTA AGUJA
In the month of July 8 to August 7, the ship made four traverses of this region; once
to Salaverry and back to Callao, and once to the Ecuador coast and back: she was thus
able to make a more detailed examination of the current in this region than southwards
of Callao (Fig. 2).
Northwards of Callao the spreading out tendency of surface isotherms is again in full
play and winds are consistently south east. It is most noticeable in the warm-water
wedge! which first gains in width and then slants away from the coast to a distance of
over a hundred miles. In consequence, the lines of stations off the Guanape Islands,
Lobos Islands and Punta Aguja from 107 to 204 miles in length, all fail to span it
(Fig. 30). The shift seawards of the warm-water wedge has already been noted above
in the curves of mean temperature (Fig. 34). At the same time the wedge loses de-
finition. As it leaves the coast, the inshore waters become more and more homo-
geneous and the wedge less easily discerned. Whereas off Callao and the Guanape
Islands its inshore margin was distinguished by a sudden change of temperature,
farther to the north the surface temperature undergoes no sudden change (cf. the
gradual rise off the Lobos Islands and Punta Aguja, Fig. 30). This increasing homo-
1 See footnote on p. 148.
152 ; DISCOVERY REPORTS
geneity is shown in both temperature and salinity in the upper 200 m. at these four
localities (compare Figs. 32 and 36-38 with Figs. 44 and 46-48), and is probably
attributable to progressive vertical mixture resulting from increased current off northern
Peru. Thus the Peru Coastal Current gains immensely in breadth towards its northern
end.
As the latitude of this section of the coast is lower than those previously examined,
there is a natural rise in the general level of the surface temperature and salinity.
A surface temperature of 16-00° C., that off Salaverry, is the lowest inshore temperature
recorded in this region: in the wedge of warm water the temperature reaches 20:60° C.
Fig. 35. Changes in wind and in the distribution of surface isotherms off the Guafape Islands in the period
July 9-11, 1931. Symbols as in Fig. 28. Station positions may be identified by collation with Fig. 13. The
dotted lines show the shift of the isotherms of 18, 19 and 20° C. (see Table IV).
The region of the Guafiape Islands and Salaverry was examined in two states of the
wind within a very short time (Fig. 35). In the evening of July 9, St. WS 674 was worked
at 56 miles from land in winds of S 35° E with force 1-3 to 5-8 m.p.h. From this position
the ship ran to Salaverry during the night, taking a record of surface temperature as she
went (‘Table IV and Fig. 30). On the following night the ship worked a line of stations
outwards from the Guafiape Islands back towards the position of St. WS 674. In the
meantime the wind direction had changed from south-south-east to south-south-west
with force 1-2 m.p.h., and all isotherms at 20 miles to sea and upwards were now found
closer inshore. The greatest displacement was over the middle of the shelf some 30 miles
TEMPERATURE 153
from shore: here the 18° C. isotherm was 12 miles closer to land on the return outward
than on the shoreward run: and at 50 miles the 20° C. isotherm had shifted shorewards
about 9 miles. There seems to be no reason for thinking that this apparent change in
the position of surface isotherms is due to an error in the ship’s position and the
synchronous change in wind suggests as more likely that the latter is related to the
former as cause and effect (cf. conditions at Antofagasta). The question whether the
section in Fig. 38 represents a process of subsidence after upwelling rather than a
state of incipient active upwelling, is examined on pp. 208-9 and 213.
Since the ship was prevented from taking observations at less than 7 miles from the shore by the
position of the Guafiape Islands, three additional stations were worked in Salaverry Roads for
the purpose of examining inshore conditions. Here a temperature of 16° C. was recorded at 5 miles
from the shore (Appendix IV), and since it was recorded very soon after the change of wind from
east to south-west, it may be conjectured that this is a legacy of the former strong wind rather
than a consequence of the weaker.
Table IV. Change in position of surface isotherms off the Guanape Islands
Position of isotherms :
miles from the coast Displacement of
isotherms
a aeaes miles
July 9, 10 July to, 11
20m C. 55 46 9
19° C. 46 34 II
18° C, 42 29 12
7a C: 14°5 8-5 6
16> GC. — 5 =
Wind: Direction E and ESE SW-SSW
Force, m.p.h. 2-10 2-5
With a change of wind from east to west the isotherms of 17, 18, 19 and 20° C. shifted towards the
shore.
The lines off the Lobos Islands and off Punta Aguja, situated comparatively close to
one another, are similar in plan, illustrating the progressive widening of the Peru Coastal
Current and the progressive homogeneity of the upper layers.
The better part of a week elapsed between completion of the Guanape Islands and
commencement of the Lobos Islands line, the work being interrupted by a visit to
Callao. The dangers of heavy drift around the rocky isles Lobos de Tierra and Lobos de
Afuera precluded the usual course of letting the ship drift before wind and current:
also an endeavour was made to examine the effects of these rocks upon the hydrological
conditions. Accordingly courses were shaped, first to take observations off the exposed
(south and south-east) aspects of the Lobos de Afuera, and then to place stations along
a line midway between the latter and the Lobos de Tierra.
Compared with other lines, upwelling off the Lobos Islands seems in abeyance and
the surface layer is comparatively warm, a value of 17-38° C. being the warmest inshore
temperature met. This layer is also seen in Fig. 47 to be more saline than the sur-
rounding water. Such a distribution of warm saline water leading to a slackening of
DISCOVERY REPORTS
154
‘gh “Sty ur ‘uonsas Ayrur[es Surpuodsaiioo oy} {zI pur
Z ‘SSI UI UMOYS SI UOT}Oes sIy} Jo uoTpsod oy, “fc—-1z Aqn{ ‘efnsy eyuNg Yo uonsag *(‘d,) cMjesiodusay Jo uornqmysiq “gf “31
ego! 20l€ 2blb = 920b ~ — —S3¥13W Ni INIGNNOS
3 <a 5 : ia j ; : OOF
Bi ee ia ;
ES)
+ OOE
+ 002
S3SYLIW NI Hid3G
-- O00}
om ; 2
; eS ee
Se OS
Sihaal 1 | . SL ool Sel os | ofl 002 |
BESSM! OOLSM 10LSM e02SM €OLSM M / a
LESSMEEISM vOLs SOLSM 30ZSM ZOLSM SY3ISWNN NOILVIS
~ LSvOD WO¥s S3TIN
TEMPERATURE 155
STATION NUMBERS_WS687 WS6B8 ESS WS696 WS695 WS694 WS693 WS692
I
MILES FROM COAST___—25 100 7S 50 25
=o . . . . . —
== ea ee eee
100 -
200-4 -
DEPTH IN METRES
400 . . ° 5
SOUNDING IN METRES 4492 = 2093 (S01 367 (216
Fig. 37. Distribution of temperature (° C.). Section off the Lobos Islands, July 17-20. The position of this
section is shown in Figs. 2 and 12.
wS673
STATION NUMBERS —WS686 WSE74 WSeB2 WSEBI WS6BO | WSE78
MILES FROM COAST _— 100 75 50 1 1 25 1
a — cle :
SS ee
———————
o SS
ww
a
5 Z .
Ww —$<
= °
zZ 100 ——— ae
= SS 142
a
wi
a
200
SOUNDING IN METRES _4206
Fig. 38. Distribution of temperature (° C.). Section off the Guanape Islands, July 10-11. The
position of this section is shown in Figs. 2 and 13.
Salinity sections corresponding to the Figures on this page, are illustrated on p. 167.
D XIII 7
156 DISCOVERY REPORTS
upwelling would be brought into being either by a counter-current or an eddy, the
existence of which is rendered likely by the evidence of set and drift which was erratic
in this neighbourhood, a current of 24 miles a day setting directly towards the shore
(north-east by north) between Sts. WS 689 and 690. The influence of these conditions
on the fauna and flora are discussed on p. 220, the possible influence of the rocks
on upwelling on pp. 205 and 207.
Although pronounced upwelling brought cold water to the surface within 15 miles of
Punta Aguja, yet over the next 189 miles the temperature rose no more than 2-2° C,
Thus immense breadth is a conspicuous feature of the northern part of the Peru Coastal
Current. The warm-water wedge seems to be recognizable though relatively less warm ;
its western margin (the isotherm of 20° C.) ragged, irregular, and ill-defined off Punta
Aguja leaves the area investigated. The eastern, shoreward margin of the wedge,
swerving outwards from the shore, is found at a distance of 50 miles off the Guanape
Islands, 140 miles off the Lobos Islands and 180 miles off Punta Aguja (Fig. 16).
5-2°S: CAPO BLANCO AND SANTA ELENA
Here the current leaves the coast on its entry into the tract leading to the westerly
flowing South Equatorial Current. We are concerned with its point of convergence
with the warm waters off Ecuador. Although the hydrology of the complex region
outside the Peru Current is beyond this enquiry, the following notes derived from Schott’s
valuable paper (1931) will assist in the interpretation of conditions near the coast.
Cool water of moderately high salinity (>35 °/,,) is brought into the region from the
south by a chain of processes constituting the Peru Coastal Current, and it is drawn off
to the westward in the wake of the South Equatorial Current. North of this the
Equatorial Counter-current flows eastwards in the opposite direction, and brings warm
water of low salinity (< 33 °/,,) into the region from the west. The characteristics of
these two currents are very different, and the coasts adjoining them differ from one
another correspondingly. The warm counter-current, whose salinity has been lowered
by tropical showers, flows against Ecuador, and the country has luxuriant forests
drenched by rains. The Peru Current has acquired its higher salinity through the
drying action of the south-east trades and the Peruvian coast along which they blow
is a desert region. Similarly the Cocos Islands in the path of the counter-current have
tropical scenery, whereas the Galapagos Islands in the South Equatorial Current has a
much more scanty vegetation.! But it is not clear from Schott’s account whether the
relation of current to climate in the one is the same as that in the other. In the first
1 The appearance of the Galapagos vegetation varies. Darwin (1845) remarks that ‘‘ Nothing could be
less inviting than the first appearance. A broken field of black basaltic lava thrown into the most rugged
waves, and crossed by great fissures, is everywhere covered by a stunted sunburnt brushwood which shows
little signs of life.”’ Agassiz (1891), on the other hand, writes: “ Arriving as we did at the Galapagos at the
beginning of a remarkably early rainy season, I could not help contrasting the green appearance of the slopes
of the islands, covered as they were by a comparatively thick growth of bushes, shrubs, and trees, with the
description given of them by Darwin who represents them in the height of the dry season as the supreme
expression of desolation and barrenness.”’ The climate of the islands must depend upon the position of the
convergence between the counter-current and the South Equatorial Current.
STATION NUMBERS _
MILES FROM COAST_
ws7!3 WS718 WS717
WS7!6 WS7IS
! |
POSE 2 2a® wa
~ = = Ss
20
i ee
a _ SaaS SS SSE
SS Se
100 : yA
rs Sora
0
©
=
=
= 2004 ;
r 1~¢@—$——
i
a
&
a
SS
Ss
122
300 4 ee ~
ae
10
400 : . :
SOUNDING IN METRES— 3108 =a 1649
Fig. 39. Distribution of temperature (° C.).
off Santa Elena, July 31—August 1.
STATION NUMBERS _WS 722
MILES FROM COAST_
Section
ws703
STATION NUMBERS — WS713 ws7l2 WS f | ws7!0
' '
MILES FROM COAST—
os
25
100 4
no
us
oe
BE
=
z 200-4
z /
a /
a /
a BOnmG
/
fo
ve
300-4
400 os —
SOUNDING IN METRES — = 1885
Fig. 40. Distribution of phosphate (per m.’).
Section off Capo Blanco, July 24-26.
100
DEPTH IN METRES
300 =
WS709
ws708 WS7l4 WS73 WS7I2 —WSTII Wsro |
100 75 : Ue 25 nt
l ! | !
™ == ————
3 oy! B92 age 2 22S
400 :
SOUNDING IN METRES_ —
1885
Fig. 41. Distribution of temperature (° C.). Section off Capo Blanco, July 24-26.
The positions of the sections on this page are shown in Figs. 2
<A)
70 and 71; the
corresponding salinity sections, on pp. 169 and 168.
158 DISCOVERY REPORTS
the counter-current is accessory to the cause of humid winds, tropical showers and its
own low salinity, while in the second, drying winds are the cause both of the coastal
deserts and the high salinity of the Peru Current (see p. 229).
Along the line of contact where the two currents converge, water movement gives rise
to extensive mixture. The triangular area of the Guayaquil-Galapagos-Panama region
is one of irregular currents and complex eddies. Water movements on a much vaster
scale result from variation in one or other of the controlling forces that lie outside this
province: thus failure of the trade wind or preponderance of the northerly will
cause a phenomenon like E/ Nino. The boundary between hot and cold water possibly
affords a delicate indication of the balance between factors remote from the area itself.
At the time of our visit the convergence of the cool Peru water and the warm water
from Ecuador, occurred off Capo Blanco: it followed an irregular $-shaped line within
50 miles of the coast, and here the isotherms lay close together. The convergence line
then pursued a north-west direction and was less defined (Figs. 16, 70 and 71).
The sections across this region illustrate clearly the relation to one another of the
waters of different temperature (Figs. 36 and 39-41): that off Punta Aguja is typical of
sections south of this line in which cooler water is brought to the surface by upwelling.
The next section cuts across a tongue of hot water off Capo Blanco. The hot water was
scarcely 20 m. deep, lay over the cooler Peru Current and extended about 25 miles
from the coast; its temperature ranged from 19 to 22°C. The Peru Current beneath
sustained a local rise in temperature, but in other respects the section resembles
those already examined. ‘Thus the 17° C. isotherm occurred at the surface although as
far out as 35 miles offshore beyond the hot-water tongue. A small patch of water of
19° C. at 55-65 miles from shore, like the hot-water tongue, was a sign that the northern
boundary of the Peru Current was near.
Off Santa Elena, transformation of conditions was more complete. Hot water of
24°43° C. occupied the surface close inshore, and proceeding out to sea the temperature
fell instead of rising as it is wont to do off Chile and Peru (Figs. 29 and 30). At 50 miles
offshore the temperature was 23° C., a drop of 1-4° C., but the hot water probably
extends westwards a considerable distance before it comes into direct contact with the
cool Peru Current. Although this section is the converse of those we have been
describing, upwelling seemed not altogether absent; it seemed to be held in check by a
thermocline at 20-56 m. In this layer the temperature dropped from 24 to 16° C., and
it is possible that such a layer of hot water might lie on the surface like a blanket and
effectually check vertical mixing even in conditions otherwise conducive to upwelling
(cf. conditions at Capo Blanco and conditions in the Gulf of Panama, p. 206).
The surface temperature of the area just considered is illustrated in Fig. 34 in which the mean
changes in zones at varying distances from the shore can be traced from south to north. We have seen
in the preceding pages that wherever the warm-water wedge encroaches upon these zones the mean
temperature undergoes a sharp rise. ‘This rise is shown in Fig. 34 by thickened lines. The curves also
show the sudden increase in surface temperature as they leave the Peru Current and enter upon equa-
torial water in the Gulf of Guayaquil. They show too that the contrast is greatest close inshore when
they leave the upwelling region of Peru and enter the high temperatures off the Ecuador coast,
SALINITY 159
illustrating the principle already noted that inshore temperatures in the Peru Current are cooler
than those offshore, while north of the Peru Current inshore temperatures are warmer than
those offshore. The curve at 10-20 miles offshore shows by its progressive warming from 8 to 4° S
that the influence of coastal upwelling is less and that the influence of equatorial water is not much
felt south of Capo Blanco. The water in the zone 50~100 miles offshore does not show great warmth
off Ecuador; its salinity between 2 and 3° S suggests a mixture of the Peru and tropical waters. The
curve for greater distances (100-200 miles) has no appreciable temperature rise and indicates that
the water is of more purely Peruvian origin.
5 AlENG t ¥.
In the preceding section, the cool water at the surface inshore has been shown to be
derived from lower layers by upwelling, and in certain localities the distribution of
surface isotherms suggest horizontal movement also. But the origin of the water masses
participating in this circulation is less easily seen in distribution of temperature because
of the regularity of thermal stratification in the deeper water. At the surface, on the
other hand, salinity is a less straightforward guide than temperature because it is liable
to be altered by precipitation or evaporation. Thus in the south of the region the surface
water is diluted by rains of the temperate zone and offshore is less saline than water
at a depth of 160-200 m., whereas further north, as a result of the drying action of the
south-east trades, the surface offshore is more saline than the lower layers. In conse-
quence of this reversal of conditions and of upwelling near the coast, the Peru Coastal
Current south of the subtropical convergence is more saline, and north of the conver-
gence less saline than the surface of the ocean immediately adjacent.
Surface salinity in the southern part of the region is moderately low and is probably
sub-Antarctic water. At the subtropical convergence in lat. 24-26° S (Fig. 42) it sinks
beneath more saline but warmer subtropical water and continues northward beneath
it as a subsurface current. The subtropical water at the surface has a depth of about
40 m. and continues northwards at the surface until it meets with the still warmer
less saline Equatorial Counter-current. The convergence of these two water masses
is recognized as the northern boundary of the Peru Current, but the section in Fig. 42
indicates that the latter extends some way northwards beneath the counter-current.
Beneath these water masses is situated the Antarctic intermediate water whose low
salinity is derived mainly from molten ice.
The origin of water masses in the South Atlantic Ocean corresponding to these four
has already been described (Deacon, 1933), but their behaviour in the eastern South
Pacific is modified by the peculiar conditions obtaining on the west coast.
The section illustrated in Fig. 42, which is approximately meridianal, does not cut
the subtropical convergence sharply, but at the surface the isohalines of 34°40-34-90 °/.,.
are seen to be spread out between the parallels of 21 and 28° S. This shows that the
convergence is not crossed at right angles, but that it curves northward near the coast in
accordance with the general circulation. The inference receives ample confirmation
from Sverdrup’s results (1931). In his fig. 4 illustrating Sts. 50-60 in a north-west to
160 : DISCOVERY REPORTS
south-east direction the subtropical convergence is cut sharply; the isohalines of
34°40-34:90 °/,, being bunched between Sts. 55~57 in the positions given in Table V.
In his fig. 6 illustrating Sts. 60-70 which lie south-west to north-east, the section is in-
clined to run along the convergence; the latter is in consequence not well defined, but
the isohalines of 34:40-34-90 °/,, are spread out between Sts. 62 and 67, and the iso-
STN NOS __ WS60I WS607 wssi2 ws6e93 WS638 WS653 WS668 WS 686 Wael WS707 ws7!9
LATITUDE 135° | 30° ascii aoe | 15° U fo lc l
200
DEPTH IN METRES
300
<
< z < < < 2 Q 2 gy < Ss
<
y ao in E ow Fare) s9 wn an 39 iw
min) uw o wa Sw aS aw Qu oY JW
Pare) Su eS oY <= 52 = $2 ai <= wa
Baty oa == <4 w= 25 oS Ae SIS <= <=
<a 25 Ow a= Lo Ha iL Sn 4 Et Eg
OS Se ras 22 Sin rate) of 48 Zo zi
a iz =
ao gs 2 Z¥ ro) i a ie
Pa a TE = ra ra
= Ss) )
i te %
[s) o
Fig. 42. Section illustrating the distribution of salinity in the upper 400 metres along the path of the current. The section
runs roughly parallel to the coast and is situated at a mean distance of about 100 miles from it. The dotted line indicates
the value of the surface salinity at the inshore station corresponding to each of the stations plotted; and the broken line
indicates the maximum depth apparently affected by upwelling at each of these localities.
halines of 34-60 and 34-70 °/.., cross the section in three places. The positions occupied
by the convergence in this section together with our own results are also given in the
table, from which the convergence is seen to run east and west in the open ocean and to
curve northwards on approaching the coast. The disposition of surface isohalines given
by Schott shows a similar tendency. In the eastern South Atlantic, on the other hand,
the subtropical convergence pursues an easterly course, and in 10° E is placed in lat.
37° 30° S (Deacon, 1933, p. 211).
In consequence of this, the Peru Coastal Current crosses a convergence: and two
SANG Iay: 161
distinct water masses, the one sub-Antarctic, the other subtropical, contribute to its
formation.
Table V. Approximate position of the subtropical convergence in
the eastern South Pacific
Latitude Longitude
ow
as)
1928-29. ‘Carnegie’ Sts. 55-57 33 109
1928-29. ‘Carnegie’ Sts. 62-67 | = | 2
1931. Sts. WS 612-629 | 24-26 70-71
In the lower latitudes of the South Atlantic, Deacon recognizes a surface layer of high
salinity (> 36-00 °/,.) which he distinguishes as tropical water. A similar layer in the
eastern South Pacific occupies an extensive area near the centre of anticyclonic circula-
tion and was entered by the ‘Carnegie’ at about 1300-1400 miles from the South
American coast. No water of such salinity was met within the Peru Coastal Current,
but the salinity of the warm-water wedge was higher than that of water on either side.
In this connection a closer study of its salinity may be made; the depth at which the
maximum salinity values were found on the five lines from the Lobos Islands to Arica
being given in Table VI.
Table VI
St. WS... 687 686 | 671 igh | 67
te S 7° 42! g° 25" | 12°10 | 16°36’ | 19°48’
Salinity °/,. 35°27 35°47 35°59 | 35°34 | 35°05
Depth m. ° oO | 20 |
50 | 30
Salinity attains its highest value off Callao in about 12° S, declining towards north
and south. In the northern part of the region, the wedge appears to the westward of
our stations, and the salinity at St. WS 687 and to some extent St. WS 686 have been
lowered by admixture with upwelled water. At the Guanape Islands (9°5), Callao (12°S)
and San Juan (16° S), where the wedge was most developed, the maximum values show
a progressive sinking in depth with increase of latitude. Identification of the wedge
at Arica is not proven, but the maximum salinity values are well below the surface.
According to these and temperature data, the origin of the wedge lies at the surface
to the west of the area investigated: it may be a counter-current in the subtropical
water, but it may perhaps be regarded as of tropical origin.
Two other peculiarities of these water-masses are noteworthy. ‘The meridianal section
in Fig. 42 shows that the sub-Antarctic water, after travelling at the surface as far as the
subtropical convergence, sinks and then continues northward as a subsurface current
for some 10° of latitude; whereas in the South Atlantic, after sinking at the convergence,
the sub-Antarctic water returns southward almost immediately, in company with
162 DISCOVERY REPORTS
a southerly return current of subtropical water at 80-200 m. (Deacon, 1933, pp. 207-10).
Fig. 42 also shows a return current flowing southwards between the sub-Antarctic
water and the Antarctic intermediate water. The origin of this return current is not
very clear but seems to lie partly in sub-Antarctic water, partly in subtropical water,
between 10-20° S. It does not seem to be homologous with the Atlantic return current,
for it flows at a depth of 150-350 m. and will be shown in cross-section to be a coastal
current; it is not in evidence in the oceanic sections run by the ‘Carnegie’.
Thus, on the eastern fringe of the South Pacific, four principal water-masses enter
into the circulation of the troposphere. At the surface, northerly flow is characteristic of
the sub-Antarctic and the subtropical layers; and in the deep water, of the Antarctic
intermediate layer. Southerly flow at the surface is found in the Equatorial Counter-
current, and below the surface in a return current of subtropical water which penetrates
between the surface layers above and the Antarctic intermediate water below.
Of these water-masses the sub-Antarctic and the subtropical water are the most im-
portant to the Coastal Current, because it is from these layers that the upwelling
water is drawn. In lat. 32° S the sub-Antarctic water extends from the surface to a
depth of about 150 m., and in this latitude the isohaline of 34-50 °/,, might be regarded
as the boundary between it and the return current beneath. The isohaline of 34-40 °/,,
distinguishes this in turn from the yet deeper Antarctic intermediate water. In lat. 2° S
water of the Equatorial Counter-current having a salinity of less than 35-00 °/,, over-
lies the subtropical water which extends from about 40 to 600-700 m., and here the
isohaline of 34:60 °/.., may be taken to represent its lower boundary.
CAPE CARRANZA
The salinity section off Cape Carranza illustrates upwelling in temperate latitudes,
the saline return current rising up into less saline sub-Antarctic water at the surface
(Fig. 18). The highly saline return current flowing southwards is depicted by the
isohalines of 34:50 °/,,, and it seems more than probable that this current is confined to
the coastal region. One observation only, at 400 m. at 83 miles from land, represents
Antarctic Intermediate water.
PICHIDANQUE BAY
Off Pichidanque Bay the highly saline layer is also depicted by the isohalines of
34°50 /,,, and here too it is drawn towards the surface by upwelling, but less so than
at Cape Carranza, with the result that in sectional view (Fig. 20) the layer is seen to be
more band-like. In it, the highest salinities were inshore: and in Fig. 21 the isotherms
give some indication that this water was warmer than at corresponding depths in the
open ocean. Although surface salinity inshore is still higher than offshore, the increase
in oceanic values is a sign of the reversed conditions farther to the north. Pichidanque
Bay is south of the convergence. The Antarctic intermediate water has now sunk lower
than 400 m. and is not shown in this section. Upwelling occurs from 118 m., but layers
as deep as 212 m. seem to be affected.
SALINITY 163
CALDERA
The sub-Antarctic water and the highly saline return current are easily recognized in
Fig. 22. The observations off Caldera were only just south of the subtropical con-
vergence, and the latter’s influence is reflected in the surface salinity offshore which now
has a value of almost 34°50 °/,,. It is therefore higher offshore than inshore; a con-
dition characteristic of the greater part of the Peru Coastal Current. As a result of up-
welling the saline return current is drawn to within 40 m. of the surface ; but if upwelling
had been more active, the return current might have been drawn to the surface and the
inshore waters would then have had the higher salinity.
ANTOFAGASTA
The rise of the highly saline return current to the surface suggests that Fig. 24
illustrates upwelling of unusual strength, yet the salinity offshore (St. WS 629) con-
tinues to be the higher; this is because the subtropical convergence was crossed in
approximately lat. 24-26° S, and the outermost of the stations on this line lay on its
northern edge. The sub-Antarctic water, formerly at the surface, is now below the
subtropical water but apparently still flowing towards the north; below it the return
current flows south. Figs. 23, 26 and 27 show that the temperature of the return current
off Antofagasta and Caldera is distinctly higher than water of the open ocean.
If the inferences drawn on p. 142-5 are correct, the two sections illustrating salinity
off Antofagasta indicate first such upwelling that the highly saline return current has
been drawn to the surface inshore, and second that it has subsided beneath. In reaching
the surface, the return current has mixed with the sub-Antarctic water, with the result
that their salinities are modified; nevertheless the layers are clearly distinguishable.
Within the return current, salinity is in its highest concentration close to the coast, and
this distribution accords closely with the distribution of the layer off Cape Carranza
where upwelling had also been vigorous, and supports the suggestion that the layer is
restricted to the coastal region (cf. conditions off San Juan, p. 164). This is discussed
further on p. 200.
ARICA
At Arica the return current did not reach the surface, but the arrangement of
water layers is seen (Fig. 43) to resemble that of other sections. ‘The sub-Antarctic
water now having values of >34:50°/,.. is at the surface inshore, while subtropical
surface water now reaches values of >35:00 °/,..
SAN JUAN
The concentration of surface salinity at San Juan is such that the sub-Antarctic water
is becoming obliterated but is recognizable at 60-120 m. (Fig. 45). For 60 miles
the inshore surface waters were occupied by the highly saline return current; beyond
this came still more highly saline subtropical water. In this lay a wedge of even more
saline water (>35-25°/,,) which may be identified with the warm-water wedge (see
D XIII 8
164 DISCOVERY REPORTS
Fig. 33) described on p. 134, and this may perhaps be tropical water and a counter-current
(see pp. 161 and 129). The fact that in this section the values of >34:90 °/,, in the return
current did not extend farther away from the land than 110 miles fit the deductions
made in regard to lines of less length, that the return current is a coastal phenomenon.
CALLAO
Off Callao the sub-Antarctic water is scarcely recognizable as a distinct layer. Obser-
vations at a depth of 60-80 m. at Sts. WS 669, 670 and 671 show a layer where the salinity
is rather less than the values on each side, and this together with the comparative homo-
geneity of water between 50 and 150 m. are the only signs of a depleted layer. ‘The
absence of easily distinguished water layers, together with the warm highly saline wedge
coming close to the coast, makes the interpretation of isohalines in Fig. 44 uncertain;
the possibility of their confirming the conclusions drawn from temperature, that sub-
sidence is in progress, is discussed on pp. 200-201.
GUANAPE ISLANDS
The section illustrating salinity distribution off the Guanape Islands is typical of
upwelling in evenly stratified water, and isohalines resemble isotherms. The com-
parative homogeneity of the upper layers may be taken to indicate that the subtropical
water has been mixed with the lower layers by upwelling, and that the highly saline
warm-water wedge is away from the coast (see Figs. 48 and 16).
LOBOS ISLANDS pie at page area wpe jizeao
Salinity here shows even greater homo- 7
geneity inshore, together with greater
dilution of the upper layers. In this re-
spect the lines off the Guanape Islands,
Lobos Islands and Punta Aguja make a
progressive series (cf. Figs. 48, 47 and
46). A layer of slightly more saline water
lying at the surface within 50 miles of the
shore is shown to have a comparatively
high temperature, and it may be supposed
to be an eddy.
200
DEPTH IN METRES
PUNTA AGUJA
Homogeneity in the upper 400 m. is
carried even further off Punta Aguja.
The appearance of sinking water at 5
miles offshore is not shown by isotherms
which may perhaps reflect a slow speed
of movement. SOUNDING IN METRES. 2277 1485 =
300
Fig. 43. Distribution of salinity. Section off Arica,
June 19-20. The position of the section is shown in
Figs. 2 and 11; the corresponding temperature section
in Fig. 31.
WS664
STATION NUMBERS — WS668 WS6ES ~~ WS670 wse7I WSE67 WSRS6 _WS665- WS66S
MILES FROM COAST 'g0 75 | 50 : 25
|
i004
uv
ud
[ea
-
wi
2 200-
z
a
ne
300-4
400 =o ° FI
SOUNDING IN METRES _ 4285 3840 = 1934 474
Fig. 44. Distribution of salinity. Section off Callao, July 1-3. The position of this
section is shown in Figs. 2 and to.
WS648
STATION NUMBERS — WS653 WS654 ws652 WS65S WwS56 WS6S7 WS646 WSESI —_WS6SO WS549]WS647
MILES FROM COAST 150 ‘es 100 | 7 50! } 25 ' Ure
34.9%
DEPTH IN METRES
400 ——————____ es . . .
SOUNDING INMETRES_. _— = 3840 3315 = — 3147 1264
Fig. 45. Distribution of salinity. Section off San Juan, June 22-24. The position of this section is shown in Figs. 2 and 11.
Temperature sections corresponding to the Figures on this page are illustrated on p. 149.
166 DISCOVERY REPORTS
WS70! WS700WS698
SI
STATION NUMBERS — WS705 WS704 Ws703, ws70e | |WSé |
MILES FROM COAST se "5 ne oa ae a
35:1%0
100
wn
ld
oa
b
tu
=
2 200
xr
FE
a
lo
a
cue" =
300
3493%o
SOUNDING IN METRES 4026 a 4742 3102
Fig. 46. Distribution of salinity. Section off Punta Aguja, July 21-23. The position of this section is shown in Figs. 2
and 12; the corresponding temperature section, in Fig. 36.
CAPO BLANCO
At Capo Blanco, surface salinity is lowered from two causes: at the surface by the
southerly projecting tongue of the Equatorial Counter-current, and from below by up-
welling. The upwelling which is seen in Figs. 41 and 50 to be induced offshore, and the
southerly intrusion of equatorial water seen in the poorly saline hot-water tongue, are
both probably indications of the divergence of the Peru Current from the South
American coast. At a depth of 40-120 m. a mid-water tongue of higher salinity
(35°10 °/,.,) represents an advance of subtropical water towards the coast, presumably
to compensate for the upwelling water.
SANTA ELENA
The mid-water tongue noted off Capo Blanco is drawn both northwards and towards
the Ecuador coast, beneath the Equatorial Counter-current. This may be seen in Fig. 49,
which represents a section in two planes. On the right of the section, Sts. WS 715-719
run east and west off Santa Elena. On the left, Sts. WS 719-726 run north-east by
north and south-west by south, that is, they run very nearly at right angles to those
off Santa Elena: they run across the direction of the Peru Current on its course from
South America to the Galapagos Islands. At this stage the current represents the
transition between the Peru and the South Equatorial Currents. The observations off
SALINITY 167
STATION NUMBERS — WS687 WS688 WSE89 W696 WSESS WSEB4 WOHIS WSES2
MILES FROM COAST 125 190 75 i s0 | = {
: 35:25 = eae
: e * 351%
100 + c
DEPTH IN METRES
34-93%
300-4 - : : a
34: B%o
ae es Ve: 7%e
400 : :
SOUNDING IN METRES_4492 = 2093190! 967 (216
Fig. 47. Distribution of salinity. Section off the Lobos Islands, July 17-20. The position of this
section is shown in Figs. 2 and 12.
STATION NUMBERS _ WS&86 Ws674 ws682 WS681 WS680 | ws678
MILES FROM COAST_ 100 75 50 ;
DEPTH IN METRES
. ——
200
SOUNDING IN METRES_4206
Fig. 48. Distribution of salinity. Section off the Guanape Islands, July 1o-11. The
position of this section is shown in Figs. 2 and 13.
Temperature sections corresponding to the Figures on this page are illustrated on p. 155.
: ‘69 pue 6 ‘sSiyz Ur payerjsnqy]! oe suonoas ainqerodura} sarjoadsar ayy, “12 pue
Z ‘SSI Ul UMOYS d1v SUOI{OaS Asay} Jo UOTISod ayy, ‘spuejs] sosedeyey oy 0} Aem sz UO ysvOd URIATIAg dy} SAARI] I SB JUDIIND dy} SIMO 19}R] IYI,
“P ysndny—r& Ainf (gzZ-61£ gm sig) aud rayjoue ur panuryuos (612-S14 gay ‘sig) vUsTy vIULG Yo UONDIG “AyIUTTes Jo UONGLASIG “6b “317
- 3 ONY M > |< NX3N ONVSXMS =
S3TIW +S SaTIN Oll S3TIW v02
WNa1a VLNYS 440 OINV18 Odv¥I 440 YPNSY YLNNd 440
. . . 5 OOF
o% OE = SS
°%8-bE
n
isl
a4 ooE
=
Y
A,
(x)
[a4
Dm a
me y
(ea) ae
> oo2z 2
O =
uy
C x
pa
uw
Q
ool
|
ae oo ES Sos Se | OS | | Soe \ | SS, | Sol | = 3ONLILY7
SILSM9IZSM ZILSM BILSM 6IZSM O02ZSM |\2LSM 22LSM E2LSM ¢2lSM S2LSM 92/5M — SY3GWAN NOILLWLS
168
SEASONAL CHANGES 169
Santa Elena show the poorly saline water of the Equatorial Counter-current extending
to a depth of about 40 m. Beneath is a mid-water tongue of subtropical water which
may be traced southwards from Sts. WS 719-724, when it comes to the surface.
SEASONAL CHANGES
Opportunities of repeating work occurred twice: the line off Callao was repeated
after a period of seven weeks: and during this period a series of observations was carried
out at one position near Palominos Island. Repeated observations are useful as controls
by illustrating the kind of changes that occur over relatively short periods ; they may also
illustrate the changes due to season and they emphasize the limited usefulness of observa-
tions made at only one time of the year, and even more so of isolated observations.
The repeated observations off the little island rock of Palominos were made on
position 12° og’ 30” S, 77° 15’00” W in 60m. of water; the results are plotted in
Fig. 51. The depths of certain isotherms at various dates are indicated by continuous
lines (the 15°5° C. isotherm by a thickened line). The oscillating nature of the tempera-
ture over the stated period is at once apparent. From June 26 until the middle of the
first week in July the temperature of the whole column of water rose, and at the surface
from 16°85 to 17:33° C. Then followed a sharp reaction, and during the subsequent
ws703
STATION NUMBERS —WS/72e ws708 WS7i4 Ws73 ws7ie a WS7TLWS?10})
MILES FROM COAST — io 0 2s
-35: O%on
—35:05%o
o
WwW
a
BE
WwW
=
Z 200- - a
FS 35:0 %0
ao
WwW
a a a
300 >
400. 3 re :
SOUNDING IN METRES — 4314 = = = (685
Fig. 50. Distribution of salinity. Section off Capo Blanco, July 24-26. The position of this section is shown
in Figs. 2 and 70; the corresponding temperature section, in Fig. 41.
170 DISCOVERY REPORTS
four weeks to August 7 the temperature dropped to less than 15° C. It then rose again,
reaching 15°73° C. at the surface on August 20.
The diagram raises two points of interest, the connection with available wind records,
and the differing composition of the water on July 8 and August 7. On July 8 the tem-
perature gradient from 15-5° C. near the bottom to 17:33° C. at the surface amounted
to 038° per metre. On August 7 the water was cool throughout, the gradient from
14°56° C. at the bottom to 14-88° C. at the surface being about 0-005° per metre.
From this it follows that all the water off Palominos Island on August 7 was upwelled
water and that it was derived from the 14-15° isothermal depth which at this time of
the year off Callao lay at about 80-120 m.
STATION NUMBERS_WS662 WS663 WS672 W584 WS685 ws7e7 Ws726
De | JUNE30 JULY IO JULY 20 JULY 30 AUG IO AUG20
es —
: .
I5s°
10— : Vo Ne
147°
20
w
uw
F 30+ Maa ee
>
148° ‘
zZ 8 Se a
= ao- i ae
a
ra
14 5°
50 . :
149
eqs) UA
62m 62m
65m
Fig. 51. Diagram illustrating temperature changes off Palominos Island in the period June 26 to August 20.
Note. ‘The depth scale is nearly x5 that of the sections; the sounding in metres is given at
the appropriate depth for each section.
Table VII. Relation between inshore surface temperature and
the strength and direction of wind at Palominos Island
‘Temperature ° C. Wind
oe Mean rise Mean fall M Force
per day per day Came Clones miles per day
June 25 | 0-04 — S17°E 43
July 8}
July 8) — 0:082 S 26° E 7:0
Aug. 7{
Aug. z 0:065 = S 273
20
ST stl]
SEASONAL CHANGES igi
A connection between available wind records and temperature changes off Palominos
Island is suggested in Table VII. The eight weeks June 26—August 21 are divided into
three periods each corresponding to a period of rising or falling temperature, and the
amount of temperature change is expressed as the mean rise or mean fall per day. The
winds recorded by the ‘ William Scoresby’ in this area during these periods are expressed
as a mean vector for each period. ‘T'wo possible correlations are to be noted: firstly that
the greater rise in temperature accompanies the least wind force, and secondly that
the cooling tendency follows the wind with the largest easterly component. The wind
records are not as precise as could be desired ; they were made quite irregularly between
STATION NUMBERS — WS734 WS733 ie Wws731 WS730 Reyes lee
|
MILES FROM COAST — 150 eS ' 00 75 50 | es
es
rs eee el
“a SS
ire]
ao
2
z 2004
eke
-
a
W ee ee |
ae ——— ee,
RS eg oy
400—
Fig. 52. Distribution of temperature (° C.). Section off Callao, August 20-21. The temperature section of
July 1-3 is given in Fig. 32.
June 26 and August 21 and in the coastal region between the parallels lat. 10-14” S.
There are no records in the exact neighbourhood for 19 days from July 17 to August 4,
and it may be that records made in harbour bear little relation to winds out to sea. ‘The
means of all these wind records, however, fit the temperature changes, although perhaps
not quite so well as might have been expected from the results obtained off Antofagasta
and the Guafiape Islands. An alternative interpretation is discussed on pp. 209—10.
The line of stations repeated off Callao on August 20-21 differed little in general plan
from that of July 1-3, although the water was generally cooler. The water of 18° and
19° C. had disappeared or cooled down (Fig. 52), but the warm-water wedge was still
to be identified as a trough of water of about 17° C., and the temperature of the open
ocean at 155 miles from shore was also 17° C. That the lowered temperature out to sea
DXIII 9
172 . DISCOVERY REPORTS
was partly. the result of vertical mixing is suggested by the greater uniformity of the
upper 60 m. and by the fact that in August water even at 120 m. was warmer than at
corresponding depths in July. Perhaps as a consequence of this lesser stability, up-
welling happens from greater depths in August than in July. The fact that the warm-
water wedge has moved closer inshore and has lost its former sharp distinction is also of
interest. In Table VIII the July and August lines are compared in greater detail.
Table VIII. Seasonal differences in hydrological conditions off Callao
Date 505 ss Soe Abo July 1-3 August 20-21
Length of line... ee 505 103 miles 155 miles
Temperature:
Offshore: surface 18-39° C. nGpuds (Co
120 m. 13°48° C. iia yes (Ce
224 m. 12:00, 1C- 12-0251C-
Inshore: surface 722 aCe nieyB (Ee
Probable depth of water affected o-80 or 100 m. 0-150 Or 200 m.
by upwelling
Warm-water wedge:
‘Temperature 19° C.+ 17° C.+
Miles from shore About 33-65 miles About 14-51 miles
Observations of a seasonal character were also obtained at the conclusion of the
survey on returning southwards in August and September. The surface temperature off
both Chile and Peru was cooler in August and September than earlier in the year. This
cooling is attributable to the effect of winter, but while it holds without exception for
the majority of the coast, the effect was not found between latitudes 34 and 39° S. Here
the surface temperature in September showed a rise over that of May. The comparisons
are made between observations in the same locality on the northward and the southward
journeys and only between those which were separated in time by more than three
weeks: twenty-two such series of observations are available, the broad results of which
are given in Table IX. The rise in temperature between 34 and 39° S may be corre-
lated with the Chilean monsoon, which will be shown on pp. 226-7 to be attended by a
change in the direction of the surface current. This observation, then, enables us to fix
the southern boundary of the Peru Coastal Current.
Table IX. Changes in surface temperature from autumn to winter between 8 and 47° S
No. of Mean weekly
Wate Months compared comparisons change
made “Cs
8-33 May-July 13 —0°23
August
34-39 May 5 +0-01
September
40-47 May 4 — org
September
COLOUR OF THE SEA 173
COLOUR OF “THE CURRENT
Buchanan (1910) has observed that surface water of the open ocean is to be referred
to one of three colour types, ultramarine, indigo and olive green, characteristic re-
spectively of tropical, temperate and polar regions. The colour of coastal waters is, of
course, modified by a variety of causes, and the commonly occurring green in the
Peru Current, like the olive green of the Antarctic, is attributable to an abundance of
diatoms. Since colour is an accepted characteristic of the Coastal Current, it is well
to consider how far our own observations uphold the records already made.
In the neighbourhood of Chiloe, which should be classed as temperate, the water was
definitely green (Plate XVI, fig. 1) at least as far as 60~70 miles from land, and continued
so well to the north of Cape Carranza. Farther up the coast in 25° S, the sea was bluer:
but it had a more greenish look at 6 miles from land where the temperature was low
(14:20-14:45°C.)! than at 10 miles where the temperature was higher (16°79° C.) (Plate
XVI, figs. 2 and 3). But at Antofagasta conspicuous greenness of the water was note-
worthy (Plate XVI, fig. 4): this persisted as far as 7 miles from shore and then seemed to
shade off slightly, but the onset of night prevented our recording the change into
ultramarine, the colour observed on the following day at 46 miles from land (Plate
XVI, fig. 5). A gradual change from green inshore to blue in the open ocean continued
the normal state until the arrival of the ship at Pisco, where water of an almost un-
believable bright salmon colour was found at midday: the vividness somewhat abated
after noon (Plate XVI, fig. 6). The plankton in this region included quantities of a
flagellate pigmented with red, and many of the other organisms such as the Foraminifera
and the smaller Crustacea had oil globules strongly coloured orange. We believe that the
explanation of colour in the sea water lies in these organisms, and it seems probable that
the altering of tone in the afternoon may be due in some measure to vertical migration.
The hydrology of the water is referred to on p. 216 and a possible connection with the
virazon is noted on pp. 210, 232 and 233. Large Medusae, which were noted at other
localities also, attracted attention at Pisco by blocking the ship’s condenser intake;
their numbers made it impossible to keep the intake clear, and the engine-room
machinery was closed down until the moment of departure. Medusae were similarly
abundant at Sts. WS 712 and 713, where they choked the nets and prevented collection
of plankton samples. Their swarming on the borders of water having a high and low
temperature is noteworthy.
At some 50 miles off San Juan streaks of a reddish discoloration were met with, they
were just under the surface of a grey sea and in the fading light of dusk had a brick red
and scum-like appearance.! Individual organisms could not be distinguished in the sea,
but our nets took up an almost incredible quantity of Euphausian cyrtopias in the
course of 5-10 min., affording a parallel to the swarms of Euphausia superba which
sometimes colour the Antarctic with patches varying from ochre to brick red.
On passage from Pisco to Callao the ship encountered changes of colour for which it
is less easy to account. At a point 15 miles off the coast she entered a zone of brownish
1 This record is not illustrated.
174 DISCOVERY REPORTS
water which extended in a north by west to north-north-west direction for 15 miles, as
far as San Lorenzo Island off Callao, where its outer boundary was approximately 7
miles off the coast, and curved sharply shorewards. The southern edge was ill-defined,
being marked by occasional patches a few yards wide of rusty brown foam; soon the
water acquired a full tawny olive and russet colour, and the foam in the wake of the
ship had a rusty appearance. The northern edge, on the other hand, was sharply defined
and lay conspicuous between the brown of the patch and the clear bluish green water
outside (Plate XVI, figs. 7 and 8), their respective temperatures, differing by half a degree,
were 16°85 and 16-34° C. Nets were towed on each side of the boundary at Sts. WS 661
and 662, which were 2 miles apart. In the brown patch at St. WS 662 the scum-like dis-
coloration seemed restricted to the surface, where bubbles and birds’ feathers floated ;
but no connection was discovered either between the surface scum and the multitudes
of the Peruvian cormorant known locally by the name of guanay' which frequent these
parts, or with the shoals of fish upon which the latter feed. The plankton seemed equally
abundant in the clear and the discoloured water. If the excreta of sea birds were dis-
charged into the sea on a large scale they might produce the oily scum, which in effect
bore a resemblance to a surface film of fuel oil. ‘The Peruvian naval base lies near by,
but it seemed unlikely that petroleum was the cause owing to the scarcity of dead birds.
Although the phytoplankton catches were not large and the scum suggested no re-
semblance to the “‘ yellow lenses”’ described by Sheppard (1931) off the coast of Ecuador,
yet the possibility that such a mechanism may have been at work here cannot be
disregarded (pp. 232-3).
Off Salaverry, coastal waters of a conspicuous olivine colour (Plate XVI, figs. g and 10)
extended ro miles seaward: farther from land the hue changed to a sea green, and a
similar sequence from chalky green to blue, always graduated, was observed off Punta
Aguja and again off 'Talara. Near the Guanape Islands irregular patches of khaki were
observed, but the sun set shortly afterwards and their extent was not recorded (Plate
XVI, fig. rr).
A patch of brilliant yellow due to a swarm of a colonial Radiolarian, probably
Collosphaera, was met at some 180-200 miles off Punta Aguja. It was unlike any patch
met close inshore, having more the appearance at a distance of the straw-like discoloration
of the sea described by Collingwood (1868) for Trichodesmium and frequently witnessed
in the Atlantic during the Discovery investigations.
On July 16 at 63 miles from land in 10° 32’ S, over deep water, the sea was the indigo
of temperate regions (Plate XVI, figs. 12 and 14) instead of the ultramarine so commonly
found in the open ocean in these parts, an effect almost certainly due to cloud
(Rayleigh, 1910). On the return voyage from Callao to Valparaiso, two sketches were
made in the open ocean at 255 and 32 miles from land (Plate XVI, figs. 13 and 15).
The former is almost identically the same hue as that figured in Plate XVI, fig. 5,
and is useful as a control; the other has a deeper tint, no doubt owing to the rougher
sea prevailing at the time.
1 Phalacrocorax bougainvillii, a white-breasted cormorant.
COLOUR OF THE SEA 175
The accuracy of Buchanan’s observations is confirmed by our own, made inde-
pendently, and his notes which describe the water as “green”, “chalky green”’,
“olive green” and “‘ultramarine”’ express very clearly the colours in Plate XVI. His
reference to water of a greenish blue off Antofagasta finds a counterpart in our descrip-
tion of it, and the chalky green water found by him off Payta is evidently the same as the
colour we met off Salaverry, Punta Aguja and Talara. His terminology is sufficiently
accurate to warrant the conclusion that he did not come across the patches of orange,
russet brown, and khaki noted in the other sketches. The small distances from the shore
at which chalky green water was found by him agree with our own observations; 5—10
miles is his usual limit, but in his note of greenish water at 15 miles offshore between
Chala and Arica he seems to be describing a hue of ultramarine.
On no occasion during the present survey were cold patches of blue oceanic water
met close inshore as described by Buchanan at Huasco and Carizal. A hypothetical
significance has been attached to these cold “‘ blue patches” because they were supposed
by him and by certain later writers to indicate the presence of recently upwelled water
which, having come from a depth below the layer of active photosynthesis had a minimal
phytoplankton content. According to our own observations, the colour of water which
appeared to be upwelling close under the coast differed in no remarkable way from the
surrounding water; the areas of green, orange, brown, khaki and chalky green all
merging gradually, were suffused with the surrounding waters. The one exception to
this rule, the line of demarcation between water coloured russet brown and that of
porcelain blue off San Lorenzo Island, has already been noted. When we saw the blue
we were convinced that we had come upon a “blue patch’’: closer examination, how-
ever, proved that this could not be so, for the blue water was continuous with oceanic
water to the west, thus its area exceeded that of the brown water and it was not a patch
within the latter. Moreover, the water did not appear to be actively upwelling (see
pp. 170 and 209-10).
EEN THE CURREND
In contrast to the attention that has been paid to the physical aspects of the Peru
Current its fauna and flora have been neglected. Darwin(1845), who spent upwards of six
months on the coast, makes no reference whatever to the colour of the current or to its
marine life. This is surprising in view of its abundance, for it is rich alike in species and
in numbers of individuals. More recently the larger animals and especially those of
economic importance have aroused interest, but little is known of the plankton, the
ultimate source of food of the larger animals and the cause of the colour of the current.
During the present survey collections of phytoplankton and zooplankton were made
over the whole area, but a detailed account will not be possible until analyses are available
and the quantities of the various species have been estimated. In this and the next
section, some results are given which suggest possible correlations with the physical
and chemical conditions. These notes are of a provisional character and are only given
6 DISCOVERY REPORTS
in their present stage because a description of the Coastal Current which took no
account of its marine life would leave much of significance unrelated to the oceanography
of the region as a whole.
Place names on the west coast such as Ballenas Island, Lobos de Tierra, Guanape
Island, and Pescadores Island evince the prominence of whales, seals, birds and fish in
the coastal waters: but Invertebrata were also to be seen, and at night squids were
frequently attracted to the surface by the ship’s lights. ‘The great majority of the larger
animals, like the patches of coloured water, were restricted in their distribution and were
met only within the coastal zone, but squids were as far out as 150 miles from the coast
(Plate XV).
Among the smaller Cetacea, three or four kinds of dolphin were seen. In the Magellan
Straits, Cephalorhynchus commersoni attracted attention partly because of its conspicuous
white body outlined by black pigment on nose, fin, flippers and tail flukes, and partly
because of the quickness with which it takes breath. Farther up the coast we saw por-
poises swimming at a saunter in the calm waters of Coquimbo Harbour, and schools of
dolphin in the open sea. At the time of our visit a whaling company was at work off
Corral and off the island of Huafo in southern Chile, where Humpback, Sei, Fin, Blue
and Sperm whales may be taken; but to-day they are met with in decreasing numbers
and the whaling stations are closing. Of the toothed whales we met six Sperm between
the latitudes of 12 and 26° S, and one or more schools of blackfish (Globicephalus) off
Peru. Of the Whalebone whales, Rorquals were little less restricted than Sperm whales:
five were met in the land-locked Patagonian Channels and a round dozen off the Lobos
Islands; in this region, having the appearance of an eddy, plankton was rich (see p. 220).
Anchovy (Engraulis ringens) also were presumed to be plentiful since, in the presence
of these whales and of bonito breaking surface, flocks of birds at rest upon the water
looked as though they had been feeding.
Seals and birds, as they have terrestrial haunts, were not included in our regular
observations, but a visitor travelling northwards cannot fail to be impressed by their
steadily increasing numbers at every port of call from Southern Chile to the Lobos
Islands; by the sight of pelicans in flight and by his first introduction to guanays in
close-packed flocks that look like black rafts upon the water. We first met them, in
their tens of thousands, at Antofagasta; and behind them pelicans moved slowly,
seeming secure, until the scuttling of guanays indicated the approach of danger (Plate
XV, fig. 2). For the habits of these, the piquero (Sula variegata), the camanay
(S. nebouxi) and the many other species nesting on these coasts, the reader is referred
to The Bird Islands of Peru (Murphy, 1925): see also Plate XV, figs. 1 to 3.
The distribution of sharks is worth noting because they are examples among verte-
brates of the influence of temperature upon the distribution of marine organisms.
A genus believed to have been the hammer-headed shark was in large numbers off
Capo Blanco in the hot tongue of the Equatorial Counter-current (p. 158) but nowhere
else off Peru. Other genera (not identified) were frequent off Chile between latitudes
18 and 36° S, but were not seen farther to the north. The hammer-headed shark, like
PLANKTON 177
the frigate bird which is also of tropical habits, is seldom found farther south than
Talara in the cool water of the Peru Current.
Squids were widely scattered and they varied in size from forms measuring a few
centimetres to others reaching a metre or more in length. A squid which is referred to
Omastrephes gigas by Wilhelm (1930), but which, as far as can be judged! from photo-
graphs, appears to be Dosidicus gigas (Orbigny), was met in great numbers washed up
in the harbour of Talcahuano. We are informed by Dr Ottmar Wilhelm that this
phenomenon may be a serious problem to the harbour authorities, not only because
the floating bodies are so numerous that they choke the harbour and interfere with
shipping, but also because of the disagreeable consequences of their decomposition.
The cause of these cataclysms, which in their effects resemble those of E/ Nino off
the Peruvian coast, is as yet unknown. They are described in more detail on p. 233.
ZOOPLANKTON
Light upon the distribution of the larger animals seems to have been thrown by the
catches of zooplankton. The mass of plankton has been consistently large, but the average
volume per net was slightly larger in the lower latitudes off Peru than in the Chilean
latitudes, as is shown in Table X. The contrast is greater if Euphausians are considered
by themselves. Off Chile, catches of Euphausians were more frequent; they were con-
sistently larger and their bulk occupied a very much larger proportion of the total
plankton catch. Off north and central Peru, on the other hand, the plankton had a small
Euphausian element, but the total bulk was otherwise greater. The krill and the whales
seem to be correlated off Chile; the guano industry, anchovy and heavier plankton, off
Peru. Krill is of course the staple of whale food in the Antarctic: off Corral, whales
have been taken with Euphausia vallentini in their stomachs, but whether in these
latitudes they feed in the proper sense as they do in the Antarctic is doubtful. With rich
plankton off Peru, we find the enormously heavy shoals of anchovy, and upon them the
birds, seals, dolphins, bonito and other animals are said to subsist.
Table X. Relative abundance of Euphausiacea and of other animal plankton off Chile
and Peru as shown by the volume of settled organisms
Total ome Other .
: Total No. of plankton Hupbansigce zooplankton Newet
Latitude plankton mean vol. samples
og mean vol. 1 mean vol. Rais
samples | per sample ie | containing
canes per sample ae per sample = Tes
examined s C.C. Euphausiacea
CHE G.c.
2-14 132 360 25°5 334°5 12*
14-36 155 225 116 109 A2e
* These figures include only samples in which the volume of Euphausiacea exceeds 200 c.c.
1 T am indebted to Mr G. C. Robson for this suggestion.
178 , DISCOVERY REPORTS
PHYTOPLANKTON
Phytoplankton on the west coast is of interest, not only as the link between the pro-
ductivity of the various upwelling centres and the zooplankton, but also in relation to
the green colour of the current. In giving a preliminary account of the catches, we had
no better measurement than the volume of settled organisms. The method based on
chlorophyll estimation, recently introduced into this country by Harvey (1934), was not
available to us in 1931. It is well known that as a result of their different shapes, the
secretion of slime, etc., different species of diatoms pack differently, and that conse-
quently this method can be used only to distinguish major differences in the size of
catches. As, however, catches in the Peru Coastal Current varied in volume from less
than 1 to 390 c.c., the method may be employed with some possibility of success. The
amount of plankton at each station is given in Appendix I as the volume of settled
organisms (to the nearest 25 c.c.), taken by the 50-cm. net from 100 m. to the surface.
When these data are plotted on a chart, the heavier catches are found to occur in
groups; they thus formed areas of concentration and did not seem to be scattered at
random among the poorer catches. Some twelve such patches of higher concentration
can be made out; they were arranged irregularly from south to north and are indicated
in heavy type in Appendix I. While they were more frequently met inshore than off-
shore, four of the patches occurred at more than 30 miles from land off Cape Carranza,
Caldera, San Juan and Callao. This is interesting, since it has frequently been held that
rich phytoplankton is restricted to the green water in the upwelling zone! (see p. 222).
If the mean volume of phytoplankton at varying distances from the shore is computed
from all samples collected during the survey, it is seen to be greatest at 4~5 miles offshore
and less at lesser distances (Table XI). At greater distances the quantity of phyto-
plankton first fell off and then reached a second peak at 56-100 miles offshore. As it
Table XI. Mean concentration of phytoplankton at different
distances from the coast
| Distance from shore No. of Mean volume of
miles observations phytoplankton
<2 9 30°6
253 9 ie)
4-5 13 64-6
6-10 13 42°5
11-25 19 37:0
26-55 24 48-0
56-100 17 75:0
IOI—I50 6 41-6
| 151-200 2 37°5
1 Michael (1921) claims to have identified the seat of greatest phytoplankton production with that of
upwelling on the coast of California. We are not prepared, however, to accept the published data as evidence
on this point, for the seat of upwelling seems to have been situated not in the region where phytoplankton
was examined, but in the neighbourhood of islands at some distance off.
PLANKTON 179
seems likely that, on the average, phytoplankton would reach its maximum development
in one zone, at some fairly well-defined distance from land, the bimodality of this curve
suggests that the area on this survey has been inadequately sampled.
The broad characteristics of the patches noted above, including their position, size,
and concentration, are given in Table XII; the data are insufficient to show whether they
are comparable to the phytoplankton concentrations described by Savage and Hardy
(1935): and if, as appears likely, the area has been inadequately sampled, it is unsafe to
draw far-reaching conclusions. It is interesting to note, however, that the size of patches
increases with the distance offshore. This result would not have been produced simply
by the wider spacing of offshore stations if the heavier catches had been interspersed
with poorer catches, and consequently it may illustrate that patches have their origin
near the coast, in the upwelling zone, increasing in size as they drift out to sea.
Table XII. Size and distribution of patches of phytoplankton met with on the west coast.
At those localities where patches were not recognized, the fact is indicated by a negative sign
l
; | Mean vol.
Distance | Span et of settled Dominant aes Latitude
sacoast | pate | phytoplankton genera eallty:
miles miles | ;
Gc:
— — | -— Chaetoceros Santa Elena O2setiy
<2 2 50 Chaetoceros Capo Blanco 04° 19’
| { Chaetoceros . on |
o-10 10 179 Nensencdirss Punta Aguja 05° 44
i { Coscinodiscus i | On|
5-15 10-15 | 25-50 | Chaetoceros Lobos Islands 07° 05 |
— = | = Coscinodiscus Guanape Islands 08° 47’
5-10 10-20 | 87°5 Chaetoceros |
| : Planktoniella Callao (August) T2200
BAS ne. ace ee ee
— — a — | Callao (July) | 12° 29'
| i Chaetoceros |
ee) tS 5 Thalassiosira Sven TREN (ev eeeteee |
8 oe {| Chaetoceros i 55
45-5 tooo 75 | Rhizosolenia | | :
-~ — -- | Arica 10m 20)
— — -- = Antofagasta (north) Page te!
{ Chaetoceros Ouai
Fpsiisy 8-10 108 Gone ner Antofagasta (south) 23° 54
oe { Corethron | | ;
ee) 3 37°5 | Chaetoceros Caldera 27° 06'
30-50 20 25 Planktoniella | |
| Synedra |
Trichodesmium Paphoe A 5°
— = - Wo eereee Pichidanque Bay 32
| Corethron
| Thalassiothrix
5-15 10 55 | - Chaetoceros
Corethron 3 <p : Gee
| (ees aa So te
35-85 50 | 135 | + Corethron
a | Synedra
180 DISCOVERY REPORTS
A study of the predominant genera composing the catches was made at the time
of their collection by Mr G. W. Rayner to whom I am indebted for Fig. 53 and the
data in Table XII and Appendix I. They show that although a cosmopolitan genus
like Chaetoceros was represented almost universally, many of the other genera were
abundant only in certain regions. Thus we may distinguish between oceanic species
like Rhizosolenia and Planktoniella, and neritic species: and we may distinguish between
species relatively more abundant in the north such as of Coscinodiscus and of Thalas-
siosira and those in the south, Synedra and Corethron. 'To what extent these distribu-
tions change from season to season we have no knowledge.
PHOSPHATE (CONTENT
Analyses of the phosphate content of the sea water were made on nine of the lines.
In illustrating the upwelling of inshore waters the results fall into line with temperature
and salinity records. ‘The general characteristics of phosphate distribution in the oceans
are a high concentration in deep water and a low concentration at the surface, where in
well-lit layers inorganic salts may be consumed during photosynthetic activity of the
plankton. With this distribution our results agree except in those areas close to the shore
where upwelling of water rich in salts has taken place, and here phosphates are in high
concentration at the very surface.
The phosphate analyses were carried out by Mr A. H. Laurie who has plotted the results
in Figs. 40 and 54—61 as the number of milligrams of P,O; per cubic metre of sea water.!
Each figure illustrates the phosphate values in a vertical section running transversely
across the current. The sections may be arranged serially to illustrate a gradual change
from the condition at Pichidanque Bay, where surface phosphates are everywhere at
a minimum, to that at San Juan where rich phosphates occur at the surface for as far as
50 miles offshore. All these sections betray some trace of upwelling close inshore by
the direction of the boundary between the surface waters, where depletion of phosphate
has occurred, and the rich stores of phosphate in the deeper water; this boundary line
is usually a layer with medium phosphate content which runs horizontally at about
50-200 m. but rises towards the surface near the shore.
Unevenness in phosphate distribution probably depends upon three cardinal factors:
upwelling or subsidence of rich concentrations to and from the surface according to
wind, seiche or other conditions; depletion brought about by propagation of phytoplank-
ton; and vertical mixing of the richer and poorer waters through the action of gales and
currents. To these must be added the decomposition of organic remains and salts of
terrestrial origin. The common plan underlying phosphate distribution in the first
seven of the nine sections just described points to upwelling phenomena as the most
influential of these factors, and consequently a correlation is to be expected between the
phosphate distributions and the temperature curves.
* In this work it was found impracticable to filter the samples before analysis. The data were not
salt corrected and presumably include arsenates if present: they are therefore probably on the high side.
DISTRIBUTION OF PHYTOPLANKTON 181
Rhizosolenia
[| Mlanktoniella
4 Cascinodiscus
NS 7halassiosina
LU Synedra
ES Corethiron
Chaetoceros omitted
Lengths of station lines
exaggerated wice.
Fig. 53. Distribution of the genera of phytoplankton as found dominant at each of the localities visited
between May 18 and August 1, 1931.
182 DISCOVERY REPORTS
PHOSPHATE AND - TEMPERATURE
Comparing the temperature sections of two lines which show extremes of high and
low phosphate abundance, Cape Carranza and Pichidanque Bay, it will be seen (Figs.
54 and 55) that upwelling was active or had until very recently been active in the first
within 58 miles of the coast, the temperature rising 2-12° with a gradient of 0-037° per
mile, while in the second there was next to no upwelling except for the first few miles,
the temperature showing no appreciable increase within 74 miles of the shore. The
line off Caldera affords an equally good illustration (Fig. 56). The line may be resolved
WSSS3
STATION NUMBERS_WSE60! WS600 WS593 WS538 WSSS7 WS596 WSS85 WS554 |
25
MILES FROM COAST ' 75 50
* 40mm b ji
oy : _8OmmG ‘
BOmmG
200
DEPTH IN METRES
300
400 . : . :
SOUNDING IN METRES__ 5497 = 3265 2307 (593
Fig. 54. Distribution of phosphate (per m.*). Section off Cape Carranza, May 18-20. Corresponding
sections of temperature and salinity are illustrated on p. 138.
into two parts: within 25 miles of the shore turbulence and upwelling seem phenomenal ;
from 25 to 50 miles offshore the isotherms run level. Corresponding to these two parts
we find that surface phosphate values in the upper layers from 25 to 50 miles are mini-
mal, whereas in the upwelling region they are medium. Moreover, rich phosphates are
nearer the surface in the upwelling region than offshore. Off Antofagasta the phosphate
content at the surface changed from rich to medium with change of wind and increase
of temperature (Figs. 58 and 59). Off San Juan, the surface temperatures over the
regions of high, medium and low phosphate concentration are respectively 13°79—15-36°
C., 16-24-17-4° C., and 18-80-19:48° C. Correlation between phosphate distribution
and temperature in these five localities is straightforward because the area of disturb-
PHOSPHATE AND TEMPERATURE CORRELATION 183
ance was amply covered by our stations. Off northern Peru, however, the breadth of
cool water is greater and observations do not always extend through to typically oceanic
conditions. Thus rich phosphates at the surface near the Lobos Islands may be corre-
lated in their wide extent with the spreading seawards of the surface isotherms; but the
contrast between waters that have long been at the surface and those recently upwelled
is not illustrated (Fig. 60).
PHOSPHATE AND PHYTOPLANKTON
The relation between nutrient salts and phytoplankton may be shown in two ways,
firstly by the occurrence of rich phytoplankton only in those areas rich in nutrient salts,
WS605___WS603
STATION NUMBERS_WS607 WS606 WS608 ws609 WS6I0 | WS804 | W602
MILES FROM COAST is 100 7S 5p 25
\00--
DEPTH IN METRES
1296 687
Fig. 55. Distribution of phosphate (per m.*). Section off Pichidanque Bay, May 28-30. Corresponding
sections of temperature and salinity are illustrated on p. 139.
400—- x Ey :
SOUNDING IN METRES __ 3550 = 7 2500
and secondly, within those areas, by the greater depletion of nutrient salts at stations
where phytoplankton is thick than at those where it is poor. Table XI shows that
phytoplankton is in higher concentration within roo miles of the coast than farther out
to sea. The phytoplankton inhabits the uppermost layers, and the uppermost layers are
rich in nutrient salts only close to the coast. Thus regarding this part of the eastern
South Pacific as a whole we note that phytoplankton and phosphate coincide in abund-
ance along the coastal region. This coincidence in the distribution of phosphate and
phytoplankton is seen to almost greater effect when the separate localities represented
by our lines of stations are compared with one another. The seven lines upon which a
complete series of phosphate analyses was secured have been arranged in order of
184 DISCOVERY REPORTS
increasing plankton yield in ‘Table XIII. The correlation between poor plankton (plant
and animal) and poor phosphate, and rich plankton and rich phosphate presumably
illustrates the restrictive law of population.1
Table XIII. Correlation between volume of plankton and concentration of phosphate
Plankton
mean volume per station Phosphate
Locality
SETUIS De Zooplankton Ganz Breadth of zone
c.c Ce: miles
Guanape Islands <25 405 Rich 15
Lobos Islands <25 395 Rich 40-80
Cape Carranza 76 313 Rich 70
San Juan 51 208 Rich 50
Antofagasta 25 276 Rich 25
Caldera 18 172 Medium 20
Pichidanque Bay Very few 113 Poor —
Rich= > 80 mg., Medium = 40-80 mg., Poor= <4o mg. P,O; per cubic metre.
In reviewing the phosphate concentrations on these lines, no reference has yet been
made to the minor irregularities such as occur off Cape Carranza, Antofagasta and San
Juan, where patches of phosphate reduced to a medium value may be met at or near the
surface layers in the midst of higher concentrations; nor to the fact that rich as may be
the phosphates at the surface in the upwelling region they are usually less rich than those
in lower layers. The possibility of relating
this reduction to the activity of phyto-
plankton may now be considered.
Off Cape Carranza two patches of dense
phytoplankton were met: one was situated
at 5-15 miles from the coast, the other
offshore from 35 to 85 miles, and neither
at first sight shows a direct relation to the
amount of phosphate in the surface layer
and to the patch of medium phosphate
illustrated in Fig. 54. We may endeavour,
however, to measure the reduction of
surface phosphates by comparing these
values with those in deeper water, say at
too m. In this comparison the mean of
the valués at o and 20 m. may be expressed 300-4
as a percentage of the mean of the values
WSE6I8 WS6!5 W563
STATION NUMBERS_WwS6i2 ue se uisbcd WSB17| WSBI6|WS5I4
(2
MILES FROM CoasT_ |! 50
100 4
200
DEPTH IN METRES
1 The low values of phytoplankton off the
Guanape Islands and the Lobos Islands may be
due to over-cropping of the animal plankton, here
. . O 5 400- . 7 . q .
in its highest concentration. SCUNDING IN METRES__ 5861 4864 — 303! 1768 1132
Fig. 56. Distribution of phosphate (per m.°). Section
off Caldera, June 4-6. Corresponding sections of
temperature and salinity are illustrated on p. 142.
WS643 WS647
STATION NUMBERS =WSE53 USES: wsb6S2 wisess (ESE wes? WSEA6 WS651 WSESO W648
MILES FROM COAST — IS0 '¢5 igo 7S 50 -
< BO MMG.
w
WwW
a
B
S
* 20 > 5 5 é
ae
=
a
Wu
a
2205)
400—1—. : . : : :
SOUNDING IN METRES_ — = 3840 3315 = — 3147 1264
Fig. 57. Distribution of phosphate (per m.*). Section off San Juan, June 22-24. Corresponding sections of temperature
and salinity are illustrated in Figs. 33 and 45.
WS627 WS625 WS623 WS632WS634
STATION NUMBERS WS629 WS630 WAI WS ws6z2 STATION NUMBERS_WS629 WSE30 W531 SRE W565
MILES FROM COAST. 50 ' 25 MILES FROM COAST_ | 25
{i} <GOmys | ; :
1
X<60umG | | : ;
!
1
i}
BOMMG : |
a | 8Ommc
100 -G 1004 .
wo
a a
: :
= 2004 = 200, - é
z z
ae
a, =
wi wi
a
3004 300-4 .
200 400 9 é ree
SOUNDING IN METRES- 7159 = 204038608 SOUNDING IN METRES_7159 = = = 7a
Fig. 58. Distribution of phosphate (per m.*). Section Fig. 59. Distribution of phosphate (per m.*). Section
off Antofagasta on the outward journey, June 8~9. off Antofagasta on the return journey, June g—1o.
Temperature and salinity sections corresponding to Figs. 58 and 59 are illustrated on p. 143.
186 DISCOVERY REPORTS
at 80 and 100m., for each station. These percentage values are compared with the
corresponding phytoplankton catches in Table XIV. The mean of the percentage
reductions for each value of the phytoplankton shows a correlation; and, if we may
suppose an interrelation at some earlier date between upper and lower layers, it may
be said that off Cape Carranza the volume of the phytoplankton varies inversely with
available phosphate.
Table XIV. Relation of phosphate reduction to volume of phytoplankton
| 1
Cape Carranza Antofagasta San Juan |
Phosphate Phosphate Phosphate
Phyto- reduction Phyto- reduction Phyto- reduction
St. | plankton |—————_|__ St. |} plankton |—>——————||__ St. | plankton
vol. c.c. Py, Mean vol. c.c. aw) Mean vol. c.c. Fs Mean
/O O/ /O oF %o of
/O (9) 0
592 <25 22 Bp 622 <25 5) 652 <25 go
596 <25 rf at 623 <25 41 | 654 <25 — On
593 25 350 935 624 <25 39; 32 653 <25 92
594 75 4 see MC SS 3°| 646 | <25 a a5
595 75 33 630 <25 45) 651 <25 15
599 100 40 40 626 75 46 = 46 650 12 2 2
600 125 AG) AG) | G25 100 BH 0) 647 25 fo)
597 150 55 627 150 47 47 648 25 of 0
598 150 50r 57°3 649 25 °
601 150 68 657 75 4 4
655 150 66 66
656 300 32 ese
| | : I
Surface phosphate is measured against the value at 100 m., and the difference, expressing reduction, is
given for each station as a percentage of the latter (see text, p. 184). The stations of each line are arranged in
order of increasing phytoplankton yield and for stations of similar yield the figures expressing phosphate
reduction have been averaged. The figures in heavy type represent observations made in the region of the
highly saline warm-water wedge. At Sts. WS 591 and 628 the 5o-cm. net was not fished.
The lack of phosphate off Pichidanque Bay has been attributed to an absence of up-
welling; on this line the phytoplankton is also meagre, and if the presence of thick
phytoplankton is regarded as evidence of an earlier abundance of nutrient salts, its
absence here indicates that upwelling has probably not taken place for some considerable
time.
The small quantity of phytoplankton and the hydrological conditions agree in showing
that at Caldera upwelling was of recent date. The high temperature and the minimal
phosphate at the surface on the seaward part of this line makes it probable that recent
conditions had been preceded by a period of prolonged calm. On the other hand, the
water is homogeneous to a depth of 50 m., which is evidence that the calm period was
followed by winds of a strength sufficient to cause extensive vertical mixing in the
upper layers. The recent occurrence of these winds is consistent with the upwelling
inshore; while the fact that upwelled phosphates were diluted and the fact that in
PHOSPHATE AND PHYTOPLANKTON INTER-RELATION 187
STATION NUMBERS_WS687 WS6BB8 ws689 wWS696 WS69S WS634 wS693 WS692
MILES FROM COAST — 125 100 75 ' so . e
| ! !
a ;
. a .
BOmmG a
1004 ° °
wn
w
(ea
FE
Wi
=
2 2004 - . 2 . .
I
=
a
to
a
300-4
400 : z : . : :
SOUNDING IN METRES_4492 me 2093 901 367 l216
Fig. 60. Distribution of phosphate (per m.%). Section off the Lobos Islands, July 17-20.
STATION NUMBERS__wWS686 WS6 74 ‘S680
MILES FROM COAST! 100 75 | 0 Pies
| | |
= \ ee.
"40mmo
1004
DEPTH IN METRES
200 : =
SOUNDING IN METRES— 4206
Fig. 61. Distribution of phosphate (per m.*). Section off the Guanape
Islands, July 10-11.
Temperature sections corresponding to the Figures on this page are illustrated on p. 155;
salinity sections, on p. 167.
Ir
D XIII
188 DISCOVERY REPORTS
this zone phytoplankton catches were small together suggest that this upwelling is of
very recent date.
At Antofagasta, a patch of phytoplankton having a high concentration was crossed in
the area of cool upwelled water rich in phosphate 7-15 miles offshore. The three
observations in the phytoplankton patch (Sts. WS 625-627) show a decrease in phos-
phate from high to medium values, whereas at the same stations at 80-100 m.
phosphate values are high (Table XIV). In the poorer water offshore and in the poorer
water of the second Antofagasta line, no phytoplankton patches were recognized.
In its relation to the distribution of phytoplankton, the percentage reduction in
surface phosphates off San Juan conforms with the conditions met with off Cape
Carranza and Antofagasta (Table XIV) except for an apparent reduction of 91 per cent
at Sts. WS 652-654 in the highly saline warm-water wedge where the phytoplankton was
negligible. The anomalous condition at these stations is explained if the water of the
wedge has an oceanic origin and unlike surface water closer inshore has not arrived,
recently at any rate, by upwelling. This suggestion receives some support from the
species composing the phytoplankton: for whereas the inshore stations were rich in
Chaetoceros, Thalassiosira and Rhizosolenia, at Sts. WS 652-654, these genera were
replaced by Planktoniella.
In regard to the lines off northern Peru, we have unfortunately no phosphate data off
Callao and Punta Aguja where alone exceptional catches of phytoplankton were made.
Phytoplankton in the catches off
the Guanape Islands, Lobos Islands
and Capo Blanco was comparatively
poor, but the nets contained a con-
sistently rich zooplankton fauna.
These results may be summarized
(Table XV and Fig. 62) by com-
bining the data off Cape Carranza,
Antofagasta and San Juan and
averaging the percentage figures ex-
pressing depletion for stations of
different phytoplankton concentra-
tion. The method and the results
are discussed on pp. 218-19. It will
have been noted that data from other
oO
x
4
PHOSPHATE REDUCTION
S
Se
lines do not lend themselves to pre-
liminary treatment in respect of the
detailed or more intimate relation
between phytoplankton and phos-
phate, and that this is because either
> ele
100cc 200cc 300cc
PHYTOPLANKTON — SETTLED VOLUME
Fig. 62. Graph relating phosphate reduction to volume of
phytoplankton: off Cape Carranza, Antofagasta, and San Juan.
For explanation see text and Tables XIV and XV.
the phytoplankton is poor and our measurements are not representative or the phosphate
data are incomplete.
CONCLUSIONS—NORTHERLY CURRENT 189
Table XV. Summarized relation of phosphate reduction to volume of
phytoplankton off Cape Carranza, Antofagasta and San Juan
Calculated reduction
Phytoplankton
acd Sal: No. of of surface phosphate Notes
Ces observations (mean value)
Giee
25 13 21 ? reduced by zooplankton
25 4 9
75 + 22
100 2 38
125 I 46
150 5 LyY/
300 I 32 ? value of settled volume
The data in this table are computed from the figures set forth in Table XIV. Data collected at Sts. WS
652-654 in the region of the warm-water wedge have been omitted.
CONCEUSIONS ON THE RESULTS OBTAINED
CURRENT
The surface circulation on the west coast needs to be examined more fully than has
been possible on the present survey before an exhaustive account of the region can be
rendered. The water-masses composing the uppermost layers share in the anticyclonic
gyratory movement of the eastern South Pacific; but throughout our results run
evidences of larger and smaller eddies which give rise to counter-currents of supreme
importance to the coastal biology. At the surface this movement has been recorded
directly by the set and drift of the ship, and indirectly by other hydrological data.
Movement beneath the surface has been inferred by indirect means only.
NORTHERLY CURRENT
SurFACE Current. A study of the ship’s drift has been made on pp. 125~133, where
it was shown to be northerly at irregular intervals, greater inshore with a mean north-
ward velocity of ro-12 miles a day than at a distance of 100-130 miles, where the mean
northward velocity was only 34 miles a day. Seldom was there a sudden change from
the zone of heavier drift to that of lesser, but the mean values over the whole coast
showed a slow diminution with increasing distance from shore. Winds, on the other
hand, are stronger offshore than inshore. It follows that the influence of current on the
drift of the ship in a direction parallel to the coast is greatest inshore.* It is reported
that steamers take one-tenth longer on a given run going south than going north, and
that near Antofagasta fishermen find difficulty in working southwards under sail (Coker,
1918). It is of historical interest, too, that Betagh, when masquerading as a Spaniard in a
prize captured off the Peruvian coast, was challenged by an enemy vessel and he used
1 See footnote on p. 1go.
190 DISCOVERY REPORTS
plausibly the adverse current as an excuse for failing to arrive in Lima (1728, pp. 242—
243). Such is the accumulated experience of navigators, but northerly current, like
other currents on this coast, was pre-eminently irregular in its occurrence, a fact which
will have been noted in earlier sections and which, if borne in mind, will assist inter-
pretation of the hydrological conditions.
According to Ocean Passages of the World (Somerville, 1923) the speed of the current
is 0-30 miles a day off Chile and 10-25 miles a day off Peru; and according to Derrotero
de la Costa del Peru (Stiglich, 1918), the current can be neglected except in two places,
along the south coast of Peru northwards of Mollendo, and between Eten and Punta
Aguja. Our experience was much the same, and in this connection, the absence of current
off Callao which lay between these two centres is important, and seems to be a not
infrequent condition. Dinklage, while finding no current inshore at Callao, recorded
westerly set offshore (Schott, 1891).
Since winds offshore are stronger, and more closely approximate to the south-east
trade, the lessening of northerly current with distance from shore is probably accom-
panied by an increasing set towards the west. The present survey gave few oppor-
tunities of observing current other than parallel to the coast, but the universality of
upwelling off both Chile and Peru is evidence that westerly set of the surface layers was
in progress and was widespread. It was especially pronounced off northern Peru
(‘Table I), the region where it is known to be characteristic (Garcia 1870, and the South
American Pilot, 1927); and it was also recorded by us off Antofagasta in the presence of
easterly and southerly wind. It was not, however, ubiquitous, and off the Lobos Islands,
San Juan, and Antofagasta (return journey) easterly set was met. The circumstances in
which easterly set was found suggest that it was of localized rather than of general
occurrence, and that it is usually bound up with eddies (e.g. off Antofagasta see pp.
127 and 208, and off the Lobos Islands pp. 131, 164 and 220).
Deep Current. At the time of this survey, the convergence of sub-Antarctic water
and subtropical water in the meridian of 71~72° W. lay in 24-26° S. Although records
of surface drift give little evidence of northerly current! in the sub-Antarctic water, a
study of salinity shows that the sub-Antarctic water extends northwards beneath the
subtropical water for some 10° of latitude: this has been shown on pp. 161-2 to differ
markedly from conditions in the South Atlantic where sub-Antarctic water returns
southwards shortly after meeting the subtropical water. Until the flow of subsurface
layers has been determined, the implication of this northerly extension of sub-Antarctic
beneath subtropical water on the west coast can be put forward only tentatively. Con-
1 Tn these and other data, the strength of current is obscured by the difficulty of differentiating between
the effect of current and the effect of wind on the drift of a ship. Observations of current based on
discrepancies in the observed and calculated position of ships are easily vitiated by the effects of wind,
and windage cannot be recorded accurately because it varies daily with every ship (Lartigue, 1827, p. 21).
Only a ship which had steamed across the usual direction of the current or had been able to use a current
meter would have realized, for instance, the immobility of the water and the full extent of the wind met by
us off Pichidanque Bay; and in view of the prevalent weakness of the current on the entire coast, it seems
probable that popular belief in its strength may be exaggerated.
CONCLUSIONS—COUNTER-CURRENTS 191
sideration of the fact that the surface water moves away from the coast towards the
west, suggests that layers below move toward the east to compensate for the water
which is welling up (Schott, 1891, p. 215): this is suggested too by isohalines in Figs.
47, 49 and 50. If this is the case, the northerly extension of sub-Antarctic water beneath
subtropical water may be regarded as a mid-water current of compensation associated
with the coast.
SOUTHERLY.CURRENT
SuRFACE CurRENT. Southerly current close against the coast, to which references
are very frequent in the literature, was met off Capo Blanco, Antofagasta and Caldera
(Figs. 14 and 15, and Table I). Inshore of the Lobos Islands, the distribution of surface
salinity suggests that a similar coastal counter-current may have been present. ‘These
counter-currents were of small dimensions and were seldom more than 2-3 miles in
width; we have in consequence few data relating to them. They occurred in regions
where water movement, and especially movement towards the north and west, was con-
spicuous and where, therefore, upwelling on a corresponding scale might be expected.
In the neighbourhood of the counter-currents, however, upwelling was locally allayed
and the counter-currents seem to have been in part currents of compensation. They are
thus seen to constitute a series of eddies and are probably such as may be found on any
coast. These eddies are cyclonic and the convergence of the counter-currents with the
coast is presumably an expression of the tendency to deflect cum sole. At Caldera the
surface drift is illustrated diagrammatically in Fig. 8, while the depth reached by an
eddy-like mass of sinking water is illustrated by the section in Fig. 23.
Records of southerly drift at some distance from the coast do exist but are
fewer (Frezier, 1716; Juan and Ulloa, 1748; Belcher, 1843; and Stiglich, 1925):
according to Romme (1806):
Prés de cette cdte, les eaux se dirigent au N, tandis qu’au large elles s’avancent vers le sud.
A Arica suivent Frezier, les courans, en été, portent au N et au NO; mais en hiver, au sud. Devant
Callao et dans les parages voisins, on a observé, au large, un courant dirigé au sud, tandis que le long
de la céte, les eaux s’avancaient dans le nord.—-A 8o lieues en mer, entre les paralleles de 15° S et la
ligne, et méme jusqu’a 15° N, les courans portent généralement a ouest, et ils s’avancent dans le sud,
sous des latitudes plus grandes que 5° sud.
A highly saline warm-water wedge which during the present survey lay in the open
ocean was well away from the coast, had a breadth of some 50 miles and seemed to extend
along the greater part of the Peruvian coast; it was thus of considerable dimensions
(Fig. 16). High salinity and temperature and a breadth which varied little were the
distinguishing characteristics of this wedge, but southerly flow was recorded off San
Juan and off northern Peru. Upon these facts, the conception of a counter-current
based, though its acceptance as a continuous counter-current leaves much to be
explained. Moreover, the observations in the wedge off Callao and San Juan, are
separated by about 270 miles, and in this distance no data are available except close
to the coast.
192 DISCOVERY REPORTS
The continuity of the wedge from north to south cannot therefore be substantiated,
and the alternative, that more than one wedge is in question, calls for examination.
A comparison of the temperature and salinity sections off Callao and San Juan (Figs. 32,
33, 44 and 45) shows a similarity in the structure of the wedge off each of these
localities which would be hard to explain if the water were supposed to flow from one
to the other. The two localities are separated by some 270 miles. While strong southerly
current was recorded in the wedge off San Juan, none was noted off Callao, and it is
unlikely that in travelling this distance the temperature, salinity and general structure
of the wedge could survive so little altered.
From a theoretical standpoint, also, the wedge if it experienced a flow southwards
from Callao to San Juan should tend to deflect to the left and to converge with the coast,
and after leaving Callao would not presumably swing to the right into the open ocean.
Moreover, the presence of the warm water close inshore at Callao and Arica, and the
way in which surface isotherms slope inwards towards these localities from the open
sea, suggest that off Peru two wedges are involved (see Fig. 63). The serial continuity
shown by salinity (Table VI, p. 161) from one wedge to the other, while it may be regarded
as supporting the notion of a single counter-current, might equally be applied to the
hypothesis of two counter-currents, showing them to be homologous, to be drawn from
the same water mass but from different latitudes.
The two wedges are seen to lie off strips of the coast—off northern Peru and north-
wards of Mollendo—where northerly current and westerly set are notorious. Northerly
drift and westerly set in these localities were not only noted by direct observation during
the present survey, but could be inferred from the prevalence there of cool upwelled
water shown in Fig. 63. The wedges flowing south-east and converging with the coast
immediately to the southward of these two centres imply the existence of two large
anticyclonic swirls.
According to this view, the first wedge was converging with the coast northwards of
Callao to compensate, in part, for the strong current off northern Peru. Corresponding
to this, the second wedge, some 5—10° of latitude farther south, also originating from the
open ocean, was converging with the coast in the Bight of Arica to compensate in part
for the strong current off the San Juan-Mollendo region.
Evidence of an indirect nature suggests that the swirls may be a recurrent if not a
permanent feature of the coastal current. Attention has already been drawn to the fact
that coastal current is traditional between Eten and Punta Aguja and in the Mollendo-
San Juan region (Somerville, 1923); likewise westerly set (South American Pilot, 1927,
Part 111; Ray, 1896); attention has also been drawn to the frequent absence of current at
Callao and Arica (Buchanan, 1886; Schott, 1891). Schott (1931) has shown that the
former localities were foci of strong upwelling, whereas the latter were regions of high
temperature in 1927 and 1929 (see pp. 214-15). In view of the conclusions reached on pp.
229-33 that the unusual colours of the sea met by us off Pisco, Callao and the Guanape
Islands were a form of aguaje and may have been a result of the convergence of the
wedge with the coastal water, the appearance of aguaje during winter months described
8p* 75°
Se ooo ee)
Senacserceesoseses!
4 Panta Aguja
ey
ae: Is x
eS
eh
om
oe See Se ee en Se ee en renee ew eeresees
aig ST
a
a
“& San Juan
q
a}
q
a
a
i]
]
a
H
“hh
a
a
q
q
a
a
|
4
4
a
t
1
a
]
(|
a
a
4
a
'
r)
r]
a
a
a
q
0
a
41
ql
t
a
q
|
'
'
ie
0
(
ft
1
t
!
1
|
t
y
ty
ft
a
a
!
'
1
1
|
(
4
1
q
q
r
1
|
|
|
a
"|
(j
is
a
r
8
r)
a
r)
a
8
8
DS)
©.
So
Fes
Fig. 63. Distribution of surface isotherms off Peru, June to August, 1931; as suggested by the evidence for
two warm wedges. The probable existence of two anticyclonic swirls is indicated by the currents, repre-
sented in the figure by arrows.
194 DISCOVERY REPORTS
by Raimondi (1891), Lavalle (1924) and Stiglich (1925) might be regarded as due to the
same cause and as evidence of the recurrent nature of these swirls.
Clowes (1933) distinguishes between stationary whirls! such as may be dependent
upon the topographic features of the sea-bottom, and whirls which are not stationary
such as the travelling disturbances that may be met with along a convergence.
The evidence just reviewed suggests that the anticyclonic swirls off the Peruvian coast
have a stationary character. While this may be approximately true, data collected during
the survey point to the probability that the more northerly wedge was first converging
with the coast southwards of Callao, but later northwards of Callao. In this way it is
thought that the isolated patch of very warm water of 19:10° C. in Pisco Harbour
(Appendix IV) and the changes of temperature off Palominos Island (Fig. 51) and off
the Guanape Islands might be explained (see pp. 208-9). Alterations in the size or
position of the swirl would bring about these changes; and as no direct connection with
the sea-bottom is apparent, an oscillation in the position of the swirl, possibly with
changes in the meteorological conditions, may be expected.
It remains to refer to the easterly and southerly drift of the Prussian sloop ‘Mentor’
in 1823. Mentor’s Gegen Drift, as it was distinguished by Berghaus on his chart of
1837, is marked as setting towards the Bight of Arica; but since it was recorded in
approximately 20° 13’ S, 83° 07’ W (Berghaus, 1842), which is at some considerabl€
distance from the Peruvian coast, its identity with the wedge met with during the pre-
sent survey must remain in doubt.
Deep Current. Another current of importance proceeding towards the south is the
return current off Chile flowing between sub-Antarctic water and the Antarctic inter-
mediate water. Having a northerly origin, it is distinguished from these two by a
higher salinity, warmth and poor oxygen content: it seems to be derived from both
subtropical and sub-Antarctic water. The influence of the earth’s rotation may
perhaps be seen in its convergence with the coast, and is, moreover, seen in Figs. 18,
20, 22, 24 and 45 to be a purely coastal phenomenon. This suggests that it may be,
like the extension northward of sub-Antarctic water, a mid-water current compensat-
ing for the water which is welling up. But whereas the sub-Antarctic water above
it is frequently to be found drawn to the surface, this return current, lying below,
was found to be welling up only at San Juan and Antofagasta, areas of exceptional
upwelling.
The various current systems that are shown above to be an adjunct of the Peru Coastal
Current, probably each exert an important influence on the fauna and flora. The pos-
sible influence of the eddy is discussed on p. 220. The return current just described,
whose oxygen has been reduced by the rich life of the inshore waters, may be returning
organisms and their spores towards the south after they have been carried away north-
ward at the surface. The northward extension of sub-Antarctic water brings water rich
' Clowes (1933) refers to a gyratory movement in the Weddell Sea by the term “‘whirl”. The present
writer has taken the term “swirl” from Tait (1930).
UPWELLING 195
in nutrient salts, and the process of mixture with the other layers may be a factor of
importance in the high productivity of these waters.
ORIGIN OF THE COOL WATER
The probability that cool water reaches the surface close inshore by upwelling was
inferred by de Tessan (1844), by Dinklage in 1874, by Witte (1880), Hollmann (1882),
Hoffmann (1884) and Buchanan (1886), because the explanation advanced by Humboldt
(1811) of a cool surface current from high latitudes was obviously untenable. As a result
of Duperrey’s observations (1831), the adherents to Humboldt’s theory claimed for the
current a polar origin, but Bougainville (1837) showed that the water would warm up
if it flowed through so many degrees of latitude. Though the upwelling explanation
has hitherto rested on indirect evidence it is accepted by the majority of modern writers,
but Thoulet (1928), working upon data collected by the Challenger Expedition on her
passage from Tahiti to Valparaiso, attributes the cool water to melted snow carried down
by rivers from the Cordillera; and Wiist (1935), apparently viewing the subject from
a nationalistic angle, makes enhanced claims for Humboldt’s theory.
Three principal views have been expressed on the causes of upwelling. Dinklage
(Schott, 1891, p. 215) maintained that the inshore waters were drawn away from the
coast by aspiration as a result of the action of the trade winds in the open ocean (vide his
observation on current at Callao); and Witte (1880), on theoretical grounds, maintained
that upwelling would result either by the action of the earth’s rotation upon meridianal
current such as this, or by the action of winds blowing off the coast. Buchanan (1886)
tried to establish the latter of these views on the theory of “Trade Belts”. On this
coast, however, winds do not blow off the shore but parallel to it; and the theory of
“Trade Belts” has long given place to the theory of high-pressure centres. Thus
Buchanan’s explanation is easily disproved.
The present work confirms the views already expressed by Schott, and reference to
Figs. 18-61 can leave little doubt that, as a result of wind acting in conjunction with
forces due to the earth’s rotation, the subsurface layers were upwelling or had been
upwelling in every one of the twelve localities examined between Cape Carranza and
Punta Aguja.
Widespread lowering of temperature in the Peru Current is to be expected as a result
of its flow from cooler to warmer latitudes; and cooling by this means must happen in
accordance with oceanographical principles: but consideration of the temperature and
current data suggest that this process is secondary in importance to cooling by upwelled
water.
The charts of surface temperature (Figs. 16 and 17) and the temperature curves in
Figs. 34 and 66 reveal isolated patches of cool water off Payta, Puerto Chicama, San
Juan, Iquique, Antofagasta and probably Caldera, which cannot easily be explained in
terms of northerly transport. These are clearly instances where upwelling has modified
the orientation of surface isotherms. The influence of upwelling may be supposed to be
D XIII 12
196 DISCOVERY REPORTS
more far-reaching than this, since the low temperatures of recently upwelled water are
continually dissipated by admixture with its surroundings.
Inshore current, wherever it occurs, must be a factor of importance in carrying low
temperatures northward: but the evidence examined on pp. 125 to 133 and on p. 190
shows that northerly current is not only irregular but that the inshore water is more
often than not setting towards the west ; and that drift in the open ocean is predominantly
west. Low temperatures near the coast would thus appear to be continually borne off
towards the west, and to be replaced by further upwelling. In this respect, the Peru
Current differs from a current like the Labrador Current which, converging with the
American coast, is probably able to carry water particles and a low temperature for
almost the entire length of its course.
COASTAL UPWELLING
ESTIMATION OF UPWELLING
In order to compare upwelling in different localities, it is first necessary to find a
method of estimating its degree. The method most used has consisted in noting the
reduction of surface temperature as compared with an arbitrary standard. McEwen
(1912), in his investigations of upwelling off California, selects as his standard the thermal
normal for the latitude, which he assumes (p. 261) “‘is the same as the actual tempera-
ture at a point in mid-ocean having the same latitude”. Thus the difference between
the observed temperature and the normal temperature is assumed to be due entirely to
the mixture of cold water from the adjacent ocean bottom with the surface water. The
disadvantage of adopting this as the thermal normal for the latitude has in part been
shown by McEwen himself in a remark on p. 244 to the effect that “The question of the
distribution of temperatures in the sea is so intimately connected with that of the
character of its currents that it is practically impossible to separate them entirely”.
Schott (1931) uses as his standard the mean surface temperature at a distance of 100
miles offshore. This has the advantage that both the temperature here and close inshore
will be subject to the same local major variations: but it is open to the criticism that at
this distance from shore the temperatures are influenced by upwelling off Peru where the
surface isotherms are far apart to a greater extent than off Chile where isotherms tend to
hug the coast. The effect is an apparent reduction in the amount of upwelling off Peru,
because the contrast between inshore and offshore temperatures is reduced. This is
seen by comparing the surface temperature inshore with that at 46 miles offshore both
at Caldera and San Juan. Off Caldera the difference was 3-36° C., off San Juan only
1-46° C.; yet more upwelling seemed in progress off San Juan, for here a greater
volume of cool water was present inshore, and the difference between the temperatures
inshore and at 152 miles offshore was 5:0° C.!
1 Tt is interesting that this effect happens to be largely neutralized by another factor working in the
opposite direction—namely the greater difference, in the tropics, between surface and subsurface tempera-
tures than in higher latitudes. The net effect is to give Schott’s curve a slope tolerably close to the standard
we have chosen.
UPWELLING 197
The standard adopted by both these writers consists of a series of surface tempera-
tures more or less representative of the thermal normal at the surface. With this
‘‘normal”’ is compared the temperature reduction caused by upwelling of lower layers.
This method may be applicable to measurement of upwelling in one place at different
times but not to measurement of upwelling in different latitudes; for at the surface,
temperature has a wider range from high latitudes to low than in the depths from which
upwelling waters originate. There may be a difference of two or three degrees between
the surface and 150 m. in lat. 40° S, but a difference of ten at the equator. Judged by
this method the same amount of upwelling would produce a more conspicuous fall of
temperature in the lower latitude. Vice versa, adoption of the thermal normal at the
upwelling depth is equally unsuitable.
To meet this difficulty a standard has been sought which is in some way related to
the waters inshore. These are essentially a mixture of the deeper waters with those at
the surface. If we knew the ratios in which these two mixed and we knew their re-
spective initial temperatures it would be a simple matter to calculate a mean resultant
temperature and this could be used as a standard. As we do not know these facts, we
have endeavoured to construct an approximately similar curve by averaging the surface
temperatures outside the area of upwelling, e.g. say in 100° W, with the temperatures
at the mean depth of upwelling, e.g. say 150 m.
In Fig. 64 the inshore surface temperatures as observed from Cape Carranza to Capo
Blanco (curve D)! are compared with temperatures observed at a depth of 150 m. on
the one hand (curve A and the interpolated values A’)* and on the other with the
mean surface temperatures in the ocean in the meridian of 100° W (curve C)*. The
slope of the curve D is seen to differ from curves C and A’ but lies somewhere
between them. If, as the result of upwelling, water represented by curve A’ mixed in
equal volumes with water represented by curve C, the resulting temperature could be
,
= os But if the mean upwelling depth lay above or below
represented by the curve
150 m., and if upwelling water mixed with water cooler or warmer than that at 100° W,
or again if more of one mixed with less of the other, then the resulting temperatures
A’'+C :
would of course depart from those shown by the curve ote, A curve of this type
should enable a better comparison to be made than hitherto of the amount of upwelling
in different latitudes, though it will not afford a measurement of the absolute degree
of upwelling at any one place.
DEPTH AFFECTED BY UPWELLING AND WATER LAYERS INVOLVED
Earlier writers have been handicapped by lack of observations beneath the surface,
and those who first advanced arguments in favour of upwelling on this coast, made no
reference to the depth of water likely to be affected. Upwelling of polar-fed bottom
water was implied by Coker (1918) and Murphy (1923), but Sverdrup (1931) has shown
1 See Table XVII. 2 See columns A and A’, Table XVI. 3 See column C, Table XVI.
I2-2
198 DISCOVERY REPORTS
that the Antarctic intermediate layer can be recognized intact in the stations taken by
the ‘Carnegie’ near the coast. The isotherm of 10° C. is found at a uniform depth of
about 320-340 m., both in mid-ocean and near land. As no vertical movement of water
Table XVI. Measurement of upwelling. Data used in constructing a standard curve
to which inshore surface temperatures in different latitudes may be compared
Temperature observations at 150 m. Mean sur
offshore Standard
face tem-
tempera-
F perature ae
Locality Latitude Mean in 100° W
iS)
St. No. We
WS : '
A A C AE
2
Cape Carranza 40 — _— = = 14:6 —
35 600 10°40 : ;
ras oes 10°51 10:2 170 13°65
Pichidanque Bay 32 606 10°52 E é ; :
6 oe 10°56 10°7 18-7 14-7
Cald oe ons 11-20 » = a iP
aldera 27 19 5 : : :
Gis ach 11°83 113 20°5 15°9
Antofagasta 23 630 11°65 ‘ : : :
bap one 11-28 II-9 214. 16°65
20 — — —- = 22°3 —
Arica 19 639 | 12°56 . , : :
638 12-56 12°56 12°4 22°3 17°35
San Juan 15 654 11-98 ; 7 : ,
ee mas 12-14 13'0 22°8 17-9
Callao (July) 12 669 13°03 : , : :
668 an 12°98 13°4 23°2 18-3
10 = = = - = 23°3 =
Guanape Islands 8 686 14°53 14°53 13°9 23°3 18-6
Lobos Islands 6 688 13°51 13°62 14:2 23:3 18°75
ut ae ey 13°74
unto Aguja 5 70 14°21 ’ : ; :
oo ra8e 14:00 14°3 23°3 18:8
Capo Blanco 4 708 14-60 : : . :
ae 15-02 15°02 14°5 23°3 18-85
Santa Elena 2 718 14°79
14° 14'8 23:2 18:
719 14:76 4°77 4 3 95
fo) o — — — 23°0 —
Note. Data in heavy type appear to have been unduly influenced by upwelling and have been omitted
from reckoning.
Figures in column A represent means of the original data given in the preceding column (unpaired data
excepted) and are plotted in curve A’, Fig. 64.
Figures in column A’ were obtained from curve A’, Fig. 64, by interpolation.
Figures in column C are taken from Schott and Schu and include interpolated values, see curve C, Fig. 64.
The standard temperature is the mean of A’ and C.
can take place without disturbing natural stratification, he argues that the extreme depth
likely to be affected by upwelling is 300 m. Schott (1931) associates himself with this
conclusion.
UPWELLING 199
The water layers which are drawn upwards or which reach the surface as a result of
upwelling are shown in the sections illustrating salinity, pp. 138-143 and pp. 164-169.
South of the subtropical convergence, upwelling involved two water layers; sub-
Antarctic water coming to the surface, and the return current beneath showing upward
< &
N a
Bal
fend S
lag CS
es
3 2
ers
<0
oO oe
| |
40's 30's
— CALDERA
— ANTOFAGASTA
° — ARICA
— SAN JUAN
- CALLAO
—GUANAPE |.
—LOBOS Is.
— PUNTA AGUJA
— CAPO BLANCO
— SANTA ELENA
ia’)
>)
5
Fig. 64. Measurement of upwelling. Comparison of inshore surface temperatures (curve D) with tempera-
tures at a depth of 150 m. outside the upwelling zone (curve A’); with surface temperatures offshore in
’
: A'+C ‘
100° W long. (curve C): and with the mean of the two latter, (curve = ): For explanation see text and
Table XVI.
Note. The record marked © in curve D represents the temperature of upwelled water in the Peru
Current, but was obtained at 35 miles from shore. The high temperature inshore represents the Equatorial
Counter-current and is not upwelled water (cf. Figs. 41 and 70).
movement: only at Cape Carranza (Fig. 18) was the latter drawn at all close to the
surface. North of the subtropical convergence, upwelling involved as many as three
layers. The return current featured at the surface at two localities at Antofagasta and
San Juan, where upwelling was unusually strong, and sub-Antarctic water appeared
200 DISCOVERY REPORTS
at the surface at Arica, where it was still recognizable as a distinct layer; elsewhere
upwelling occurred solely within subtropical water. Thus the Antarctic intermediate
water was never touched.
An accurate idea of the depths affected by upwelling is not easily obtained, because
the return current, hugging the coast in the upwelling depths, interferes with the normal
trend of isotherms and isohalines. The coastal character of the return current is sug-
gested not only by our sections, but by the fact that no evidence of it can be found in
the section representing the ‘Carnegie’s’ oceanic stations 60-70. Its shape in section is
roughly that of an elongated isosceles triangle lying on its side. The base is flattened
against the coast, the apex projects into the open ocean between the sub-Antarctic layer
above and the Antarctic intermediate layer beneath. Thus its upper margin slopes up-
wards towards the shore. This upward slope might be accounted for partly by up-
welling, but the possibility of a centrifugal effect as the current pressing to the left,
presses against the coast on its southward flow should not perhaps be excluded. At
Pichidanque Bay, where upwelling was minimal, the upper margin of the return current
sloped inwards and upwards from a depth of about 160 m. out to sea to less than 50 m.
inshore. Where upwelling was more vigorous the upper margin had a steeper slope.
Thus the trend of isohalines in the Figures illustrated on pp. 138-169 while reflecting
the influence of upwelling, is partly determined by the structure of the layers.
In view of the interest taken in the depth affected by upwelling, it will be appropriate
to estimate the depths likely to be involved. On the evidence of isotherms, Figs.
19-41 suggest that upwelling is usually restricted to the upper 200 m., but off Callao
in August, and off Caldera, depths of 280 and 320 m. appear to be disturbed. The
evidence of salinity (Figs. 18-50 on pp. 138-43 and 164-9), which is perhaps more
reliable, suggests that depths exceeding 200 m. are very rarely disturbed. In Table XVII
a minimum and maximum estimate of the depth affected by upwelling at each locality
have been listed: and the estimates based on salinity have been plotted as curves on the
salinity section in Fig. 42. The minimum depth from which water wells up may be
taken as the depth offshore at which salinity values are found to correspond with the
surface inshore salinity. But as alteration of its salinity is inevitable in upwelling water
through its admixture with the surrounding water layers, the depth from which it
arises must be greater than that represented by the minimum chosen. At localities
where mixture may have been extensive, a better guide to the upwelling depth might be
furnished by inspection of the isohalines in Figs. 18-50. ‘The maximum estimates in
Table XVII have been obtained by this method and are plotted in Fig. 42 as a broken
line.
In five of the localities—Cape Carranza, Antofagasta, Arica, San Juan and the
Guanape Islands—the minimum and maximum depths so estimated correspond with
fair precision within 20 m. or so of one another. At these localities the upwelling process
may be supposed to be at its height and to be attended by comparatively little mixing.
On the other hand, at Pichidanque Bay, Caldera, Callao, the Lobos Islands and Punta
Aguja, where discrepancy is shown between these estimates of minimum and maximum
UPWELLING 201
depth, the minimum estimate may have been unduly lowered through mixture of the
upwelled water with its surroundings. This is shown to be probable by consideration
of the state of the hydrological conditions antecedent to our visit. Pichidanque Bay has
been shown to be a locality where upwelling had not been active for some time; and at
Caldera mixing on a considerable scale would have been a natural consequence of the
eddy and the changes of wind noted on pp. 125-7. At Callao, upwelling was not only
allayed, but the inshore water might have been subsiding (p. 209). At these localities the
discrepancy between the minimum and maximum estimates may imply a capacity for
greater upwelling than was observed at the time of our visit. The homogeneity of the
upper layers off the Lobos Islands and Punta Aguja is also evidence that mixture had
been extensive, but whether at these localities upwelling was not at its height, is
uncertain. Thus we see that different depths are affected according to circumstances.
Upwelling brings up water from a depth of 40 m. at least, and more usually 100-130 m.,
and depths of 180-360 m. may sometimes be touched (Table XVII). If the figures are
averaged, the mean upwelling depth is shown to be by temperature 123 m., and by
salinity 143 m., themselves giving a mean of 133 m. The mean minimum and mean
maximum upwelling depths are given in the table.
Table XVII. Showing the estimated depth from which water wells up and the greatest depth
affected by upwelling
Depth affected by upwelling as shown
: by ee halines a heen Upwelled water at surface
Character (metres) inshore
of Length
surface of line 7 Locality
water (miles) Minimum Maximum
offshore = = Layer Fone
Salinity | Temp. | Salinity | Temp. :
— | = SS —— a
110 40 49 |! 360 200 | Sub-tropical 16°83* Capo Blanco
204 126 60 196 100 | ye 16°50 Punta Aguja
128 120 80 160 150 es 17°38 Lobos Islands
110 130 80 130 140 ~ 16:00 Guanape Islands
Sub-tropical - 155 100 80 100 280 - 15°73 Callao (August)
103 40 40 180 100 3 16°61 Callao (July)
152 160 go 160 160 Return Current 13°79 San Juan
53 80 50 100 110 Sub-Antarctic 16°57 Arica
47 188 go 200 200 Return Current 13°93 Antofagasta
56 108 80 180 | 320 Sub-Antarctic 13°10 Caldera
Sub-Antarctic - 12 118 40 210 180 Pe 14°02 Pichidanque Bay
{ 83 128 70 136 200 s 11°45 Cape Carranza
Mean 112 67 175 178 * ‘This temperature was at 30 miles offshore.
SS aa oe a Inshore temperature in Equatorial Counter-
current was 22°62° C.
Mean 89 177
So (ez m.=mean depth of upwelling according to
salinity.
Mean 133 ‘)} 123 m.=mean depth of upwelling according to
| temperature.
The minimum depth from which water wells up is judged by the depth offshore of the isotherm (and isohaline) corresponding
to the value of the inshore temperature (or salinity) at the surface. he maximum depth affected by upwelling is judged by the
greatest depth at which isohalines and isotherms show signs of rising up towards the shore from their normal depth.
202 DISCOVERY REPORTS
The breadth of the zone of actual uprising is extremely narrow compared with the
breadth of the zone influenced by upwelled water, but upwelling does not always seem
to be in immediate contact with the coast. The breadth of the region of upwelling may
be placed variously from 5 miles at Punta Aguja to may be as much as 30 miles offshore
near the Guaniape Islands (Figs. 35 and 37). An example of upwelling at some distance
from shore was found at Antofagasta (Figs. 26 and 28) and possibly also at Pichidanque
Bay and at Capo Blanco (Figs 21 and 41). At Capo Blanco a small patch of water of
less than 17° C. was crossed at a distance of 31-35 miles from shore; it had a breadth
of 4 miles and lay between the tongue of the Equatorial Counter-current inshore
and water of the Peru Current south and west. In this area of mixing and of local
eddies it would be interesting to know whether this cool water had come to the surface
as the result of an eddy in the open sea or had its origin under the coast farther to
the southward (see also reference to Schott’s divergence line, p. 228).
Indirect upwelling by a process of vertical mixing is to be expected not only in the
zone of actual uprising but for many miles westward wherever wind is heavy and the
thermocline not too pronounced (Atkins, 1924), and this adds to the problem of deter-
mining the limit of the zone of actual uprising.
EFFECT OF DIRECTION OF COAST-LINE
Hydrologists have demonstrated by theory (Ekman, 1905) and experiment (Sand-
strém, 1919) the principles that underlie upwelling phenomena, but as Ekman has him-
self stated, conditions in the sea are so complicated that it is impossible to calculate
exactly the motions of the ocean. He has therefore taken a number of type problems in
which some factors as they occur in nature—such as the shape of the ocean basin, the
winds and the distribution of temperature and salinity—have been replaced by simplified
imaginary ones. The principles Ekman has demonstrated may be regarded as tendencies
which sea water in movement will show under various conditions: but conditions in the
sea differ so materially from those postulated in the type problems that any comparison
between Ekman’s theories and our findings should be drawn with caution. Sandstré6m
has emphasized the dynamic importance of isosteric surfaces across which movement
of the water is checked but along which it is facilitated. This report does not seek to
detail water movements beneath the surface with exactitude, and the isosteric surfaces
are not determined. The west coast of South America presents a number of problems,
and various suggestions have been put forward to explain them. It is not inappropriate
to discuss some of these in the light of the results obtained.
After remarking that in 1927 and 1929 the depression of temperature proper to the
Peru Current is greater off Peru than off Chile, Schott states that the boundary between
the two regions lies near Arica, that is where the coast bends suddenly. He states
further that during the ‘Emden’s’ cruise this boundary was particularly well marked ;
with high (normal) temperature and high salinity upwelling seems to have been nearly
or quite absent. His explanation runs as follows: “ Es muss hier infolge der veranderten
Kiistenrichtung fiir eine gréssere oder kleinere Strecke die Stromrichtung zum Land
UPWELLING 203
hin oder parallel zu ihm, aber nicht vom Land weg gehen und damit die Voraussetzung
fiir das Aufquellen von Tiefenwasser wegfallen”’ (p. 168). In support of his statement,
Schott brings forward the similarity between the temperature records of the two ships
‘Emden’ and ‘Nitocris’: these agree in showing that Arica lies in a region where the
inshore temperature approximates closely to that 100 miles offshore.
In July 1931, conditions were markedly different ; offshore temperatures being higher
and inshore temperatures lower than those given by Schott. While it is true therefore
that high temperatures were very close inshore, upwelling was also in active operation.
The ship’s drift in a direction more or less parallel to the coast gave no hint of con-
vergence within a few miles of the shore in the Bight of Arica, the region where
convergence might be most expected (see Fig. 11). The paradoxical conclusion is
irresistible that some divergence from the coast was taking place in a region of
convergence.
The differences between Schott’s data and our own might be explained by the
variable nature of the current or by differences in the type of observations made. The
‘Emden’ and the ‘ Nitocris’ steamed along the current at an unspecified distance from
the shore, whereas the ‘ William Scoresby’ steamed across the direction of the current
and observations were possible at various distances from the coast. The curves plotted
by Schott resemble most the curve plotted by us in Fig. 34 for 2~5 miles from the shore,
and as the cool water at Arica occupied a very narrow band, it is possible that Schott’s
data were collected outside the zone of upwelling.
Murphy (1925), who knows the coast well, contributes some remarks upon the coast-
line. On p. 175 he states: “The coast of Peru... trending sharply to westward from
near the Chilean border, extends far into the ideal course of the Humboldt Current, and
forces the latter to become an actively impinging stream until it has passed the end of
the continental buffer at Point Parina.”’ The data collected on the present survey bears
out Schott’s statement that the west coast constitutes a single-sided divergence line;
the Peru current cannot therefore constitute an actively impinging stream. It will be
shown later (pp. 208-13) that impingement, or convergence, leads to a reduction or
cessation of upwelling.
Trend of coast-line would probably rank as an important factor governing the
hydrological conditions if the winds off the Chilean and the Peruvian coast were
similar. But off Chile winds are predominantly southerly and off Peru south-easterly
(Fig. 4). Off both coasts they are therefore parallel with the shore: and although the
change in the coast-line trend may alter some aspects of the current, it seems to have a
relatively minor influence upon the degree of upwelling.
EFFECT OF SEA-BOTTOM CONTOUR
McEwen (1916), describing the horizontal distribution of temperature along the
west coast of North America, writes : ‘‘ Upwelling of cold bottom water appears to be the
only type of circulation that could produce such a distribution of temperatures. Further-
more, the contour maps (pls. 1-3) reveal a striking correlation between the location of
D XIII 13
204 DISCOVERY REPORTS
these areas of cold water and the submerged valleys or other regions in which the depth
increases rapidly with increasing distance from the coast. For example, the cold areas
north of Point Dune are close to two submerged valleys as shown by the one hundred
and the five hundred meter contours.”
To ascertain the effect of the bottom topography off Peru and Chile, the sections
illustrated in Figs. 18-41 may be arranged according to the mean gradient of the
continental shelf which is assumed to end at the point where the slope suddenly be-
comes steeper. As will be seen from Table XVIII, little correlation can be made out
between this gradient and depression of surface temperature.
The Chilean and Peruvian coasts are not directly comparable and have been listed
separately. Off Peru water is not only more homogeneous, but the shelf is much broader
than off Chile, and the area of shelf whose depth is less than two and a half times
Ekman’s “‘ Upper depth of frictional influence” (2-5 D’) is more extensive off Peru than
off Chile. Off Peru, D’ would work out at about 150 m. for homogeneous water, whereas
off Chile, owing to weaker wind and higher latitude, the depth would work out at about
70 m.
On these grounds one might have expected the restraining influence of the coast
upon divergence of surface current to be less and upwelling to be greater off Chile than
off Peru: the fact that it does not appear to be so suggests that other factors are also of
importance.
Conditions within a mile or two of the beach were not explored very thoroughly.
Although irregularities of the bottom contour might influence upwelling more here than
out to sea, the zone is probably too narrow to have far-reaching effects upon the current
as a whole. Moreover, upwelling in this zone was frequently interrupted by counter-
currents. The data collected on this survey afford no support to the suggestions of
Murphy (1925, p. 162) or McEwen (1912, p. 272).
Table XVIII. Depression of inshore surface temperature at different localities arranged
according to the gradient of the sea bottom in the upwelling region
Chile Peru
| Gradient of | “Gfurface | Gradient of | “of urface
Locality continental | , emperature Locality continental | , emperature
shelf OC: shelf Oe.
Cape Carranza 1: 180 2°20 Guanape Islands 1 : 800 260 |
Arica Tp LZO 0-78 Lobos Islands I : 580 1°37
Pichidanque Bay I: 40 0:68 Callao I : 190 1:69
Antofagasta 8 gio) 2°72 San Juan I : 160 A411
Caldera 1: 20 2:80 Capo Blanco I: 100 2:02*
Punta Aguja Tece7O 2°30
* 'The depression of surface temperature off Capo Blanco has reference to a record of 16°84° C. at 31-35
miles offshore, the coolest temperature beyond the water of the Equatorial Counter-current.
UPWELLING 205
The line off Cape Carranza was situated south of the Juan Fernandez Rise, the others
to the north. Comparison of the upper 300 m., within which the upwelling zone lies,
shows no essential difference between the conditions off Cape Carranza and those off
other localities. The suggestion (Murphy, 1923, p. 67) that the commencement of the
Coastal Current may be determined by the Juan Fernandez Rise cannot therefore be
entertained.
In view of the interest attaching to the possible influence of any island group upon
upwelling, a special investigation of the Lobos Islands was made (see pp. 131, 153 and
Fig. 12). Aline of stations was run both to the leeward and the windward of the Lobos
de Afuera and the isotherms at all depths from both lines were compared. Isotherms
north-west of the islands (1.e. off their sheltered side) showed traces of upwelling in the
upper 150 m., the isotherms of 15°, 16° and 17° showing a distinct hump in the vicinity
of the rocks, whereas on the south side, the exposed side of the islands, the isotherms
showed no disturbance. Signs of upwelling were, however, scarcely detected at the
surface (see Figs. 30 and 12); in the latter, the isotherm of 18° C. is seen to run between
the two archipelagoes, and since this direction is more or less parallel to the coast-line,
nothing unusual is shown. According to the data given by Murphy (1923), in January
1920 the isotherms of 19 and 20° C. close together took an almost identical direction.
Evidence of upwelling is, however, given by phosphate in the upper 60 m. In Table
XIX the data are averaged in the upper and lower layers in each of four regions.
Sts. WS 690 and 691 on the one hand, and Sts. WS 696 and 695 on the other, are at
roughly similar distances from the coast, but the first are off the exposed (south and
south-east) and the second off the sheltered (north and north-west) shore of the islands.
At the former, phosphate values were intermediate between those at shoreward and
seaward stations—a normal condition. At the latter, phosphate was as high as closer
inshore where upwelling occurs. Thus phosphate was richer off the sheltered than off
the exposed shores of the islands.
EFFECT OF WIND
The facts collected during the present survey suggest that upwelling may be caused
both by local and by remote winds. Conclusions on the effect of local wind are drawn
in regions where a change in the wind was followed by changes in hydrological condi-
tions. Winds at a distance are also supposed to be a cause, since upwelling was found at
every locality examined and in meteorological and hydrological conditions which locally
looked the reverse of favourable to it.
Schott (1931) has described the distribution of barometric pressure in its relation, on
the one hand, to a northerly current with upwelling, and, on the other, to a reversal of
the current with an invasion of the coast by hot equatorial water known as El Nijo.
Under normal conditions the south-east trades blow northwards towards a region of
low pressure at the meteorological equator. In their passage along the Peruvian coast
they impart a dry climate and they give rise to the currents conducive to upwelling and
so are the cause of cool inshore temperatures. It frequently happens, however, that
13-2
206 DISCOVERY REPORTS
from January to April, when the trough of low pressure usually associated with regions
north of the Equator shifts southwards, there follows a complete change of wind:
the south-east trades give place to winds from the north; while north-east trades
from the Atlantic blow with increased strength over the Gulf of Panama and enter the
South American Continent as north-west winds. These are monsoon winds and bring
torrential rains to a district whose mean annual rainfall is normally less than half an
inch. A southerly flow of equatorial water from the Gulf of Panama converges with
the Peruvian coast, sometimes reaching as far south as Callao and Pisco, and it raises
the inshore temperature by as much as 10°. The consequences of this to marine
life have frequently been described. But of immediate interest is the simultaneous
appearance of upwelling off the inner part of the Gulf of Panama. During these few
weeks the coast in the Gulf of Panama has the characteristics of a windward shore and
upwelling results. Thus in a region usually bathed by the light hot water of the Equa-
torial Counter-current, a region characterized by conditions which are usually the
antithesis of upwelling on account of the convergence of the current with the coast and
the steep thermocline in the upper layers, a cold current is found welling up and flowing
southwards in the wake of E/ Nifio, and reaching sometimes at least as far south as
the Equator. Schott has already emphasized the interest of this in dynamic oceano-
graphy by pointing out the correspondence between periodical rises and falls of tem-
perature in the Gulf of Panama with inverse falling and rising of temperature in the
Nino region, and the fall and rise of temperature in this region with barometric oscilla-
tions at Puerto Chicama.
Serial records over a number of years at two or three coastal stations make these
correlations possible. Such opportunity is denied to a ship on a brief cruise, but we
were able to record changes in hydrological conditions apparently following changes of
wind in three localities. At all of them upwelling was increased in the presence of winds
from the east and south but diminished in the presence of winds from the west and
north. Other factors were different in each of the localities, which must therefore be
examined individually.
Antofagasta
The change in temperature conditions at Antofagasta, both at the surface and be-
neath it, has been noted on pp. 141-5, and parallel changes in the sections illustrating
phosphate content on pp. 182 and 185. It was shown that on steaming out from the
shore strong easterly and southerly winds were blowing, and the temperature indicated an
active state of upwelling: phosphates at the surface were rich (Figs. 26-28 and 58, 59).
On the return journey the wind had changed to the north, and both cool water and rich
phosphates had vanished from the surface; that is to say, surface isotherms were found
closer to the coast (Fig. 28).
Several mechanisms may have been acting in this change. Such a shift in the position
of surface isotherms would result if the cool inshore water and the warm offshore water
became thoroughly mixed together. Mixing is of course a feature in any region of
turbulence, but such extensive mixing is unlikely in so short a period as two days. Then
UPWELLING 207
LOBOS DE AFUERA
STATION NUMBERS WSE8B WS683_ WSESE WSES5 WS694 WSES3 ~ WSE92
MILES FROM COAST _100 ] 75 Posy | 25! | ]
wo
Ww
a
=
=
= (00
<<
-
a
w
a
Sas
— 200 . —,. . .
LOBOS DE AFUERA
STATION NUMBERS WS688 WSEB9 wse3a0 Ws69!
MILES FROM COAST 100 ! 75 Ye) | 25 !
l ———
poe
i ee a
ee ee ———
uw ee eae
tw
ac
to
= or
zz le (5°
25
=z
5 | SO
Ww 14
is
200 -___—_——. LESS .
Fig. 65. Distribution of temperature off the Lobos Islands, July 17-20. Section showing the possible effect
of the rocks upon upwelling. The upper section represents conditions on the sheltered, the lower on the
exposed side, of the Lobos de Afuera; their relative positions are indicated by arrows. The positions of these
stations are shown in Fig. 12.
Table XIX. Phosphate values around Lobos de Afuera
Milligrams P,O; per cubic metre
Lobos de Afuera
Seaward of rocks - ee - Shoreward of rocks
(SE of rocks) (NW of rocks)
Station 6098 699 690 691 696 695 694 693 692
Depth (m.)
) 69 69 85 85 104 100 96 go 92
20 69 85 85 85 100 108 104, 104. 112
40 69 100 100 100 108 108 127 — —
60 100 104 118 113 104 112 116 —
Mean values
0-20 73 85 103 100
40-60 93 108 108 116
Stations to the leeward and windward of the Lobos de Afuera are compared with those lying closer
inshore and farther offshore. Upwelling off the windward shore of the islands is suggested by the high phos-
phate at Sts. WS 696 and 695, whereas at Sts. WS 690 and 691, no farther from land, it is intermediate
between inshore and offshore values.
208 DISCOVERY REPORTS
the circular drift of the ship from St. WS 630 to 635 on her return journey and the
presence of a southerly counter-current off Bahia Herradura have been regarded as
evidence of a coastal eddy. Less force is probably required to draw surface water for
considerable distances horizontally than to lift deep water even for a short way vertically ;
and it is possible that for a local reason surface water is available here to flow in together
with upwelled water as compensation for the divergence. The wind was rather stronger
off Antofagasta than elsewhere in the vicinity. A coastal inflow of warm water from the
north might, then, have been a factor contributing to the rise of surface temperature
inshore, but a factor of only limited importance. Assuming a constant velocity of 38
miles a day, a breadth of 2 miles, anda surface temperature of 15° C. (‘Table I and Appen-
dix IV), its heat capacity was obviously far too small materially to affect surface tem-
peratures over a wide area. The temperature rise from 13-93° C. on June 8 to 15-31° C.
on June 10 on the position of St. WS 625 at 7 miles from shore, must evidently have
been brought about by some other mechanism.
The theory advanced earlier, that the shift in surface isotherms may have indicated
a subsidence of the cool water, deserves then to be considered. The change of surface
temperature simultaneously with change of wind at St. WS 630 argues a dependence of
water movement on wind: and the vigorous upwelling on the outward journey argues
strong divergence of surface water from the coast. Dependence of the latter on wind
may be inferred as a probability and indeed is to be expected from Ekman’s theory.
From this the southerly wind is to be looked upon as a force capable of raising water
from the lower layers. And as these are heavier than the surface layers offshore, they
may not unreasonably be supposed to sink when the wind fails or reverses its direction.
That this was happening on the return journey may be gathered not only from the
shoreward shift of surface isotherms above noted, but also from the shoreward drift of
the ship during the course of St. WS 630 (Fig. 9).
In our analysis of the conditions at Antofagasta, we are hampered by having no
simultaneous observations outside the immediate neighbourhood. While it cannot be
known whether an eddy in the north co-existed with upwelling in the south on June 8,
we do know that on June 10, simultaneously with evidence of eddy in the north, up-
welling in the south had ceased: the surface temperature at St. WS 625 in the upwelling
area of June 8 was 13°93° C., and after the change of wind it had risen to 15-31° C. on
June 10. Thus while the ship was drifting to the northward and finding warm water off
Bahia Herradura, upwelling in the former upwelling area had definitely slackened and
the surface temperature had risen. This and the fact that changes in surface tempera-
ture and changes in the wind force were simultaneous, lends definite support to the
view that subsidence played some part in this disappearance of the low temperatures.
Guanape Islands
The shift of surface isotherms with change of wind off the Guanape Islands forms an
interesting contrast to the conditions off Antofagasta, since movement was here anti-
cyclonic and not cyclonic. Here during the journey towards the shore (towards
UPWELLING AND LOCAL WIND 209
Salaverry), the wind blew predominantly from the east to east-south-east and the
isotherms of 20, 19, 18 and 17° C. were at 55, 46, 42 and 14:5 miles from the shore
(pp. 152-3). Then the wind changed to south-west and south-south-west, and on the run
seawards from the Guanape Islands on a line not far from the first, it was discovered
that all isotherms had moved closer inshore: the same isotherms were found at 46, 34,
29 and 8-5 miles respectively. As at Antofagasta, divergence and convergence of the
surface water with the coast—of which upwelling and changes of surface temperature
are indices—appear to show some dependence on local wind. Off this coast the south-
east wind is approximately parallel to the shore, and the deflection westwards of surface
waters is again to be interpreted as showing the influence of the earth’s rotation. The
closing of surface isotherms with the coast during the south-westerly onshore wind
shows that the forces leading to divergence had relaxed, and it is possible that sub-
sidence of the heavier inshore water was in progress.
At the same time it is also possible that the cool inshore water was carried away by
current towards the north (Table I), and that the warm offshore water was brought
nearer to the coast through a modification of the anticyclonic swirl described on p. 192.
Reference to Fig. 63 will show that a shift of surface isotherms towards the coast would
follow if—and in fact might be evidence that—the southern end of the swirl and par-
ticularly the convergence of the warm wedge with the coast had travelled northwards.
Movement of the kind might take place with or without simultaneous subsidence of the
inshore water.
Callao
The third illustration is provided by a series of observations outside Callao, off the
island of Palominos, which was visited on eight occasions between June 26 and August
20. The graph in Fig. 51 shows that the observations fall into three periods. During
the first the water at all depths experienced a rise of temperature amounting at the
surface to a mean daily rise of 0-04° C.; during the second period a fall of 0-082° C. per
day; and during the third a rise of 0-065° C. per day. Corresponding with these
changes of temperature the wind direction and force changed too. During the period of
strong upwelling the wind had the greatest easterly component and blew with a mean
velocity of 7m.p.h. During the periods of weak upwelling or of subsidence the wind
blew less vigorously and with a smaller easterly component. Although this, in principle,
tallies with other observations, the change in hydrological conditions seems excessive
when set against the wind alteration.
These changes, together with other data, have been cited on p. 194 as evidence of the
possibility that on or before June 26 the warm wedge was converging with the coast
southwards of Callao. Between July 8 and 11, on the other hand, temperature observa-
tions suggest convergence of the wedge northwards of Callao (vide supra, withdrawal of
cool water from the Guafiape Islands). These data, considered in relation to the
observations off Palominos Island (Fig. 51), suggest that the temperature off Palominos
rose with the approach of the warm wedge from the south and sank with its withdrawal
to the north. Observations after these dates are too scanty to show whether the further
210 DISCOVERY REPORTS
temperature changes off Palominos Island may be similarly related to the position of
convergence of the wedge.
Swirls of the type described must continually vary in size and location in accordance
with distant and local forces: and this should be borne in mind when weighing evidence
of correlation between a wind which was light and the upwelling off Palominos Island,
or again between a wind which is very local such as the virazon and the convergence of
warm water with the Pisco-Callao-Guanape Islands stretch of coast.
The possible working here of a seiche is discussed on p. 212.
Other localities
Other instances of an apparently direct relation between surface temperature and
wind have already been noted; of cool inshore water and south-easterly wind at
Pichidanque Bay (p. 140) and San Juan (pp. 148-51), and warm inshore water with
north-westerly wind off Cape Carranza (p. 135), and in the Caldera neighbourhood
(p. 140). Compare also the seasonal changes noted on pp. 226-7.
At many localities, however, there was an appearance of upwelling in comparatively
calm weather. The evidence at Pichidanque Bay, for example, goes to show that con-
ditions had been calm for many weeks before our observations were made; both
nutrient salts and plankton were depleted and a thermocline was becoming established
at 40-50 m.: yet traces of definite upwelling were present (Fig. 21). Again upwelling
off Callao and perhaps off the Guanape Islands seems heavy for the strength of local
winds. At Arica there was no sign of an earlier meteorological disturbance: calm weather
on this part of the coast is traditional, and out to sea a thermocline at 30-40 m. was
clearly established (Fig. 31). Yet upwelling from a depth of 50 m. was conspicuous.
Evidence of a foregoing period of calm, at Arica and Pichidanque Bay at any rate,
precludes the possibility of interpreting the upward curve of isotherms and isohalines
as subsidence on an extensive scale. These must be examples of upwelling caused by
forces at some distance from the regions under consideration. Such was indeed inferred
by Dinklage in 1874 (Schott, 1891, p. 215) and by Buchan (1895). The latter writes:
It is probable that the great volume of, and distance travelled by, these currents in the broad Pacific
as compared with other oceans directly results in a stronger and more widespread upwelling, accom-
panied with a correspondingly extensive diminution of temperature.
The formation of currents by aspiration is well known and is well illustrated off
Northern Peru where the coastal water off Punta Aguja and Punta Parina is drawn
west-north-west in the wake of the South Equatorial Current (Ferrel, 1860, p. 55).
The strong inshore current of 48 miles a day off Arica, and, in part, the inshore current
off the Guanape Islands, may be supposed to be due to the same cause, for each of
these localities lay to the southward of regions of strong surface drift.
It becomes a question whether a coastal current caused by aspiration in this manner
may not diverge from the coast as a result of the earth’s rotation and so induce up-
welling. In respect of wind-induced current, Ekman concludes:
The most striking result of the coast’s influence is that a wind is able indirectly to produce a current
more or less in its own direction from the surface down to the bottom, while in the absence of coasts the
wind’s effect would be limited to a comparatively thin surface layer.
UPWELLING AND DISTANT WIND 211
Thus the presence of a coast should have a restraining effect on the influence of the
earth’s rotation. Our results off Antofagasta and the Guafiape Islands suggested that
the surface layers diverged from the coast under the influence of a wind parallel to it,
both over deep and shallow water: the restraining influence of the coast on the influence
of the earth’s rotation must then have been partly overcome. The actual conditions in the
Peru Current differ from those employed in Ekman’s type problems, and to this may
be due the apparent lack of agreement. If a current induced by aspiration is at all com-
parable with a current induced by wind, the inshore coastal current at Arica may be
expected to diverge, and on this account upwelling may be accentuated.
Summarizing these conclusions, the current at the Guafape Islands and especially
the strong coastal current in the absence of local wind at Arica are regarded as having
been produced through aspiration of the surface layers, by wind and wind drift outside
these regions. That such coastal current may induce upwelling is suggested by the
analogous behaviour of wind-induced current off Antofagasta and the Guanape Islands.
The universality of upwelling off both Chile and Peru is evidence that westerly set of
the surface layers in the ocean at large is widespread. That such westerly set inshore
must be induced by aspiration as a result of winds and oceanic drift remote from the
coastal region is inferred by reference to the conditions at Pichidanque Bay and Callao,
and from the fact that winds are stronger and more easterly in the open ocean. At these
localities upwelling could be due to no other cause since no surface current was
observable.
That the degree of upwelling showed a considerable uniformity over the whole coast
suggests that this indirect effect of distant wind may outweigh in importance the local
winds having a direct action. This may indeed be a principle operating along the length of
the west coast, and so to speak guarantees a minimal quantity of cool water close inshore
even under the most diverse local conditions. Upwelling would be greatly augmented
by local southerly wind and northerly current, but perhaps never altogether suppressed
by local contrary wind and counter-current. Thus the effect of swirls and eddies would
merely be to retard organic production in one place and to accelerate it in another.
EFFECT OF LATITUDE
Wind and current are stronger and more regular on the coasts of Peru than on the
coasts of Chile. There is, moreover, a greater difference between the densities of the
water at the surface and the water at the upwelling depth off Chile than there is off
Peru;! so that off Chile more force is presumably required to cause upwelling. Yet up-
welling is not so very much more vigorous off Peru, and it certainly does not seem
commensurate with the stronger wind, the current and more uniform density ; and there
are probably other factors whose influence have yet to be considered. One of these may
be the greater area of shallow water and greater area of the current included in the
upper depth of frictional influence in Peruvian than in Chilean waters (see p. 204).
Another factor may be the effect produced on a current by the earth’s rotation in
1 Density, together with other physical and chemical data, will be published in due course in the Discovery
Reports.
D XIII 14
212 DISCOVERY REPORTS
different latitudes. It is well known that the deflecting force is a function of latitude,
is maximal at the poles and is zero at the equator. It may be a factor of considerable
importance contributing to the uniformity of hydrological conditions on the west coast.
ERFECT OF SEICHE
The effect of seiches in oceanic hydrology has been noted in the Bay of Bengal by
Sewell (1928) and in the North Atlantic by Helland-Hansen and Nansen (1926). The
possibility that the oscillation in the temperature of the upper layers of the sea at
Callao from June 26 to August 20, might be ascribed to a temperature seiche should be
considered.! The data illustrated in Fig. 51 indicate that off Callao a peak maximum
temperature and a peak minimum temperature occurred on July 4-8 and August 4-8.
These peaks may represent respectively the trough and the crest of a subsurface oceanic
wave of cool water at the coast.
According to these dates, the seiche would have a period of about two months.
Wedderburn (1911) calculates that under certain stated conditions, a temperature seiche
in the Atlantic might have a period of 34 days. Hypothetical as this conclusion must be,
it does not seem inconsistent with the possibility admitted by our data that in the
Pacific a seiche might have a period of double this length. The period of a seiche in so
small a basin as the Bay of Bengal was observed to lie between 17 and 19 days (Sewell,
p. 168), whereas the North Atlantic seiche showed indications of being diurnal (Harvey,
1928). ‘Thus the possibilities are wide.
Unfortunately observations have not been made during other maxima and minima
before and after these dates, and they are therefore insufficient to show periodicity
which is an essential feature of the seiche. Such a seiche, if it existed in the South
Pacific, would have a decided influence upon upwelling; on the crest, subsurface water
would be closer to the surface and relatively weak forces would be able to bring cool
water and abundant nutrient salts to the surface, whereas on the trough, wind and
current of considerable magnitude would have comparatively little effect on this water.
On pp. 208-9 the rise in temperature off the Guafiape Islands on July 10 and 11 has been
attributed to change of wind: seiche is probably not operating here, because Fig. 51
shows that during this date, if a seiche were working, the temperature would be falling.
Until some knowledge has been obtained on seiche action in the Pacific, the full effects
on upwelling of the separate factors outlined in the foregoing pages cannot properly be
understood,
SPEED OF UPWELLING
No calculations have been made to indicate the rate at which water may well up, but
the apparent quick response of the temperature at and below the surface to changes of
wind supports Schott’s view that a speed of 15 m. a month as suggested by McEwen
(1929, p. 259) is far too slow. Rate of change in hydrological conditions is also con-
sidered on p. 213.
1 T am indebted to Lt.-Col. R. B. Seymour Sewell for this suggestion.
THE THEORY OF SUBSIDENCE 213
THE EVIDENCE FOR THE THEORY OF SUBSIDENCE?
It will be convenient to summarize the evidence scattered among the earlier sections
and discussed above in support of and against a theory that an onset of contrary condi-
tions may be followed by some subsidence of the upwelled water.
According to Coker (1918), fishermen have long believed in a swinging out to sea of
the current to explain the disappearance of cool water from the coast; and its occasional
disappearance is noted in sailing directions. In earlier pages (pp. 206-9), such dis-
appearance of the cool water has been supposed possible, not by a horizontal swing but
by a vertical swing within the current.
At Antofagasta and the Guanape Islands, the rise in temperature was rapid but so
also, generally speaking, were the horizontal currents which might therefore have been
the cause; at Antofagasta by a cyclonic inflow of warm water from the north, and at the
Guanape Islands by an anticyclonic outflow of cold water to the north-west.
At Antofagasta, (1) the drift of the ship against the wind and towards the shore at
St. WS 630, and (2) the rise in temperature simultaneously with a falling off of the wind
strength well before the subsequent change in its direction (Sts. WS 629-630), are to-
gether facts strongly in support of the subsidence theory (see p. 142). For the rise in
temperature between Sts. WS 629 and 630 might alone have meant nothing more than
the admixture of upwelled with oceanic water. The magnitude of the shorewards drift
at St. WS 630 at 17-26 miles from land could not easily be attributed to the coastal eddy
by which the inrush of warm water off Bahia Herradura may be explained (Figs. 9
and 28). The fact that the second line of observations lay in the region of eddy and not
over the first line weakens the value of any evidence that might be furnished by com-
parison of subsurface isotherms on these two lines. At the present stage the evidence
may be considered insufficient to decide how much of the rise in temperature on the
second line was due to subsidence and how much due to admixture with oceanic water
and the eddy. It is certainly suggestive that the three mechanisms were in operation.
At the Guafiape Islands the continuance of northerly current after change of the wind
may have been caused by aspiration from the north: and the conditions bore some re-
semblance to those at Arica, where the seemingly paradoxical co-existence of con-
vergence and divergence has been noted. The evidence is clearly insufficient to decide
the question whether some subsidence had occurred as a result of the wind change.
Three alternatives have been suggested as the possible causes of the temperature
oscillation at Callao: the action of local wind; a shift in the position of the anticyclonic
swirls, with especial reference to the point of convergence of the wedge; and the action
of seiche. The first was considered insufficient, alone, to cause the temperature changes,
while of the other two the data are inconclusive. While any horizontal current off
Callao must have been very slow (p. 129), the temperature changes also were very slow
1 The term “subsidence” here denotes a reversion of the water layers towards a condition of horizontal
stratification and should be distinguished from sinking brought about through accession of density.
14-2
214 DISCOVERY REPORTS
(see Table VII, p. 170). Subsidence between the dates June 25 and July 8 and August
7-20 remains a probability but cannot be regarded proven.
SINKING OF NEWLY MIXED WATER
Indications of this phenomenon off Caldera (p. 140) leads one to suppose that the
mixing of upwelled with oceanic water must lead frequently to the formation of heavier
water which thereupon sinks on the outer edge of the zone of uprising. Such sinking of
the product of recent mixing is, of course, to be distinguished from subsidence of
recently upwelled water. Upwelling and subsidence of the lower layers may be de-
scribed as a see-saw motion dependent upon variations of wind or of other forces re-
sponsible for the divergence of surface water from the coast: subsidence restores
equilibrium by the passive method of letting the water layers revert towards a condition
of horizontal stratification. Sinking of heavier water, on the other hand, restores equi-
librium by disrupting thermal stratification; it is irreversible in its action. Although
newly mixed water which is sinking is independent of any external force other than
gravity, it may be to a large extent dependent on wind action for its inception. Thus
at Caldera its appearance coincided with the convergence of warm offshore water with
the cool inshore water, and with local northerly wind. Whether the cool water inshore
was welling up concurrently with this convergence of the warm water, as a result of
the southerly winds recorded offshore or of winds even farther from the coast, or
whether the cool inshore water was subsiding, is not known.
Other instances of sinking of newly mixed water are probably to be found among
our sections; though most to be expected in the neighbourhood of the subtropical
convergence, it is probably a phenomenon of importance in the mixing process of the
coastal current waters. At Cape Carranza, an appearance of sinking water at St. WS
597 is also correlated with northerly wind, but cannot illustrate this phenomenon since,
south of the subtropical convergence, the water is less saline offshore than inshore.
CENTRES OF UPWELLING AND OTHER IRREGULARITIES
OF THE CURRENT
CENTRES OF UPWELLING
Schott has suggested that the length of coast between Coquimbo and Punta Parina
may be divided into four regions,! each distinguished by strong upwelling which sets in
with a sudden lowering of temperature and then dies away northwards so that finally
almost normal temperatures are found over short distances. In Schott’s graph com-
paring inshore temperatures with those at 80-100 miles offshore, the points of con-
spicuous upwelling are Antofagasta, San Juan and Punta Aguja. The points of least
upwelling are north of Coquimbo, south of Antofagasta, Arica and Puerto Chicama.
1 T have used the word “region” instead of Schott’s word “zone” because I have already used the word
zone in a different sense elsewhere.
CENTRES OF UPWELLING 215
The variations from this order in September 1927 and November 1929 are slight,
amounting principally to a state of vigorous upwelling off Puerto Chicama in 1929.
Our experience was much the same; we found very much more active upwelling off
some parts of the coast than off others, and the regions noted by Schott can be dis-
tinguished both in the curves in Fig. 66 and in the chart of surface temperatures in
Figs. 16 and 17. Thus in region I from lat. 30 to 25° S, vigorous upwelling off Caldera
lowers the mean temperatures in lat. 27—28° S as far as 10 miles offshore. ‘The second
focus of upwelling occurs off Antofagasta in region II in lat. 25-18° S. In region III
(lat. 18-8° S) the upwelling is at San Juan, but in region IV upwelling off the Lobos
Islands was not quite so vigorous. Points of exceptional warmth were found south of
Antofagasta in region I (Fig.g) and in moderation off Callao in region III, but at no
other localities close inshore. This agreement in the localities of major upwelling makes
it very likely that these centres of upwelling are more or less permanent. As a natural
consequence follow differences in the breadth of the cool zone and in the gradient
between inshore and offshore temperatures (see Figs. 29 and 30).
Particular interest attaches to these centres since they are found to correspond with
the anticyclonic swirls suggested on p. 192 and Fig. 63. The two swirls off Peru are
illustrated diagrammatically in Fig. 66 by arrows which curve away from the graphs in
the divergence regions of strong upwelling, but curve towards them in the warm con-
vergence regions. The very similar nature of the upwelling centres off Chile and their
comparative permanency makes the existence of similar swirls, though weaker and
probably less pronounced, to be expected off the Chilean coast. The probable positions
of the hypothetical swirls are also marked in the figure.
IRREGULARITIES OF THE CURRENT
No account of the current would be complete without some reference to its extra-
ordinary variability. In almost every particular, drift, temperature, breadth, colour,
etc., it is fraught with irregularity. In their persistent references to the uniformity of
the conditions on the west coast, earlier workers are apt to mislead. Thus Murphy
(1925) says: ‘‘ Extraordinary uniformity is, after all, the outstanding oceanic feature of
the Peruvian littoral.’’ And Schott (1931) writes: “‘On the large scale the temperature
too is uniform, for in the water it varies little with the latitude and according to no
obvious law, and little with the season.”’ He is accounting for the slight differences
between mean temperatures in low and high latitudes within the coastal region and
the equable climate that results: yet later (1932) he writes: “‘...therefore the quantity
of upwelling water also varies from place to place. In consequence of this situation the
surface temperature. ..are depressed in complicated and irregular variations along the
coast.” These variations are a conspicuous feature of the current and may be due very
largely to the swirls above described; we may illustrate their nature with a few selected
examples.
Changes of temperature along the coast sometimes occur abruptly within short dis-
tances, and the following record as the ship left Coquimbo Harbour on a course of 353°
216 DISCOVERY REPORTS
may be cited. It is suggested on p. 140 that this may have been the result of a recent
change of wind.
Table XX. Fluctuation of surface temperature on 3. vi. 31, On a course
of 353° from Coquimbo Harbour to 28° 47’ S, 71° 44’ W
Hae Distance from shore Surface temperature
miles (approx.) Gs
1415 2 I5"10
1500 Za 14°64.
153° 5 Maa
1600 9 13°55
1630 12 14°58
1 7feKe) at eas)
1800 14. 13°95
2000 10 15°03
5000 16 15°20
Temperatures are found to vary from one year to another in a way apparently
unrelated to seasonal changes. The anomaly between our records and those of Schott
at Arica have been noted on p. 203. In Pisco Harbour the water inshore is sometimes
warmer than offshore, sometimes cooler. In September 1927 and November 1929 the
‘Emden’ and ‘ Nitocris’ registered respectively less than 15 and 16° C., and the water
offshore was presumably warmer. But Murphy in 1919 and we ourselves in 1931 found
the reverse. He found 20-00° and 20-56° C. in October and November, and we found
1g'10° C. in June, whereas southwards of Paracas Peninsula readings were as low as
14°89° C. We have unfortunately no salinity observations with which to confirm
Murphy’s suggestion that high temperatures here may be explained by the discharge of
freshet waters from the Pisco River. If the swirls altered their position as suggested on
p. 210 these changes would be readily explained.
Changes in the distribution of surface isotherms from day to day, almost from hour
to hour, will have been noted in the paragraphs dealing with the effect of wind upon
upwelling. ‘To these examples may be added a record of the temperatures in the con-
vergence region off Capo Blanco before and after the ship’s sojourn of five days in
Talara. The changes in the probable distribution of isotherms are illustrated in Figs. 70
and 71. Such changes as these have been noted by many earlier observers and may be
regarded as a normal feature of this coast.
Lavalle (1924) has described an invasion of the coastal waters of Peru by a counter- ~
current which occurs annually between the months of April and July, and which he
supposes to originate from the Equatorial Counter-current. Its strength varies with the
year, but its convergence with the cool coastal water produces aguaje, and in 1923 drove
away the guano birds.
Lavalle publishes records of surface temperature off the Guafiape Islands and Palo-
minos Island for the months of April, May and June during the years 1921-3. From
CENTRES OF UPWELLING AND ANTICYCLONIC SWIRLS 217
—PICHIDANQUE BAY
— CAPE CARRANZA
— CALDERA
— ANTOFAGASTA
— SAN JUAN
— CALLAO
— GUANAPE I.
= /HOBOSiIs:
— PUNTA AGUJA
— CAPO BLANCO
— SANTA ELENA
RELATIVE POSITION OF ANTICYCLONIC SWIRLS — DIAGRAMMATIC
100-500 MILE ZONE
REGIONS SUGGESTED BY THE CURVES
| REGION I REGION IT | REGION IL |
REGIONS RECOGNIZED BY SCHOTT
REGION I REGION I REGION I
10° S. LAT.
Fig. 66. Centres of upwelling. The three curves illustrate the mean surface temperature of the current along
its path; they represent three zones parallel to the coast at <5 miles, 5-20 miles and 20-100 miles from it.
Above the curves, the two anticyclonic swirls off Peru are shown diagrammatically, their points of con-
vergence and divergence corresponding to the peaks and the dips in the curves. Equivalent swirls are
postulated off the Chilean coast. Below the curves, the four centres of upwelling are identified with the
regions recognized by Schott. The curves represent a combination of the data given in Appendix VI and
Fig. 34. Temperature records at greater distances than 100 miles are given as ringed dots.
218 DISCOVERY REPORTS
these data! the remarkable fact emerges that off the more southern Palominos Island
the April and May temperatures were, on the whole, higher than those off the Guafiape
Islands lying some 240 miles to the northward. Such a distribution of temperature
would not arise from a counter-current of warm water flowing from north to south
along the coast, and it is unlikely, therefore, to be due to a repetition of the Nivo current
out of season. Lavalle gives no salinity data by which the origin of this water can be
established, but the temperature data might be explained if the counter-current came
from the open ocean and was an over-developed wedge of the type met with during our
survey.
PHOSPHATE AND ORGANIC PRODUCTION
In an earlier section, an attempt has been made to correlate organic production on the
west coast with the hydrological conditions. A study of the phosphate content has shown
that the concentration of nutrient salts at the surface varies according to the extent of
the cool water in the different localities (pp. 182-3); and that the rich nutrient salts may
be identified with upwelling water is shown by comparing Figs. 54—61 with Figs. 18-50,
the corresponding sections of temperature and salinity.
The relation of nutrient salts to the plant life in the sea is best known from the work
of European investigators, and in the sub-Antarctic from results recently obtained by
the Discovery investigations (Hardy and Gunther, 1935). An examination of this re-
lationship in the Peru Coastal Current has shed interesting light not only on the
conditions met with at the time of the survey but possibly also for some considerable
time in the immediate past.
Volumetric measurement of settled phytoplankton shows that within 100 miles of the
land, catches are on average larger than beyond (Table XI); that in regions of rich
phosphate the average catch is larger than in regions of poor phosphate (Table XIII);
and that this close relation between the two is suggestive, on the strength of results of
Atkins and others, of a dependence of plankton upon phosphate.”
This dependence of the phytoplankton upon inorganic salts can be examined more
closely, only if it is possible to measure their reduction with the growth of the plankton.
Neither the methods employed by Atkins (1923), Gran (1927) or Schreiber (1927) are
available to a ship on the move, and an alternative though less accurate method has been
considered. It consists in comparing the phosphate concentrations above and below
the compensation point at each station, and it assumes that initially the phosphate con-
centrations at the surface and at 100 m. are approximately the same or within limits
bear the same relation to each other, and that subsequent changes are comparatively
1 The higher index of the maximum and minimum thermometer appears to have been misread at both
islands, but the error does not seem to affect the comparative value of the data.
» In Table XIII we see incidentally that when the zooplankton exceeds a certain concentration the phyto-
plankton is severely reduced. That the phytoplankton has been cropped down by the zooplankton which is
here in greater quantity than at any of the other localities listed, is put forward as the most likely of possible
explanations.
REGIONAL FERTILITY 219
small in the lower layer. The mean values of the phosphate concentrations at o and 20 m.
on the one hand and 80 and 100 m. on the other have been chosen as representative of
these two levels. The method appears to be applicable to an area such as this in which
the surface waters close inshore are replenished by upwelling of nutrient salts in a zone
where vertical mixing is extensive within 100 m. of the surface, and in which these
waters drift away from the coast and acquire thermal stratification as they enter upon
oceanic conditions. It is not applicable, however, to counter-currents introduced into
the upwelling area from the open ocean.
Phosphate data have been studied by this method at three localities, at Cape Carranza,
Antofagasta and San Juan, but elsewhere the catches of phytoplankton were small and
our preliminary measurements unrepresentative. In Tables XIV and XV the percentage
figures expressing depletion for stations of different phytoplankton concentration have
been averaged. The curve in Fig. 62 shows that depletion increases with the phyto-
plankton concentration, and the fact that five points out of seven lie on a straight line
suggests a direct relation between the two. The relatively big depletion (21 per cent) of
phosphate corresponding to the thirteen stations where the volume of phytoplankton
averaged less than 25 c.c., would be explained if phytoplankton at these stations had
been grazed heavily by herbivorous zooplankton; it is not wished, however, to stress
the accuracy of this curve whose straightforwardness was unexpected.
Conditions on the west coast are thus seen to fall into a series, grading from localities
of minimal cool water, nutrient salts and plankton, to localities of active upwelling,
rich nutrient salts and rich plankton. At Pichidanque Bay, Arica and Callao in July
the weather had been calm for a considerable time and the surface layers were re-
latively impoverished of phytoplankton; at the first phosphate was negligible, at the
others it was not estimated. At Caldera such a period of calm had recently been broken
by southerly winds and upwelling, with the result that phosphate at the surface had
reached medium values but phytoplankton had not had time to develop far. At Anto-
fagasta where upwelling seemed to have been in progress for longer, the largest catches
were taken at 7-15 miles from the coast, and the most recently upwelled water lying
inshore had a small diatom content. At Cape Carranza, San Juan and the lines off
northern Peru, wherever phosphate was examined it was rich, and heavy catches of
plankton were taken at all of them. Considering the movement in the current the
accommodation of the plankton to the hydrological conditions is remarkable.
The uniformity claimed for this area by many writers might lead to the supposition
that it is uniformly fertile over its entire length. ‘The differences in the abundance of
phytoplankton, noted above in the separate localities, would be attributable to tem-
porary changes in hydrological conditions. In support of this view is the fact that up-
welling was marked in all the localities and that they are therefore all productive. The
majority of evidence is, however, against this view. The apparent permanency of the
centres of major upwelling, together with the other facts from which the existence of
large anticyclonic swirls has been inferred, and lastly the adjustment of the phyto-
plankton to the recognized upwelling centres, go to show that certain localities are
D XIII 15
220 DISCOVERY REPORTS
perennially more fertile than others. In this event, the poverty of phytoplankton at such
localities as Callao, Arica and Pichidanque Bay may be interpreted, not only as an
indication of conditions in the immediate past, but also perhaps as evidence of the
inflow of barren oceanic water in regions of convergence.
If vertical currents are important as a source of production, horizontal currents may
be no less important in collecting plankton together in patches and thus in providing
the larger animals with a feeding ground. With reference to the vertical migration of
plankton animals, Hardy (1935) has shown the possibilities in navigation open to an
organism migrating regularly between two currents. By this mechanism he has shown
how animals might be collected together in patches, disperse and perhaps migrate
towards food or away from an uncongenial environment.
Fig. 67. Hypothetical diagram of a surface eddy. (After Hardy.)
In this connection the collection of animals in the eddy off the Lobos Islands becomes
of great interest. Hardy gives two hypothetical cases of currents which would collect
organisms together without their having to alter their migrational rhythm. The first is
of an eddy situated over another current. We are indebted to him for permission to
reproduce his illustration in Fig. 67; the lower current is represented by fine broken
lines and the paths of two hypothetically migrating organisms A and B which are carried
to the positions A’ and B’ are shown by heavy lines. Inside the Lobos Islands, a
surface layer of warm saline water is strongly suggestive of an eddy lying above the
main current: and here the collection of thick zooplankton, of anchovy, bonito, birds,
seals and whales, is probably to be identified in principle with the theoretical con-
siderations Hardy has sketched.
CAUSES OF DISCOLORATION 221
Although a similar effect might not be expected in the larger anticyclonic swirls, the
high temperature of the warm wedge checking perhaps the range of vertical migration,
yet an eddy of this type seems to have interesting consequences on the plankton (see
pp. 229-33). Attention might also be drawn to the identical observations made by Ulloa
(Juan and Ulloa, 1748) and Smith (1899), of a patch of green water off the Island of
Santa Maria in southern Chile, but in the absence of further data, this is a coincidence
which must remain a matter of record.
COLOUR OF THE CURRENT
The various colours of the water described on pp. 173-5 and illustrated in Plate XVI,
at first seeming to lack orderly arrangement may be grouped into three classes:
1. The three basal colour types, to one or other of which all oceanic water may be
referred. As shown by Buchanan these are either blue, indigo or green. They have
transparency.
2. Opaque colours occurring near land and at other centres of exceptional phyto-
plankton production such as in the polar regions. They are presumably referable to
animal or terrigenous origins; they are usually reddish, muddy or chalky, and often
occur in patches of a few hundred yards or a few miles in extent. Intermediate browns,
ochres, khaki, etc., might be produced either as the result of abnormal conditions (see
below) or by admixture of 1 and 2.
3. Colours of holophytic organisms such as Trichodesmium, colonial Radiolaria and
flagellates. ‘They are straw-coloured, orange or red, and they, apparently, may occur at
any distance from land: these also occur in swarms.
The normal colour distribution in the eastern South Pacific may be said to consist of
a coastal zone of green modified locally by varying concentrations of the colours of
classes 2 and 3, and this is flanked in the open ocean by indigo in the temperate and
ultramarine in the tropical regions. Indigo and blue being basal colour types in these
latitudes, are not understood as being colours peculiar to the Peru Coastal Current.
While the green colour of the current is evidently attributable to phytoplankton, and
while aberrant colours when due to the swarming of holophytic organisms can usually
be identified by the predominance of a particular species, so far our knowledge of the
nature of the colours of class 2 comes mainly from indirect evidence.
Near Callao, for example, no specific organism seemed to be associated particularly
with the rusty coloured patch; and zooplankton was no more abundant here, at the
Guanape Islands, or at Pisco, where the more unusual discolorations were met with
(Plate XVI, figs. 6, 7 and 11), than at other localities where the water was green.
Moreover, the great majority of zooplanktonic organisms not only in temperate, but in
polar regions, are known to make diurnal migrations, seeking the less illumined layers
during the hours of daylight (Russell, 1927, 1928, 1931; Hardy and Gunther, 1935).
It is improbable therefore that in normal conditions the colour of the sea surface is much
affected by the animal constituents of the plankton. The brick red swarm of euphausian
15-2
222 DISCOVERY REPORTS
cyrtopias was the only example met with, and the parallel to the peculiar behaviour of
Euphausia superba in the Antarctic has already been referred to. It may be noted that
where there is evidence of swarming animals in earlier records, the colour is usually
described as reddish (Funnel, 1729; Fitz-Roy, 1839; Rayner, 1935). he unusual dis-
colorations have some resemblance to the colours that have been described as charac-
teristic of aguaje (Raimondi, 1892; Stiglich, 1925). Further reasons for associating them
with this phenomenon are given on pp. 229-33, where it is shown to be abnormal.
A point of interest is that the green colour and the colours of class 2, if produced
by plankton, are practically confined to within 30 miles of the coast; whereas the
zooplankton seems to be no less abundant at distances of 100 and 200 miles and the
phytoplankton reaches its greatest mean volume at 80 miles offshore. It does not seem
as though the areas of most intensive organic production can be identified with the
coloured water, although the latter coincides with the coolest temperature and the
richest phosphate. In searching for another explanation, it should be remembered that
the cool inshore temperatures result in a cloud formation which hangs over the littoral
as a narrow canopy over most of its length. It seems probable that conditions beneath
this cloud are such that the phytoplankton finds its optimum illumination at the very
surface close inshore, whereas in the open ocean where the light is more intense,
diatoms may sink and scatter at lower levels and the green colour thereby lost. Dr T. J.
Hart, with whom I have discussed these questions, has suggested that systrophe on the
part of diatoms in the well-illuminated zone might lead to a similar contrast between the
blue colour of this water and the green in the zone where cloud allows full expansion
of the chromatophores (Marshall and Orr, 1928). The zooplankton, though reacting
differently to light, might occupy a higher level in the coastal zone, and in this way fish
would also come closer to the surface inshore than offshore, and this might account for
the restriction of the birds and seals to the very narrowest zone. This would be brought
about equally if the fish favoured littoral rather than oceanic species of the plankton.1
BOUNDARIES OF THE PERU COASTAL ‘CURRENG
Though sharing in the general anticyclonic circulation, the coastal region and the
open ocean of the eastern South Pacific have been seen to show profound hydrological
differences. In the open ocean the South-East Trade is normally developed, whereas
on the Chilean coast the wind weakens and has a meridianal direction. In the open ocean
the northerly surface drift has a large westerly component, whereas close inshore the
drift is parallel to the coast. These currents, acting in conjunction with the earth’s
rotation, produce a divergence of surface water from the coast whereby the lower
layers are induced to well up in compensation. Contrasted with these inshore vertical
1 Any modification of coastal colour that might be due to the distribution of zooplankton would be
explained if the littoral species were more opaque than the oceanic. It is well known how well adapted to
their environment are the pelagic organisms of tropical seas, being either transparent or blue or having
silvery scales capable of almost perfect reflection.
COASTAL AND OCEANIC CURRENT 223
currents the surface layers of the open ocean are cut off sharply from those below by
a well-defined discontinuity layer which checks vertical mixing. Above the dis-
continuity layer a depletion of nutrient salts brought about by the phytoplankton is
followed further west by a decrease of the latter and of the zooplankton: in this en-
vironment, species are oceanic. Near the coast, on the other hand, where upwelling
provides a constant supply of nutrient salts at the surface, a dense growth of phyto-
plankton is possible, and this leads to a wealthy plankton fauna and to immense numbers
of animals of economic importance. The species here are littoral. ''emperature and
salinity of the surface inshore and offshore are to some extent symptomatic of these
changes.
Beneath the surface, a northerly current of sub-Antarctic origin, and a southerly warm
highly saline return current wedged between sub-Antarctic water and the Antarctic
intermediate water, appear to be features characteristic of the coastal water. They
appear to be drawn towards the upwelling region in compensation for the upwelling
water and thus may not feature in the open ocean.
Thus in the upper 400 m., biological, chemical, and physical characteristics, both of
the surface and of the deeper layers, distinguish the inshore from the offshore waters.
Meteorological differences also exist, and among them the condensation of cloud over
the cool upwelling zone should be mentioned. As a result of this lessened illumination,
phytoplankton probably comes close to the surface inshore, but in the open ocean
either affects systrophe or sinks deeper, with the consequence that inshore waters are
normally coloured green, whereas waters of the open ocean are ultramarine.
In view of the desirability of keeping the distinct identity of the two regions in mind,
the oceanic drift will be distinguished from the coastal current by the name Peru
Oceanic Current. The Peru Coastal Current will be kept for the system of inshore cur-
rents with which the name Humboldt Current has often been associated. The name
Peru Oceanic Current will be kept exclusively for the waters offshore, different in
composition but sharing, to some extent, the northerly movement of the anticyclonic
circulation.
Salinity in the upwelling region is lower than values offshore north of the subtropical
convergence, but higher inshore than offshore south of the convergence (pp. 159-62).
On account of this reversal north and south, and because salinity at the surface is liable
to be altered by precipitation and evaporation, temperature is perhaps a better guide to
the boundary of the Coastal Current.
WESTERN BOUNDARY
The effect of upwelling upon the surface isotherms is shown in Figs. 16-17 and
29-30, where it is seen that the water inshore is some 2—5° cooler than the outermost
of the observations on the same parallel, with the consequence that isotherms run in
the same direction as the coast but converge with it slightly towards the lower latitudes.
The normal oceanic trend of isotherms in an east and west direction, reflecting the
increase of surface temperature with decrease of latitude which occurs over the major
224 DISCOVERY REPORTS
part of the ocean, is here subordinated to the overwhelming effect of local cooling.
It is to be noted that this trend of the isotherms parallel to the coast holds over the
entire region surveyed by the ‘William Scoresby’. This means that the controlling
influence of the upwelled water covers an area extending into the ocean at least as far as
50-130 miles off Chile and 150-250 miles off Peru (Figs. 16 and 17). The length of any
line was terminated when the isotherms beneath the surface showed an almost horizontal
tendency. This was necessary on grounds of economy, but it cannot be regarded as
the limit of influence of the upwelling water, because our figure shows that surface
isotherms still run parallel to the coast. Moreover, the presence of a series of anti-
cyclonic eddies offshore, shows that coastal disturbances extend much farther. The
limit of influence is evidently outside the area investigated by the ‘ William Scoresby’.
Schott and Schu’s diagrams illustrating the mean annual disposition of surface iso-
therms in the Pacific lends support to this conception (Fig. 68). The isotherms run east
and west over the majority of the ocean, but on approach to the South American continent
they curve northwards until they run in a direction similar to those in Figs. 16 and 17.
The isotherms show the effect of the coastal influence at very much greater distances off
Peru than off Chile. Thus off southern Chile the isotherm of 13° C. shows distinct
northerly displacement in 40° S at a distance of about 300 miles off land (say in 80° W);
whereas off Peru the isotherm of 26° C. becomes displaced in 15° S at a distance of
3600-4000 miles off the coast, that is in mid-Pacific. Thus there is a gigantic wedge-
shaped area of ocean with its apex in the south and its base almost over the Equator, and
the temperatures over the whole of this area have the appearance of being depressed by
upwelled water off the coast, Fig. 68. In this cooling below the mean temperature of
waters in the eastern South Pacific it must not be overlooked, as pointed out by
Sverdrup (1931), that water is being carried northwards from cooler latitudes (see
pp. 195-6).
Although the influence of upwelled water may be carried westwards for great dis-
tances, and in the path of the South Equatorial Current indefinitely, the area which with
advantage can be looked upon as the Peru Coastal Current proper must be very much
smaller.
Owing to the variability of the Peru Coastal Current, no exact boundary can be placed
between it and the Peru Oceanic Current. Not only are the zones occupied by
marked northerly current, upwelling, rich nutrient salts, guano birds, coloured water,
rich phytoplankton, rich zooplankton, cool water, etc., all of different breadths, but they
are ever variable. Thus the temperature charts published by the Deutsche Seewarte
show considerable variations in the position of isotherms from one season to another.
Moreover, as a result of its deflection the water drifts across the westward boundary
from the Coastal Current to the Oceanic Current.
The agreed actual position of the western boundary will therefore be arbitrary. If
temperature is accepted as the criterion, one might be guided by the trend of the mean
annual isotherms. It is where they change direction and run north-east and south-
west that the western boundary of the Coastal Current might be placed. Using the chart
BREADTH OF THE PERU COASTAL CURRENT 225
———
Fig. 68. The limits of the Peru Coastal Current based on the distribution of mean annual isotherms as given
by Schott and Schu.
prepared by Schott and Schu (1910), the boundary might be placed in the following
localities.
Table XXI. Supposed western boundary of the Peru Coastal Current
“cae pea Miles from the coast
fo) Peru Coastal Current extends westwards as South Equatorial Current
10 95-115 1000
20 85-— 90 goo
30 75 180
40 South American coast fe)
226 ; DISCOVERY REPORTS
SOUTHERN BOUNDARY
Authors of text-books usually look to the West Wind Drift for the origin of the Peru
Current (Hoffmann, 1884; Somerville, 1923). The West Wind Drift is described as
dividing into two branches at its point of impingement (usually given as 40° S) against
the South American continent: the Cape Horn Current flowing to the south, the Peru
or Humboldt Current to the north.
It is probably true that the greater part of the sub-Antarctic water which turns north-
ward is derived from the West Wind Drift. Such water may be considered as belonging
to the Peru Current in the wider sense, and particularly to the Peru Oceanic Current.
It remains oceanic until it has mixed with upwelled water. For the southern boundary
of the Peru Coastal Current therefore, we should look for the most southern upwelling
centre. ‘he southernmost limit has been variously set by different writers at Cobia
(Vallaux, 1930), Copiapo (Deutsche Seewarte), the region between Antofagasta and
Coquimbo (Schott) and Valparaiso (Hoffmann, 1884). Schott records that upwelling
began somewhat north of Coquimbo in about 29° S in September 1927. He points out
that this satisfies the theory of a correspondence between depression of the temperature
of the coastal waters and a low rainfall on the adjacent land. Incidentally it is close to
where the subtropical convergence approaches the coast: i.e. where upwelled water
becomes less saline than the open ocean. Coquimbo has a rainfall of about 100 mm.
whereas Taltal in lat. 25-5° has about 15 mm. and comes definitely within the upwelling
region. While Schott makes this point in his account of the Peru Current, it is to
be noted that according to the chart published by Schott and Schu (1910) surface iso-
therms of the Pacific curve northwards near the coast in lat. 40° S. Since any northerly
drift of the surface water is likely to entail some upwelling the temperature at the
commencement of the Peru Coastal Current is liable to be lower than at the commence-
ment of the Cape Horn Current, as was observed by Perez-Rosales (1857).1
Our own observations show that upwelling may occur at least as far south as Cape
Carranza and with strength off Copiapo. Upwelling is no doubt liable to occur at any
point off the coast where northerly drift happens. Mossman (1909) has shown with
some precision that the dividing line between the meteorological cyclonic and anti-
cyclonic circulations normally lies at about 41° S. South of this the prevailing wind is
west-north-west in all seasons, whereas northwards the prevailing wind alternates with
season. From October to March it is southerly; from April to September northerly ; it
brings the monsoon to the Chilean littoral, and may be felt as far north as Caldera.
Hoffmann (1884) states that between Valparaiso and the 4oth parallel, a northerly gale
in winter is always followed by a strong southward current. Gunckel (1928) states that
1 According to Murphy (1923) “the current laves the western coast of South America from a point some-
where south of 40°”. But he also says: “‘It is in accord with the abyssal topography that the current as
characterized by upwelling waters, should begin near Valparaiso, for just south of that port the great bank on
which Juan Fernandez lies extends to the westward more than twenty degrees of longitude.” We have shown
on p. 205 that the Juan Fernandez Rise has no appreciable connection with the surface waters.
SOUTHERN LIMITS OF THE PERU COASTAL CURRENT 227
STATION NUMBERS __WS/726 Ws7es WS724 ws723 wS72e ws7el Ws720 ws7lg
LATITUDE 7S | 7 ; :
20 Vl
sili 20"
DEPTH IN METRES
‘ (0°
se ; Ee . ea PRES dl
OFF PUNTA AGUJA OFF CAPO BLANCO OFF SANTA ELENA
204 MILES 10 MILES ‘ 54 MILES
Fig. 69. Distribution of temperature (° C.). Section of the current as it leaves the Peruvian coast on its way to the Gala-
pagos Islands, August 1-4. The position of this section is shown in Fig. 2; the corresponding salinity section, in Fig. 49.
plants indigenous to regions north of the Rio Bio-Bio have been washed up at Corral,
and that this has been accepted as evidence of a southerly flowing current.
Reference to the seasonal data given in Table IX (p. 172) shows that during winter
the surface temperatures on the west coast had experienced a decline everywhere except
in the latitudes 34-39° S, but that here from May to September the temperature had
risen. As this is within the monsoon area, we may infer this rise to have followed an
alteration in the direction of surface drift. No widespread northerly drift on this coast
has been found unattended by upwelling and the May temperatures may still have borne
the impress of the cooling effects of the southerly winds of summer: but with the arrival,
during the winter months, of the monsoon from the north, the surface drift probably
became southerly and upwelling automatically came to a stop; the surface temperature
rose, and this has shown itself in spite of the advance of winter.
According to these observations, the southern limit of the northerly current varies
with season, and with it the upwelling characteristic of the Peru Coastal Current.
According to Table IX, the surface temperature south of 40° S shows no seasonal
anomaly, and this water may be regarded as belonging to the Cape Horn Current. The
extreme southern limit of the Peru Coastal Current may therefore be placed at 40—-41°S,
which falls within a degree of Mossman’s meteorological division.
DXIII
228 DISCOVERY REPORTS
NORTHERN BOUNDARY
From the wedge-shaped area of cool water over the tract extending westwards from
the Piura coast towards the Equator where the Peru Coastal Current is on its way to
the South Equatorial Current, Schott (1931) deduces a divergence line along which
upwelling occurs far out to sea. Water north of the line remains in the South Equatorial
Current, water deflected to the south mixes with the warmer South Pacific.
This interpretation may explain the data recorded in Fig. 16, which are themselves too
few to illustrate the conditions described by Schott. The bulge in the isotherms off
northern Peru may represent the base of a wedge of cool water extending westwards, and
it is possible that some of the water in this area has come to the surface along a di-
vergence line extending west-north-west into the open sea. The results obtained on a
line of stations cutting across this region in a north-east by north and south-west by
south direction do not, however, support this (Figs. 49 and 69). At the northern end,
at 54 miles off Santa Elena, the hot poorly saline Equatorial Counter-current overlays
water which is essentially similar to subtropical water in the Peru Current. Most of the
surface water over the rest of the section is cool water of 19° C. and less: the warm-
water wedge is entered between lat. 5° S and lat. 7° S, and here temperature is higher.
than 20° C. The isotherm of 18° C. maintains a more or less constant depth between
40 and 50m. If the cooler water in the middle of the section was welling up to the
surface, it is natural to expect the water at 40 m. to be involved, and the isotherms of
18 and 17° C. would betray upward movement in this region, and since this does not
occur it may be doubted if upwelling is in progress except close to the shore. Conditions
may be different farther to the west where divergence may be more active.
The northern boundary of the Peru Coastal Current during the present survey as
shown by the S-shaped line of convergence between it and the Equatorial Counter-
current is noted in Figs. 70 and 71. Like the southern boundary, this is liable to vary
(Schott, 1931).
ABNORMAL CONDITIONS 229
COMPARISON OF NORMAL AND ABNORMAL CONDITIONS
ON THE WEST COAST
CLIMATE
On earlier pages, the normal wind on the west coast has been shown to be the south-
east trade, modified locally as a south wind, or as a sea-breeze, the virazon. These winds
reach a fairly high degree of saturation (80 per cent), yet as they originate from a high-
pressure centre, and blow from higher to lower latitude, they are essentially drying
winds; and as they enter the upwelling zone, condensation seldom amounts to more
than the production of garua or of coastal cloud. Where the moisture capacity is in-
creased by the higher inland temperature, and possibly also by admixture with drier
inland air, the coastal cloud vanishes and the desert character of the west coast is pre-
served (Bowman, 1916). The persistence for thousands of years of Chilean saltpetre
deposits is often cited as proof of the extreme aridity of the coastal deserts. The
contrast noted by Darwin (p. 10g) between this and other climatic regions of South
America is illustrated in Plate XIV.
Meteorological conditions reach their greatest abnormality after the summer solstice,
when, as pointed out on p. 205, the north-east trades enter the southern hemisphere and
approach the Peruvian coast as a north-west monsoon. In exceptional years these bring
torrential rains. On this coast rain is so seldom seen that the majority of houses, the
Lima cathedral included, are built of mud; and since rivers are few and there is little
vegetation to hold the soil together, rains are unusually destructive.
EL NINO
The Nifo counter-current is shown by Schott (1931) to be a consequence of the
northerly winds. References to it are made on pp. 158 and 205, and we shall do no more
here than summarize its effects in abnormal years. In place of the cool Peru Current
diverging from the shore, hot poorly saline water of the Equatorial Counter-current
flows southwards and converges with it. The rise in temperature kills fish and plankton
which then decompose and emit sulphuretted hydrogen on an enormous scale. This is
the ‘‘ Callao Painter” and it blackens the paintwork of ships lying in harbour (Raimondi,
1891), and on one occasion Chilean troops of occupation are said to have been called out
to inter miles of putrifying organisms on the beach. At the same time and no less serious,
the guano birds lose their food. Many die of disease and starvation, and others fly south-
wards in search of food, forsaking their nests and leaving the young to perish. ‘This loss
to the guano industry is said to run into thousands of pounds. In abnormal years, E/
Nino may reach as far south as Pisco, and the months of January to March are usually
given for its occurrence.
AGUAJE
Under “Irregularities of the Current”’, p. 216, attention has been drawn to observa-
tions made by Lavalle (1924) on a warm counter-current which appears off the Peruvian
coast from April to July, well after the retreat of EJ Nino. In its effects, it bears close
16-2
230 ; DISCOVERY REPORTS
resemblance to E/] Nino, since contact of its warmer water with the cool coastal water
may kill fish and plankton, and may even result in the emigration of guano birds. Such
changes in the surface water are known locally by the name of aguaje and are usually
Fig. 70. Capo Blanco. Track of R.R.S. ‘William Scoresby’, July 24-26. From St. WS 709 to 714 course maintained 270°.
accompanied by changes of colour and by liberation of hydrogen sulphide. Thus the
name aguaje has been used synonymously with el Pintor.
Stiglich (1925) gives a detailed account of the various kinds of aguaje known, with
especial reference to their colour and to the circumstances in which they occur. In this
description, much of which is gleaned from fishermen’s lore, Stiglich notes that
ABNORMAL CONDITIONS 231
‘coloured aguaje’’—as apart from the normal blue and green of the current—is usually
red or yellow and is associated with warm water. Water which is the most coloured is
said to show most movement; it sometimes attains great intensity and each time it
ECUADOR
= — — —
Fig. 71. Santa Elena and the Gulf of Guayaquil. Track of the ship, July 30—August 2. From St. WS 715 to 719 course maintained 270°.
reaches the beach, becomes redder, forming eddies by the shore. The fish, and especially
corvina, collect in these eddies. When aguaje draws off, the fish remain stupefied near the
beach and with them all other fish with their food—shrimps, octopuses, other molluscs,
sea urchins, and various other animals. Red aguaje may go away leaving the water
frothy. Fishermen say that fish washed up on the beach are poisonous and produce a
232 ? DISCOVERY REPORTS
variety of complaints varying from headache, stomachache, dreams, and seasickness to
feeblemindedness.
These observations are sufficient to suggest that the more unusual of the colours met
with by us, namely, the bright salmon at Pisco Harbour, the rusty brown south of
Callao, and perhaps the khaki near the Guanape Islands, may all be associated with this
phenomenon (Plate XVI, figs. 6, 7 and 11). In particular, our observation of rusty
brown foam (p. 174) corresponds closely to the remark made above that red aguaje may
go away leaving the water frothy. The three observations of abnormally discoloured
water met with by us were in contiguous localities: at Pisco the water had a temperature
of 19:10° C., and at Callao and at the Guanape Islands the warm wedge was converging
with the coast (pp. 192 and 209). Moreover, reasons are given on pp. 216-18 for con-
sidering that the counter-current causing aguaje, described by Lavalle, is identifiable in
principle with the northern of the two wedges of the present survey. Our failure to
notice unpleasant smell and dead fish might not be significant if we were late upon the
scene, or if the aguaje were slight.
Our observation that the orange-coloured water at Pisco contained quantities of a
flagellate with red pigment (p. 173), together with the stimulating papers of Hornell
(1917) and Hart (1934), provide much food for speculating on the causes of the aguaje
phenomenon. The parallelism between the phenomena of Karanir, Sennir and Kedunir
on the Malabar coast and of aguaje on the Peruvian coast may be shown by the following
extracts from Hornell’s paper:
...all Malabar fishermen whom I have questioned agree in saying that every year after the passing
of the rainy season and the subsidence of the south-west monsoon, if there be a continuance of fine
weather for a week or ten days, with plenty of sunshine, and a weak coastal current, the water
inshore becomes turbid and discoloured, brownish or reddish in tint; that this water has such
poisonous effects upon fish that large numbers become affected and eventually die. The first effect of
the poison is to make the fish sluggish and at this stage, as I have myself seen, boys and men crowd
to the shore and make great hauis of the dying fish. Fishermen further state that if favourable con-
ditions continue, the colour of this foul water changes and becomes distinctly redder, and emits a
stench so strong as to be almost unbearable; when this occurs they state that the poisonous influence
increases and fishes of kinds not affected during the first onset of the poison, die and are cast ashore.
They agree fairly generally in stating that sardines are seldom affected in any quantity, but some men
have told me that on two or three occasions, separated by long intervals, they have seen widespread
sardine mortality from this cause; in these cases the sea was covered for miles with dead and dying
sardines in enormous multitudes.
Hornell notes instances of water discoloured by other organisms, but concludes that
in almost all cases of widespread fish mortality the discoloration was due to a swarming
of euglenids to the virtual exclusion of all other organisms. He notes that bottom-living
fish and invertebrates are also cast ashore; and he also notes that many of the patches
of putrefying sardines were reduced to mere frothy ochreous yellow bacterial scums.
Similar instances of widespread fish mortality with discoloured water have been re-
ported from Japan (Nishikawa, 1901) and South Africa (Gilchrist, 1914), though in
neither were the organisms producing discoloration identified with certainty. In
ABNORMAL CONDITIONS 233
Saldanha Bay (South Africa) the conditions had been preceded by a spell of north-west
wind which may be presumed to have driven warm water against the coast. In Japan
and India, fine calm weather with plenty of sunshine was the rule.
Warm surface temperatures, then, seem an essential in the production of discoloured
water and fish mortality, though the activity of the surface currents mentioned by
Stiglich, if this is accurate, does not tally exactly with the quiet conditions described by
the others. In the writer’s experience, discoloration was found where the water was in-
clined to be sluggish, at Pisco, Callao and the Guanape Islands, but it was not found at
Arica where a strong inshore current prevented stagnancy. Whether the larger animals
are killed by oxygen want which might arise in a variety of ways in such densely in-
habited waters as the Peru Current, or whether from direct contact with the swarming
nannoplankton, has not been determined.
Hart’s observation that the ciliate Mesodinium swarms and discolours water under
calm conditions is very similar to the above; and that it seems to be cosmopolitan
(Paulsen, 1934; Clemens, 1935) opens the possibility that this organism too may be a
member of the Peru Current plankton. Although it has not been shown a cause of fish
mortality, its swarming if not producing a red, might when scattered produce a khaki
colour similar to that figured in Plate XVI, fig. 11. As it disintegrates in bright light
and in formalin, it would have escaped record in our catches.
The conclusion may be drawn that the phenomenon of aguaje occurs in either normal
or abnormal meteorological or hydrological conditions. When brought about by E/ Nino,
it is obviously contributing to the abnormal conditions then extant. At other times of
the year, it is probably induced in normal meteorological conditions as a result of the
convergence of a warm wedge with the coast. Aguaje, further, appears to show every
degree of intensity: from slight discoloration with relatively little destruction of marine
life, to the extremes produced during a severe invasion of E/ Nifo.
Whereas in normal conditions aguaje may be traced to the convergence of an oceanic
counter-current with the coast, the causes underlying this convergence are obscure.
The importance of the anticyclonic swirls cannot be doubted: at the same time, the
prominence of the virazon not only at Pisco, but at Callao and the Guanape Islands, may
be significant (cf. Fig. 63 with Figs. 4 and 35 and Appendix IV, pp. 259-60).
MORTALITY OF SQUIDS ON THE CHILEAN COAST
We may consider whether the annual stranding of Doszdicus gigas in enormous num-
bers on the Chilean coast can be ascribed to the above phenomena. D’Orbigny (1835-
43) writes of it as follows:
Nous avons vu la mer couverte de débris d’Ommastréphes, surtout aux mois de Février et de Mars,
en approchant des cétes du Chili par 33 degrés de latitude sud; et, 4 la méme Epoque, nous en avons
vu jetés en grand nombre, encore vivans, a la cote de Valparaiso, sur toute celle du Chili, de la Bolivia
et du Perou, 4 Cobija, au 23¢ degré de latitude sud, puis au port d’Arica. La ily en avait tant, que la
police s’était vue forcée, dans l’intérét sanitaire du pays, ordinairement insalubre, de faire recueillir
les cadavres de ces animaux, dont la putréfaction pouvait rendre l’air plus malsain encore.
234 DISCOVERY REPORTS
Whereas February to April corresponds closely with the season of E/ Nino, this
counter-current has never been recorded south of Pisco: the squids on the other hand
do not appear to be stranded north of Arica.
According to Wilhelm (1930) the squids enter the harbour alive and vigorous, and he
tells of a coasting steamer which meeting with a shoal in the open sea was unable to head
it off from Talcahuano Bay. His observations suggest that the animals are killed as a
result of battering against rocks and the quayside. The ovaries were spent, but since
the females are accompanied by males, immature individuals, and sometimes by hake
(Merluccius gayi), Wilhelm draws the tentative conclusion that the squids may have come
inshore to feed.
The squids had been in Talcahuano a week or two and were already advanced in de-
composition when our ship arrived. At that date, the plankton in the bay showed no
signs of having been killed and water was not discoloured: We are therefore in agree-
ment with Wilhelm, that on the evidence at present available this migration is more
likely to have a biological than a hydrological cause.
COMPARISON OF CONDITIONS ON THE
EAST AND WEST COASTS
The further significance of conditions in the Peru Coastal Current may be
appreciated by comparing the west and east coasts of South America. Marine life on the
Patagonian continental shelf is relatively poorer. The area is bathed by the Falkland
Current which flows past the Falkland Islands northwards towards the South American
coast, in compensation, it is believed, for the Brazil Current, as the latter is deflected
eastwards. The Falkland Current thus converges with the coast, and although con-
siderable vertical mixing takes place over the Patagonian shelf, the circulation may be
expected to share some of the characteristics of a closed system.
On the west coast, on the other hand, the Peru Coastal Current is essentially a single-
sided divergence line, and waters of different character, on the one hand from the deep,
on the other from the surface, are being constantly mixed together, drawn off, and their
place taken by fresh supplies. That areas of mixture are frequently of especial fertility
for the production of plankton has been emphasized by Hardy (1935) with reference to
the rich plankton found off South Georgia, where the waters of Weddell Sea and Bel-
lingshausen Sea origin mix.
The importance of mixture may be seen in the Labrador Current. It compensates
for the Gulf Stream as the latter deflects eastward, and it has in consequence been
regarded as the analogue of the Falkland Current. ‘The Labrador Current also converges
with the coast, yet the fisheries of the Newfoundland Banks are the symbol of very
fertile conditions. This finds a ready explanation when it is remembered that the
Labrador Current is not homologous with the Falkland Current. The Labrador
Current, having an Arctic origin, shares the fertility of polar seas, whereas the Falkland
Current is not Antarctic but sub-Antarctic, is an arm of the West Wind Drift and has
not experienced the vertical mixing of ice-laden water.
SUMMARY 235
SUMMARY
The Royal Research Ship ‘William Scoresby’ visited the west coast in the southern
winter of 1931, the object of her enquiry being the Peru Coastal Current. Observations
on temperature, salinity, oxygen and phosphate from surface to bottom, and collections
of phyto- and zooplankton in the upper layers were undertaken as a routine.
DEVIATION OF COASTAL WINDS
Wind observations are analysed and compared with earlier records (pp. 121-4
and Fig. 4). North of 40° S, coastal winds blow parallel to the shore, showing a devia-
tion from the south-east direction typical of this sector of the South Pacific anticyclonic
high-pressure area. The importance of the Andean barrier is stressed. Some evidence
was found of the onshore breeze, known locally as the virazon, another coastal modi-
fication of importance. Results show that the survey was undertaken in meteorological
conditions which may be regarded as normal.
NORTHERLY CURRENT
Though irregular in its distribution, surface current was found to have a more
northerly course close to the coast than in the open sea (pp. 133, 189 and 190). Like-
wise the subtropical convergence was found to curve northward as it approached the
coast (see below).
WESTERLY SET
Farther from the coast, northerly drift lessened but only in places was westerly set
found to be pronounced (p. 190, Fig. 14). Westerly set is inferred to be widespread in
the ocean at large by an unfailing appearance of upwelling near the coast, even under
very diverse meteorological and hydrological conditions.
VERTICAL CURRENTS
Local influences
An attempt is made to relate these diverse conditions to the volume of upwelling
which was also found to vary. The effect of local influences is considered, and the onset
of heavy wind from the appropriate quarter is shown to be responsible for an unusual
lowering of inshore temperatures (pp. 140, 143, 148-56, 169).
Subsidence
Instances of a reversal of such wind and a rise in temperature have led to subsidence.
Examples at Antofagasta, Callao and the Guaiiape Islands are given on pp. 143-5, and
153-6; while other examples may be found on pp. 169-71. Evidence for the theory is
examined critically (p. 213). Such subsidence is not supposed peculiar to the hydrology
of this coast, but may be a principle of wide application.
D XIII 17
236 : DISCOVERY REPORTS
Seiche action
The question of distinguishing between upwelling and subsidence on the one hand,
and seiche action on the other, is considered. Definite evidence of the existence of
seiches in the Pacific has not been found, but the possibility that our results may lend
themselves to this interpretation is pointed out (p. 212).
Latitude
No disparity of upwelling was noted between the Chilean and Peruvian coasts, although
the surface layers are more homogeneous, and the current is stronger off Peru. An agent
equalizing these factors is possibly the differential effect of latitude (p. 211). Neither
sea-bottom contour nor coast-line trend appeared to have any effect (pp. 202-4).
Sinking of newly mixed water
The essential differences between the sinking of water by this mechanism and by
subsidence are considered (p. 214). The process seemed to have been in progress off
Caldera on the outer edge of the upwelling zone, and to have been brought on by
recent northerly wind (p. 140). It is presumed to have far-reaching importance in the
mixing of upper and lower layers and to occur most frequently in the neighbourhood
of the subtropical convergence.
DISTRIBUTION OF WATER MASSES
Surface
The convergence of sub-Antarctic and subtropical water which lies along the 30-
32° S parallels in g5—105° W, curves northwards on approaching the Chilean coast and
was found as far north as 24-26° S, in 70-71° W (Table V and Fig. 42, pp. 160 and 161).
As both these water-masses participate in its northward flow, the Peru Coastal Current
crosses a convergence.
Beneath the surface
At this convergence, the sub-Antarctic water sinks and is shown to send an arm north-
wards for some 10° of latitude beneath the subtropical layer (p. 161 and Fig. 42); and was
welling up to the surface at three localities (Figs. 20, 22 and 43). At a deeper level, a
more saline and comparatively warm return current of subtropical water (poor in
oxygen) was drawn southwards, and was welling up to the surface at San Juan,
Antofagasta, and possibly Cape Carranza, centres of exceptional activity (pp. 162-3,
Figs. 18, 24 and 45).
HORIZONTAL SURFACE CURRENTS
Highly saline tropical water (> 36-00 °/..) was not met within the limits of the
Coastal Current, but a highly saline wedge of warm water lay at some distance off the
coast both off southern and northern Peru (Figs. 16 and 63). Continuity in a counter-
current just here is not easily explained: the depth of its maximum salinity is shown to
SUMMARY 237
increase towards the south as it would if its origin lay at the surface westwards of the
region surveyed (p. 161, Table V). Convergence of this warm wedge with the coast at
two points (Callao and Arica) becomes significant when correlated with circumstantial
evidence.
Evidence of anticyclonic swirls
(1) Northerly coastal drift was of most account at two localities, off San Juan and off
northern Peru; i.e. where the wedge was farthest from the shore (‘Table I). (2) Surface
temperatures depressed over a wide area round these points showed them to be up-
welling centres (Fig. 16). (3) Here also southerly drift was noted offshore (Table I and
Fig. 14). (4) Off northern Peru, westerly set was marked. The probable existence off the
Peruvian coast of two large anticyclonic swirls is thereby demonstrated (pp. 191—2 and
Fig. 63), and receives confirmation from temperature and current relationship of the
wedges at San Juan and Callao (p. 192, Figs. on pp. 149 and 165). ‘The warm wedges
converging with the coast to the south of their respective upwelling centres appear
thus to be oceanic currents of compensation.
Permanence of anticyclonic swirls
Data of earlier observers are analysed. The agreement between (1) Schott’s up-
welling centres and variations in volume of upwelling already noted; (2) our records of
drift and those, notably, of Garcia, Ray, Dinklage and Somerville; and (3) the dual
convergence of warm water with the coast and the counter-currents reported by the
‘Mentor’, Lavalle, and Stiglich; indicate that the anticyclonic whirls are either
permanent or recurrent.
Cyclonic eddies
Inshore counter-currents, apparently making a series of small-scale coastal eddies,
were frequently recorded (p. 191). At Caldera and Bahia Herradura eddies are presumed
to have resulted from a southward flow inshore of water deflected east, flowing in
compensation for a local deflection of the offshore water west. At Caldera an eddy-like
appearance beneath the surface was given by sinking water (Figs. 8 and 23).
HORIZONTAL SUBSURFACE CURRENTS
Below the surface the two layers already noted—the arm of sub-Antarctic above, and
the subtropical return current below—are shown to have a coastal nature which is
emphasized with special reference to conditions in mid-Pacific and mid-Atlantic
(pp. 161, 194 and 200). The modifications they introduce into the arrangement of coastal
water-masses shows them to be subsurface currents compensatory for water drawn to
the surface by upwelling.
SURFACE SALINITY OF THE COASTAL CURRENT
The fact that upwelled water has a higher salinity than the surface of the adjacent
ocean in the south of the region, but is less saline than the adjacent ocean in the rest of
the region, is attributed to these subsurface currents of compensation (pp. 162-3).
17-2
238 DISCOVERY REPORTS
DEPTH AFFECTED BY UPWELLING
The trend of isotherms and isohalines below the surface is shown to be influenced
not only by upwelling water but by the structure of the compensating currents. The
determination of the depth from which upwelling takes place is confused by this second
factor. A minimum value of 40 m., a mean of 133 m., and a maximum of 360 m. are
suggested (pp. 200-1).
ORGANIC PRODUCTION
An attempt is made to ascertain the major effects of these hydrological processes on the
life of the region. Areas of exceptional upwelling are first shown to be exceptionally rich
in nutrient salts (p. 180, and Figs. 54, 57 and 58); and then to have a high phytoplankton
and zooplankton content (Table XIII). A new method of demonstrating the consump-
tion of nutrient salts by the phytoplankton is tentatively considered (pp. 184-9). The
results are shown to be in accord with what is known of the cycle of organic production
in other parts of the world: and they have been used to infer the conditions in the area
at periods earlier than the date of our visit (pp. 135, 186, 188, 201, 220).
Regional fertility
The permanence of upwelling centres suggests that these are perennially more fertile
than other parts of the coast: this and the paucity of phytoplankton in the warm wedges
and at their points of convergence with the coast (Callao and Arica, Appendix I), suggest
that the fertility of a locality is bound up with the position relative to it of the anti-
cyclonic swirls. At the same time the unfailing appearance of upwelling, even at such
localities of convergence, suggests that all localities are potentially fertile (pp. 211 and 219).
COLOUR OF THE CURRENT
The average bulk of phytoplankton varied at different distances from the shore in a
way suggesting that the area has not been adequately sampled. Nevertheless there were
signs that on average the yield is no heavier in the upwelling zone than at distances up
to 100 miles from the coast (Table XI, pp. 178-9). The green colour of the current,
on the other hand, was seldom found to extend beyond 30 miles from the shore. A
hypothetical explanation is advanced which relates the green colour to the zone where
illumination is lessened by cloud (p. 222).
Discoloration
Discoloration due to colours of purely animal nature appear to be rare. Between
Sts. WS 656 and 657 such a patch of brick red was discovered, due to a swarm of
euphausian cyrtopias. The yellow off Punta Aguja and the salmon colour at Pisco were
attributable to vegetable pigments, the former algal (of a symbiotic colonial radiolarian),
the latter directly or indirectly flagellate (pp. 174 and 173).
SUMMARY 239
Grounds are adduced for identifying the colours of very unusual appearance met with
off Pisco, Callao and the Guanape Islands (Plate XVI, figs. 6, 7 and 11) with the aguaje
phenomenon rather than with the appearance at the surface of normal animal plankton
(pp. 222 and 229-33).
AGUASE
A condition of the surface water in which discoloration, fish mortality and liberation
of hydrogen sulphide take a leading part, is known as aguajye. Compared with other
records, our results support the view that aguaje may result in coastal water from a
sudden rise in temperature. Under the apparently normal conditions of the present
survey, it was found to coincide with the northern anticyclonic swirl at those points
where its oceanic limb, the warm wedge, was converging with the coast. It appears also
to be brought on by convergence of the abnormal counter-current known as E/ Nino.
Aguaje, although an abnormal phenomenon in the sense that it may upset the balance of
nature, is therefore liable to occur in either normal or abnormal conditions (pp. 229-33).
The nature of aguaje is summarized: its effects are shown to vary from the mild met with
in 1931, to the extremes which kill plankton and fish, cause the guano birds to migrate,
and produce the ‘Callao Painter”’.
MORTALITY OF SQUIDS ON THE CHILEAN COAST
Large quantities believed to be Dosidicus gigas (Orbigny) were found washed up in
Talcahuano harbour, but no connection could be found between them and the abnormal
phenomena noted on the Peruvian coast (p. 233).
BOUNDARY OF THE PERU COASTAL CURRENT
Coastal and oceanic conditions contrasted
Results summarized in foregoing paragraphs have shown the more important bio-
logical and hydrological characteristics of the coastal current to be attributable to up-
welling of lower layers and their mixture with surface water masses. Equivalent
characteristics of the open ocean are contrasted in ‘Table XXII.
The distribution of surface isotherms seems the most comprehensive characteristic,
for isotherms usually run east and west parallel to latitude, but they change direction
under the preponderating influence of upwelled water and run parallel to the coast.
If their change of direction is taken as the western boundary, the whole area surveyed
by the ‘ William Scoresby’ lies within the Peru Coastal Current (Figs. 16 and 17). An
arbitrary boundary is suggested on the basis of Schott and Schu’s chart of mean annual
isotherms (Fig. 68).
Northern boundary and the Equatorial Counter-current
The northern boundary is shown to be easily recognizable as the convergence of
cool upwelled water of moderate salinity (> 35-00 °/,,) with the warm poorly saline
240 DISCOVERY REPORTS
(< 33:00 °/,.) Equatorial Counter-current (Figs. 42 and 70). The boundary was
crossed, off Capo Blanco, but had altered considerably within five days.
Table XXII. The Peru Coastal Current and the Peru Oceanic Current compared
Inshore conditions Offshore conditions
Currents Current northerly and counter-currents frequent | Drift mainly westerly
Vertical currents lead to vertical mixing Vertical mixing checked by
a discontinuity layer
‘Temperature Low High
Surface isotherms run north and south Isotherms run east and west
Salinity South of subtropical convergence: Low Lower
North of subtropical convergence: High Higher
Nutrient salts Constantly replenished Depleted
Colour Green, etc. Blue or indigo
Marine life Plankton abundant and largely littoral in character Plankton oceanic
Animals of economic importance, plentiful Animals of economic im-
portance, rare or absent
Southern boundary and the Cape Horn Current
Seasonal changes have been used, with fair precision it is believed, to determine the
southern limits of the Peru Coastal Current. Surface temperature on the west coast,
from 8 to 47° S, declined with advance of winter, in all but the parallels of 34-39° S
(Table IX). This anomalous rise becomes intelligible on the hypothesis that a former
period of active upwelling had existed between these parallels, a hypothesis receiving
support from established meteorological facts (pp. 226 and 227). These parallels come
under the influence of the Chilean monsoon and after their advent, a cessation of up-
welling may be presumed.
The southern limits of the Coastal Current, identified as the southernmost upwelling
centre, is consequently placed in 40° S, within a degree of Mossman’s division between
cyclonic and anti-cyclonic wind systems. In winter months, however, the southern
limit may be as far north as 33° S. It therefore varies with season. Southwards of 40°S
surface temperatures show no seasonal anomaly; this has been identified as the Cape
Horn Current.
CONDITIONS ON THE EAST COAST AND WEST COAST COMPARED
‘The essential characteristics of the Peru Coastal Current and its wealth of fauna and
flora are immediately traceable to the divergence of surface water from the west coast.
This is the means by which nutrient salts are brought to the surface, and its importance
is made evident by brief reference to conditions on the east coast of South America.
LIST OF REFERENCES 241
LIST OF REFERENCES
Acosta, J. DE, 1604. The Naturall and Morall Historie of the East and West Indies. London. [Reprinted
by Hakluyt Society, 1880, No. Lx.]
Agassiz, A., 1891. Reports on the Dredging Operations off the West Coast of Central America to the Galapagos,
etc., by the U.S. Fish Commission Steamer ‘ Albatross’. Bull. Mus. comp. Zoél. Harv., xxii, pp.
I-90.
ALEXANDER, W. B., 1928. Birds of the Ocean. New York, London (Putnam).
Amezaca, C. DE, 1885. Viaggio di Circumnavigazione della Regia Corvetta ‘Caracciolo’. Rome.
Araco [D. F. J]., 1840. Rapport sur les travaux scientifiques exécutés pendant le voyage de la frégate la
Vénus, commandée par M., le capitaine de vaisseau Du-Petit-Thouars. C.R. Acad. Sci., Paris,
XI, pp. 298-343.
Atkins, W. R. G., 1923. The Phosphate Content of Fresh and Salt Waters in its Relationship to the Growth of
the Algal Plankton. J. Mar. Biol. Ass. U.K., x11, pp. 119-50.
1924. On the Vertical Mixing of Sea-Water and its Importance for the Algal Plankton. J. Mar. Biol.
Ass. U.K.., XIII, pp. 319-24.
1925. On the Thermal Stratification of Sea Water and its Importance for the Algal Plankton. J. Mar.
Biol. Ass. U.K., x11, pp. 693-9.
— 1925. Seasonal Changes in the Phosphate Content of Sea Water in relation to the Growth of the Algal
Plankton during 1923 and 1924. J. Mar. Biol. Ass. U.K., x11, pp. 700-20.
— 1926. A quantitative consideration of some factors concerned in plant growth in water. Part Ii. Some
chemical factors. J. Cons. int. Explor. Mer, 1, pp. 197-226.
Atkins, W. R. G. and Witson, E. G., 1927. The Phosphorus and Arsenic Compounds of Sea-Water. J. Mar.
Biol. Ass. U.K., xiv, pp. 609-14.
Becuer, A. B., 1864. Navigation of the Pacific Ocean with an account of the Winds, Weather, and Currents
found therein throughout the year, pp. 128-31. London.
Beecuey, F. W., 1831. Narrative of a Voyage to the Pacific and Beering’s Strait, to co-operate with the Polar
Expeditions: performed in His Majesty’s Ship ‘ Blossom’. London.
BeLcuer, E., 1843. Narrative of a Voyage round the World, performed in Her Majesty’s Ship ‘ Sulphur’,
during the years 1836-1842. London.
BENT, S., 1869. An Address...upon the Thermometric Gateways to the Pole, surface currents of the ocean,
and the influence of the latter upon the climate of the world, pp. 22-4. St Louis.
Bercuaus, H., 1837. Allgemeine Lander- und Vélkerkunde. Stuttgart, 1, pp. 572-88.
1839. Physikalischer Atlas. Gotha.
1842. Sechs Reisen um die Erde der Kéniglichen preiissischen Seehandlungs-schiffe Mentor und Princesse
Louise innerhalb der Jahre 1822-1842. Breslau.
—— 1852. Phystkalischer Atlas. Gotha.
Beracu, W., 1728. A Voyage round the World: being an account of a remarkable enterprize begun In the Year
1719, chiefly to cruize on the Spaniards in the great South Ocean, relating to the True historical Facts
of that whole Affair. London.
Boucainvit_e, M. Le Baron be, 1837. Journal de la navigation autour du globe de la frégate La‘ Thétis’ et
de la corvette ‘L’Espérance’ pendant les années 1824, 1825 et 1826. I, pp. 555—-9; I, pp. 147-8.
Paris.
Bowers, G. M., 1906. Dredging and Hydrographic Records of the U.S. Fisheries Steamer ‘ Albatross’ for 1904
and 1905. Rep. Comm. Fish. Fiscal Year 1905 and Special Papers, Bur. Fish., Document No. 604,
pp. 52-66.
Bowman, I., 1916. The Andes of Southern Peru, pp. 126-29. New York.
Brooks, C. E. P., 1929. Climate. A handbook for Business Men, Students and Travellers. London.
Bucuan, A., 1895. Report on Oceanic Circulation, based on the Observations made on board H.M.S. * Challenger’,
and other Observations. Rep. Sci. Res. Voy. ‘Challenger’. A Summary of the Scientific Results.
Appendix (Physics and Chemistry, Part viir).
242 DISCOVERY REPORTS
Bucuanan, J. Y., 1886. On Similarities in the Physical Geography of the Great Oceans. Proc. Roy. Geogr.
Soc. Lond., vim, pp. 753-69.
1910. The Colour of the Sea. Nature, Lxxx1v, pp. 87-9.
Carranza, Luis, 1891. Contra-corriente maritima, observada en Paita y Pacasmayo. Bol. Soc. geogr. Lima,
I, pPp- 344-5.
CarriLLo, D. C. N., 1892. Estudios sobre las corrientes ocednicas y especialmente de la corriente Humboldt.
Bol. Soc. geogr. Lima, 11, pp. 72-110.
CarRuTHERS, J. N., 1928. The Flow of Water through the Straits of Dover as gauged by continuous Current-Meter
Observations at the Varne Lightvessel. Part I. Min. Agric. and Fish., Fish. Invest., Ser. 2, x1, No. 1.
1935. The Flow of Water through the Straits of Dover as gauged by continuous Current-Meter Observa-
tions at the Varne Lightvessel (50° 56’ N.—1° 17' E.). Part II. Min. Agric. and Fish. Invest.,
Ser. 2, xiv, No. 4.
CHILE, 1918. Derrotero de la Costa de Chile. Valparaiso.
CizzA DE LEON, PEDRO DE, 1553. Parte primera de la chronica del Peru. Que tracta la demarcacion de sus
provinctas: la descripcion dellas. Las fundaciones de las nuevas ciudades. Los ritos y costumbres de los
indios. Y otras cosas estranas dignas de ser sabidas. Martin de Montesdoca, Seville. [Translation by
Clements R. Markham published by Hakluyt Society 1864.]
CLEMENS, W. A., 1935. Red ‘“‘ Water-Bloom” in British Columbia Waters. Nature, CXXXV, p. 473.
Crowes, A. J., 1933. Influence of the Pacific on the Circulation in the South-West Atlantic Ocean. Nature,
CXXXI, pp. 189-91.
Coxer, R. E., 1918. Ocean Temperatures off the Coast of Peru. Geogr. Rev., V, pp. 127-35.
CoLLincwoop, C., 1868. Observations on the Microscopic Alga which causes the Discoloration of the Sea in
various parts of the World. Quart. J. micr. Sci., xxx, p. 85.
CoLmeEnares, J. I. [18—?]. Derrotas desde el Puerto del Callao & los comprendidos hasta el grado de 42 de
latitud Meridional || su regresso [y] las de ida {| y| vuelta del Callao 4 Panama con distinction de las
Estaciones en que se emprehende la Navegacion. (Madrid ?]
CotnetTT, J., 1798. A Voyage to the South Atlantic and round Cape Horn into the Pacific Ocean for the purpose
of extending the Spermaceti Whale Fisheries, and other objects of commerce. London.
Dampirr, W., 1703-5. A New Voyage round the World. 1, 1703; 1, 1705. London (James Knapton).
Daronbeau, B., et CHEVALIER, Y. E., 1840. Voyage autour du Monde exécuté pendant les années 1836 et 1837
sur la Corvette La Bonite. Physique, 1 and 2, Observations Météorologiques.
Darwin, C., 1845. Journal of Researches into the Natural History and Geology of the countries visited during
the voyage of H.M.S.‘ Beagle’ round the world, under the command of Capt. FitzRoy, R.N. London
(John Murray).
Deacon, G. E. R., 1933. A General Account of the Hydrology of the South Atlantic Ocean. Discovery
Reports, VII, pp. 171-238.
DEUTSCHE SEEWARTE, 1896. Alas des Stillen Ozeans. Taf. 6-9. Hamburg.
Duprrrey, L. I., 1829. Voyage autour du monde...sur la Corvette de la Majesté, ‘La Coquille’,
pendant les années 1822, 1823, 1824 et 1825. Hydrographie et Physique.
1831. Carte du mouvement des Eaux a la surface de la Mer dans le Grand-Océan Austral. Voy. de la
Coquille. Hydrogr.
Ecuicuren, V., 1894. Estudios demograficos de la ciudad de Piura. Bol. Soc. geogr. Lima, Iv, pp. 68-79.
Exman, V. W., 1905. On the Influence of the Earth’s Rotation on Ocean-Currents. Ark. Mat. Astr. Fys., 1
2, No. 11, pp. I-52.
1928. A Survey of some Theoretical Investigations on Ocean Currents. J. Cons. int. Explor. Mer, 11,
PP: 295—327-
FErRREL, W., 1860. The Motions of fluids and solids relative to the Earth’s surface, comprising applications to the
winds and the currents of the ocean, p. 55. New York.
Finpiay, A. G., 1853. Oceanic Currents, and their connection with the proposed Central-America Canals.
J. Royal Geogr. Soc. xx1I, pp. 223-32.
Fitz-Roy, R., 1839. Narrative of the Surveying Voyages of His Majesty’s Ships ‘ Adventure’ and ‘ Beagle’,
between the years 1826 and 1836. U1, p. 505, Appendix, pp. 31-45.
LIST OF REFERENCES 243
FLEMING, J. A., 1930. The Last Cruise of the ‘Carnegie’. ‘Terr. Magn. and atmos. Elect., Baltimore, xxxv,
No. 1, p. 22.
Forses, H. O., 1914. Notes on Molina’s Pelican (Pelecanus thagus). Ibis, Ser. 10, 11, pp. 403-20.
Frezigr [A. F.], 1716. Relation du voyage de la Mer du Sud aux cétes du Chily et du Perou, fait pendant les
années 1712, 1713, 1714. Paris. [Translation, London, 1717.]
FUNNEL, W., 1729. A voyage round the World. Being an account of Capt. William Dampier’s Expedition into
the South Seas in the ship ‘St George’. London (James Knapton).
Garcia y Garcia, A., 1870. Derrotero de la Costa del Peru. Lima.
Gerkik, A., 1877. Elementary Lessons in Physical Geography, p. 147. London.
Gitcurist, J. D. F., 1914. An enquiry into fluctuations in fish supply on the South African coast. Mar. Biol.
Rep. No. 2, pp. 8-35.
Gran, H. H., 1927. The production of Plankton in the coastal waters off Bergen, March—April 1922. Rep.
Norweg. Fish. Invest., 11, p. 8.
GuNcKEL, Huco, 1928. Sobre el Espino maulino (Acacia cavenia, Mol.). Rev. Chil. Hist. nat., Xxxt,
PP: 3475-
Guntuer, E. R., 1936. Variations in the behaviour of the Peru Coastal Current—with an historical
introduction. J. Royal Geogr. Soc., Lxxxvill, No. 1, pp. 37-65.
Haptey, Gro., 1735. Concerning the Cause of the General Trade-Winds. London. (Reprinted 1896.
Neudrucke von Schriften und Karten iiber Meteorologie und Erdmagnetismus, herausgegeben von
Prof. Dr. G. Hellmann, No. 6. Berlin.)
Hatt, B., 1825. Extracts from a Journal written on the Coasts of Chili, Peru, and Mexico, in the years 1820,
1821, 1822. Edinburgh.
Harpy, A. C., and Guntuer, E. R., 1935. The Plankton of the South Georgia Whaling Grounds and Adjacent
Waters, 1926-1927. Discovery Reports, x1, pp. 1-456.
Hart, T. J., 1934. Red ‘‘ Water-Bloom” in South African Seas. Nature, CXXxXIv, p. 459.
Harvey, H. W., 1928. Biological Chemistry and Physics of Sea Water. Cambridge.
—— 1934. Annual Variation of Planktonic Vegetation, 1933. J. Mar. Biol. Ass. U.K., XIx, pp.
Time
Hawes, Sir Ricuarp, 1622. The Observations of Sir Richard Hawkins Knight, in his voiage into the
South Sea. Anno Domini 1593. [Reprinted by the Hakluyt Society in 1878.]
HELLAND-Hanssn, B. and Nansen, F., 1926. The Eastern North Atlantic. Geofysiske Publikasjoner, Oslo,
Iv, No. 2.
Horrmann, P., 1884. Zur Mechanik der Meeresstrémungen an der oberfldche der Ozeane. Berlin (E. S. Mittler
und Sohn).
Hotimann, Karr. z. SEE, 1882. Aus den Reiseberichten S.M.S. ‘Elisabeth’. Ann. hydrogr. Berlin, x,
Pp- 357-62.
HorneLt, J., 1917. A new Protozoan Cause of Widespread Mortality among Marine Fishes. Madras Fish.
Bull. No. 11, pp. 53-66.
Humpotpt, A. DE, 1810. Recueil d’Observations Astronomiques, d’Opérations Trigonométriques et de Mesures
Barométriques, faites pendant le cours d’un Voyage aux régions équinoxiales du nouveau Continent,
depuis 1799 jusqu’en 1803, I, p. 317- Paris.
1811. Essai politique sur le Royaume de la Nouvelle-Espagne, 1, pp. 759-69. Paris. (Translation,
London, 1811.)
Humpo.pT, ALEXANDER DE, and BonpLanp, AIME, 1826. Voyage aux régions équinoxiales du Nouveau Conti-
nent, fait en 1799, 1800, 1801, 1802, 1803 et 1804, x1, Chap. xxix, pp. 228-30 Paris.
Humpo pt, A. von, 1849. Cosmos: a sketch of a physical description of the universe, 1, pp. 311-14. London.
[Translated by E. C. Otté.]
Hurcuinson, T. J., 1873. Two Years in Peru, 1, pp. 219-25. London.
Jounstong, A. K., 1848. The Physical Atlas—A series of Maps and Notes illustrating the Geographical dis-
tribution of natural phenomena.
— 1850. The National Atlas of historical, commercial and political Geography, p. 48. London.
JounsTonE, J., 1923. An introduction to Oceanography. Liverpool Univ. Press.
D XIII
244 DISCOVERY REPORTS
Juan [y SantaciLia], J. and ULLoA, A. pe, 1748. Relacion Historica del viage a la America meridional hecho
de orden de S. Mag. para medir algunos grados de Meridiano Terrestre, y venir por ellos en
conocimiento de la verdadera Figura, y Magnitud de la Tierra, con otras varias Observaciones
Astronomicas, y Phisicas. Madrid. [English translation, London, 1807.]
Kemp, S., Harpy, A. C., and Macxintosn, N. A., 1929. Discovery Investigations. Objects, Equipment and
Methods. Discovery Reports, 1, pp. 141-232.
Kenprew, W. G., 1922. The Climates of the Continents. Oxford.
KERHALLET, CHARLES PHILIPPE DE, 1856. Considérations générales sur L’Océan Pacifique. Paris (Paul
Dupont).
Kerr, Ropert, 1824. A General History and Collection of Voyages and Travels, arranged in systematic
order: forming a complete History of the origin and progress of navigation, discovery, and commerce,
by sea and land, from the earliest ages to the present time. London.
Kine, P. P. and Firz-Roy, R., 1850. Sailing directions for South America. Part II. La Plata, Patagonia,
Magellan Strait, Tierra del Fuego, Falkland and Staten Islands, Chile, Bolivia, and Peru. London.
KRUMMEL, OTTO, 1911. Handbuch der Ozeanographie, 2nd edit., 1. Stuttgart.
LarticuE [J.], 1827. Description de la céte du Pérou entre 19° et 16° 20’ de latitude Sud; et renseignemens sur
la navigation des cétes occidentales d’ Amerique depuis le Cap Horn, jusqu’a Lima. Paris.
Lastres, D. E. C. y, 1935. La Corriente del Pert. Rev. del Cons. Oceanogr. Ibero-Americano. Afio v1,
Num. 1, p. 45.
Laucuton, J. K., 1870. Physical Geography in its relation to the prevailing winds and currents, p. 240.
London.
LavaLte, J. A., y Garcia, 1917. La contra corriente ecuatorial como causa determinante del fenomeno marino
conocido con el nombre de ‘‘ Aguaje”. Bol. Soc. geogr. Lima, xXXIII, pp. 313-30.
LavaLLe, J. A. DE, 1917. Informe preliminar sobre la causa de la mortalidad de las aves ocurrida en el mes de
marzo del presente afio. Mem. Compafiia Admin. Guano, vill, pp. 61-84.
—— 1924. Estudio de la Emigracion y Mortalidad de las Aves Guaneras ocurridas en los meses de Mayo y
Junio del Afio 1923. Compafia Admin. Guano. Seccion Tecnica.
McEwen, G. F., 1912. The Distribution of Ocean Temperatures along the West Coast of North America
deduced from Ekman’s Theory of the upwelling of cold water from the adjacent Ocean Depths. Int.
Rey. Hydrobiol., v, pp. 243-86.
1916. Summary and Interpretation of the hydrographic observations made by the Scripps Institution
for Biological Research of the University of California, 1908-1915. Univ. Calif. Publ. Zool., xv,
PP- 255-356.
—— 1929. A Mathematical Theory of the Vertical Distribution of Temperature and Salinity in Water under
the action of Radiation, Conduction, Evaporation, and Mixing due to the resulting Convection. Bull.
Scripps Inst. Oceanogr., Tech. Ser., 11, pp. 197-306.
MarsHaLt, S. M., and Orr, A. P., 1927. The Relation of the Plankton to some Chemical and Physical Factors
in the Clyde Sea Area. J. Mar. Biol. Ass. U.K., x1v, pp. 837-68.
1928. The Photosynthesis of Diatom Cultures in the Sea. J. Mar. Biol. Ass. U.K., xv, pp. 321-60.
Mattuews, D. J., 1916. On the amount of phosphoric acid in the sea water off Plymouth Sound. J. Mar. Biol.
Ass. U.K., x1, pp. 122-30.
1923. Oceanography, Physical. Dictionary of Applied Physics, 111, pp. 665-92.
Maury, M. F., 1844. Remarks on the Gulf Stream and Currents of the Sea. Amer. J. Sci. and Arts, XLVI,
pp. 161-81.
—— 1855. The Physical Geography of the Sea. London.
MELO, R., 1906. Derrotero de la Costa del Peru. Lima.
Micuat1, Evis L., 1921. Effect of Upwelling water upon the organic fertility of the sea in the region of Southern
California. Spec. Publ. Bishop Mus., No. 7, Part 1, pp. 555-95.
Mut, H. R., 1899. The International Geography. London.
Mosere, E. G., 1928. The Interrelation between Diatoms, their Chemical Environment and Upwelling Water
in the Sea off the coast of Southern California. Proc. Nat. Acad. Sci. Washington, xiv,
pp. 511-18.
LIST OF REFERENCES 245
Moserc, E. G., and Granam, H. W., 1930. The Distribution of Oxygen in the Pacific as an index of the
Circulation of the water. Internat. Geodet. Geophys. Union, Stockholm Assembly, Section of
Oceanography, August 1930.
Moserc, E. G., SEIwe_t, H. R., Granam, H. W., and Paut, J. H., 1930. The Phosphate-Content of the
surface-water in the Pacific as related to the circulation. Internat. Geodet. Geophys. Union, Stock-
holm Assembly, Section of Oceanography, August 1930.
Mossman, R. C., 1909. The Monsoons of the Chilean Littoral (Preliminary Note). Trans. Roy. Soc. Edin.
XLVI, pt. I, pp. 137-41.
Murpny, R. C., 1923. The Oceanography of the Peruvian Littoral. Geogr. Rev. x11, pp. 64-85.
1925. Bird Islands of Peru. New York and London (Putnam).
1926. Oceanic and Climatic Phenomena along the West Coast of South America during 1925. Geogr.
Rev., XVI, pp. 26-54.
Nansen, F., 1902. Oceanography of the North Polar Basin. Norweg. North Polar Exped. 1893-96, Sci.
Res. 11, No. 9. Kristiania.
Natuansonn, A., 1906. Uber die Bedeutung Vertikaler Wasserbewegungen fiir die Produktion des Planktons
im Meere. Abh. Sich. Ges. Wiss., XxIx, pp. 358-441.
NISHIKAWA, T’., 1901. Gonyaulax and the discolored water in the Bay of Agu. Annotationes Zoolog. Japon. Iv,
pt. I, pp. 31-4.
OrriciaAL AMERICAN HANDBOOK, 1892. Peru. Bur. Amer. Republ. Bull. No. 60, p. 8. Washington.
Orsicny, A. D’, 1835-43. Mollusques. Voy. dans L’Amer. Meérid., v, partie 3, pp. 52-4.
PAULSEN, O., 1934. Red ‘‘ Water-Bloom” in Iceland Seas. Nature, CXXXIV, p. 974.
PereEz-Rosaces, V., 1857. Essai sur le Chili, pp. 64-6. Hamburg.
Perit-THouars, A. pu, 1842. Voyage autour du Monde sur la frégate‘La Venus’ pendant les années 1836-1839.
v1, Physique.
Perzet, F. A., 1896. La Contra-corriente ‘‘ El-Nino”, en la costa Norte del Pert. Bol. Soc. geogr. Lima, v,
Pp. 457-61.
PFEFFER, GEORG, 1912. Die Cephalopoden der Plankton-Expedition. Ergeb. Plank.-Exped. Humboldt-
Stiftung, u, F. a, p. 516. Kiel.
Prior CHARTS OF THE SouTH Paciric Ocean, No. 2601 (published quarterly). U.S. Hydrographic Office,
Washington.
Puts, CAsar, 1895. Oberfldchentemperaturen und Strémungsverhaltnisse des Aequatorialgiirtels des Stillen
Ozeans. Archiv der Deutschen Seewarte, xvu, No. 1.
Rarmonp1, D. A., 1891. Fendmeno llamado El Pintor. Bol. Soc. Geogr. Lima, 1, pp. 58-67.
—— 1897. Geografia fisica. Bol. Soc. geogr. Lima, vil, pp. 241-310.
Ray, R. C., 1896. The West Coast of South America, comprising Magellan Strait, Tierra del Fuego and
Outlying Islands. Hydrographic Office Publication, No. 89, Washington.
RAYLEIGH, Right Hon. Lord, 1910. Colours of Sea and Sky. Nature, LXxxil, p. 48.
Rayner, G. W., 1935. The Falkland species of the crustacean genus Munida. Discovery Reports, x,
PD 20084 5.
Rectus, Eviske, 1876. The Ocean, Atmosphere and Life being the second series of a descriptive history of the
phenomena of the Life of the Globe. [Translation by B. B. Woodward], pp. 80-1, London.
Ripeway, R., 1912. Color Standards and Color Nomenclature. Washington, A. Hoen and Co.
Romme, Cu., 1806. Tableaux des vents, des marées et des courans qui ont été observés sur toutes les mers du
globe; avec des réflexions sur ces phénomenes, 1, pp. 237-8, Paris.
Russet, F. S., 1927. The Vertical Distribution of Plankton in the Sea. Biol. Reviews, U, pp. 213-
62.
1928. The Vertical Distribution of Marine Macroplankton. VI. Further Observations on Diurnal
Changes. J. Mar. Biol. Ass. U.K., xv, pp. 81-99.
— 1928. The Vertical Distribution of Marine Macroplankton. VII. Observations on the behaviour of
Calanus finmarchicus. J. Mar. Biol. Ass. U.K., xv, pp. 429-54.
1931. The Vertical Distribution of Marine Macroplankton. X. Notes on the Behaviour of Sagitta in
the Plymouth Area. J. Mar. Biol. Ass. U.K., xvil, pp. 391-414.
246 ; DISCOVERY REPORTS
Russe_L, F. S., 1931. The Vertical Distribution of Marine Macroplankton. XI. Further Observations on
Diurnal Changes. J. Mar. Biol. Ass. U.K., xvul, pp. 767-84.
Sanpstr6M, W. J., 1919. The Hydrodynamics of the Canadian Atlantic Waters. Canadian Fisheries Expedi-
tion, 1914-15, pp. 221-403.
Savace, R. E. and Harpy, A. C., 1935. Phytoplankton and the Herring. Fish. Invest., Min. Agric. Fish.,
Ser. 11, xtv, No. 2.
ScumipT, J., 1931. Oceanographical Expedition of the ‘ Dana’, 1928-1930. Nature, Cxxvi1, pp. 444—6, 487-9.
ScHoTt, GERHARD, 1891. Die Meerestrémungen und Temperature-verhdltnisse in den Ostasiatischen Gewdssern.
Petermanns Geogr. Mitteilungen, xxxvil, p. 215.
1928. Die Verteilung des Salzgehaltes im Oberflachenwasser der Ozean. Ann. hydrogr. Berlin, LVI,
pp. 145-66.
—— 1931. Der Peru-Strom und seine nérdlichen Nachbargebiete in normaler und anormaler Ausbildung.
Ann. hydrogr. Berlin, L1x, pp. 161-9, 200-13, 240-52.
~_— 1932. The Humboldt Current in relation to Land and Sea Conditions on the Peruvian Coast. Geography,
xvil, No. 96, pp. 87-98.
1935. Geographie des Indischen und Stillen Ozeans. Hamburg.
Scuott, G. and Scuu, F., 1910. Die Warmverteilung in den Tiefen des Stillen Ozeans. Ann. hydrogr.
Berlin, XxxvIII, pp. 2-25.
ScureIBeEr, E., 1927. Die Reinkultur von Marinen Phytoplankton und deren Bedeutung fiir die Erforschung der
Produktionsfahigheit, des Meerwassers. Wiss. Meeresuntersuch., N.F., xvi, No. ro.
Scuweiccer, E. H., 1931. Observaciones oceanograficas sobre la corriente de Humboldt. Bol. Compania
Admin. Guano, VII, pp. 3-39.
Sciater, W. L., 1913. The Peruvian Guano Islands. 'The Ibis, Ser. 10, 1, pp. 709-12.
SEEMANN, B., 1853. Narrative of the Voyage of H.M.S. ‘ Herald’ during the years 1845-51.
SemPLeE, W., 1931. Plankton Changes on the Coast of Ecuador. Nature, 127, p. 743.
SeweLL, R. B. S., 1928. Geographic and Oceanographic Research in Indian Waters. Part IV. The
temperature and salinity of the coastal water of the Andaman Sea. Mem. Asia. Soc. Bengal, 1x,
Pp. 131-206. P
SHEPPARD, G., 1931. Plankton Changes on the Coast of Ecuador. Nature, 127, pp. 629-30.
Smitu, W. A., 1899. Temperate Chile. London.
SOMERVILLE, B. T., 1923. Ocean Passages of the World — Winds and Currents.
SoutH AMERICAN Pinot, 1927. Part III. Comprising the West Coast of South America from Cabo Tres
Montes to Panama Bay. London.
STIGLICH, GERMAN, 1918. Derrotero de la Costa del Peru. Lima.
1925. El fenomeno maritimo del Aguaje. Rey. Mar. Peru, x, No. 1, pp. 25-40.
Supan, A., 1891. Das Kalte Auftriebwasser. Petermanns Geogr. Mitteilungen, XXXVI, p. 293.
Sverprup, H. U., 1930. The Origin of the Deep-Water of the Pacific Ocean as indicated by the Oceanographic
work of the ‘Carnegie’. Internat. Geodet. Geophys. Union, Stockholm Assembly, Section of
Oceanography, August 1930.
1931. Some Oceanographic Results of the ‘Carnegie’s’ Work in the Pacific. The Peruvian Current.
Hydrogr. Rev., vill, pp. 240-4.
—— 1933. On vertical circulation in the ocean due to the action of the wind with application to conditions
within the Antarctic Circumpolar Current. Discovery Reports, VII, pp. 139-70.
SzyszLo, VITOLD DE, 1925. Influencia de las corrientes maritimas sobre el clima de Sur América. Bol. Soc.
geogr. Lima, xLIl, pp. 59-65.
Tart, J. B., 1930. The Surface Water Drift in the Northern and Middle Areas of the North Sea and in the
Faroe-Shetland Channel. Part I. Fisheries, Scotland, Sci. Invest., 1930, No. 1.
—— 1932. The Surface Water Drift in the Northern and Middle Areas of the North Sea and in the Faroe-
Shetland Channel. Part II. Fisheries, Scotland, Sci. Invest., 1931, No. 111.
Tessan, U. pe [? 1844]. Carte des Courants et des Températures del’ Eau a la surface de la Mer, observés a bord
de la ‘Vénus’ en 1837, 38 et 39.
1844. Voyage autour du Monde sur la Frégate ‘La Vénus’, x. Physique v, Paris.
LIST OF REFERENCES 247
TuHouLetT, J., 1928. Le Courant de Humboldt et la Mer de ’Ile de Paques. Ann. Inst. oceanogr. Monaco et
Paris, v, fasc. 11, pp. 188-200.
Tizarp, T. H., Mosevey, H. N., Bucuanan, J. Y. and Murray, J., 1885. Rep. Sci. Res. Voyage H.M.S.
‘Challenger’. Narrative, I, pt. I, p. 363; pt. 11, p. 9go.
Torrico, R., 1933. Por qué el Peru necesita un estudio de la Corriente que lleva su nombre. Mem. Cons.
Oceanogr. Ibero-Americano, No. 14, pp. I-19.
UNANuE, J. H1poiiro, 1806. Observaciones sobre el clima de Lima, y sus influencias en los seres organizados, en
especial el Hombre. Lima.
VALLAUX, CAMILLE, 1930. The Question of the Humboldt Current. Hydrogr. Rev., vi, pp. 66-74.
VaNcouVvER, G., 1798. A Voyage of Discovery to the North Pacific Ocean and round the World in which the
coast of North-West America has been carefully examined and accurately surveyed. (London.
Wacter, RIcHarD, 1748. A Voyage round the World in the years 1740-1744 by George Anson Esq. London
(Knapton).
Wesser, V. A., 1859. Journal of a voyage round Cape Horn. Swansea.
WEDDERBURN, E. M., rg11. Some Analogies between Lakes and Oceans. Int. Rev. Hydrobiol. Bd. tv,
Pp. 55-64.
WILHELM, O., 1930. Las mortandades de jibias (Omastrephes gigas) en la Bahia de Talcahuano. Bol. Soc.
Biol. Concepcion (Chile), 1929-30, pp. 23-38.
Wiikes, C., 1845. Narrative of the United States’ exploring expedition during the years 1838-1842, 1, pp.
161-310. Philadelphia.
WIiL1AMs, J., 1799. Thermal Navigation being a series of Experiments and Observations tending to proove, that
by ascertaining the Relative Heat of the Sea-Water from time to time, the Passage of a Ship through
the Gulf Stream and from deep water into Soundings, may be discovered in Time to avoid Danger,
although (owing to tempestuous weather,) it may be impossible to heave the Lead or observe the Heavenly
Bodies. Philadelphia.
Wixson-Barker, Sir D., 1931. Plankton Changes on the Coast of Ecuador. Nature, 127, p. 975.
WirtTe, E., 1871. Zur Theorie der Meeresstrémungen. Ann. Physik Chemie, CxLit, pp. 281-93.
— 1880. Das Emporquellen von kalten Wasser an meridionalen Kiisten. Ann. Hydrogr., Berlin, vit,
p- 192.
1910. Aspiration infolge der Mischung von Wasser. Geogr. Anzeiger, XI, pp. 223-4.
Wo tr, Tu., 1879. Bemerkungen tiber die Galdpagos-Inseln, thr Klima und thre Vegetation, nach Beobachtungen
in den Monaten August bis November 1875. Verh. Ges. Erd. Berlin, v1, pp. 245-56.
WiLverstorr-Urgalr, B. von, 1862. Reise der Oesterreichischen Fregatte ‘ Novara’ um die Erde in den Jahren
1857, 1858, 1859, p. 245. Vienna.
Wist, G., 1935. Humboldt-Strom, nicht Peru-Strom! Petermanns Mitteilungen, pp. 439-41.
ZARATE, AUGUSTIN DE, 1555. Historia del descubrimiento y conquista del Peru, con las cosas naturales que
senaladamente alli se hallan, y los sucessos que ha avido. Anvers. [Translated in Kerr, Robert, 1824—
““A general History and Collection of Voyages and Travels”. Vol. 1v, pp. 348-50. (Blackwood.)]
ZORELL, FRANZ, 1928. Der “ El-Nifio”-Strom im Fahre 1925. Ann. Hydrogr., Berlin, Lv1, pp. 166-75.
248 DISCOVERY REPORTS
JN) eel 2) OND). I
Volumes of phytoplankton (c.c.). Table of provisional measurements
Cape Carranza Antofagasta (north)
\iVs) Gon <<a! Wis Ooms —<.82'5
Gon << Ae 632 < 25 Guanape Islands
593 Bie 633 < 25/;V. few diatoms WS 675 —
594 754 634 < 25 GW <= 25
595 < 75 635 <= 25 77 < 252 Be
ID SZ PS 25
597 >4150 Arica 679 < 25°
598 >150 WS 640 < 258 680 < 50° Amphipoda
599 >100 641 < 25 681 < 25
600 >125 642 < 25 para 682 < Alpe
601 >4150 p43 <2 Site uf oe < 25 | almost absent
BO) << 25 < 50
Pichidanque Bay 638) <= 25
WS 602 < 25 V. few Lobos Islands
603 < 25 San Juan WS 691 < 258
604 < 25 WS 647. < 257 690 < 259
605 < 25 648 < 25 692 < 25}
610 < 25 649 25 wy << Ay!
609 < 25 650 < 25 Decrease 694 < 25 Few
608 < 50 651 < 25 Gt. diminution 695 < 25 V. few
606 < 25 646 < 25 V. few 696 < 25
Coy) << A 657, <= 75 689 < 25] Diatoms
656 >300 688 < 25| almost absent
ae 655 >150 687. <: 25
ig) | << BE 5A << 25
614 < 50 654 < lee Punta Aguja
oe S25 653. < 2s | WS 097 eae,
MW =< 5 os
618 — Callao (July) 699 390
O17) = 25 WS 663 < 258 700 < 25
620 — 644, = 2510 7or < 25 Absent
619 25 665 < 25 702 < 50 Few
eg oe : z Peshaad ie S ee V. few
Antofagasta (south) C725 anostabeeot 705 < 50
WS 622 < 25) Diatoms 670) = 925 70050
623 < 25, almost 669 > 50 70725
624 < 25 | absent 668 < 25
625 <100 Capo Blanco
626 < 75 Callao (August) WS 709 => 50?
627 >150 WS 728 >4100 710 < 50’ Gt. diminution
628 = 729 < 75 711 <100 Absent
630 < 25 Few 730 _ 712 Fo) —~c
629 < 25 Few 731 25 V. gt. dim. Gay = Te) Digtoms
practically
732 =< 50 TEA <5 0ll ee
733 < 50 708 <I100
734 <100 722 > 50
The table includes only the stations on lines normal to the coast. The data represent the settled volume
of all organisms taken by the gran net hauled vertically from a depth of 100 m. to the surface except where
otherwise indicated. The measurements are to the nearest 25 c.c. Figures in heavy type denote suspected
patches of phytoplankton.
'N50Hdepth o-5m. 4 N50 V depth 4o-om. 8 N 50 V depth 80-0 m.
2 N50V , 30-0m. 5 » » 45-0m. 8 » 9 go-om.
Se eo ey a eo eae
g Sn lspe) ROO—O)In:
A partial list of contributors to the literature of the Peru Coastal Current
DISCOVERY REPORTS
APPENDIX II
249
Year of
publication
Contributor Ship Weanon
observation
Leon, Pedro de Cieza de — 1547-
Zarate, Augustine de _ 1543-50
Acosta, J. de = 1571-85
Fletcher, F. *Pellican’ 1578-79
Hawkins, Sir R. ‘Dainty’ 1594
Ovalle, Alonzo -= —
Dampier, W. ‘Revenge’ 1684
Funnel, W. “St George’ 1704
Frezier, A. F. “S.Joseph’,‘ Mary Anne’ etc. 1712-14
Betagh, W. ‘Speedwell’ 1720
Walter, R. ‘Centurion’ 1741
Ulloa, A. de “Incendio’, ‘Rosa’, etc. 1740-44
Colnett, J. ‘Rattler’ 1793-94
Unanue, J. H. — —
Romme, Ch. — —
Humboldt, Alexander H. F. von — 1802
Colmenares, J. I. ‘“Limeno’ 1805-08
Hall, B. ‘Conway’ 1820-22
Lartigue, J. ‘La Clorinde’ 1822-23
Duperrey, L. I. ‘Coquille’ 1823
Harmssen, J. H. ‘Mentor’ 1823
‘Princesse Louise’ 1826-27
Dirckinck de Holmfeldt — 1825
Bougainville, H. Y. P. P. de ‘Thetis’ and ‘L’Espérance’ 1825
Beechey, F. W. ‘Blossom’ 1825-28
King, Ps Ps ‘Adventure’ 1829
Wieyens Bene b). ‘Princesse Louise’ 1831
Wendt, J. W. ‘Princesse Louise’ 1831 and 1833
Reynolds, J. N. ‘Potomac’ 1832-33
Rodbertus, J. 'T. ‘Princesse Louise’ 1837 and 1839
Berghaus, H. — =
(‘Mentor’, ‘ Princesse (1823-39)
Louise’)
Fitz-Roy, R. ‘Beagle’ 1835
Darwin, C. ‘Beagle’ 1835
Darondeau, B. and ‘Bonite’ 1836
Chevalier, Y. E.
Tessan, U. de ‘Vénus’ 1837-38
Arago, D. F. J. (‘ Vénus’) (1837-38)
Belcher, E. ‘Sulphur’ 1838
Wilkes, C. ‘Vincennes’ 1839
Johnstone, A. K. — —
Seemann, B. ‘Herald’ 1845
Woolridge, O. ‘Spy’ 1847
Findlay, A. G.
Maury, M. F.
Kerhallet, C. P. de
£553
1555
1608
1628
1622
1649
1703
1729
1716
1748
1748
1798
1806
1806
1810
1811
1826
1825
1827
1829
| See
J Berghaus 1842
See Humboldt
1826
1837
1831
1850
\See
{ Berghaus 1842
1835
See Berghaus 1842
1837
1839
1842
1852
1839
1848, 1850, 1856
1853
See Raimondi 1891
1853
1855
1856
250
DISCOVERY REPORTS
APPENDIX II (cont.)
Contributor Ship Wee? OE MEER Gs
observation publication
Perez-Rosales, V. — _- 1857
Webber, V. A. ‘Hercules’ 1858 1859
Ferrel, W. _- — 1860
Wiillerstorf-Urbair, B. von ‘Novara’ 1859 1862
Becher, A. B. — _— 1864
Bent, S. — — 1869
Garcia y Garcia, A. — — 1870
Hutchinson, T. J. — 1871-73 1873
Witte, E. — -- 1871
~- _ 1880
Laughton, J. K. — — 1870
Dinklage, L. E. Charlotte’ 1874 See Schott 1891
Wolf, Th. = 1875 1879
Hoffmann, P. ‘Moltke’ 1881-83 1884
Amezaga, C. de “Caracciola’ 1882 1882
Hollmann ‘Elisabeth’ 1882 1882
Buchanan, J. Y. — 1885 1886
— _- IgIo
Ray, R. C. — — 1890, 1896
Denker, J. ‘Atalanta’ 1891 |
Lubken, G. ‘Ancona’ a J See Zor
Raimondi, D. A. — aa 1891, 1897
Carranza, L. = = 1891
Carrillo, D. C. N. — — 1892
Official American Bulletin -— — 1892
Eguiguren, V. — — 1894
Puls, C. — — 1895
RezetghepAG — — 1896
Smith, W. A. — — 1899
Melo, R. -— — 1906
Bowers, G. M. ‘Albatross’ 1904-05 1906
Mossman, R. C. — — 1909
Kriimmel, O. = = IQII
Lavalle, J. A., y Garcia —- — 1917
Coker, R. E. — 1908 1918
Bowman, I. = IQII 1916
Chile, Derrotero de la Costa de - — 1918
Stiglich, G. = — 1918
- = 1925
Stolzenbach “Karnak 1916-18 See Schott 1931
Lavalle, J. A. de _- IQ 7-24 1917-24
Somerville, B. T. — = 1923
Murphy, R. C. — IQIg-25 1923
— _ 1925
— — 1926
Szyszlo, V. — — 1925
Oetcken, L. ‘Odenwald’ 1924-25
Goose, W. ‘Wiegand’ 1925
Hensen, O. “Spreewald’ 1925
Kilp, H. “Negada’ 1925 - See Zorell
Kunstler “Kellerwald’ 1925
Piper, O. ‘Planet’ and ‘Poseidon’ 1925
Volquardsen ‘Oldenburg’ 1927
APPENDIX II (cont.)
DISCOVERY REPORTS
251
Contributor Ship | Year of Year of
observation publication
Gunckel, H. = 1927 1928
Zorell, F. (‘Atalanta’, etc.) (1891-1927) 1928
Thoulet, J. (‘ Challenger’) (1875) 1928
Schott, G. (‘ Charlotte’) (1874) 1891
(‘Emden’) 192
‘Nitocris’ ae oe
Brooks, C. E. P. = — 1929
Wilhelm, O. — 1930 1930
Sverdrup, H. U. (‘ Carnegie ’) (1928-29) 1930
Vallaux, C. — — 1930
Schweigger, E. H. — 1929-30 1931
Sheppard, G. = 1923- 1931
Semple, W. = = 1931
Wilson-Barker, D. -- —- 1931
Torrico, R. ‘William Scoresby’ 1931 1933
Wiist, G. — — 1935
Note. Contributors are listed, as far as possible, in the order in which their observations were made.
Ship and date in brackets indicate the expedition from which the author cited has mainly drawn his data.
APPENDIX Itt
Table giving date, hour, position and nomenclature of the colours in Plate XVI
Plate Biss
Ill Position
——| Date Hour Station Colour nomenclature*
: Latitude | Longitude
Fig. W
Te) Lu. ve 32. || Ogoo! | 44520; aS Gap Dull blackish green xLI- 33'"” GY-G,m
2 7. Vi. 31 | 1400 | 25° 36’ 70° 39’ 30” ox 44’ l
3 7. Vi. 31 | 1400 | 25° 36’ 70° 39° 30” — 44! j
4 8. vi. 31 | ogoo | 23° 32’ 36” | 70° 38’ 30” | WS 622 | Diamine green 37. GB-G,m
5 Onnviengin || u500me23 a2 30.8 71228) WS 629 46
Gmale2s5e vile 30 | 1300)\|) 13415. 30" | 76% 207 WS 658 | Ochraceous-salmon x 13’ OY-O, 6
Paez Oe vil ot || TLZ0) 122 09) 30° || 77-15" Site of | With patches of 14’
WS 662 | cinnamon rufous 11’ Orange,z
S26. vie 3 || 1230) | 122/08) 77° 16 WS 661 | Porcelain blue 43” G-B
9 | Io. vii. 31 | 1630 | 8° 19’ 30” | 79°05’ 45” | WS 677 | Olivine 35” Green, d
10 |} 10. vii. 31 | 1700 | 8° 24’ 30” | 79° 03’ Sea green 41' BB-G,k
Hi eLOuVvile Bu | 1745) || 8430130" | 7O: CO: 20” i
Tee | LOS vile 38 | LLZO. |) TOs 33) 79° 08’ Deep Delft blue 45'" BG-B, k
Lee e25avilt 3 T)| 1400) 235 21 omen 46
14. | 16. vii. 31 | 1130 | 10° 33’ 79° 08’ Pale Russian blue 45"’ BG-B, f
Tee e2Se ville 9 | LLOO! |) 31m 12, 72° 14! 47 G-—BB,j
Note. Owing to practical difficulties
are not always in exact correspondence with these references.
D XIII
* Ridgway, 1912.
in the making of such records, the colours shown in Plate XVI
19
DISCOVERY REPORTS
252
AP PEN DISeay:;
List of observations on surface temperature and wind'
fee
Position :
; d2
Date Station Distance Temp. Nag
Hour : : offshore °
1931 WS Latitude Longitude ane C.
S WwW Direction | Force
10. V 1200 47° 19’ 30” Gy Aik <30 ENE 2
1600 SxE 3
2020 | 587 | 46°14'30" | 75° 55’ 36” 30 11-7 Ss 3
0000 SSE 5
TELE, 0400 S 4
0800 44° 28" 70m Is 70 12:0 ESE 3-4
1200 ESE 3-4
1600 ESE 4
2013 | 588 42° 42’ Fg Oe 56 12°73 E 4
0000 Easterly 4
12.V 0400 ESE 4-5
0800 41° 03’ 30” 74. 10’ 12 12°66 ESE 4-5
1200 ESE 5
1600 Corral Exs 5
2000 SE 23
0000 ESE 5-7
15.V 0400 Corral Easterly i
0800 39° 53° 73027. 2 98 SE 2
1200 BO misao" CBee By HO" 18 11-22 SE 2
1600 38° 34’ 73° 46’ 30" 13 II'1g _ °
2009 589 38° 04" 752k 22 10:67 Westerly 2
0000 87a a4 73° 56’ 12 12°18 — Co)
16. v 0337 36° 59’ ama On II 11°56 SE I
0800 Talcahuano tithe L3G NE I-2
1200 — fo)
1400 590 fo) II-2 NE 2
2000 — fo)
0000 — fo)
18. v 0400 = o
0800 NExN 4
2380) 1 590 3547) 72.306 5, 27 1ne7 NxE 3
1359 | 592 | 35°46) 72” 42’ 30" 4°5 1146 | E 1-2
1629 | 593 | 35 36 72° 44" 4°5 1145 | NWxN 2
L752 lS 0401) G35 3) il age a5o! 9 11-69 = O-1
1943 | 595 | 35 3512" | 72° 56 14°5 11-62 aaa o-1
2206 596 AG BS GO" 73 O7s0n 24 11°85 — o-I
0000 NxE I
19. V 0400 N 2
0643 | 597 | 35° 39°42” | 73° 19' 30” 32 12°36 | NNE 4
0800 NNE 4
1025 598 35043" Bus 2 40 12°12 NNE 4
1200 NNE 2
1410 | 599 | 35°41'30" | 73°43’ 49 12°87 | ESE 3
' The Table gives only the more important of the observations that have been made. Additional records
of wind made while the ship was in harbour, and of surface temperature made between the observations
here listed, are to be had on application to the Discovery Committee.
* Wind data are taken from the deck log book and are additional to those shortly to be published in the
station list.
DISCOVERY REPORTS 253
APPENDIX IV (cont.)
Wate Stati Rosition Distance T Wind
Hour OR : offshore SOP:
L932 WS Latitude Longitude anvils Calle
W Direction | Force
19.V 1600 ESE 2-3
1915 | Goo | 35° 40’ 73055, 58:5 13°57 | SW 3
20.V OOI5 601 Bb 3013On 74° 18' 79 13°65 SSE 3
0400 ESE 2
0800 SExE 2
1200 35° 14’ 06” GI lly Gio SEXE 2
1700 35° 02" TD PIS, 10 12:0
2000 34° 39’ Ws PRY. 18 12°35 Light airs o-I
0000 12-91 SE 2
21.V 0400 ? 20 12°81 Ss) 2
0800 Valparaiso SExsS 4
1200 Light airs 0)
1600 ” °
2000 » °
0000 Easterly 13
28.Vv 0400 Light airs fo)
goo 32° 40" 71° 39° 8 13°5 » oan
1300 602 32° 04! 45 71° 34’ O5 14:02 SSW 2
1502 603 22a Ob, 71° 40’ Goh 14°32 SW 2
1655 604 32° 05’ 71° 45° 30" 10°5 14:00 E 2
2030 605 32° 05" 71° 50’ 14°5 13°91 E 2)
0000 14:08 = o-I
29.V 0400 14°39 N I
0745 606 32° 09’ 36” Thy Be IOI 16-2 S 3
1200 iS) 2
1600 16-38 SxW 4
1718 607 324050301 74° 04! 129°5 16°42 iS) 4
2000 Southerly 4
0000 15"19 SSE 4
30. Vv 0440 608 Que Gy! Ske" 30 02) 74:5 1401 S 5-6
0800 S 6
III5 609 Bite Gin eye 72° 34 51 14°25 S 5-6
1600 Sx W 5
1840 610 Bile 415. 30 2m 20M 24°5 14:00 S) 3
0000 Ri 2H’ 72° 00’ 30" 19°5 13°89 —= °
Vi 0400 15 15°75 S) 3
0800 13°05 ) 3
1030 Coquimbo 13°39
1200 SW 2
1600 SW I-2
2000 SW I
0000 ay °
3. Vi 0400 Coquimbo = f°)
0800 = f°)
1200 — fo)
1415 2 15-10
1500 2-3 14°64
19-2
254 DISCOVERY REPORTS
APPENDIX IV (cont.)
Position :
Date H Station aioe Temp. Wind
1931 a WS Latitude Longitude ie ues =
W Direction | Force
3. Vi 1530 Fy 14°42
1600 9 13°55 SW 1-2
1630 12 14°58
W7/O2) 14 TAA
1800 29° 34° We 39. 14 13°95
2000 611 2.0 male iw 2 30 10 15°03 NE 2
0000 28° 47’ 71° 44" 16 15°2 NNW I
4. Vi 0400 33 14°41 SW I-2
0800 Fig[> ahs) APL 71° 56’ 44 16°46 WSW I-2
1120 612 27° 08’ 30” 72° o1' 30” 54 16°61 SW 3
1600 SxE 3
2000 SW 3
0000 SSE 3
5. Vi 0400 = )
0640 613 270530. 70° 58’ I 13°1 ESE 2
0830 614 2/7206, 30" 71° 00 42” 2 13°45 ESE 2
IIIg 615 27° 05" 30” 71° 04" 5 14:2 ESE 2
I511 616 27° 08’ 71° 10’ 8-5 14°88 WNW I-2
1825 617 27° 09’ 30” Gps ln! fas! 13°5 15°9 WNW 2
2250 618 27° 09' 723 On II 151 WNW I
0000 — fo)
6. vi 0440 619 21703 N30 71° 30 27 16°56 = °
0800 NNW 2
1150 620 27° 04' 30” Fl Pay 21 16°5 ENE 2
1600 N x W I-2
2000 — o-I
0000 AAS? Gee Ti AQe 415 16°67 NNE 2
7. Vi 0400 26° 28’ 25” fie sey 2S) 28 16-15 SE 2
o815 26° 02’ 70° 48’ 15” 8:5 15°7 5 2
0845 75 16-7
OgI5 6-25 16:2
0930 55 15°68
0958 | 14°78
1000 | 25° 47 70° 48’ 45" 50 4) 14°45
1002 | | 143
IOIS 14°38
1030 es)
1045 5525 Ape
1100 14:28
HES) 14°39
1130 14735
1145 14°38
1200 14:4 S 3
1230 25° 28" 70° 39" 2°75 | 14°55
1300 25° 24’ TOM omA GE 6°75 15:28
1315 752 258
1330 83 16°3
1337 16°5
1345 16-7
DISCOVERY REPORTS 255
APPENDIX IV (cont.)
| Position
Date Hour Station - ke Temp. ee
HH a‘ WS Latitude Longitude eas cae
S Ww on Direction | Force
7.Vi 1352 16-76
1400 Ss 16°79
1407 16°75
1415 16:69
Hage 1649
1445 Aly it ai! 70° 38’ 6 16-09
1500 15°65
1515 E92
1530 15°70
1545 16-18
1600 2°3 16:68 SSW 3
1615 16°55
1620 16°53
1625 16°49
1630 24° 52' 30” 70° 35’ O°5 16°30
1635 16°30
1700 3 16°31
1800 2°25 16:8
1900 3°6 17°17
2020 621 24s 2771300 70° 43° 6 17°20 Southerly 4-5
0000 24° 02' Gp rat 35 17°41 ) 4-5
8. vi 0400 30°5 16-69 S 4-5
o810 622 2B 263 Ou 70° 38’ 30” 7103} 14°10 E 4
1029 623 Pe ayy! figs 70° 41’ 2 14-14 E 4
1315 | 624 | 23°31'45" | 70° 44" 30 4°7 1431 | S 3
1520 | 625 | 23°31’ 40" | 70° 47’ 7 13°93 | S 3-4
1735 626 2B Or 70° 50’ 9°8 14:09 S 4
2040 627 PESO Phsy. 70° 52' 30 12 15:01 iS) 4
2354 | 628 | 23° 25° 70° 55° 15 1519 | S 4
g. Vi 0400 23m 244 71° 09’ 27 15°6 SSW 5
0500 23% 23) 71° 12' 20” 31 17°59
0600 17°51
0goo 629 2B 2iIe 301 Gf PAY 46:5 18-04 SSW 5
1200 ) 5
1600 S 4-5
1815 2 44°5 17°9
1830 17°5
2007 630 23° 22’ 71° 06’ 25°5 17°31 S 3
0000 630 S 2
10. Vi 0400 630 Northerly 3
0754. 630 2213) 30 70° 56’ 16°5
0838 631 2aval2) 70° 49’ II°5 16°5 NE 2
IIIO 632 23° 10’ 70° 46’ 30” 9 S77 NE 2
1325 633 PES iy 70° 43° 30” 6:5 15°85 Nx W 2-3
1523 634. 22010! 70° 40’ 30 4 I5‘II Nx W B
1658 635 22m 120 30u 70° 39’ 30” 2 14°9 NxW 4
1900 3 15°0
1920 15°31
2000 22 70° 46’ 30” 8 16-61 Northerly I-2
2020 8 16-15
256
DISCOVERY REPORTS
APPENDIX IV (cont.)
Position 5 Wind
Date Hens Station ae ee Temp. a
LO3z Ws Latitude Longitude Se cc:
iS) W Direction | Force
10. V1 2040 15°81
2050 15°63
2100 15°30
2110 Day” Gey 70° 47’ 7 15°31
2120 15‘15
2125 eet)
2130 4:25 14°80
2135 14°60
2140 14°45
2145 1:35
25 T4735
2200 14°14
2115 I4*15
2225 3°5 13-98
2235 13-98
2250 Py Bey. Omari 1°5 13°9
2300 Antofagasta 0°3 14°68
0000 N. Easterly 2
II. Vi 0400 Antofagasta N. Easterly 2
0800 N. Easterly | 1-2
1200 = fc)
1600 — °
2000 — fC)
0000 18; I
16. vi 0400 Antofagasta E I
0645 14:8
0700 O'5 14:6
O715 14:64
0730 2°5 15°2
°745 T5335
0800 23° 35 70° 39 3°5 15"4 —. Ot
o815 15°6
0830 4°25 16-6
0845 5°75 | 17°44
0900 To 17°59
0920 17°64
0940 17°69
1000 9:0 17°70
1030 17°70
1100 10 17°70
1140 10°5 17-2
1200 23° 06’ 70° 45/ 8-25 15°75 = o-I
1230 16-41
1300 8-5 16-19
1400 9°5 16-10
1500 5 16:06
1530 2-3 16-06
1600 i5o7/ Southerly 2
1605 15°72
1610 15°71
DISCOVERY REPORTS
257
APPENDIX IV (cont.)
Position ‘
Date ee Station eee Temp. Wing
MOR) Ws Latitude Longitude . nae oC.
Ss) Ww Direction | Force
16. Vi 1615 I°5 15°82
1620 7
1625 15°65
1630 Boma Th 70° 20° O'5 15°6
1635 15°57
1640 15°5
1645 15°65
1700 8 15°7
So 9 1595
1800 II 16-10
1900 14-15 16:62
2020 636 22° 04’ 30” 70° 36° 20 16-23 WSW 3
0000 27 16°59 W 2
17. Vi 0400 25 16°71 SW Z)
o815 10 17°63 NNE 2
ogoo 17°2
1000 4 16-7
1030 16°5
1100 159
1130 O'S 15°52
1600 Iquique WSW B
2000 — )
0000 — )
18. vi 0400 Iquique = fc)
0800 = °
1200 — )
1600 SW 1-2
1800 4 16°3
1900 6 16-00
2008 637 19° 48’ 70° 22! 9°5 15°67 NNW 2
0000 18 18-59 SW 2
19. Vi 0400 35 18°45 SW 2
0520 638 18° 54’ 30” 71° 06’ 41 18-62 SE 3-2
0800 SE 3
1230 639 18° 44’ 70° 48' 23°5 18-62 SE I-3
1440 21°5 19'I
1600 14 18-7 = I
1630 8-5 18-1
1730 5 17°25
1745 640 18° 28’ 70° 23° 36" 3 16°57
1916 641 18° 27’ 30” 70° 26’ 30” 5 17°62 — o-I
2110 642 18° 287 24” FOuB2ul2n 10 17°91
2324 643 18° 30’ 70° 42’ 48" 17 18-12 WSW 2
20. Vi 0400 18-5 17°66 WSW 2
0800 8 15°92 Light airs
1200 5 161 Light airs
1300 16°45
1415 8 16:8
1430 6 16°35
258
DISCOVERY REPORTS
APPENDIX IV (cont.)
+
1 The original log entry 15:18° C. appears to be a misreading.
Position oie:
Date Station eee ||) hemp:
T9372 ae Ws Latitude Longitude pee “Ge
S Ww
20. Vi 1440 4 15-9
1450 Mollendo 3 15°5
1530 3-4 16-22
1600 6 16°5
1700 16°53
1715 fe) 17°10
1800 ? 10 17°3
2010 644. TOS 5) 127 72° 39 P15 16°43
0000 212 15°49
21. Vi 0400 Bare, 15°54
0800 ? 12 15°32
1100 ? 10 15°03
1200 27 15-21
1300 24 15°12
1400 ? 1-2 14°79
1435 O75 Mapes
1500 1-2 14°45
1600 6 14°5
2028 645 15° 42’ 18" 75° 03 13°5 14°85
0000 22 15°03
22. Vi 0405 646 ry Gy. sale 31 14°81
0800
1155 | 647 | 15° 19/12" | 75° 11’ 30” 125 | 13°79
1313 648 15° 19’ 30” Gey igh 2 13°82
1449 | 649 | 15° 20° 75. 16’ 30” 3°75 | 14:19
1634 650 15e 227.300 SIS PEF 11-75 14°43
1930 651 ity aie! 5a 373°. 22 14°86
0000 38 15°5
23. Vi o100 45 15-681
0200 54 16-21
0300 63 16-78
0400 72 16°85
0500 81 17-21
0600 go 17-82
0650 652 Low 2Iy or 70m 20ml2an 96 18-82
0800
1035 uray)
1200 16° 21’ 76° 33’ 30” 100 19°25
1500 132 19°48
1600 141 19°40
1710 | 653 | 16° 54’ Wms 150 18-79
2000
0000
24. Vi OO15 654 16° 36’ 76° 55° 30” 124 19:22
0400 120
0500 III 19:20
0600 102 18-78
Ogio 655 16° 08’ 76° 22’ 81-5 17:26
1200
Wind
Direction | Force
E 12
Southerly 3
S. Easterly
ENE 4-5
SSE 3-4
NE 4
ESE 3-4
Southerly 3
Southerly 3
Exs 4
SE 4
SE 6-7
ESE 5
ESE 4-5
SE 3-4
SE 3-4
SE 4-5
SE 5-6
SE 5
SE 6
SE 5-6
SE 5
SE 5
SE 5
SE 4-5
ESE 4-5
SExs 4-5
ESE 4
ESE 4
DISCOVERY REPORTS 259
APPENDIX IV (cont.)
Position ; :
Date Pout Station me i BCE Tempe Wind
1931 Ws Latitude Longitude eee °C.
iS) WwW Direction | Force
24. Vi 1405 656 Theis 2030" 76° 07’ 30” 62 16°24 SE 4
1600 SE 4
1900 | 657 | 15°38'18" | 75°53’ 24” 42 15°36 | SE 4
2000 SSE B
0000 36 15°69 ESE 3
25. Vi 0400 20 14°89 SExsS 4
0500 16 15°24
0600 15°29
0800 8 15°38 SE 5
1200 S 3
1228 658 13° 45' 30” 76° 20’ 23 19*10 SW 4-5
1240 Pisco
1600 SW 4-5
2000 SSW 3
2120 659 13° 37 48” 76° 20’ 8:5 17°6 NWxN 3
0000 12 16°59 NWxN 3
26. vi 0400 IIS 17°68 NNW 2
0800 8-11 17°91 SSW I
0935 660 ide ARN Gyo! apap Tk 7h! — — SW 2
1200 661 12° 08’ 77° 16! 6 16:61 SW 2
1245 662 12° 09’ 30” Chip ay 6 16:86 SW 2-3
1600 Callao Southerly I-2
2000 Southerly I
0000 Light airs Co)
I. vii | 0400 Callao SE I-2
0800 = )
1000 o's 16°8
1100 5°5 17:2
II40 663 12° 0g’ 36” Shap ay. 6 17°21 ESE 1-2
1325 664 iad? sini! Yo} Gye Gh 9 17°21 SE 3
1615 665 AS” 11g" sites 77° 21' 48" 13°5 17°55 S 4
1836 666 12° 18’ 30” Gap? XO Boy" 17°84 SE 3
2030 18-4
2045 191
2055 667 2 eoR malo 7730) 30! 19°13 SE 4
0000 SSE 3
2. Vii o100 44 19°45
0300 62 Ig°I
0400 78 17°81 SSE 4-5
0600 go 17°62
0700 99 18°39
0737 668 12° 48’ 30” 78° 45' 48" 104 18-88 SExE 4
1200 102 SExE 4
1400 85 18-0
1455 669 TIP” Bye ayo! 78° 21’ 36” 77 17°22 SE 5
1600 SE 45
2012 670 Ww” gaps eh 78° 13/ 48” 64 19:21 SE 4
0000 671 12° 10’ 48” 77. 5Q) 124 48°5 19°33 SE 4
3. vii | 0400 SE 5
D XIII
260 DISCOVERY REPORTS
APPENDIX IV (cont.)
Position p
: Wind
Date H Station oe Boca enaps
1931 aie WSs Latitude Longitude s ie °C.
WwW Direction | Force
3. Vil | 0800 17°33 SE 4-5
1200 Callao = °
1600 Southerly I-2
2000 Southerly 2-3
0000 SE I-2
8. vii | 0400 Callao _- °
0700 4 16°65
O715 6 16:9
0730 6 17°35
0805 672 12° 09’ 42” a As 6 17°33 SSE 3
0930 : 4 I7"I
1200 Callao SE 1-2
1600 SSE 3
1645 5°5 16°85
2012 673 Die 2ses0n 77° 38 9 17°32 SSE 3
0000 12 18°85 Southerly 1-2
g. Vii | O©400 20 19°69 Southerly 2=3
0800 26 19°50 ESE 3
1200 Om 530m 78° 55’ 39 20°6 ESE 3
1600 20°58 S 3
1800 51 20°59
IgI5 674 g° 00" 79° 40° 56 20°36 ESE 3
2215 IFS) 19°5
2300 47 19°38
0000 40 17°22 E 2-3
IO. vii | O100 17°75
0200 17°6
0300 17:28
0400 16°5 17°09 E 2
0500 10 16°72
0600 16°50
0700 16:27
0800 16°35 E I-2
0830 Salaverry 1°75 16°35
1200 SW I
1305 675 8° 14’ 30” OmIsOr 1°75 16:00 SW I
1413 676 8° 17’ 79° O1' 30” & 16°71 SSW 2
1525 677 8° 19’ 30” 79° 05’ 45" 9°5 16:82 SSW 2
1600 SSW 1-2
1700 8 17°99
1745 6°5 17°8
1824 678 Seaseson 78° 57’ 8 16°85 SW I
2000 679 8° 38’ 79° O1' 30” 12°5 17°39 SSW 2
2145 LFS)
2200 17°4
2238 680 8° 44" 79° 15° 26:5 17°4 SW I
II. vii | O100 681 8° 49’ 79° 24" 36:5 19°44 SE 2
0320 682 8° 53° 79° 33° 46°5 20°04 SE 2
0400 Southerly I
DISCOVERY REPORTS
APPENDIX IV (cont.)
261
Position ; Wind
Date rete Station ce ae Temp. ee
1931 WS Latitude Longitude Beer ac:
S W Direction | Force
II.vii | 0800 SSE 3
1200 On size 36 20°25 SSE 3
1600 10° 07” 29 20°23 SxE 3
2000 683 NOn ai7u hehe Gh Tly 24 20°18 SExS 3-4
0000 17 20°23 SE 3
12. vii | 0400 SE 3-4
0800 17 18-4 SSE 3
IOI5 684 12° 09’ 30” ap Sy 6 17°26 SSE 3
1200 Callao Ss I-2
1600 S) I-2
2000 Ss I-3
0000 SE 2
15. Vii | 0400 Callao Southerly i
0800 Southerly 2
1200 — )
1600 SW 2
1716 685 12° 09’ 30” Gfgfe wets 6 17-12 SxE 3
2000 II°5- 18-3 SW x W 1-2
2100 19 17°71
0000 26°5 17°53 SSW °
16. vii | O100 25 19°91
0200 30 20°02
0300 34 20°02
0400 40 19°9 SW 2
0500 45 20°23
0800 55 20°05 SSW 3
1200 10° 32’ 79° 12’ 68 20:08 SSW 2-3
1300 75 19°86
1600 80 19°82 SSW 2-3
1800 ? I0° 00" 87 20°42
2000 09° 49’ 93 20°20 SSW 3-4
0000 20°20 SE 2-3
17. vii | 0036 686 CO mn 25: GOn 80° 22’ 104°5 20°24 SE 4-5
0400 SE 5
0800 104. 20'8 SE 5
1200 ? 08° 39’ 97 19°6 SSE 4
1300 19:2
1400 ? 08° 27’ 100 18-87
1500 18-78
1600 97 19°01 Ss 3
1800 18-9
1900 207° 58’ 19:00
2000 1g'10 S) 4
2100 104 19°8
2220 687 07° 42’ 82° 09’ 116 19°64 SE 4-5
0000 SE 4-5
18. vii 0400 SE 3-4
0800 SSE 3-4
1156 688 07° 19’ 81° 35’ 78 18-65 SSE 2-3
DISCOVERY REPORTS
APPENDIX IV (cont.)
Position : Wind
Date H Station Pee Temp. 4
1931 oo) WS Latitude Longitude | ° ae °C.
S WwW Direction | Force
18. vil 1600 19:00 SSE 2-3
1920 689 07° o1' 81° 09! 51 18°55 SSE 3
0000 SSE 2-3
Ig. Vil | 0230 690 07° 03’ 80° 40’ 36” 40 18-14 SSE 3-4
0400 18-26 Southerly 2
0600 691 06° 59’ 45” 80° 15’ 24 17°38 SE 2a8
0800 SxW 3
1020 692 06° 29' 15” 80° 33’ 6 17°4 S I-3
1200 17°4 SE 3
1310 693 06° 35/ 12” 80° 40’ 14 17°84 SSE 3
1435 18 18-10
1508 694 06° 38’ 80° 49' 54” 21°5 18-15 SSE 3
2100 695 06° 48’ 12” 80° 55’ 32°5 18-14 SSE 2
0000 SE 3
20. Vii | 0030 696 06° 54’ 48” 81° 02’ 42 18-23 SSE 3
0400 SSE 2
0800 Lobos de = °
Tierra
1200 SE I
1600 SE 2-3
2000 SSE 3
0000 10 18-03 — °
2I.Vil | o400 Lobos de a )
Tierra
0500 10 17°89
0600 10 17°69
0700 7 17°62
0800 4°75 — I-2
0930 I°5 17°2
1000 1°5 17°15
1025 697 05° 55° 30” 81° 09’ 1°25 16-50 SSW 3-4
1142 698 Osim soi 81° 09/ 45” 2:25 16-60 Sx W 5
1255 | 699 | 05° 54’ 81° 11’ 42" 4°5 1779 | SxW 4
1432 700 On Ge Sie L530) 8:5 18-26 Sx 5
1700 701 05° 48’ Sim220307 17 18-49 S 3-4
2000 iS) 3-4
2225 702 05° 38’ 81° 40’ 37 18-33 S 3-4
0000 S 3
22. Vil | 0300 18-25 s 3
0330 18:27
0400 18-3 SW 2
0430 18-3
0500 18-21
0530 18-27
0600 18-24
0700 703 05° 34’ 82° 11’ 30” 68 18-18 SE 2-3
0800 SE 2-3
1200 SSE I-2
1600 18-80 SW 2
DISCOVERY REPORTS
APPENDIX IV (cont.)
263
Position ; Wind
Date H Station ae Foie Temp.
1931 a WS Latitude Longitude g eee “(Ce
S WwW Direction | Force
22. Vii | 1700 704 05° 33° 82° 47’ 103 18-64 SE 2
2000 SSE I
2130 18-41
2200 18°5
2230 18-42
2300 18-61
2330 18:59
0000 18-54 SW I-2
23. Vii | 0030 18-27
o100 18-39
0130 18-48
0200 18-95
0230 | 705 | 05° 35°30" | 83°41’ 45" | 157 19°03 | SSW I-2
0400 SSW I-2
0800 Exs I
0955 | 706 | 05°37'30" | 83° 58’ 174 19°74 | ESE 2-3
1200 ESE 2
1530 707 O55 370300 84° 31’ 30” 207 20°69 SE 3
1600 SE 2
2000 190 20°2 SE 3
0000 163 20-00 NE 4-5
24. Vili | 0200 146 19°6
0400 SExE 2
0430 135 19:00
0530 128 18°55
0630 fy 31%) 19:21
0755 19°48 | SE 3
0900 2145 WP 7)
0930 154 20:09
1008 166 20°00
1130 ? 154 19°70
1200 04° 17’ 30" | 83°27 150-130 | 19°65 | SE 3
1315 P 144 19°18
1400 ? 135 18-82
1600 ? 121 18-95 SExE 3-4
2030 ? 65 18-89 ESE 3
2130 257 19:00
2200 ? 50 19:00
2245 708 04° 18’ 82° 05’ 47 18-52 SSE 2
0000 SSE 2
25. Vii | 0400 SSE 3-4
0430 43 17-9
0600 33 17:0
0630 16°83
0700 16-9
0730 22 17:06
0800 17:09 SSE 3-4
0830 15 18-21
0900 II 20°34.
0935 8 21°34
264 DISCOVERY REPORTS
APPENDIX IV (cont.)
Position 5
Date Hur Station 2 ae Temp. Wing
1931 WS | Latitude | Longitude | “Ti, | °C:
S WwW Direction | Force
25. Vil 1000 4 21°48
1030 I 22°40
1040 709 04° 17 81° 16’ 45” 05 22°63 SSW 5
1220 710 04° 18’ Sim 2Or5e 4 21°54 S 5
1352 Gaia 04° 19’ 30” 81° 27’ II 21°19 iS) 5-6
1600 S 5-6
1845 | 712 | 04° 20! 81° 37’ 45” 19°5 20°44 | S 4-5
2000 S 5-6
2155 713 04° 20’ 81° 47’ 31 16°84 SSE 3-4
26. vii | O100 714 04° 20’ 81° 57’ 30” 40 17:00 SxE 4
0330 38 17:00
0400 16-91 S) 4
0430 35 16°83
0500 32 17°68
0530 28 18-92
0600 24 19°15
0730 14°5 19°48
0800 II's 17°7 iS) 4
0930 2 17°3
0937 I 16:8
0945 Talara 0°25 16:8
1200 S 4
1600 iS) 4
2000 iS) 4
0000 S 5
30. vii | 0400 Talara Southerly 2-3
0800 SSE I-3
1200 Southerly 3
1600 SW 4
1625 0°5 16:8
1730 8 17°97
1800 II5 18-9
1830 15 19°9
1930 23 20°18
2000 27 20:00 SW 4
2030 32 HPA)
2200 44 19°2
2230 04° 17’ 82° 05’ 48 18-39
2300 48 19:02
0000 Southerly 3-4
3I. vii | 0030 48 19°85
0100 49 20°15
0130 49 20°7
0200 50 211
0400 58 2117 ) 3
0800 61 21°93 SSW 4
0830 58 228
0900 53 23°1
utetete) 39 23°55
1200 35°5 23°87 SSW 3
DISCOVERY REPORTS 265
APPENDIX IV (cont.)
Position .
Date Hace Station Pee Temp. Wang
1931 WS Latitude Longitude pat °C.
iS) Ww : Direction | Force
31. vil 1230 31 23°9
1300 02° 16’ 81° 29’ 29 2471
1500 13°5 24"4
1600 715 OA? i 15 81° 04’ 3 24°3 S 3
1720 716 02° II 81° 09’ 8 24°43 ) 3
1920 717 O2— 12: 81° 18’ 30” 18 24°22 SSW 3
I. Vili | 0025 718 Ozma liiy Shit 2a)" Shey" ae 23°85 SWxs 3
0440 719 Oza le 81° 53’ 53 22°99 SSW 2
0800 SSW 2-3
1200 02° 25’ 81° 49’ 57 Southerly 4-5
1230 22°78
1430 66 22°40
1539 74 ET)
1640 84 21-00 Southerly 5-6
1730 720 O2 052) 5. 82° 19’ 30” gI 21-06 S 4
2000 95 20°7 ) 4-5
2100 IOI 20°2
2300 105 19°95
0000 107 19°79 Ss 5-6
2. Vill | O125 721 03° 29’ 82° 51’ 108 19°15 Sx W 4
0400 19°05 SxW 4
0500 18-69
0800 SE 3-4.
1030 722 04° 20’ 24” 83° 03 107 18°55 SE 3-4
1200 SE 3-4
1600 S 4
2000 18-40 SE 4-5
2130 723 05° 91’ 20” 83° 49’ 155 18-44 SE 4-5
0000 159 18-87 SE 4
3. Vili | 0300 176 18-97
0400 185 19°49 SxE 5
0500 190 20:00
0630 724 05° 35° 42” 84° 33’ 203 20°06 SSE 4-5
0800 SxE 5
1200 227 20°30 SSE 4
1430 725 06° 25’ 85° 04’ 12” 241 20°13 SE 5-6
1600 SE 5-6
1700 19°90
1800 19:20
2000 IQ'15 SSE 5-6
2100 247 19°58
2200 249 20°01
2300 253 19°62
0000 20°5 SSE 6-7
4. Vili | Oo15 726 07° 20’ 85° 12’ 30” 257 20°02 SE 6
0400 SE 5-6
0800 ESE 5
0920 19°6
1200 07° 45° 84° 30’ 221 SE 4
266 DISCOVERY REPORTS
APPENDIX IV (cont.)
Position ;
: Wind
Date Hate Station me ee Temp.
1931 WS Latitude Longitude anles °C.
Ww Direction | Force
|
4. Vill | 1230 19°30
1600 SE 5
2000 SE 5-6
2130 19°70
0000 199 20°08 SE 6
5. Vili | 0400 190 18-89 SE 5-6
0800 18-40 SExE 5
1200 09° 12’ 30” 82° 00’ 15” 182 17°90 SEXE 5
1600 163 18-4 SE 5
2000 I51 19:00 SExs 5
0000 130 18-48 SE 5
| 6. vili | 0400 117 18-65 SE 5
| 0800 96 18-72 SE 4-5
1200 10° 37’ 7Om5ugon 72 18-62 SE 4
1600 57 18-3 SE 5
2000 45 16+4 SExsS 4
0000 SE 4
7. Vili | 0400 21 16-48 SExs 3
0730 727 12° 09/ 30” ahh uly 6 14:88 SSE 3
1200 Callao WSW I-3
1600 SW 2
2000 = )
0000 = )
20. viii | 0400 Callao — Co)
0806 728 12° 09’ 30” Gif axe 6 15°73 S.Westerly| 2
0948 729 2 Tle 20m 77° 20° IIS 16°64. S. Westerly 2
1204 730 C2 mnliny Gh Oa 19 17°58 SSW 2
1502 731 L2n 220 77° 40° 34 17°73 SSE 2
1g00 52 17°50
2021 732 2S OF 78° 07’ 65 16°51 Southerly 2-3
0000 72 16-63 Southerly 2
21. Vili | 0230 88 15°97
0300 gu 5593
0330 94 16:08
0400 98 16:03 Southerly 2
o5t5 | 733 | 12°54°30" | 78° 43° 105 15-91 | SE 3
0800 114 17°62 S 2
1250 734 13° 16’ 30” 7Onz70 300 154 17°16 Southerly B
1600 SSE 2-3
2000 17°15 SE 3
2200 17°69
0000 17°13 SE 3
22. Vili | 0200 16-7
0400 17°55 SSE 3-4
0800 1785 SE 4
1200 153 17°51 SE 4
1600 17°59 SE 4
1800 16°43
DISCOVERY REPORTS
APPENDIX IV (cont.)
267
Position ; Wind
Date Ho Station ee Temp. es
1931 = WS Latitude Longitude | “Tig | °C:
S W Direction | Force
22. Vill | 2000 16:67 SE 4-5
0000 177 16-70 SE 5
23. Vili | 0400 192 16°47 SExs 4
0845 | 735 | 17° 47' 77° 36 204 16-71 | SE 4
1200 210 17°6 SE 4
1600 235 17°72 SE 4
2030 7 eb SE 4
0000 260 17°69 SE 4
24. Vill | 0200 | 178
0400 | 275 16:85 | SE fi
0800 2904 16-67 SE 4
1000 305 16°87
1200 16°98 SE 4
1600 331 17°10 SExs 4
1800 327 16:67
2000 314 16:67 S 4
0000 295 16-68 S 4
25.vili | 0450 736 222.37 18" Gls eg). 275 16°35 SxE 4
0800 SSE 3
1200 . 263 16°49 SSE 3
1600 15°93 S 4
2000 245 15°93 SSE 4-5
0000 233 15-41 SSE 4-5
26. viii | 0400 15°3 SSE 4-5
0800 202 15°53 SSE 4
1200 15°89 SSE 4
1600 175 15°42 SxE 4
1800 15°37
2000 159 14°77 SxW 4-5
2200 15°24
0000 ; 14:90 S 5-6
27. Vili | O107 737 Pipe Py 73° 40° 136 14°58 SSE 5
0400 : 15"00 SxE 4-5
0600 14°95
0820 14°49 SxE 4
1000 98 13°93
1200 13°82 SxE 4
1600 13°9 Southerly 4
2000 69 13°55 SsWxs 4
0000 45 13°84 SSW 4-5
28. viii | 0400 35 13°55 SxW 3-4
0600 13°90
0800 32 12°28 SxW 3
1000 13°20
1200 31° 19’ GPa ui 23 13°40 Sx W 3
1600 14 13°45 Sx W 4-5
1800 8-5 12°97
1930 738 32° 04’ 30” 7 3 61 073 12°] S) 6 |
268 DISCOVERY REPORTS
APPENDIX IV (cont.)
Position :
. Wind
Date Hour Station z = es Temp.
1931 WS Latitude Longitude anvils “(Ce
WwW Direction | Force
28. vill | 2208 739 32° 05, i wAe Om g:0 12°81 S 6
0000 S 6
29. Vili | 0400 ? 16 12°96 5 6-7
0800 S 6-7
1200 S x W 4-5
1600 Valparaiso SSE I
2000 SE xE I
0000 Light airs fo)
ahix 0400 Valparaiso ExN I-3
0800 ExN i2
1200 Southerly 3
1600 SSW 4
2000 740 33° 50° Gp Bay 18 12°08 SW xs 4
0000 18 12°63 SxW 4
4. 1x 0400 22 12°52 SSW 4
0800 23 12°51 S 4
1200 B55 th On 73° 08’ 30” 23 12°13 SSW 4
1600 21 12-04 SSW 4-5
2000 741 36° 00° TP ily! aay" 25 11-95 SW 4
0000 20 11°65 Southerly 3
5. ix 0400 15 11°85 SSW 3
0800 4 11°20 = °
1200 37° 43 73° 45° 6 II‘I4 a o
1600 12-15 II-21 Ww 2
2000 742 38° 22’ 7 aceAley 7-10 Te 27 NNW 2
0000 15 10°95 WNW 1-2
6. ix 0400 23 11-05 Wxs 2-3
0800 6-7 10°54 Westerly 2-3
1200 Corral NNW 4
1600 NW I
2000 NW 1-2
0000 N I
8. ix 0400 Corral ENE I-2
0800 SE 3-4
1200 40° 03/ 30” 73° 49’ 5 10°13 Southerly 4
1600 8 10°05 Southerly 4
2000 | 743 | 41°05’ 74° 05° pI 9°9 SSW 3
0000 16-17 10°16 S. Easterly | 3-5
g. ix 0400 18 9:90 SE 4-5
0800 24 9°75 SE 4
1200 42° 56’ 30" | 74° 49’ 229 9°58 | SE 4-5
1600 ? 35 9°42 SE 5
2000 | 744 | 43°40'30" | 75°07'30" | 243 9°34 | SE 5
0000 ? 40 9°15 SE 5
10. ix 0400 ? 38 8-84 SExE 5-6
0800 ? 44 7°70 SExE 5
1200 45° 29’ 75° 08" 2 24 8-67 Easterly 5
DISCOVERY REPORTS
APPENDIX IV (cont.)
269
Position : Wind
Date eae Station a ean Temp. a
1931 ig Ws Latitude Longitude para °C,
S W Direction | Force
10. ix 1600 ? 19 8-75 Variable 2
2000 | 745 | 46° 41’ 75° 45° 24 8-45 | SSE 3
0000 7 8-25 SExS 2
iii sb 0400 9 7°91 “= I
0800 Patagonian 0°5—2°0 6-12 SE 2
Channels
1200 SE 2
270 DISCOVERY REPORTS
APPENDIX V
Mean wind vectors (plotted in Fig. 4)
R.R.S. ‘William Scoresby’ | Chilean Meteorological Stations
Mean of observations within a period
Teves Zone > 50 m. offshore Zone <50 m. offshore of 14 days prior to ship’s reaching
os Date same latitude
ING! Mean vector No. Mean vector Position No. Mean vector
of of of of
obs. | Direction| m.p.h. obs. | Direction | m.p.h station obs. | Direction | m.p.h.
46-48 10. V. 31 3 S 20° E 6°33
44-46 2 S 30° E II I S 225 E 21 Aysen 8 SW 2 0°25
42-44 Tlevey 3x 3 S$'77° E 14 I E 15 Huafo II S 21° W 72
40-42 12. V. 31 3 S 68° E 18-7
38-40 12-15. Vv. 31 18 S$ 67°E 5°8 Corral 15 S 82° E 3
Mocha I. 16 S7° W 10
36-38 15-18. v. 31 14 | S 120k o'5 Lebu 12 S) 17°5
Talcahuano itp |) Siac 13) 3°6
34-36 18-20. V. 31 6 | S38°E 5°83 22 | N28°E 4°4 Constitution | 14 | N55° E 18
32-34 | 21-28. v. 31 49 S 46° E 03} Valparaiso 2. S 20° 0°38
29. V. 31 6 S2°E 12°1
30-32 4 S2°E 24°25
30-31. V. 31 4 Ss 75
28-30 | 31. v.31 23. | N 62° W 1°3 Coquimbo 14 NS ey I
4. V1. 31
26-28 | 4-7. vi. 31 4 S 3° W 6°5 16 N 39° E 0°69 Caldera 15 S 80° E 2°26
24-26 4 Si4ackE I1'5 Taltal 14 N 45° E 0°64
22-24 8-9. Vi. 31 14 S4°E 12°7
10. Vi. 31 7 N1°E 61
10-16. vi. 31 36* | N 47° W 072 | Antofagasta 21 S73°E 18
20-22 17-18. Vi. 31 10 S 74° W 1°8 Iquique 14 S 71° W Ls
18-20 18-20. Vi. 31 10 S5° W 23 Arica 17 N 89° E I
16-18 20-21. Vi. 31 6 S$ 81° E 6°17
23-24. Vi. 31 II $47°E 20°5
14-16 | 24. vi. 31 3 | S53°E 14°7 16 | S48°E 14'5
12-14 | 25-26. vi. 31 10 | S57°W 6-2
26. vi. 31 30T | Sg’ E 37
I. Vil. 31 ;
I-3. Vii. 31 6 Wis44cE 16°7 8 S372 58 13°7
3-8. vil. 31 30 S 20° E Bee.
12. Vil. 31 Dl lSi230 1B; 10
12-15. Vii. 31 egy || Syrue 10: 3°05
10-12 8-9. vii. 31 6 S 28° E 6-6
11-12. Vii. 31 | Sep ls 10°5
15-16. Vii. 31 3 S 23° W 8-3 2 S 50° W 4
8-10 | 9-11. Vii. 31 2 $35. E 8-5 is) |) Spzige 13. 371
16-17. Vii. 31 Fh 5 302 13°3
6-8 17-21. Vii. 31 8 S$3r° E 12°13 Ae) || A521; 61
4-6 21-31. Vii. 31 20 | S49°E 6-1 25 S1°W 14°4
26§ | S15°E 11-9
2-3. Vill. 31 10 5S 28°E 15°3
2-4 31. Vil. 31 II 56° W 14°9 5 S 16° W 9°6
2. Vill. 31
6-8 3-4. Vill. 31 8 S39° E 23°4
8-10 | 4-5. viii. 31 8 | S48°E 21°6
10-12 5-7. Vili. 31 6 S$ 43° E 19 3 S 38° E 13°3
12-14 | 7-20. Vili. 31 77t | Sg E 1'7
20-21. Vili. 31 9 | S23°E 2, 4 |S24°W 45
14-16 | 22. Viii. 31 Aa S415 14
16-18 22-23. Vili. 31 5 S42°E 17
18-20 | 23-24. Vili. 31 4 |S45°E 15 Arica GP | 38; 0°57
20-22 | 24. Vili. 31 Q | Sages 14 Iquique 16 | S50° W O5
DISCOVERY REPORTS 271
APPENDIX V (cont.)
R.R.S. ‘William Scoresby’ Chilean Meteorological Stations
Mean of observations within a period
Tagende Zone > 50 m. offshore Zone > 50 m. offshore of 14 days prior to ship’s reaching
2g Date same latitude
No. Mean vector No. Mean vector Position No. Mean vector
of of of of
obs. | Direction] m.p.h. | PS: | Direction | m.p.h. station obs. | Direction | m.p.h.
22-24 | 25. Vili. 31 5 S15°E 13°4 Antofagasta 16 S 50° E 27
24-26 | 25-26. Vili. 31 4 12305 22 Taltal 15 N 60° E 273)
26-28 26-27. Vili. 31 6 S8°E 18-1 Caldera 15 N 72° E 22
28-30 | 27. Vili. 31 3 S 8° W 14°1 I S 23° W 18 Coquimbo 17 N75°E o's
30-32 | 28. vill. 31 4 |S11°W 12°5
32-34 | 28. viii. 31 7 S 4° W 24°7
3e1X. 31
31l| | S28°E o'7 Valparaiso 20 S 82°E o-7
34-36 | 3-4. ix. 31 5 S 16° W 15"4 Constitution 7 S 45° W 1°7
36-38 | 4-5. ix. 31 6 | S33°W 5°8 Lebu LON ESS me, GG}
Talcahuano 16 S 4° W 370
38-40 5-8. ix. 31 16 N 39° W 2 Mocha I. 14 S25°W 76
Corral I WwW 5
40-42 | 8-0. ix. 31 5 S17°E 13
42-44 | 9. ix. 31 5 S45°E 19'2 Huafo I. II S 87° W 3°3
44-46 TOs Ix ar 3 S 67° W 21°3 Aysen 5 N 45° W 0-6
46-48 IO-II. ix. 31 2 S 26°E 7:0
* Antofagasta Harbour. + Callao. t Callao, WS 684. § Talara. || Valparaiso.
The original observations made on board R.R.S. ‘William Scoresby’ are given in Appendix IV. Those of the Chilean stations
are published in the Santiago de Chile Daily Weather Reports.
272 DISCOVERY REPORTS
APPENDIX VI
Mean surface temperatures (plotted in Fig. 34)
Mean surface temperature at different distances from the coast *
o-2 271-5 5°I-10 10°I—20 20°I-50 50°I-100 100°I—200
D Lat. miles miles miles miles miles miles miles
ate 2g
1931 FS
No. | Mean | No. | Mean | No. | Mean | No. | Mean | No. | Mean | No. | Mean | No. | Mean
of temp. of temp. of temp. of temp. of temp. of temp. of temp.
obs. “Ce obs. aC: obs. “Cz obs. ECs obs. miGs obs. Cs, obs. 4G
10. Vv. 46 I 11-7
II. Vv 44 I 12:0
Il.v 2 I 12°73
12.V 41 I 12°66
I5.V 39 I 98 I I1‘22
38 I II‘19 I 10°67
37 I 12°18
16. Vv 36 2 11°45
18.v 35 3 II*54 2 11°84 I 11°62 4 12°3 2 13°61
20. V 34 2 12°63
2I.V 33 I 12°81
28.v 32 I 14:02t 2 13‘91 2 13°95 3 14:07T{| 6 14'91}{| 10 16°15
30. Vv 31 I 13°89 I 14 4 14°35
3I.V 30 | I 13°05 I 15°75
oi e 29 2 14°25 2 14°53 2 14°29 3 14°33
3. Vi 28 I 15°2 I 14°41
4-5. Vi 27 2 13°27 I 14°20 I 14°88 2 15°5 3 16°51 I 16°61
6-7. vi 26 I 15°70 2 16°36
7. Vi 25 Gi 14°46 19 16
7. Vi 24 5 16°43 8 16°29
7-16. vi 23 8 14°47 19 14°82 20 16°26 4 15°97 8 17°26
16. vi 22 GF 15°68 5 15°79 4 15°98 3 16°32
16. vi 21 2 16°65
17. Vi 20 I 15°52 3 16°4 2 17°41
18. vi 19 I 16°3 2 15°83 I 18°59 I 18°45
19. Vi 18 3 1715 2 18 3 18°16 3 18-78
20. Vi 17 4 15°93 8 16°62
20. Vi 16 I 14°79 I 15°12 2 15°12 4 15°69
21-23. Vi 15-16] 4 14°04 I 14°19 I 14°5 I 14°43 8 15°22 9 17°39 6 Ig'l4
25. Vi 14 I 15°38 3 15°14
25. Vi 13 I 1g'l I 17°6 I 16°59
aa 12 I 168 I 16°65 13 17°15 2 17°62 6 18-87 6 18-16 I 18°39
8-15. vii II I 17°32 5 18-69 6 19°6
9-16. vil 10 I 19°69 3 19°97 5 20°04
Q-17. Vii 9 3} 20°47 2 20°28 2 20°52
9-17. Vil 8 2 16°35 D 16°13 7 17°05 4 17°34 8 18-268 7] Ig'I2
17-18. vii 7 2 18-20 3 18°73 4 19°38
19-20. Vii 6 5 17°74 3 17°78 4 17°97
3 vai 5 3 16°95 2 17°19 I 18-26 I 18-49 5 18°29 4 18-22 20 18:92
s hers 4 2|| | 22-sril| 2ll| 2r-4goll tll | 21°34|! | 9 19°25 22 18:03 2 18:94 15 19°28
oie ve 3 2 20°42 2 21°14 5 19°63
2. Vill
31. Vii—
Toa 2 I 24°3 I 24°43 2 24°31 6 23°85 10 22°03
* Mean temperatures in the 200-500 mile zone:
Pep varell) 3 yO
A, el 5° S (2 obs.) 20°38 : (Cr
3. viii 6° S (5 obs.) 19°73° C.
3. viii 7° S (6 obs.) 19:89° C.
+ These data have not been plotted in Fig. 34.
§ This datum has been erroneously plotted in Fig. 34 as 16°77.
|| ‘These data do not include observations off Talara: they are based on observations off Capo Blanco only, and represent tem-
peratures in the tongue of the Equatorial Counter-current.
Note. The time interval between observations that have been averaged, does not exceed 20 days.
}{ Include observations not given in Appendix IV.
INDEX
Acosta, J. de, 111
Aguaje, 110, 229-33
Anchovy, 176
Antarctic intermediate water, 114, 162
Anticyclonic swirl, 192-4, 208
shift in position of, 209-10
Aspiration by surface current, 210, 213
Atkins, W. R. G., 121, 202, 218
Bahia Herradura (Figs. 9, 28), 129, 144
Berghaus, H., 112, 113, 194
Betagh, W., 111, 189
Bougainville, H. Y. P. P. de, 112, 195
Boundaries of the currents:
of Antarctic intermediate water, 162
of Peru Coastal Current, northern, 134, 156-9,
228; southern, 226-7; western, 223-6
of return current, 162
of sub-Antarctic water, 162
Bowman, I., 124, 229
Buchanan, J. Y., 173, 192, 195, 221
Cabbeling, 140
Callao Painter, 110, 229
Cape Horn Current, 226, 227
‘Carnegie’, 114
Centres of upwelling, 214-15
Cephalorhynchus commersoni, 176
Cetacea, 176
Climate, 109-11, 124, 229
interrelation with current, 156, 159, 206, 227
seasonal changes of, 206, 227
Coastal upwelling, 196
Coast-line direction, effect on upwelling, 202
Coker, R. E., 189, 197, 213
Collosphaera, 174
Colour of the current, 173, 221
Comparison of conditions on the east and west
coasts, 234
Comparison of normal and abnormal conditions on
the west coast, 229
Conclusions on the results obtained, 189
Convergence:
of Peru Current and Equatorial Counter-current,
156, 228
of warm wedge with coast: at Arica, 203; at
Callao, 209-10; at Guanape Islands, 209; at
Pisco, 194, 232-3
subtropical, 159-61, 226
Cool water:
disappearance of, 213
early theories of origin, 110
origin of, 195
Counter-current:
in-shore: at Antofagasta, 208; at Caldera, 125;
at Capo Blanco, 131; at Lobos Islands, 156
(see also El Nino)
off-shore, 129, 131, 145, 191
Current:
absence of: at Callao, 128-9, 148; at Cape
Carranza, 125; at Pichidanque Bay, 125
and drift of the ship, 125, 189
of compensation, subsurface, 1g0—1
variability of, 190, 215
velocity of, 189-go
Dampier, W., 124
Darwin, C., 109, 112, 156, 175
Deacon, G. E. R., 120, 159, 160, 162
Dinklage, L. E., 112, 190, 195, 210
Divergence: at Antofagasta, 208; at Arica, 203;
at Guanape Islands, 209 ; at northern Peru, 228
Dosidicus gigas, 177, 233
Drift records, 120-1, 125, 128
Earth’s rotation, influence of: at Antofagasta, 144,
208; at Guanape Islands, 209
Eddies, cyclonic: at Antofagasta, 208, 213; at
Caldera, 141; at Capo Blanco, 191; at Lobos
Islands, 156, 164, 220
Eddies and organic production, 211, 220
Ekman, V. W., 202, 208, 210
El Nino, 110, 158, 205, 229, 234
Engraulis ringens, 176
Equatorial Counter-current, 110, 115, 156, 159, 162,
166, 169
fauna of, 176
Euglenids, 232
Euphausia vallentini, 177
Euphausians, 173, 221-2
Fish, 111, 134, 176, 234
FitzRoy, R., 112, 222
Flagellates, 173, 232
Frictional influence, depth of, 204, 211
Galapagos Islands, 156
Garua, 222-3, 229
Globicephalus, 176
Guano, 109-10, 176, 177, 216
Hardy, A. C., 121, 179, 218, 220, 221, 234
Elarteyea)s 1205 2224232.8233
Hoffmann, P., 195, 226
Hollmann, Kapt. z. See, 195
Humboldt, A. de, 110, 112, 113, 195
Humboldt Current, 113, 226
274
Isotherms, surface (Figs. 16, 17), 136, 137, 193
Johnstone, A. K., 113
Juan Fernandez (Fig. 4), 123
Kriimmel, O., 112
Lartigue, J., 190
Latitude, effect on upwelling, 212
Laurie, A. H., 117, 180
Lavalle, J. A., 194, 216, 232
Life in the Current, 175
Lobos Islands (Fig. 12), 132
Matthews, D. J., 117, 120
Maury, M. F., 112
McEwen, G. F., 196, 203, 204, 212
Medusae, 173
Mentor’s Gegen Drift, 113, 194
Merluccius gayi, 234
Mesodinium, 233
Methods, 120
Mixing, vertical: at Antofagasta, 144, 206, 213; at
Caldera, 140, 213; at Callao, 172; at northern
Peru, 152
Monsoon: in Chile, 227; in Peru, 206
Mossman, R. C., 124, 226
Murphy, R. C., 176, 197, 203-5, 215, 216, 226
Nino, see El Nino
Nomenclature of currents, 109, 113, 114, 223
Orbigny, A. d’, 177, 233
Palominos Island (Fig. 10), 130
coloured water, 129, 174
control station, 169, 209
current, 129
temperature, 169
Perez-Rosales, V., 226
Peru Coastal Current:
breadth, 151-3, 156, 224-5
boundaries, g.v., 114-16, 223
colours, 178, 221-2
depth, 112
general description, 109, 113-14
Peru Current, origin, 195, 196, 226
Peru Oceanic Current, 114, 223
Phalacrocorax bougainvillit, 174, 176
Phosphate and temperature, 182-3
Phosphate consumption, 184-9
Phosphate content, 180, 218
Phytoplankton and colour of current, 178
Phytoplankton distribution, 181
Piquero, 176
Pisco (Fig. 11), 130
Plankton, 177
Planktoniella, 188
Punta Tetas (Figs. 9, 28), 129, 144
Raimondi, D. A., 194, 222, 229
INDEX
Ray, R. C., 192
References, list of, 241
Regional fertility, 219-20
Return Current, 140, 162-4, 194
Ridgeway, R., 251
Salinity, 159
San Lorenzo Island (Fig. 10), 130
Sandstrém, W. J., 140, 145, 202
Schott, G., 112, 156, 160, 190-215, 225, 226, 228-9
Schweigger, E. H., 112, 113
Sea-bottom contour, effect on upwelling, 203
Seals, 176
Seasonal changes, 156, 169, 206, 227
Seiche, 212
Sharks, 176
Sinking of newly mixed water, 140, 213
Somerville, B. 'T., 192, 226
South Equatorial Current, 156, 224, 226, 228
Squids, 176-7, 233-4
Stiglich, G., 191, 194, 222, 230
Sub-Antarctic water, 159, 161-3
Subsidence, 213-14
at Antofagasta, 143-5, 208; at Callao, 148; at
Cape Carranza, 135; at Guanape Islands,
151-6, 209
Sub-tropical water, 159, 161-2, 166, 169
Sula nebouxi, 176
Sula variegata, 176
Summary, 235
Sverdrup, H. U., 112-15, 159, 197
Swirl in surface current, 192
Systrophe, 222
‘Temperature, 134
Tessan, U. de, 112, 195
Terral, 124
Torrico, R., 117
Track chart (Figs. 2, 3), 118, 119
Trade wind, 124, 229
Tropical water, 115, 161
Upwelling :
area coming under the influence of, 115-16,
195-6, 224
breadth of zone of, 202
centres of, 214-15
depth affected by, 197-8, 200-1
effect of bottom contour on, 203
effect of coast-line direction on, 202
effect of latitude on, 211
effect of seiche on, 212
effect of wind on, distant: at Arica, 145; at Callao,
210-11; at Guanape Islands, 210-11; at Pichi-
danque Bay, 140
effect of wind on, local, northerly: at Antofagasta,
142; in the Caldera neighbourhood, 140
off-shore: at Antofagasta, 144
on-shore: at Callao, 148; at Guafape Islands,
152; at Pisco, 210, 232-3
INDEX
Upwelling (cont.):
effect of wind on, local:
southerly: at Guanape Islands, 152; at Pichi-
danque Bay, 140; at northern Peru, 152; at
San Juan, 148
in Gulf of Panama, 206
of return current: at Antofagasta, Cape Carranza,
San Juan, 162-3
of sub-Antarctic water: at Arica, Caldera, Cape
Carranza, Pichidanque Bay, 162-3
of subtropical water: at Callao, Capo Blanco,
Guanape Islands, Lobos Islands, Punta Aguja,
164-9, 200
water masses involved in, 199-200
Vallaux, C., 112, 226
Virazon, 124
275
Walter, R., 111
Warm wedge of surface water, 191-2
biology, 134, 188
phosphate, 186, 188
salinity, 161
temperature, 134, 148-51, 156-8, 171
Water masses associated with Peru Current, 159-62
West Wind Drift, 226
Whales, 109, 176, 177
Wilhelm, O., 177, 234
Wind, effect on water movements, see Upwelling
Wind records, 123, 252-71
Witte, E., 112, 140; 195,213
Zarate, A. de, 110
t periage & j TEES
ylovitsqeny Jick Yano desys Gils
BS As ie Pe errr cee eet tt
S20 olge Sty hs (8595
B trea. oS % Sk
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tr mo
i cliAD....7 S17.
ESeeyooT ott .c-.9fT
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4p ser
Exot ae wer: Gee
PLATE XIV
Photographs illustrating scenery and climate in South America.
Figs. 1 and 2, taken in lat. 10-12° S, and Figs. 3 and 4, taken in lat.
49-53° S, illustrate the reversed character of the scenery west and east of
the Cordillera. Figs. 1 and 3 of the west coast fall respectively within
the South Pacific high pressure area and the region of the westerly
winds, and correspond to the tracts of the Peru Current and the Cape
Horn Current.
Fig. 1. Chicla in the Peruvian Sierra (lat. 1o-12° S). 10. viii. 31.
Fig. 2. The Peruvian Montafia near San Ramon (lat. 10-12° S) showing
forests of the Amazon basin.
Fig. 3. Field Anchorage, Straits of Magellan (lat. 53° S). 15. ix. 31.
Fig. 4. Monte Kochaik, Argentina (lat. 49° S). 19. ii. 03.
XIV
PEATE
XI
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DISCOVERY R
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oud qtemygso4' 7 HY
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REPORTS
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ze oT Ae an asin! hips s¢ alt 10 wilstiony | besaqesbi¥l ah ord
OF WE aed smodasil oneusl tee
zr
7 Sa
PLATE XV
Fig. 1. Cormorants (Phalacrocorax bougainvilli‘), locally known as
Guanay; in Callao harbour. 16. viii. 31.
Fig. 2. Cormorants in foreground and pelicans (Pelecanus thagus),
locally known as Alcatraz; at Antofagasta. 13. vi. 31.
Fig. 3. Gannets (Sula nebouxi and S. variegata) known locally by the
name of Camanay and Piquero; on Lobos de Tierra. 20. vii. 31.
Fig. 4. Widespread mortality of the squid Dosidicus gigas in Talca-
huano harbour. 15. iv. 30.
DISCOVERY REPORTS VOL. Xill PLATE XV
ERG phot
ERG. phot
—
EEE: al Te
SS
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= 4
ét \
ar
=
a ee
Ottmar Wilhelm phot
GUANO BIRDS AND SQUIDS OF THE PERU COASTAL CURRENT
'
re ses ay “Prry —o arayt
MoOOVERY REPORTS VOL. XID PLATE X\
-_ =
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PLATE XVI
Coloured figures illustrating the appearance of the sea, executed by the
author during the survey.
The blue washes in Figs. 5, 13 and 15 illustrate the appearance of the
open ocean in sunny conditions, the indigo, Figs. 12 and 14 when
overcast : these sketches were made at more than 30 miles from the coast
(see below). The green washes, Figs. 1, 4, 9 and 10 may be looked upon
as normal for the in-shore water: Figs. 2, 3 and 8 as intermediate between
the blue and green. The reddish yellow Figs. 6, 7 and 11 found re-
spectively at Pisco, Callao and the Guafiape Islands are abnormal
colorations (see pp. 221-2).
The colours (Figs. 3, 4 and 14 excepted) represent transmitted light
and were obtained by looking down into the water under the overhang
of the ship’s stern where interference from reflected light is mostly
eliminated. In Fig. 12 a swirl of air bubbles produced by the screw is
indicated. The importance of avoiding sky reflections is shown in Fig. 4
in which surface reflection was blue but the colour of the water in wave
shadows was green: compare also Figs. 2 and 12 with the corresponding
appearance of the sea surface in Figs. 3 and 14.
A Table showing date, hour, position and nomenclature of the original
observations illustrated in Plate XVI is given in Appendix III.
Miles from Miles from
Fig. Locality land Fig. Locality land
tT 4405 63 g Salaverry 10
PN ASS: 10 to. ©=>- Salaverry
Bye ANS 10 11 Guanape Islands 8
4 Antofagasta I 12) Os 63
5 Antofagasta 46 noe PAS) 255
6 Pisco 2 14 1079 63
7 Callao 6-15 re) hrs BZ
8 Callao 6
DISCOVERY REPORTS VOL. XII PLATE XVI
10 I I2
COLORATION OF SEA WATER IN THE PERU CURRENT
ms
j
:
4
sae FS ae Saka :
THE CAMBRIDGE
_ UNIVERSITY
EWEPRESS hy
vs ae
DISCOVERY
REPORTS
Vol. XIII, pp. 277-384
Issued by the Discovery Committee, Colonial Office, London
on behalf of the Government of the Dependencies of the Falkland Islands
| RHINCALANUS GIGAS (BRADY)
A COPEPOD OF THE SOUTHERN
MACROPLANKTON
by
F. D. Ommanney, Ph.D. (Lond.), A.R.C.S.
SMa AS)
VA r sau ON
(is NOV 22 1936
\ eran a8
CAMBRIDGE
AT THE UNIVERSITY PRESS
1936
Price fifteen shillings net
2 by
ae ae
[Discovery Reports. Vol. XIII, pp. 277-384, October, 1936.|
iw PNCALANUS GIGAS (BRADY)
PaCORELOD OF THE SOUTHERN
MWMACKOPLANK TON
By
F. D. OMMANNEY, Pu.D.(Lond.), A.R.C.S.
CONTENTS
IntreductionS iy ey ce ew on ese cu ern e-0 OP E2271. 0)
Methods 280
Hydrology of the area 286
Previous work . 293
Distribution of Rhincalanus gigas 293
Horizontal distribution, season 1931-2:
Falkland Sector, November to mid-January 294
Falkland Sector, mid-January to mid-February 297
Around the Antarctic Continent, April to October 299
Bathymetrical distribution, seasons 1931-2 and 1932-3:
Falkland Sector Kou!
Weddell Sea . 304
Horizontal distribution, season 1932-3:
Falkland Sector, October to December 308
Falkland Sector, February to March Bi
Vertical range and diurnal variation . 314
Summary 325
Life history : é 316
Approach of the spawning eel 316
Composition of the stock of Rhincalanus gigas é 322
Drake Passage and South Atlantic Ocean, November s 1931 323
Scotia Sea and South Georgia, December 1931 326
South Atlantic Ocean, east of South wees mid- December 1931 to
mid-January 1932 ; ‘ 326
Weddell Sea, mid-December 1931 to Namie Janney, 1932 . 330
Weddell Sea and Eastern Scotia Sea, end of January 1932 332
Falkland Islands to South Georgia, mid-February 1932 334
Summary, Falkland Sector, season 1931-2 336
South Indian Ocean and Australian Sector, winter done April
May and June 1932 . a, OR8
Summary, South Indian Oten ied Aare Becton: AGites
months 1932 . : 340
Drake Passage, October to sane: November. 1932 . 341
Scotia Sea and South Atlantic Ocean, mid-November to mid- December
1932 . : 342
Drake Passage, anny ayaa 1933 - pe 345
Falkland Islands to South Georgia, rere 1933 346
Weddell Sea, March 1933 349
Summary, Falkland Sector, season 1932-3 351
Comparison of seasons 1931-2 and 1932-3, Balgland Sector 352
Discussion . 354
General Summary . 358
List of Literature . 360
Tables I-VI
Min NEALANUS GIGAs (BRADY)
Pac OrerOD sO THE, SO UDEE RN
MACROPLANKTON
By F. D. Ommanney, Pu.D.(Lond.), A.R.C:S.
(Text-figs. 1-29)
INTRODUCTION
Dp. the second Antarctic commission (1931-3) of the R.R.S. ‘Discovery II’
the programme carried out involved two extensive plankton surveys of the waters
of the Falkland Sector, one between November 1931 and January 1932 and a second
between October 1932 and March 1933. During each of these surveys the same general
plan was adopted. North to south lines of stations were taken across the Sector, extend-
ing from sub-Antarctic latitudes as far south as the edge of the pack-ice. These north
to south lines were connected by east to west lines along the edge of the ice. A number
of routine stations was also taken in particular areas where observations have been made
repeatedly by the Discovery Committee’s ships during several seasons—such as South
Georgia, the Bransfield Strait and the South Atlantic Ocean between South Georgia
and the Falkland Islands. During the winter months of 1932 these north to south lines
were extended around the Antarctic Continent and a circumnavigation of the southern
hemisphere was made, the ship leaving Cape Town in early April 1932 and arriving
at the Magellan Straits in early October 1932.
At nearly every one of the stations taken during these cruises, both in the Falkland
Sector and around the Antarctic Continent, oblique towings were made with the 1-m.
stramin net (see Kemp, Hardy and Mackintosh, 1929, p. 184). From these towings a
large collection of macroplankton was obtained and the Copepoda from a selection of
the catches have been analysed. The following report is an attempt to give an account
of the distribution, and an outline of the general life cycle, of one species of macro-
planktonic copepod from among the many species (about fifty in all) which were
frequently encountered in the macroplankton during the cruises.
The species, Rhincalanus gigas (Brady), has been specially selected for investigation
for two reasons. Firstly, it is the dominant copepod throughout a very large area of the
Falkland Sector of the Antarctic, with which the work of the Discovery Committee is
chiefly concerned. In this area it is the dominant organism of the macroplankton,
forming in its region of greatest abundance over 75 per cent, and sometimes over go per
cent, of the total copepod catches. It may be said with some safety, therefore, that the
life history of this species will typify that of the Antarctic macroplanktonic Copepoda
generally, and for this reason a knowledge of its biology is of the greatest importance. ‘The
I-2
280 DISCOVERY REPORTS
second reason for selecting this species for investigation is its large size. The adult is
8-o-g:0 mm. in length, and the young copepodite stages are large enough to be taken
by the stramin net. As a general rule the young stages of nearly all the species of
macroplanktonic copepods are so small that they escape through the meshes of the 1-m.
net. The young copepodites of Rhincalanus gigas, however, in stage 111 and older, were
easily retained and occurred constantly. Stage ii occurred rather less frequently and
nauplii and stage i occurred only, presumably, when present in great abundance in the
water. Some idea at least of the course of events during the life cycle of the species can
therefore be obtained from the catches taken with the towed 1-m. net.
The author is deeply indebted to Mr G. E. R. Deacon and to Mr F. S. Russell,
D.S.C., for much help and criticism. In the many hydrological problems which arose
during the course of this work the advice of Mr Deacon was invaluable.
METHODS
The stations at which the Copepoda from the 1-m. nets were examined during the
seasons 1931-2 and 1932-3 in the Falkland Sector, and during the winter months around
the Antarctic Continent, are shown in Figs. 1 a,b, 2.a,b, and 3 and Tables I a-c.
It will be seen that only a selection of the total stations taken have been dealt with. The
catches were examined from 7o stations in the Falkland Sector in the summer season
November 1931 to February 1932 and 76 during the season October 1932 to March 1933.
During the circumpolar cruise, April to October 1932, the copepod catches were
examined from 108 stations.
Whenever possible, as will be seen from the tables, two towings were made with the
I-m. stramin net, one using the net as a closing net and towing obliquely from as nearly
as possible 250 m. to as nearly as possible roo m., and the other towing as nearly as
possible from too m. to the surface. Both the upper and the lower nets were always fished
for the same length of time at every station: the upper for 20 minutes and the lower
for 30 minutes. ‘Two 70-cm. silk nets were also attached to the warp and towed through
the same depths, one in conjunction with each of the 1-m. nets. This paper, however, is
concerned only with the catches obtained by the latter. All four nets (two 1m. and two
70 cm.) were towed together on the same warp, and the messenger, which closed the
lower nets at about 100 m., was released after the two upper nets (100-0 m.) had been
taken on board. A Kelvin tube, attached to a stream-lined lead, was placed between
the two upper nets to indicate the depth from which they were towed, and a Bourdon
tube depth gauge was shackled to the end of the warp to indicate the depths between
which the lower nets were fished. This instrument also gave some indication of the path
of the nets through the water. (For further details of the nets and apparatus see Kemp,
Hardy and Mackintosh, 1929; Ardley and Mackintosh, 1936.)
It will be seen from 'Tables I a—c and II a—c that the actual depths through which the
nets fished varied constantly and widely from the 100-0 m. and 250-100 m. which were
aimed at in every case. The warp was always hauled in at a constant speed of 10 m. a
minute, and the speed of the ship when towing was kept as nearly as possible at two
Ke SANDWICH *
755+ Is.
Ars
ces v\ 763.
ae
799 °72 7615
BELLINGSHAUSEN x /
4 Oy
Fig. 10.
Charts showing stations taken by the R.R.S. ‘Discovery II’ in the Falkland Sector of the Antarctic in the
season 1931-2. Only those stations have been numbered at which the Copepoda were examined.
a. November 1931 to mid-January 1932. 6. Mid-January 1932 to February 1932.
Fig. 25.
Charts showing stations taken by the R.R.S. ‘Discovery II’ in the Falkland Sector of the Antarctic in the
season 1932-3. Only those stations have been numbered at which the Copepoda were examined.
a. October to December 1932. b. February to March 1933.
283
CAL CONVERGENCE —__
oe
¥ B40- 84) 842 Pr
es
= 687. BBE pes
“a 959, .95
968 gg5\, 96326! gg 958 “95
gg? 966 984. 962 ‘9
West 180° East
Fig. 3. Chart showing stations taken by the R.R.S. ‘Discovery II’ around the Antarctic Continent during
the winter months, February to October 1932. Only those stations have been numbered at which the
Copepoda were examined.
284 DISCOVERY REPORTS
knots. Nevertheless it was never possible to keep the ship’s speed absolutely constant
during any one towing or to be sure that the speed of the ship was exactly the same at
successive towings, and with small variations in the speed the depth of the nets varied
widely—the nets rising towards the surface with increased speed and falling with de-
creased speed. Thus the shallowest surface haul was at St. 735, where the net fished
from 62 to o m., and the deepest was at St. 748, where the net fished from 180 to 0 m.
There were many gradations between these two extremes. ‘The deep net also frequently
fished through depths which varied widely from those aimed at. ‘The following stations
may be quoted as instances of the kind of variation which occurred:
St. 727: 310-170 m. St. 769: 342-150 m.
733: 300-140 m. 776: 356-170 m.
746: 306-124 m. 802: 320- 70 m.
748: 204-138 m. 815: 314-188 m.
757: 320-126 m. 830: 356-140 m.
Similar figures may be found throughout the tables. The question of applying some
correction to these hauls so as to standardize the catches should therefore be given
consideration.
In spite of the somewhat wide variations in the depths at which the surface net
began towing it can be shown diagrammatically (Fig. 4) that the oblique path of the
SURFACE HAUL
<— TRACK OF SHIP STEAMING AT 2 KNOTS (60m. PER MINUTE]= 1200m. APPROX A
100m
1305, APPROX :
is 200m
DEEP HAUL
<— TRACK OF SHIP STEAMING AT 2 KNOTS [60m.PER MINUTE] - 1200m. APPROX A ‘
A TOA.WIRE OUT 500M.
B. CLOSING DEPTH
100m
A + 200m
K
300™
Fig. 4. Diagram illustrating the variations in the length of the oblique tow with variations in the com-
mencing depth of the surface and deep hauls and in the closing depth of the deep net.
net to the surface was in reality not widely different at every haul. In Fig. 4 a number
of surface hauls have been plotted which begin at depths varying from 50 to 180 m., the
widest limits of error met with in the surface towings under consideration. The com-
mencing depth aimed at in every case was 100 m., which, as the diagram shows, gives
a towing of approximately 1375 m., assuming the path of the net to the surface to be a
perfectly straight oblique line. A haul with a commencing depth of 50 m., however,
gives a towing 1395 m. in length (approximately). ‘This is only 20 m. in excess of the
length aimed at (1375 m.), and in view of the length of the tow and of the circumstances
RHINCALANUS GIGAS 285
and conditions under which the hauls were necessarily carried out, it is an almost
negligible error. Greater commencing depths than 100 m. give towings varying somewhat
more widely from the length aimed at. A commencing depth of 180 m. gives an oblique
towing of about 1305 m., 70 m. too short. Even this, however, represents an error of
only 5-3 per cent, and it was seldom that the surface net reached so great a depth as
180 m. The commencing depth was more usually between 100 and 150 m.—the latter
depth giving a towing of about 1340 m., an error of only 2-2 per cent.
The deep hauls, when plotted in the same way, show greater errors, which arise
mainly from the varying depths at which the net closes. The depth aimed at, 250—
100 m., gives a towing about ggo m. in length, and it may be seen from Fig. 4 that such
a haul as that made at St. 802, 320-70 m., gives a tow of about 1275 m., a difference
from that aimed at of 285 m. A towing such as that at St. 776, however (356-170 m.),
gives a haul of about 835 m. only, a difference from that aimed at of 155 m.
Nevertheless, in spite of the wide variations in the depths through which the deep
net was towed, it was decided to make no attempt to apply a standardizing correction
to the catches, firstly because it is impossible to find any simple or constant correction
to apply, and secondly because the nets used cannot be regarded as instruments which
give a quantitative estimate of the plankton. The results obtained with them must be
looked upon as strictly qualitative, and the numbers in the catches must be taken to
indicate only relative abundance or relative scarcity.
The path of the net actually traced out during an oblique towing is never under any
circumstances a perfectly straight oblique line, since, as already explained, the net rises
and falls with variations in the speed of the ship, which can never be kept absolutely
constant. Again, very many factors introduce inaccuracies into the results obtained with
towed nets of this description, such as the local swarming of the plankton, variations
in the depth of the plankton with the weather, and the possibility of the nets fishing
to some extent when being paid out or handled at the surface and so on. Hardy and
Gunther (1935) have drawn attention to this general aspect of plankton investigation
(p. 27) and it may be once more emphasized here. “We are in this work concerning
ourselves only with big differences; the very nature of the distribution of the plankton
we are studying and the necessary limitations to our methods in the field will not allow
us to attempt the establishment of small differences. When we are comparing one
region represented by 5000 Corethron with another represented by 562,000, what does
it matter if that 5000 is really 7500 or 2500, or again if the 562,000 1s really 281,000 or
743,000?” Similarly with Rhincalanus gigas, if we are comparing one region represented
by 15,300 R. gigas with one represented by 5730 it makes no difference to the final
picture of the distribution of the species if the former number is really 13,250 or 18,470,
and the latter number 7250 or 4320. So that even if a standardizing correction could be
applied to the hauls the labour of applying it would certainly not be repaid.
As will presently be seen (pp. 286~7) we are in this report concerned with two layers of
water in the area studied, an upper and a lower one. The boundary between these two
layers of water is usually only known to the nearest 50 or 100 m., so that the length of
D XIII 2
286 DISCOVERY REPORTS
the path of the deep net in the upper and in the lower layer is only very approximately
known. The proportion of the catch, therefore, which properly belongs to each layer of
water cannot be ascertained. All that can ever be said is that part at any rate of the catch
in the deep net belongs to the lower layer, except at certain stations (marked with two
asterisks in Table II a—c, p. 369) where the lower layer approaches the surface to such
an extent that the whole of the path of the deep net lies within it. Similarly the catch in
the upper net either belongs wholly to the upper of the two water layers under
consideration, or else, when the boundary between the layers lies near the surface as
at the stations marked with two asterisks in Table II a-c, it must contain a percentage
which belongs to the lower layer. The variation in the depth of the boundary between
these two layers and the mixing which always takes place across it are, therefore, factors
which introduce large but unknown variations into the catches and which make it useless
to attempt any exact interpretation of the figures.
Little need be said about the methods employed in the laboratory during this work.
In every case the samples were fixed and preserved in 10 per cent formalin and were
analysed by direct inspection and counting, using a binocular microscope and a Petri
dish, in which the sample was spread out. When the samples were too bulky for com-
plete examination they were fractioned over a card marked in eighths or tenths and
a fraction only of the sample was examined. Very often, after a fraction of the whole
sample had been examined, it was necessary to take yet another fraction of the Copepoda
left after the other organisms had been counted, so that fractions of a fiftieth or a
hundredth of the total Copepoda are not uncommon in the analyses. This method of
analysis is, again, only approximately accurate when fractions are examined, and the
smaller the fraction of the total sample examined the greater the error in the analysis.
Many of the samples were analysed on board the ‘ Discovery II’ during the cruises,
but a large number of the copepod analyses were repeated on shore.
HYDROLOGY Ob Wir ARE
It is not necessary here to enter into a detailed description of the hydrology of the area
covered by these cruises. For the hydrology of both the Falkland Sector of the Antarctic
and of the Southern Ocean reference should be made to the accounts published by
Deacon (1933 and 1936). It is perhaps desirable, however, to give the very briefest
account possible of the hydrological conditions in the area traversed, so far as they are
likely to affect the catches with which this paper is concerned.
Antarctic Seas generally are characterized by a cold, poorly saline layer at the surface
known as Antarctic surface water. It owes its low temperature and salinity to the cold
Antarctic climate and to the melting of pack-ice, and it has an average depth of about
200m. Antarctic surface water streams away from the Antarctic Continent and its
surrounding pack-ice in a northerly and easterly direction and becomes part of the
general eastward movement around the Southern Hemisphere known as the West Wind
ee error
RHINCALANUS GIGAS 287
Drift. Where it meets with warmer, more saline sub-Antarctic water the Antarctic sur-
face water sinks along a well-defined line known as the Antarctic convergence (Deacon,
1933, Pp- 190-3). From one side of the Antarctic convergence to the other there is a
pronounced difference in surface temperature which is more marked at some places
than at others. The Antarctic convergence (Figs. 1-3) is thus held to be the boundary
between the Antarctic and sub-Antarctic Zones. Beneath this northward- and eastward-
flowing Antarctic surface layer is a very much thicker layer of warmer water flowing
southwards from the Atlantic, Pacific or Indian Oceans, known as the warm deep water.
‘A certain amount of mixing must always take place between the two layers across the
discontinuity layer which separates them, especially in winter.. .. Warm deep water has
never itself been found at the surface although it has been found with its maximum tem-
perature at a depth of only 100 m.: it is always covered with Antarctic surface water”
(Deacon, 1933, p. 180). Along the Antarctic continental shelf, and in certain other
places, warm deep water wells upwards towards the surface. In the Falkland Sector this
upwelling is most pronounced along the west coast of Graham Land and the South
Shetlands ‘“‘and along that part of the ridge known as the Scotia Arc which joins Join-
ville Island to the South Orkney Islands and the South Sandwich Islands”’ (Deacon,
1933, p- 181).
Thus throughout the whole of the area covered by the present report two layers of
water must be taken into consideration—the northward- and eastward-moving Antarctic
surface water and the southward-moving warm deep water below it. The 1oo-o m. net
was almost always towed entirely in the Antarctic surface layer, but, as Tables II a—c
show, the lower net usually fished partly in the Antarctic surface layer and partly in the
warm deep layer. At a few stations, however, mostly in the positions mentioned above,
that is on the continental shelf or on the Scotia Arc where warm deep water wells up-
ward to the surface, the deep net was towed entirely in the warm deep water. These
stations are marked with two asterisks in Table II a-c. Those marked with one are
stations at which the upper net fished entirely in Antarctic surface water and the lower
net partly in Antarctic surface water and partly in warm deep water. ‘Those which
bear no asterisk are stations at which both nets fished in Antarctic surface water since
the discontinuity layer lay below the range of the hauls. The tables show that at most
of the stations in the northerly part of the Antarctic Zone, where the discontinuity
between the two layers lay deep down, the deep net was worked in Antarctic surface
water. During the circumpolar cruise the deep net was almost always towed partly
in both layers of water, but at certain stations it was wholly in the deep layer. These
stations were situated either on the continental shelf or on the boundary between the
East and West Wind Drift currents shortly to be described, where again warm water
wells upward towards the surface.
In the Falkland Sector water passes through the Drake Passage in an easterly direc-
tion, the West Wind Drift current being here constricted by the peninsula of Graham
Land on the south and by South America on the north. ‘The Antarctic convergence passes
through the Drake Passage (Figs. 1, 2 and 3), and in about 55°S and 49° W it turns north
2-2
288 DISCOVERY REPORTS
between the Falkland Islands and South Georgia. It turns east again in about 53° S and
passes north of South Georgia across the South Atlantic.
North of the Antarctic convergence sub-Antarctic water of the West Wind Drift
passes through the Drake Passage from the Pacific Ocean around the east coast of the
Falkland Islands into the Atlantic Ocean. South of the convergence the water flowing
eastwards through the Drake Passage originates in the Bellingshausen Sea and passes
into the South Atlantic through the western Scotia Sea and around the western end of
the island of South Georgia. North of the island it resumes its more eastward course
between 50 and 55° S. This is really part of the West Wind Drift, but in this report it
will be known as the Bellingshausen Sea current to distinguish it from the West Wind
Drift water north of the convergence.
In the Drake Passage and Scotia Sea the warm deep water flowing southwards pro-
bably originates in the Pacific Ocean, and that in the Atlantic Ocean north and east of
South Georgia originates in the Atlantic (Deacon, 1933, p. 237).
In the Weddell Sea, on the eastern side of the Graham Land peninsula, there is a
cyclonic current system. South of 66° S. and east of 15° E water flows westwards into
the Weddell Sea. It circulates in a clockwise direction along the east coast of Graham
Land and flows out in a north-easterly direction towards the South Sandwich Islands
across the eastern Scotia Sea. This Weddell Sea current is colder and more saline than
the Bellingshausen Sea current and carries pack-ice and numerous icebergs. Where it
meets with the warmer, less saline Bellingshausen Sea current in the Scotia Sea and in
the South Atlantic east of South Georgia it both mixes with it and sinks below it, but its
influence is perceptible in the South Atlantic as far east as longitude 30° E.
A tongue of water of Weddell Sea origin runs north-westwards in the Scotia Sea be-
tween the South Orkney Islands and South Georgia, and another passes in a north-
westerly direction along the east coast of South Georgia. These are visible in the shape of
the isotherms calculated from the average temperature of the surface 100 m. at each
station! (Figs. 5, 6). The bend of the o and 1-o° isotherms westwards in the Scotia Sea
in the season 1931-2 (Fig. 5) and again in the season 1932-3 (Fig. 6) shows where the
tongue of Weddell Sea water projects into the Bellingshausen Sea current. Similar
westward bends in the o and 1-0” isotherms, but particularly in the latter, are discernible
east of South Georgia, where there is another westerly projection of Weddell Sea water
into the Bellingshausen Sea current. A small eddy of Weddell Sea water passes westwards
around Joinville Island and flows into the southern part of the Bransfield Strait
(Fig. 6).
In the Antarctic surface water of the Falkland Sector there are, therefore, two main
masses of water—the Bellingshausen Sea current, passing from the Bellingshausen Sea
into the South Atlantic through the Drake Passage and around the western end of the
island of South Georgia, and the Weddell Sea current, passing north-eastwards from
the Weddell Sea across the Scotia Sea towards the South Sandwich Islands. In the
' It should be noted that temperature, throughout this report, is expressed as the average of the readings
between o and 100 m. The isotherms also are calculated on this basis.
RHINCALANUS GIGAS 289
Scotia Sea south of South Georgia and in the South Atlantic east of South Georgia the
waters of the two origins mix.
Beneath the surface water in the Weddell Sea is a warm deep current flowing west-
wards into the Weddell Sea from the Indian Ocean south of 66° S and east of 15° E.
It follows the clockwise course of the surface water in the Weddell Sea and flows out
as a cold deep current (cooled on its passage around the Weddell Sea) towards the South
Sandwich Islands. ‘As soon as it meets warm deep waters of Pacific or Atlantic origin
it both sinks below them and mixes with them” (Deacon, 1933, p. 229).
Fig. 5. Isotherms (°C.), calculated from the average temperature of the surface 100 m., in the Falkland
Sector of the Antarctic, November 1931 to mid-January 1932.
With regard to the area traversed during the circumpolar cruise outside the Falk-
land Sector, only two hydrological features, in addition to the two layers of water
already described (Antarctic surface water and warm deep water), are of interest to us
in the present report. The first of these is the West Wind Drift which forms a continuous
easterly movement of Antarctic surface water, with a strong northerly component, all
round the Antarctic Continent. The second is the exactly opposite movement which
takes place round the Antarctic Continent in the region of easterly winds south of about
65° S. This current, flowing westwards around the coast of Antarctica, is known as the
East Wind Drift, and it is this current which flows into the Weddell Sea south of 66° S
and out of it again along the east coast of Graham Land as the north-easterly Weddell
Sea current. The boundary between the West Wind and East Wind Drift currents is
AU
ay} Woy poyepNoyeo ‘("d ,) SUIZayJOST “9 “SIZ
000
0 €v:0«
oO8
OLI-\:
6L!- 98:1
vS:l—y
RHINCALANUS GIGAS oF
indicated as a dotted line in Figs. 3 and 11 and is a region of very marked upwelling of
warm deep water towards the surface. These regions of upwelling deep water are of im-
portance, since they have pronounced effects upon the plankton.
In the surface water of each of the two main water masses in the Falkland Sector—
the Weddell Sea current and the Bellingshausen Sea current—it has been found possible
to distinguish four main types of water each having fairly distinctive characters. Figs. 5,
6 and 7 show the isotherms in the Falkland Sector during the seasons 1931-2 and
°0:58 Ko
a2)
Fig. 7. Isotherms (°C.), calculated from the average temperature of the surface 100 m., in the Falkland
Sector of the Antarctic, February, March 1933. (Dotted lines represent the conjectural position of the
isotherms.)
1932-3, based upon the average temperature of the surface hundred metres at each
station. The following four types of water are distinguishable:
(a) Very cold water with a temperature less than — 1°5° C., carrying pack-ice which
is not melting.
(6) Warmer water with a temperature between — 1-5 and — 1-o° C., carrying melting
pack-ice.
(c) Water with a temperature between — 1-0 and o-o° C., in which pack-ice has
recently melted.
(d) Water with a temperature between o-o and 1-o0° C. in the Weddell Sea current and
between 0-0 and 2:0° C. in the Bellingshausen Sea current.
Thus there is established a conception of the ‘‘age”’ of water of various types, since
292 DISCOVERY REPORTS
type (d) will have drifted farther from its source of origin than type (c), and type (c)
than type (d) and so on. Water carrying unmelted pack-ice in the centre of the Weddell
Sea and far south in the Bellingshausen Sea is conceived as being the “ youngest” type
of water. It was met with only to a small extent in the season 1931-2 in the Bellings-
hausen Sea, since the edge of the ice lay to the northward in the Drake Passage in the
spring of that year. The chief value of this classification for the purpose of this report
is that it provides a useful means of distinguishing between the various regions in
which the catches were taken and it will be shown that to a limited extent each type of
water is characterized by a slightly different fauna.
During the season 1931-2 few observations were taken after the middle of January
upon which to base conclusions as to the changes in the disposition of the four types of
water as the season advanced. The surface temperatures at Sts. 824 and 825 (— 0:18
and 2:13°C.) seem to indicate that a retreat southwards of Weddell Sea water
carrying pack-ice took place between the middle of December (St. 766) and the middle
of January (Sts. 824 and 825). There were no deep observations at Sts. 824 and 825,
however, by which this can be confirmed. During the season 1932-3 a line of stations
was taken in early February across the eastern end of the Drake Passage (Sts. 1115—
1120), another in late February between the Falklands and South Georgia (Sts. 1121—
1131), and another in March from South Georgia across the Weddell Sea current to the
pack-ice edge in 69° 22’ S, 9° 37°5’ E (Sts. 1137-1153). Fig. 7 shows the position of the
isotherms, again calculated from the average temperature of a stratum 100 m. deep, at
the eastern end of the Drake Passage in early February and in the Weddell Sea in March
as found on these lines of stations. The figure shows a clearly perceptible southward
movement of the isotherms in the Drake Passage in February as compared with the
conditions in this area in November of the same summer (Sts. 1014-1020; Fig. 6). In
the Weddell Sea in March (Fig. 7) this southward movement of the isotherms is even
more pronounced, compared with conditions at the end of November and the beginning
of December (Fig. 6). It is doubtless connected with the break up and retreat south-
ward of the pack-ice as the season advances. Mackintosh (1934, p. 130, fig. 46) figured
the position of the pack-ice in the South Georgia—South Sandwich area in successive
months during the season 1930-1, and illustrated its retreat southwards from a position
near South Georgia in October to the middle of the South Sandwich group in February.
Mackintosh’s figure shows that the movement of the ice from the vicinity of South
Georgia to the south-east was less pronounced in the season 1930-1 than in the season
1931-2 with which we are concerned in this report. In early December 1931 the pack-ice
was near St. 767 (Fig. 1a), which was worked among drift ice and bergs in about the
latitude of the northern end of the South Sandwich group. By the end of January it
had retreated southwards to the position of St. 823 (Fig. 14) in the latitude of Elephant
and Clarence Islands. This was very far south of its position in the previous January,
as shown by Mackintosh, when the line of the ice-edge ran approximately from the
South Orkneys to the northern end of the South Sandwich group. In the season 1932-3
pack-ice was met with at the southern end of the South Sandwich group at the end of
RHINCALANUS GIGAS 293
November (St. 1045), but in March open water was found throughout the whole length
of the line in that month from St. 1138 to St. 1153.
PREVIOUS WORK
The species Rhincalanus gigas was first described by Brady (1883) from the collections
of H.M.S. ‘Challenger’, and subsequently Giesbrecht (1902) described a species from
the collections of the Belgica Expedition which he called R. grandis and which he be-
lieved to be identical with the R. gigas of Brady. Wolfenden also found this species in
the Gauss collections (Wolfenden, 1g11) and in the Discovery collections (Wolfenden,
1908), and established that the species described by Brady and Giesbrecht were the
same. R. gigas was also taken by the Terra Nova (Farran, 1929), by the Scotia (Scott,
1912) and by the Aurora (Brady, 1918) Expeditions.
Schmaus and Lehnhofer (1927) gave an account of the young copepodite stages of the
species from the Valdivia collections, and it is from the description of these authors that
the copepodite stages have been identified during the present work.
In the Antarctic summer of 1929-30 the floating factory ‘ Vikingen’ took a number of
plankton stations between the South Sandwich Islands and Bouvet Island and between
the South Orkney Islands and the South Sandwich Islands. The collections from these
stations, together with one station taken by the ‘ Norvegia’ in 1928, form the subject of
a paper by Ottestad (1932), in which the author dealt with the biology of certain of the
more important species of macroplanktonic Copepoda. In the short section devoted to
R. gigas the author arrived at certain conclusions which are to a large extent confirmed in
the present report.!
Hardy and Gunther (1935) have given some account of the distribution, both hori-
zontal and bathymetrical, of the species in the immediate vicinity of South Georgia, and
Mackintosh (1934) included the species in his general account of the horizontal distribu-
tion of the macroplankton in the Falkland Sector.
It is not intended in this report to give a description of the species, for which reference
should be made to the accounts of Brady (1883), Giesbrecht (1902) and Wolfenden
(1908, 1911). On the grounds of priority the name R. gigas will be used, as opposed to
Giesbrecht’s R. grandis.
Dist RIBUTION OF RHINCALANUS GIGAS
The material collected by the ‘Discovery II’ during her 1931—3 commission is far
more comprehensive than that of any previous expedition, although only a portion of it
has been examined and forms the subject of this paper. It will scarcely serve any pur-
pose, therefore, to give former records of the occurrence of R. gigas, but it may be noted
1 While the present report was in the press a further important paper by Ottestad has appeared
(Ottestad, P., 1936. On Antarctic Copepods from the “‘ Norvegia”’ Expedition 1930-1. Scientific Results
of the Norwegian Antarctic Expeditions 1927-8 et sqq. Norske Vid. Akad., Oslo, No. 15, pp. 1-44, text-
figs. 1-11). The paper deals with the biology of four of the commonest Antarctic species, Calanus
acutus, C. propinquus, Rhincalanus gigas and Metridia gerlachet.
D XIII 3
204 DISCOVERY REPORTS
that Farran (1929) found it in the Terra Nova collections as far south as 77° 30’ S near
Cape Royds and Cape Evans, and Wolfenden (1911) found isolated specimens in the
Gauss collection as far north as 46° S and one from 3000 m. between Tristan da Cunha
and Cape Town. The ‘ Valdivia’ also found very small numbers in the latitude of Cape
Town in the Atlantic and South Indian Oceans (Schmaus and Lehnhofer, 1927). ‘The
material obtained by the ‘ Discovery II’ gives a considerably better picture of the dis-
tribution of R. gigas in the Falkland Sector of the Antarctic than elsewhere, since ob-
servations in that sector were made in the summer months. The stations around the
Antarctic Continent, however, were taken during the winter so that the picture they give
is that of the winter distribution of the species.
HORIZONTAL DISTRIBUTION, SEASON 1931-2
Falkland Sector, November to mid-fanuary (‘Table III a)
The figures for the lines of equal numerical distribution (Fig. 8) and of equal per-
centage distribution (Fig. 9) in the Falkland Sector during the first half of the season
1931-2 allow certain broad generalizations to be made. The figures should be studied in
conjunction with the isotherm map (Fig. 5), in which, as already explained, the average
temperature for the surface 100 m. has been plotted for every station.
The area of maximum abundance of R. gigas is seen (Fig. 8) to be an area where the
combined hauls (250-100 and 100-o m. together) amounted by estimation to over
10,000 individuals. In this area R. gigas amounted to 75-100 per cent of the total
copepod catch (Fig. g). This region of maximum abundance is seen to include the waters
of the Drake Passage south of the Antarctic convergence, the western Scotia Sea, and
the waters of the South Atlantic Ocean south of the Antarctic convergence lying west,
north and north-east of the island of South Georgia. In the Drake Passage the area
of maximum abundance extends south of the o and — 1:o° isotherms, but in the western
Scotia Sea and South Atlantic Ocean it lies always north of the o° isotherm. The
Antarctic convergence forms the northern boundary of this area except at St. 746,
which is situated practically upon the convergence itself, and at St. 776, which is also
extremely near the convergence. At the latter station 86-5 per cent of the total copepod
catch was made up of Rhincalanus, although the actual number of individuals in the
combined hauls amounted to less than 10,000 (5325—see Table III a).
It is thus seen that the area of dominance and abundance lay in the warmer Antarctic
water in the South Atlantic and western Scotia Sea, where the temperature (average for
the surface hundred metres) was higher than o° and lower than 3-0° C. This water
constitutes that part of the West Wind Drift current in the Falkland Sector which
originates in the Bellingshausen Sea and is known as the Bellingshausen Sea current.
In the Drake Passage the area of maximum abundance extended into water from the
Bellingshausen Sea having an average temperature less than — 1:0° C. (St. 739) and less
than — 1°5° C. (Sts. 735 and 737). There are no observations in this particular season to
show the distribution of the species in the Bellingshausen Sea itself.
Within the area of abundance certain regions may be distinguished where the popula-
40° 30°
| |
SOUTH ATLANTIC OCEAN
67. ae
S.GEORGIA —
WEDDELL
SEA
| [CS
Fig. 8. Horizontal distribution of Rhincalanus gigas in the Falkland Sector of the Antarctic, mid-November
1931 to mid-January 1932. (1-m. nets, 250-100 m. approx. and 100-0 m. approx., both hauls combined.)
Numbers represent hundreds of individuals.
SAOX: BOUNDARY _OF
c= at
Fig. 9. Percentage distribution of Rhincalanus gigas in the Falkland Sector of the Antarctic, mid-November
1931 to mid-January 1932. (1-m. nets, 250-100 m. approx. and 100-0 m. approx.) Numbers represent
percentage of R. gigas in the total copepod catch in the upper and lower hauls together.
296 : DISCOVERY REPORTS
tion was particularly dense. The most evident embraced the two stations 737 and 739,
in the coldest water of the Drake Passage along the pack-ice edge (Figs. 1a, 8). At
St. 737 the estimated number in the combined hauls was 15,590, while at St. 739 it was
44,650. These two stations were situated just off the Antarctic continental shelf where
warm deep water wells upwards towards the surface (Deacon, 1933, pp. 180-1). Although
this is not evident from the position of the discontinuity layer at these two stations them-
selves (Table II a), they are nevertheless sufficiently near the region of upwelling for its
effects to be perceptible in the plankton. Other especially large catches were taken in the
area of abundance immediately south of the convergence in the South Atlantic west and
north of South Georgia, and at St. 803 (Figs. 1a, 8) where the estimated number in
the combined hauls was 19,948.
North of the Antarctic convergence in the South Atlantic, in sub-Antarctic water,
is an area where Rhincalanus formed 50~75 per cent of the total copepod catch. Here the
catches in the combined hauls amounted by estimate to between 5000 and 10,000
individuals. This area was missing in the Drake Passage where the Antarctic convergence
formed a much more pronounced limit to the region of density of the species. Here the
convergence sharply divided the area of maximum abundance from sub-Antarctic water
in which Rhincalanus formed 25-50 per cent of the total copepod catch and where
between 2500 and 5000 individuals were taken in the combined hauls. In the South
Atlantic east of South Georgia there are no observations defining the northern boundary
of the 5000-10,000 zone at this time of year, but the 5° C. isotherm may be suggested as
its northern boundary.
This marked abundance of Rhincalanus in Antarctic water of Bellingshausen Sea
origin in the Falkland Sector is in striking contrast with the comparative paucity of the
species in the cyclonic current originating in the Weddell Sea (Fig. 8). Within this mass
of water moving north-eastwards out of the Weddell Sea, having an average tempera-
ture less than 0° C., Rhincalanus amounted to less than 15 per cent of the total catch
(Fig. 9) and the numbers of individuals taken at each station were less than 500 in the
two hauls combined.
There is thus a pronounced difference, so far as the abundance of R. gigas is con-
cerned, between the two main water masses in the Antarctic surface water of the Falk-
land Sector. The Bellingshausen Sea current, flowing through the Drake Passage around
the western end of South Georgia into the South Atlantic, is characterized by a great
abundance of this species, while the Weddell Sea cyclonic current, flowing along the
east coast of Graham Land and east of South Georgia towards the South Sandwich
Islands, is characterized by a relative scarcity of R. gigas but by a rich copepod fauna of
which R. gigas is not an important constituent.
Between these two masses of water is an area of variable extent where their influences
mingle. North of South Georgia, as already mentioned, a tongue of Weddell Sea water
pushes westwards and causes the 5000 and 2500 lines of equal numerical distribution of
R. gigas to take a bend westwards before turning eastwards again across the South
Atlantic. South of South Georgia, where another tongue of Weddell Sea water pushes
RHINCALANUS GIGAS 297
northwards between the South Orkneys and South Georgia, the lines of equal numerical
distribution are widely spread out (Fig. 8).
In the South Atlantic, where Weddell Sea water comes into contact with water of
Drake Passage and Bellingshausen Sea origin roughly along the 1-o0° C. line, the dis-
tribution lines are crowded together. ‘They approximate to the position of the o and
1-0 isotherms, and where, in about longitude 23° W, the o° isotherm takes a south-
ward bend, the 500 and rooo and the 25 and 50 per cent equi-distributional lines take
a southward bend also. In this position the surface water appears to have a southward
movement (Deacon, 1936, in press), and the course of the lines of equal distribution of
R. gigas shows that this southward movement of warmer water has its effect upon the
copepod fauna.
There is thus a sharp boundary between the copepod fauna of the South Atlantic
water of Bellingshausen Sea origin and that of Weddell Sea origin. In the fauna of the
former kind of water Rhincalanus predominates, while in the fauna of the latter type of
water other species predominate, and the boundary between the two faunas lies along
the o and 1-o° isotherm lines, which, east of South Georgia, are close to each other.
Immediately north of the island, however, and in the Scotia Sea, a spreading out of the
lines of equal distribution indicates a much greater degree of mingling of the influences
of the two types of water. North of the island Weddell Sea influences appear to pre-
dominate in the fauna (Figs. 8, 9), while south of the island in the Scotia Sea the in-
fluence of water from the Bellingshausen Sea appears to predominate.
In general it may be said that in the Scotia Sea and in the South Atlantic east and north
of South Georgia (Nov. 1931—Jan. 1932) the southern limit of distribution of R. gigas
corresponded in position with the o° isotherm (average of o—100 m.). South of this line
the catches amounted to less than 500 individuals and usually constituted less than 15 per
cent of the copepod plankton. The o° isotherm is also the boundary of Weddell Sea
water carrying melting pack-ice or in which pack-ice has recently melted. In the
southern Drake Passage, however, there is an abundance of Rhincalanus in water con-
siderably colder than this, carrying melting pack-ice, which has been ascribed to the
upwelling of warm deep water along the Antarctic continental shelf.
Falkland Sector, mid-January to mid-February (‘Table II 6)
Not many observations were made at the end of the season 1931—2 by which changes
in the distribution of the population can be judged. At the end of January a line of
stations was run from the farthest point south in the Weddell Sea, at the pack-ice edge
in 69° 59'S and 23° 53’ W to South Georgia (Fig. 1). This line traversed water
flowing out of the Weddell Sea on the west along the coast of Graham Land. At the four
most westerly stations (822—5—-see ‘Table III a and Fig. 10) the catches of Rhincalanus
amounted to between 400 and 700 individuals. Sts. 824 and 825 show a diminution in
numbers compared with St. 768 in the middle of December but no marked change com-
pared with St. 766 (Figs. 1a, 8). No observations were made farther south in this water
during the early part of the season with which to compare Sts. 822 and 823. In the
298 : DISCOVERY REPORTS
middle of February a line of four stations was taken between the Falkland Islands and
South Georgia (Fig. 1 6). In this area a diminution in numbers is found compared with
the conditions at the beginning of December (cf. Figs. 8, 10). This decrease, however,
is very much more striking on the Falkland or sub-Antarctic side of the convergence
than on the South Georgia or Antarctic side. On the sub-Antarctic side Sts. 828 and
40° 30° 20°
aig ae SS
SOUTH ATLANTIC OCEAN
ie)
\
ANTARCTIC
Cc
Sass ee eae
| i :
ten, S. GEORGIA
4S
7 H
SOUTH
SANDWICH *
Is.
SS ORKNEY
Is.
WEDDELL
GRAHAM
LAND
BELLINGSHAUSEN
/ SEA Cy
Fig. 10. Horizontal distribution of Rhincalanus gigas in the Falkland Sector of the Antarctic, mid-January
to February 1932. (1-m. nets, 250-100 m. approx. and 100-0 m. approx., both hauls combined.) Numbers
represent hundreds of individuals.
829 in February may be best compared with Sts. 750 and 751 at the end of November
and the beginning of December:
T
St Date Number of R. gigas St Date Number of R. gigas
: 1931 in combined hauls i 1932 in combined hauls
750 30. xi 5475 828 17. li 277
751 I. Xil 9715 829 18. il 253
On the Antarctic side of the convergence the catches at Sts. 830 and 831 still amounted
in February to more than 8000 individuals in the two hauls combined. It is evident that
at the end of the season 1931-2 the Antarctic convergence formed a barrier to the dis-
tribution of Rhincalanus and limited its extension into the sub-Antarctic Zone much
more strictly than in November and December, when the species was found in abund-
RHINCALANUS GIGAS 299
ance in sub-Antarctic water. During December, January or February, therefore, some
change apparently occurred in the copepod fauna involving the disappearance of Rhin-
calanus from the surface 250 m. in sub-Antarctic water. Further evidence of this change,
limiting the northward range of Rhincalanus, is to be found on the line from South
Georgia to South Africa at the end of the season (Fig. 11):
St | Date Number in
| ¢ | 1932 | combined hauls
|
South of Antarctic convergence | 834 | 23. il 594 |
North of Antarctic convergence | 835 25.11 o* |
| 836 27. il 45
| 837 | 27.11 fo)
* Upper net only.
The above figures show, additionally, that on both sides of the convergence a far
more pronounced diminution of R. gigas had taken place by the end of February north-
east of South Georgia than had taken place by the middle of the month west of the island.
Around the Antarctic Continent, April to October (Table III c)
During the winter months, around the Antarctic Continent, we find that the con-
vergence continues to limit the distribution of R. gigas northwards, and that the species
is not found in sub-Antarctic water except in very small numbers (Table III c and
Fig. 11). The condition found in February between the Falkland Islands and South
Georgia and north-east of South Georgia thus appears to represent the winter condition
of the distribution of the species.
The numbers of individuals taken on the circum-Antarctic lines of stations were very
much smaller than during the summer in the Falkland Sector. Only at one station (852)
on the Cape Town—Enderby Land line and at two stations on the Enderby Land-
Fremantle line (857 and 862), did the combined hauls amount to more than 1000
individuals (Fig. 11).
On the line taken at the end of May from Fremantle to the ice-edge, and from the
ice-edge to Melbourne (Fig. 11), the catches were very small indeed, except at the most
southerly station (887) at the pack-ice edge south of Australia, where comparatively
large numbers (587) of young forms and nauplii were taken. A catch of more than 100
individuals was taken at St. 883, immediately south of the convergence between Fre-
mantle and the ice-edge, and of more than 250 individuals immediately south of the
convergence on the line from the ice-edge to Melbourne. Elsewhere on these two lines
the catches amounted to less than roo individuals.
At the end of June, when returning from Melbourne to the ice-edge south of the
Tasman Sea, the catches at the four stations (go3—6) were extremely small, but again
a catch of more than 100 individuals was taken at the station (904) immediately south
of the convergence (Fig. 11). On the line from the ice-edge up to New Zealand Rhin-
calanus had almost disappeared from the catches, but here also the greatest number
(more than 25 individuals) was taken at the station (g1g) just south of the convergence.
300 DISCOVERY REPORTS
=SS= APPROXIMATE POSITION OF BOUNDARY
BETWEEN EAST & WEST WIND DRIFTS
West 180 East
Fig. 11. Horizontal distribution of Rhincalanus gigas around the Antarctic Continent, winter months,
February to October 1932. (1-m. nets 250-100 m. approx., 100-0 m. approx., both hauls combined.)
Numbers represent hundreds of individuals.
RHINCALANUS GIGAS 301
Owing to the refitting of the ship in Auckland and to other work around New Zealand
there are no observations for the two months July and August 1932. During September,
however, at the beginning of which month the ship left New Zealand for the last stages
of her circumpolar cruise across the Pacific Ocean, it was found that Rhincalanus
had virtually disappeared from the catches. Only at St. 961, just south of the converg-
ence in the western Pacific, a catch of 26 individuals was obtained (Fig. 11). Rhincalanus
reappeared in the catches at St. 978 off Cape Horn in early October.
Two processes, then, appear to take place during the winter months around the
Antarctic Continent—firstly, the restriction of Rhincalanus to the Antarctic zone so that
the species becomes wholly Antarctic instead of mainly Antarctic, and secondly the
diminution of the catches followed by the disappearance of Rhincalanus from the surface
250 m. after about mid-winter. It reappears in this layer again in the following spring.
BATHYMETRICAL DISTRIBUTION, SEASONS 1931-2 AND 1932-3
Falkland Sector (Table IV a)
It is proposed now to deal with the bathymetrical distribution of R. gigas, so far as it
can be understood from these hauls, before considering the horizontal distribution in
the Falkland Sector during the second of the two seasons covered by this work, since the
horizontal distribution in the early part of the season 1932-3 can only be understood in
the light of the facts revealed by a study of the vertical movements of the species from
month to month.
Although the two oblique towings made with the 1-m. net from 250 to 100 m. and
from 100 too m. do not give a very adequate picture of the vertical distribution and
movements of the plankton, yet some idea of the vertical movements from month to
month can be obtained from them.
Fig. 12 shows the percentage of the total catch in the upper (100-0 m. approx.) and
lower (250-100 m. approx.) hauls at stations in the Falkland Sector during November
and December 1931 and January and February 1932, between South Africa and Aus-
tralia in April 1932, and again in the Falkland Sector in October, November and
December 1932 and February 1933. All the catches illustrated in the diagram amount
to over 500 individuals in the combined hauls, with the exception of those shown in
lighter shading which represent hauls of more than 250 but less than 500 individuals.
The diagram does not include any stations in Weddell Sea water, since special conditions
appear to exist in that area so far as this species is concerned.
A difference in the proportion of the catch taken in the upper and lower nets in sum-
mer and winter is immediately noticeable from the figure. This difference is most
pronounced between the winter months, April and October 1932, and the summer
months of the season 1932-3 (lower half of the figure), but is less clearly shown by
the diagram for the summer months of the previous season 1931-2 (upper half of the
figure).
During April 1932, in the South Indian Ocean, and October 1932, in the Drake
D XIII 4
302 DISCOVERY REPORTS
Passage, the greater proportion by far of the total catch at nearly all stations occurred in
the lower nets. In the middle of the month of April 1932 there were three stations
(850, 851 and 853) at which an almost equal proportion of the catch occurred in the upper
and lower nets and another similar station (863) at the end of the month just south of
NOVEMBER 1931 DECEMBER 193]
NorTH Sout] Ice Eoce NORTH SoUTH|NoRTH SouTH|NoRTH SOUTH
JAN 1932 |FEBRUARY 1932
|West
—
East
oo
RR
0
NK
Cc
AC. ANTARCTIC
CONVERGENCE
@™™ MORE THAN 500
LESS THAN 500
wi S)
ul
je
>
UPPER NET
|00mM-O™. APPROX:
ine)
on
C—
5 !
E ! ,
ee ! !
as ! !
[e) if 1
Fe oO I 1
i I if
3 S ' I
=I uw | | 5
fas}
APRIL 1932 OCTOBER 1932 NOVEMBER 1932 DECEMBER 1932 | FEBRUARY 1933
N S|NortH Soutn | NorTH South | NoRTH SouTH|NORTH SoutH N S| = | aaa
o—-m | mu—-GQouaonw tunwoo at ae warn gy ele ete ae el eae
%| 888 | S8SSsees AoaaH Ha | SO] So 90] SG SS8s5 | 68 | Sods
ist) AIC AIC AIC AC
: go | | | |
hs | | 1 I
ete ee ' I I I 4
PA ud 4
| ! | ' 4
a co 4
Wu s = | I I I Y
se (So) ut | I | I 4
a1 i= ! \ I g
a = oO 4
(e} lo I \ ! \ 4
ie) Tp) | | ] | 4
S 4)
Se Oo 4 AY
S = na a
ka MZ BY
ty 8 > iL j
Fb SS <x igg y
2 > 3 Z
“oO ‘ay 4
u Oo mm AZ Yj
a W j
ST fm AZ 4
4 4
wd 4 4
Fig. 12. Percentage of total catch of Rhincalanus gigas in upper and lower 1-m. nets, 1931-32-33. Falkland
Sector (excluding stations in Weddell Sea water) and Indian Ocean Sector.
the convergence. At the six other stations taken during April almost the whole catch
occurred in the lower nets. In November 1932, however, the greater proportion of the
total catch was taken in the upper nets. The same condition was found throughout
December and also in February 1933, although two stations in that month taken in
the Drake Passage showed a majority in the lower nets, and at St. 1123, on the sub-
Antarctic side of the convergence in February between the Falklands and South Georgia,
the entire catch was in the lower nets. During the winter months the catches were
mostly too small to give reliable percentages: during May and June, however, the catches
were entirely or mainly in the lower nets (‘Table III c). There are no observations for
RHINCALANUS GIGAS 303
July or August 1932, but in September in the South Pacific Ocean Rhincalanus had
practically disappeared from the catches.
It seems, then, that R. gigas spent the summer months November 1932 to at least
February 1933 at the surface, mainly in the 100-0 m. layer. The progressive reduction
of the catches during the winter months April-September 1932 in the West Wind Drift
current around the Antarctic Continent, together with the descent of the catches from
the upper to the lower nets in April, suggests that the species left the surface and
descended into depths below 250 m. during the winter. During September 1932 it was
out of range of the 250-100 m. net but came within its range in October 1932.
The same process appears to have taken place in the previous season, 1931~2, but the
movements seem to be less clearly defined. In November of that season the larger pro-
portion of the catches at most of the stations was in the lower nets. It is noticeable,
however, that stations immediately south of the Antarctic convergence in the Drake
Passage (Sts. 731, 733, 745) show a majority in the upper nets. During December in
the western Scotia Sea and in South Atlantic water north and west of South Georgia the
stations immediately south of the convergence (Sts. 755, 775 and 751, which was taken
almost on the convergence) again show a majority in the upper nets, while those farther
removed from the convergence (Sts. 753, 757,759, and 774) show a majority in the
lower nets. At three stations also during these months—Sts. 726, 737 and 769, which
were taken in places where warm deep water wells upwards to the surface—a majority
was also found in the upper nets. St. 726 is situated near the coast of South America,
St. 737 near the continental shelf, and St. 769 on the ridge between the South Shet-
lands and the South Orkneys. At the few stations taken in the second half of
December 1932 and in January and February 1933 the majority of the catch was in
the upper nets.
Thus it appears that the rise of Rhincalanus to the surface in the season 1931-2 in
Antarctic water away from the convergence took place in early December, nearly a
month later in the year than in the following season 1932-3, when the rise to the surface
occurred at the beginning of November. Deacon (1936) has found that the hydrological
data show the season 1931-2 to have been colder and “later” (with respect to the south-
ward movement of the isotherms) than the season 1932-3. The average temperature of
the surface 50 m. of water in the region round South Georgia between 52 and 56° S and
33-40° W was 1°50°C. in the middle of January 1932 and 1-88" C. in the middle of
January 1933. In 1931-2, however, the rise of Rhincalanus to the surface appears to have
already taken place in November at stations near the convergence, so that it is possible
that the spring ascent to the surface may take place earlier near the convergence than
elsewhere. The precise conditions under which this ascent takes place are at present
unknown, but it is perhaps to be expected that it will occur earlier near the convergence
than elsewhere, since the warming effect of the approach of summer has been found
(Deacon, 1936) to become marked sooner in the region just south of the convergence.
It is permissible then to suggest that the spring ascent is connected with the attainment
of a certain temperature by the water at the surface, and, indeed, that the whole
4-2
304 ; DISCOVERY REPORTS
phenomenon of seasonal vertical migration is connected with temperature. Somme
(1934) suggests that light intensity is also an important factor.
From the somewhat scanty data set forth above it seems possible to conclude that
Rhincalanus, in the Bellingshausen Sea current and the Antarctic water of the West
Wind Drift generally, undertakes a seasonal vertical migration similar to that established
by Sémme (1934) for Calanus finmarchicus and Calanus hyperboreus in the northern
hemisphere, spending the summer months November or December to about February
at the surface and descending in April into the 250-100 m. layer and sinking still farther,
below 250 m., at the beginning of May. It reappears in the 250-100 m. layer once more
in October. Thus it follows that the winter months are passed in the warm deep water,
in water of higher temperature and salinity, which is moving southwards and will there-
fore tend to carry the animal southwards. In the summer the species inhabits the north-
ward-flowing Antarctic surface water, which will tend to carry it once more in a north-
ward direction.
This theory of the seasonal vertical movements of Rhincalanus gigas receives con-
firmation from the work of the ‘ Discovery II’ on her third commission (1933-5). Dr
N. A. Mackintosh, under whose direction the work was carried out, has given a pre-
liminary account of some of its more immediate results in Nature (1935). Part of the
ship’s programme during the seasons 1933-4 and 1934~5 involved the repetition at dif-
ferent times of the season of a line of plankton stations along the meridian of 80° W
(western end of the Drake Passage). ‘This line of stations was taken in December 1933
and March, September, October and November 1934. At each station a series of six
vertical hauls was made, using the 7o-cm. closing net, from various depths between
1000 m. and the surface. A preliminary examination of the samples obtained from these
hauls reveals vertical movements on a large scale, not only of R. gigas but of several other
macroplanktonic species. Mackintosh outlines the seasonal changes in the bathymetrical
distribution of Rhincalanus as an illustration of these movements. In December the
species was mainly concentrated at the surface above the 250-m. level, as was suggested
by the hauls with 1-m. nets taken in 1931-2 and 1932-3. In March it tended to sink,
larger catches being taken around the 500-m. level, especially north of the convergence.
In September it was practically confined to the warm deep water below 500 m., but in
October and November it regained the Antarctic surface water above 250 m.
Weddell Sea (‘Table IV 5)
There are no observations extending over a long period by which to judge the seasonal
vertical movements of Rhincalanus in the Weddell Sea, but stations were taken in this
water in December and January 1931-2 and November, December, February and
March in the season 1932-3. Fig. 13 shows the percentage of the total catch taken in
the upper and lower nets at all the stations in Weddell Sea water during the two seasons
and is constructed on the same plan as Fig. 12.
In December and January, in the season 1931-2, the majority of the catch was in the
lower nets at all stations taken east of South Georgia in the oldest type of Weddell Sea
RHINCALANUS GIGAS 305
water—that is water flowing out of the Weddell Sea with an average temperature for
the surface 100 m. between 0 and 1:o° C. (Sts. 779, 797, 798, 799, 806 and 808). At four
other stations in colder water, at which the average temperature was between — 1-0 and
o° C. (water in which ice has recently melted), that is at Sts. 795, 804, 807 and at 761, near
the South Orkneys, the catch was likewise almost entirely in the lower nets. At all other
stations in water flowing out of the Weddell Sea the catch occurred mainly or entirely in
the upper nets.
DECEMBER 193! JANUARY 1932
ORKNEYS-S.GEoRGIA|WEST — East|NorTH - South {ice EDGE
UPPER NET
100m—-Om. APPROX:
LOWER NET
250m- |00m.APPROX'
S.ORKNEYS —
S erae
UPPER NET
\00m- Om. APPROX:
MMM MORE THAN 500
LESS THAN 500
LOWER NET
250m - 100m. APPRO
Fig. 13. Percentage of total catch of Rhincalanus gigas in upper and lower 1-m. nets, 1931-2 and 1932-3.
Weddell Sea.
At the stations in the ‘“‘oldest’’ type of Weddell Sea water (o-1-0° C.) east of South
Georgia (Sts. 779, 797, 798, 799, 806), at which the catch was in the lower nets, it
seems reasonable to assume that the Rhincalanus population originated from the South
Atlantic and had been carried into water from the Weddell Sea by southward-moving
warm deep water. At Sts. 795, 804, and perhaps 807, in Weddell Sea water carrying
melting pack-ice, the origin of at least a part of the population is no doubt the same, and
306 ; DISCOVERY REPORTS
at St. 761, near the South Orkneys, at least a part of the population will have been carried
southward in warm deep water from the Scotia Sea. Since the population at these
stations occurred almost entirely in the lower nets we may assume that it originated
outside the Weddell Sea in the Scotia Sea or South Atlantic. At nearly all the other
stations in water flowing out of the Weddell Sea the population must belong to the
stock of Rhincalanus in the Weddell Sea itself (Sts. 765, 766, 768, 780, 809, 812, 822-5).
At Sts. 765, 766 and 768, however, it may be expected that a large proportion of the
population sampled by the upper nets originated in the Drake Passage, since in this area
there is a large degree of mixing of the waters of the Bellingshausen Sea and Weddell Sea
currents. At all these stations the catch appeared in the upper nets. Sts. 815, 816 and
817 were taken in the current that flows westwards into the Weddell Sea along the coast
of Coats Land south of 66° S. At these stations the catch was in the lower nets. At
St. 813, at which there was a small majority in the lower nets, part at least of the
population belongs to the westward-flowing current, since this station lay on the
boundary between water flowing westwards into the Weddell Sea and that flowing east-
wards out of it. The deeper layers of this water, as already explained (p. 282), originate
in warm deep water in the South Indian Ocean, so that it seems that Rhincalanus enters
the Weddell Sea either from the South Atlantic in warm deep water or from the Indian
Ocean in the warm deep current that flows westwards into the Weddell Sea south of
66° S. Deacon (1936) found Atlantic water as far south as Sts. 806 and 808, but at
St. 807 and the other stations farther south the deep water was found to originate mainly
from the current flowing westward into the Weddell Sea south of 66°S. In water
flowing out of the Weddell Sea, however, Rhincalanus apparently rises to the surface,
since at nearly all the stations in the Weddell Sea north-easterly current, except those in
the very ‘‘ oldest” water, the catches were in the upper nets. A hydrological explanation
of this is available in the case of certain stations in the centre of the Weddell Sea
cyclonic system (Sts. 809, 812, 813, 822 and 823). These stations lay in an area inter-
mediate between the westward current flowing into the Weddell Sea and the water
flowing north-eastwards out of it. In this area, as Deacon shows in work now in the
press (1936), there is an upwelling of warm deep water towards the surface in the deeper
layers. Although the isotherms within the surface 250 m. give no clear indication of
upwelling it may exist to a small extent in the upper layers and may still influence the
plankton above the 250-m. level. At the stations in water flowing out of the Weddell Sea
to the west near South Georgia (Sts. 765, 766, 768, 780 and 825) a large part of the
population very probably belongs to the Bellingshausen Sea water, which here mingles
with water from the Weddell Sea.
It seems necessary to bear in mind, when considering these questions of the vertical
distribution of the plankton, that variations in the level of concentration are not brought
about so much through the conveyance of plankton from one level to another by the
movements of masses of water as through the active migration of the plankton along
temperature gradients to levels where an optimum temperature occurs. For instance,
the upwelling of warm water in the centre of the Weddell Sea, above mentioned, in-
RHINCALANUS GIGAS 307
volves no marked upward movement of a mass of water such as could carry the plankton
to the surface, but it does effect a raising of the level at which the temperature, or some
other factor, is an optimum and might thus bring about the active concentration of the
plankton at that level.
In the season 1932-3, during November and December, at all the stations in Weddell
Sea water, except St. 1052 which was taken in Weddell Sea water of the “‘oldest”’ type,
the majority of the catch was in the upper nets. At St. 1052 there was an approximately
equal proportion in the upper and lower hauls. ‘Thus, as in the previous season, the
population of Rhincalanus in the “younger” water flowing out of the Weddell Sea
(water colder than 0° C.) belongs to the Weddell Sea stock and was found at the surface,
while the population at the only station taken in the “‘ oldest”’ type of Weddell Sea water
(water between o and 1-0° C.) was found largely in the lower haul and part of it at any
rate must have come from farther north in warm deep water. On the line into the Weddell
Sea taken during March 1933, Sts. 1138, 1142 and 1144 were taken in water flowing north-
eastwards out of the Weddell Sea (Fig. 26), while Sts. 1148 and 1150 were taken in water
flowing westwards into the Weddell Sea. At St. 1142 the entire catch of over a thousand
individuals occurred in the lower net. ‘This station, as the 100-m. temperature indicates,
was taken in a tongue of warmer water possibly moving southwards from the South
Atlantic. The Rhincalanus population here is probably, therefore, of definitely South
Atlantic origin, carried southwards in warm deep water. At St. 1138, at which most of
the catch was in the lower nets, part at least of the population belongs to the warm deep
water and part to the Weddell Sea itself, since this station was taken near the boundary
between the Bellingshausen and the Weddell Sea currents.
At Sts. 1148 and 1150, in water flowing westwards into the Weddell Sea, the majority
of the catch was in the upper hauls, although the proportion in the lower nets was high.
At the stations taken in this water in January of the previous season (Sts. 816 and 817)
the majority of the catch was in the lower nets and it was assumed that the population
which enters the Weddell Sea in this current originates from the warm deep water of the
South Indian Ocean. If we compare these two stations with Sts. 1148 and 1150 it is
noticeable that the discontinuity which marks the upper limit of the westward-flowing
deep water lies between 70 and 80 m. at St. 1150 (‘Table I14), while St. 1148 lies on the
boundary between the westward- and eastward-flowing water, where, as already explained,
warm water wells upwards in the lower layers. At Sts. 816 and 817, on the other hand,
the discontinuity is found at a depth of about 150 m. (Table Ila). This might well
account for the fact that a comparatively high proportion of the catch of Rhincalanus
was taken in the upper nets at Sts. 1148 and 1150, but in the lower at Sts. 816 and
817.
On the evidence available it is not possible to generalize much about the vertical dis-
tribution of Rhincalanus in the Weddell Sea. It will be shown later that the population in
this area is probably not endemic (pp. 330-2) and must originate from waters outside the
Weddell Sea area. From the foregoing account of the vertical distribution it may be said
that the population of the Weddell Sea is derived from two sources—from the current
308 ; DISCOVERY REPORTS
flowing westwards into the bight south of 66°S and known as the East Wind Drift current
and from the South Atlantic warm deep water. The main body of the population, as
sampled in the colder water carrying ice, is probably carried into the Weddell Sea in the
East Wind Drift, but where water from the Weddell Sea meets with warmer water from the
Bellingshausen Sea, north of the Scotia Arc and farther east as far south as St. 808, a sparse
population is found which owes its origin to Atlantic warm deep water. The population
in the East Wind Drift flowing into the Weddell Sea, in its turn, originates in warm deep
water in the South Indian Ocean. It appears to rise to the surface before leaving the
Weddell Sea in the north-easterly current and this, at least partly, may be due to the
upwelling of warm water which takes place in the centre of the circular Weddell Sea
current system and along the divergence region between the two water movements
which make up that system.
These conclusions are largely in agreement with those of Ottestad (1932), who has
already suggested that the stock of Rhincalanus in these waters belongs not properly to
the Weddell Sea but to waters outside that area and is carried into it by southward-
moving water from the South Atlantic.
HORIZONTAL DISTRIBUTION, SEASON 1932-3
Falkland Sector, October to December (‘Table III 6)
The lines of equal distribution of R. gigas for the first half of the season 1932-3
(Figs. 14, 15) show certain differences from those for the season 1931-2. The area of
maximum abundance is greatly reduced, and only at two stations (1017 and 1025),
between the Falklands and South Georgia, did the catch in the combined nets exceed
10,000 individuals. The line of stations at the western end of the Drake Passage was
taken during the last week in October, over a month earlier in the year than in the
previous season. As we have seen (pp. 301-3) the spring ascent to the surface from the
winter level of the species was not yet completed at that time. The comparatively small
numbers taken on this line may therefore be attributed to the fact that Rhincalanus had
not yet completed its ascent into the range of the 250-100 and 100-0 m. nets when the
line was taken.
In the spring of 1932-3 the Bransfield Strait was found to be clear of pack-ice, the
edge of which lay farther south in the Bellingshausen Sea than at the same time of year
in the previous season. The most southerly station—St. 735, on the Western Drake
Passage line in November 1931—lay in 63° 55’S and 73° 28-8’ W (Fig. 1a), while at
the end of October 1932 the most southerly station, at the edge of the pack-ice, was
taken in 66° 45-7’ S and 80° 19-8’ W (St. 994, Fig. 2a). In October 1932 and early
November the edge of the ice was followed into the Bransfield Strait to Deception Island
and finally as far as the longitude of Joinville Island (Fig. 2 a). R. gigas, and indeed the
Copepoda generally, were found to be practically absent from the Bransfield Strait and
from the coldest Bellingshausen Sea water (with a temperature lower than — 1-5° C.,
carrying unmelted pack-ice). The plankton as a whole in this area was extremely poor.
Fig. 14. Horizontal distribution of Rhincalanus gigas in the Falkland Sector of the Antarctic, October to
December 1932. (1-m. nets, 250-100 m. approx., 100-0 m. approx., both hauls combined.) Numbers
represent hundreds of individuals.
25%, INS,,
97566835
“05
75%.
>
oe
aa.4> ae
pe 14, ARES
90°
Fig. 15. Percentage distribution of Rhincalanus gigas in the Falkland Sector of the Antarctic, October to
December 1932. (1-m. nets, 250-100 m. approx., 100-0 m. approx.) Numbers represent percentage of
R. gigas in total copepod catch in the upper and lower hauls together.
D XUI 5
310 : DISCOVERY REPORTS
At two stations, however, situated somewhat to the north at the western entrance to the
Bransfield Strait (Sts. 1000 and 1001) an appreciable catch was taken. Here the catches
amounted to 425 and 931 individuals respectively. These twostations lay near the Antarctic
continental shelf, where, as already explained, there is upwelling of warm deep water
towards the surface, and it may be that at these two stations the Rhincalanus population
is carried upwards from its winter level by upwelling warm deep water as was found at
the stations in the Southern Drake Passage in the previous season.
The area of abundance of R. gigas (more than 5000 individuals) during the period
from late October to the end of December 1932 was again found in the Drake Passage
and the western Scotia Sea (Fig. 14). It occupied that part of the West Wind Drift and
Bellingshausen Sea currents in the Drake Passage and between South Georgia and the
Falkland Islands. South of the Falklands it embraced all stations at which the average
o-100-m. temperature was higher than — 1-0° C. and lower than 5-0° C. and included
stations in the sub-Antarctic zone between the Falklands and South Georgia, and in
sub-Antarctic water in the western Drake Passage. In the preceding season the 5000
line included stations in the sub-Antarctic zone between the Falklands and South
Georgia, but none in the western Drake Passage where the 3° isotherm formed the
northern boundary of both the 5000 and 10,000 regions of abundance. It thus does
not include Bellingshausen Sea water carrying melting or unmelted pack-ice. In the
eastern part of the area of abundance, south-west of South Georgia, the 0° isotherm
forms the approximate southern boundary of the region where the catches exceed 2500
individuals.
The stations in the Weddell Sea water east of South Georgia and in the Scotia Sea
were taken at the end of November and beginning of December, about a week earlier in
the year than the stations in the corresponding position in the previous season (Sts. 761—
8). The same comparative scarcity of Rhincalanus can be seen in the colder Weddell Sea
water carrying pack-ice (colder than o° C.) in the season 1932-3 as in the previous year.
At only one station (1047) in Weddell Sea water colder than o° C. was the catch in both
nets together in excess of 500 individuals. At nearly all of them it was less than 250
individuals. East of South Georgia there is a tongue of Weddell Sea water running
northwards and westwards (Fig. 6) similar to that observed in 1931-2. The lines of
equal distribution of Rhincalanus likewise take a similar bend to the west and north
before turning east across the South Atlantic. There is also a spreading out of the lines of
equal distribution in the Scotia Sea south of South Georgia, where the influence of the
Weddell Sea and Bellingshausen Sea currents mingle.
It is seen from the above that the stations which correspond in date and position in
the two seasons (those around South Georgia and in the Scotia Sea) do not show marked
differences in the distribution of R. gigas, so that it is perhaps justifiable to attribute those
differences in distribution which do appear in the Drake Passage to the earlier date of
the stations in these waters in 1932-3 than in 1931-2. They were taken before the spring
ascent to the surface had been completed in the former season but after its completion in
the latter.
RHINCALANUS GIGAS 311
Falkland Sector, February to March (‘Table III 6)
The line of stations from the South Shetlands to the Falklands taken in early
February (Sts. 1115, 1116, 1117 and 1119) shows a striking reduction in numbers in
this region compared with the conditions at the beginning of November (Fig. 16). At
Sts. 1116 and 1117 the catches in the two nets combined amounted to 2860 and 2416
individuals respectively, compared with catches in November of over 5000 and, at
St. 1017, of over 10,000 (Fig. 14). At St. 1119, north of the convergence, only 80 in-
dividuals were taken in the two nets together.
pePROX BOUNDA
Nae DRIFT
34
Fig. 16. Horizontal distribution of Rhincalanus gigas in the Falkland Sector of the Antarctic, February to
March 1933. (1-m. nets, 250-100 m. approx., 100-0 m. approx.) Numbers represent hundreds of in-
dividuals.
On the line between the Falkland Islands and South Georgia at the end of February
(Fig. 16) we find conditions closely resembling those found in this area in the February
of the preceding season (Fig. 10). At the three stations in Antarctic water the catches
were very large and amounted to more than 10,000 individuals at the more westerly
(St. 1125) and more than 5000 at the more easterly, near South Georgia (St. 1127). At
St. 1131, at the eastern end of the island, the catch amounted to more than 2500 in-
dividuals. At Sts. 1122 and 1123, however, in sub-Antarctic water, the catches of
Rhincalanus were small and did not exceed 500 individuals—37o and 328 respectively.
These two stations and St. 1119, south of the Falklands, therefore, again show the
5-2
312 DISCOVERY REPORTS
restriction of Rhincalanus to Antarctic water at the end of the season which we have
already noticed (pp. 298-9). It may be regarded as the winter condition and as a
regularly occurring process.
The line between the South Shetlands and the Falklands also shows a feature to which
Mackintosh (1934, p. 121) has already drawn attention. This is the sharp division be-
tween the moderately rich catches at the two northerly Antarctic Stations (1116 and 1117)
and the comparatively very poor catch at the most southerly station (1115). Mackintosh
has already shown that this line of demarcation can be drawn in the southern Drake
Passage for the plankton as a whole, and from comparisons of its positions at different
dates in different years he suggested that the line moves southward during the season.
At the beginning of the season 1932-3, at the end of October and beginning of November,
there was a similar line of demarcation so far as the distribution of R. gigas is concerned
between Sts. 992 and 994 and between Sts. 1014 and ro15 (Fig. 14), but these stations
are too far apart for the exact position of the line to be fixed. Its position in February
between Sts. 1115 and 1116 does not, however, suggest that it has moved appreciably
between the beginning and the end of the season. Mackintosh (1934, p. 121) further
suggested that there is a rich plankton in the central part of the Drake Passage which
spreads farther southwards towards the end of the summer. We have seen, however,
that so far as R. gigas is concerned, there is a diminution in quantity towards the end of
the summer in the Drake Passage, and the largest catches on the February line, taken
at Sts. 1116 and 1117, do not suggest any marked southward movement of the area of
abundance. In fact the indications are that the area of abundance moves away north-
eastwards towards South Georgia—as indeed one might expect in view of the general
direction of flow of the surface waters. Thus, while reduction in numbers takes place in
the Drake Passage, the species still remains fairly abundant around South Georgia
(Sts. 1125 and 1127) at the end of the summer.
The line from South Georgia to the pack-ice edge in 69° 22’ S, 9° 37:5’ E, taken in
March, passes throughout its length through Weddell Sea water. As already explained the
western stations on this line (Sts. 1138-47; Fig. 25) were taken in water flowing north-
eastwards out of the Weddell Sea, while the more easterly stations (1148-53) were taken
in the East Wind Drift current flowing westwards into the Weddell Sea. St. 1148 lies in
the area of divergence between these two masses of water. At St. 1142, as already
explained (p. 307), there appears to be a tongue of warmer water moving southwards,
since at this station the average temperature between 0 and 100 m. 1s above 10° C. (Fig. 7),
while at all the stations south of it it is less than o° C. All the catches on this line were
small, less than 500 individuals, as is usual in Weddell Sea water, except at the warmer
station (1142) at which over 1000 individuals were taken. This station corresponds in
position with St. 807 (Fig. 1a), taken in mid-January in the preceding season. The
catch in the two hauls combined at that station was 520 individuals. In January 1932,
however, the southward movement of warm water in this area was less pronounced than
in March 1933 and extended only to St. 806 at which 1104 individuals were taken.
Fig. 15 shows the distribution of R. gigas based on its percentage of the copepods in
RHINCALANUS GIGAS 313
the catches. It is again evident that while the Drake Passage was an area where R. gigas was
the most important species of copepod in the fauna(75 per cent and over), the Weddell Sea
was an area where it made up only a small proportion of the fauna. At the stations in the
South Sandwich-South Georgia area with a temperature lower than 0° C. it comprised less
than 25 °/., of the total Copepoda and at all stations with a temperature less than — 1-0° C.
less than 15 per cent of the total. It will be seen immediately that there is a striking
difference between the percentage distribution (Fig. 15) and the numerical distribution
(Fig. 14). In the season 1931-2 the two figures for the numerical and the percentage dis-
tribution (Figs. 8, 9) resemble one another fairly closely. Throughout the whole of its area
of maximum abundance in that year (catches of more than 10,000 individuals) R. gigas
was the dominant species of copepod, forming 75-100 per cent of the total copepod
catch. In the season 1932-3 R. gigas was the dominant species of copepod in the Drake
Passage (Fig. 15), but farther east between the Falklands and South Georgia it formed
only 50~75 per cent of the catch at several stations where more than 5000 individuals
were taken in the two hauls together. At St. 1025, where more than 10,000 individuals
were taken, it formed less than 50 per cent of the catch. It is evident that in the northern
and eastern part of the area of abundance in the season 1932-3 species of copepod other
than R. gigas were present in larger proportions in the catches than at corresponding
stations in the preceding season. Thus at Sts. 1019, 1023, 1025 and 1029, between the
Falklands and South Georgia (Figs. 2a, 15), species other than R. gigas formed between
25 and 50 per cent of the copepod fauna, while at Sts. 750, 751 and 788, which are as
nearly as possible the corresponding stations in the previous season (Figs. 1a, 9), species
other than R. gigas formed less than 25 per cent of the copepod fauna. Similarly, at the
beginning of December, north of South Georgia at Sts. 1054, 1056 and 1063 (Figs. 2a, 15),
the species was a somewhat less important constituent of the copepod plankton than in
this locality at the same time in the previous season. At Sts. 1054, 1056 and 1063 it formed
less than 50 per cent of the total copepod catch, but in 1931-2 at St. 774 it formed more
than 75 per cent and at St. 775 about 50 per cent of the catch. It is not proposed here to
deal with the distribution of other species of Antarctic copepods, but it may perhaps be
mentioned that at Sts. 1019 and 1023, near the Falklands, the proportion of warm-water
species, characteristic of the sub-Antarctic zone, was higher than in the same region in
the preceding season (Sts. 750 and 751). Conversely, at St. 1029 (Fig. 2a) the proportion
of cold-water species, characteristic of the colder waters of the Weddell Sea, was higher
than at St. 788, which corresponds in position with St. 1029, in December 1931. There
is a difference in date between Sts. 1019 and 750 of three weeks (g. xi. 32 and 30. xi. 31),
between Sts. 1023 and 751 of about a fortnight (16. xi. 32 and 1. xii. 31) and between
Sts. 1029 and 788 of over a month (19. x1. 32 and 2r. xii. 31). The higher proportion
of warm-water species between the Falklands and South Georgia in mid-November 1932
(Sts. 1019, 1023 and 1025), in contrast with that at the end of November and the be-
ginning of December 1931 (Sts. 750 and 751), may probably be correlated with the more
southerly position of the isotherms in 1932-3 than in 1931~2 (Figs. 5, 6). As we have
already seen (p. 303) Deacon found the season 1931-2 to have been colder and “‘later”’
314 DISCOVERY REPORTS
than the season 1932-3, and this has been suggested as a possible explanation of the late
ascent of Rhincalanus to the surface in the former season. We now see that this same
cause may account for the difference in the composition of the copepod fauna generally
at the beginning of the second season of the commission. The higher proportion of cold-
water Weddell Sea species at St. 1029, however, may be accounted for by the fact that
St. 1029 was taken in the tongue of Weddell Sea water which pushes northwards west
of South Georgia towards the Falklands (Fig. 6), while St. 788, in December 1931, was
taken in the Bellingshausen Sea current. St. 1066, taken in the middle of December 1932
near the western end of South Georgia, and the three stations, 1083, 1085 and 1088
(Fig. 2a), taken at the end of that month between South Georgia and the South
Orkneys, seem to show that the proportion of R. gigas increased in the copepod fauna
towards mid-summer in the region west and south-west of South Georgia. This is
indicated in Fig. 15 by a repetition, farther east, of the 75 per cent line. A comparison of
the isotherm charts for the first and second halves of the season 1932-3 (Figs. 6, 7)
reveals a southward and eastward movement of the isotherm lines in this region which
would, no doubt, be responsible for an increase in the proportion of R. gigas in the
fauna and a corresponding reduction in the proportion of cold water species character-
istic of the Weddell Sea.
VERTICAL RANGE AND DIURNAL VARIATION
There is no evidence from the hauls under consideration as to the depths below the
250-m. line to which Rhincalanus may extend. Hardy and Gunther (1935, p. 141), how-
ever, write of this species during the summer months: ‘‘ It was most abundant between
50 and 250 m. and was not taken at levels below 750 m.’’ We have seen, however, that
the area of abundance of the species almost certainly descends below 250 m. during the
winter, and Mackintosh (1935) has shown that the winter level of the species lies be-
tween 500 and 1000 m. Schmaus and Lehnhofer (1927, table c) record the species in a
vertical haul in the South Indian Ocean between 1900 and 2500 m.!
The hauls which form the subject of this paper were taken in a great many different
places and at a great many different times and do not provide evidence as to the vertical
diurnal movements of R. gigas. Hardy and Gunther (1935, p. 241, fig. 109) have, how-
Since the above was written a series of hauls was taken with the 7o cm. silk net towed obliquely
at various depths at several stations along the ice edge south of the Indian Ocean during November and
December 1935. The catches of Rhincalanus gigas taken in these hauls are tabulated below.
|
St. Date Depth Latitude Longitude No. of R. gigas
1935 m.
1642 gp 2a! 158-o He Goes || OG. HeHey We 1524
1636 | 30. xi 380-T50N a 5749-29-45 23-0. 312
nO || Ad, ss! 580-400 57 155704 San OE wAO;0) b. 480
1633 | 29. xi | 1100-875 Oma 5 7a Soule OmO 7. OME. 268
1639 | 2. xii | 2400-1150 | 58° 35-0’S. | g2° 06:2’ E. 211
RHINCALANUS GIGAS 315
ever, shown that R. gigas exhibits no diurnal vertical migration, but that there seems to
be a tendency for the species to occur at a higher level during the afternoon towards the
end of the hours of daylight (p. 242, fig. 112).
SUMMARY
1. The area of greatest abundance of R. gigas, in which the species was most abundant
both numerically and proportionately, in the Falkland Sector during the summer
seasons 1931-2 and 1932-3, lay in the Drake Passage and in the South Atlantic Ocean.
In 1931—2it occupied the Bellingshausen Sea current south of the Antarctic convergence,
but in 1932-3 it extended north of the convergence into sub-Antarctic water in the
Drake Passage and between the Falklands and South Georgia (pp. 294, 310).
2. This area of abundance is in striking contrast with the comparative scarcity of the
species in the Weddell Sea current (pp. 296, 297).
3. In the South Atlantic the limits of the area of greatest abundance were the Ant-
arctic convergence on the north and the o° C. isotherm, calculated from the average
temperature of the surface 100 m., on the south. In the Scotia Sea, where the influences
of the Bellingshausen Sea and Weddell Sea currents mingle, the southern limit of the
area of abundance was less certainly fixed, but lay somewhere between the o and 1-0°
isotherms. In the Drake Passage the southern limit of the area of abundance was not
defined in the season 1931-2. There was a great abundance of the species in water colder
than — 1-5° C., which was perhaps due to the upwelling of warm deep water along the
Antarctic continental shelf. In the season 1932-3 the northern limit of the area of
abundance was not strictly defined in the Drake Passage and South Atlantic but seems
to have been more or less coincident with the 5:0° isotherm. The southern limit in the
Drake Passage was the — 1:0°C. isotherm (pp. 294, 310).
4. The species occurred in fair abundance at the stations taken in sub-Antarctic
water in the South Atlantic during both seasons. At the end of both seasons, however,
it became restricted to the Antarctic Zone, and was taken in very small numbers in sub-
Antarctic water (pp. 298, 311, 312).
5. In the winter months around the Antarctic Continent a progressive diminution of
the catches in the surface 250 m. was found, together with the restriction of the species
to the Antarctic Zone. By mid-winter R. gigas had almost disappeared from the catches,
and in September in the South Pacific it had disappeared completely. Observations for
July and August are lacking. The species reappeared in the surface 250 m. in October
in the western Drake Passage (pp. 299, 301).
6. A study of the proportion of the combined catches taken in the upper and lower
nets strongly suggests that R. gigas spends the summer months within the surface
too m. and descends in about April to a level between 250 and 100 m., while in May it
sinks below the 250-m. lineand remains there until October, when it reappears between 250
and 100m. In November it regains the surface. Thus this species undertakes seasonal
vertical migrations similar to those found for several species in the northern hemisphere.
Its habitat during the summer months is thus the northward-flowing Antarctic surface
water and during the winter months the southward-flowing warm deep water (pp. 301-2).
316 DISCOVERY REPORTS
+. Certain differences in the distribution of the species in 1932~3 from the distribu-
tion in 1931-2, such as the scarcity of the species in the western Drake Passage in
October 1932, have been ascribed to the fact that the investigations were carried out a
month earlier in the spring of 1932-3 than in the spring of 1931-2, before the spring
ascent of the species had been completed. Otherwise the differences in distribution
during the two seasons were not very great. The catches generally were smaller in 1932-3
than in 1931-2 (pp. 308-11).
8. As the season advances there is, so far as can be ascertained, a general diminution
in the catches of R. gigas, with a tendency for the area of maximum abundance to be-
come concentrated in Antarctic water around South Georgia rather than in the Drake
Passage (p. 312).
g. The comparatively small Rhincalanus population in the Weddell Sea enters that
area by means of the southward-flowing warm deep water from the South Atlantic or
South Indian Oceans. In the latter case it is carried into the Weddell Sea in the deep
water of the East Wind Drift current flowing westwards into the Weddell Sea south of
66° S along the coast of Coats Land (pp. 304-7).
10. The species appears to be carried upwards to the surface out of the deep water by
some unknown factor in the course of its passage around the Weddell Sea. It is suggested
that the upwelling of warm water in the centre of the cyclonic system may perhaps be
the cause of this (p. 306).
LIFE His TORY
APPROACH OF THE SPAWNING PERIOD
The indications of the approach of the spawning period in any copepod population
are:
(1) The appearance of large numbers of females with ripe gonads.
(2) The appearance of male adults in large numbers in the catches.
(3) The approach of the stock to maturity as indicated by the disappearance of
juveniles from the population.
These indications may be discussed separately.
APPEARANCE OF RIPE FEMALES. No detailed observations of the numbers of ripe fe-
males in the catches were made during the season 1931-2. During the season 1932-3,
however, a selection of samples of 50 or less adult females from a number of stations was
preserved and examined for the presence of ripening eggs in the gonads. The samples
selected cover the period from the end of October to the middle of March, but owing to
the fact that the ship was engaged on hydrographic survey during January there are no
observations for that month.
R. gigas is transparent and in the female the gonads can be clearly seen occupying a
saddle-shaped area postero-dorsally beneath the carapace (Fig. 17). Two long oviducts
run back from the ovary on either side to open on the genital segment. In the yet im-
mature female the genital cells are transparent and almost invisible in the dorsal and
RHINCALANUS GIGAS 317
posterior part of the’ saddle-shaped ovary. The oviducts appear as a fine cord of trans-
parent cells on either side of the body (Fig. 17 a). As maturity approaches the anterior
and ventral border of the saddle-shaped ovary takes on a deep brown colour in the pre-
served specimen and can be seen to be made up of a line of large dark cells each with a
circular nucleus (Fig. 17 5). This border of enlarged cells, the young eggs, extends from
the most anterior part of the ovary under the carapace along the ventro-lateral margin
of the gonad and oviducts to the genital opening. The ripening eggs become larger and
eee
be
tg.
eaten ates
or
an
a d
Fig. 17. Rhincalanus gigas. Adult females. Condition of the ovaries. a. Unripe. 6. Maturing. c. Ripe.
d. Spent
darker as maturity approaches, and, when about to be shed, they appear as very large
dark circular, discrete cells, resembling a string of beads, forming a conspicuous row along
each side of the thorax from the most anterior part of the ovary in the centre of the
carapace to the genital opening (Fig. 17 c). ‘Towards the end of the season many females
appeared in the samples in which the only sign of a gonad was a thin transparent string
of tissue on either side of the posterior segments of the thorax (Fig. 17 d). No cell limits
were distinguishable in this, and it was assumed that these were “‘spent”’ females which
had shed their eggs.
D XIII 6
318 DISCOVERY REPORTS
It was found impossible to do more than draw up a very rough classification of the
females examined. No very definite distinction could be made between unripe females,
in which the gonads were transparent, and maturing females, in which the ripening eggs
could be detected as a dark border to the gonad. This dark border appears first as a line
along the margin of the gonad only less transparent than the gonad itself. Similarly it
was very often difficult to distinguish between maturing females in which the eggs were
almost ready to be shed and ripe females in which the eggs were evidently fully ready to be
shed. Four classes, then, of adult females have been very roughly distinguished: namely,
unripe females, maturing females, ripe females and spent females. It is possible, how-
ever, that among the “‘unripe females” are some in which the incipient dark border of
ripening eggs could be seen, while the class ‘‘ maturing females”’ is a very indefinite one
and includes all those in which the eggs form a dark border to the gonad. It may,
therefore, include many ripe females. Similarly, the class “ripe females” may include
many very nearly mature specimens in which the large bead-like eggs could be seen in
the oviducts but were not really ready to shed.
The numbers of each of these four classes of adult females found in each sample
examined have been tabulated below together with the percentage of each class in the
total sample. The number of females examined was 50 in most instances, but it will be
seen that at several stations, at which the major part of the catch consisted of juveniles,
considerably less than 50 females were examined.
Degree of maturity of adult females of Rhincalanus gigas,
October 1932 to March 1933
| nripe / in Ripe Spent
Date St. SpE we: | ee ee | Z j= :
m. | examined ]
| Now 26) No: oe IN@s || 6 No. OF
1932 | |
24.x | 984 | 240-100 | 46 | 20 80 S| 2a |
26. x 988 | 880 | 60 | 29 | 483 | 26 | 433 | 5 | 843 —- —
224— 74 Om po en ec6 eee Ss 66 | 4 8 - —
27am 990 276-100 50 37 74 13 26 | a
28.x 992 | 270-110 50 20 | 40 30 60
I. xi 1000 300-110 50 47 94 3 6 = == = a
g. Xi IOIQ | IIg-o 50 8 16 | 24 48 18 36 = =
13. Xi 1021 120-0 40 32 80 a] 16 I 4 == =
1g. Xi 1029 | 100-0 50 OM ats 27 54 15 30 = =
21. xi 1033 113-0 50 16 32 28 56 7 14 > =
4. xii 1056 100-0 50 I 2 41 82 13 26 = =
II. xii | 1063 334-114 32 5 15°6 17 | 53-4 5 15-6 5 15°6
31. xii 1085 146-0 50 20 40 13 26 3 6 ts ze
£933
7-H 1116 110-0 40 7 17°5 25 62-5 a — 8 20
20. ii 1122 70-0 28 4 14°3 18 | 64:3 3 10°7 3 10°7
21. il 1125 97-0 50 26 52 6 32 3 8 16
23.11 1127 100-0 20 4 20 15 75 = re t 5
Q. ili 1148 117-0 15 6 (46) 9 (54)
e 330-130 16 16 | (100) = = —s = a =a
10. iil II50 gI-o 5] 7 |(100) = = = aad = 7a
RHINCALANUS GIGAS 319
Four samples were examined from the line taken across the western Drake Passage in
October. ‘The three samples from Sts. 988, ggo and gg2 show a high percentage of un-
ripe or maturing females or of both. At the other station, 984, nearly all the females
were unripe. ‘This was the most northerly station on the line and was in sub-Antarctic
water with an average temperature higher than 5-0° C.
Five samples were examined from stations taken in the month of November. At the
most southerly (St. 1000), at which the average temperature for the surface 100 m. was
lower than — 1°5° C., and at the most northerly (St. 1021), at which the temperature was
again higher than 5-0° C., nearly all the females were unripe. At the two stations in the
area of maximum abundance of the species (Sts. rorg and 1029) 36 and 30 per cent re-
spectively of ripe females were found and the remainder of the two samples consisted of
maturing females, many of which, at St. 1029 at any rate, were almost ripe. At St. 1033
again, taken in Weddell Sea water colder than 0° C., the majority of the adult females
were still maturing and 32 per cent were unripe.
Three samples from stations taken in December were examined, two from Bellings-
hausen Sea water (1056 and 1063) and one from Weddell Sea water (1085). At St. 1056,
very early in the month, the sample consisted mainly of maturing females, with 26 per cent
which were ripe or nearly ripe. At St. 1063 in the middle of the month and St. 1085 at
the end of the month spent females made their appearance. ‘The remainder of the sample
from St 1063 consisted of maturing females and ripe and unripe specimens in equal
proportions. At St. 1085 there was a large proportion of unripe and maturing specimens,
but while the proportion of “spent” females was high that of “‘ripe”’ females was
very small. The population at this station, which was taken in Weddell Sea water,
almost certainly contains a high proportion of females from the Weddell Sea area itself.
Thus the population is probably a mixture of matured and “spent” stock belonging
to the Bellingshausen Sea water and a still immature stock from the Weddell Sea water.
Thus far the table indicates that the eggs were shed at the end of November and the
beginning of December in the waters of the Drake Passage and western Scotia Sea in
which the average temperature for the surface 100 m. lies between o and perhaps 3-0
or 4:0°C. At stations where the surface temperature is lower than 0 or higher than 3-0 or
4:0°C. the ripening of the eggs appears to suffer delay (Sts. 984, 1000, 1021, 1033 and 1085).
There are, unfortunately, no observations for January, but four samples were ex-
amined from stations taken in February. At St. 1116, in the Drake Passage, a high
proportion of the sample consisted of spent females, but the proportion of maturing
females was also high. At Sts. 1125 and 1127 at the end of the month, between the
Falklands and South Georgia, the samples consisted mostly of unripe females (1125) or
maturing females (1127). The maturing females at these stations in February must
belong to a new generation resulting from eggs shed earlier in the summer, since ripe
females appeared in this region in November. Similarly at Sts. 1148 and 1150 in March,
taken in the East Wind Drift current flowing into the Weddell Sea, the unripe and
maturing females, of which the samples consisted, must also be an advancing new
generation of adults.
320 ; DISCOVERY REPORTS
APPEARANCE OF ADULT MALES. The small proportion of adult males in the catches of
oceanic copepods is well known. Ottestad (1932) and Wolfenden (1911) drew particular
attention to the absence of the mature male from the collections of Calanus acutus made
by the ‘ Vikingen’, ‘Discovery’, ‘Gauss’ and ‘ Belgica’. Several authors, however, have
found that at certain short periods during the year the proportion of male to female
adults suddenly increases very greatly. The period of increase is followed by a much
longer period during which males are almost absent or present only in small numbers.
This sudden appearance of males was usually found to precede the appearance of
nauplii and young stages, and to follow or coincide with the appearance of females with
ripe eggs in the oviducts. Thus Sémme (1934, p. 77) found males of C. hyperboreus
“only exceptionally outside the period 15. xii to 15. ii, but within that period even a
short time with a surplus over the number of females... .' Towards the end of the time
when females with eggs in the oviducts are found, that is to say just before spawning,
they (male adults) are already found to be present in very small numbers.” Sdémme ex-
pressed the opinion that the adult male has a very short life period, perhaps less than
two months. Farran (1927) also found males of C. finmarchicus in excess of females only
during the month of January, but a fairly high proportion also during May. He was
unable to relate their appearance to that of ripe females. Ruud (1929) found a high
proportion of adult males of C. finmarchicus present in May 1926 and 1927 at a number
of stations taken off the coast of Norway between February and July of those years.
Their appearance preceded the May-June spawning. Paulsen (1909) found large num-
bers of adult male C. finmarchicus appearing in June off Iceland, in sharp contrast to the
small numbers taken in the preceding and following months. He correlated their ap-
pearance with the spring period of reproduction.
Table V a-c and Fig. 18 show the percentage of males among the adults of Rhin-
calanus gigas taken in the Falkland Sector during the seasons 1931-2 and 1932-3. Those
stations at which the number of adults was too small to give true percentage figures have
been omitted from the figure and are placed in brackets in the table. A few stations
taken in April in the south Indian Ocean have also been included in the table and in the
figure. In the season 1931-2 the proportion of males rose suddenly in the middle of
December from a maximum of less than 1o per cent of the adults in the catch, and an
average of less than 5 per cent, to a maximum of 32°8 per cent. The figure suggests per-
haps that the proportion of males decreased more slowly than it increased and continued
high throughout December. In the season 1932-3 the proportion of males to females
increased more slowly from early in November and reached its maximum in the first
week in December, continuing high throughout that month. The appearance of adult
males thus coincides with the time of shedding of the eggs—so far as that can be fixed
from the scanty data available. It will be seen later (p. 326) that nauplii made their
appearance in the catches in the season 1931-2 in the middle of December, when adult
males reached a maximum, so that fertilization, shedding and hatching of the eggs must
take place within a very short time. It is not possible to know when the nauplii taken
in the middle of December were spawned, but it seems unlikely that they represent the
RHINCALANUS GIGAS 321
earliest nauplii to be hatched, since nauplii never made their appearance at any sub-
sequent time during the season, and, as will be seen (pp. 326, 328), young copepodites
were taken at the end of the first week in January. It is thus at least evident that a very
short time, perhaps not more than a week, elapses between the shedding and hatching
of the eggs.
It will be seen from Table V a—c that the proportion of males is almost always higher
in the deep nets (250-100 m.) than in the shallow hauls (100-0 m.). At many stations
where males occurred in the lower haul none was taken at all in the upper net, and,
during the maximum period for adult males, the percentage of them in the upper nets
underwent no increase. It is evident that adult males are more restricted in vertical
%
40
R
tS es X SEASON 1931-32
30 hg IS © SEASON 1932-33
i now wee
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5 10 15 20 2 5 lo & 202 5 10 15 20 25 5 10 15 20 25 855 152025
os OCTOBER NOVEMBER DECEMBER JANUARY FEBRUARY
40
30
20
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5 x= SS SS
ERM SEOneS meno M OM SncONcoESmIUMI5:2OmeS 5 10 6 2025 5 10 5 20 2
MARCH APRIL MAY JUNE JULY
Fig. 18. Rhincalanus gigas. Adults. Percentage of males in total adults (upper and lower hauls combined).
Falkland Sector, 1931-2 and 1932-3 and Indian Ocean Sector, April 1932.
distribution than females, which occurred in equal abundance in both nets. Paulsen
(1909) found the adult males of Calanus finmarchicus at greater depths than the females,
and Stormer (1929, p. 25) wrote: “The adult (C. finm.) female occurs for the most part
at 100-50 m. or scattered throughout all depths. The adult males are found at 300-50 m.”
Male copepodites of Rhincalanus gigas in stage v are nevertheless found equally abun-
dantly in both nets, so that restriction to layers below the roo-m. level is peculiar to the
adult. If this is the case then only those females which are below the 1oo-m. level during
the summer time will be fertilized. Nauplii and young forms, as Stérmer found for
Calanus finmarchicus, are taken at the surface, so that either the fertilized females must
rise to the surface to shed their eggs or the eggs must rise to the surface after they are
shed. The curves showing the composition of the Rhincalanus stock in stages, to be
studied in the following sections of this paper, perhaps hint that the adult females
322 : ‘DISCOVERY REPORTS
descend below the 1oo-m. level before being fertilized, since at the majority of the
stations taken in the Drake Passage and Scotia Sea (Figs. 19, 20) during the spring
(1931-2), the proportion of adults is a good deal higher in the lower than in the upper
nets especially after the end of November (p. 326). There is no marked difference at
any time in the proportion of stage v female copepodites in the upper and lower nets.
As a comparison with the figures given in the above section for adult males in the
Falkland Sector during the summer seasons 1931-2 and 1932-3, the following figures of
Schmaus and Lehnhofer (1927) may be quoted giving the numbers of adult males and
females collected by the ‘ Valdivia’ between November 29 and December 10, 1898, from
the region south of South Africa. The percentage of males which these figures represent
has been added.
Date No. of No. of Males
1898 females males %
29. xi 348 28 74
2. Xil 634 82 11-4
5. xii 153 20 II°5
7. xii 125 12 8°75
These hauls were taken with a vertical net 1-5 m. in diameter, fished from depths
between 1000 and 2000 m. to the surface. The percentages are about the same as those
found for the same time of year in the Falkland Sector in 1932, but slightly higher than
those for December 1931.
‘THE APPROACH OF THE STOCK TO MATURITY. The discussion of the composition of the
Rhincalanus stock in stages, which forms the following section of this paper, shows that
in the season 1931-2 the population reached maturity in December and that adults
began to predominate in the catches from about the end of the first week of that month.
In 1932-3 the population would seem to have become mature earlier. Adults pre-
dominated at all the stations from the middle of November onwards. Most of the
stations at the end of November and the beginning of December, however, were taken
in Weddell Sea water. In the first season, 1931-2, there were no observations from
December 21 to January 6, but on January 7 (St. 796) and on January 10 (Sts. 802 and 803)
adults were very few and a new generation had made its appearance and predominated
in the catches. Nauplii were taken on December 18 (St. 778). In the second season,
1932-3, observations were lacking for January and the new generation was taken in
February (Sts. 1116, 1117, 1125, 1127).
COMPOSITION OF THE STOCK OF RHINCALANUS GIGAS
The only examination of the population of R. gigas in Antarctic waters from the view-
point of the composition of the stock in copepodite stages which has yet been made is
that of Ottestad (1932).! This author examined the material from fourteen stations taken
1 A further paper by Ottestad has appeared while this report was in the press, see pp. 293 and 356.
——
RHINCALANUS GIGAS 323
in the season 1929~30 by the ‘ Vikingen’ and one taken by the ‘ Norvegia’ in 1928. Some
of these stations were taken in water flowing out of the Weddell Sea between the South
Sandwich Islands and Bouvet Island, and some in Weddell Sea water south of the South
Sandwich Islands and east of the South Orkneys.
The conclusions at which Ottestad arrived from the data at his disposal will be
seen to be largely confirmed in what follows. He found that two age groups were dis-
tinguishable in the population taken at the earlier ‘ Vikingen’ stations at the end of
other, the older one, of stages iv, v and vi. In the latter half of December the older of
these two groups had disappeared. At the Norvegia station, taken in mid-January 1928,
the older group had disappeared and the younger group had advanced to stages iv, v
and vi. Ottestad concluded (p. 51), since he never found nauplii or stage i at any of the
stations taken by the ‘ Vikingen’, “that the stock existing in the Weddell Sea is due to an
invasion from another spawning area”. He suggested that Rhincalanus spends the
winter in deep water, rising to the surface before spawning in the spring, and is carried
into the Weddell Sea by the “Antarctic Intermediate water” (warm deep water—
Deacon, 1933). Of these two last assumptions we have already seen that the former
is very strongly supported by the data collected by the‘ Discovery II’. The latter assump-
tion we also believe to be correct, though Rhincalanus is probably carried into the Wed-
dell Sea to a greater extent by warm deep water originating in the South Indian Ocean
(East Wind Drift current) than by water originating in the South Atlantic.
Finally, Ottestad writes (p. 51): “‘ No renewal of the stock takes place in the Weddell
Sea as the mature stock disappears without previously spawning. . .neither is it possible
to prove that spawning of this species takes place in the Weddell Sea.”
In the present work the copepodite stages were identified according to the description
of Schmaus and Lehnhofer (1927). There are, as usual, five copepodite stages between
the nauplius and the adult, which is counted as stage vi. Stages i, iv and v were of
frequent occurrence in the hauls, but stages i and ii occurred less frequently and only,
presumably, when present in the water in such abundance that they could not all
escape through the meshes of the stramin net. Nauplii occurred even less frequently
and, again, only presumably when present in immense numbers in the water. It can
hardly be expected, therefore, that the numbers of the younger copepodite stages taken
in these hauls will be very accurate or give more than an approximate picture of the
condition of the population at the stations where they occur.
Drake Passage and South Atlantic Ocean, November 1931
(Fig. 19, Table VI a)
Fig. 19 shows the percentage of the various copepodite stages in the catches in the
upper and lower nets at stations in the Drake Passage and western Scotia Sea from the
middle to the end of November 1931. At the end of November the dominant stages are
iv and v at nearly all stations in the Drake Passage. However, it will be noticed that at
stations north of the Antarctic convergence (Sts. 725-7, 750 and 751, at the beginning
324 ; DISCOVERY REPORTS
of December), stage iv is almost absent, stage v is dominant and adults are present in
large numbers. In some of the hauls from these stations north of the convergence adults
(stage vi) are even dominant. At stations south of the convergence (Sts. 731, 733, 739,
741 and 745), stage iv is usually present in fairly large numbers, especially in the lower
hauls, but stages younger than this are absent. At Sts. 735 and 737, the most southerly
of the stations in the Drake Passage, fair numbers of stage iii were taken (at St. 735 more
than 20 per cent in the lower net). Thus the stock north of the convergence is definitely
older than the stock south of it, and the stock in the warmer Antarctic water is apparently
older than that in the coldest Antarctic water. Now the stock found at these stations at
the western end of the Drake Passage in November 1931 was in the course of or had just
completed its spring ascent to the surface. It had just passed the winter at a depth
below 250 m. Further, several considerations lead one to believe that the young stages
(stage 111) found at the edge of the ice do not result from a recent spawning. In the first
place they are not present in sufficient quantities to indicate a recent spawning. At St.
735 only 22-0 per cent stage iv and 11-7 per cent stage iii were found in the two hauls
together, and at St. 737 only 26-0 and 9-7 per cent of stages iv and iii respectively.
Stage 11 was present at each station in very small numbers, and no stage i or nauplii were
found. In the second place, we have seen from figures for the following season that the
adult females at this time of year are not yet ripe and no males had appeared. It seems
evident, then, that in the coldest Antarctic water, with an average temperature less than
— 1°5°C., the stock in the spring, which had just passed the winter below 250 m., con-
tained a proportion of individuals which had not developed beyond stage 11. ‘The stock
in the warmer Antarctic water (average temperature below about 3-0° C.) appears to
have developed as far as stages iv and v by the spring and that in water north of the
convergence as far as stages v and vi. The population in all these three classes of
water probably results from a mid-winter spawning, as we shall see later (p. 338),
and it must be assumed either that the stock in Antarctic water with an average
temperature less than — 1-5° C. has been spawned later in the winter than that in
warmer Antarctic water (average temperature below about 3-0° C.), or else that it was
spawned at the same time as the stock farther north but that its rate of development
has been retarded. Similarly the stock in the warmer Antarctic water must either have
been spawned later than the stock north of the convergence or else have developed
more slowly during the winter months.
In the main the stock curves of the population in the western Drake Passage in
November 1931 show that the species rises to the surface from its winter level prin-
cipally in stages iv and v, so that one may say that Rhincalanus gigas, like other species
of oceanic Copepoda (S¢mme, 1934, Calanus finmarchicus and C. hyperboreus ; Nicholls,
1933, C. finmarchicus; Campbell, 1934, C. tonsus and Euchaeta japonica; and others)
spends the winter months in these two stages.
At the stations in the eastern Drake Passage and in the South Atlantic near the
Falklands at the end of November stages iv and v were predominant and the pro-
portion of adults was high in the lower nets.
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326 : DISCOVERY REPORTS
Scotia Sea and South Georgia, December 1931 (Fig. 20, ‘Table VI 6)
On the line of Sts. 751~759 (Western Scotia Sea), at the beginning of December, con-
ditions were much the same as on the line of Sts. 743~750 at the end of November (Eastern
Drake Passage). Stage v still predominated and the proportion of adults was high,
except at St. 753.
Early in the season, during the month of November, many of the stations show a high
proportion of adults in the upper nets (Sts. 727, 735, 737, 741), and at some others,
notably Sts. 726 and 739, the proportion of adults was approximately equal in both the
upper and lower nets. In those, however, which were taken after the end of November
and in early December in the Drake Passage and Western Scotia Sea (Sts. 743-761), the
proportion of adults is higher in the lower hauls than in the upper. This, it has been
suggested (pp. 321, 322), may represent a descent of the adult females to a fertilization
level coincident with the appearance of a high percentage of adult males in the layers
below 100 m.
At the end of the first week in December (St. 763) stage vi (adults) began to pre-
dominate in the catches. The appearance of the stock curves for the lower hauls at Sts.
763-768 and 775 is perhaps partly due to the appearance of large numbers of adult males
in the lower hauls (Table Va). In the upper hauls at these stations, however, adult
females were overwhelmingly predominant. Sts. 763~768 were taken in water flowing
out of the Weddell Sea, so that it is possible that the population at these stations is a
mixed one, consisting partly of the stock from the Drake Passage and partly of that
from the Weddell Sea. At Sts. 774, 775 and 776, which were taken in the Bellingshausen
Sea current, unmixed with water from the Weddell Sea, the stock is approaching
maturity, but contains more stage v than that at the stations in Weddell Sea water south
of South Georgia. At St. 776, immediately north of the convergence in this area, there
is a surprisingly high proportion of stage iv in the surface haul.
South Atlantic Ocean, East of South Georgia, mid-December 1931 to
mid-Fanuary 1932 (Fig. 21, Table VI c)
The stations east of South Georgia, taken in the middle of December and the middle
of January, appear to show several different stocks. Firstly there is a stock consisting
almost entirely of young forms up to stage iii. These are found at South Atlantic stations
in water of Bellingshausen Sea origin (Sts. 796, 802 and 803). In addition to these three
stations there is St. 778 (18. xii. 31) at which we find two age groups in the surface haul
—an old one consisting of stages v and vi and a young one consisting of nauplii, stages 1,
ii and iii. The surface net at this station was choked with diatoms so that it is not im-
possible that it took an unduly high proportion of very young forms. On the other hand,
at St. 780, taken the next day in Weddell Sea water, the surface net was similarly choked
with diatoms and no young forms were taken at all. Abundant diatoms were also taken
in the 1-m. nets at several other stations at this time (Sts. 806, 807, 808 and to a lesser
extent 809), but in these again no very young forms were taken. ‘The presence of nauplii
and very young stages at St. 778 may therefore legitimately be taken to indicate that
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328 DISCOVERY REPORTS
spawning had recently taken place and was not due solely to the choking of the meshes
of the net. The population at Sts. 796, 802 and 803, then, very probably belonged to the
STATIONS — 778 796 802 803
DATES — 1a-xXil 7-\ 1IO-| 1o-|
AVERAGE TEMPERATURE OF SURFACE 100m I°— 3°C
UPPER NET [l00m - Om.APPROX. |
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Fig. 21. Percentage of copepodite stages of Rhincalanus gigas in 1-m. nets. South Atlantic Ocean east of
South Georgia, December 1931 to January 1932. (See Table VI c.)
same stock as the young forms at St. 778, which had grown into stage iii in the inter-
vening three weeks (18. xii. 31 to 7. i. 32). It seems to be quite a legitimate supposition
that nauplii and stages i and ii should have grown into stage iii in this short time. In
RHINCALANUS GIGAS 329
the northern hemisphere the rapidity of growth of the summer generation of copepods
has frequently been commented upon. Ruud (1929) found that about seven weeks
elapsed between the maximum for nauplii and the maximum for adults of Calanus
finmarchicus off the coast of Norway, and gave about three months as the time required
for the complete life cycle, including the embryonic development. Lebour (1916), from
Crawshay’s cultures at Plymouth, gave only two months from the egg to stage v. The
population at Sts. 796, 802 and 803 had drifted probably from the region of South
Georgia in the West Wind Drift (Bellingshausen Sea current) since spawning. Atall these
stations (778, 796, 802 and 803) it will be noticed that the old parent generation was found
in the lower nets. The greatest number of the old generation was taken at St. 778 ; fewer,
with some of the new generation stage iv, at St. 796; more stage iv and fewer of the old
generation at St. 803, and very few of the old generation at St. 802. Thus the old generation
appeared to die out as it became carried away from South Georgia. It may also be noted
that the stock at St. 803 in the surface haul was slightly older than the stock at either
Sts. 796 or 802. It contained more stage iv and fewer stage ii and must be supposed to
have been spawned slightly earlier than the stock at Sts. 796 and 802. St. 803 lay be-
tween the 2:0 and 3:0° isotherms, while Sts. 796 and 802 lay between the 1-0 and 2-0”
isotherms. It looks, therefore, as though spawning had taken place somewhat earlier in
warmer water (2:0-3:0°) than in the colder water (1-0-2:0°).
We have now a picture of the spawning of Rhincalanus gigas taking place in this
season in the Bellingshausen Sea current in South Atlantic water east of South Georgia
probably in the first fortnight in December. No spawning seems to have occurred west
of the island at this time, since at St. 788, taken west of South Georgia in the third week
in December (Figs. 1a, 20), a maturing stock was still found with no young forms at all.
The spawning apparently took place earlier in water warmer than 2-0° C. than in water
with a temperature lower than this.
It appears that the spawning took place in Antarctic water, since at St. 776 (Figs. 1a, 20)
in the sub-Antarctic zone the population at this time consisted of stages iv, v and vi
with no trace of a new generation. It is hardly possible that the high proportion of
stage iv in the surface net at this station can represent the product of a recent spawning
since almost no stages younger than this were found and the remainder of the stock
consisted of stages v and vi. At St. 775, eighty miles farther south on the Antarctic side
of the convergence, the population also consisted of the old generation in stages v and vi.
It is perhaps worthy of note that evidence of spawning was found at the stations in the
area where Antarctic water from the Bellingshausen Sea comes into contact with water
from the Weddell Sea, but that no trace of spawning was found at this time in the same
water away from the influence of the Weddell Sea (Sts. 774, 775 and 788). As will be
seen later (p. 334) there was found in February between the Falklands and South
Georgia a very scanty population on the sub-Antarctic side of the convergence in
stage ili, which was judged to be the result of a very greatly diminished spawning
which took place in sub-Antarctic water much later than the main spawning in
Antarctic water.
330 : DISCOVERY REPORTS
There is no doubt that spawning takes place in any given locality at different
times in different seasons. In 1931-2 it took place east of South Georgia in the
first fortnight in December. In 1929-30, however, Ottestad found a young generation
December. The Vikingen stations were taken considerably farther east at this time than
the most easterly of the Discovery II stations in early January 1932. In the season 1929-30,
therefore, spawning must have taken place east of South Georgia somewhere about the
beginning of November. It is probable that the time of spawning depends on some
variable factor, and one may suggest, as the most likely one, the break-up of the pack-
ice and the southward movement of the isotherms in this area. The season 1929-30 was
an exceptionally mild one; the pack-ice was far south and there was no sign of it around
the South Sandwich Islands. In the season 1931-2 the pack-ice was north of the South
Orkneys at the end of the first week in December and around the South Sandwich
Islands probably in early January. It may be that the difference in the time of break-up
of the pack in the two seasons accounts for the difference in the spawning time of
Rhincalanus.
Weddell Sea, mid-December 1931 to mid-fanuary 1932
(Pig: 22, Table Vie)
We have now to examine the Rhincalanus populations at the remaining stations in the
South Atlantic area. They all lie in the Weddell Sea current, and it will perhaps be best
to consider them in relation to the Weddell Sea as a whole.
At stations in the “‘oldest’’ Weddell Sea water (average temperature for 0-100 m.
between o and 1-0° C.)—Sts. 779, 795, 798, 806 and 808—the catches (except at St.
779) consist of stage v, with varying proportions of stage vi. No young forms were
found at any of the stations in the Weddell Sea, except at St. 804, where a fair propor-
tion of stage iv were taken in the upper net together with a very few stage 111. From this
fact one may conclude that before the end of January, at any rate, no spawning took
place in the Weddell Sea. At each of the stations in the “oldest”” Weddell Sea water
(o-1-0° C.) the larger proportion of the catch was in the lower nets and hence it may
be supposed, as already mentioned, that the population originated mainly from the
warm deep water of the South Atlantic or Scotia Sea, which here mixes with colder
Weddell Sea water at the surface above about 200-250 m. At these stations (Fig. 22) the
stock consisted predominantly of stage v. At the most westerly station (779) in the
‘oldest’? Weddell Sea water the stock consisted predominantly of adults. At Sts. 763,
765 and 768, taken in the Scotia Sea in water of Weddell Sea origin (Table VI 4,
Fig. 20), it must be assumed that the population in both nets is of mixed origin, since
a high degree of mixing takes place in this particular area. However, the main body of
the catch at these stations occurred in the upper nets, so that most of the population
sampled by them is perhaps derived from Antarctic surface water which has spent
some time in the Scotia Sea, since the water derived most recently from the Weddell
Sea will probably be concentrated in the lower stratum of the surface layer. Adults
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332 7 DISCOVERY REPORTS
predominated in the upper nets, and in the lower nets adults and stage v appeared to
predominate in about equal proportions. ‘The predominance of adults in the lower nets
at these stations, however, is largely due to the increased proportion of adult males.
Thus the Rhincalanus population of the Bellingshausen Sea current, when it became
carried into the colder Weddell Sea water where the temperature was below o° C.,
appears either to have been prevented from reaching maturity by the middle of January,
as at Sts. 795, 798, 806, and 808, or, as at Sts. 763, 765, 768 and 779, to have reached
maturity but failed to spawn.
At the stations in Weddell Sea water containing melting or recently melted pack-ice
(— 1-5-0° C.) the stock consisted mostly of adults with varying proportions of stage v. At
nly two stations did stage v predominate (Sts. 809 and 815), but at these the size of the
catches was possibly too small to give accurate percentages. At St. 804 a fair proportion
of stage iv was taken, possibly carried southwards in Atlantic deep water. At all these
stations in Weddell Sea water with a temperature below o° C. it seems probable, from
the complete absence of young stages, that we are dealing with a population which had
failed to spawn, and at Sts. 810, 812, 822 and 823—the most centrally situated in the
Weddell Sea—the scarcity of stages younger than stage vi (adult) is very striking. ‘The
population in this water (less than o° C.) is being carried northwards out of the Weddell
Sea in the north-easterly current, and it may be suggested that this is an over-wintered
stock, resulting from the previous winter’s spawning, which was carried into the
Weddell Sea by warm deep water of the East Wind Drift.
Finally we come to the stations in the East Wind Drift current flowing westwards into
the Weddell Sea south of 66° S (Sts. 815, 816 and 817). We find that the stock at these
three stations consisted of stages iv (at Sts. 816 and 817) and stage v (at St.815). Further,
the catches were entirely in the lower nets. This is a population which, from its age,
must have been spawned earlier on during the current summer somewhere to the east
off the coast of Coats Land. At any rate, since there are no signs of a parent generation,
it is reasonable to suppose that this stock had been spawned a considerable distance away,
perhaps outside the Weddell Sea; that it was the same stock, therefore, as that found
at Sts. 796, 802 and 803 and that it had been carried into the Weddell Sea by the
westward-flowing warm deep water of the East Wind Drift current originating in the
South Indian Ocean. It thus seems probable that the population at Sts. 810, 812, 822,
823 and perhaps 780 consisted of a similar stock carried into the Weddell Sea during
the preceding winter or even during the previous season, and the adults of which this
stock consisted must have been over six months or perhaps over a year old.
Weddell Sea and Eastern Scotia Sea, end of January 1932 (Fig. 23, Table VI c)
At St. 824 (27. i. 23; Fig. 1b) we again encounter a stock which was probably of mixed
origin, as was suggested for the population in this region during December (Sts. 766—
768, p. 330). It probably originated partly from the Bellingshausen Sea water of the
Scotia Sea and partly from the Weddell Sea. It consisted almost entirely of stages v
and vi—stage v in the upper and stages v and vi in the lower nets. It is probably similar
RHINCALANUS GIGAS
STATIONS — 822 823 824 825
DATES — 23-| 27-! e7-l 28a-l
AVERAGE. TEMP. OF
SURFACE !00m <-1-S°C.
@
© oe
@
Oo
4
je)
UPPER NET [lOO m—Om. APPROX]
nN
oS
60 NUMBERS
INSIGNIFICANT
LOWER NET [250m-100m APPROX]
(alnalieclienl
STAGES 23456239456 eat56 23456
333
Fig. 23. Percentage of copepodite stages of Rhincalanus gigas in 1-m. nets. Weddell Sea and Eastern Scotia
D XIII
Sea, end of January 1932. (See Table VI c.)
334 : DISCOVERY REPORTS
to the population found in the “oldest” type of Weddell Sea water (o—-1-0° C.) at the
beginning of the month (Sts. 795, 798, 806 and 808), and represents that the part of
the population of the Bellingshausen Sea current in the Drake Passage which had failed
to reach maturity by the end of January, through having drifted into Weddell Sea water
with a temperature lower than 1-0° C. At St. 825 (Fig. 15), however, we find the stock
consisting almost exclusively of stage iii. This must result from a fairly recent spawning
and part of the parent generation remains, particularly in the lower haul. It will be
noticed that the stock here in the Scotia Sea at the end of January is of the same age as
that found during the first week of the month at Sts. 796, 802 and 803 (Fig. 21). Now
the population sampled at St. 825 must result from a spawning which took place to the
south-west in the Scotia Sea in water of Bellingshausen Sea origin, where the tempera-
ture, according to the isotherm map (Fig. 5), may have been less than o° C. This
spawning, then, must have taken place, if the rate of development is the same in all
waters, at least three weeks later than that which took place east of South Georgia at
the end of December and which gave rise to the stock at Sts. 796, 802 and 803 (Fig. 21).
Alternatively the spawning took place at the same time, but the growth rate in the water
of lower temperature has been slowed down.
Falkland Islands to South Georgia, mid-February, 1932 (Fig. 24, Table VI d)
On the line from the Falklands to South Georgia in the middle of February we find
small catches at Sts. 828 and 829 (Fig. 16), in sub-Antarctic water, consisting of stage iil
and no trace of a parent generation.
The disappearance of Rhincalanus gigas from sub-Antarctic water at the end of the
summer has already been commented upon (pp. 299, 311, 312). In the light of what we
have seen of the course of events during the summer two explanations may perhaps be
advanced to account for the difference between the summer and winter conditions on the
sub-Antarctic side of the convergence. There is at present, however, no evidence to prove
which, if either, of the suggested explanations is correct. It might be supposed that the
Rhincalanus population begins the descent to its winter level much earlier north of the
convergence than south of it. This was found to be true to a certain extent by Mackintosh
(1935), who has shown that it was to the north of the convergence in March 1934 that
R. gigas first began to seek its winter level. But this hardly seems sufficient to account
for the great reduction in the catches within the surface 250 m. in sub-Antarctic water
so early as February in the seasons 1931-2 and 1932-3. If, however, this theory is
correct the population sampled at Sts. 828 and 829 in February 1932 was part of a
stock of which the main body lay at a level below 250 m. and was therefore out of range
of the nets. An alternative, and possibly more probable, explanation is that spawning
is very reduced in sub-Antarctic water during the summer, so that when the over-
wintered generation dies out in late January or February there is only a very greatly
diminished summer spawned advancing generation to replace it. The absence of a parent
generation from the stock at Sts. 828 and 829, in which stages ii and 111 predominate might
suggest that this population was not spawned in the water in which it was taken. It is
RHINCALANUS GIGAS 335
STATIONS _ 828 829 830 B3| 834
DATES _1i7-il 1B-il iS-i| 20-1! 23-il
</00
INDIVIDUALS
e)
oo
ome
|
410)
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UPPER NET [IOOm-Om APPROX].
NUMBERS INSIGNIFICANT
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ANTARCTIC
NUMBERS INSIGNIFICANT
iav)
oO
LOWER NET [250m -100 APPROX |
SPAGES_| 23456 1234561 eS34561eS5456! es 4-516
FALKLAND Is. SOUTH GEORGIA
Fig. 24. Percentage of copepodite stages of Rhincalanus gigas in 1-m. nets. Falkland Islands to South
Georgia, mid-February 1932. (See Table VI d.)
8-2
336 DISCOVERY REPORTS
evident, in view of its age, that it was spawned considerably later than the population on
the Antarctic side of the convergence, but perhaps about the same time as that sampled
at St. 825 at the end of January. However, at both these stations (828 and 829) on the
sub-Antarctic side of the convergence the catches are too small to allow conclusions to
be drawn from them; but if this is the correct explanation of the disappearance of the
Rhincalanus population from sub-Antarctic water at the end of the summer, it must be
supposed that the over-wintered stock is carried northward across the convergence by
Antarctic surface water on reaching the upper layers in the early spring. This would
account for the large catches of Rhincalanus in sub-Antarctic water early in the year
but one must suppose that most of the population in this water dies out without
spawning during the summer.
At the two stations (830 and 831) on the Antarctic side of the convergence, we find
that the catches were enormously greater than on the sub-Antarctic side, though some-
what reduced compared with the same locality in November (Figs. 8, 10). ‘Two distinct
stocks are found here also (Fig. 24), one consisting mainly of stages iv, v and vi, at the
warmer station (830, 4:15° C.), and a younger stock consisting of stages ii and iv at
the colder station (831, 2°74°C.). It may be suggested that the stock at St. 830, just on
the Antarctic side of the convergence, was spawned in the eastern Drake Passage in
water with an average temperature higher than 1-0° C. but lower than 4:0° C. (see Fig. 5).
The stock at St. 831 must also have been spawned in the eastern Drake Passage, but
in water with a temperature lower than 1-0° C. (see Fig. 5). Its age indicates that it
was spawned later than the stock in the warmer water near the convergence (St. 830),
so that again spawning has been delayed in the water of lower temperature. It is seen
that the stock in the Bellingshausen Sea current immediately west of South Georgia
in the latter half of February consisted mainly of stages iii and iv (Fig. 24; St. 831),
so that it was not much farther advanced in age than the population sampled in the
same water in the South Atlantic east of South Georgia during the first half of January
(Fig. 21; Sts. 796, 802 and 803). Near the convergence, between the Falklands
and South Georgia (St. 830), the population is older, mainly in stages iv and v, but
still younger than might be expected if it had been spawned at the same time as the
stock east of South Georgia earlier in the season. It is evident then that the spawning
in the eastern Drake Passage, where the population at Sts. 830 and 831 originated,
must have taken place considerably later in the season than the spawning in the
South Georgia area. It occurred earlier in the warmer eastern Drake Passage water,
however, than in the colder water, as may be seen from the difference in the ages of
the populations sampled at the two stations 830 and 831.
SUMMARY, FALKLAND SECTOR, SEASON 1931-2
1. Rhincalanus gigas passes the winter generally in copepodite stages iv and v, as
has been found for species in the northern hemisphere (p. 324).
2. In waters north of the Antarctic convergence (warmer than 4:0° C.), however, it
appears that many individuals may reach stage vi by November. In Antarctic water
RHINCALANUS GIGAS 337
colder than —1-5° C. many individuals do not develop beyond stage iii before the
spring (pp. 324, 326).
3. In the Scotia Sea and around South Georgia the population was found to be
mature (in the adult stage) about the end of the first week in December (p. 326).
4. Nauplii and very young stages were taken at one station in South Atlantic water of
Bellingshausen Sea origin in the middle of December (St. 778, 18. xii. 31). At the end
of the first week in January in this water an advancing summer generation was found in
stage ili (p. 326).
5. In the oldest type of Weddell Sea water (o-1-0° C.), the population was mainly
in stage v—except at Sts. 763, 765, 768 and 779, where it was mainly in the adult stage
(stage vi) (p. 330).
6. In water flowing out of the Weddell Sea having an average temperature for
o-100 m. below o° C. the population consisted almost entirely of adults and was taken
in the upper nets. No young forms were found at all. In water flowing into the
Weddell Sea along the coast of Coats Land south of 66° S the population consisted
mostly of stage iv and was found in the lower nets (p. 332).
7. A population again in stage ii was found at one station (825) in late January in the
Scotia Sea south of South Georgia (p. 334).
8. Between the Falklands and South Georgia in the middle of February two stocks
were found—one in stages iv, v and vi in warmer Antarctic water and another in stages
ii and iv in colder Antarctic water near South Georgia. A much reduced young
population was taken in sub-Antarctic water (p. 336).
g. From the above facts it has been concluded that the spawning of R. gigas took place
during the season 1931-2, in the Falkland Sector, in December and probably throughout
January. It occurred first in Antarctic water from the Bellingshausen Sea in the South
Atlantic, where the temperature was between 1-o and about 4:0° C. Spawning in the
Scotia Sea and eastern Drake Passage took place later, also in water from the Bellings-
hausen Sea. There is evidence that the spawning everywhere took place earlier in
warmer than in colder Antarctic water. The part of the Rhincalanus stock belonging
to the Bellingshausen Sea current which drifted into the “oldest” type of Weddell
Sea water (o-1-0° C.) failed to reach maturity by the middle of January. No spawning
at all apparently took place in Weddell Sea water with a temperature below o° C. at least
before the end of January. The population found in the southern Weddell Sea, in the
middle of January, in water flowing in from the east south of 66° S, was judged to be
the same advancing summer generation as was found in the South Atlantic at the
beginning of the month. The population of the Weddell Sea is thought to result from
an invasion from an outside area and to be carried into the Weddell Sea either in
Atlantic warm deep water, or in the deep current originating in the South Indian Ocean
which flows into the Weddell Sea south of 66° S along the coast of Coats Land. A late
and much reduced spawning appears to have taken place in sub-Antarctic water.
338 : DISCOVERY REPORTS
South Indian Ocean and Australian Sector. Winter months, April, May,
June 1932 (Fig. 25, Table VI e)
Fig. 25 shows the population analysed into stages in the South Indian Ocean in April,
at three stations in the Australian Sector in May and one in June.
The population in April in the Indian Ocean Sector is younger than one would expect
if spawning had taken place in December, as it apparently did in the Falkland Sector.
Stages iii, iv and v are the dominant stages in different proportions. At St. 851 par-
ticularly large numbers of stage iii were taken in the surface haul. In the absence of
further data we must conclude that spawning took place later in this sector of the
Antarctic in the season 1931-2 than it did in the Falkland Sector.
On the line from Enderby Land to Fremantle, where the catches were in the lower
nets, the stock consisted mainly of stage v, with a high proportion of stage iv (35-40 per
cent). At the most northerly station (862) there was a high proportion of stage iii. In the
absence of more complete data it is not possible to do more than note that the population
in the warmer waters of the Antarctic Zone at this time of year seems to have been
younger than the population in the colder water. The explanation of this might perhaps
lie in the different vertical distribution of the various copepodite stages in different
places. It is seen that adults were quite absent from the line from Enderby Land to
Fremantle, although present in large proportions, especially in the lower nets, on that
from Cape Town to Enderby Land. They have presumably sunk below the 250-m.
level on the line to Fremantle. Thus also it may be that more stage v copepodites have
sunk below the 250-m. level at St. 862 than at St. 860 and more again at St. 860 than
at the two more southerly stations.
At St. 887, at the pack-ice edge south of Australia at the end of May, we find that a
spawning had evidently recently taken place. Great numbers of stages i and ii, with
nauplii, were taken in the surface net. This is the only station in the Australian Sector
at which any Rhincalanus were taken in the surface net, and the catch was a com-
paratively large one (533), while the number in the lower haul was insignificant (54).
At St. 891, just south of the convergence on the way to Melbourne, we find the genera-
tion which must have resulted from this spawning in stage 111, and in the lower nets only.
This, then, is the mid-winter spawning of the previous season’s summer generation, and
the population sampled at Sts. 887 and 891 consisted of the young over-wintering genera-
tion which, as we may conclude from what has gone before, will pass the winter mainly
in stages iv and v below 250 m., and reappear at the surface in the spring. There is no
evidence from the data available as to the limits within which the winter spawning took
place, but it seems probable that it occurred throughout the entire range of the Antarctic
waters, since young stages were found at St. 891, near the convergence, as well as at
St. 887 at the edge of the pack-ice. The stock in the warmer Antarctic waters (St. 891)
appears to have spawned earlier than that at St. 887, at the pack-ice edge, having reached
stage ui by the end of May while that at St. 887 was only in stage i. This, however, is
what we might expect from our observations in the Falkland Sector during the
summer.
RHINCALANUS GIGAS 339
STATIONS _ 850 B51 853 856 858 860 862 887 89) S04
DATES —IS-IV I7-IV I9-iV | e2-IV 24-IV 26-IV. 28-IV | 27-V 30-V 20-VI
— hb
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M4 40 ee
a ‘ Lu
ra} faa)
- | =
aw
tu Ze
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STAGES _ 23456 23456 2345623 4562345623456 23456 N!23456 23456 23456
APRILIS32.CAPE TOWN — APRIL 1932. ENDERBY LAND — MAY 1932 JUNE 1332
ENDERBY LAND FREMANTLE |!CE-EDGE —MELBOURNE MEE ANE
Fig. 25. Percentage of copepodite stages of Rhincalanus gigas in 1-m. nets. South Indian Ocean and
Australian Sector. Winter months, April, May, June 1932. (See Table VI e.)
340 DISCOVERY REPORTS
At the station just south of the Antarctic convergence (St. go4) nearly a month
(20. vi) later than the stations above mentioned, on the line southwards from Mel-
bourne, we find the winter generation largely advanced to stage iv, though many stage ili
were still present.
There are certain striking features noticeable in the analyses of the stock in these
winter months. One of these is the complete absence of adults from the catches after
the middle of April. Adults were almost entirely absent from the catches on the line
from Enderby Land to Fremantle at the end of April, when one would suppose that the
summer generation was approaching maturity and was about to spawn. They were
similarly quite absent in May, south of Australia, after spawning had taken place. As
already remarked, a study of the stations taken in April on the Cape Town to Enderby
Land line leads one to believe, though the evidence is admittedly slender, that the adults
descend from the surface towards the winter level earlier than the younger copepodite
stages (cf. upper and lower nets at Sts. 850 and 851, Fig. 25). One must assume that
the adults have sunk beyond the range of these nets by the end of April, while the
younger stages remain still within their range. It is hardly possible therefore to regard
the hauls on these two lines as representative of the populations in these areas. The
second striking feature of the catches during the winter was the swarm of very young
stages near the surface at the end of May at the edge of the pack-ice (St. 887), since
elsewhere at the same time of year small catches were being taken which appeared in the
lower nets only. It seems probable that the explanation of this lies in the peculiar
hydrological conditions existing at St. 887. This station was situated in the divergence
region (Deacon, 1936) exactly upon the boundary between the East and West Wind
Drift currents, where, owing to upwelling and mixing, warm deep water is carried up
to within 60 m. of the surface. It seems certain, from the position of the main mass of
the population at this time of year, at stations other than 887, that the winter spawning
during May took place below the 250-m. level in southward-flowing warm deep water,
out of range of the 250-100 m. net, but that at St. 887, near the edge of the ice, the
young forms were carried upward to within 100 m. of the surface in the upwelling warm
water. This is confirmed by the presence of stage iii in the lower net at St. 891, at almost
the same date, away from the divergence region, and of stages iii and iv in a similar
position about a month later.
SUMMARY, SOUTH INDIAN OCEAN AND AUSTRALIAN SECTOR,
WINTER MONTHS 1932
1. Inthe South Indian Ocean the summer spawning in the season 1931-2 apparently
took place later than in the Falkland Sector.
2. The mid-winter spawning in the Australian Sector in 1932 took place during May
and the beginning of June. The winter generation was found in stage ui at the end of
May and stage iv in the middle of June in northern Antarctic waters.
3. The winter spawning took place in southward-flowing warm deep water, but the
young products were found at one station (887), taken at the edge of the pack-ice,
RHINCALANUS GIGAS 341
carried up towards the surface in upwelling warm deep water in the divergence region
between the East and West Wind Drift currents.
4. Adults were absent from the catches after the end of April and had, after that time,
presumably sunk out of reach of the 250-100 m. net.
Drake Passage, October to mid-November 1932
(Fig. 26, Table VI f)
When Rhincalanus gigas reappeared in the catches in October 1932 on the line of
stations across the western end of the Drake Passage (Sts. 984-95) we find a remarkably
high proportion of adults in the catches. This is particularly noticeable in the lower
hauls at stations north of the convergence. In the upper nets a high proportion of
stages iv and v was present at each of the three stations north of the convergence,
while the catches in the lower nets at these stations were composed almost entirely of
adults. This might perhaps suggest that the younger stages rise to the surface earlier
in the season than the adults. At St. 978, at the beginning of October, we find a high
proportion of stage ii in the upper nets but the catch was too small to give a reliable
estimate of the population. The population generally seems to be in a much more ad-
vanced condition than in November 1931 in this same region. On the other hand at Sts.
1015, 101g and 1021, about a fortnight later at the eastern end of the Drake Passage, the
population consisted of stages v and vi (adults) and was thus in the same condition as at
the end of November 1931 in this area. This must be due to the growth of stage iv into
stage v in the fortnight intervening between these two north to south lines (Sts. 984—
95, 1015 and 101g). On the evidence available it is not possible to speculate much on
the condition of the population at the western end of the Drake Passage in October 1932.
The stages iv and v certainly belong to the winter-spawned generation, and the condition
of the ovaries (p. 318) indicates that the adults do also, since they were all ‘“‘unripe”
or “‘maturing’’. Evidently a higher proportion of the winter-spawned generation had
reached the adult condition by the spring of 1932-3 than was the case in 1931-2.
Comparison of the isotherm maps (Figs. 5 and 6) shows that the 2 and 3° isotherms
occupied a more southerly position in October 1932 than in November 1931. It has
already been remarked that the season 1931-2 was colder and later than 1932-3 in the
South Georgia region, and the same appears to have been true in the Drake Passage also.
This may perhaps account for the comparatively advanced condition of the overwintered
Rhincalanus population in October 1932 as compared with its condition in November
1931. The population, as was found in November 1931, seems to have advanced farther
in development north of the convergence than south of it, but there is no appearance
of stage ili in the coldest water such as occurred at Sts. 735 and 737.
Scotia Sea and South Atlantic Ocean, mid-November to
mid-December 1932 (Fig. 27, Table VI g)
At Sts. 1015, 101g and 1021, in the western Scotia Sea and in sub-Antarctic water
near the Falklands, we find the population in stages v and vi in the same condition as in
D XIII 9
342 DISCOVERY REPORTS
STATIONS 978 984 388 990 392 eis 1000 1015 IQ!
DATES amen 24-X EO ey ak 27-X egex 1-xi VaX\ 9-x\|
60
40
20
LOWER NET [250m - 100m. APPROX]
t
|
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STAGES_! 2345623456 2345623456 23456 2345623456 2345623456
WESTERN DRAKE PASSAGE — MAGELLAN STRAITS TO ICE-EDGE ae eR EASTERN DRAKE PASSAGE
Fig. 26. Percentage of copepodite stages of Rhincalanus gigas in 1-m. nets. Drake Passage, October to
mid-November 1932. (See Table VI /.)
RHINCALANUS GIGAS 343
November 1931 in this region; but from the middle of November (St. 1031) to the end
of December (St. 1085) we find everywhere a mature stock consisting entirely of adults,
with a few stage v—usually less than 20 per cent.
Some of the stations, for which the stock curves are shown in Fig. 27, were
taken in Weddell Sea water (Sts. 1029, 1031, 1033, 1048, 1050, 1052, 1073, 1076 and
1085, Fig. 2a). The remainder, except 1021 in South Atlantic water near the
Falklands, were taken in the Bellingshausen Sea current (1054, 1056, 1063, 1066 and
1083, Fig. 2a). Sts. 1029, 1052, 1073, 1076 and 1085 were taken in the “‘ oldest” type of
Weddell Sea water (average of o-100 m. between 0 and 1:o0° C.).
At Sts. 1029, 1052 and 1085, in the ‘oldest’? Weddell Sea water, we find a high
proportion of stage v in the upper nets, and, while the lower haul at St. 1029 was not
analysed into stages, the lower hauls at Sts. 1052 and 1085 consisted of adults with
some stage v, less than 25 per cent. At St. 1052, and to a lesser extent 1076, the
proportion of adult males in the lower nets was high, and at these stations it is probably
correct to assume that the population was a mixture of the populations of the Bellings-
hausen Sea current and the Weddell Sea current. St. 1073 was a shallow inshore station
at which only a surface haul was made. It is apparent, however, that in this season,
as in the previous one, the stock in the ‘oldest’? Weddell Sea water is not yet
mature, while it has reached maturity at stations in the Bellingshausen Sea current
proper. This is shown by the high proportion of stage v in the population at Sts. 1029,
1052 and 1085. One must again assume that something has occurred to prevent that
part of the stock originating in the Bellingshausen Sea current from attaining maturity,
and that the action of water colder than 1:0° C. has possibly been to retard the develop-
ment of the stages.
Sts. 1031, 1033, 1041, 1045, 1048 and 1050 were taken in Weddell Sea water of which
the average temperature was less than 0° C., that is water carrying unmelted or melting
pack-ice or water in which ice had recently melted. The population at St. 1033 is per-
haps again a mixture of the Bellingshausen Sea and Weddell Sea stock, and here the
proportion of adult males in the lower nets is rather high (13-8 per cent). At the other
stations the stock is probably purely of Weddell Sea origin. At Sts. rog1 and 1045
the catches of Rhincalanus were too small for satisfactory analysis into stages and the
copepod fauna at these stations was made up of species other than R. gigas, mainly
Calanus acutus and C. propinquus. Sts. 1031, 1048 and ro50, however, show a mature
population which consisted of adults and a few stage v, as was found in this type of
water in the previous season (January 1932). This, if our conclusions drawn from the
stock curves of the previous season are correct, is a population which has failed to spawn
and which originated outside the Weddell Sea, possibly from the previous winter’s
spawning. It was carried into the Weddell Sea in the warm deep water of the East Wind
Drift current, and has risen from the deep water into the surface water during its passage
through the Weddell Sea in the north-easterly current.
With regard to the appearance of males during this season, we have already seen that
the proportion of adult males was high at Sts. 1052 and 1076 in the “oldest” type
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RHINCALANUS GIGAS 345
of Weddell Sea water, where the stock is probably of mixed origin. It was also high
at stations in the Bellingshausen Sea current proper from the middle of November to the
end of December (Sts. 1021, 1054, 1063, 1066, 1083, see Table V 6). A high proportion
of adult males was thus found in the catches from the middle of November to the end of
December in the season 1932-3, instead of from the middle of December to the end of
that month as in the season 1931~2 (see p. 320, Table V a and Fig. 18). Since there were
no observations for January 1933 it is not possible to decide exactly when the catches
ceased to contain a high percentage of adult males during that season.
Thus, in the season 1932-3, we find the stock of Rhincalanus reaching maturity from
the end of November and throughout December in the Bellingshausen Sea current, and
adult males appearing in the catches at the same time. Adult males therefore appeared
slightly earlier than in the previous season and the population became mature slightly
earlier also. In 1931-2 the first station at which a mature stock was found was St. 763
(8. xii. 31), which was in Weddell Sea water, while at Sts. 774 and 775 (16. xii. 31) in the
Bellingshausen Sea current itself there was still a high proportion of stage v in the
catches. In 1932-3 the first station at which a mature stock was found was St. 1031
(20. xi. 32) in Weddell Sea water and the first in the Bellingshausen Sea current was
St. 1054 (3. xii. 32). It may therefore be assumed that, since maturity was reached at
least a fortnight earlier and adult males made their appearance a month earlier, so also
spawning probably began earlier in this season than in the preceding one. Throughout
December, however, there was no appearance of nauplii or young stages such as would
indicate the hatching of eggs. At Sts. 1054 and 1056, north of South Georgia (3. xii
and 4. xii) there was a very small percentage of stage ili—5 per cent and less—but these
hardly indicate that hatching had taken place recently or on an appreciable scale. It is
possible that spawning never took place around South Georgia during the month
of December on a scale large enough to produce a catch of nauplii in the 1-m. net.
During January 1933 the ‘Discovery II’ was engaged in making a running survey of
the South Orkney Islands. During that month no plankton stations were taken, so that
observations for the month of January 1933 are unfortunately lacking. At the end of
that month and during the first week in February a number of plankton stations were
taken in the Bransfield Straits (Sts. 1097-1110; Fig. 26). R. gigas was almost com-
pletely absent from this area, as was found at the end of October and the beginning of
November. The next stations, therefore, at which samples of Rhincalanus large enough
to be analysed were taken, are those worked in the Drake Passage at the end of the first
week in February.
Drake Passage, early February 1933 (Fig. 28, Table VI h)
At the most southerly station (1115) in the Drake Passage there was a small catch
in the lower nets only. The stock curve shows that it consisted of stages iv, v and vi.
At St. 1116, the station to the north, the stock consisted of stages iv and v, without
the high percentage of adults found at St. 1115. The latter station (1115) was situated
just off the Antarctic continental shelf, in a position, again, where warm deep water wells
346 ; DISCOVERY REPORTS
upwards from beneath the Antarctic surface layer. One may therefore expect that the
stock of Rhincalanus taken in the lower nets at this station has been carried into this
position in warm deep water from somewhere farther north. The stock at this station
(1115) is, therefore, probably much the same as that at St. 1116, and it may be possible to
explain the comparatively high percentage of adults at St. 1115 on the assumption that
the autumn descent from the surface has already begun in this area (as it apparently
has—see Fig. 12), and that, if adults sink into the warm deep water before the
younger stages, as we have elsewhere supposed that they do (p. 340), a high proportion
of adults may be expected in this water where it is found moving upwards as at St. 1115.
At Sts. 1116 and 1117 we see what is evidently the summer generation in an advanced
state of development. At St. 1116 the population consisted of stages iv and v, with a
small proportion of adults, and at St. 1117, farther north near the convergence, the
population is considerably older and consisted of stages v and vi (adults). The spawning
therefore which gave rise to the stock at St. 1117, in the warmer waters of the Drake
Passage, must have taken place earlier in the year than that which gave rise to the stock
at St. 1116, in the colder water. No deep hydrological observations were made at St.
1116, so that it is not possible to say with certainty whether it lies within the optimum
range (an average of 1-0-4:0° C. for the o-100-m. layer) of spawning or outside it. The
surface temperature was 2°76° C., so that it seems probable that this station lay
within these limits. It must be remembered, however, that the population sampled
at this station in early February had drifted from considerably colder water farther to
the south-west where the average temperature (Fig. 7) may have been lower than 1-0° C.
At St. 1117 the average temperature was 4:11° C., but the population sampled at this
station must again have drifted from the south-west where the temperature of the water
was colder than this, though probably not colder than 1-0° C. (Fig. 7). The age of the
stock at both these stations seems to point to an early spawning in these waters. In the
season 1931-2 it was seen that spawning took place first in December east of South
Georgia and later in the Scotia Sea and Drake Passage. In the season 1932-3 it has been
suggested, from the time of appearance of a high proportion of males and of the attain-
ment of maturity by the over-wintered generation, that spawning may have taken place
earlier than in the previous season. The condition of the population at Sts. 1116 and
1117 in the Drake Passage in early February 1933 seems to confirm this suggestion,
although it is evident from the stock curves at St. 1083 (stages v and vi; Fig. 27), south
of South Georgia, that no spawning took place in the colder waters of the Scotia Sea
before the end of December. As will be seen in the following section (p. 348) conditions
at Sts. 1127 and 1131 also point to a later spawning in the Scotia Sea, as compared
with the warmer waters farther west near the convergence.
Falkland Islands to South Georgia, February 1933 (Fig. 28, Table VI h)
The Rhincalanus population was analysed at five of the stations taken between the
Falkland Islands and South Georgia in late February 1933.
On the Antarctic side of the convergence stages iii and iv predominated at the two
RHINCALANUS GIGAS 347
STATIONS = IIIS. HIG 7 He2 1123 1125 127 13!
DATES 6-li 7-il 7-iI 2o-i| e2o-ii 2i-il 23-ii 24-ii
ioe)
Ox
\
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2 |
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= =
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5 Za
T SSaleorlaalel
STAGES | 23456 2345623456 23455 2345 6es4 ob 2s 4a leS4sib
DRAKE PASSAGE SOUTH ATLANTIC
Fig. 28. Percentage of copepodite stages of Rhincalanus gigas in 1-m. nets. Drake Passage and South
Atlantic Ocean, February 1933. (See Table VI /.)
348 DISCOVERY REPORTS
stations near South Georgia (Sts. 1127 and 1131). At St. 1125, farther west near the
convergence, the population was in stages iv, v and vi, together with some stage 111.
At this station the adult females (see p. 318) were mostly unripe or maturing,
and this population had evidently been spawned during the current summer. The
average temperature at St. 1125 was 3:19° C., and the population in that area must have
drifted from some position in the eastern Drake Passage or western Scotia Sea to the
south-west. The spawning which, earlier in the summer, gave rise to the stock at this
station must, therefore, have taken place in water having an average temperature
probably lower than 3-0° C. but higher than 1-o° C. (Fig. 7). The population sampled at
Sts. 1127 and 1131, however, consisting predominantly of stages i1i and iv, must, from
its age, have been spawned later than that at St. 1125. It probably originated in the
western Scotia Sea in water having an average temperature considerably nearer the lower
limit of the optimum spawning range (1-0° C.) than that in which the population at
St. 1125 originated. Thus, again, spawning took place later in the colder water.
The stock sampled at St. 1125 (stages iv, v and vi) would appear to have been
spawned at about the same time as that which was sampled at Sts. 1116 and 1117 in
the Drake Passage (stages iv and v and v and vi respectively). The stock at Sts. 1127
and 1131, however (stages iii andiv), must have been spawned much later in the
season, so that a southward, and possibly eastward, movement of the spawning area
is discernible in the season 1932-3, as in the previous season, from the warmer to the
colder Antarctic surface water of the Drake Passage and Scotia Sea.
The population at St. 1125 was older than that which was sampled at St. 830 in
the same position in the preceding February (cf. Figs. 24 and 28) since it contained
a higher proportion of adults and stage v and, taking both nets together, a smaller
proportion of stage iii. ‘This again confirms the suggestion that the spawning occurred
earlier in the Bellingshausen Sea current in 1932-3 than in 1931-2. The stock at 1127
and 1131, on the other hand, farther east near South Georgia, is of the same age as
that found in this region in February 1932 (St. 831; Fig. 24) so that these two popu-
lations, sampled in the South Georgia region at the same time in two succeeding
seasons, may be judged to have resulted from spawnings which took place in the
Scotia Sea at the same time of year in both seasons. In 1931-2 it was seen that the
spawning east of South Georgia in the South Atlantic took place a good deal earlier
than that which gave rise to the population at 831. Thus in both seasons the spawning
seems to have moved southwards into the Scotia Sea from the South Atlantic and the
Drake Passage; but while the spawning in the Drake Passage, and probably in the
South Atlantic, took place earlier in 1932-3 than in 1931-2, it seems to have occurred
at approximately the same time of year in both seasons in the Scotia Sea.
On the sub-Antarctic side of the Antarctic convergence, between the Falklands and
South Georgia in February 1933, the two hauls large enough to be analysed, at Sts. 1122
and 1123, showed a population in stages iii, iv and v. The state of affairs at these two
stations was possibly the same as that at Sts. 828 and 829 in the previous season, and the
population sampled here may have been, perhaps, the product of a much reduced late
RHINCALANUS GIGAS 349
spawning, in sub-Antarctic water. The age of the stock suggests that it had resulted
from a considerably later spawning than that which gave rise to the stock on the
Antarctic side of the convergence (St. 1125).
Weddell Sea, March 1933 (Fig. 29, Table VI 7)
During March a line of stations was taken from South Georgia to the pack-ice edge in
69° 22’ S and 9° 27°5’ E. The Rhincalanus population was analysed at six of these sta-
tions. Three of the stations, at which the catches were analysed into stages, were in water
flowing north-eastwards out of the Weddell Sea towards the South Sandwich Islands as
the Weddell Sea current (Sts. 1138, 1142 and 1144), and three were taken in the East
Wind Drift current flowing westwards into the Weddell Sea along the coast of Coats
Land (Sts. 1148, 1150 and 1152).
At the first group of stations, those in water flowing out of the Weddell Sea, the stock
consisted mostly of stages iii and iv. St. 1138 was situated near the boundary between
Weddell Sea water and water of Bellingshausen Sea origin. The average temperature
was 0°76° C. (‘“‘oldest’’ Weddell Sea water), and it is therefore probable that the stock
at this station contained a mixture of the populations of the Bellingshausen Sea current
and of the Weddell Sea current. We saw that at St. 1131, a little over a week earlier near
South Georgia, the population also consisted of stages 111 and iv, so that the probability
is that the same population was sampled at both these stations. At St. 1142, where the
catch occurred only in the lower net, the stock consisted almost entirely of stage iv. The
temperatures of the surface 200 m. at this station show that it was worked in a tongue of
warm water moving south from the north (Deacon, 1936), so that the stock found in the
lower nets probably originated in the South Atlantic. It is very similar in its constitution
to that at Sts. 1138 and 1131, and it thus seems extremely probable that the populations
sampled at Sts. 1138 and 1142 are similar in origin and are carried into the Weddell Sea
by warm deep water from the South Atlantic. At St. 1144 there is a northerly move-
ment at the surface and a southerly movement from the Atlantic in the lower levels,
which is strongest at about 400 m. (Deacon, 1936). This southerly movement, however,
is less perceptible at St. 1144 than at St. 1142. The catches of Rhincalanus at St. 1144
were small, but it will be seen from Fig. 29 that the stock in the upper net, in water with
a northward tendency, was younger (stages iii and iv) than that in the lower net (mainly
stage v) which may be expected to have a mixed origin, part of the stock, at least, having
been carried southward in the lower layers. It will be noticed that the population
sampled by the lower net was similar in constitution to that found at the following
stations (Sts. 1148, 1150 and 1152) in the East Wind Drift current. The catch taken by
the upper net was too small for any definite conclusion to be drawn, but its age was
the same as that of the population sampled at the preceding stations (1138 and 1142).
It may be that it belongs to the same stock but, alternatively, it might perhaps suggest
that a spawning had taken place in Weddell Sea water very much later in the year than
in the Bellingshausen Sea current. On this point, however, the evidence is at present
insufficient.
D XIII fo)
350 DISCOVERY REPORTS
STATIONS = 1138 1142 1144 1148 1150 152 16)
DATES 2-ill 4-ili S-ili 3 -lii 10-Iil 1O-1i | I9-II
h
BO
60
40
NONE
20
UPPER NET [100m- Om APPROX]
N
Tigi aoal ral
SVAGES_I 23455 23456 2aa shes 56 2ZIg55 23456 234 SE
fe)
Pare lh
=<
eS ao
a
ae
< =
: js
&
= be =
| Zz
= o
oO ep)
A 2
ot 40
jam
oF lu
2 2
G20
Fa
te
je)
=J
Fig. 29. Percentage of copepodite stages of Rhincalanus gigas in 1-m. nets. Weddell Sea, March 1933.
(See Table VI 7.)
RHINCALANUS GIGAS 351
At Sts. 1148, 1150 and 1152, in the East Wind Drift current, we find a population,
spawned in South Atlantic water to the east, probably in the middle of summer. This is
a population which corresponds with that found in January 1932 at Sts. 816 and 817 in
stage iv (p. 332). The fact that in March 1933, farther east, it was found only as far
advanced as stage v points to a somewhat later spawning of this stock than was
indicated in the previous season.
The 1-m. net was used at one station on the line from the ice edge to South Africa at
the end of March 1933. This station (1161) was taken just south of the convergence be-
tween the pack-ice edge in the Weddell Sea and South Africa. A summer generation
was found here in stage v, with adults in the lower net. The majority of the catch was in
the lower net.
SUMMARY, FALKLAND SECTOR, SEASON 1932-3
1. The over-wintered stock appeared within the range of the nets at the end of
October 1932 in stages iv, v and vi. Stage vi (adults) were particularly abundant north
of the convergence (p. 341).
2. In the eastern Drake Passage and western Scotia Sea the population in November
was in stages v and vi. From the end of November until the end of December the
stock was everywhere mature in water of Bellingshausen Sea origin (p. 345).
3. Inthe “oldest” water of Weddell Sea origin at the end of November and beginning
of December the population was in stage v, while at stations in Weddell Sea water with
an average temperature below o° C. the stock consisted of adults with no young stages.
The population in the ‘oldest’? Weddell Sea water (o-1-0° C.) is presumed to have a
mixed origin and to belong partly to the Weddell Sea current and partly to the Bellings-
hausen Sea current. Thus, as in the previous season, the part of the population which
belonged to the Bellingshausen Sea current had apparently failed to reach maturity at
the same time as the stock in the Bellingshausen Sea itself (p. 343).
4. Spawning in the South Georgia region is thought to have taken place earlier in
the season 1932-3 than in 1931-2, in view of the earlier attainment of maturity by the
population and the earlier appearance of adult males. Spawning was not apparent from
the catches, however, during December, and there were no observations for January
(p. 345):
5. Inthe Drake Passage in February a summer generation in stages iv and v was found
in the colder waters. In the warmer waters there was an older summer stock in stages v
and vi. It was concluded from this that spawning had taken place earlier in the warmer
Antarctic waters near the convergence than in the colder Antarctic waters farther south.
(p. 346).
6. Between the Falklands and South Georgia in the second half of February two dif-
ferent stocks were again found in Antarctic waters—a younger one in stages i11 and iv in
the colder water near South Georgia and an older one in stages iv, v and vi in warmer
water farther west near the convergence (p. 348).
7. In the Weddell Sea in March, again, two different stocks were found. In water
10-2
352 DISCOVERY REPORTS
flowing out of the Weddell Sea there was a population in stages ii and 1v, and in water
flowing into the Weddell Sea as the East Wind Drift current, south of 66° S, there was
a population in stage v. One station (1142) was taken in a tongue of water flowing south-
wards from the South Atlantic. Here the Rhincalanus population was in stage iv. It is
presumed that the stock at this station and at those on this line taken in water flowing
out of the Weddell Sea owes its origin to the South Atlantic deep water (p. 349).
8. It would appear that in the season 1932-3 spawning began in the warmer Antarctic
water near the convergence perhaps at the beginning of December near South Georgia,
but possibly earlier than this farther west in the Drake Passage, and later spread south-
wards into the Scotia Sea. It is thus possible to state that there must be a movement
southwards of the spawning area from the convergence into colder Antarctic water as
the summer advances (pp. 345-8).
COMPARISON OF SEASONS 1931-2 AND 1932-3, FALKLAND SECTOR
In the first half of both seasons, 1931-2 and 1932-3, the area of maximum abundance
of Rhincalanus gigas lay in the Drake Passage, Western Scotia Sea and South Atlantic,
and the area of greatest scarcity in the Weddell Sea and in water of Weddell Sea origin.
In the first half of 1931-2 the region of greatest abundance, in which more than 10,000
individuals were taken at all stations, occupied Antarctic water of Bellingshausen Sea
origin over a wide area in the Falkland Sector from the western Drake Passage to the
South Atlantic. In the early part of the second season, 1932-3, however, this region was
restricted to a comparatively small area between South Georgia and the Falkland
Islands. This was perhaps in part due to the fact that the waters of the Drake Passage
were investigated nearly a month earlier than in the previous season, so that the main
mass of the population was still out of range of the nets. Between the Falklands and
South Georgia in February much the same conditions were found in both seasons. ‘The
catches were fairly large on the Antarctic side of the convergence but smaller than they
were in this area earlier in the year, in November and December. On the sub-Antarctic
side of the convergence a very marked reduction in the catches was found during
February in both seasons. This may either be due to the fact that the winter descent
from the surface strata takes place earlier north of the convergence in sub-Antarctic
water than south of it in Antarctic water, or, more probably, to the reduction of the
summer spawning in the sub-Antarctic so that the over-wintered generation in those
waters dies out after mid-summer and is replaced by a greatly diminished summer
generation.
In 1931-2, in the Bellingshausen Sea current, the ascent from the winter level to the
surface apparently took place more irregularly and over a longer period than in 1932-3.
During the latter season the majority of the catches appeared in the upper nets from the
beginning of November onwards until February. In 1931-2, however, the figures sug-
gest that the ascent to the surface began near the convergence in November, but that at
stations away from the convergence it did not appear to have taken place until the
middle of December. In water of Weddell Sea origin in both seasons the catches were
RHINCALANUS GIGAS 353
usually in the upper nets in all but the “oldest” type of water (o—-1-0° C.). No observa-
tions were made in the South Atlantic water east of the South Sandwich Islands during
the second season comparable with those taken in January 1932.
In 1931-2 the population in waters of Bellingshausen Sea origin around South Georgia
and in the Scotia Sea came to maturity in the middle of December, and males appeared
in the lower hauls in increased numbers at the same time of year. Nauplti were taken at
one station in the South Atlantic, in Antarctic surface water of Bellingshausen Sea origin,
on the eighteenth of December. At the end of the first week in January, in the same
water, an advancing summer generation was found in stage ili. Spawning evidently began
in the middle of December and possibly continued throughout that month in Antarctic
surface water of the South Atlantic east of South Georgia. Spawning and hatching
of the eggs apparently took place within a very short time. In 1932-3, however, the
population in the Scotia Sea and around South Georgia was found to be mature at the
end of November, and males began to increase in the catches at the same time. The
maximum number of males appeared at the beginning of December during this season,
as against the middle of that month in 1931-2. It is, therefore, justifiable to suppose
that spawning began correspondingly earlier—a fortnight or three weeks—in 1932-3
than in 1931-2 in the waters around South Georgia. The condition of the summer
generation in the Drake Passage in early February (stages iv, v and vi) confirms this
supposition.
Comparison of the isotherm charts for the seasons 1931-2 and 1932-3 (Figs. 5, 6)
shows that the former was a colder and ‘‘later’’ season than the latter. In the spring
of 1932-3 the isotherms for 1-0° C. and over occupied a more southerly mean position
than in the spring of 1931-2. This is less true of the isotherms for o° C. and tempera-
tures below 0°. Warm water, therefore, extended farther south at the beginning of
1932-3 than at the beginning of 1931-2 and the transition from warm to cold water
from lower to higher latitudes was correspondingly more abrupt. The pack ice also
was farther north in 1931-2 than in 1932-3. In the Drake Passage at the end of
November 1931 the pack ice was met with in about 64° S. (St. 735) and was followed
through the Drake Passage to about 60° S. (St. 741) where it trended away southwards.
It thus lay far to the north of the South Shetlands. It was met with again near the
South Orkneys at the beginning of December and was again followed north-eastward
to about 57° S. (St. 767) in the longitude of South Georgia. At the end of October 1932,
however, the pack ice was met with in 67° S. in the western Drake Passage (St. 995)
and the Bransfield Straits were entirely free during early November. At the end of
that month the ice was followed from about 62° S. in the longitude of the South
Orkneys (St. 1035) north-eastwards to about 58° 30’ S. (St. 1045, between Bristol and
Montague Islands) in the South Sandwich group. ‘Thus appearances strongly suggest
that the difference in the spawning time of R. gigas in the two seasons may be con-
nected with these differences of temperature and ice conditions.
In 1931~2 no spawning at all took place in Weddell Sea water, at least before the end
of January; but the line taken from South Georgia through the waters of the Weddell
354 : DISCOVERY REPORTS
Sea in March 1933 might perhaps suggest that some degree of spawning may take place
in the warmer water of Weddell Sea origin much later in the season than the main
spawning in waters of Bellingshausen Sea origin. The station in question here, how-
ever, certainly does not provide sufficient evidence for a statement on this point.
In both seasons, between the Falklands and South Georgia, a similar state of affairs
was found—a maturing summer generation in warm Antarctic water near the con-
vergence and a younger generation in colder water near South Georgia. Similarly in the
Drake Passage in February 1933 the summer generation was found to be much older in
warmer Antarctic water than in colder water farther south. Appearances suggest that
in both seasons spawning took place later in the colder than in the warmer Antarctic
water. In 1931-2 it took place later in the Scotia Sea, south-west of South Georgia
(St. 825), than in South Atlantic water east of the island, and further the stock
spawned in the Scotia Sea was found in February of both seasons, between the Falklands
and South Georgia, to be of the same age, so that the presumption is that spawning
occurred at roughly the same time in the Scotia Sea in both years. In the season 1931-2
spawning began in early December in the South Atlantic, in water of Bellingshausen
Sea origin, east of South Georgia and spread later into the Scotia Sea. In 1932-3 there
is also evidence that spawning took place first in the warmer Antarctic water and later
spread into the colder waters of the Scotia Sea, and in the Drake Passage in this season
there is evidence of a similar movement of the spawning southwards from warmer into
colder water. There is thus discernible in both seasons a trend of the spawning south-
ward as the summer advances.
DISCUSSION
The conditions revealed by the stock curves for the latter half of the seasons 1931-2
and 1932-3 do not admit of any straightforward explanation. We saw that in the Ant-
arctic water flowing northwards from the Drake Passage and Bellingshausen Sea the
Rhincalanus population came to maturity in late November or in December around South
Georgia. Adult males appeared in the lower nets at that time, and one may assume
that the main spawning occurred then. It is evident, however, that during both seasons
a number of different populations was sampled having different ages in different regions,
even when allowance has been made for patching and swarming and for the inaccuracies
of the type of net employed.
In the season 1931-2, at least three age groups were found east of South Georgia in
January. In Bellingshausen Sea water, in the South Atlantic Ocean, there was an
advancing summer generation. In Weddell Sea water of a certain temperature (between
o and 1-o° C.) there was a population mainly in copepodite stage v, which was presumed
to have been carried southward in the Atlantic warm deep water, and in Weddell Sea
water with a temperature below o° C. there was a population consisting almost entirely
of adults. At the end of January 1932 a station (825) near the boundary between
Weddell Sea and Bellingshausen Sea water near South Georgia showed a population
RHINCALANUS GIGAS 355
of the same age as the advancing summer generation sampled three weeks earlier in
the South Atlantic.
In the southern Drake Passage in early February 1933 a half-grown summer genera-
tion was found, while in the more northerly Antarctic water in the Drake Passage,
near the convergence, there was a still older summer generation. Between the Falklands
and South Georgia in February the conditions were remarkably similar in the two
seasons (1931-2 and 1932-3). In both seasons in Antarctic water near the convergence
(Sts. 830 and 1125) a summer generation was found approaching maturity, while near
South Georgia, in colder water, the summer generation was found to be much younger
(Sts. 831, 1127 and 1131).
In Weddell Sea water in March 1933 two apparent age groups were found—a half-
grown summer generation in water flowing out of the Weddell Sea in a north-easterly
direction and a slightly older generation in water flowing into the Weddell Sea in a
westerly direction south of 66° S.
Again in the Australian Sector during the winter great numbers of nauplii and very
young stages were taken near the ice, while at the same time of year a very much older
winter-spawned generation was found at the northern Antarctic stations between
Australia and the ice edge. When the over-wintered generation reappeared at the surface
in the spring of 1932-3 in the Drake Passage it was found to be in a more advanced con-
dition than the over-wintered generation which was found a month later in the same
region the year before, when the temperature of the water was lower. In November
1931 there was a pronounced difference between the age of the overwintered generation
in warm Antarctic water and its age in the cold water near the ice edge.
In order to explain the large number of apparently different age groups in different
localities in the Falkland Sector and elsewhere, we have suggested, tentatively, that the
main spawning takes place within a certain sea-temperature range. This range appears
to lie between the temperatures 1-o and 4:0° C. Temperatures below this range have
everywhere a similar effect upon the Rhincalanus population—growth and development
are retarded and spawning is thus delayed. Outside certain wider temperature limits
the spawning is stopped altogether. It is not possible to decide at present where these
wider limits lie, but appearances in the Weddell Sea suggest that the lower limit might
be between o and — 1:0° C. The effect of temperatures higher than 4-0° C. also seems
to be to inhibit spawning, since very little spawning appears to take place in sub-
Antarctic water.
The dependence of the breeding of marine animals upon constant optimum tem-
perature limits has been demonstrated and discussed by Orton (1920) and Runnstrém
(1927). Orton wrote (p. 362): “‘’ Temperature limits seem to influence breeding in various
ways which appear to be dependent upon the limitation of the breeding period by
apparently constant maximum and/or minimum temperatures. These temperatures
appear to be physiological constants for the species.” Runnstrém showed that these
relationships between breeding and temperature have a direct bearing on the geo-
graphical distribution of the species.
356 . DISCOVERY REPORTS
Now in the Falkland Sector of the Antarctic, as already seen (p. 292), there was, in
the season 1932-3, a southward movement of the isotherms towards the end of the
summer. This was more marked for the lower temperatures below the 3-0° C. isotherm
than for higher temperatures, and it was especially pronounced in the Weddell Sea area,
south and south-east of South Georgia (Figs. 6, 7). This, in all probability, is due to
the break-up of the pack-ice as the season advances. The region of optimum temperature
(1-0-4:0° C.) for the spawning of Rhincalanus thus extends itself southwards towards
the end of the summer, and there is every reason to believe that this is a phenomenon
of yearly occurrence, accompanied by the replacement of a “cold-water” plankton by
a ‘‘warm-water’’ one in higher latitudes towards the end of the season (Mackintosh,
1934). This would then provide an explanation of the late summer spawning of
Rhincalanus in the higher latitudes and of the general southward movement of the
spawning area, for the stock in water which is below the optimum temperature limit
will not spawn until either it has drifted into warmer water within the spawning range
or the water itself has been raised to within the limits by the seasonal increase in
temperature, consequent upon the southward movement of the isotherms. In this
manner, therefore, the spawning time may be related to the break-up of the pack-ice.
The correlation between the time of spawning of R. gigas and the position of the
pack-ice, as already mentioned, further suggests that ice conditions, through their
influence upon the temperature of Antarctic seas, are the governing factor in deter-
mining the spawning of this species.
We have suggested, in connection with the delay of the spawning time of Rhincalanus
in colder waters, that the relationship of the temperature to growth, that is to develop-
ment, is a factor of the greatest importance, and that in colder waters the spawning time
is delayed by the retardation of the attainment of maturity in the parent generation.
We have seen that in Weddell Sea water having an average temperature for 0-100 m.
between o and 1-0° C. the Rhincalanus population in January 1932 had only reached
copepodite stage v in development (p. 330), while at stations in South Atlantic water
where the temperature of the surface 100 m. was above 1:0° C. the population had
spawned and hatched eggs. Thus over-wintered forms which drift into Weddell Sea
water having a temperature below 1:-o° C. fail to reach the adult stage by midsummer.
1 Since this report went to press a paper by Ottestad (1936) has appeared dealing with the biology of
four species of Antarctic copepod (Calanus acutus, C. propinquus, Rhincalanus gigas and Metridia gerlachet)
from the collections of the Norvegia Expedition. The author found a relationship between the com-
position of the stock in stages and the temperature of the surface layers in C. acutus, C. propinquus and,
to a lesser extent, MM. gerlachei. He related the spawning of these species to the break up of the
pack-ice, and concluded that as the older individuals drift northwards into water uncovered by pack-ice
they “mature and commence to spawn” (p. 23). He found no such relationship, however, in R. gigas
and concluded that “there must be a fundamental difference in the life histories of the two species”
(C. acutus and R. gigas, p. 28), and that R. gigas, must be a native of sub-Antarctic waters. The
conclusions of Ottestad for C. acutus and C. propinquus are similar to those which we have reached,
independently and with more abundant material, for R. gigas. The two former species evidently
spawn when the temperature of the water in which they are carried reaches a certain optimum, which lies
within lower limits for these species than for R. gigas.
RHINCALANUS GIGAS 357
We also noted that in November 1931 in the Drake Passage (p. 324) the over-wintered
population in warm sub-Antarctic water consisted mostly of adults, while that in
Antarctic water, south of the convergence, consisted mostly of stages iv and v. In the
coldest Antarctic water (— 1-5° C.) comparatively large numbers of stage iii were taken.
Evidently, young stages which developed during the winter in the coldest Antarctic
water only reached stages iii and iv by the spring, while those which developed in warmer
Antarctic water reached stages iv and v. 'The same age difference, although less marked,
was also found in October 1932 in the Drake Passage (p. 341). All the above facts can be
explained on the assumption that, as there is an optimum temperature range for spawn-
ing, so also there is an optimum temperature range for growth and development, and
that temperatures which approach the lower limit of that range slow up the develop-
ment. The limits of this range cannot be exactly fixed in the present work, but they do
not seem to be widely different from those of the optimum spawning range, and it would
appear that an appreciable slowing up of the rate of development of the population is to
be found in water with an average temperature for the o~-100-m. layer below 1:-o° C.
That reduction of temperature does have a retarding effect upon the development of
some marine animals is well known. Murray and Hort (1912, p. 555) quote the lobster,
whose eggs and larvae are only developed during the warmest part of the year, “and
it has been found that a fall of a few degrees is sufficient to retard the development for
several weeks”. Gran (1902) explained the different ages of the stocks of Calanus
finmarchicus in the Norwegian Seas (p. 62) by assuming that “the yearly developmental
cycle is disarranged through the influence of outside factors, especially temperature ”’,
and, again, that ‘“‘the length of life will differ in different regions. External factors can
act upon the rate of development and thus on the length of life” (p. 64).
In this connection it is perhaps permissible to mention the results of Coker (1933),
who experimented with two species of Cyclops. One of these, when kept at room tem-
perature, spent a disproportionately long time in a state of arrested development at
stage iv. It could be made to develop normally, without any arrested stage iv, by being
placed in a refrigerator. Moreover, eggs hatched at room temperature mostly failed to
develop, and those which did so developed slowly and remained at stage iv for 120-140
days, a period corresponding to the theoretical duration of several cycles of develop-
ment. Another species, on the other hand, developed exactly seven times more rapidly
at room temperature than in the refrigerator. Thus while one species passed through its
development normally at a low temperature (about 8° C.) a higher temperature (about
22° C.) slowed down development. The other species behaved in an exactly opposite
way and developed normally at the higher temperatures but was retarded at the
lower. Runnstrém (1929) determined the optimum range for the development of
littoral Mediterranean-boreal forms, but his tabulated results show in every case that
temperatures as little as half a degree above or below the optimum range for the species
had the effect not of retarding development but of preventing it altogether. The eggs
failed to segment, or segmented irregularly and died, or reached early embryonic
stages and then died.
D XIII II
358 DISCOVERY REPORTS
At present we can do no more than suggest that delayed spawning may be due to the
failure of the parent generation to reach maturity by the normal spawning time, owing
to external conditions such as temperature unfavourable to growth.
GENERAL SUMMARY
1. The foregoing paper is an account of the horizontal, and as far as possible the
vertical, distribution of the species Rhincalanus gigas (Brady) in the Falkland Sector of
the Antarctic during the summer seasons 1931-2 and 1932-3, and during the winter
months of the year 1932 around the Antarctic Continent. Some account of the life
history of the species, as far as it can be judged from the data available, has also been
given. The material upon which the paper is based consists of the catches from a large
number of hauls made with the 1-m. stramin net in the Falkland Sector of the Antarctic
and around the Antarctic Continent during the 1931-3 commission of the R.R.S.
“Discovery II’. At every station from which the catches were analysed in this work the
I-m. net was towed from 250 to 100 m. approximately and from approximately 100 m.
to the surface.
2. Rhincalanus gigas is the dominant species in the copepod macroplankton, and thus
in the macroplankton generally, throughout a wide area of the Falkland Sector of the
Antarctic. In the season 1931-2 it constituted over 75 per cent of the copepod catches
in Antarctic water flowing north-eastwards from the Bellingshausen Sea, around the
west coast of South Georgia, into the South Atlantic Ocean. In this water during the
season 1931-2 Over 10,000 individuals were taken in the upper and lower of the two
towings together. In the season 1932-3 the catches were smaller, and over 10,000 in-
dividuals were only taken at two stations, one in the Bellingshausen Sea current and
one in sub-Antarctic water between the Falklands and South Georgia. At the remaining
station the catches usually amounted to between 5000 and 10,000 individuals. R. gigas
constituted more than 75 °%, of the copepod catches in both Antarctic and sub-Antarctic
water in the Drake Passage in the season 1932-3 (pp. 294, 308, 313).
3. The Weddell Sea is an area of scarcity of R. gigas, contrasting sharply with the
area of abundance in water of Bellingshausen Sea origin. In 1931-2 R. gigas amounted
to less than 15 per cent of the total catch in Weddell Sea water where the average tem-
perature of the surface 100 m. was less than 0° C. (p. 296). In the season 1932-3
this species formed less than 25 per cent in Weddell Sea water, of which the average
temperature of the surface 100 m. was less than o° C. and less than 15 per cent in water
with a temperature less than — 1-0° C. (p. 313). In both seasons the total catches in
Weddell Sea water with a temperature below — 1-0° C. amounted to less than 500 in-
dividuals in both nets.
4. During the summer months the species extended north of the Antarctic con-
vergence in the Falkland Sector, but in the winter it became restricted to Antarctic
waters and the convergence formed the northward limit of its range so far as the surface
250 m. is concerned (pp. 298-301).
RHINCALANUS GIGAS 359
5. The catches became progressively reduced in size during the winter months, and
after midwinter in the South Pacific Ocean, the species had practically disappeared from
the surface 250 m. (pp. 299-301).
6. Examination of the percentage of the total catch taken in the upper and lower nets
in the summer in the Falkland Sector, and in April in the South Indian Ocean, strongly
suggests that R. gigas undertakes seasonal vertical migrations similar to those of the
species investigated in the northern hemisphere. It spends the summer months within
the surface 100 m., and at the end of the summer descends below this level. At the end
of April it had sunk out of range of the 250-100 m. net. It reappears again in the surface
250 m. in the spring, and in November returns once more to the layer between o and
100 m. (pp. 301-4). This theory has been confirmed by the work of the ‘Discovery IT’
on her third commission (1933-5). Thus, while R. gigas spends the summer in north-
ward-flowing Antarctic surface water, it spends the winter months in the southward-
flowing warm deep water.
7. The species has two spawning periods during the year. One takes place in the
summer in Antarctic surface water from mid-December onwards (in the Falkland
Sector)—although the exact range of time covered by the spawning has not been fixed
(pp. 323-30). The summer generation produced by this spawning descends into the
warm deep water and spawns there probably in late May and the first half of June (pp.
338-40). This spawning produces the over-wintering generation which reappears in
October in the surface 250 m. mainly in stages iv and v (pp. 323-6, 341).
8. It seems that the over-wintering generation spends the months July, August and
September in warm deep water mostly in stages iv and v, but the stage reached by the
spring seems to depend on the temperature of the water in which development occurs,
since in the spring the winter generation reappears in sub-Antarctic water largely in the
adult condition and in stage v. In Antarctic water, however, it reappears largely as
stages iv and v, and in the coldest water, in the spring of 1931-2, comparatively large
numbers of stage iii were found (p. 324). The over-wintered generation which re-
appeared at the surface in the western Drake Passage in the warmer spring of 1932-3
was in a more advanced condition than that which reappeared in the colder spring of
1931-2 (p. 341).
g. The over-wintered generation comes to maturity in late November and December
around South Georgia (pp. 326, 343), and the approach of the spawning period is
heralded by the appearance of ripe eggs in the ovaries of the adult females (pp. 316—19)
and by an increase in the proportion of adult males in the lower nets (pp. 320-2).
10. In the Falkland Sector the summer spawning takes place in water of Bellings-
hausen Sea origin in the South Atlantic, western Scotia Sea and Drake Passage, within
an optimum temperature range not exactly fixed but probably between 1-0 and 4:0° C.
In the season 1931-2 it began in December in waters east of South Georgia and spread
later into the Scotia Sea and Drake Passage. In the season 1932-3 spawning probably
began earlier than in 1931-2 (pp. 326-30, 345):
11. No spawning at all took place, in 1931-2, in Weddell Sea water before the end of
II-2
°
360 ; DISCOVERY REPORTS
January at least. One station taken in this water in March 1933 might perhaps suggest
that a spawning may take place later in the season in warmer Weddell Sea water
(pp. 330-2, 349).
12. The Rhincalanus population of the Weddell Sea is probably an invasion from an
outside area and is carried into the Weddell Sea by warm deep water from the South
Atlantic or by the deep current from the South Indian Ocean which flows westwards
along the coast of Coats Land south of 66° S. (pp. 330-2, 349-51).
13. If no spawning at all takes place in the Weddell Sea the adult population found
there in the summer must result from the winter spawning in the South Atlantic, and
thus be six months old, or from the previous summer’s spawning, and thus be a year
old (p. 332).
14. In view of the different ages of the stock of Rhincalanus at different places at the
same time of year, it is suggested that spawning takes place in colder Antarctic water
later than in warmer water. There is thus a southward movement of the region of spawning
from northern warmer water to more southerly colder water as the season advances. At
temperatures below the optimum range for the spawning of the species the spawning is
delayed. This delay, it is suggested, is the result of retardation of development by reduced
temperatures. ‘The parent generation in colder water takes longer to attain maturity and
fails to spawn until either the temperature of the water has been raised to within the
spawning range by the seasonal southward movement of the isotherms or the population
has drifted into water of a suitable temperature for spawning (pp. 354-7).
15. Itis further suggested that temperatures below a certain limit—tentatively placed
between o and —1-0° C.—inhibit spawning altogether (p. 355).
LIST Or VILE RATU RE
Arpiey, R. A. B. and Macxintosu, N. A., 1936. R:R.S. ‘ Discovery’ IT. Discovery Reports (in press).
Brapy, G.5., 1883. Report on the Copepoda. Report on the Voyage of H.M.S. ‘Challenger’. Zoology, viu,
pt. XXIII, pp. 1-142, text-figs. 1-4, pls. 1-55.
1918. Copepoda. Australasian Antarctic Expedition, 1911-14, Sci. Rep., Series C (Zool. and Bot.),
V, pt. 3, pp- 1-148, 15 pls.
CaMPBELL, MitpreD H., 1934. The Life History and post-Embryonic Development of the Copepods, Calanus
tonsus (Brady) and Euchaeta japonica (Marukawa). J. Biol. Board Canada, 1, pp. 1-65, text-figs.
1-18.
Coxer, R. E., 1933. Arrét du développement chez les Copepodes. Bull. Biol. France Belgique, Lxvi, pp. 276-87,
text-figs. 1-2.
Deacon, G. E. R., 1933. A general account of the Hydrology of the South Atlantic Ocean. Discovery Reports,
VII, pp. 171-238, text-figs. 1-24, 3 pls.
1936. The Hydrology of the Southern Ocean. Discovery Reports (in press).
Farran, G. P., 1927. The Reproduction of Calanus finmarchicus off the South Coast of Ireland. J. du Conseil,
II, pp. 132-43, text-figs. 1-2 (Copenhagen).
1929. Crustacea. Part X. Copepoda. British Antarctic (‘Terra Nova’) Expedition. Nat. Hist. Report,
Zool., VII, pp. 203-306, text-figs. 1-37, 4 pls.
GIESBRECHT, W., 1902. Copepoden. Résultats du Voyage du S.Y. ‘Belgica’. Expédition Antarctique Belge,
Pp. 1-49, 13 pls. (Anvers).
i See ee ie te ng in a ee TN ae
i i i i i i ie i a ee”. aii ae ea as
————
RHINCALANUS GIGAS 361
Gran, H.H., 1902. Das Plankton des Norwegischen Nordmeeres, von biologischen und hydrografischen Gesichts-
punkten behandelt. Report on Norwegian Fishery and Marine Investigations, 11, pt. 2, No. 5,
Bergen, pp. 1-219, text-figs. 1-16, 1 pl.
Harpy, A. C. and Guntuer, E. R., 1935. The Plankton of the South Georgia Whaling Grounds and Adjacent
Waters, 1926-27. Discovery Reports, x1, pp. 1-456, text-figs. 1-193.
Kemp, S., Harpy, A. C. and Macxintosu, N. A., 1929. Discovery Investigations, Objects, Equipment and
Methods. Discovery Reports, 1, pp. 141-232, text-figs. 1-35, pls. vii—xviii.
Lezour, M. V., 1916. Stages in the Life History of Calanus finmarchicus (Gunnerus) experimentally reared by
Mr L. R. Crawshay in the Plymouth Laboratory. J. Marine Biol. Assoc., n.s., XI, pp. I-17, 5 pls.
in text.
MackinTOosH, N.A., 1934. Distribution of the Macroplankton in the Atlantic Sector of the Antarctic. Discovery
Reports, Ix, pp. 65~160, text-figs. 1-48.
—— 1935. Recent Antarctic Research undertaken by the ‘ Discovery’ Committee. The R.R.S.‘ Discovery IT’,
1933-35. Nature, 136, pp. 629, 630, 2 figs.
Murray, J. and Hjort, J., 1912. The Depths of the Ocean. London.
Nicuo ts, A. G., 1933. On the Biology of Calanus finmarchicus. I. Reproduction and seasonal Distribution in
the Clyde Sea area. J. Marine Biol. Assoc., n.s., xIx, pp. 83-109, text-figs. 1-4.
Orton, J. H., 1920. Sea Temperature, Breeding and Distribution in Marine Animals. J. Marine Biol. Assoc.,
N.S., XII, pp. 339-06, 1 text-fig.
OrtestaD, P., 1932. On the Biology of some Southern Copepoda. Hvalradets Skrifter (Norske Vid. Akad.,
Oslo), No. 5, pp. 1-105, text-figs. 1-37.
PAULSEN, O., 1909. Studies on the Biology of Calanus finmarchicus in the waters round Iceland, 1906. Medd.
fra Komm. for Havundersogelser, Ser. Plankton, 1, No. 4, pp. 1-21, 3 pls. (Kobenhavn).
RUNNSTROM, S., 1927. Uber die Thermopathie der Fortpflanzung und Entwicklung mariner Tiere in Bexiehung
zu threr geographischen Verbreitung. Bergens Museum Arbok Naturv., No. 2, pp. 1-67, 2 text-figs.
—— 1929. Weitere Studien tiber die Temperaturanpassung der Fortpflanzung und Entwicklung mariner Tiere.
Ibid., No. 10, pp. 1-46.
Ruup, J. J., 1929. On the Biology of the Copepods off Mére. Rapports et Proc. Verbaux du Cons. Perm. Int.
pour l’Explor. de la Mer, Lv1, pp. 5-84, text-figs. 1-8 (Copenhagen).
Scumaus, P. H. and Lennuorer, K., 1927. Copepoda. 4. Rhincalanus, Dana 1852. Deutsche Tiefsee
Expedition, 1898-9, xxIII, pp. 355~-400, text-figs. 1-29.
Scott, J., 1912. The Entomostraca of the Scottish National Antarctic Expedition, 1902-1904. ‘Trans. Roy.
Soc. Edinburgh, Lxvii1, pp. 521-99, 14 pls.
Somme, J. D., 1934. Animal Plankton of the Norwegian Coast Waters and Open Sea. 1. Production of Calanus
finmarchicus (Gunner) and Calanus hyperboreus (Kréyer) in the Lofoten Area. Fiskeridirektoratets
Skrifter, Serie Havundersokelser (Report on Norwegian Fishery and Marine Investigations), Iv,
No. 9, pp. 1-163, text-figs. 1-45.
Srérmer, L., 1929. Copepods from the ‘ Michael Sars’ Expedition, 1924. Rapports et Proc. Verbaux du Cons.
Perm. Int. pour l’Explor. de la Mer, Lv1, No. 7, pp. 1-57, text-figs. 1-18 (Copenhagen).
WOoLFENDEN, R. N., 1908. Crustacea. VIII. Copepoda. National Antarctic Expedition, 1901-1904. Natural
History, Iv, pp. 1-46, 7 pls.
— 1911. Die marinen Copepoden der Deutschen Siidpolar Expedition, 1901-1903. Deutsche Siidpolar
Expedition, xu, Zool. 1v, pp. 139-380, text-figs. 1-82, pls. xxii—xli.
362 j DISCOVERY REPORTS
Table Ia. Hauls of the 1-m. net from which the Copepoda were examined
Falkland Sector, 1931-2
Position Upper net Lower net Average
temp.
o—-iI00om.
Depth Time I
m. °
Depth
m.
Long. Time
Falkland Islands to Magellan Straits, Nov. 1931
60° 00:0’ W | 109-0* | 0641-0701 — —
68° 59:1’ W | 125—-0* | 1700-1720 | 250—-144* | 1700-1722
64° 14:0’ W | go-o* | 0244-0302 — —
66° 05:0’ W | 79-0* | 1100-1112 — —
Western Drake Passage, Nov. 1931
150-0* | 2146-2205 | 250—196* | 2146-2220
108—o* | 1213-1233 | 270—190* | 1213-1246
124—0* | 2250-2311 | 310—170* | 2250-2313
102-0* | 2306-2325 | 256—-194* | 2306-2337 : Antarctic
62-0* | 2318-2338 | 246-170* | 2318-2349 = convergence
84-0* | 2235-2255 | 300—-140* | 2334-0005
Ice edge (Southern Drake Passage), Nov. 1931
73° 28:8’ W | 62-0* | 2150-2220 | 216—168* | 2150-2223
69° 24:8’ W | 109-0* | 2301-2321 | 248-154* | 2214-2345 : 4 mile from
pack-ice
64° 32:0’ W | 121-0* | 2219-2239 | 172-85* | 2133-2203 |°
61° 03:2’ W | 123-0* | 2226-2246 | 286-126* | 2143-2212
Eastern Drake Passage and South Atlantic, Nov. 1931
55° 54:1’ W | 149-0* | 2231-2311 | 264—-108* | 2148-2219
55° 47:1 W | 117-0* | 1138-1158 | 260-104* | 1054-1125 : «Antarctic
55° 50°5' W | 125-0* | o121-0141 | 306—124* | 0034-0104 convergence
54° 13:8’ W | 180-0* | 2315-2335 | 204-138* | 2231-2300
54° 03°5’ W | 166-0* | 1334-1354 | 250-160* | 1253-1322
Western Scotia Sea and South Atlantic, Dec. 1931
49° 17°7' W | 104-0* | 2124-2145 | 269—138* | 2124-2158
49° 12°5’ W | 165-0* | 2346-0007 | 280—-110* | 2258-2328 Antarctic
° , | <—
48° 59:0’ W | 130-0* | 2226-2246 | 210—130* | 2142-2212 ; convergence
48° 50:5’ W | 156-0*% | 2324-2344 | 320-126* | 0000-0030
48° 39:9’ W | 119-0* | 0037-0057 | 260—-100*}| 2352-0022
60° 21:6’ S | 48° 40:2’ W | 176—-0* | 2339-2359 | 260-140* | 2255-2325
Eastern Scotia Sea, Dec. 1931
59° 46°3’S | 45° 30°5’ W | 151—-0* | 0027-0047 | 290—-140* | 2341-0011
59° 35°59 | 42° 40:1’ W | 124-0* | 2314-2335 | 280-130* | 2230-2300
58° 11:3’ S | 41° 16:3’ W | 104-0*% | 2049-2109 | 206-114* | 2007-2036
58° 51:0’ S | 36° 54:0’ W | 102-0* | 2055-2115 | 230-110* | 2011-2041
57° 02°6'S | 36° 47-2’ W —_ — 270-118* | 1120-1222 Near drift ice
| and bergs
56° 20:6’ S | 36° 34:7’ W | 119-0* | 2220-2240 | 248-120* | 2135-2206 2 Abundant di-
atoms in sur-
face haul
55° 1574'S | 36° 16:4’ W | 144-0* | 0814-0834 | 342-150* | 0729-0800
* Rhincalanus gigas present.
+ Closing depth of lower haul estimated.
RHINCALANUS GIGAS
Table I a (cont.)
363
* Rhincalanus gigas present.
Position Upper net Lower net Average
St: Date | temp. Remarks
Lat. Long. pene Time eee Time |° a
1931 South Georgia area, Dec. 1931
774 | 16. xii | 52° 43°4’ S | 37° 17°5’ W | 137—-0* | 0812-0832 | 250-100*4| 0727-0757] 0-81
775 | 16. xii | 50° 48-3’ S | 37° 21-6’ W | 106-0* | 2225-2245 | 288-112* | 2143-2213 — Antarctic
776 | 17. xii | 49° 29°0’ S | 37° 22°5’ W | 120-0* | 1411-1431 | 356-170* | 1326-1355 4:21 | convergence
778 | 18. xii | 52° 05°7’S | 35° 22-7’ W | 119-0* | 2344-0004 | 252—-102* | 2259-2329 1°70 | Very abundant
| diatoms in sur-
face haul
779 | 19. xii | 53° 27°3°S | 34° 31°8’ W | 146-0% | 1244-1304 | 280—-140* | 1202-1232 O57
780 | 19. xii | 54° 23:0’ S | 33° 54:5’ W | 114-0* | 2317-2337 | 202-133* | 2233-2303 | —o-12 | Very abundant
| diatoms in sur-
face haul
788 | 21. xii | 54° 00°2’S | 40° 24-7’ W | 119-0* | 1834-1854 | 280—100* | 1754-1824 o-9l
South Atlantic, Jan. 1932
795 | 6.1 | 53° 44:6’S | 31° 02-1’ W | 124-0* | 2314-2334 | 310-124* | 2230-2300 | —0-22
796| 7.i | 53° 47:1’S | 28° 14:9’ W | 131-0* | 1240-1300 | 248—-102* | 1200-1230 1°42. | Some diatoms in
surface haul
797 | 7-1 | 54° 44:7’ S | 27° 20:8’ W | 153-0* | 2101-2121 | 250-122* | 2016-2046 0°25
798 | 8.i | 54°50°5’S | 25° 56:0’ W | 100-0 | 1027-1038 | 242—116* | 0918-0948 061
799 | 8.1 | 54° 43°7'S | 24° 30:0’ W | 131-0*% | 2351-0011 | 334—-130* | 2309-2339 o-9l
801 | 9.1 | 54° 26:4’S | 21° 11:1’ W | 104—-0* | 1938-1958 | 210—-128* | 1857-1927 088
802 | 10.1 | 54° 15:0’S | 19° 11-1’ W | 126-0* | 0721-0741 | 320-70* | 0633-0704 1'97
803 | 10.1 53° 24°7°S | 22° 19:1’ W | 120-0* | 2211-2231 | 308-130* | 2130-2200 2°70
Weddell Sea, Jan. 1932
804| 11.1 | 55° 30°3’S | 21° 02:6’ W | 130-0* | 2348-0008 | 290—-104* | 2300-2330 | — 0°03 | Abundant di
806 | 12.i | 57° 27-2’S | 21° 28-8’ W | 116-0* | 2254-2314 | 216—-104* | 2254-2314 0:02 ae
807 | 13.1 58° 47:7’ S | 21° 40°4’ W | 137-0* | 1150-1210 | 262-84* | 1109-1139 | —0°85 atoms.12
808 | 13.1 | 59° 56:0’ S | 22° 20-7’ W | 120-0* | 2316-2336 | 250-100* | 2236-2306 OIL surface haul
809 | 14.i | 61° 09:9’ S | 22° 36:9’ W | 128-0* | 1306-1326 | 196—104* | 1221-1251 | —1°6 Fairly abundant
| diatoms in
surface haul
810 | 14.1 61° 30°7’ S | 23° 12:3’ W | 166-0* | 2001-2121 | 304-130* | 2019-2049 — Among light ice
811] 15.1 | 62° 44:0’S | 23° 18-4’ W | 113-0* | 1939-1959 | — —_— | —1°73
812|16.i | 64° 12°5’S | 22° 57-0’ W | 137-0% | 1252-1312 | 318-102* | 1212-1242 | — 1°55
813 | 16.1 64° 55-9’ S | 23° 13:0’ W | 135-0* | 2301-2321 | 340-100*}| 2215-2245 | —1:60
815 | 17.i | 66° 57-3’ S | 22° 38-3’ W | 140-0* | 2350-0010 | 314-188* | 2310-0010 | — 1°53
816 | 18.1 | 68° 09-6’ S | 22° o1-7’ W | 133-0* | 1422-1442 | 256-80* | 1340-1410 | —1°35
817 | 19.1 | 69° 59:6’ S | 23° 53:0’ W | 132-0* | 0856-0916 | 260-126 | 0808-0838 | —1:34 | At edge of heavy
| pack-ice
Weddell Sea, Eastern Scotia Sea, Jan. 1932
818] 20.i | 68° 11°3’S | 24° 52:8’ W | 77-0 | 1126-1146 — — _—
819 | 20.1 | 67° 23:9’ S | 25° 40-7’ W | 105-0* | 2027-2047 = — = [ :
820 | 21.1 65° 44:9’ S | 28° 29:9’ W | 110-0* | 2243-2303 | = | = | = (are PORES
822 | 23.1 | 63° 53-7’S | 33° 28-1’ W | 146-0*% | 2056-2116 | 244-130* | 2016-2046 | —
823 | 27.1 | 61° 24-4’ | 36° 03-6’ W | 179-0* | 1014-1034 | 312-1 19* | 0928-1001 | — 13 At edge of pack-
| | | ice
824} 27.i | 59° 57-4 S | 36° 06-6’ W | 157-0* | 2111-2131 | 300-104* | 2029-2059 — Abundant di-
atoms in surface
| haul
825 | 28.1 | 56° 31-2’ S | 36° 00°5’ W | 117-0* | 2015-2035 | 310—-100* | 2051-2121 | —
Falkland Islands to South Georgia, Feb. 1932
828 | 17. ii | 51° 44-3’S | 55° 57-0’ W | 141-0* | 2228-2248 | 250—-100*f} 2146-2216| 7-10
829 | 18. ii | 51° 42°8’S | 50° 31-7’ W | 140-0* | 2205-2225 | 270-84* | 2121-2152 | 5°42 Antarctic
ii | 52° 31-3’ S | 44° 51-3’ W | 117-0* | 2307-2327 | 356-140* | 2300-0011 | 4°15 convergence
B30 1973, 9/395 32-1, W | 130-0* | 2341-2401 250-1007} 2300-2330 2°74
+ Closing depth of lower haul estimated.
364 DISCOVERY REPORTS
Table I b. Hauls of the 1-m. net from which the Copepoda were exanuned
Falkland Sector, 1932-3
| | Position Upper net Lower net | Average
St: | Date | 5 : | ees Remarks
| —
Lat Long Dewi | ‘Time eeu Time |° se
iy m. :
| |
1932 Falkland Islands to Magellan Straits, Oct. 1932
979 | 15.x | 51° 00:0’ S | 62° 36:3’ W | 117-0* | 1109-1129 — — 5°41
980 | 15.x | 51° 00°6’S | 64° 44:1’ W | 104-0 | 2206-2223 a = 4:96
981 | 16.x | 51° 0171'S | 66° 58:2’ W| 80-0 | 0916-0936 — — 5°80
Western Drake Passage, Oct. 1932
983 | 24.x | 55° 10:0'S | 76° 04°7’ W | 121-0* | 2250-2310 | 300- 80* | 2250-2320 5°83
984 | 24.x | 55° 14:4’S | 77° 48-6’ W| 99-0* | 1105-1125 | 240-100* | 1105-1135 5°06
985 | 24. | 55° 22:2’S | 79° 24°5’ W | 113-0* | 2209-2229 | 290-110* | 2209-2239 | 4:96
986 | 25.x | 56° 28:9 S | 79° 28-2’ W | 102-0* | 1100-1120 | 244-114* | 1100-1130] 4:91
988 | 26.x | 59° 19:0’ S | 79° 39°8’ W | 88-0* | 2240-2300 | 224— 74* | 2240-2310| 3:86
990 | 27.x | 61° 56:3’S | 79° 57:0’ W | 96-0* | 2229-2249 | 270-100*T| 2229-2259 | 3-08 Antarctic
992 | 28.x | 64° 19:2’S | 80° 06:0’ W | 100-0* | 2159-2219 | 270-110* | 2159-2229 | — 1°54 convergence
994 | 29.x | 66° 45:7’ S | 80° 19:8’ W | 113-0* | 2159-2219 | 270— go0* | 2159-2229 | — 1-70
995 | 30.x | 67° 06:2’ S | 79° 55:8’ W | 125-0*f| 0342-0402 | 320-120* | 0342-0412 —- In light pack-
| | ice
Ice edge (Southern Drake Passage) and Bransfield Straits, Oct-Nov. 1932
996 | 30.x | 66° 53-8’S | 78° 52:6’ W | 100-0 | 1646-1706 | 350— 90* | 1646-1716 —
o-5*§) 1645-1720
997 | 30.x | 66° 37:4’ S | 78° 23:6’ W o-5§ | 2025-2055 — — —
o-10§| 2025-2055
999 | 31.x | 66° 55:8’ S | 73° 51°5° W | 151-0* | 2207-2227 | — — —_—
0-5 | 2207-2237 |
1000 | 1. xi | 65° 06:6’ S | 71° 39°7’ W | 128-o* | 1108-1128 | 300-110* | 1108-1138 | — 1-63
roo1 | 1.xi | 64° 53:8’ S | 68° 43:9’ W | 95-0* | 2143-2203 | 230- 66* | 2143-2213 | —1°89
1003 | 2. Xi 63° 40°7’S | 63° 03°7’ W | 115-0* | 2050-2110 | —_— —_— — 1-28
1004} 5.xi | 63° 02:2’S | 60° 25:5’ W | 123-0 | 1259-1319 | 320-120* | 1259-1329 | —0°73
1005 | 5. xi | 63° 09:0’S | 60° 11:0’ W | 109-0 | 1615-1635 | 300-100* | 1615-1645 | — 1-19
1006 | 5. xi | 63° 16-7’S | 60° 06:5’ W | 115-0 | 1940-2000 | 320-152 | 1940-2010 | —0°93
1009 | 6. xi | 62° 55°9’S | 58° 00°3’ W | 155-0* | 0545-0605 | 300-120} | 0545-0615 | —
Eastern Drake Passage and South Atlantic, Nov. 1932
torr | 6.xi | 62° 40:4’S | 56° 19:5’ W | 100-0* | 1214-1234 | — — —1°48
1013] 6. xi | 61° 5775S | 56° 20:1’ W | 93-0 | 2210-2230 | 314-140* | 2210-2240 | —1-11
to14| 7. xi | 61° 26-8’ S | 56° 19-7’ W | 144-0 | 0320-0340 | _— — —I-o1
1015 | 7.xi | 58° 53:2’S | 56° 18-6’ W | 128-0* | 2210-2230 | 350-120* | 2210-2240 | — 0-49
1017 | 8.xi | 56° 00-2’ S | 56° 07-6’ W | 110-0* | 2216-2236 | 350-150* | 2216-2246 0°43 Antarctic
1019 | 9. xi | 53° 22°6’S | 56° 02:0’ W | 119-0* | 2143-2203 | 320-110* | 2143-2213 4:96 convergence
South Atlantic, Nov. 1932
ro2r | 13. xi | 51° 20:1’ S | 55° 20:1’ W | 120-0* | 2119-2139 | 315-150* | 2119-2149 5°23
1023 | 16. xi | 50° 48:9’ S | 51° 32:9’ W | 112-0* | 2152-2213 | 318-130* | 2152-2223 4°93
1025 | 17. xi | 50° 18:3 S | 47° 12:4’ W | 140-0* | 2137-2157 | 400-160* | 2137-2207 | 352 Antarctic
| | | convergence
Western Scotia Sea and South Atlantic, Nov. 1932
1027 | 18. xi | 51° 19°8’S | 44° 40°8’ W | 100-0* | 2139-2159 | 300-125* | 2139-2209 | 2°54
1029 | 19. xi | 54° 20°7’S | 44° 35°8’ W | 100-0* | 2158-2218 | 300-150* | 2158-2228 | 0-92
1031 | 20. xi | 56° 56-4’ S | 44° 32:3’ W | 149-0* | 2153-2213 370-104* | 2153-2223 0°52
1033 | 21. xi | 59° 38:2’ S | 44° 30:8’ W | 113-0* | 2318-2338 | 270-100* | 2318-2348 | —o-1o
1034 | 24. xi | 60° 57:6’ S | 44° 39:8’ W | 165-0* | 1220-1240 _ — —1:26
1035 | 24. xi | 61° 56:2’S | 44° 44:2’ W | 100-0* | 2219-2239 | 274-116* | 2219-2249 | —1:26 | Among drift-
0-5§ | 2220-2250 ice
|
*
Rhincalanus gigas present.
t Net failed to fish properly.
+ Closing depth of lower net estimated.
§ Net towed horizontally.
RHINCALANUS GIGAS 365
Table I } (cont.)
| Position Upper net Lower net | Average
St. | Date | temp: Remarks
D : —~ |
| Lat. Long. | es | ‘Time eke | Time [ aa |
co sige ee
1932 Scotia Sea and South Atlantic (east of South Georgia), Nov.—Dec. 1932
I
°
Bx
H
N
a
B
i | 60° 31-3’ S | 36° 19°5’ W | 84-0* | 2110-2130 | 250-100* | 2110-2140 | —1-27 |
1044 | 27. xi | 60° 00°6’S | 32° 21-6’ W | 117-0* | 2108-2128 | 296—-100* | 2108-2138 | —1-41_ |
1045 | 29. x | 58° 33:0'S | 27° 04:9’ W | 100-0* | 1036-1056 | 256-110* | 1036-1106 | — 1°64 |
|
|
1038 | 25. xi | 61° 39°4’S | 40° 00°3’ W | 151-0* | 2227-2247 | 375-110* | 2227-2247 | —1-24 |
(eee pack-ice
mR.
1047 | 30. x1 | 58° 26:9’S | 26° 09:3’ W | 84-0* | 0438-0458 | 230— 86* | 0438-0510 | — 1°35
1048 | 30. xi ee 32:2’ S | 27° 21-9’ W | 119-0* | 1547-1607 | 340-110* | 1547-1617 | —o-'81
1050 | 1. xii | 53° 46:6’ S | 31° 09:2’ W | 103-0* | 2212-2232 | 295—-104* | 2212-2242 | —0°54
1052) 2. xii | 52° 10°1’ S | 33° 22-2’ W | 133-0* | 2104-2124 | 338-130* | 2104-2134 | 0:86 |
1054 | 3. xii | 50° 07°8’S | 35° 48:6’ W | 98-o0* | 2226-2246 | 250- go* | 2226-2256 2-48
1056| 4. xii | 50° 18:0’ S | 37° 04°5’ W | 100-0* | 2139-2159 | 340-150* | 2139-2209 3°33 | Diatoms fairly
abundant in
surface haul
South Georgia, Dec. 1932
1063 | 11. xii | 52° 04°7’ S | 38° 08-8’ W | 128-0* | 1231-1251 | 334-114* | 1231-1301 | —_
1066 | 12. xii | 53° 53°6’ S | 40° 30°5°W | 94-0* | 0228-0248 | 276—105* | 0228-0258 —
1073 | 13. Xii | 54° 59:6’ S | 36° 38-9’ W | 117-0* | 0628-0648 | — — — Diatoms fairly
| | | | | abundant
|
1076 | 13. xii | 54° 24:0 S | 34° 071’ W | 1r0-0* | 2134-2154 | 270-100* | 2134-2204| 0:66 x oF
Scotia Sea, Dec. 1932—Jan. 1933
1083 | 30. xii | 54° 37°5’S | 40° 35-9’ W | 125-0* | og19-0939 | 250-100* | 0919-0940 | —
1085 | 31. xli | §7° 000’ S | 41° 53-9’ W | 146-0* | og18-0938 | 250-125* | 0918-0948 |
1088 | 1.i | 60° 12:1’S | 44° 29-9’ W | 100-0* | 2149-2209 | 260—120* | 2149-2219 | —0'4
Bransfield Straits, Jan.—Feb. 1933
1097 | 31.1 | 61° 40-1’ S | 50° 27-0’ W | 119-0* | 0931-0951 | 280—124* | 0931-1001 —
|
IIor | 1.ii | 61° 50°8’S | 54° 42-9’ W | 153-0 | 2301-2321 | 250-I100* | 2301-2331
At edge of
loose pack-ice
convergence
1108 | 4.ii | 62° 22°3’S | 58° 30:5’ W | 134-0 | 1321-1341 | 290-100* | 1321-1351 0-02
III0| 4.ii | 62° 57°5’S | 57° 38-6’ W | 135-0* | 2133-2153 | — — | —0'84
Drake Passage, Feb. 1933
1115 | 6.ii | 60° 39:2’S | 61° 31:9’ W | 119-0 _| 2215-2235 | 315-130* | 2215-2245 058
1116| 7.ii | 59° 17°2’S | 61° 04:4’ W | 110-0* | 0926-0946 | 270-115* | 0926-0956 | ae |
1117] 7. ii | 57° 46-1’ S | 60° 30°9’ W | 100-0* | 2245-2305 | 320-120* | 2245-2305 | 4°11 | Antarctic
1119| 8.11 | 55°07°9’S | 59°.18°5’ W | 100-0* | 2247-2307 | 330-100* | 2247-2317] 6:09 | convergence
South Atlantic, Feb. 1933
1122 | 20. ii | 52° 04:6’S | 50° 54:5’ W | 70-0* | 0928-0948 | 190-115* | og28-0958| — |
1123 | 20. ii | 52° 12:6’ S | 48° 25-3’ W | ro2—-o* | 2312-2332 | 250-100* | 2312-2342 4°74 oe
|
1125 | 21.ii | 52° 21°5’S | 43° 34:5’ W| 97-0* | 2222-2242 | 290-100* | 2222-2252 3°19
1127 | 23. ii | 52° 43°7’S | 37° 12:5’ W | 100-0* | 0604-0624 | 260— go* | 0604-0634 2:08
1131 | 24. ii | 54° 22:6’ S | 34° 08-4’ W | 100-0* | 1619-1639 | 250-106* | 1619-1649 |
Weddell Sea, March 1933
132-0* | 2237-2257 | 335-100* | 2237-2307 | 076
2.11 |'552 55°55 | 32. 15°6° W
3. iii | 57° 21-1’ S | 27° 09°9’ W | 104—-0* | 2202-2222 | 310-110* | 2202-2232 o-21
1142] 4. iii | 58° 44:3’S | 22° 30:9’ W| 93-0* | 2315-2335 | 260-110* | 2315-2345 1°02
5. iii | 59° 44°5’S | 17° 30°8’ W | 119-0* | 2221-2241 | 340-100* | 2221-2251
1146 | 6—7. iii | 61° 00-2’ S | 12° 03:8’ W | 104-0* | 2344-0004 | 290-110* | 2344-0014 | —0'58 |
1148] 9. iii | 63° 52:0’S | 0° 54:9’ W | 117-0* | 2324-2344 | 330-100* | 2324-2354 | —0°74
II50 | 10. iii | 65° 21°6°S | JD ayes]! |S gi—-o* | 2219-2239 | 270-100* | 2219-2249 | —o:08
T152 | 11. iii | 68° 03:0'S | 8° 03:0’ E | 115-0* | 2304-2324 | — | _ —-
1153 | 12. iii | 69° 22-0°S. | 9° 37°5’E | 117-0* | 0925-0945 | 365-110* | 0925-0945 — | Among streams
| of pack-ice
|
9
w
I
South Atlantic, March 1933
1161 | 19. iii | 50° 23:1’ S | 13° 55:2’ E | go-0* | 1621-1641 | 340-150* | 1621-1651 | sacle |
* Rhincalanus gigas present.
D XIII
366
DISCOVERY, REPORTS
Table Ic. Hauls of the 1-m. net from which the Copepoda were examined
Circumpolar cruise, February to October 1932
Position Upper net Lower net Average
St. | Date tee Remarks
Lat. Long. De Time DeeEe Times ia a
ene m. .
1932 South Georgia to Cape Town, Feb.—Mar. 1932
833) 2251 | 53° 58°37S|| 35° 50:0: W || 173-0* | 2232-2252 — — —
834 | 23. ii | 52° 17:1’S| 31° o1:0’ W | 146-0*% | 2118-2138 | 250-100*}) 2031-2102 — Antarctic
835) 255i1 || 492 1355.9) 220 20:2) Wi TI5—o) | 1017-1037, = — —_ convergence
836 | 27. ii | 45° 28:0'S | 11° 40-4’ W | 102-0* | 0924-0944 | 250-100*}| 0959-1028 _
837 | 27.ii | 44° 44:0'S | 09° 38:0’ W | 125-0 | 2025-2055 | 250-100} | 2025-2055 _
838 | 28. ii | 42° 56:0'S | 04° 52:2’ W | 137-0 | 2058-2118 | 250-100*f| 2016-2046 —
839 | 29. ii | 41° 04°4'S | 00° 14:3’ W | 132-0 | 2104-2124 | 250-100} | 2019-2049 —_
840| 1. iii | 39° 2170S | 04° 20°5’E | 101-0 | 2059-2119 | 250-100} | 2017-2047 —
841 | 2. iii | 37° 46°0°S | 08° 39:3’ E | 130-0 | 2053-2113 | 320-140 | 2013-2043 —_—
842 | 3. iii | 36°04:8’S | 13° 34°5’E | 155-0 | 2050-2110 — — —
| 280-0 | 2009-2049
Cape Town to Enderby Land, April 1932
844) 8.1v | 35° 10:3°S| 19° 061° E | 155-0 | 2057-2117 — — 17°13
845 | 9. iv | 38° 08:0’S | 20° 56-1’ E — _— 242-180 | 2328-0000] 16:43
846 | 10. iv | 40° 41°3S | 23° 02:0’ E | 128-0 | 0230-0250 | 370-170 | 0146-0216] 14°52 Antarctic
847 | 11. iv | 43°07°4’S | 25° 04:6’E | 119-0 | 0059-0119 | 270-196 | Co15-0046| 14°51 convergence
848 | 12. iv | 45° 48-4’S | 27° 13:6’ E | 117-0 | 0037-0057 | 270-166* | 2355-0025 6-86
849 | 14.1v | 48° 14:6°S | 29° 23:7’ E 71-0 | 0529-0549 | 210-125* | 0530-0600 7°90
850 | 15. iv | 50° 43'8’S | 31° 44:0’ E_ | 100-0* | 0528-0548 | 254—-140* | 0528-0558 1°70
851 | 17. iv | 56° 22:1'S | 37° 22:3’ E | 125-0* | 0411-0431 | 320—190* | 0411-0431 I'Io
852 | 18. iv | 58° 39°:5’S| 40° 03:9’ E | 119-0* | 0429-0449 | 370-155* | 0345-0415 0°24
853 | 19. iv | 61° 00:2’S | 43° 11-1’ EE | 119-0* | 0435-0455 | 190-108* | 0355-0425 | —0°33
854 | 20. iv | 63° 30°2’S | 46° 24:9’ E |. 119-0* | 0342-0402 | 248— 94* | 0255-0330 | —0-16
855 | 20. iv | 65° 15:0'S | 48° 43:7’E | 125-0* | 2310-2330 | 280-154* | 2310-2340 | —1°64 Among streams
of drift-ice
Enderby Land to Fremantle, April-May 1932
856 | 22. iv | 61° 06:6’S | 53° 39:8’ E | 89-0* | 2230-2250 | 224-120* | 2230-2310] 0:07
857 | 23. iv | 60° 40'1’S | 59° 23:7’ E | 130-0* | 0212-0232 | 262-140* | 0132-0202 | — 0-33
858 | 24. iv | 60° 1071'S | 63° 54:8’ E 88—o* | 2336-0006 | 264—130* | 2336-0006 0°33
859 | 25.iv | 59° 1971'S | 68° 51:8’ E | 100-0* | 2351-o011 | 210-140* | 2351-0023 0-60
860 | 26. iv | 57° 56-4°S | 73° 58-8’ E | 119-0* | 2349-0009 | 300—100* | 2349-0020 0°46
861 | 27. iv | 56° 28:9'S | 79° 18:2’ E | 109-0* | 0019-0039 | 254—110* | 0019-0049 0:66
862 | 28. iv | 55° 33°8°S | 83° 00-4’ E | 102-0* | 2313-2333 | 220— 98* | 2313-2343 1°75
863 | 29. iv | 54° 15°35 | 88° 22:-4’E | go-o* | 0127-0147 | 200— 82* | 0127-0159 1°65
865 | 3.v | 52° 48:-4°S | 94° 56:0’ E | 116—o* | 0620-0640 | 290—150*}| 0711-0741 =
S66))|) sienv, 1|/5ie 22-0098 OO" 20240155 98-0 | 0334-0354 | 284-110* | 0334-0404 3°58 Antarctic
867 | 2.v | 49° 25°5°S| 98° 21:8’E | 139-0 | 2313-2333 | 330-150* | 2313-2343 5°35 convergence
868 | 3.v_ | 46° 55:0’S | 100° 45-6’ E g8-o | 2237-2257 | 240-100 | 2237-2308 6:25
869 | 4.v_ | 43° 56°5’S | 103° 24°3’ E 68-0§ | 0030-0050 | 240-120 | 0030-0100| 10°64
870 | 5.v | 41° 41-7’S | 105° 16:0’ E | 95-0 | oo51-o111 | 250- 90 | 0051-0123 | 10°64
871 | 6.v | 39° 32:1’S | 107° 06:4’ E QI-o | 0152-0212 | 240-100 | 0152-0222| 12°56
872 | 7.v | 37° 09:1’S | 108° 47-2’ E | 128-0 | 2258-2318 | 300-146 | 2258-2328 | 15°59
873) 83.) Nia4e ror 1S) roe are —_ _ 220-110 | 2218-2248 | 18-96
* Rhincalanus gigas present.
{ Closing depth of lower net estimated.
+ Depths estimated.
§ Net fished for some time near surface.
RHINCALANUS GIGAS 367
Table I c (cont.)
Position | Upper net Lower net | Average
an = | temp: Remarks
| | lo— |
Spt | sires yee ot Pcie ieee ae
m. | m. e
Long.
al
©
w
N
Fremantle to ice edge, May 1932
114° 42°5°E | 102-0 | 0001-0022 | 250-100 | o001-0031
| 115° 38:6’ E | 125-0 | 2343-0003 | 294— 80 | 2343-0013 |
| 116° 46:5’ E 86-0 | 2353-0013 | 200- 94 | 2353-0026 |
117° 50°8’ E | 110-0 | 0002-0022 | 265— go_ | 0002-0032
119° 00°3’E | 119-0 | 2231-2251 | 260-100 | 2231-2301 : Antarctic
| 120° 28-6’ E | 102-0 | 2318-2338 | 210- 80 | 2318-2349 | : convergence
122° 03°8’ E 89-0* | 2230-2250 | 210— go* | 2230-2302
124° 04:8’ E | 122-0* | 0016-0036 | 270—- go0* | 0016-0046
125° 54:9’ E | 116-0* | 2334-2354 | 280-120* | 2334-0004
127° 52:9 E | 133-0* | 2353-0013 | 302-100* | 2353-0023
130° 07:0’ E | 86-o0* | 2119-2139 | 235-115* | 2119-2149 In streams of
120-0* | 2202-2222 | very light
pack-ice
44444 <4 <4 <4 4 4
Ice edge to Melbourne, May—June, 1932
131° 38°4’ E | 106-0* | 0037-0057 | 290- go* | 0037-0107
133), 18:52 5) ||| (08—0* | 2312-2332 240-1 10* | 2312-2341
135° 10°5’ E | 121-0* | 2322-2342 | 260- go* | 2322-2352 | 2 Antarctic
137° 00°4’ E 93-0 | 2245-2305 | 220-100 | 2245-2320 | convergence
|
138° 35°3° E | 100-0 | 2336-2356 | 260-100 | 2336-0006 |
139° 50°0’ E QI-O | 2307-2327 | 235-105 | 2307-2345 |
143° 38:4’ E | 80-0 | 2329-2349 | 250-110 | 0022-0052
Melbourne to ice edge, June 1932
148° 56:0’ E | 117-0 | 0107-0127 | 315-120 | 0107-0137
149° 32:2’ E | 128-0 | 2226-2246 | 310-120 | 2226-2256
117-0 | 0000-0020 — —
330-0 | 0000-0030 — —
135-0 | 2227-2247 | 340-140 | 2227-2257 |
120-0 | 0940-1000 | 330-150 | 0940-I0I0 |
I3I-O | 0037-0057 | 370-140* | 0037-0057 | Antarctic
104-0 | 2222-2242 | 330-130* | 2222-2252 ; | convergence
114-0* | 2323-2343 | 320-138* | 2323-2353
100-0* | 2324-2344 | 386-142* | 2324-2354
— | — 290-I10*}) og59—-1029 In soft new ice
Ice edge to New Zealand, June-July 1932
155° 37°’ E_ | 106-o* | 2026-2046 | 300-110* | 2026-2057 |
160° 23:1’ E_ | 128-0* | 2250-2310 | 306-130* | 2250-2320 | : Antarctic
162° 23:1’ E | 123-0 | 2316-2336 | 320-100* | 2316-2346 convergence
163° 52°2’E | r14-of | 2145-2205 | 250-100 | 2145-2206
163° 49°4’ E | 121-0 | 0727-0747 | 338-192 | 0727-0757
163° 41:4’ E | 100-0 | 0618-0638 | 240-138 | 0618-0658
165° 46:2’ E gs—o | 0720-0740 | 220- 95 | 0720-0750
167° 55:5’ E | 110-0 | 0743-0803 | 282-126 | 0743-0813
170° 12:8’ E 81-0 | 0744-0804 | 198-100 | 0744-0814
* Rhincalanus gigas present. + Depths estimated.
|| Calculated from observations at St. 912.
368
Position
DISCOVERY REPORTS
Table I c (cont.)
Upper net
Lower net
|
Long.
Depth
| Time
m
Depth
m.
Time
Average
temp.
o-I0om.
ray
Remarks
-
°
mH OR
vO
© ON AMBWW HH
54° 02°8’S
522 OL-Ta1S)
49° 42:1 S |
47° 16:9'S
44° 40°3'S |
41° 0371'S
42° 30:0 S
45° 361°S
55° 26-7 S |
56° 22°9'S |
59° 21°8’ S |
61° 47:°8'S
63° 57°0'S
61° 29°9' S |
59° 22:0 S |
57, 18:2 S
55° 18:4'S |
|
| 153° 57:2’ W
South Pacific Ocean, Aug.—Oct. 1932
176° 14:8’E |
179° 06°4’ E
177° 24°5° W
176° 21:3’ W
173, 26:9’ W
170° 13:0’ W
166° 55:9 W
163° 46:5’ W
160° 02:9’ W
158° 11:0 W
155° 42°4° W
150° 02:9’ W
146° 22:3’ W
25°4 W
13°2) W
33°2° W
25°1' W
142
139
135
132
IOI
94° 06-7’ W
89° 03:9’ W
84° 2975’ W
80° 08-1’ W
| 2149-2209
| 2322-2342
0947-1007
2237-2257
2345-0005
| 0008-0028
2334-2354
2330-2350
2219-2239
1351-1411
132-0
128-0
102-0*
128-0
117-0
I15—o*
117-0
102-0
117-0
97-9
100-0 1241-1301
gI-o
137-0
109-0
290-0*
0012-0032
0037-0057
2216-2236
2216-2246
0027-0047
2242-2302
2326-2346
2242-2302
2332-2352
0743-0803
2016-2036
2247-2307
| 1210-1230
| 2018-2038
2308-2328
2016-2036
1717-1737
2321-2341
2304-2324
2249-2309
2243-2303
* Rhincalanus gigas present.
350-110
356-130
255— 80
270-120
310-130
310-132*
320-120
300-130
340-130
280-100
260-114
240-110
290-134
325-144*
320-100*
320-128
250-100
310-132
250-100}
306-145
250-106
250—-100f
380-1 10*
340-120
300-122*
270-120*
314-114
290-104*
190— 84*
318-140
298-108*
2149-2219
2322-2352
0947-1018
2237-2307
2345-0015
0008-0038
2334-0004
2330-0000
2219-2249
1351-1421
1241-1315
0012-0042
0037-0107
2307-2337
0027-0057
2242-2312
2326-2356
2242-2312
2332-0002
0743-0813
2016-2046
2247-2317
I210-1240
2018-2048
2308-2338
2016-2046
1717-1745
2321-2352
2304-2334
2249-2319
2243-2313
+ Depth estimated.
Antarctic
convergence
Near edge of
light pack-ice
Among scat-
tered floes
Hauls from
325-144 and
290-0 m. ana-
lysed together
Antarctic
convergence
Antarctic
convergence
Table Il. Approximate depth of discontinuity between Antarctic
surface layer and warm deep water
Approx. Approx.
depth of dis-] | ; depth of dis-
continuity ‘ | continuity
(a) Falkland Sector 1931-2
I93I | |
246-170 | 250 780 | 19. xii 202-133
300-140 | 300 788 | 21. xii 280-100
216-168 | 150"*
248-154 200*
172— 85 200 795 bi 310-124
286-126 175% 796 wa | 248-102
264-108 125* 798 pit | 242-116
260-104 150* 799 -1 | | 334-130
306-124 400 802 sat | | 320- 70
210-130 250 804. na 290-104
320-126 350 806 oa 216-104
260-—? 100 200* 807 sil 262— 84
260-140 300 808 ai 250-100
290-140 350 809 gu 196-104
230-110 | 22h 812 | 16.1 318-102
270-118 250* 813 oa | 340-100
248-120 250 815 Bal 314-188
342-150 250* 816 Bi 256-— 80
250-100 175* 817 el 260-126
356-170 | 300* 823 al 312-119
352-102 175* 830 . i 356-140
280-140 175 831 | 20. i 250-100
(6) Falkland Sector 1932-3
1932
270-110 175% 1054 3. Xil 250— 90
270— go 150* 1056| 4. Xil | 340-150
230- 66 100* 1076 | 13. Xil 270-100
350-120 150*
350-150 T50™*
400-160 400 1088 : 100-0 260-120
300-125 400 I1I5 -i IIg-O 315-130
300-150 | 150** 1125 aii 97-0 290-100
370-104 200* 1127 50 100-0 260- go
270-100 100** 1131 ait 100-0 250-106
274-116 80** 1138 mitt 132-0 335-100
375-110 300* 1140 | 3-. ill 104-0 310-110
250-100 175* 1142 - lll 93-0 260-110
296-100 150* 1144 . iil 119-0 340-110
256-110 200* 1146 . ii 104-0 290-110
340-110 200* 1148 . lil 117-0 330-100
295-104 150* II50 . Ul gI-o 270-100
338-130 125
(c) Circumpolar Stations, April-September 1932
1932
254-140 | 300 890 | 29. v 98-0 240-110
320-190 | 200* 891 | 30. Vv I21I-O 260- 90
370-155 | 50" 904 | 20. vi 104-0 330-130
190-108 | 125* go5 | 21. vi 114-0 320-138
248-— 94 100* 906 | 22. vi 100-0 386-142
280-154 se g19 | 25. vi 128-0 | 306-130
224-120 125* g20 | 26. vi 123-0 | 320-100
262-140 T25e= 950 sibs 102-0 | 300-130
264-130 | L75* 951 abe 117-0 340-130
210-140 LS 956 Bib. 97-0 | 280-100
300-100 175 959 | Io. ix gI-o 240-110
254-110 175* 960 atx 137-0 | 290-134
270-— 90 200* 961 nix 109-0 325-144
280-120 | 200* | 26.3 128-0 | 300-122
302-100 125* | 28.1 II5-O | 314-114
235-115 Ou el 117-0 290-104
290- go 250*
* Deep hauls fished partly in warm deep water. ** Deep hauls fished wholly in warm deep water.
370 ; DISCOVERY REPORTS
Table III a. Horizontal distribution of Rhincalanus gigas
Falkland Sector, 1931-2
Upper net Lower net
Number
of R. gigas in
total Copepoda
Position of Ant-
arctic convergence
Total catch
o/
/
examined
Estimated
Fraction
examined
Estimated
examined
Fraction
examined
Falkland Islands to Magellan Straits, Nov. 1931
5 | 250-144
59 aa
8 =
Western Drake Passage, Nov. 1931
1/8 832 | 250-196 | 149 1/10 1,490 2,322
1/8 656 | 270-190 | 110] 1/1 IIo 766
1/10 | 2,020 | 310-170 136| 1/2 272 2,292
1/4 540 | 256-194 | 717| 1/4 2,868 | 3,408
1/20 | 12,740 | 246-170 | 514] 1/1 514 | 13,254
1/20 | 10,320 | 300-140 | 494] 1/8 3,592 | 13,912
Ice edge (Southern Drake Passage), Nov. 1931
311 | 1/8 2,488 | 216-168 | 786] 1/8 6,288 8,776
255 | 1/40 | 10,200 | 248-150 | 539] 1/10 | 5,390 | 15,590
246 | 1/50 | 12,300 | 172— 85 | 647] 1/50 | 32,350 | 44,650
140 | 1/5 700 | 286-126 | 322| 1/5 1,610 2,310
Eastern Drake Passage and South Atlantic, Nov. 1931
267 ler /r 367 | 264-108 | 290] 1/5 1,450 1,817
200 | 1/50 | 10,000 | 260-104 | 415 1/8 3,320 | 13,320
347 | 1/4 | 1,388 | 306-124 | 444] 1/25 | 11,100 | 12,488
383 1/5 | 1,915 | 204-138 | 416| 1/5 2,080 3,995
381 | 1/5 | 1,905 | 280-130 | 357] 1/10! 3,570 1 5,475
Western Scotia Sea and South Atlantic, Dec. 1931
75 Teter xil | TO4— ON 77. 30a let/ TON 7,730)||p200—03 5m lle 3070 leet) Sellmed, 055m |NO, 705m lezier
753 2. xii} 165-0 | 192 1/t 192 | 280-110 | 795 1/2 1,590 1,782 | 59°9
755 3. xii | 130-0 | 345 1/50 | 17,250 | 210-130 | 356 1/5 1,780 | 19,030 | 84:6 hae
757 | 4. xii | 156-0 ro) |) x/r 10 | 320-136 | 497} 1/1 497 507 | 46-1
759 5. Xii | I19-0 | 107 1/1 107 | 260-100 | 380] 1/1 380 487 | 39°5
760 6. xii | 178-0 II 1/1 II | 260-140 41 1/1 41 52 | 15°05
Eastern Scotia Sea, Dec. 1931
761 8. xii | 151-0 | 108 | 1/1 108 | 290-140 | 156| 1/1 156 264 | 43°4
763 8. xii | 124-0 | 123 1/5 615 | 280-100 Shey || sufi 70 685 | 21-4
765 | 9.x} 104-0 | 393 | 1/8 3,144 | 206-114 | 473] 1/1 473 | 3,617 | 57°8
766 | 10. xii] 102-0 | 145 | 1/4 580 | 230-110 | 100] 1/1 100 680 | 11-7
G7. || Lite oxi — —- _ — 270-118 75 1/10 750 — (25:6)
768 | 11. xii] 119-0 | 177 | 1/10 1,770 | 248-120 | 357] 1/2 714 2,484 | 36:0
769 | 12. xii] 144-0 | 465 | 1/10] 4,650 | 342-150 | 205] 1/5 1,025 5,675 | 43°8
RHINCALANUS GIGAS 371
Table III a (cont.)
Upper net Lower net
% of R. gigas in
total Copepoda
Position of Ant-
arctic convergence
examined
Fraction
examined
Estimated
Number
examined
Fraction
examined
Estimated
total
Total catch
|
South Georgia area, Dec. 1931
1/1 250-100 | IoI5 1/1
1/50 288-112 | 128| 1/5
1/5 256-170 | 651 1/5
1/50 | 8,200 | 252-102 | 169] 1/4
nye | 193 | 280-140 | 228| 1/4
1/Io | 790 | 202-133 | 259] 1/2
| 1/8 | 5,304 | 280-100 | 355| 1/4
South Atlantic, Jan. 1932
1/1 310-120 | 202| 1/1
1/r | 248-102 | 489| 1/4
1/1 250-122 206 | 1/1
_— 242-116 | 213 1/1
1/r | 334-130 | 233 1/I
1/1 210-128 | 323 1/2
1/10 6,520 | 320- 70 1/10
1/32 | 18,048 | 308-130 1/4
Weddell Sea, Jan.
| 1/4 320 | 290-104 | 1/5
1/2 74 | 216-144 1/2
1/5 20 | 264— 84 ee ah}
1/2 250-100 1/1
1/5 196-104 1/1
1/10 304-130 1/I
1/20 = =
1/10 318-102 | 1/1
1/4 | 340-100 | 1/5
1/1 314-188 1/1
1/10 40 | 256— 80 1/1
1/4 28 | 260-162 1/1
Weddell Sea and Eastern Scotia Sea, Jan.
1/1 = =
I 1/1 I ——
I 1/2 2 —
164 | 1/4 656 | 244-130
46 | 1/10 460 | 312-119 |
20 1/10 300-104
44 | 1/1 a i. al
L725 425 | 310-100 | 27
Falkland Islands to South Georgia,
Ga || iG 125 | 250-100 | 22
19 | 1/4 76 | 270- 84 | 177
391 | 1/20 7,820 | 256-140 | 550
149 | 1/50 | 7,450 250-100 | 222
|
372 : DISCOVERY REPORTS
Table III 6. Horizontal distribution of Rhincalanus gigas
Falkland Sector, 1932-3
Upper net Lower net
% of R. gigas in
total Copepoda
Position of Ant-
arctic convergence
Estimated
examined
Estimated
Total catch
total
Number
examined
Fraction
examined
examined
Fraction
|
Falkland Islands to Magellan Straits, Oct. 1932
I 1| — — —
i)
un
al
estern Drake Passage, Oct. 1932
230* 300- 80 | 296* | 1/4 1,184
119 240-100 | 292 | 1/1 292
16 290-110 | 153 1/1 153
20 244-114 | 177 | 1/2 354
464 224— 74 | 384 | 1/10 | 3,840
129 276-100 | 552 1/2 1,104
270-110 | 542 1/5 2,710
270— 90 T4305) 0/ 0 || 143
320-120 40 | 1/1 | 40
Ny NYNNNNNDN
ORO RCO STON CAE ERGY
Vi Mi ie i se
w
fe}
rake Passage) and Bransfield Strait, Oct.—-Nov.
= 350- 90 700) 0/3 76
4
w
©)
w
2)
48
20 | 300-110 1/2
533 | 230-766 | 398 | 1/1
I — = —
w
i
320-120 33 1/1
300-100 6 1/1
300-152 — 1/I
1 | 300-120 | 31 1/1
rn Drake Passage and South Atlantic, Nov.
| 1/1 I oo —
1/1 — 314-140 2
1/1 = — —
1/8 5,040 | 350-120 | 257
| 1/20 | 16,900 | 330-150 | 1135
| 1/20 | 5,420 | 320-110 | 272
South Atlantic, Nov. 1932
1/20 5,580 | 315-150 | 186
1/4 | 4,644 | 318-130 | 395
1/10 9,390 | 400-160 | 329 |
Western Scotia Sea and South Atlantic
363 | 1/10 | 3,630 | 300-125 | 474
323 1/20 6,460 | 300-150 | 105
277 | 1/8 2,216 | 370-104 | 221
307 1/ 2,156 | 270-100 | 124
82t | 1/1 82 — =
8 | 1/1 8 | 274-116 13
* Includes a few R. nasutus. + Of these the majority appeared dead.
RHINCALANUS GIGAS 373
Table III 6 (cont.)
Upper net Lower net
total Copepoda
arctic convergence
Number
examined
Fraction
examined
Estimated
Number
examined
examined
Estimated
Total catch
Fraction
| °% of R. gigas in
Position of Ant-
[ < ml
Scotia Sea and South Atlantic (east of South Georgia), Nov.—Dec. 1932
151-0 43 215 | 375—-I10 |
84-0 21 /: 84 | 250-100
117-0 ay / | 151 296-100 |
I0oo-0 | «10 ‘to | 100 | 256-100 |
84-0 | 121 / 605 | 230- 86
119-0 | 71 l4 | 284 | 340-140
103-0 | 146 4. | 584 | 295-104
133-0 | 107 856 | 340-100
98-0 | 142 / 1,420 | 250—- 90
100-0 | 339 | | 2,712 | 340-150
South Georgia, Dec. 1932
128-0 | 271 | 1/8 | 2,168 | 334-114 | 132
94-0 | 299 | 1/20 | 276-105 | 338
117-0 | 334 | 1/4 |
IIO-O | 403 /8 | 270-100 | 303
Scotia Sea, Dec. 1932—Jan. 1933
125-0 | 546 | 1/10 | 5,460 | 250-100 | 227 | 1/2
146-0 | 456 | 1/4 | 1,824 | 250-125 | 399 | 1/2
/
100-0 A | syfe | 2 | 260-100 Ge}, |) auf
Bransfield Strait, Jan.—Feb. 1933
TI9Q-o | lexfa 1] 1 | 280-124 AT ey 2
153-0 | = 250-100 27 I
134-0 | | 1/ = 290-100 22a et/|
135-0 | 2
Drake Passage, Feb. 1933
IIg—-o / — 315-130 | 144
IIO-O | | 810 | 270-115 | 514
I1g-o | | 1,040 | 320-120 | 344
100-0 | {x | 12 | 330-100 34
‘South Atlantic, Feb. 1933
70-0 | fixe | IQO-I15 86 |
102-0 250-100 | 320
97-0 290-100 1gI
100-0 | I, 5 260— 90 | 209
100-0 | / 250-106 | 275
Weddell Sea, March 1933
132-0 | 1/Zo | 335-100 55
104-0 310-110 20
93-0 260-110
119-0 f 340-100
104-0 | 290-110
117-0 } 330-100
gI-o 270-100
115-0 { : =
117-0 | s/f 365-140 15 |
South Atlantic, March 1933
es | Peta etn de ree Cc cee et
H
gI-o | | x/ 221 | 340-150 | 153 | 1/4
D XIII 13
374 ; DISCOVERY REPORTS
Table III c. Horizontal distribution of Rhincalanus gigas
Circumpolar Cruise, February—October, 1932
Lower net
% of R. gigas in
total Copepoda
Position of Ant-
arctic convergence
Number
examined
Fraction
examined
Estimated
Number
examined
Total catch
Fraction
| examined
|
South Georgia to Cape Town, Feb.—Mar.
| axa | II
| 1/ 250-100 | 210 1/1
| 250-100 zy || efit
250-100 — 1/5
250-100 6 | x/z
Cape Town to Enderby Land, April 1932
1/4 — 270-166 7 1/Io | 70
| 1/I _ 210-125 adhe || I
1/4. 228 254-110 | 1/1 155
| 1/2 220 320-190 | 1/1 514
| 1/5 390 | 370-155 1/10 | 720
1/4 | 448 190-108 | | 466
hee | 2 248- 98 |
ye 12 280-154
|
Enderby Land to Fremantle, April-May,
224-120 | 209 | 1/1
262-140 | 850 | 1/1
264-130 | 351 1/I
210-140 | 708 1/1
300-100 183 1/4
254-110 | 182 1/1
220- 98 | 299 1/4
2oo—- 82 | 161 | 1/1
290-150?| 23 | 1/1
284-110 | 48 | 1/1
330-150 | Py | aes
He He OH Oe OH Oe OS
—
wn
Fremantle to ice edge, May 1932
2I0— 90 | | x/t
270- 90 1/I
280-120 9 1/1
302-100 | 1/1
113
533 235-115 |
Ice edge to Melbourne, May—June 1932
| 83
sue 260-— 90 248
| sofas 290- Oe | 80 1/1 | 80
248 1/1
ex | 260- eo. 83 1/I
|
RHINCALANUS GIGAS 375
Table III ¢ (cont.)
Lower net
of R. gigas
in total Copepoda
arctic convergence
examined
Estimated
Total catch
examined
Estimated
examined
Fraction
examined
Fraction
5
/O
Position of Ant-
elbourne to ice edge, June
1/1 370-140 55
1/1 330-130 | 123
1/1 320-128 5
1/1 386-142 | 42
—_— 290-110 | 24
Ice edge to New Zealand, June
1/1 I 310-110 | 2
1/1 —_ 306-130 25
1/1 —_— 320-100 II
South Pacific Ocean, Aug.—Oct.
1/1 255— 80 |
1/1 310-132 |
1/1 325-144
1/1 320-100
1/1 320-128
1/1 380-110
1/I 340-120
1/1 300-128
t/t | 270-120
1/1 314-114
1/1 290-104
1/1 190— 84 |
1/1 318-140 |
1/10 290-108 |
HOR BR HON
376 ; DISCOVERY REPORTS
Table IV a. Rhincalanus gigas, percentage of total catch taken in upper and lower 1-m.
nets in the Falkland Sector during seasons 1931-2 and 1932-3 (excluding stations in
Weddell Sea water) and in the Indian Ocean and Australian Sectors in April and
May 1932
Where the combined catch in both nets amounts to less than 250 individuals the figures are placed in brackets.
Results shown diagrammatically in Fig. 12.
%
November 1931 February 1932 December 1932 (cont.)
Gas 358 7 . ii 92°0 : 30. xii] 9274 7:6
18. xi 85°6 ii 30°04 : 31. xii| 69:6 30°4
18. xi 88-2 il 93°4 A
19.xi | 15°8 . . ii 87:03 ; February 1933
20. Xi 96'1 ii
xd 72°3
Ext 28-4
53 65°4
55.1 27°54
. xi 30°3
axa 20°2
. xi 75°1
peat rerio
i| 47:6
348
= (100)
28-3 Gitta]
43°0 5770
76°7 23°3
= 100
93°5 6:5
Tigo)
October 1932
28'9
29°5
553
10°8
10°46 ii | 868
3°4
14 | 5 April 1932
ARK KK MK
mber 1932
i 4°7
57°2
66-2
75°3
65°8
88-25
85°5
851
88:5
98-4
90°5
95°2
mber 1931
ay 1932
(22°3)
mber 1932 —
51°8 : : go'8
78:6 : . (2:0)
80°3
81°5 :
72-7 ; : 2
ne 1932
RHINCALANUS GIGAS 377
Table IV 6. Rhincalanus gigas, percentage of total catch taken in upper and lower 1-m.
nets in Weddell Sea water during the seasons 1931-2 and 1932-3
Where the combined catch in both nets amounts to less than 250 individuals the figures are placed in brackets.
Results shown diagrammatically in Fig. 13.
Upper | Lower | Upper | Lower
| Date net | net 2 | net net
o/ o/ oO o/
oO /O fe} /O
|
mber 1931 January 1932 (cont.) November 1932 (cont.)
(21°1) 13.1 3:8 96:2 29. xi | (88:4) (11°6)
40°9 : 13.1 (25-2) (74:8)
(63-7) }r4.i| (568) | (43-2) eee amee
86-9 14.i| (65:1) | (34:9) 31.1 (1-2) | (98-8)
85°3 16.1 84°7 mS ee February 1933
713 28°7 7a (3:6) | (96-4) Bt eae Bae
17°5 82°5 18.1 (18-25) | (81-75) i
i
i
i
i
i
60°4 39°6 19. (13°7) (86:3) March 1933
23. 96°7 3°3
January 1932 27. 99°8 o-2
i 2 2 58-9 4I‘l
(2"9) 28. 61-15 38°85
. iil 31-3 «|:« 68-7,
iii | (13:8) | (86:2)
= 100
il | 563 43°7
il | (64-7) (3573)
ili 581 41°9
ili 68-01 31°99
-lii | (81-2) (18-8)
ili
November 1932
25. xi | (90°7) (9°3)
27.xi | (9774) (2:6)
HOO AAEY ND
nl
Table V a. Rhincalanus gigas, adults. Percentage of males and females
Falkland Sector, 1931-2
Where the numbers are too small to give reliable percentages the figures are placed in brackets.
Upper net Lower net Total Upper net Lower net Total
of o/ o/ / oe
St. | Date a i e St. | Date i re
T
? 3 2 3 2 3 2 3 ? 3 2 3
1931 1931
725 | 17-xi | 95°24 4°76 | 100 = 97°6 2°4 779 | 19. Xii | 100 — || 94:5 | 5:5 972 2°75
726 | 18. xi | 100 — | 100 — | 100 — 780 | 20. xii | 100 — 98:05) 1°95 | 99°03) 9°97
9727 |18.xi | 98-4 1°55 | 100 _- 99°2 | 077] 788] 21. xii| 99°74 06 87°3 12°7 93°3 6°7
729 | 19. Xi 98-04 1'96| 96:0 | 4°0 97°02 | 2:98 |
731 | 20. x1 | 100 —_ 99°2 0°76 | 99°6 o-4 1932 |
Ofek} || Durabal || Cy 28 87:0 13'0 g2'1 79 795 | 6.1 100 — 100 = 100 —
735 | 22.xi | 98°5 1°5 | 986 14 | 98:5 1'5 | 796| 7.i | 100 -- 99°6 o4 | 99°8 0:20
737 | 23.X1 | 100 a 93°03 6:97 | 96°5 355 798| 8.1 100 = 100 = 100 ——
739 | 24. xi | I00 96°4 3°6 98:2 18 802 | 10.1 100 = 90'8 972 95°4 46
741 | 25.xi | 98-6 24 | 96:2 3°75 | 96:9 3:1 804 | 11. i 96:0 40 | 96-7 3°3 | 963 3°7
743 | 26. xi | 100 tco.)—CU || 100 = 806 | 12. i 100 100 = 100 =
745 | 28. xi | 100 — 913 8-7 95°6 43 807 | 13. — | — | (95-8) | (42) | (958) | G2)
746 | 28. xi | 100 — 94/0 6:02 | 97:0 30 oe used — i) ||) 919 81 Noy —.
8 | 29. xi 8-2 1°76 I'l 8: 09 | 14.1 100 — | 100 a =
Cal : Ales ePiaeate es 810 i i | (87-5) | (12°5) | (955) | (45) | (ores) | (8:5)
751 | 1.xii| 99:3 0:69 | 98:97| 1:03| 99°1 0:86} 812) 16.i |(100) —_ (g1'2) | (9°6) | (95-2) | (4°8)
753 | 2.xii| 90:0 roo | 943 | 5:7 | 92:2 | 7:8 815 | 17-1 — = (7079) | (29°1) | (85°5) | (14'5)
755 | 3.xXli| 100 — 9911 | 089] 99°6 o'4 816 | 18.i |(100) — \(100) — __ |(100) =
757| 4.xii| 100 = 97°04) 2°96| 98'5 1s | 817|19.i |(100) (soro) | (50°0) | (75°) | (25°0)
759| 5.xii| 100 = 99°5 0°48 | 99°76| o24| 822} 23.1 92°96 | 7:04 | (86-7) | (13°3) | 89°8 10°17
761 | 8. xii | 100 —_ 95°1 49 Ora || 25 823 | 27-1 100 = = 100 are
763 | 8.xii| (97-7) | (2:3) | (59:3) | (40°7) | (78°5) | (2175) | 824 27-1 | 100 = Ta ng Fee pee oa
765 | 9.xii| 97°7 2°73 | 46-9 | 53:1 72:3 | 27:7 | 825|28.i | 100 — | (91-7) | (83) | 95°9 ae
766 | 10. xii | 95°9 41 67°7 | 32°3 81:8 | ee ae 7 |
68 | 11. xii 6:0 ore} 8- 61° 67°2 B2n 28 | 17. ii = = = == Shas
Bs 16. Xii ae att Bae ae 96°75 3°25 | 829 | 18. ii = = (33°4) | (66:6) | (33°4) | (66°6)
775 | 16. xii | 97°4 26 | 50:8 | 49:2 | 74:1 25°9 | 830|19.ii | 97°6 24 | 908 92 | 94:2 58
776 | 17. xii | 100 — 95°4 4°4 978 | 2-2 831 |20.ii | — | — ——) i || =F
778 | 18. xii | 100 — 83:2 | 16:8 | 916 | 8-4 834)| 23.11 ||) — a 92°0 8-0 920 8-0
| | LU
378
DISCOVERY REPORTS
Table V 6. Rhincalanus gigas, adults. Percentage of males and females
Where the numbers are too small to give reliable percentages the figures are placed in brackets.
Upper net
o/
/O
Lower net
oF
/0
Falkland Sector, 1932-3
Lower net
0/
/O
Sy
Table Vc. Rhincalanus gigas, adults. Percentage of males and females
Circumpolar Cruise, April—Fune 1932
Where the numbers are too small to give reliable percentages the figures are placed in brackets.
Lower net
%
Upper net
0
oO
Lower net
o/
/0
3
RHINCALANUS GIGAS 379
Table VI a. Rhincalanus gigas. Percentage of nauplii (N) and of copepodite stages (t-v1)
Drake Passage and South Atlantic Ocean, November 1931 (Fig. 19)
Upper net Lower net
N | i
|
Western Drake Passage (Magellan Straits to ice edge)
— | 80-0 | | —
3°6 | 56:0 .
2°5 | 33°6
42°9 | 32°6
40°7 | 46°5
35°2 | 49°1
Ice edge (Southern Drake Passa
0:96 | r0°9 | 46-3 | 41°74] —
Av || 202.9 45;0) 2728) 1
42 |17°03|54°5 |23°5 | —
C7 ler) Gyre lee || —
Eastern Drake Passage and South
we | eheey eee |) ad
370 | 29°70 | 585 | 9°5
3°7. | 40°0 | 50-0 6-05
18 | 37°3 | 45°7 | 15:26
O5 | 10-7 | §2°r | 36:5
Table VI 6. Rhincalanus gigas. Percentage of nauplii (N) and of copepodite stages (1-v1)
Scotia Sea and South Georgia, December 1931 (Fig. 20)
When percentages are based on less than roo specimens the figures are bracketed.
ee yee Upper net Lower net
1931 be ms ; :
N | i | ii ili iv v vi N i il ili iv Vv vi
Western Scotia Sea and South Atlantic
751| 1.xii] — | — | — | — |1073 | 52:1 | 3766) — — | — — |109 | 42:8 | 46-3
753| 2.xii} — — | — — | 8-86 | 80-72 | 10°44] — —_— — | o12| 31°5 | 60°7 6:7
Aes) Se Xi || — — — — |13°0 | 53°8 | 32:4 = = = 2°8 | 20:2 | 48:2 | 34:0
sai || Zoestl ||) — = | = _— (10) || (80) | (10) = = | — 12) 38:2) Sars \eaee
759) \(5-0-Xi || — = —= || ts eres oO | eral) = —= || = || Oe) ey I form || Gene
Eastern Scotia Sea
761 | 7.xii] — — — 2°7 | 23°0 2°8 | 21-3 —_— — | — | — | 204 | 35:2 | 52:0
763| 8. xii} — — — | — 3:2 | 26:8 | 69-1 —_ —_ — | 28°5 | 32°8 | 38:5
765 | 9. xii} -— — | — — | 2:8 | 24:1 | 7370 — — — | 063] 7:4 | 46:8 | 44:9
766 | 10. xii} — — — —_ 3°38 | 27°6 | 66°8 — — | — | — 970 | 23°0 | 68-0
768|11.xii} — | — | — | 1x | — | 14°65 | 84:2 —_— — | — — | 0:28] 28-9 | 70°9
South Georgia
774| 16. xii | — | | asx 1166:3) 32:6 — — = | — | 2 69 | 49°9 | 48°35
sre rGexu | — | — | o-25 | o5 | 22 | 533 |'42:5 | — | = | =} = j/are jigg0° [492
776|17. xii} — — — 3:4 | 46:8 | 27-2 | 22:4 — — —_— — | 184 | 34:8 | 44:6
788 | 21. xii] — — — o-15| 2°65] 50°0 | 47°05] — — — — 2°26 | 37°4 | 60°0
380 DISCOVERY REPORTS
Table VI c. Rhincalanus gigas. Percentage of nauplii (N) and of copepodite stages (t-v1)
South Atlantic and Weddell Sea, December 1931—fanuary 1932 (Figs. 21-23)
Gaui aats Upper net Lower net
1931-2
N i il ili iv Vv Vi N i il ill iv v vi
Bellingshausen Sea current :
Capes || keds Satll| | 712} 6-1 | 13°4 43 res} || G¥eokts || eX — — = — 6-6 | 3071 | 63:2
Gey || Yai! _ — | 13:0 | 80-1 53} 1°36| o2r| — — = 74 |25°6 | 15°5 | 49°50
8021 | 10.1 — — | — | 34:2 | 48-4 4:8 | 12-4 — = 6222127620270 _ 092
803" | 10.1 = = || Shei || See) peer? || eee] ag |p = = — lakh eer | gee || es
Weddell Sea
770% | 19. Xil | — — —_— I'5 wo egiten 59:6 — = — — |11-4 | 28-9 | 64:0
FOV |) (aa Numbers insignificant —_ — — 170 | 16°8 | 46°5 | 35-1
798° | 8.1 99 29 = = = Ig | 24°0 | 55:9 | 18:3
806° | 12.1 9» * = = = Ig | 30°9 | 53°7 | 13°4
808? | 13.1 on eS = — — 0°78 | 22:2 | 48:4 | 28-4
780° ||| 1; Xii\\|| —— = | = —_ 2h 22S |C7 EO — — = — zee) | at} || Ghsi7/
8048 | 11.1 = — — 6:25113275) |) 30:0) 3255 _ = = 1:7) | U5 900) || 3023) 5254!
807° | 13.1 Numbers insignificant — — — — | 18-0 | 34:0 | 48:0
8094 | 14. i D = = = 105 | 11-6 | 34°7 | 52°6
8107 | 14.1 55 *3 — -— — 8:5 6°38 | 10:2 | 74:6
8124 | 16.1 = = = | eRe |G ReISN| | ey Gs = = == 1°75 | 5°25 | 1°75 \| 9x15
816° | 18.1 Numbers insignificant — — = 1-7 | 64:2 | 34:0 —
817° | 19. i 0 ss — — — |17:0 | 65-3 | 16-4 I°1Z
822° | 23.1 —_ —_— — —_ 06 | 12:9 | 86:6 Numbers insignificant
823° 27-1 ae =a =, pe ar: 8-6 913 ” ”
S24 \o751 _ —_ —_ 0:29 | 6:17 | 82°6 | 10-2 — — = — ey || ieee) || Rise
825 | 28.1 = Sete 72007074 | ese || == || 37 5%). |) Feb peek | zee
1 Average temp., 0-100 m., I-3:0° C.
3 Average temp., 0-100 m., — I:0-0° C.
5 Average temp., 0-100 m., < —1:0° C. East wind drift current.
Average temp., 0-100 m., o-1'0° C.
Average temp., o-I00 m., < —1'0° C.
Average temp., o-100 m., < —1°5°C.
oF
Table VI d. Rhincalanus gigas. Percentage of nauplii (N) and of copepodite stages (i-v1)
Falkland Islands to South Georgia, mid-February 1932 (Fig. 24)
When percentages are based on less than 100 specimens the figures are bracketed.
Lower net
(21-6) | (78-4) rs insignificant
Numbers insignificant ° 12-3)
7°4 | 16:6 | 26:82 : = P 28-7
4:02 | 55°7 | 35°5 ; ; : 4 | 5570
= || 73 ere = "76 | 15°7
RHINCALANUS GIGAS 381
Table VI e. Rhincalanus gigas. Percentage of nauplii (N) and of copepodite stages (i-vt)
South Indian Ocean and Australian Sector. Winter months, April, May, Fune 1932 (Fig. 25)
Upper net Lower net
Cape Town to Enderby Land
17°5 | 35:r | 24:5 | 228 | —
42°7 | 40:0 | 13°6 18 =
wee) | 2Oi5 5325) 2529 Sats 4
Enderby Land to Fremantle
Numbers insignificant —
Ice edge to Melbourne
| tor | 58:9 |206 | — | — | — —
Numbers insignificant
Melbourne to ice edge
Numbers insignificant | — |
Table VI f. Rhincalanus gigas. Percentage of nauplii (N) and of copepodite stages (i-vt)
Drake Passage, October-mid-November 1932 (Fig. 26)
When percentages are based on less than 100 specimens the figures are bracketed.
Jpper net Lower net
|
Western Drake Passage (Magellan Straits to ice edge)
— | (48-0) | (16-0) (Gxe))|| — | 18-9 | 24°4
0°84) 11-6 | 44°5 | 42°04 | 154 | 17-1
4°5 | 38:6 | 20:9 | 36:5 | . sanicey || ney
5°4 | 54:2 | 1974 | 20°9 ¢ 22°0 | 16:4
| 144 | 319 | 53°6 "7 | 18:4 | 39°8
None ‘I | 30:0 | 34°8
Southern Drake Passage
Numbers insignificant | — | : 23°9 | 36°5
Eastern Drake Passage
8:5 | 53°7 | 37°4 = | 14°8 | 50°9
43 | 45°7 | 49'8 == | 7 | 19°6 | 46-4
382 DISCOVERY REPORTS
Table VI g. Rhincalanus gigas. Percentage of nauplii (N) and of copepodite stages (1-v1)
Scotia Sea and South Atlantic, mid-November—December 1932 (Fig. 27)
Upper net Lower net
N i ii ili iv Vv vi
South Atlantic
ro21|13.xi | — —_ _— — |14°6 | 69:8 |15-4 | — — — — As7 | (OO%tm 20:0
Western Scotia Sea
HEIs) || WO S| || —— — | — 0°32| 6:8 | 37:8 | 35-9 = os an Sar es net ere
1031 | 20. xi —_ — —_ Cro) Ge || eee | ZAR || — — — og | 16:73 | 8273
1033 | 21. Xi — = — 03 4:17 | 19:2 | 76:17] — = — —_— 4:0 | 218 | 74°1
Scotia Sea and South Atlantic (east of South Georgia)
1048 | 30. xi = = | = — 5°6 | 28-1 | 66-2 — — —_ — —- — =
1050| 1.xii}| — — | — 0°68 | 89 | 29°5 | 69:08) alt ae a — | — — —
1052| 2.xii} — — | — — — | 486 | 51-4 — | — — — | 2:4 | 23:8 | 61-9
1054 | 3.x) — = — B55) ||) Ory | 26°74 | 69-0 — | — Tez 51 0°61 | 27°8 | 65-1
LO50)| 4X11 || — —_ — 5-6 | 1°47| 185 | 74:28] — — — — — —
South Georgia
1063 | 11. xii] — — — | — — | 19:91 | 80:06] — —- | — — 2°05 3235) | OSs x
1066 | 12. xii | — — —_ — — |a2r1 | 78-9 — —_ — o'9 9:2 | 32:0 | 68-6
HC /s} || 78S Jo aa || = = = 03. | 20°r | 79°5 == — — = = == =
1076 | 13. xii | — —_ = _— 5:0 | 22:0 | 77°4 — — _— = 235 | 221 | 75:2
Scotia Sea
1083 | 30. xii | — = = — | — | 24:3 | 75-6 — —_ _ —_ — | 32-1 | 67:8
LOS Ga eg re scl ec—— ||—— -= om | == | 2ep3. |) Soy — — | — — — | 208 | 79:2
| | | |
Table VI h. Rhincalanus gigas. Percentage of nauplii (N) and of copepodite stages (t-v1)
Drake Passage and South Atlantic, February 1933 (Fig. 28)
Upper net Lower net
Passage
= 45°6 | 123
0°76 | 15 0°38 | 62°3. | 34°96
South Atlantic
0:10) 12-3) | 37:0) 13877
Numbers insignificant
——) |a-3)) 18-7,
— | 40:0 | 44:0
03 | 39°4 | 55°6
RHINCALANUS GIGAS 383
Table VIz. Rhincalanus gigas. Percentage of nauplii (N) and of copepodite stages (i-vt)
Weddell Sea and South Atlantic, March 1933 (Fig. 29)
St | Dat Upper net Lower net
‘ ate
| 1933
| N 1 ul ll iv Vv vi N i il ii iv Vv vi
| | |
Weddell Sea
TsO) |) 2. iit —_ — | — | 20:0 | 50:0 | 20:0 | 10°0 — = ||| = 26-45 | 38:20 ir2z-6Mia2-7,
1142) 4. iii None -—— — 0-8 | 19:04! 77-0 g2 =
1144] 5. iii —_— — | 4:3 | 43:0 | 30°r 17-2 | 4°3 —_— — | — 7723 2OP2en eS Os2 aa eige
1148 | 9. ili = ==) | == 34708 52208 | 1520 — — — 2-1 | 228m || 62-0) eres
I150 | 10. ili —_ — — 42:40 O72 a er S Numbers insignificant
1152 | 10. ili —_ = | = — | 26:0 | 50:0 | 23°9 oa = — |}|—}]-—f]— —_
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