A FLORISTIC STUDY OF THE ATTACHED ALGAE
OF LAKE MIZE, FLORIDA
By
HELEN DAVIS BROWN
A DISSERTATION PRESENTED TO THE GRADUATE
COUNCIL OF THE UNIVERSITY OF FLORIDA IN PARTIAL
FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA
1972
Copyright by
Helen Davis Brown
1972
ACKNOWLEDGEMENTS
For his continued encouragement and guidance, the
author wishes to thank Dr. Dana G. Griffin, III, Chairman
of the Supervisory Committee. The writer would also like
to extend her sincere thanks to Dr. Richard Smith and
Dr. Frank Nordlie for generously providing both advice
and special equipment for certain portions of the study.
Thanks are also due Dr. Leland Shanor , Dr. Henry Aldrich,
Dr. James Kimbrough, and Dr. Frank Nordlie for critically
studying this manuscript and for providing valuable
suggestions for its improvement.
The author would also like to express gratitude
to Dr. Clark Cross for his help in various ways during
the study and to A. Baker, Dr. Alan Brook, and Marilyn
Lash for their assistance in devising some of the equip-
ment and procedures used in this investigation.
Acknowledgements and thanks are also accorded the
following authorities, each of whom provided identifications
of certain species critical to the study: Dr. William
Daily, Dr. L. A. Whitford, Dr. Robert Bland, Dr. Hannah
Croasdale, Dr. Alan Brook, and Dr. James Lackey.
The use of Lake Mize, Florida, as a study area was
graciously provided by Dr. John Gray, Chairman, Department
111
of Forestry, and by Mr. Don Post, Director, Austin Gary
Memorial Forest. The facilities at Elk Lake, Minnesota,
were made available by the Itasca Biology Station, Univer-
sity of Minnesota (Dr. William Marshall, Director).
Financial assistance for various portions of this
study was provided by an assistantship from the Botany
Department, University of Florida; by a Graduate School
Fellowship from the University of Florida; and by NSF grant
GB 3390 (Itasca Biology Station) .
Finally, the writer would like to thank her parents,
family, and friends for their encouragement and support
during the course of this study.
XV
TABLE OF CONTENTS
Page
ACKNOWLEDGEMENTS iii
LIST OF TABLES ix
LIST OF FIGURES XV
ABSTRACT xviii
I . INTRODUCTION 1
II . LITERATURE REVIEW 3
Terminology 3
Growth Forms of Attached Algae 5
Substrates Used in Studying
Attached Algae 5
Vertical Zones of Periphyton
Distribution 9
Suocessional Tendencies in
the Periphyton 10
III . DESCRIPTION OF THE STUDY AREAS 14
Lake Mize 14
Location 14
Morphometry 15
Chemistry and Physios 15
Recent History of Lake Mize 23
Aquatic Macrophytes of Lake Mize 24
Surrounding Vegetation of Lake Mize 25
Elk Lake 27
IV. MATERIALS AND METHODS 30
General Sampling 30
Use of Sub strates 30
Littoral Area Methods 31
Limnetic Area Methods 34
Collecting Procedures 36
Species Composition Method 36
Physical Measurements 39
V
TABLE OF CONTENTS — Continued
Page
V. OBSERVATIONS AND RESULTS 4 0
Limitations of the Study 40
Lake Mize Studies 42
Colonization of Substrates by Algae 42
Spatial Variation in the Periphyton
in Lake Mize 46
Seasonal Variation in the
Periphyton in Lake Mize 49
Attached Algae Present in the
Limnetic Area of Lake Mize,
Winter^ 1968-1969 50
Vertical Distribution of Attached
Algae on Glass Slides, December ,
1968, to February, 1969 51
Variation in Algal Flora on Glass
Slides with Time, Winter,
1968-1969 59
Attached Algae Present in the
Limnetic Area of Lake Mize,
August to September, 1969 63
Vertical Distribution of Attached
Algae and Other Periphyton on
Glass Slides, August to
September, 1969 64
Changes in the Algal Flora on
Glass Slides with Time,
August to September, 1969 80
Adaptive Algal Forms Present ,
August to September, 1969 84
Attached Algae of the Littoral
Area, August, 1969 85
Planktonic Algae, August to
September, 1969 88
Attached Algae Present in the
Limnetic Area of Lake Mize,
August, 1970 88
Vertical Distribution of Attached
Algae and Other Periphyton on
Glass Slides, August, 1970 89
Variations with Time in the Algal
Flora Present on Limnetic Area
Slides, August, 1970 99
Vi
TABLE OF CONTENTS — Continued
Page
Vertical Distribution Patterns
of Attached Algae and Other
Periphyton on Websteria
submersa^ August^ 1970 100
Variations with Time in the
Algal Flora Present on
Websteria submersa,
August, 1970 116
Comparison: Algal Flora of Glass
Slides and of Websteria
submersa, August, 1970 117
Planktonic Algae, August 13, 1970 123
Attached Algae of the Littoral
Area, August, 1970 124
Attached Algae on Glass and Plastic
Slides, Littoral Area,
August, 1970 127
Other Littoral Studies, May, 1969;
July, 1969; April, 1971; July,
1971; and September, 1971 138
Planktonic Algae, September , 1971 149
Elk Lake Studies 150
Vertical Patterns of Attached Algae
and Other Periphyton on Glass
Slides in Elk Lake, July to
August, 1967 151
Variation with Time in the Algal
Flora Present on Glass Slides,
Elk Lake Limnetic Area,
August, 1967 158
Attached Algae of the Littoral Zone,
Elk Lake, Agusut , 1967 160
Comparison: Attached Algae of
Lake Mize, Florida, and Elk
Lake, Minnesota 161
VI. DISCUSSION 164
Losses Due to Peeling 164
Changes with Time: Colonization
and Succession 165
Influence of the Sub strate 167
Vll
TABLE OF CONTENTS — Continued
Page
Influence of Physical Factors —
Current 172
Influence of Physical Factors —
Light 173
Influence of Physical Factors —
Temperature 174
Seasonal Influences 175
VII. SUMMARY 178
APPENDIX 181
LITERATURE CITED 199
BIOGRAPHICAL SKETCH 2 04
Vlll
LIST OF TABLES
Table Page
1. Secchi Disc Measurements in Lake Mize,
October 2, 1968, to August 13, 1970 20
2. Temperature Measurements from the
Surface Waters of the Littoral
Zone of Lake Mize, August, 1968,
to August, 1970 22
3. Representative Sampling Errors as
Experienced in the Proportions and
Frequencies of Mougeotia sp. ,
Diatoms, and Algae on Replicate
Glass Slides Exposed at a Depth
of 6 Inches for 4 Weeks During
the 1968-1969 Winter Study 43
4. Dominant Algal Species Found on Glass
Slides Suspended in the Limnetic
Zone of Lake Mize for 1 Week,
December 7 to December 17, 1968 53
5. Proportions of Algal Divisions and
Attached Protozoa Present on Glass
Slides Suspended in the Limnetic
Zone of Lake Mize for 1 Week,
December 9 to December 17, 1968 54
6. Dominant Algal Species Found on Glass
Slides Suspended in the Limnetic
Area of Lake Mize for 4 Weeks,
December 17, 1968, to January 9, 1969 55
7. Proportions of Algal Divisions and
Attached Protozoa Present on Glass
Slides Suspended in the Limnetic
Zone of Lake Mize for 4 Weeks,
December 17, 1968, to January 9,
1969 56
a.x
LIST OF TABLES — Continued
Table Page
8. Number of Algal Species Present at
Various Depths on Glass Slides
Suspended in the Limnetic Area
of Lake Mize for 1 Week,
December 9 to December 17, 1968 60
9. Number of Algal Species Present at
Various Depths on Glass Slides
Suspended in the Limnetic Area
of Lake Mize for 4 Weeks,
December 17, 1968, to
January 9, 1969 61
10. Dominant Algal Species Found on Glass
Slides Suspended in the Limnetic
Area of Lake Mize, for 1 Week,
August 7 to August 14, 1969 65
11. Number of Algal Species Present at
Various Depths on Glass Slides
Suspended in the Limnetic Area
of Lake Mize for 1 Week,
August 7 to August 14, 1969 69
12. Number of Algal Species Present at
Various Depths on Glass Slides
Suspended in the Limnetic Zone
of Lake Mize for 3 Weeks,
August 7 to August 28, 1969 70
13. Number of Algal Species Present at
Various Depths on Glass Slides
Suspended in the Limnetic Zone
of Lake Mize for 6 Weeks,
August 7 to September 11, 1969 71
14. Dominant Algal Species Found on Glass
Slides Suspended in the Limnetic
Zone of Lake Mize for 3 Weeks,
August 7 to August 28, 1969 74
LIST OF TABLES — Continued
Table ^^9^
15. Dominant Algal Species Found on Glass
Slides Suspended in the Limnetic
Zone of Lake Mize for 6 Weeks,
August 7 to September 11, 1969 77
16. Proportions of Algal Divisions and
Other Groups of Organisms Present
on Glass Slides Suspended in the
Limnetic Zone of Lake Mize for
6 Weeks, August 7 to
September 11, 1969 79
17. Proportions of Algal Divisions and
Attached Protozoa Present on
Glass Slides Suspended in the
Limnetic Zone of Lake Mize for
3 Weeks, August 7 to
August 28, 1969 82
18. Proportions of Algal Divisions and
Attached Protozoans Present on
Glass Slides Suspended in the
Limnetic Zone of Lake Mize for
1 Week, August 7 to August 14, 19 69 83
19. Dominant Algal Species Present on
Glass Slides Suspended in the
Limnetic Zone of Lake Mize for
3 Weeks, July 23 to August 13, 1970 90
20. Dominant Algal Species Present on
Glass Slides Suspended in the
Limnetic Zone of Lake Mize for
4 Weeks, July 23 to August 20, 1970 94
21. Proportions of Algal Divisions and
Other Groups of Organisms Present
on Glass Slides Suspended in the
Limnetic Zone of Lake Mize for
3 Weeks, July 23 to August 13, 1970 97
XI
LIST OF TABLES — Continued
Table Page
22. Proportions of Algal Divisions and Other
Groups of Organisms Present on Glass
Slides Suspended for 4 Weeks in the
Limnetic Zone of Lake Mize, July 23
to August 20, 1970 98
23. Number of Algal Species Present at
Various Depths on Glass Slides
Suspended in the Limnetic Zone
of Lake Mize for 3 Weeks, July 23
to August 13, 1970 101
24. Number of Algal Species Present at
Various Depths on Glass Slides
Suspended in the Limnetic Area
of Lake Mize for 4 Weeks, July 23
to August 20, 1970 102
25. Number of Algal Species Present at
Various Depths on Websteria
submersa Suspended in the Limnetic
Zone of Lake Mize for 3 Weeks,
July 23 to August 13, 1970 103
26. Number of Algal Species Present at
Various Depths on Websteria
submersa Suspended in the Limnetic
Zone of Lake Mize for 4 Weeks,
July 23 to August 20, 1970 104
27. Proportions of Algal Divisions Present
on Websteria submersa Suspended in
the Limnetic Zone of Lake Mize for
3 Weeks, July 23 to August 13, 1970 108
28. Proportions of Algal Divisions and
Attached Protozoa Present on
Websteria submersa Suspended in
the Limnetic Zone of Lake Mize
for 4 Weeks, July 23 to
August 20, 1970 109
Xll
LIST OF TABLES — Continued
Table Page
29. Dominant Algal Species Found on Websteria
submersa Suspended in the Limnetic
Zone of Lake Mize for 3 Weeks, July 23
to August 13, 1970 HO
30. Dominant Algal Species Found on Websteria
submersa Suspended in the Limnetic
Zone of Lake Mize for 4 Weeks, July 23
to August 20, 1970 HI
31. Comparison of Algal Flora Present on
Vertically Positioned Glass Slides
and on the Aquatic Plant, Websteria
submersa, on August 13, 1970, after
3 Weeks' Suspension in the Limnetic
Zone of Lake Mize, Florida (VA =
Very Abundant, A = Abundant, C =
Common, I = Infrequent, and R = Rare) .... 118
32. Number of Algal Species Present on Glass
and Plastic Slides Exposed in the
Littoral Area of Lake Mize at a
Depth of 18 Inches, Collected
August 15 and 20, 1970 128
33. Frequencies of Dominant Algal Species
Present on Glass and Plastic Slides
Exposed in the Littoral Area of
Lake Mize at a Depth of 18 Inches,
Collected August 15 and 20, 1970 129
34. Attached Algae Found on Glass Slides,
Websteria submersa , and Sphagnum
maarophyllum Placed in the
Littoral Area of Lake Mize
(Station 1) , 18 Inches Below the
Surface for 4 Weeks, July 21,
August 15, 1970 132
35. Number of Algal Species Present at
Various Depths on Glass Slides
Suspended in the Limnetic Area
of Elk Lake, Minnesota, for 1 Week,
July 21 to July 28, 1967 154
Xlll
LIST OF TABLES — Continued
Table Page
36. Number of Algal Species Present at
Various Depths on Glass Slides
Suspended in the Limnetic Area
of Elk Lake, Minnesota, for 2
Weeks, July 21 to July 28, 1967 155
37. Number of Algal Species Present at
Various Depths on Glass Slides
Suspended in the Limnetic Area of
Elk Lake, Minnesota, for 3-1/2
Weeks, July 21 to August 14, 1967 156
38. Master List of the Attached Algae of
Lake Mize, Florida, and Planktonic
Species Associated with Communities
of Attached Algae, December, 1968,
to September, 1971 182
39. Master List of the Attached Algae and
Planktonic Species Associated with
Attached Algae in Elk Lake,
Minnesota, August, 1967 192
40. The Algal Flora Present on Vertically
Positioned Glass Slides Suspended
in the Limnetic Zone of Lake Mize
during January, 1969; August, 1969;
and August, 1970 (VA = Very
abundant , A = Abundant , C = Common ,
I = Infrequent, R = Rare) 194
xiv
LIST OF FIGURES
Figure Page
1. Bathymetric map of Lake Mize, showing
sampling stations 1, 2, 3, and 4.
(Courtesy of Dr. Frank Nordlie) 16
2. North-South view of Lake Mize, Florida 17
3. Light penetration in Lake Mize,
Florida (Winter) 19
4. Light penetration in Elk Lake on
August 14, 1967 28
5. Glass slide showing periphyton
present after 3 weeks' exposure
in Lake Mize (xl) 33
6. Plastic enclosure used in Lake Mize
littoral studies (xl/lO) 33
7. Areas counted, indicated by lines, on
glass slides in Lake Mize studies 37
8. Frequencies of 3 algal divisions
present on glass slides suspended
in the limnetic area of Lake Mize
for 1 week, December 9 to December 17,
1968, and for 4 weeks, December 17,
1968, to January 9, 1969 52
9. Frequencies of 3 algal division and of
the dominant algal species present
on glass slides suspended in the
limnetic area of Lake Mize for
1 Week, August 7 to August 14, 1969 67
10. Frequencies of the dominant algal species
present on glass slides suspended
in the limnetic area of Lake Mize
for 3 weeks , August 7 to
August 28, 1969 68
XV
LIST OF FIGURES — Continued
Figure Page
11. Frequencies of dominant algal species
present on glass slides suspended
in the limnetic area of Lake Mize
for 6 weeks, August 7 to
September 11, 1969 73
12. Frequencies of 3 algal divisions on
glass slides suspended in the
limnetic area of Lake Mize for
3 weeks, August 7 to August 28,
1969, and for 6 weeks, Agusut 7
to September 11, 1969 81
13. Frequencies of dominant algal species
and the major groups of attached
organisms present on glass slides
suspended in the limentic area of
Lake Mize for 3 weeks, July 23 to
August 13, 1970 92
14. Frequencies of dominant algal species
and the various groups of attached
organisms present on glass slides
suspended in the limnetic area of
Lake Mize for 4 weeks, July 23 to
August 20, 1970 93
15. Frequencies of dominant algal species
present on Websteria submersa
suspended in the limnetic area of
Lake Mize for 3 weeks, July 23 to
August 13, 1970 106
16. Frequencies of dominant algal species
present on Websteria submersa
suspended in the limnetic area of
Lake Mize for 4 weeks, July 23 to
August 20, 1970 107
17. Germlings of Bulhoohaete sp. on
Websteria submersa (x400),
Lake Mize 187
XV 1
LIST OF FIGURES — Continued
Figure ^^9^
18. Colony of Protoderma viride , a prostrate
Chlorophyte , with diatoms, Nitschia
palea and Frustulia rhomboides
(xl,400), Lake Mize 187
19. Osaillatoria tenuis filaments (xl,300).
Lake Mize 187
20. Anabaena osoillavioides (xl,000),
Lake Mize 187
21. Closterium setaaeum (x320), Lake Mize 189
22. Closterium navicula (x600), Lake Mize 189
23. Oedogonium sp., showing holdfast (x400),
Lake Mize 189
24. Branched filaments of Hapalosiphon
fontinalis (x500), Lake Mize 189
25. Portion of the attached community of
a glass slide, showing Cosmarium
regnellii Eunotia sp. , and a
filamentous Oomycete (x600) ,
Lake Mize 191
26. Frustulia rhomboides var. saxoniaa
(x750) , Lake Mize 191
27. Rhipidodendron splendidum , a
heterotrophic Chrysophyte
(X300), Lake Mize 191
28. Epithemia zebra (x400), Elk Lake 191
XVI 1
Abstract of Dissertation Presented to the Graduate Council
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy
A FLORISTIC STUDY OF THE ATTACHED
ALGAE OF LAKE MIZE, FLORIDA
By
Helen Davis Brown
August, 1972
Chairman: Dr. Dana G. Griffin, III
Major Department: Botany
A floristic survey from December, 1968, to
September, 1971, provided a record of the communities of
attached algae in Lake Mize, Florida. Counts and estimates
of organism densities were used to determine the relative
abundance of species. In all, 89 species were identified
and monitored during the study period. Both quantitatively
and qualitatively, desmids and filamentous Chlorophytes were
usually an important part of the periphyton in Lake Mize.
Several acidiophilic diatoms were abundant at certain times,
while Cyanophytes generally reached high frequencies only
during the July to September period.
In the course of the investigation, it was determined
that algal species employing particular modes of attachment
were more abundant under some conditions than others.
XVlll
Generally, tightly adhering, resupinate forms attained higher
densities on glass slides than filamentous and loosely
associated metaplanktonic species. Conversely, the epiphytic
flora of the filamentous sedge, Websteria suhmersa, contained
a large number of both strong and weak attachers. Other
broad-leafed macrophytes in the lake normally had an epi-
phytic flora composed mainly of filamentous and/or resupinate
species with somewhat fewer metaplanktonic algae than the
flora of W. submersa. However, no absolute substrate speci-
ficity could be shown for any one species or by any attaching
form. A major observation to come from this investigation
was that the attached flora varied not only with substrate
type, but that different areas of the lake supported some-
what different periphyton communities. In calmer areas of
the lake or in protected enclosures, metaplanktonic and
filamentous species were more abundant on all substrates than
in areas subjected to currents and turbulence.
When clean substrates (slides or plants) were
submerged, the pioneering attachers were usually the most
abundant resupinate and/or filamentous forms in the lake at
that time. Debris became associated with the attached algae
community for a period up to 5 weeks. The number of meta-
planktonic species increased as well as total algal frequen-
cies. In excess of 3 to 5 weeks, peeling ensued with a
subsequent loss of debris and algae, especially debris-
associated metaplanktonic forms.
XIX
Whereas the type of substrate and the amount of
current appeared to be critical in determining whether weak
attachers would be present in a given periphyton community,
light was also important in governing the floristic compo-
sition of the community in Lake Mize. Chlorophytes were
generally abundant only in the upper 6 to 18 inches of the
lake. Chrysophy tes , on the other hand, had a broader
vertical range, frequently remaining common to a depth of
30 inches on glass and 42 inches on W. submersa. In the
case of Cyanophytes, light requirements were variable. Some
species were restricted to the upper 6 to 18 inches of the
lake and others were common to a depth of 42 inches.
A comparison of the attached flora in Lake Mize,
Florida, a dystrophic lake, with that of the mesotrophic
Elk Lake, Minnesota, revealed a number of differences.
Taxonomically , the attached floras of the two lakes were
almost completely different with only three species common
to both lakes. Diatoms formed the major part of the
attached flora in Elk Lake, while Chlorophytes were
generally the dominant algal division in Lake Mize. In
Lake Mize, light was a severely limiting factor with
attached algae usually restricted to the upper 30 to 42
inches of the lake and with maximum algal frequencies
occurring in the upper 6 to 18 inches. In Elk Lake,
attached algae were common to a depth of 4 meters. Maximum
frequencies usually occurred at a depth of 3 meters.
XX
I. INTRODUCTION
The objectives of this investigation were: (1) to
analyze the composition of the attached algae communities
which appeared in Lake Mize, Florida, December, 1968, to
September, 1971; (2) to observe the successional
tendencies among the communities of attached algae in
Lake Mize; (3) to compare the attached algae communities
on glass slides with those on several aquatic macrophytes;
and (4) to compare the attached algae of Elk Lake,
Minnesota, with those of Lake Mize.
Attached algae, which are part of the periphyton,
have an important role in a lake's food web. However,
studies of the periphyton in fresh-water lakes have not
been as numerous as planktonic studies. To the author's
knowledge, no study has been made of periphyton in a
northern Florida lake. Thus, while the limno logical
features and the plankton of Lake Mize have been studied
(Harkness and Pierce, 1941; Nordlie, 1967), no prior study
has been made of its nonplanktonic algae. As a monomictic,
brown-water lake. Lake Mize holds considerable interest.
This investigation, together with those already made, will
add to our understanding of the lake as a functioning
ecosystem.
- 1 -
2 -
A pilot study of attached algae was first carried
out at Elk Lake, Minnesota, during the summer of 1967.
Elk Lake is a dimictic, raesotrophic lake. The results of
this investigation provide an interesting contrast with
those obtained from the summer studies in Lake Mize.
II. LITERATURE REVIEW
Termino logy
The term periphyton has been given several meanings
in the literature (Cooke, 1956). In this study, periphyton
is used to designate "that assemblage of organisms growing
upon free surfaces of submerged objects in water," as
defined by Young (1945). Aufwuchs , a German term, carries
much the same meaning (Sladeckova, 1962). Algal members
of the periphyton are termed phyao-periphyton (Foerster,
1963) or, attached algae (Brook, 1955; Castenholz, 1960).
Phyco-periphyton may be classified according to the
nature of the substrate upon which they occur; i.e.,
epiphytic algae, those found attached to plants and
epilithic algae, those attached to rocks and stones.
Epipelic algae are those algae associated with lake bottom
sediments (Round, 1964). The members of the metaplankton
were first considered to be the algae lying between
aquatic plants (Behre, 1956). The meaning of this term
has been broadened so that the metaplankton are considered
to be those algae loosely associated with a substrate, but
not sessile upon it (Round, 1964). In this study the
metaplankton are considered to be part of the attached
- 3 -
- 4 -
algal flora when found adhering to a substrate. It is
recognized that these forms are also part of the "plankton"
of the lake's littoral zone.
A community is considered by Odum (1959) to be
"any assemblage of populations living in a prescribed area
or physical habitat." The term oommunity is often used
to refer to various assemblages of attached algae. With
reference to the attached algae, the term denotes a group
of species found together on a certain type of substrate
(Castenholz, 1957). Within a community distinct groupings
of species called associations occur (Margalef, 1953).
Succession is the orderly process of community
change (Odum, 1959). With reference to the attached algae,
a pioneer community occurs first on a given substrate.
This pioneer community is replaced by a series of more
mature communities. In most situations, whether the
community of attached algae ever reaches what may be
properly tearmed a otimax is debatable (Blum, 1956b) . In
this study, when the terms succession or successional
tendencies are used, reference is being made simply to the
series of communities which follow each other in occupying
a given substrate in the lake.
- 5 -
Growth Forms of Attached Algae
While the raembers of the plankton are adapted to
flotation, those of the periphyton are adapted to attach-
ment on a substrate. Generally, organisms in a given
community tend to have certain growth forms. Both Round
(1964) and Fritsch (1929) report 2 main growth forms among
the attached algae: (1) species appressed to the
substrate, broad surface down; and (2) species which
produce a small attachment disc from which either a single
cell or a filament projects. Examples of the first form
include numerous diatoms and some members of the
Chaetophorales. Examples of the second form include green
filamentous algae, as Oedogonium, and diatoms attached by a
mucilaginous pedicel, as Synedra. A third growth form
is sometimes considered to occur, that of filaments within
a thick mucilage, as Nostoc (Round, 1964). A holdfast
cell or mucilage is the mode of attachment for all forms.
Substrates Used in Studying Attached Algae
In the investigation of attached algae on natural
substrates, certain difficulties are encountered.
Epilithic algae must be removed from their rocky substrate
in order to be studied microscopically. Removal of
closely adhering forms is difficult so that an extremely
- 6 -
accurate assessment of the epilithic community is usually
not possible. A method proposed by Margalef (1949a) holds
promise of partially overcoming this difficulty. His
method consists of applying a film of collodion to the
rock or stone and then peeling the film off when it dries.
To some degree, the difficulty imposed by the closely
adhering forms is also met when the attached algal flora
of aquatic macrophytes is studied. Sometimes, however,
the epidermis of the plant may be peeled, or Margalef 's
method may be used (Margalef, 1949b) . An additional
problem in studying algal succession upon aquatic
macrophytes is the problem of obtaining clean plants with-
out epiphytes. To overcome this difficulty, Prowse (1959)
grew plants in water containing silver ions. This
solution acted as an algicide and a fungicide to suppress
the growth of algal and fungal epiphytes on the plants.
Whitford (1956) studied the succession of algal epiphytes
by comparing growth on younger parts of an aquatic
raacrophyte with that on older parts.
Most investigations of attached algae have
featured the use of artificial barren surfaces. Many
different artificial barren substrates have been used:
polyethylene tape (Neal , Patten, and DePoe, 1967), plastic,
wood, slate, sheet metals, asbestos, and glass (Sladeckova,
1962) . The use of glass slides is especially widespread.
- 7 -
Sladeckova (1962) reports Kny (1884) as the first to use
this method for the study of zoospore attachment in the
laboratory. Hentschel (1916) was the first to use the
glass slide method in the qualitative and quantitative
determination of periphyton. The method has been
modified many times since Hentschel ' s work. Both smooth
and scratched glass slides have been used (Castenholz ,
1957) . The glass slide method provides the advantage of
making possible the direct microscopical observation of
attached organisms.
Several investigators have attempted to compare
the attached algal community found on glass slides with
that found on natural substrates. The species present on
glass slides appear to be almost the same as those found
on aquatic macrophytes and stones (Castenholz, 1957;
Dor, 1970). Blue-greens, however, do not colonize glass
slides as readily as natural substrates, according to
several workers (Castenholz, 1957; Sladeckova, 1962).
Numerical analyses of the species present frequently
yield different results with slides as compared to natural
substrates (Blum, 1956a; Dor, 1970).
While differences exist between the attached algal
flora of glass slides and of natural substrates, differ-
ences also exist among various forms of natural substrates.
- 8 -
Among aquatic macrophytes , Carex and Chara have few
attached epiphytes while Fontinalis and Myriophyllum are
densely populated by algal epiphytes, according to Round
(1966) . Some species of attached algae also grow much
more readily on some plants than on others (Tiffany, 1951;
Young, 1945; Prowse, 1959). Varying parts of a plant
may have different attached communities (Tiffany, 1951).
Also, while the epiphytic and epilithic communities share
many species, stones tend to have more encrusting forms
than do plants (Ruttner, 1963).
Light and ease of attachment have been theorized
to be the most important factors in the distribution of
algal epiphytes (Tiffany, 1951). Other factors also may
account for differences in the attached algal flora of
various substrates. Substrates which contain irregu-
larities seem to make attachment easier (Blum, 1956a).
Current is probably very important (Ruttner, 19 63;
Whitford, and Schumacher, 1963) . Castenholz (1957)
theorized that 1 species of CZadophora did not appear on
glass slides due to the timing of its dispersal mechanism
(zoospore production) . He also found that when slides
were exposed 6 weeks or longer, they developed encrusting
blue-green forms not usually found on slides. A time
differential may also explain some of the differences
between the species composition of plants and of stones.
- 9 -
Many aquatic plants are short-lived and are probably
populated mainly by quickly developing attached forms.
Rocks allow the colonization by forms which develop
slowly (Ruttner, 1963).
Vertioal Zones of Periphyton Distribution
Several workers have studied the vertical
distribution of periphyton in lakes or reservoirs, using
artificial substrates (Maciolek and Kennedy, 1964; Neal ,
Patten, and Depoe, 1967; Sladeckova, 1966). Maciolek and
Kennedy (1964) report that in Laurel Lake, California,
attachment on glass slides was greatest at the 5-meter
level. Diatoms were the chief attaching forms. Neal,
Patten, and DePoe (1967) used polyethylene tape as the
substrate for attachment in a polluted lake near Oak Ridge,
Tennessee. Maximum biomass development was found to take
about 2 weeks in the euphotic zone (upper 50.8 centimeters)
and longer below the euphotic zone. Biomass accumulation
was greatest in the upper 38.1 to 54.7 centimeters.
Species succession continued after maximum development of
biomass occurred. Succession began with blue-greens and
diatoms. These pioneers were succeeded by filamentous
and adhering greens.
In Polish reservoirs, Sladeckova (1966) considers
periphyton distribution to be divided into 5 zones within
the water column:
- 10 -
1. A surface zone without periphyton •
2. Zone of producers (euphotic zone) , algae
predominate ;
3. Transition zone (compensation layer) , mixture
of producers and consumers present •
4. Zone of consumers, rotifers, sessile protozoans,
etc. , predominate ;
5. Bottom zone, influenced by decomposition process
in the sediments, bacteria and large benthic
organisms present .
The above vertical periphyton distribution probably
holds true for most water bodies with sufficient depth.
At any depth, growth of periphyton is a balance between
income and loss processes. Gains occur through colonization
and primary productivity. Losses occur through respiration,
secretion, excretion, sloughing off of the periphyton film,
and grazing by consumers (Neal, Patten, and DePoe, 1967).
SuGcessi-onal Tendencies in the Periphy ton
Ecological succession in general is characterized
by a number of important features. By definition, it is
an orderly process of community development that is
reasonably predictable. Succession results from a
modification of the habitat by the organisms present in
the habitat. It is culminated by a climax community in
equilibrium with the physical environment. The physical
- 11 -
environment determines the pattern of succession, the
rate of change, and how far succession may proceed (Od\am,
1969) .
Early stages of succession have been compared to
later stages in a number of ways. Species with high rates
of reproduction and growth are more likely to survive in
early successional stages, while those species with
capabilities for competitive survival are more likely to
be present during later successional stages (Odum, 1969) .
Pioneer species are also better adjusted to indiscriminate
dispersal. During succession, there are increases in the
proportion of inert or dead matter, in biomass , in the
number of niches present, and in stratification. There is
frequently an increase in species diversity. Or,
diversity may increase and then decrease (Margalef , 1968) .
Succession is a frequent occurrence. However,
orderly unidirectional succession does not always occur in
nature. When the physical environment is extreme or
subject to large-scale fluctuations, succession either
does not continue or is pushed backward (Odum, 1969;
Margalef, 1968) .
Several studies have been made that deal with
successional tendencies in the periphyton community
(Whitford, 1956; Yount , 1956; Brook, 1954; Whitford and
Schumacher, 1963). The use of glass slides is common.
- 12 -
Colonization of bare substrates placed in a lake proceeds
rapidly. Within a few hours to a few days, bacteria
attach (Sladeckova, 1962). According to Brook (1967) the
first algal colonizers on slides in the ponds of filter
plants are generally small blue-green filaments and diatom
members of the Monoraphidae. Both of these groups usually
appear within a week. Later, large prostrate greens,
especially members of the Chaetophoraceae , appear.
Competition between closely adhering diatoms and the
prostrate greens may be severe with the outcome sometimes
influenced by grazing. In North Carolina Piedmont streams
during early spring, Whitford and Schumacher (1963) found
diatoms to form the first 2 successional stages on bare
substrates. The third stage was a gelatinous mat of the
blue-green, Phormidium subfuscum , with 2 associated
diatoms. This was followed by filamentous greens, such
as Miarospora and Stigeoolonium .
As has been pointed out previously, the actual
achievement of climax by the periphyton is questioned
by some investigators for many situations. Blum (1956b)
doubted that the climax concept should be applied to the
ephemeral algal communities of streams. However, he
also reasoned that the equivalent of a "permanent" climax
may be reached by algae in a single season. In North
Carolina streams, Whitford and Schumacher (1963) found no
- 13 -
perennial community of attached algae and questioned the
use of such terms as climax, dominant, and succession
for communities of attached algae. Within some Florida
springs, a climax community of attached algae has been
reported (Whitford, 1956; Yount , 1956). However, streams
are recognized as being stable ecosystems with physical
and chemical conditions rather uniform throughout the
year except for light (Whitford, 1956).
III. DESCRIPTION OF THE STUDY AREAS
Lake Mize
The major part of this study was carried out at
Lake Mize, Florida. Several workers have conducted
extensive investigations at Lake Mize (Harkness and
Pierce, 1941; Nordlie, 1967; Brezonik and Harper, 1969;
Brezonik, 1970). Some aspects of their studies will be
utilized in this description of Lake Mize, as well as the
observations of the writer.
Lake Mize may be characterized as a limestone
solution lake (Nordlie, 1967) . The sedimentary rock
underlying much of Florida is composed chiefly of
limestone. In a limestone area, depressions or "sinks"
sometimes develop due to the dissolving of carbonate
deposits along fault lines. These sinks may then fill
with water during subsequent Florida wet seasons and a
lake is produced (Nordlie, 1967) .
Location
Lake Mize is located in the Austin Gary Memorial
Forest, 10 miles northeast of Gainesville, Florida,
latitude 29° 44' north, longitude 82° 13' west (Harkness
and Pierce, 1941) .
- 14 -
- 15 -
Morphometry
Lake Mize has a surface area of 0.86 hectare and
a maximum depth of 25.3 meters (Nordlie, 1967). It is
generally circular in outline except for a shallow bay on
the north side of the lake (Figures 1 and 2) . Except for
the bay area, the depth of the lake increases rapidly from
the shoreline.
The littoral zone is represented by a narrow band
outlining most of the lake. When the water level is high,
a temporary stream carries the overflow into Hatchett Creek ,
The water level of Lake Mize varies considerably during
any one year as the rainfall fluctuates.
Chemistry and Physios
Lakes are generally classified as to nutrient
level, i.e., eutrophic, mestrophic, oligotrophic, or
dystrophic. Lake Mize is a dystrophic lake. Its brown
water is so colored by the leachate from the surrounding
pine forest (Brezonik, 1970) . According to Brezonik
(1970), color values as high as 700 mg/ii , platinum scale,
are common in the lake.
The dissolved and suspended organic materials in
the lake help to produce a distinctly acid pH . Nordlie
(1967) found the median pH of Lake Mize to be 4.2 for
1965. Brezonik (1970) found the median pH to be 5.2
- 16 -
LAKE MIZE
JUNE 24,1954
(CONTOURS IN METERS)
Figure 1. Bathymetric map of Lake Mize, showing sampling
stations 1, 2, 3, and 4. (Courtesy of Dr. Frank
Nordlie)
- 17 -
Figure 2. North-South view of Lake Mize,
Florida.
- 18 -
for the period June, 1969 to June, 1970. Total acidity,
as measured by Nordlie for the 1965 period, ranged from a
low of 10.5 to a high of 30.0 ppm for the surface waters.
Lowest values were obtained during the summer and highest
values during the winter. This range in values shows that
the waters of Lake Mize have a poor buffering capacity
(Nordlie, 1967). Algae and other aquatic organisms in
the lake are consequently exposed to fluctuations in pH
and water chemistry.
The dissolved and suspended organic matter also
affects the penetration of light in Lake Mize. Secchi
disc readings during the period October 2, 1968, to
August 13, 1970, ranged from 1 foot to 4 feet (Table 1).
According to Ruttner (1953) , secchi disc readings in
lowland lakes generally range from a few decimeters to
10 meters. It can be seen that the secchi disc readings
for Lake Mize fall in the lower part of this range. A
secchi disc reading is considered to be a measure of the
depth of visibility in a lake and to give some measure of
the transparency of the water. Measurements made with a
light meter showed light penetrating to around 3 feet
December 9, 1968; to 6 feet on February 9, 1969; and to the
1 foot level on February 15, 1970 (Figure 3).
- 19 -
-p
-p
a
32 48 64 82 98
Percent of surface illumination
Figure 3. Light penetration in Lake Mize, Florida
(Winter) .
- 20 -
TABLE 1
Secchi Disc Measurements in Lake Mize, October 2, 1968
to August 13, 1970
Secchi Reading
Date Hour in feet
October 2, 1968 10:30 a.m. 2-1/4
October 13, 1968 1:00 p.m. 4
December 9, 1968 11:30 a.m. 2-1/4
December 17, 1968 11:30 a.m. 3-1/2
January 9, 1969 4:00 p.m. 2-3/4
February 20, 1969 4:00 p.m. 2-1/2
April 17, 1969 3:00 p.m. 1-3/4
April 23, 1969 3:00 p.m. 1-3/4
November 29, 1969 10:00 a.m. 1
February 15, 1970 3:00 p.m. 1
July 16, 1970 7:00 p.m. 1-1/2
August 13, 1970 5:00 p.m. 1-1/2
Phosphate measurements from the epilimnion of Lake
Mize ranged from nondetectable to 0.1 mg i PO4 for 1965,
according to Nordlie (1967) . And, for the time period of
August 1, 1968, to June 12, 1970, Brezonik (1970) reported
an upward trend in phosphate values with a range from
0.027 mg P/Z to 0.225 P/£.
- 21 -
Nitrate-nitrogen measurements in surface samples
from Lake Mize ranged from a value not detectable to 0.40
mg N/£ during 1965 (Nordlie, 1967). In the deep water,
values occurred up to 0.83 mg N/£ (Nordlie, 1967).
Recently, Brezonik and Harper (1969) have shown that
nitrogen fixation by bacteria occurs in Lake Mize.
Brezonik (1970) reported organic nitrogen values ranging
from 0.55 mg N/ii on August 1, 1968, to 125 mg U/l on
June 12, 1970.
Several studies (Harkness and Pierce, 1941;
Nordlie, 19 67) have shown Lake Mize to be a monomictic
lake, i.e., a lake having one period of circulation during
the year. In Lake Mize constant circulation occurs during
the winter season, generally from November through
February (Brezonik, 1970). Temperature measurements by
the author on December 9, 1968, showed the surface waters
to be 15°C. At a depth of 1 foot, the water measured
14-1/2°C. From the 1-foot level to the bottom, the water
temperature dropped only 1/4°, from 14-1/2° to 14-1/4 °C.
Measurements taken on February 20, 19 69, indicated a
slight stratification. The surface temperature was 17°C
with a drop to 11.2°C at the bottom. (Surface tempera-
tures generally ranged from 16° to 35°C throughout the
year as indicated by Table 2.)
22 -
TABLE 2
Temperature Measurements from the Surface Waters
of the Littoral Zone of Lake Mize,
August, 1968, to August, 1970
Date Hour Temperature, °C.
August 16, 1968 4:00 p.m. 33
August 27, 1968 10:00 a.m. 31
September 3, 1968 1:00 p.m. 26
October 2, 1968 10:30 a.m. 24
November 8, 1968 10:00 a.m. 21
November 15, 1968 2:30 p.m. 20
December 2, 1968 2:00 p.m. 22
January 17, 1969 2:00 p.m. 16
February 20, 1969 3:30 p.m. 18
April 10, 1969 2:00 p.m. 23
May 9, 1969 2:00 p.m. 33
August 8, 1969 2:00 p.m. 35
November 29, 1969 10:00 a.m. 18
February 15, 1970 11:00 a.m. 16
February 15, 1970 3:00 p.m. 18
July 16, 1970 7:00 p.m. 35
July 21, 1970 10:00 a.m. 30
August 13, 1970 2:00 p.m. 29
- 23 -
Without circulation of the lake's waters, a
stable thermal stratification develops. In Lake Mize,
thermal stratification persists from late February or
early March to late October or early November, depending
upon weather conditions (Brezonik, 1970) . During this
period of stratification, anaerobic conditions occur below
a depth of 3 to 5 meters from April or May until the end
of stratification (Brezonik, 1970; Nordlie, 1967). During
the period of circulation and homiothermy , oxygen is
introduced into the deeper waters of the lake (Nordlie,
1967) , although oxygen depletion may still exist in the
deepest waters of the hypolimnion (Brezonik, 1970) .
Nordlie (1967) found the oxygen concentration at a depth
of 70 feet to be 0.5 ppm on December 18, 1964.
Recent History of Lake Mize
The recent history of Lake Mize has included the
introduction of a flock of mallard ducks for scientific
study. During most of the period from August, 1968, until
the present, the ducks have been confined to an enclosure
on the north side of the lake in the bay area. During the
spring and summer of 1970, a portion of the flock was free
to roam on the lake.
In a study to determine the influence of the ducks
on Lake Mize, as well as to evaluate any possible potential
- 24 -
disruptive effects on the lake's ecosystem, Brezonik (1970)
found a trend of gradually increasing phosphate and nitrate
values during the period of August 1, 196 8, to June 12,
1970 (cf. p. 20). He also found chlorophyll a values
during 1969 to be almost twice as high as the values
Nordlie found for 19 65. Primary productivity values also
increased (Brezonik, 1970; Nordlie, 1967). Brezonik
theorized that from 50 to 90% of the duck food being added
to Lake Mize was not utilized by the ducks. This unused
duck food represents a significant portion of the nitrogen
and phosphorus entering Lake Mize at present, according
to his calculations and those of Shannon (1970).
Aquatic Macrophytes of Lake Mize
Some changes in the populations of aquatic
macrophytes also occurred in the 1968-1970 period. During
April, 1968, the following species of floating, submerged,
and emergent aquatic plants were common in Lake Mize:
Paniaum hemitomon , Leersia oryzoides , Websteria submersa ,
Utrioutaria olivacea , Sphagnum maarophyllum , and Mayaca
aubletii. Potamogeton floridanus also occurred in the bay
area of the lake, but was not common or widespread.
Several of the common species gradually decreased over the
2-year period. A survey taken during April, 1970, showed
the following to be absent: S. maarophyllum , L. oryzoides ,
and M. aubletii. The population of P. hemitomon had
- 25 -
increased greatly and surrounded the lake, growing both in
shallow water and on shore. W. submersa was present in
reduced amounts, as compared to the 19 68 survey.
Some of the aquatic macrophytic species of Lake
Mize occasionally grow both submerged and as shore plants.
During periods of low water, submerged aquatic macrophytes
are left stranded on the sloping shore. Such conditions
usually bring desiccation to the aquatic plants. However,
S. macrophyllum , W. submersa, and M. aubletii grow both as
submerged plants in Lake Mize and as terrestrial plants
on shore during low water. This is also a common occurrence
at other soft-water lakes of northern Florida and Georgia.
Sculthorpe (1967) comments that while it is common for
floating aquatic plants to have land forms, few land forms
of submerged plants have been described.
Floating plants also occur to a limited degree in
Lake Mize. Masses of W. submersa, usually mixed with
U. olivaoea, are sometimes present on the surface of the
lake. The floating plant Lemna minor is sporadically
present in Lake Mize.
Surrounding Vegetation of Lake Mize
Besides the land forms of some of the submerged
plants of Lake Mize, there are a number of herbaceous and
shrubby plants around the lake. The herbaceous species
include: Polygonum hirsutum , Hyperiaium myrtifolium ,
- 26 -
Paniaum hemitomon, Fuirena scirpoidea, Rynahospora sp. ,
Cyperus sp. , Eriaaulon deaangulare , Xyris amhigua, Ludwigia
atataj Rhexia mariana , Diodia hirsuta, Pluohea rosea,
Potypremum prooumhens , Elephant opus tomentosus , Eupatorium
oapilli folium, E. aomposiii folium , Osmunda cinnamonea,
Pteridium aquilinum , Hydroootyle umhellata , Sagittavia
graminea, Diodia virginiana, D. teres, Andropogon' sp. ,
Conyza canadensis , and Lyonia lucido. A number of woody
plants, trees, shrubs, and vines border the lake on the
south and west sides. These include: Diospyros virginiana ,
Magnolia virginiana , Myrica oerifera , Ilex glabra, Serenoa
repens , Vaccinium stamineum , Cephalanthus oaoidentalis ,
Quercus hemisphaerioa , Q. geminata, Q. laevis , Q. inaana,
Callioarpa amerioana, Smilax glauoa, S. laurifolia, and
S. bona-nox .
Lake Mize is situated within the body of a pine
forest which surrounds the lake. Important tree species
in the forest include: Pinus palustris , P. taeda, P.
elliotii y Quercus nigra, and Q. laurifolia. The understory
consists largely of Serenoa repens. Ilex glabra and
Vaccinium spp.
The forest, in addition to its influence on the
lake's chemistry and coloring, also provides some measure
of protection from wind.
- 27 -
Elk Lake
In order to compare the perphyton of Lake Mize
with a different kind of lake, a portion of this study
was carried out at Elk Lake, Minnesota. Elk Lake is
located at Itasca Biology Station, Minnesota. It has
a single outflow stream, Chambers Creek, by which it is
also connected to Lake Itasca. Several springs and streams
run into Elk Lake.
Elk Lake has a surface area of 102 hectares, a
maximum depth of 29 meters, a volume of 1.13 x 107 cubic
meters, and a shoreline length of 4.78 x 103 meters
(Baker and Davison, 1966) .
Elk Lake may be characterized as a mesotrophic
lake. It is dimictic, having overturn periods in the
spring and fall. During the winter season it is generally
covered by ice.
The water of Elk Lake is green in color. During the
summer of 1967 light penetrated generally to a depth of
around 10 meters (Figure 4). During the study period, tem-
perature was fairly uniform for the top meters, 24 °C on
July 24, 1967. Below the 4- meter level, there was a rapid
decline in the thermocline to 8°C at the 10-meter level.
At the 29- meter level, temperature registered around 6°C.
- 28 -
16 32 48 64 82 98
Percent of surface illumination
Figure 4. Light penetration in Elk Lake on August 14,
1967.
- 29 -
The littoral area of Elk Lake is populated by a
number of aquatic plants, including several species of
Soirpus . Except for the southwest corner, it is surrounded
by deciduous forest, which provides some protection from
winds .
IV. MATERIALS AND METHODS
General Sampling
The attached algae of Lake Mize, Florida, were
first studied during December, 1968. The study was
concluded in September, 1971. During this study period,
collections were made of the attached algae present in
the littoral area during May, 1969; July, 1969; August,
1969; August, 1970; April, 1971; July, 1971; and September,
1971. Studies of the attached algal species present in
the limnetic area were made during December, 1968;
January, 1969; February, 1969; August, 1969; September,
1969; and August, 1970. Three stations were maintained
in the littoral area and 1 in the limnetic area (Figure 1,
p. 16).
At Elk Lake, Minnesota, glass slides were used
to study attached algal forms present in both the littoral
and limnetic areas during August, 1967. This timing
permitted comparison with the August studies in Lake Mize.
At Elk Lake, 1 station was maintained in the limnetic area
and 1 in the littoral area.
Use of Substrates
A number of substrates were used in studying the
attached algal flora of Lake Mize. Among inert substances,
- 30 -
- 31 -
glass slides were the most commonly used (Figure 5) .
Pieces of plastic were also submerged in the lake tor
attachment by the phyco-periphyton. The aquatic macrophytes
which were sampled for epiphytic growth during the study
included: Sphagnu„ macrophyllu^ , Webst.r-ia submersa,
Famous h.„itomon, Leersia ory.oidee . Mayaoa auilM,
Folyeonu. Ursutu.. and Vt.icula.ia oHva.ea. As previously
mentioned, some of these aquatic macrophytes found at Lake
Mize are amphibious , "i .e . , found growing at time of low
water on the shore as well as submerged in the lake. The
shore forms of these plants were gathered and grown in
closed glass containers in the laboratory. These plants,
assumed to be without epiphytes, were submerged in the lake
in order to study the progressive growth of epiphytic
communities. Because of its frequent occurrence and
physiological hardiness, *'. subn,.vsa was the plant most
commonly used in this way. Other amphibious plants so
used were M. aubleti , S. .acvophyllu. , F. sclvpoidea . and
Baoo^a aaroliniana .
Littoral Area Methods
in the littoral area of Lake Mize, slides and
plants were submerged in rectangular plastic baskets at a
depth of 18 inches (Figure 6). The baskets had a loosely
woven framework. A few were lined with plastic screening
Figure 5. Glass slide showing periphyton present after
3 weeks' exposure in Lake Mize (x 1).
Figure 6. Plastic enclosure used in Lake Mize littoral
studies (x 1/10) .
- 33 -
- 34 -
to provide protected enclosures. Aquatic macrophytes were
planted in sand at the bottom of the baskets. Vertically
positioned glass slides were also placed in the baskets.
The slides were placed in wooden slide boxes which had the
bottoms removed and the boxes were then attached to the
sides of the baskets. The basket enclosures with plants
and slides were generally left in place for varying periods
up to 6 weeks. Occasionally large glass jars were also
used as enclosures for macrophytes. Outside the enclosures
slides in boxes were sometimes attached to upright poles
or to ropes secured by an anchor and buoy. Plants
occurring naturally in the littoral area were also sampled.
Specific methods, collection dates, and exposure
periods differed in the various littoral studies. Details
concerning aspects of each separate study are included in
Chapter V.
Limnetic Area Methods
Comparative studies were made at Lake Mize,
Florida, and Elk Lake, Minnesota, of the attached algae
present in the limnetic areas. In August, 1967, the
attached algal flora on vertical glass slides placed in
the limnetic area of Elk Lake, Minnesota, was studied.
Slides were attached to wooden blocks in which slits had
been cut. The blocks were attached to a rope. The rope
- 35 -
was then attached to a buoy at the surface of the lake
and to an anchor at the lake's bottom. Slides were
suspended at the surface, at l-meter intervals to the 5-
meter level, and at 2-meter intervals from the 7-meter
level to the 15-meter level.
In Lake Mize, 3 similar studies were conducted
during the following time periods: December, 1968, to
February, 1969; July to August, 1969; and July to August,
1970. Slides were placed in wooden slide boxes with the
bottom sections removed. In an arrangement similar to
that carried out at Elk Lake, the boxes were attached to a
rope. The rope was then attached to a buoy and an anchor
and suspended in the middle of the limnetic area of the
lake near the deepest. Since Lake Mize is a brown-water
lake with limited light penetration, slides were placed
nearer the surface than at Elk Lake, Slide racks were
generally attached to the rope at levels of 6, 18, 30,
and 42 inches. In the 1968-1969 winter study and the
August to September, 1969, study, slide racks were also
placed at deeper depths (see p. 50 and p. 63) .
In August, 1970, the sedge, Websteria suhmersa ,
was also suspended on a rope-buoy system during the same
time as the suspension of glass slides. As indicated
earlier, this macrophyte occurred naturally from time to
time in the lake as floating mats, so that its retention
- 36 -
on an artificial rope-buoy approximated the floating state.
Suspensions were made at levels of 6, 18, 30, and 42 inches
with groups of the plants tied to the rope at these levels.
The suspended plants remained alive throughout the study
period. Considerable plant growth occurred at the first
2 levels.
Various exposure periods were used for slides and
plants during the study, ranging from 6 hours to 6 weeks.
Exposure periods and collection dates are enumerated for
each part of the study in Chapter V.
Collecting Procedures
After collecting, plants and slides (Figure 5)
were placed in liquid preservative prepared according to
the following formula.*
Dioxan
50
cc
Formalin
6
cc
Acetic Acid
5
cc
Water
40
cc
This solution preserved most algae so that plastid
color was retained. Algae which were alive at the time of
collection could be distinguished from dead forms.
Species Composition Method
In the Lake Mize limnetic studies and in the
August, 1970, littoral study, proportions and frequency of
*McWhorter and Weier, 1936.
- 37 -
the various species present on glass slides and on some
plants were calculated. With the glass slides, after 1
side of the slide was wiped clean, algae on the unwiped
side were examined directly. Species were usually identi-
fied before any cell counts were made. Counts were made in
2 prescribed areas of the slide, since observation
indicated that algal populations were not evenly distributed
on the slides. On most slides, heavier concentrations of
algae were generally present near the edges of the slides.
Counts were therefore made in 2 areas extending as lines,
as indicated by Figure 7. Along these 2 lines, counts
were made of the algae present in randomly selected fields,
using a 43x objective and a lOx ocular.
Figure 7. Areas counted, indicated by lines, on glass
slides in Lake Mize studies.
In his study of attached algae, Castenholz (1957)
found that counting 300 individuals in randomly selected
microscopic fields gave reasonable statistical accuracy.
- 38 -
In the writer's Lake Mize study, Castenholz ' s counting
procedure was generally followed with the first 300
individuals recorded. Sometimes on sparsely populated
slides, it was necessary to count only 100 individuals.
And, on heavily populated slides, 500 to 1000 individuals
were counted. Frequencies per square centimeter for
individual species and for the total algae present were
calculated. Relative abundance as presented in Table 42
of the Appendix was based on these calculations.
Proportions of the various species among the 300 attached
forms counted were also calculated.
Among the aquatic macrophytes, it was possible to
examine directly the attached flora of S. maorophyllum.
However, the attached algae of most aquatic plants were
observed by scraping off the epidermis with its attached
organisms from a prescribed portion of the plant. Scrapings
were placed on a slide, a drop of water added, and the
mixture stirred. Counts were then made with the first 300
individuals recorded. Proportions of the various
species among the 300 recorded were calculated. In the
case of the linear plant, W. submersa , plant area was
measured before the epidermis was scraped so that frequency
could be calculated for comparison with glass slides.
With the Elk Lake study and with some of the
collections made from the Lake Mize littoral areas, species
- 39 -
proportions and frequency were not calculated.
Identification was made of the species present and
dominants were noted.
Based on frequency calculations or estimates,
several terms are used throughout this study in order to
describe relative abundance of an algal taxon. These
terms and the meaning ascribed to them by the writer are
listed as follows:
1. VeTy Abundant: Over 5000 cells, filaments, or
colonies per square centimeter
2. Abundant: 2000 to 5000 cells, filaments, or
colonies per square centimeter
3. Common: 500 to 2000 cells, filaments, or
colonies per square centimeter
4. Infrequent: 100 to 500 cells, filaments, or
colonies per square centimeter
5. Rave: 10 to 100 cells, filaments, or colonies
per square centimeter
6. Dominant : Algal species present in largest
numbers (numerical dominance)
Physical Measurements
A Whitney light meter was used to measure light
penetrance in Lake Mize. For temperature measurements, a
precision oxygen analyzer was used in the limnetic area
and a pocket thermometer in the littoral area.
V. OBSERVATIONS Al^D RESULTS
The results of the Lake Mize and Elk Lake studies
are organized chiefly according to: (1) the period of the
observation (month and year) and (2) the site of the
observations in the lake, i.e., whether in the littoral
or limnetic area of the lake. Data relating to the
statistical reliability of the observations of this study
are also presented. A master list of the species found in
Lake Mize, Florida, is included in the Appendix (Table 38)
as well as photographs of selected species identified
during the study. A list of species identified from Elk
Lake, Minnesota, is also included in the Appendix (Table 39)
In addition, a third table (Table 40) is included which
presents comparative frequencies of a number of algae
identified during the limnetic studies.
Limitations of the Study
In determining the relative abundance of species
of attached algae under various conditions in Lake Mize,
2 sources of error deserve consideration. One source of
error in making comparisons is derived from the unavoidable
loss of attached material from the substrate while
collecting. This loss of material could be observed both
- 40 -
- 41
in the lake during collection and at the bottom of the
collecting jar after preservation. In making this study,
it was assumed that the amount of material lost from
various substrates while collecting was the same. Precau-
tions were taken while collecting so that the loss of
material was minimal. The material at the bottom of the
collecting jars was also periodically examined for species
which might not appear in the material still attached to
the substrate. Proportions of species in the material at
the bottom of collecting jars were also checked. These
proportions were similar to those proportions of species
remaining attached to the substrate except for slightly
higher losses of metaplanktonic species. The factors
contributing to these losses are discussed in Chapter VI.
Another source of error is the statistical error
found in the counts which provide the basis for some of the
comparisons in this study. Brook (1953) in a study of
bottom-living algae of sand filter beds in waterworks, found
that sampling error for 1 filter bed was around 23% when
10 collections were made. However, because changes in
time were so marked, he still found it possible to make
valid comparisons in his successional study.
The sampling errors in the present study were also
high. For a given algal species, counts made from
replicate substrates frequently showed a variation as high
as that of Brook's study. Occasionally the variation was
- 42 -
even higher (Table 3) . However, significant differences
in frequencies and in proportions among species did commonly
occur under different environmental conditions. Differ-
ences with time were also sometimes marked.
The variation present among counts from
replicate substrates was due to a complex interaction of
factors and will be elaborated upon in Chapter VI.
Lake Mize Studies
Eighty-nine species of algae were identified as
part of the periphyton in Lake Mize or as planktonic forms
associated with the periphyton. Thirteen other species
were present but could not be identified to species,
chiefly due to the lack of reproductive structures in the
Zygnematales and Oedogoniales collected. Of the 102
species present, 63 were Chlorophytes , 2 were Euglenophytes ,
22 were Chrysophytes, 2 were Pyrrophytes, 1 was a
Xanthophyte, and 1 was a Chloromonadophyte.
Colonization of Substrates by Algae
Glass slides placed in the lake and removed after
6 hours were populated by a variety of forms. Many bac-
teria were attached to these slides. Planktonic algae
were common on those slides exposed for a short period of
time. Epiphytic algae common natural substrates in the
lake at the time were also present.
- 43 -
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- 44 -
Slides submerged in the lake for 1 week retained
a clear appearance. However, microscopic examination of
slides from depths of 6 to 18 inches indicated that
several thousand organisms per square centimeter were
present. Slides collected after 2, 3, 4, 5, or 6 weeks'
exposure were partially covered by a film of brown debris.
Accumulation and loss of this debris continued throughout
the exposure period. Several other changes with time
were evident in the periphyton when glass slides exposed
for 1 week were compared with those exposed for several
weeks. The periphyton community on slides exposed from
2 to 4 weeks showed an increase in algal frequency and
in species diversity when compared with that of slides
submerged for one week during the same season. Slides
exposed for periods longer than 3 to 5 weeks sometimes
showed a loss of both debris and associated algae.
Dominant algae present on slides collected after
1 week were usually of the same species as those dominant
on slides collected several weeks later. In the 1968-1969
winter study, Mougeotia sp. made up 23% by count of the
periphyton on slides collected at the 6-inch level on
December 17, 1968. On January 9, 1969, slides collected
at the same level after 4 weeks ' exposure showed higher
algal frequencies and greater species diversity. However,
Mougeotia sp. remained as a dominant, making up 20% of
all the organisms counted.
- 45 -
Colonization of submerged plants followed the
same trends as those of glass slides. During a time
period up to 3 or 4 weeks debris accumulated, algal
frequency increased, and species diversity increased. On
some plants , sharper increases over a period of time
were recorded in algal frequency and species diversity
than on glass slides.
Dispersal or "seeding" units of algae which
colonized submerged slides were generally zoospores,
single vegetative cells, akinetes, or hormogones.
Germlings of Oedogonium and Bulbochaete which had
developed from zoospores were frequently observed on
slides and plants. Single vegetative cells were the
seeding units for most diatoms, desmids, and members of
the Zygnemataceae. During seasons when blue-green
algae were abundant , germinating akinetes were common
on submerged substrates. Hormogones of several species
of the Oscillatoriales were also common then.
The epiphytic algae of Lake Mize showed several
methods of attachment. Many single-celled and filamentous
algae attached along their broad side to the substrate.
This type was represented by such forms as the diatom,
Eunotia, several species of the desmid, Cosmarium , and
several filamentous blue-greens. Other filamentous
forms, as Mougeotia and Oedogonium developed a terminal
- 46 -
cell modified into a holdfast. Attachment to the
substrate was by means of this holdfast with the remainder
of the filament free of the substrate and extending
vertically above it. The single-celled diatom,
Gomphonomena lanaeolatum , also extended vertically above
the substrate, attaching by means of a button of mucilage
on 1 end of the cell. Other algae, termed the meta-
plankton, generally did not attach directly to submerged
slides and plants, but were found floating in the debris
associated with submerged substrates. These forms
associated with debris included a number of single-celled
and filamentous desmids and several filamentous blue-
green algae.
Spatial Variation in the Periphyton in Lake Mize
During the study period both dominance and species
composition varied considerably in the communities of
attached algae present in Lake Mize. At any given point
in time, algal species were generally the same in the
periphyton communities located in separate areas of the
lake. However, proportions of the algal species present
varied on similar substrates in different areas. Slides
placed for a measured period of time at the same depth
in the limnetic area and at various points in the
littoral area had somewhat different algal communities.
- 47 -
Generally, there were some dominant species common on
all slides at all locations. Other species assumed a
dominant role at some locations but not at others.
Several examples may be cited. Prostrate greens such as
Protoderma viride and Coleochaete irregularis were
occasionally common on slides submerged at some littoral
stations. However, during the same period they were
generally rare or absent on slides exposed at other
littoral stations and in the limnetic area. Conversely,
the heterotrophic alga, Rhipidodendron splendidum, \jas
common only on slides suspended in the limnetic area
during August, 1970. Its occurrence was rare on littoral
area slides suspended at the same depth.
Natural substrates in different areas of the lake
also had epiphytic communities of different floristic
compositions. As a rule filamentous Chlorophytes were
the dominant epiphytes on grass culms in the littoral
area, especially several species of Oedogonium.
Collections of Panioum hemitomon from 3 stations in the
littoral zone on the same date generally all contained
Oedogonium as an abundant or very abundant epiphyte. The
co-dominants were usually not the same at the 3 stations.
The filamentous macrophyte, Websteria submersa , also
showed horizontal variations at separate stations in the
lake in regard to its epiphytic flora. W. submersa
- 48 -
frequently supported an epiphytic flora of many desmids.
Generally, some desmids were more abundant on W. submersa
in some areas of the lake than in others. The epiphytic
algal communities on other aquatic macrophytes in Lake
Mize also showed the same trends toward horizontal
variation as did the epiphytic communities on P.
hemitomum and W. submersa.
Vertical differences as well as horizontal
differences were also apparent in the communities of
attached algae in the lake. Light undoubtedly is a
severely limiting factor in Lake Mize. This was
reflected generally in the paucity of attached algae on
slides submerged below a depth of 30 inches. In contrast,
the maximum number of attached algae generally occurred
on slides suspended at a depth of 3 meters in Elk Lake,
Minnesota. In general, slides suspended at various
depths in Lake Mize showed the following patterns of
vertical distribution with reference to the periphyton:
1. Six-inch depth — desmids and other Chlorophytes
abundant or very abundant, Cyanophytes and
Chrysophytes occasionally abundant, species
diversity high.
2. Eighteen and 30-inch depths — Chrysophytes,
especially species of the diatom Eunotia ,
dominant, cell frequency common to very abundant,
Cyanophytes and Chlorophytes occasionally common,
species diversity lower than at 6-inch depth.
3. Forty-two and 54-inch depths — ^Few attaching
algae present, attached protozoans usually the
dominant component of the periphyton.
- 49 -
4. Depths below 54 inches — Attaching forms generally
rare
An exception to the general pattern of vertical
distribution in the periphyton did occur during the 1968-
1969 winter season with respect to one species of Euglena.
This alga was abundant to very abundant on slides
suspended at all depths. (Slides were suspended to a
depth of 6-1/2 feet.) Planktonic algae were also
occasionally found on slides suspended at depths below
54 inches.
Seasonal Variation in the Periphyton in Lake Uize
From season to season and from year to year, the
magnitude of variation in the periphyton was even greater
than in different areas of the lake within the same
season. As could be anticipated, both species composition
and dominance changed from one season to another.
Considerable differences were recorded in communities of
attached algae present in the same season during different
years. These differences occurred mainly at the species
level. Few seasonal changes occurred at the divisional
level. During most of the year, Chlorophytes were
usually dominant in the upper 6 to 18 inches of the lake.
As a rule Chrysophytes assumed a secondary role to
Chlorophytes in this upper vertical layer of the lake.
- 50 -
The most obvious seasonal change in the relative
abundance of the various algal divisions occurred during
the warmer months of late summer and early fall. During
this period (late July — late September) , Cyanophytes
became an important component of the epiphytic flora in
Lake Mize. Conversely, few Cyanophytes occurred during
the winter months in the communities of attached algae.
Attached Algae Present in the Limnetic Area of Lake Mize^
Winter^ 1968-1969
During the 1968-1969 winter study of attached
algae, frames of vertically positioned glass slides were
suspended in the limnetic area of Lake Mize at depths of
80 and 104 inches in addition to the suspensions made near
the surface (see p. 35, Methods). Slides were exposed
from December 9 to 17 (1 week) ; from December 17 to
January 9 (4 weeks) ; and from February 6 to February 13
(1 week) .
Dominant algae on slides during the winter study
included a species of the filamentous Chlorophyte,
Mougeotia, and a species of Euglena. Several species of
the diatom, Eunotia, \^ere also occasionally common on
slides. During this period, species diversity among the
algal communities on slides was high as contrasted with
the two August studies (see Table 40, Appendix). Many of
- 51 -
the species present during the winter study were
Chlorophytes (Tables 4, 5, 6, and 7). Generally, on upper
level slides (6 to 18 inches) suspended during this period,
Chlorophytes were abundant to very abundant; Chrysophytes
were somewhat common, but not as niomerous as Chlorophytes;
and Cyanophytes occurred only rarely (Figure 8 and Tables
5 and 7 ) .
Vertiaal Distribution of Attached Algae on Glass Slides^
December^ 1968 to February^ 1969
Varying patterns of vertical distribution were
observed among the algal species on glass slides suspended
during the 1968-1969 winter period. Euglena sp. was
abundant to very abundant on all exposed slides. The
vertical distribution of this alga was unusual in that
these frequencies occurred on all slides suspended from a
depth of 6 inches to a depth of 6-1/2 feet (Figure 8) .
Most other attached algae achieved such frequencies only
in the top 6 to 30 inches of the lake. A general increase
in frequency for this alga did occur on slides exposed
for 4 weeks as compared to those exposed for 1 week.
However, the abundant frequencies of Euglena sp. on slides
exposed for 1 week were much higher than those of most
other algae after a similar exposure period.
In contrast to the broad vertical range over which
Euglena sp. occurred abundantly, Mougeotia sp. was abundant
- 52 -
O
Si
•H
X!
+»
0)
Q
to
0)
Si
o
•H
XJ
-p
ft
0)
Q
I I J I I I
Frequency: 1 unit = 3,000 cells, filaments,
or colonies per square centimeter
Frequency
1 unit = 3,000 cells, filaments,
or colonies per square centimeter
Figure 8. Frequencies of 3 algal divisions present
on glass slides suspended in the limnetic area
of Lake Mize for 1 week, December 9 to
December 17, 1968, and for 4 weeks, December 17,
1968, to January 9, 1969.
- 53 -
TABLE 4
Dominant Algal Species Found on Glass Slides Suspended
in the Limnetic Zone of Lake Mize for 1 Week,
December 7 to December 17, 1968
■.-=r-;., ■■ ■■■ .-■:.: ■■ t.l^^ - -i — =— :- ■■-
Percent
of the Total
Organ;
Number of
Lsms
Attached
6-inch
depth
(%)
18-inch
depth
(%)
42-inch
depth
(%)
104-inch
depth
(%)
Chlorophytes
Mougeotia sp.
23
10
10
4
Chrysophytes
Eunotia spp.
3
4
6
10
Euglenophytes
Euglena sp.
54
70
70
68
- 54 -
TABLE 5
Proportions of Algal Divisions and Attached Protozoa
Present on Glass Slides Suspended in the Limnetic
Zone of Lake Mize for 1 Week, December 9 to
December 17, 1968
Percent
of the Total Number of
Organisms
Attached
6- inch
depth
(%)
18-inch 42-inch
depth depth
(%) (%)
104-inch
depth
(%)
Algae
Chlorophytes
26
10 11
4
Chrysophytes
12
10 13
18
Cyanophytes
2
1 1
1
Euglenophytes
54
70 70
68
Xanthophytes
3
4 3
6
Pyrrophytes
1
1 1
1
Attached Protozoans ab.
3 2
ab.
Note: ab. = absent
- 55 -
TABLE 6
Dominant Algal Species Found on Glass Slides Suspended in the
Limnetic Area of Lake Mize for 4 Weeks, December 17, 1968,
to January 9, 19 69
Percent of the Total Number of Attached
Organisms
6-inch 18-inch 30-inch 42-inch 80-inch
depth depth depth depth depth
(%)
(%)
{%)
{%)
(%)
Chlorophytes
Mougeotia sp.
20
21
4
1
1
Chrysophytes
Mallomonas sp.*
2
2
6
18
40
Eunotia spp.
5
2
3
1
ab.
Nitschia palea
2
6
3
ab.
1
Euglenophytes
Euglena sp.
54
52
66
72
52
Note: ab. = absent
*planktonic
- 56 -
TABLE 7
Proportions of Algal Divisions and Attached Protozoa Present on
Glass Slides Suspended in the Limnetic Zone of Lake Mize for
4 Weeks, December 17, 1968, to January 9, 1969
Percent of the Total Number of Attached
Organisms
6-inch 18-inch 30-inch 42-inch 80-inch
depth depth depth depth depth
(%)
(%)
(%)
(%)
(%)
Algae
Chlorophytes
26
28
9
1
1
Chrysophytes
12
11
15
19
41
Cyanophytes
3
3
1
3
1
Euglenophytes
54
52
66
72
52
Xanthophytes
2
2
4
4
2
Pyrrophytes
1
1
1
ab.
ab.
Attached Protozoans
1
2
2
1
3
Note: ab. = absent
- 57 -
only on slides exposed for 4 weeks which were suspended at
depths of 6 and 18 inches. At 30 inches, the frequency of
this alga dropped, although it was still common. At depths
below 30 inches, the occurrence of Mougeotia sp. on slides
was rare. However, this was a greater range of depths
than was the case for dominant Chlorophytes on slides
during the summer studies.
Other Chlorophytes which were common on slides at
one or both of the upper two depths included several
species of Oedogonium and a number of desmids. The most
common desmid was Closterium intermedium , although
Cosmarium ovnatum and Closterium setaaeum were also
somewhat common on slides at the two upper levels.
Several Chrysophytes also occurred on slides
during the 1968-1969 winter season. The most numerous
diatoms were Eunotia pectinalis and Nitsahia palea. The
former was common on slides suspended at a depth of
6 inches after 4 weeks' exposure and rare or absent at
depths below 6 inches. The latter was common on slides
suspended at a depth of 6 inches and became abundant on
slides suspended at a depth of 18 inches. It was infre-
quent on slides suspended at a depth of 30 inches and rare
at depths below 30 inches.
Several diatoms reached their greatest abundance
during the winter period. These included Eunotia ourvata
- 58 -
and Frustulia rhomboides . E. aurvata was common on slides
suspended at a depth of 18 inches for 4 weeks and was
infrequent or rare on slides suspended at other depths
during the winter study. During other seasons it was
usually absent in the communities of attached algae found
on plants and slides. Only an occasional cell appeared
in some collections. F, rhomboides occurred regularly in
the periphyton during all seasons of the year. Its
occurrence on slides and on plants was always rare to
infrequent, attaining its greatest frequency during the
1968-1969 winter period.
Few Cyanophytes occurred on winter slides. The
adhering filaments of Phormidium tenue were infrequent on
slides suspended at a depth of 6 inches and were rare or
absent at other depths. In addition to P. tenue several
other Cyanophytes appeared at the 6-inch depth. However,
they were rare even at this level and were generally
absent at still deeper levels.
Several planktonic species were also present on
winter slides. These included the Pyrrophyte, Peridinium
limbatum. Slides suspended during this period were
littered with dead cells of this dinof lagellate, although
some living cells were also present. This alga was the
dominant component of the winter plankton, occurring
- 59 -
exclusively during the cooler months in Lake Mize. A small
species of Mallomonae also appeared on the winter slides.
This planktonic Chrysophyte was common to infrequent on
slides suspended at a depth of 30 inches or less, becoming
abundant on slides suspended at depths of 42 inches and
80 inches (6-1/2 feet). The increase in Mallomonas sp.
with increasing depth accounts for the somewhat "hour-
glass" frequency profile for the Chrysophyta (Figure 8).
Most Chrysophytes at upper levels were diatoms as
discussed previously.
Variation in Algal Flora on Glass Slides with Time, Winter,
1968-1969
When slides collected at various depths on
December 17, 1968, after 1 week's exposure were compared
with those collected on January 9, 1969, after 4 weeks'
exposure, two changes with time were apparent. At all
depths, the frequency of attached organisms was greater
on slides exposed for 4 weeks than on slides exposed for
1 week. The number of species also was greater on slides
exposed for 4 weeks. Twenty species were found on slides
exposed for 1 week as compared to 40 species found on
slides exposed for 4 weeks. Most of this increase in
species diversity occurred at the upper levels (Tables 8
and 9). At the lower levels, little increase in species
- 60 -
TABLE 8
Niamber of Algal Species Present at Various Depths on
Glass Slides Suspended in the Limnetic Area of Lake
Mize for 1 Week, December 9 to December 17, 1968
Number of
Species
6-inch
18-inch
42-inch
104-inch
depth
depth
depth
depth
Chlorophytes
12
5
4
2
Chrysophytes
6
6
5
6
Cyanophytes
1
1
1
2
Euglenophytes
1
1
1
1
Xanthophytes
1
1
1
1
Pyrrophytes
1
1
1
1
Total Number of
Species
22
15
13
13
- 61 -
TABLE 9
Number of Algal Species Present at Various Depths on Glass Slides
Suspended in the Limnetic Area of Lake Mize for 4 Weeks,
December 17, 1968, to January 9, 1969
Numb
er of Spe(
uies
6-
-inch
18-
-inch
30-inch
42-inch
80-inch
d(
Bpth
depth
depth
depth
depth
Chlorophytes
23
21
10
3
3
Chrysophytes
10
9
11
3
3
Cyanophytes
4
4
2
1
2
Euglenophytes
1
1
1
1
1
Xanthophytes
1
1
1
1
1
Pyrrophytes
1
1
1
ab.
ab.
Total Number of
Species
40
37
26
9
10
Note: ab. = absent
- 62-
niimber occurred over a 4-week period. Much of the
increase in species diversity at the upper levels was due
to the increase in desmid species.
Similarities, especially in the proportions of
some dominants, were also apparent when proportions of
Mougeotia sp. on slides collected on December 17, 1968,
after 1 week's exposure were not significantly different
from that on slides collected on January 9, 1969, except
at the 18 inch level where an increase occurred (Tables 4
and 6). At any given depth where slides were exposed,
proportions of Euglena sp. were also similar on the two
dates.
Total desmid frequency did increase between the
two dates, as did the number of species. Ctosterium
intermedium was the only individual desmid to show a
significant numerical increase between 1 week and 4 weeks
at the upper two levels. No increase occurred at the
lower levels.
The number of diatom species were generally the
same at comparable depths on slides exposed for 1 week as
on slides exposed for 4 weeks. Frequency increases were
recorded for Eunotia pectinatis and Nitsahia palea.
Several Chlorophyte and Chrysophyte species were
present on slides collected during February which were
not present on slides collected during December or January.
- 63 -
Most of the new Chlorophyte species were desmids. None
of the species which first appeared in February were
abundant. As in the two previous months, Mougeotia sp.
and Euglena sp. were the dominant genera.
Attached Algae Present in the Limnetic Area of Lake Mize^
August to September i 1969
During the August-September study, the general
methods used in limnetic studies were modified in that
slides were suspended at depths of 54, 66, 120 and 240
inches in addition to the standard suspensions in the
upper 42 inches of the lake. Collections were made on
August 14, 1969, after 1 week's exposure; on August 28,
1969, after 3 weeks' exposure; and, on September 11, 1969,
after 6 weeks' exposure.
Twenty-seven species of algae were identified on
glass slides during the August-September study, 15
Chlorophytes , 6 Chrysophytes, and 6 Cyanophytes. Seven of
the Chlorophytes were desmids, a smaller number of
desmid species than had appeared during the 1968-69 winter
study. The total number of species was also less in the
August to September, 1969, study than in the 1968-1969
winter study. However, the highest organism frequency
recorded on glass slides in the limnetic area of Lake Mize
occurred during August, 1969.
- 64 -
Dominants appearing at upper levels on slides were
chiefly Cyanophytes . These included Phormidium tenue ,
Osaillatopia tenuis, and Aphanoaapsa delioatissima . The
diatoms Eunotia peotinalis and Navioula minima sometimes
reached abundant to very abundant frequencies on slides,
as did the planktonic Chrysophyte, Mallomonas oaudata.
Gleooystis vesiculosa was a dominant on slides exposed
for 1 week from August 7 to August 14.
Vertical Distribution of Attached Algae and Other
Periphyton on Glass Slides, August to September, 1969
The dominant algal species present on slides during
the August to September, 19 69, limnetic study showed
several varied patterns of vertical distribution. The
Chlorophyte, Gleocystis vesiculosa , made up a large
proportion of the periphyton on slides exposed for 1
week (Table 10). On this group of slides, G. vesiculosa
reached its highest frequencies at depths of 30 and 42
inches. The colonies of this alga were common on slides
suspended at depths of 6 inches and 18 inches, becoming
abundant at depths of 30 and 42 inches. Below this depth,
G. vesiculosa was infrequent to rare on slides exposed
for 7 days.
On slides exposed for 3 weeks, G. vesiculosa had
a different vertical distribution from that recorded from
- 65 -
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66 -
slides exposed for 1 week (see Figures 9 and 10) . On
slides exposed for 3 weeks highest frequencies occurred at
a depth of 6 inches. G. vesiculosa was abundant at this
depth and then common to rare at all other depths.
Other Chlorophytes present included several species
of Oedogonium, Ankistrodesmus falcatus , Cosmarium sp.,
Protoderma viride , Soenedesmus dimorphus , Closterium
intermedium , and the planktonic Helicodictyon planatonicum .
All were rare to infrequent. Most of these Chlorophytes
were restricted to slides suspended at 30 inches or above
(Tables 11, 12, 13). However, the desmid,. Cosmarium sp. ,
occurred rarely on slides to a depth of 20 feet, and germ-
lings of Oedogonium sometimes occurred infrequently on
slides to a depth of 10-1/2 feet. The planktonic alga,
H. planatonicum , was also recorded, though rarely, to a
depth of 20 feet.
Among the three dominant Cyanophytes present were
two shade-tolerant species, Phormidium tenue and
Oscillatoria tenuis, which occurred to a depth of 5-1/2
feet. Both species displayed a broad limnological toler-
ance, occurring on slides near the surface as well as at
much greater depths. The highest recorded frequency for
any alga on glass slides during the entire study period
occurred in P. tenue. These exceptionally high counts
were taken from slides submerged to a depth of 6 inches
- 67 -
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Figure 9. Frequencies of 3 algal division and of the
dominant algal species present on glass slides
suspended in the limnetic area of Lake Mize for
1 week, August 7 to August 14, 19 69.
-68-
Frequency ;
1 unit = 3,000 cells, filaments, or
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Frequency:
1 unit = 3,000 cells, filaments, or
colonies per square centimeter
Figure 10. Frequencies of the dominant algal species
present on glass slides suspended in the limnetic
area of Lake Mize for 3 weeks, August 7 to
August 28, 19 69.
-69
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and exposed for 3 weeks. (Higher frequencies for other
algae were recorded on plants.) Frequencies of P. tenue
were also comparatively high at other depths after the
same 3-week exposure period. It was very abundant on
slides exposed at a depth of 18 inches, although a
decrease in numbers from the upper level did occur (see
Figure 10). A gradual decrease of the frequency of this
alga then occurred at lower depths. It was common on
slides suspended at 30 inches, infrequent at 42 inches,
and rare at 54 inches. On slides exposed for 3 weeks at
a depth of 54 inches, P. tenue made up a large proportion
of the periphyton (Table 14) . Although it was rare at
this depth, the numbers of other organisms were compara-
tively lower. The frequencies of this alga were not as
high on slides exposed for either 1 week or 6 weeks as on
slides exposed for 3 weeks. Slides exposed for 1 week on
which colonization had recently begun had frequencies for
P. tenue which ranged from common (6-inch depth) to rare
(54-inch depth) . Losses of Phormidium filaments from
slides exposed for periods in excess of 3 weeks accounted
for its decreased frequency (see Figures 10 and 11) .
0. tenuis did not occur as frequently on slides
during the 1969 summer study as P. tenue. In the case
of slides exposed for 3 weeks, maximum frequency occurred
- 73 -
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1 unit = 3,000 cells, filaments, or
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Figure 11. Frequencies of dominant algal species present
on glass slides suspended in the limnetic area of Lake
Mize for 6 weeks, August 7 to September 11, 1969.
- 74 -
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- 76 -
at the 6-inch depth, although this alga remained common at
successively deeper levels (18, 30, and 42 inches). With
slides exposed for 7 days 0. tenuis attained maximum
frequencies at the 42-inch depth. When slides were left
submerged for periods of 5 to 6 weeks, sloughing of the
periphyton layer reduced the counts for most species.
0. tenuis, for example, was recorded only rarely from
slides exposed for 6 weeks regardless of depth.
Unlike P. tenue and 0. tenuis, Aphanoaapse
delicatissima occurred only on slides suspended in the
upper 18 inches of the lake with most of its growth on
6-inch slides. It was very abundant at 6 inches and rare
at 18 inches on 3-week slides (Figure 10) . Maximum fre-
quencies also occurred at 6 inches on 6-week slides
(Figure 11) .
Other Cyanophytes found on slides during August
and September, 1969, included Calothrix epiphytioa and
Anabaena oscillarioides . Both of these species occurred
only on slides suspended at the depth of 6 inches. C.
epiphytioa was common at this depth and A. oscillarioides
was infrequent at the end of the 3-week exposure period.
A number of Chrysophytes appeared on slides during
the August to September, 1969, study. While not abundant
on slides exposed for only 1 week, Eunotia peatinalis was
a dominant species on slides exposed for both 3 weeks and
6 weeks (Tables 14 and 15). After both exposure periods.
-11-
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- 78 -
frequencies of this diatom were highest on slides suspended
18 inches from the surface, although it was abundant on
slides suspended near the surface at a depth of 6 inches.
A dramatic drop in the numbers of E. peotinalis occurred
between 18 and 3 0 inches. Very abundant frequencies were
recorded on slides suspended at 18 inches while only rare
occurrences were noted at a depth of 30 inches (see
Figures 10 and 11) .
While E. peotinalis was the Chrysophyte present
in largest numbers, several other Chrysophytes were rare
to abundant. These included Mallomonas caudata, Frustulia
rhomboides , Navicula minima^ Gomphonema lanoeolatum, and
Nitsahia palea. This period marked the only recorded
occurrence of G. lanoeolatum on slides in Lake Mize.
Except for M. aaudata, the vertical distribution of
Chrysophytes was mainly limited to the upper 18 inches
of the lake as was the case with E. peotinalis .
A coccoid Xanthophyte, Stephanoporos regularis ,
was also present on the August to September slides. The
vertical distribution of this alga was unusual in that it
occurred chiefly on deeper slides.
Attached protozoans made up a high proportion of
the periphyton on slides exposed for 6 weeks during the
1969 summer study (see Table 16) . Maximum abundance
occurred at the 6-inch level with a gradual decline in
frequency occurring at greater depths. A maximum frequency
- 79 -
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- 80 -
of attached algae for the 1969 summer study occurred on
slides exposed for 3 weeks which were collected August 28.
Vorticelloids occurred infrequently on these slides at
most depths, although they were abundant on slides sus-
pended at the depths of 42 inches (Table 17).
Changes in the Algal Flora on Glass Slides with Time^
August to September , 1969
Glass slides collected on each of three dates
during August to September, 1969, were populated by
several Cyanophyte species. Slides collected on August 14
after 1 week's exposure were dominated by the green alga,
Gleocystis vesiculosa (Tables 10 and 18). After 3 weeks'
exposure the populations of G. vesiculosa showed a marked
decrease. Instead, three Cyanophytes were dominant:
Osaillatoria tenuis, Phormidium tenue , and Aphanoaapsa
delicatissima (Table 14) . Debris covered parts of the
slides, giving them a brown appearance. A significant
increase in algal frequency occurred. Slides collected
on September 11, 1969, after 6 weeks' exposure had lost
most of the debris observed on August 21. Dominance also
had shifted somewhat, so that Cyanophytes and Chrysophytes
were present at upper levels in almost equal proportions
(Tables 16 and 17 and Figure 12). In addition, a decrease
in algal frequency since August 28 had occurred.
- 81 -
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Figure 12. Frequencies of 3 algal divisions on glass
slides suspended in the limnetic area of Lake Mize for
3 weeks, August 7 to August 28, 1969, and for 6 weeks,
August 7 to September 11, 1969.
-82-
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- 84 -
Adaptive Algal Forms Present, August to September, 1969
Attached forms present during the August 14 to
September 11, 1969, period on glass slides tended to be
resupinate, firmly attached along their broadsides. These
included sheathed filaments of Phormidium tenue, colonies
of Aphanocapsa delicatissima, plus those of several other
blue-greens. Some resupinate single-celled forms also
occurred. These included the diatom, Eunotia pectinalis,
and the desmid, Cosmarium bireme . All of these resupinate
forms had a distinct tendency to occur in areas of the
slides which were free of debris. Frequencies for these
forms were also usually higher for the edges than for the
middle portion of slides. (The slide edges were generally
free of debris.) The tendency of the coccoid colony of
A. deliaatissima to appear only on cleared edges of slides
was especially notable.
Whereas the resupinate forms were associated with
cleared areas of slides, other forms were present which
tended to float in the debris that was associated with
slides submerged for several weeks or longer. Many
desmids tended to be associated with this debris. The
filamentous blue-green, 0. tenuis, was the most numerous
of the debris-associated forms during the 1969 summer study,
In his study of the communities of algae in a Michigan
river, Blum (1957) also comments upon the tendency of
0. tenuis communities to be associated with silt, with
- 85 -
these communities generally occurring only on silted stream
bottoms during the summer season. He also notes an apparent
light sensitivity by 0. tenuis in that it occurred mainly
in shaded areas of the stream.
Attached Algae of the Littoral Area, August, 1969
On August 14 and 24, 1969, collections were made
of aquatic macrophytes in the littoral area for determi-
nation of their epiphytic flora. Fuirena scirpoidea.
Polygonum hirsutum, and Panicum hemitomon were collected
on the earlier date from a depth of 18 inches at station 2.
On all macrophytes the epiphytic flora was dominated by
several unidentified species of Oedogonium . On P. hemitomon
a co-dominant was Oscillatoria tenuis. In addition, the
following attached species were recorded from the leaf
sheath: Pleurataenia subooronulatum, Gleocystis vesiculosa,
Mougeotia sp . , Spirogyra sp., Phormidium tenue, Eunotia
pectinalis , Frustulia rhomhoides , and Anabaena oscillarioides
A fresh water sponge was also present on some areas of the
sheath and leaves.
In addition to Oedogonium spp., Coleoohaete
irregularis was a common attached form on the vertical
sheaths of F. scirpoidea. Present on this sedge, but not
as common, were the following species: G. vesiculosa,
Bulbochaete sp., Helicodictyon planctonicum, Stephanoporos
regularis , E. peotinalis , A. oscillarioides , Oscillatoria
tenius y and Hapalosiphon fontinalis .
- 86 -
The sheath of Polygonum hirsutum was populated
mainly by Oedogonium spp. and Oscillatoria tenius with
Oedogonium spp. the .more abundant of the two. Present
also were: G. vesiculosa, F. rhomhoides , and A. oscil-
lavioides .
On August 24, 1969, collections were made from
station 1 of S. maovophyllum and of Fuirena sairpoidea
and from station 3 of W. submersa. S. maovophyllum and
F. soirpoidea were collected from an open area of the
littoral zone while W. submersa was harvested from a
protected plastic enclosure (Figure 6) . All substrates
were taken from depths of 18 inches.
Little similarity was seen between the ephiphytic
communities of the 3 macrophytes . Nor did the species
composition of the communities of attached algae in the
limnetic area resemble that of the aquatic macrophytes,
although the seeding units which populated limnetic area
slides undoubtedly came from epiphytic and epipelic
communities in the littoral area.
The dominant epiphytes present on S. maovophyllum
were Spivogyva sp., Osoillatovia tenuis, A. osoillavioides ,
and Fvustulia vhomboides . Many aseriate packets of
Cyanophyte cells, a morphological form assumed to be a
number of the Nostocaceae, were also present. Other less
numerous epiphytes present included: Oedogonium sp..
- 87 -
Mougeotia sp. , Euastrum binale , Eunotia peatinalis ,
and H. fontinalis .
Fewer species were present on Fuivena soirpoidea
(station 1) than on S. macrophyllum (station 1).
Scrapings from the sheath encircling the stem contained
mainly the coccoid Chlorophyte, G. vesiculosa. Other
epiphytes present were Oedogonium spp. , Mougeotia sp. ,
Coleoahaete irregularis , Staurastrum paradoxum ,
Staurastrum sp. , and Microspora tumidula. A fresh water
sponge was also attached in some areas of the sheath.
A number of species were present as epiphytes
on W. submersa , many of which were desraids. Desmids, in
fact, dominated the epiphytic flora and included:
Cloeterium intermedium , Cl, intermedium var. hibernioum ,
and Cl. libellula var. angusticeps . In addition several
desmids occurred which were not dominants. In this
latter group were: Closterium incurvum , Cl. naviaula ,
Desmidium baileyi , Actinotaenium cruaiferum, Arthrodesmus
incus, A. octocornis , Netrium digitus , Euastrum ciastonii ,
Xanthidium antilopaeum var. minneapoliense , Cosmarium
ornatum , C. bireme , C. blyttii , C. pyramidatum and
Pleurotaenium minutum . Besides desmids, other epiphytes
on W. submersa were Bulbochaete sp. , Oedogonium spp.,
Co leochaete irregularis , G. vesiculosa , E. pectinalis ,
and Nitschia palea.
88
Planktonia Algae, August to September^ 1969
Two vertical plankton tows were made in the
limnetic area of Lake Mize at station 4 during the 1969
summer studies. From a tow made on August 28, the
following species were identified: Eudorina elegans ,
Peridinium westii , and Gonyostomum semen. P. westii was
the most abundant of the three. On September 11, the
most abundant planktonic species was G. semen. Mallomonas
caudata and P. westii were also present. In addition to
planktonic algae, a number of copepods , cladocerans, and
rotifers were also present in the two plankton samples.
Attached Algae Present in the Limnetic Area of
Lake Mize, August, 1970
Glass slides and the aquatic macrophyte, Websteria
submersa, were used to study the attached algae of the
limnetic area of Lake Mize during August, 1970. Collec-
tions of slides and plants were made on, August 13, after
3 weeks' exposure and on August 19, after 4 weeks'
exposure.
Seventeen species were identified on glass and
25 on W. submersa . On both substrates, the majority of
species present were Chlorophytes. A desmid, Cosmarium
vegnellii , and a diatom, Eunotia pectinalis , were the
dominant species present on glass. These two species
were also among the dominants present on W. submersa.
- 89 -
In addition, Mougeotia sp. , Oedogonium spp. , Anahaena
oscillarioides , and Hapalosiphon fontinalis were abundant
as epiphytes on W. suhmersa at one or more depths.
Vertical Distribution of Attached Algae and Other
Periphyton on Glass Slides, August, 1970
During the summer study, as in previous studies,
the different algal divisions and species had different
vertical ranges in Lake Mize. These vertical ranges
were frequently overlapping, however, as was the case
with Cosmarium regnellii and Eunotia pectinalis . These
two algae were commonly found together on slides suspended
at 6 and 18 inches, sometimes reaching abundant frequen-
cies at these depths. The vertical range of E. pectinalis
generally extended deeper than that of C. regnellii.
Although it was either rare or absent in
collections made during most of the study period, C.
regnellii was one of the most abundant epiphytes in Lake
Mize during August, 1970. Unlike most desmids , which
are debris-associated forms of the metaplankton, C.
regnellii attached broadside to the substrate. On slides
exposed for 3 weeks, the highest frequencies of C.
regnellii occurred on slides suspended at a depth of
18 inches. At this level, C. regnellii was abundant
and made up a larger proportion of the periphyton than
any other alga (see Table 19). C. regnellii occurred
- 90 -
TABLE 19
Dominant Algal Species Present on Glass Slides
Suspended in the Limnetic Zone of Lake Mize
for 3 Weeks, July 23 to August 13, 1970
Percent of Total Attached Organisms
6-inch
depth
18-inch
depth
30-inch
depth
42-inch
depth
Chlorophytes
Cosmarium
regne llii
15
ab.
Chrysophytes
Eunotia
peatinalis 33
Rhipidodendron
splendidum
(heterotroph-
ic) ab.
12
Pyrrophytes
Peridinium
westii
Other Algae
6
6
6
7
9
3
11
1
Note;
ab. = absent
91 -
only infrequently on slides suspended at 6 inches, the
depth at which maximum frequencies of Chlorophytes on
glass slides usually occurred. This species was rare
at 30 inches and absent at 42 inches on 3 -week slides.
The frequency pattern of C. regnellii at various
depths was altogether different on slides exposed for 4
weeks as compared to those exposed for 3 weeks. While
maximum frequencies occurred at 18 inches on slides
exposed for 3 weeks, the maximum occurred at 6 inches on
slides exposed for 4 weeks (Figures 13 and 14) . Propor-
tionally, C. regnellii also made up a large share of the
periphyton on 6-inch slides. At other levels, it made
up comparatively little of the periphyton (Table 20) .
In addition to Cosmarium regnellii , six other
Chlorophytes were also present. These included:
Staurastrum setigerum , Closterium naviaula , Protoderma
viride , Coleoahaete irregularis , Staurastrum sp. , and
Oedogonium sp. All were rare on slides at 6 and 18
inches and were generally absent at depths below 18
inches.
During August, 1970, E. peatinalis was the most
frequently occurring Chrysophyte at most depths. On
slides exposed for 3 weeks it was common at 6 and 18
inches, with its frequency dropping to rare at depths
of 30 and 42 inches. The frequency pattern of E.
- 92 -
U3
(D
o
c
•H
P
Frequency:
1 unit = 3,000 cells, filaments of
colonies per square centimeter
Frequency:
1 unit = 3,000 cells, filaments, or
colonies per square centimeter
Figure 13. Frequencies of dominant algal species and the
major groups of attached organisms present on glass
slides suspended in the limnetic area of Lake Mize for
3 weeks, July 23 to August 13, 1970.
- 93 -
u
•H
-P
Q
18-^
30
42
T
H ( 1 h
E
o
s
o
o
H h
M
«
«
o
s
3
PCI
H 1 1 V-
Frequency ;
1 unit = 3,000 cells, filaments, or
colonies per square centimeter
-i — f-
0)
u 18
4-)
0)
Q
30 —
42
to
n3
O
N
o
-p
o
u
u
Frequency ;
1 unit ^ 3,000 cells, filaments, or
colonies per square centimeter
Figure 14, Frequencies of dominant algal species and the
various groups of attached organisms present on glass
slides suspended in the limnetic area of Lake Mize for
4 weeks, July 23 to August 20, 1970.
- 94 -
TABLE 20
Dominant Algal Species Present on Glass Slides
Suspended in the Limnetic Zone of Lake Mize for
4 Weeks, July 23 to August 20, 1970
Percent of Total Attached Organisms
6-inch 18-inch 30-inch 42-inch
depth depth depth depth
(%) (%) (%) (%)
Chlorophytes
Cosmarium
vegneZlii 33
Chrysophytes
Eunotia
pectinalis
7
3
4
4
Dinobryon
caloiforme
ab.
22
17
4
Rhipidodendron
sptendidum
(heterotroph-
ic)
1
11
<1
<1
Other Algae
2
8
12
8
Note: ab. = absent
- 95 -
peatinalis changed somewhat on slides exposed for 4 weeks
where decreases in frequencies occurred at each of the
3 lower levels as compared to slides exposed for 3
weeks. E. peatinalis was infrequent on slides at each
of these depths. At 6 inches beneath the surface E.
peotinalis had a frequency comparable to that observed
for the optimum period of 3 weeks (Figures 13 and 14).
Other Chrysophytes present included Fvustulia
rhomboides , Dinobvyon oalaiforme , Rhipidodendron
splendidum, and Synura sphagnioola (planktonic) . Both
the attached form, P. rhomboides , and the planktonic
form, S. sphagnioola , showed comparable vertical
distributions on slides in the upper 42 inches of the
lake, tending to occur rarely on all slides at all depths.
D. oalaiforme and R. splendidum had higher frequencies
at some depths than at others. The heterotrophic alga,
R. splendidum, had a distinctive frequency curve which
showed maximum frequencies at 30 inches on slides exposed
for 3 weeks and at 18 inches on slides exposed for 4
weeks. R. splendidum was infrequent on the former
(30 inches/3 weeks) and common on the latter (18 inches/
4 weeks) . In slide samples collected from other depths
on both dates, this alga was only rarely present. These
frequencies during August, 1970, were also the highest
- 96 -
recorded during the study period for R. splendidum. Only
an occasional specimen was found in collections made at
other times.
D. calciforme was infrequent on slides exposed
for 3 weeks at the 30-inch depth and was absent at other
depths. However, by the end of the 4-week exposure
period, D. calciforme had become abundant on 18-inch
slides where it was present in greater numbers than any
other alga (see Table 20). The individually attached
cells of D. calciforme also occurred infrequently at 30
and 42 inches-.
Proportionally, Cyanophytes were only a small
part of the algal flora of limnetic area slides during
August, 1970 (Tables 21 and 22). Two species were
present, Anabaena oscillarioides and Hapalo siphon
fontinalis . Both occurred rarely to infrequently on
6^ and 18-inch slides with 3 weeks' exposure. A few
filaments of A. oscillarioides were also present at 30
inches. On slides exposed for 4 weeks, A. oscillarioides
and H, fontinalis occurred infrequently at the 6-inch
level. A. oscillarioides was also rare on 18- and 30-inch
slides. A planktonic dinof lagellate, Peridinium westii,
appeared on slides occurring commonly at all depths.
Heterotrophs formed a conspicuous part of the
periphyton on upper level limnetic slides during the
- 97 -
TABLE 21
Proportions of Algal Divisions and Other Groups of
Organisms Present on Glass Slides Suspended in
the Limnetic Zone of Lake Mize for 3 Weeks,
July 23 to August 13, 1970
Percent
of Total
Attached
Organisms
(
5-inch
depth
(%)
18-inch
depth
(%)
30-inch
depth
(%)
I 42-inch
depth
(%)
Algae
Chlorophytes
15
19
3
<1
Chrysophytes
36
7
11
3
Cyanophytes
19
4
1
ab.
Pyrrophytes
5
6
9
11
Filamentous
Oomycete
36
42
<1
ab.
Attached Protozoans
1
20
56
70
Rotifers
ab.
1
6
14
Note ;
ab. = absent
- 98 -
TABLE 2 2
Proportions of Algal Divisions and Other Groups of
Organisms Present on Glass Slides Suspended for
4 Weeks in the Limnetic Zone of Lake Mize,
July 23 to August 20, 1970
:■-■ •■:■. ■ = ■■ " -: — ~ — : —
Percent
of Total
Number of
Attached
Organisms
6-inch
depth
(%)
18-inch
depth
(%)
30-inch
depth
(%)
42-inch
depth
(%)
Algae
Chlorophytes
42
6
2
2
Chrysophytes
7
39
25
13
Cyanophytes
3
1
3
<1
Filamentous
Oomycete
37
10
1
1
Attached
Protozoans
11
42
67
81
- 99 -
summer of 1970 (Tables 21 and 22) . An unidentified
filamentous Oomycete was abundant on 6- and 18-inch
slides exposed for 3 weeks. After the 4-week exposure
period, it became very abundant on 6-inch slides,
remaining abundant at 18 inches. On slides exposed for
both 3 and 4 weeks it was rarely seen at 30 inches and was
entirely absent at 42 inches.
Several genera of Vorticelloids were also
prominent on slides during this period. These generally
had frequencies which increased with depth in the upper
42 inches of the lake with the largest increase occurring
between 6 and 18 inches.
Variations with Time in the Algal Flora Present on
Limnetic Area Slides, August, 1970
When slides collected on August 13, 1970, after
3 weeks' exposure, were compared with those collected
on August 20, 1970, after 4 weeks' exposure, the species
present and the dominants were much the same . At some
depths differences in proportions at the specific level
occurred between the two dates. Generally, the frequency
of Chlorophytes decreased between August 13 and August 20
on slides suspended at 18 inches or below, while
Chrysophytes increased slightly at depths of 30 and 42
inches .
- 100 -
Vert-ical Distribution Patterns of Attached Algae and
Other Periphyton on Websteria submersUj August^ 1970
Two general types of algal communities were
present on Websteria submersa . The epiphytes on upper
level W. submersa (6 and 18 inches) were organized into
a complex, somewhat stratified community. In this
community, closely adhering, resupinate forms made up
the level closest to the raacrophyte. Filaments
projecting above the resupinate forms made up the second
level. Debris and debris-associated species were then
intermingled with the filaments. The communities present
at 30 and 42 inches were less stratified, dominated by
resupinate forms and resembling the communities found on
glass slides suspended at 6 and 18 inches.
Generally, W. submersa was much more densely
populated by attached forms than in the case of glass
slides. Counts of individual organisms were 6 to 20
times higher on W. submersa than on glass slides at the
same depth. Maximum frequency of organisms on W. submersa
occurred on plants submerged at either 18 or 30 inches
as compared to 6 to 18 inches for glass slides. Species
diversity was greatest at the 6- and 18-inch levels for
W. submersa, as with glass (Tables 23, 24, 25, and 26).
A large variety of Chlorophytes , especially
desmids , appeared as epiphytes on W. submersa (Tables 25
- 101
TABLE 2 3
Number of Algal Species Present at Various Depths on
Glass Slides Suspended in the Limnetic Zone of
Lake Mize for 3 Weeks, July 23 to
August 13, 1970
Number of
Species
6-inch
depth
18-inch
depth
30-
d(
-inch
2pth
1
42-
d(
-inch
2pth
Chlorophytes
1
5
1
Chrysophytes
4
5
4
4
Cyanophytes
2
2
1
0
Pyrrophytes
1
1
1
1
Total Algal
Species
8
13
7
6
102
TABLE 24
Number of Algal Species Present at Various Depths on
Glass Slides Suspended in the Limnetic Area of
Lake Mize for 4 Weeks, July 23 to
August 20, 1970
Number of
Species
6-inch
18-inch
30-
-inch
42-inch
depth
depth
d(
2pth
depth
Chlorophytes
7
6
2
3
Chrysophytes
4
5
5
6
Cyanophytes
3
1
1
1
Total Number of
Species
14
12
8
10
- 103
TABLE 2 5
Number of Algal Species Present at Various Depths on
Websteria submersa Suspended in the Limnetic Zone
of Lake Mize for 3 Weeks, July 23 to
August 13, 1970
Number of
Species
6-
-inch
18-inch
30-inch
42-
-inch
d(
2pth
depth
depth
depth
Chlorophytes
16
12
4
1
Chrysophytes
4
4
6
4
Cyanophytes
4
4
3
2
Total Number of
Species
24
20
13
7
- 104 -
TABLE 26
Number of Algal Species Present at Various Depths on
Websteria submersa Suspended in the Limnetic Zone
of Lake Mize for 4 Weeks, July 23 to
August 20, 1970
Number of
Spe(
3ies
6-
-inch
18-inch
30-
-inch
42-
-inch
d(
epth
depth
d(
-pth
d(
2pth
Chlorophytes
16
12
2
3
Chrysophytes
3
8
2
2
Cyanophytes
4
3
1
2
Total Number of
Species
24
23
5
7
- 105 -
share of the periphyton (Tables 27 and 28, Figure 15).
The most abundant Chlorophyte was the desmid, Cosmarium
regnellii (Tables 28 and 29). This desmid, also abundant
on glass slides, had a tendency to form short chains
while adhering closely to the substrate.
Maximum frequencies of C. regnellii occurred at a
depth of 18 inches after both 3- and 4-week exposure
periods (see Figures 15 and 16). This alga was also very
abundant in samples taken from the 6-inch depth on both
August 13 and August 20. With plants exposed for 3
weeks, a sharp decline in the numbers of cells of C.
regnellii occurred between 18 inches (point of maximum
frequency) and 30 inches. Considerable growth of C.
regnellii occurred at the 30-inch depth between August 13
and August 20 so that on W. submersa exposed for weeks at
this depth, C. regnellii was very abundant. Frequencies
then dropped to rare at 42 inches.
A second desmid which was sometimes present as
an epiphyte on W. submersa was Closterium navioula.
While the frequencies of this alga did not approach those
of Cosmarium regnellii , it was nevertheless abundant at
some depths. Generally, highest frequencies occurred at
18 inches, as in the case of Cosmarium regnellii . At
6-inch depths, Closterium navioula was also abundant.
- 106 -
c
•H
c
-H
+j
a.
0)
Q
18 —
30
42 —
Frequency;
1 unit = 3,000 cells, filaments, or
colonies per square centimeter
CO
u
Q
18+ g^
o
42-1-^
s
•^
s
•ri
-5^
r~i
^
V~i
a
<»
E
e
w
<a>
■s^ o
Q)
^\ '^
^ ^
^ ' ' ' ' I — \ — I I I ' I I I I I I I I I I I I I I I — '
Frequency
1 unit = 3,000 cells, filaments, or
colonies per square centimeter
Figure 15. Frequencies of dominant algal species present
on Websteria submersa suspended in the limnetic area
of Lake Mize for 3 weeks, July 23 to August 13, 1970.
- 107 -
Frequency
1 unit = 3,000 cells, filaments, or
colonies per square centimeter
OJ
u
c
•H
4-1
Oi
QJ
Q
18--
30--
42--
Frequency :
1 unit = 3,000 cells, filaments, and
colonies per square centimeter
Figure 16. Frequencies of dominant algal species present
on Wehstevia submersa suspended in the limnetic area
of Lake Mize for 4 weeks, July 23 to August 20, 1970.
- 108 -
TABLE 2 7
Proportions of Algal Divisions Present on Websteria
submersa Suspended in the Limnetic Zone of Lake
Mize for 3 Weeks, July 23 to August 13, 1970
■ ■■: ; . : :=■■..= ::
Percent of the Total Number
Attached Organisms
of
6-inch 18-inch
depth depth
(%) (%)
30-inch
depth
(%)
42-inch
depth
(%)
Chlorophytes
Chlorophytes
65 46
15
1
Chrysophytes
9 17
14
16
Cyanophytes
24 9
3
2
- 109 -
TABLE 28
Proportions of Algal Divisions and Attached Protozoa
Present on Websteria submersa Suspended in the
Limnetic Zone of Lake Mize for 4 Weeks,
July 23 to August 20, 1970
Percent
of Total
Attached
Organisms
6-inch
depth
(%)
18-inch
depth
(%)
30-inch
depth
(%)
42-inch
depth
(%)
Algae
Chlorophytes
44
68
27
2
Chrysophytes
7
30
72
57
Cyanophytes
45
2
1
1
Attached
Protozoans
<1
<1
<1
1
-110-
TABLE 29
Dominant Algal Species Found on Websteria submersa
Suspended in the Limnetic Zone of Lake Mize for
3 Weeks, July 23 to August 13, 1970
Percent of the Total Number
Attached Organisms
of
6-inch
depth
(%)
12-inch
depth
(%)
30-inch
depth
(%)
42-inch
depth
(%)
Chlorophytes
Cosmarium
regnel Hi
40
36
12
<1
Mougeotia sp.
11
3
<1
ab.
Chrysophytes
Eunotia
peotinalis
5
13
14
7
Cyanophytes
Anabaena
osaillarioides
11
3
1
1
Hapalosiphon
fontinalis
10
1
ab.
ab.
Other Algae
21
11
9
14
Attached
Protozoans
2
25
62
75
Note: ab. = absent
- Ill -
TABLE 30
Dominant Algal Species Found on Websteria submersa
Suspended in the Limnetic Zone of Lake Mize for
4 Weeks, July 23 to August 20, 1970
Percent of the Total Number of
Attached Organisms
6-inch
depth
(%)
18-inch
depth
(%)
30-inch
depth
(%)
42-inch
depth
(%)
Chlorophytes
Cosmarium
vegne ZZii-
27
48
26
Chrysophytes
Eunotva
■peotinalis
5
27
72
52
Cyanophytes
Anabaena
Oscillarioides
33
<1
ab.
ab.
H ap at o siphon
fontinalis
11
<1
ab.
ab.
Other Algae
12
11
1
9
Note: ab. = absent
- 112 -
At 30 and 42 inches, it was rare or absent (see Figures 15
and 16) . This desmid was usually a resupinate form which
appeared to adhere closely to the substrate. Sometimes
it was associated loosely with the substrate or with
debris.
In addition to Cosmariwn regnellii and Closterium
naviaula, many other desmids were also present in the
limnetic area on W. submersa. These included: Cosmarium
amoenum , C. pyramidatum , C. bireme , Staurastrum setigerum ,
S. orbiculare , Closterium libeltula , Euastrum binale ,
Onahyonema laeve var. latum, and Bambusiana brebissonnii .
All of these were metaplanktonic forms which were loosely
associated with the substrate or with debris, rather than
closely adhering to a surface. C. pyramidatum , S.
setigerum , and S. orbiculare were all common epiphytes of
VI. submersa at the 6-inch level, after 3 weeks' exposure
of the macrophytes. Each of the three desmids was
infrequent at 18 inches and rare or absent at deeper
levels. The other desmids listed above were all rare to
infrequent at depths of 6 and/or 18 inches.
Filamentous Chlorophytes which attached to y.
submersa included an undetermined species of Mougeotia
and three undetermined species of Oedogonium. Numeri-
cally, filamentous Chlorophytes did not form as large a
- 113-
proportion of the periphyton as did several of the
single-celled desmids. However, the tangled mass of
filaments had an important structural role in the epiphytic
communities by providing a means of entrapment and reten-
tion for loosely associated desmids and blue-greens.
Mougeotia sp. was the most abundant of the
filamentous Chlorophytes. It was very abundant at the
6-inch level after both 3 and 4 weeks' exposure. At other
levels, Mougeotia sp. was rare to infrequent. Oedogonium
spp. occurred infrequently at 6 and 18 inches after 3 and
4 weeks. These species of Oedogonium were totally absent
at greater depths.
Two large prostrate Chlorophytes, Protoderma
viride and Coleochaete irregularis , also occurred rarely
on W. submersa suspended at 6 or 18 inches. These algal
epiphytes were never found to be abundant on the
filamentous W. submersa, although high frequencies
sometimes occurred on littoral area slides and on broad-
leaved aquatic macrophytes.
Eunotia peotinalis was the dominant Chrysophyte
present on W. submersa during August, 1970. Maximum
frequencies of this alga occurred at the 18-inch depth
on plants exposed for 3 weeks with common frequencies
recorded for 6, 30, and 42 inches. On plants exposed for
114 -
4 weeks, maximum frequencies were at the 30-inch depth.
E. peotinalis was then very abundant at 18 and 42 inches
and common at 6 inches. It was, by far, the dominant alga
on plants submerged at 30 and 42 inches with a vertical
range extending deeper than that of desmids, filamentous
Chlorophytes , or blue-greens.
Other Chrysophytes which were epiphytes or were
associated with W. submersa included: Dinobryon
oytindricum (planktonic) , Synura sphagnicola (planktonic) ,
Frustutia rhomboides , Dinobryon aalai forme , and
Rhipidodendron sptendidum . D. aalaiforme and the
planktonic S. sphagnicola occurred rarely throughout the
entire vertical range of 42 inches. R. sptendidum was
absent from all depths except 42 inches, where it was a
rare epiphyte with frequencies much below those which
had been recorded from glass slides. F. rhomboides
occurred irregularly (rare to common) on W. submersa at
all depths. Occasionally it was absent. The planktonic,
D. cylindrioum , was associated with W. submersa exposed
for 3 weeks at all depths. This species was rare to
abundant.
It was not unusual for planktonic forms to become
associated with or trapped by communities of attached
algae. For such planktonic forms, bimodal or "hourglass-
type" frequency diagrams were representative.
- 115 -
e.g., Figure 15. (A few attached forms, as F. rhomboides,
also sometimes had bimodal frequency diagrams.)
Planktonic dinof lagellates , frequently found on
submerged glass slides, were not usually associated with
W. submersa and other aquatic macrophytes in Lake Mize.
During August, 19 69, the vertical range of the
dominant Cyanophytes on glass slides {Phormidium tenue
and Oscillatoria tenuis) extended to a depth of 66 inches.
During August, 1970, the vertical range of the dominant
blue-green epiphytes of W. submersa was quite reduced in
comparison. Both Hapalosiphon fontinalis and Anabaena
osaillarioides occurred almost exclusively at the 6-inch
depth on W. submersa. At the 6-inch depth they were each
abundant to very abundant. At 18 inches, only a few
specimens were found (Figures 15 and 16) . Both species
were absent at 30 and 42 inches. (They also occurred
mainly at the 6-inch depth on glass slides where they
were much less abundant than on W. submersa, cf. . p. 94).
The attaching forms of these two blue-greens
were usually different. The branched filaments of H.
fontinalis were tightly attached to the substrate. In
contrast, the filaments of A. osaillarioides were usually
locsely associated or intermingled with the vertical
filaments of both Mougeotia sp. and other Chlorophytes.
- 116 -
A. osaillarioides was also observed at times adhering to
the substrate in a prostrate position.
Variations with Time in the Algal Flora Present on
Websteria submersa^ August^ 1970
When the Websteria submersa collected on
August 13, 1970 (3 weeks' exposure) was compared with
that collected on August 20, 1970 (4 weeks' exposure),
certain differences became apparent, particularly at the
depths of 6 and 30 inches. At 6 inches, an increase in
Cyanophytes occurred especially in the number of filaments
of Anabaena osaillarioides . Many of the filaments on
August 20 were short, the product of a recently germinated
akinete. There were also a number of akinetes present.
The increase in A. osaillarioides was accompanied also by
an increase in Cosmarium regnellii . At 30 inches, an
increase in populations of Eunotia peotinalis occurred
between August 13 and August 20 (see Figures 15 and 16) .
At other depths, frequencies and proportions of
most algae showed little change over the 7-day period.
Nor did frequencies of Mougeotia sp. and E. peatinalis
change significantly at the 6-inch depth. The number of
species at all depths was also similar on August 13 and
August 20 (Tables 25 and 26) , although some of the rare
- 117 -
species were different. At the upper levels (6 and 18
inches), these rare species were mainly desmids.
Comparison: Algal Flora of Glass Slides and of
Websteria submersa, August, 1970
The community of attached algae on glass slides
and on Websteria submersa during August, 1970, contained
many of the same species. Some dominants were also the
same. However, marked differences were observed in the
proportions and frequencies of algal species on the two
substrates. Higher frequencies were recorded for most
species of algae on W. submersa than on glass slides.
Desmids, filamentous Chlorophytes, and blue-green algae
also formed larger proportions of the periphyton on W.
submersa than on glass slides.
9
The desmid, Cosmarium regneltii , was a major
component in the algal flora of both glass slides and W.
submersa. At all depths higher frequencies of this
desmid were recorded on W. submersa than on glass slides
(Table 31) . These differences were especially evident
on substrates submerged at depths of 18 and 3 0 inches.
On August 20, 197 0, there were approximately 100 times as
many cells of C. regnellii present on W. submersa,
suspended at a depth of 6 inches, as on glass slides.
And, at 30 inches, there were over 150 times as many
cells of this alga on W. submersa as on glass slides.
- 118 -
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- 122 -
A number of other desmids, rare or absent on
glass, were also associated with W . submersa (Table 31) .
Stauvastrum setigevum was a common epiphyte on 6-inch W.
submersa on August 13. It was rarely present on glass
slides. Also, on August 13, Cosmarium pyramidatum was
abundant on W. submersa but was absent from glass.
Altogether, 13 desmid species occurred as epiphytes on
fv'. submersa while 5 species were associated with glass
slides on August 13. Data for August 20 were similar.
Filamentous Chlorophytes also occurred more
frequently on W. submersa than on glass slides. Mougeotia
sp. was absent on glass slides during August, 1970. Yet,
on both August 13 and August 20, 1970, this species was
very abundant on W. submersa at 6 inches. [Mougeotia sp.
did occur on glass slides during January, 1969, cf.
p. 57).
Differences were also observed in the frequency
of blue-green algae on glass slides and on W . submersa
as has been mentioned previously. At 6 inches, blue-
green algae were infrequent on glass slides; however,
Hapalosiphon fontinalis was abundant and Anabaena
oscillarioides was very abundant on W. submersa suspended
at 6 inches.
As with Chlorophytes and Cyanophytes, higher
numbers of most Chrysophyte species occurred on W.
- 123 -
submersa than on glass slides (Table 31). These
differences were especially obvious at depths of 18, 30,
and 42 inches. One common species on both glass and on
W. submersa was the diatom, Eunotia peotinalis . This
species always had higher frequencies on W. submersa
than on glass slides. This difference may be illustrated
by two examples. On August 20, 1970, 65 times as many
cells of E. peotinalis occurred on f/. submersa as on
glass at 18 inches. And, at 30 inches, the difference in
cell density, f/efcs terta/glass increased to 200/1.
While higher diatom frequencies occurred on W.
submersa, in contrast, the heterotrophic Chrysophyte ,
Rhipidodendron splendidum, reached a higher frequency
on glass. This alga was only rarely found at 42 inches
as an epiphyte on W. submersa. However, it was a common
attached form on glass slides suspended at some depths.
Several other categories of organisms were more
abundant on glass slides than on W. submersa. Most
planktonic algae were more abundant on glass, and a
filamentous Phycomycete was abundant to very abundant on
upper level slides (6 and 18 inches) but was rare on W.
submersa .
Planktonic Algae, August 13, 1970
Two algal species were identified from a
vertical plankton tow in the limnetic area of Lake Mize
- 12 4 -
on August, 1970. These were Peridinium westii and
Stephanoporos regularis , the former being more abundant
than the latter. Both of these species were also some-
times present in the periphyton during August, 197 0.
As previously mentioned, planktonic species in
Lake Mize were more commonly trapped by the periphyton of
slides than that of aquatic macrophytes.
Attached Algae of the Littoral Area, August, 1970
A study of the attached algae present in the
littoral area of Lake Mize was undertaken during August,
1970, to parallel the limnetic area studies carried out
at the same time. Slides and aquatic macrophytes were
collected from glass and plastic enclosures at
station 1 on August 15. On August 20, collections of
slides and plants were also made from a glass enclosure
at station 2. In each case, substrates were submerged
at a depth of 18 inches and collected after an exposure
period of 4 weeks. Plants and slides from open areas of
the littoral zone were also gathered on these two dates.
In addition, collections were made of glass and plastic
slides suspended in an area of the littoral zone near
station 1 which was exposed to currents. These slides
were submerged at the depth of 18 inches from April 30,
1970, to August 20, 1970.
- 125 -
As during previous littoral studies, diverse
coinmunities of attached algae were found on the different
plants and slides collected during August, 1970.
Floristic composition varied from one area of the lake to
another and even from one slide to another in the same
area.
While some species were broadly distributed over
the lake, others were confined to specific locations or
were more abundant in some parts of the lake than in
others. Although no substrate specificity by any algal
species could be demonstrated, frequencies and relative
proportions of various algae were dissimilar on different
plants and on artificial substrates used, e.g., glass and
plastic. (Some harvested plants were exposed for a
measured period. For others, which grew naturally in the
lake, recording of the exposure period was not possible.)
Several differences were evident in comparing
the periphyton on slides at stations 1, 2, and 4 submerged
at the same depth (18 inches) . Slides in the littoral
area (stations 1 and 2) showed a total organism frequency
which differed little from the organism frequency on
slides at the 18" inch level in the limnetic area
(station 4) . However, 40% of the organisms on slides
in the limnetic area were protozoans and fungi. In the
littoral area, most attaching forms were algae. Proto-
zoans and fungi together constituted less than 1% of the
- 126 -
attached biota. Other differences were also apparent.
The spreading, prostrate alga, Protoderma vivide, was
common on slides at both stations in the littoral area.
It did not appear on glass slides in the limnetic area.
Another prostrate alga, Coleochaete irregularis , was
common on glass slides at station 2. It was rare to
infrequent on plastic slides submerged in the limnetic
area, but was not present on glass slides at either
station 1 (littoral) or station 4 (limnetic) .
Chlorophytes were generally more abundant on
littoral area slides than on limnetic area slides,
although many of the species present were the same.
Cosmarium regnellii was a widely distributed attached
species in Lake Mize during August, 1970. At 18 inches
in the limnetic area, it was infrequent on glass slides.
It was over 10 as times abundant on glass slides in a
protected enclosure at station 1 than on 18- inch limnetic
area slides. At station 2, frequencies of C. regnellii
were not as high as at station 1, although it remained
abundant.
Blue-greens were also more abundant on littoral
area slides than on limnetic area slides. As with the
prostrate green species, differences also occurred
between stations 1 and 2. One species, Anabaena
oscillarioides , occurred rarely on 18- inch slides in the
- 127 -
limnetic area. This species was also rare at station 1.
It did not appear on slides at station 2. At station 1,
two closely adhering, filamentous forms, Lynbya
novdgaardii, and Hapalosiphon fontinalis , were common on
slides. At station 2, L. nordgaardii was rare while H.
fontinalis was abundant. Both L. nordgaardii and H.
fontinalis were absent on limnetic area slides at this
depth. Dinobryon aalciforme and Rhipidodendron splendidum
were rare on slides at both littoral stations. On 18-
inch slides in the limnetic area the former was abundant
and the latter common.
Attached Algae on Glass and Plastio Slides, Littoral
Area, August, 1970
The glass and plastic slides submerged at a depth
of 18 inches in an exposed area of the littoral zone
from April 30, 1970, to August 15, 1970, had a flora
dominated by diatoms. Eunotia peotinalis , E. vanheurakia
var. intermedia, and E. zygodon were the most abundant
species. A significant difference occurred in the
frequency of these 3 diatoms on glass and plastic.
Collectively, they were 5 times as frequent on plastic
as on glass. Total organism frequency, as well as the
number of species, was also higher on plastic (see Tables
32 and 33) . However, species diversity on neither
- 123 -
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- 130 -
plastic nor glass in the area exposed to currents was as
high as that on glass in protected areas at stations 1
and 2. Total organism frequency on glass in the 3 areas
was similar.
The macrophytes submerged in a plastic enclosure
for 4 weeks at station 1 included W. submersa and S.
maorophyllum . Several naturally growing plants were also
collected on August 15 from a depth of 18 inches. These
included Utrioularia olivacea , Panioum hemitomon and
Polygonum hirsutum .
The most abundant epiphytic species appearing on
W. submersa at station 1 after 4 weeks' exposure were
Cosmarium vegnellii , Ctosterium navicula, Mougeotia sp.,
and Eunotia pectinalis . Frequencies of the two tightly
adhering dominants, C. vegnellii and E. peatinalis , and
the filamentous Mougeotia sp. were comparable to those
on 18-inch limnetic W. submersa while frequencies of the
loosely associated CI. navicula and Anabaena
oscillarioides were not the same on 18-inch limnetic
and littoral f/, submersa . Cl. navicula was 5 times more
abundant and A. oscillarioides was 20 times more abundant
in the littoral area at 18 inches than in the limnetic
area at the same depth.
All five dominants had higher frequencies on
littoral W. submersa than on vertically positioned glass
- 131 -
slides in the same enclosure. C. regnellii was over 10
times as abundant on W. submersa as on glass while Cl.
naviaula was 70 times more frequent on W. submersa as on
glass slides. A. oscillarioides and Mougeotia sp. were
both abundant on W. submersa while occurring only rarely
on glass.
The other epiphytic algae present from the
littoral area are listed in Table 34. Generally, the
broad, prostrate greens common on glass were rare on W.
submersa. Several other algae, including the small
Chrysophyte, Peroniella planctonica , were also more
abundant on glass than on the filamentous f/. submersa.
Sphagnum maarophyllum had a reduced algal flora
as compared to that of W. submersa in the same plastic
enclosure. The number of algal species appearing on
the two macrophytes, however, was about the same (see
Table 33) . The most abundant species occurring on S.
maarophyllum were Cosmarium regnellii , Closterium
naviaula , Anabaena osaillarioides , and Eunotia peatinalis.
These four species were also dominants on W. submersa
where frequencies were several times greater than on S.
maarophyl lum .
During August, 1970, tangled masses of the
bladderwort, Utriaularia olivaoea, occupied much of the
- 132 -
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- 134 -
littoral area at station 1, extending several feet below
the surface and into the perforated plastic enclosure.
Usually, this macrophyte was observed only in the floating
state. Samples of this filamentous aquatic plant taken
from outside the plastic enclosure had a flora unlike
that of other macrophytes or of glass slides at station 1.
The dominants present were Eunotia zygodon, E. pectinatis ,
Coleochaete irregularis , and Protoderma viride. During
the study period, E. zygodon was recorded as abundant
only on U. olivacea, although it was sometimes rare to
infrequent on other substrates. Other epiphytes which
occurred on U. olivacea were Aphanochaete repens,
Oedogonium spp., Gleoaystis vesiculosa, Cosmarium
regnellii , Mougeotia sp. , Stephanoporos regularis ,
Lynbya nordgaardii , and Hapalosiphon fontinalis .
Samples of U. olivacea taken from inside the
plastic enclosure had an aquatic flora similar to that
of the W. submersa, also inside the enclosure. The most
abundant species on U. olivacea were Cosmarium regnellii,
CI. navicula, Mougeotia sp., and A. osaillarioides . The
other species present were Euastrum binale^ Protoderma
viride, G. vesiculosa, Microspora tumidula , Onchyonema
laeve var . latum, Oedogonium sp. , Bulboohaete sp., and
L. nordgaardii .
Both leaf and stem sheaths of Paniaum hemitomon
and Polygonium hirsutum were examined for epiphytes.
- 135
Oedogonium spp. was a dominant on both areas of Taniaum
hemitomon with Cosmarium regneltii also a common epiphyte
on the leaves, but not on the vertical, hairy sheath
where it was infrequent. Most algal species occurring on
P. hemitomon were present on both leaves and sheaths.
These included: CZosterium naviaula , S. regutaris ,
Mougeotia sp. , Bulbochaete sp. , Spirogyra sp., G.
vesiculosa , Nitschia palea, Frustulia rhomboides , E.
peotinalis , E. zygodon , and A. osaittarioides .
The hirsute leaves of Polygonum hirsutum were
covered by a mucilaginous layer containing L. nordgaardii
and an unidentified filamentous Oomycete. The other
epiphytes present on the submerged leaves of P. hirsutum
were: Cl . naviaula , Staurastrum setigevum , Cosmarium
vegnellii , G. vesiculosa, Bulbochaete sp. , E, peotinalis ,
and H. fontinalis .
Sheaths ot _ Polygonum hirsutum , which are also
hirsute, were not covered by the mucilaginous layer
containing L. nordgaardii and the filamentous fungus,
although a few specimens of L. nordgaardii were present.
Oedogonium spp. and H. fontinalis were the most abundant
epiphytes with the following also recorded: 0. laeve var,
latum, Closterium navicula , Cosmarium regnellii , C.
amoenum, G, vesiculosa, Euastrum binale, Bulbochaete sp. ,
- 136 -
Frustulia rhomboides , Eunotia pectinalis , E. zygodon,
N. palea, and H. fontinalis.
At station 2, located in a protected area of the
lake, the following macrophytes were submerged at 18
inches for 4 weeks in a glass enclosure: Sphagnum
macrophyllum , Baaopa caroliniana , Mayaoa aubleti , and
Fuivene sairpoidea. The floating angiosperm, U. olivacea ,
was also gathered from the surface of the lake near the
glass enclosure.
S. macrophyllum had an epiphytic flora at station 2
which was dominated by C. regnellii , Oedogonium spp.,
and A. oscillarioides . Two of these algae (C. regnellii
and A. oscillarioides) were among the dominants on S.
macrophyllum at station 1. The other epiphytes present
also included a number of desmids as observed at station 1.
These were: Cosmarium hireme , C. pyramidatum , Onchyonema
laeve var . latum, and Closterium navicula. In addition,
the following epiphytes were also present: Bulhoahaete
sp. , Coleochaete irregularis , Protoderma viride, Mougeotia
sp. , N. palea, E. pectinalis , A. oscillarioides , and
H. fontinalis .
The lower leaves of B. caroliniana at station 2
had an epiphytic flora not clearly dominated by any one
alga. The most numerous species included Coleochaete
- 137 -
irregularis , Protoderma viride, Cosmarium regnellii ,
C. bireme , Oedogonium sp. , E, pectinalis , and H.
fontinalis . Except for Oedogonium sp. , all were
resupinate forms which adhered closely to the surface of
the broad, horizontally oriented leaves of B. caroliniana.
Nineteen species of algae were present. In addition to
the above, records show the presence of Mougeotia sp. ,
Closterium navicula , Euastrum binale , Cosmarium amoenum ,
Staurastrum setigerum , Desmidium baileyi , N. palea,
F. rhomboides , and L. nordgaardii .
The upper leaves of B. caroliniana were sparsely
populated with only a few attached forms present. No one
species was dominant as a pioneering attacher on the new
leaves.
Seven species of attached algae were present on
M. aubleti. Oedogonium spp. , and Coleochaete irregularis
were the most common epiphytes. The other species present
were Mougeotia sp. , Eunotia pectinalis , A. oscillarioides ,
and L. nordgaardii .
The dominant epiphytes were Cosmarium regnellii ,
E. pectinalis , and A. oscillarioides on the vertical
stems of F. sairpoidea at station 2. These were all common
attached species at this time on many of the aquatic
macrophytes present at stations 1 and 2 and on W. submersa
- 138 -
artificially suspended in the limnetic area. In addition,
the following were recorded from F. sairpoidea:
Cosmarium bireme , C. amoenum, Mougeotia sp. , Oedogonium
sp. , Protoderma vivide^ E. pectinatis , F . rhomboidesj
H. fontinalis , and A. osoillarioides .
Other Littoral Studies , May, 1969; July, 1969;
April, 1971; July, 1971; and September, 1971
In addition to the observations of littoral algae
made during August, 1969, and August, 1970, collections
of aquatic macrophytes and their epiphytes were also
made during May, 1969; July, 1969; April, 1971; and
July, 1971. In addition, glass slides were exposed at
littoral stations during the periods April to May, 1969,
and August to September, 1971.
Collections were made on May 9 and May 20, 1969.
On May 9, collections were made from two plastic
enclosures at station 2 of glass slides, of Mayaaa
aubletii , of Websteria submersa , and of Sphagnum
macrophyllum . All were exposed at a depth of 18 inches
for 2 weeks.
In the first plastic enclosure, glass slides
were covered by bryozoans. Attached to the bryozoans,
but not directly to the slide, was the blue-green alga,
Hapalosiphon fontinalis. The dominant alga present on
- 139 -
slides was Phormidium tenue which occurred mainly in areas
of the slides near the bryozoans. In addition, a number
of desmids were present. These included Cosmarium
hiveme, C. o ma turn , C. pyramidatum , Euastrum ciastonii ,
E. affine, Micrasterias fimbviata, Tetmemorus bvebissonii ,
Closterium navicula , Cl . intermedium , and Netrium digitus.
Other epiphytes included Protoderma viride , Oedogonium
sp. , Neidium ladogense var . densestriatum , Eunotia
pectinalis , E. vanheurokia var. intermedia , Nitsahia
palea, and the planktonic dinof lagellate, Peridinium
limbatum,
S. macrophyllum was populated by seven algal
species, none of which were abundant or dominant. These
included: two unidentified species of Oedogonium; the
desmids, Spirotaenia aondensata, Cosmarium regnelliij C.
bireme, and Closterium intermedium', and the diatom,
Eunotia pectinalis .
The diatoms, E. pectinalis and E. vanheurokia
var. intermedia were abundant on W. submersa at station 2.
In addition, the following epiphytes were present:
Cosmarium bireme, C. regnellii , Oedogonium spp., and
Frustulia rhomboides .
Glass slides taken from the second plastic
enclosure at station 2 were more densely populated than
those taken from the first enclosure. Also, bryozoans
- 140 -
were not present as in the first enclosure. The dominant
species on slides taken from the second enclosure were
N . palea (diatom) and Stephanoporos regularis (Xanthophyte) .
On the edges of the slides, three resupinate species,
Aphanocapsa deliaatissima , P. vivide , and E. pectinalis ,
were abundant. The other attached species recorded from
the slides were Micrasterias fimbriataj Closterium
intermedium J Cl. incurvum ^ Gleooystis vesiculosa,
Oedogonium sp. , Spirogyra sp. , F. rhomboides, Pinnularia
gibba, and Phormidium tenue.
S. macrophyllum and M, aubleti removed from the
second enclosure were sparsely populated with infrequent
epiphytes. The following were recorded on S. maarophyllumi
Oedogonium spp. , Bulboohaete sp. , Stephanoporos regularis ,
Closterium inaurvum , Cosmarium bireme ^ F. rhomboides ^
N. palea, E. pectinalis , and A. deliaatissima. M. aubleti
was even more sparsely populated than Sphagnum macrophyllum ,
having Micrasterias fimbriata, Mougeotia sp., and
Spirogyra sp. as the only epiphytes. In his study of the
phyco-periphyton in several oligiotrophic lakes, Foerster
(1964) observed that colonization of glass slides by
attached algae proceeded faster in earlier successional
stages than on aquatic macrophytes. In later stages
production on aquatic macrophytes exceeded that on glass
slides. The present writer's study tends to confirm
- 141 -
these observations. Algal frequencies were greater on
slides after 2 weeks' exposure during April to May, 1969,
than on macrophytes. Foerster's second observation was
also confirmed for the filamentous aquatic macrophytes
which were present. For example, substantially greater
algal frequencies were found on Websteria submersa after
3 to 4 weeks' exposure than on glass slides (cf. p. 1L6 ) .
On May 20, 1969, a number of collections were
made from station 3. From a glass enclosure after 6 weeks'
exposure at 18 inches, W. submersa , M. aubleti, and
Sphagnum maorophytlum were collected. The following
naturally growing species were also collected from a depth
of 18 inches at station 3: Panicum hemitomon , M. aubteti ,
Leersia orysoides , and Utriaularia olivaoea.
W . submersa, collected from the enclosure, had the
following epiphytes: Oedogonium sp., Spirogyra sp.,
Bulbochaete sp. , Gleocystis vesiculosa, Coleoahaete
irregularis , Mougeotia sp. , Cosmarium bireme , C.
pyramidatum , Desmidium baileyi , E. peotinalis , and
Rhipidodendron splendidum . None were abundant.
M. aubleti, also collected from the enclosure,
had a somewhat different flora from that of W. submersa.
Several closely appressed forms were common to abundant:
Cosmarium bireme, C. regnellii , Coleoahaete irregularis ,
and E. peotinalis . Other epiphytes included: Oedogonium
- 142 -
sp. , Bulbochaete sp. , Spirogyva sp., M. fimbriata,
Onohyonema laeve var . latum, E. zygodon, and A.
osaillarioides .
The S. macrophyltum from the enclosure had a still
somewhat different algal flora. The appressed species,
Cosmavium hireme and H. fontinalis , and the filamentous
Oedogonium spp. were abundant. Also present were:
^seriate packets of an unidentified member of the
Nostocaceae, Cosmavium ornatum , Aotinotanium eruoiferum,
Closterium intermedium, G, vesiculosa, Mougeotia sp. ,
Bulbochaete sp., R. splendidum, Eunotia pectinalis , and
F. rhomboides . The small Chrysophy te , Lagynion
soherffellii, was also present as an epiphyte on a single
Oedogonium species.
The leaves and stems of the naturally growing
grasses, Panicum hemitomon and Leersia oryzoides taken
■from station 3 on May 20, 1969, were covered by a fila-
mentous mat composed of several unidentified species of
Oedogonium . The other epiphytes present on the leaves of
P. hemitomon were: Pleurataenia subcoronulatuw ,
Cosmavium py rami datum , C. blylii, C. vegnellii , Clostevium
intermedium, Cl. incuvvum , Cl. libellula , Cl. setaceum ,
Coleoohaete irregularis , Gleocystis vesiculosa , Mougeotia
sp. , E. pectinalis, A. oscillarioides , and H. fontinalis.
- 143 -
In addition to the leaves, several of the
adventitious roots of P. hemitomon were also examined for
epiphytes. These roots were filamentous, extending into
the water rather than anchoring the plant. The epiphytic
community present was unlike that on the leaves. Oedogonium
spp. remained dominant but was not as abundant as on the
broad leaves of this macrophyte. The filamentous Moug eotia
sp. and several closely adhering species, Cosmarium
regnellii , C. bireme, Coleochaete irregularis , and
H. fontinalis , were also abundant. The other species
recorded were: Pleurataenia subcoronulatum and E. pectinalis .
L. oryzoides had few epiphytes besides Oedogonium spp.
The other species present were Coleochaete irregularis ,
Mougeotia sp. , and H. fontinalis .
The floating macrophyte, U. olivacea , also had an
epiphytic flora dominated by Oedogonium spp. The filamen-
tous desmid , Pleurataenia suhooronulatum , was a subdominant.
The other epiphytes recorded were: Mougeotia sp. ,
Coleochaete irregularis , and H. fontinalis .
At station 3, the naturally growing M. aubleti
had a unique epiphytic flora as compared with the other
macrophytes sampled on May 20, 1969. Two closely adhering
forms Protoderma viride (Chlorophyte) and Aphanocapsa
deliaatissima (Cyanophyte) were co-dominants. Also
present, but not as abundant were Oedogonium spp.,
- 144 -
G. vesiculosa , Cosmarium hireme , Aphanoohaete repens ,
E. peatinalis , and E. zygodon.
On July 26, 1969, Panioum hemitomon (natually
growing) was collected from each of the three littoral
stations. In each case the portion of the plant sampled
was the vertical leaf sheath. Sheaths were collected from
a depth of 18 inches.
At station 1, the most abundant epiphytes on the
leaf sheat of P. hemitomon were the metaplanktonic Pleura-
taenia subcoronulatum and four unidentified species of
Oedogonium . (Many Oedogonium gerralings were present.)
Coteoahaete irregularis , Cosmarium regnellii , and
Oscillatoria tenuis were common epiphytic species. Other
species with rare to infrequent occurrences were Mougeotia
sp., Cosmarium hireme, Netrium digitus , Onohyonema laeve
var. latum, Hyalotheca dissiliens , Closterium inourvum ,
CI. navicula , Frustulia rhomboides , E. pectinalis , E.
zygodon , Nitschia palea , Stephanoporos regularis , and
Anabaena osaillarioides .
At station 2, Panicum hemitomon also had an algal
flora dominated by Oedogonium spp. Again, many of the
specimens present were germlings. Two other filamentous
greens, Mougeotia sp. and Spirogyra sp., were sub-dominants
Additional epiphytes present were: Closterium incurvum ,
- 145 -
Cl. navioula, Cosmavium hiveme , C. amoenum , G. vesiculosa,
Bulboohaete sp. , F. rhomboides , and E. peatinalis . The
filamentous desmid, Pleurataenia subcoronulatum , abundant
at station 1, was absent at station 2.
The Panicum hemitomon gathered from station 3
supported an epiphytic flora dominated by Oedogonium spp. ,
as observed at stations 1 and 2. As at station 1,
Pleurataenia subcoronulatum was a co-dominant. The other
members of the epiphytic community at station 3 were:
G. vesiculosa, Staurastrum paradoxum , Cosmavium ornatum ,
Closterium incurvum , and Onchyonema laeve var. latum.
On April 30, 1971, spring winds had uprooted a
portion of the aquatic macrophyte, W. submersa, so that it
was present both in the rooted and floating states.
Collections were made of this plant from stations 1 and 2
and at several intermediate points between the two stations.
At station 1, collections were made of rooted plants from
a depth of 6 inches. At station 2, floating plants were
gathered as well as rooted plants from depths of 6 and 9
inches. Macrophytes collected from intermediate points
were taken from depths of 6 or 9 inches.
At station 1, a microscopic examination of W.
submersa (depth of 6 inches) showed the macrophyte to be
covered by the Xanthophyte, Stephanoporos regularis , and
- 146 -
by the diatom, E. peatinalis . Both of these epiphytes were
very abundant. A limited number of other species were
present including: Cosmarium pyramidatum , Helicodiatyon
planatoniaum , E. zygodon , and Neidium ladogense .
E. peatinalis was also the dominant epiphyte on
W. submersa at station 2 (6-inch depth) with Aphanooapsa
deliaatissima as a sub-dominant. The other epiphytes
included: Closterium intermedium , Cl. naviaula ,
Spondylosium pulchetlum vslIC . bambusinoides , Staurastrum
paradoxum , C. regnetlii , Oedogonium sp. , Protoderma
viride , Scendesmus dimorphus , and E. zygodon. The desmid,
Spondylosium pulohellum ■vbli:. bambusinoides , was present
only in the collections made on April 30, 1971.
The floating W. submersa at station 2 had presumably
drifted into the area from other parts of the lake. On
these plants the epiphytic community was not the same as
that on the W. submersa rooted at a depth of 6 inches.
G. vesiculosa was the dominant species present. Sub-
dominants (frequency "common") were: Mougeotia spp. ,
Phormidium tenue , Closterium naviaula , E. vanheurakia var.
intermedia , and E. peatinalis . Other species with rare
to infrequent occurrences included: Cosmarium bireme ,
C. regnellii , Spondylosium pulahellum var. bambusinoides ,
Mierasterias fimbriata , Staurastrum paradoxum, Oedogonium
- 147
sp. , Coleoohaete irregularis , F. rhomboides , Nitsahia
palea, and Peridinium limbatum (planktonic) .
E. peatinalis (diatom) and Closterium navicula
(desmid) were the dominant species on W. submersa collected
from a depth of 9 inches between stations 1 and 2. A
number of desmids other than Cl. naviaula were also
present. These included: Cosmarium bireme , C. regnetlii ,
C. blyttii , C. pyramidatum , C. amoenum , Closterium
intermedium , Arthrodesmus incus, and Spondylosium pulahellum
var. bambusinoides . Epiphytes, other than desmids, were
Oedogonium sp. , Mougeotia sp. , Saendesmus dimorphus ,
Stephanoporos regularis , F. rhomboides , E. peatinalis ,
E. vanheurckia var. intermedia , E. aurvata , Dinobryon
euryostoma , Osoillatoria tenius , and Aphanoaapsa
de lioatissima .
W. submersa was collected from a depth of 6 inches
at a second intermediate point between stations 1 and 2.
As on most samples of this macrophyte gathered on April 30,
1971, E. peatinalis was abundant. Co-dominant with E.
peatinalis were two other species, Protoderma viride , and
A. delioatissima. Other epiphytes were: Staurastrum
paradoxum , Cosmarium pyramidatum, C. bireme, C. blyttii ,
Closterium naviaula, and Spondylosium pulahellum var.
bambusinoides .
- 148 -
On July 31, 1971, W. submersa , gathered from a
depth of 12 inches at station 1, was densely populated by
epiphytes. Both Mougeotia spp. and Anabaena osaillavioides
were very abundant. Micvospora pachyderma was common.
Other species with densities ranging from rare to infre-
quent were: Spirogyra sp. , Bulboahaete sp. , Aphanochaete
repens , Staurastrum paradoxum , G. vesiculosa , Closterium
intermedium , Ct. setaaeum , Dinobryon bavarioum , E.
peatinalis , Osoillatoria tenius , and H. fontinatis .
For 5 weeks, from August 6 to September 3, 1971,
6-inch slides were exposed at station 2. At the time of
collection approximately 50% of the slide area was
covered by a fresh-water sponge, Spongilla sp. The
remaining areas of the slides were thickly populated by
attached algae, especially blue-greens. Several Cyanophy-
cean species appeared for the first time in collections on
September 3, 1971.
The blue-green, Anabaena osaillarioides , was one
of the dominants on slides. Filaments of this alga were
attached directly to the substrate. Such a manner of
attachment in this species contrasts sharply with that
observed at other times during the period of study when
A. osoillatarioides was part of the raetaplankton. Other
blue-greens present included aseriate packets of an
- 149 -
unknown member of the Nostocaceae, Anabaena lapponiaa,
A. variabilis , Aphanocapsa delioatissima , Lynbya
nordgaardhii , 0. tenius , and H. fontinalis.
The small diatom, Naviaula minima, was very
abundant on slides during September, 1971. This alga
showed a distinctly clumped distribution, covering some
areas of a slide while being absent from other portions.
Other attached diatoms were Neidium ladogense , Nitsahia
palea, E. pectinalis , and F. rhomboides . Attached members
of the Chrysophyceae were Dinobryon bavariaum and D.
aalci forme .
The most abundant Chlorophyte present was the
loosely associated desmid, Staurastrum leptoaladum . Other
Chlorophytes included S. pavadoxum , Euastrum binale ,
Cosmarium regnellii , C. biveme , Closterium navicula ,
Protoderma viride , Coleoahaete irregularis , Charaaium
ambigium , Sahoederia setigera, Mougeotia sp. , Oedogonium
sp. , and Spirogyra sp.
A Xanthophyte, Stephanoporos regularis , which
sometimes appeared in the attached flora of Lake Mize,
was also present on slides during September, 1971.
Planktonio Algae , September 2^ 1971
On September 3, 1971, a bloom of the green alga,
Heliaodiotyon planotonioum , occurred in some areas of
- 150 -
the lake. This alga occasionally appeared in the plankton.
At times it was also trapped by the periphyton, although
it did not appear on slides during September, 1971.
Elk Lake Studies
The attached algae of Elk Lake, Minnesota, were
studied during a 6 -week period in the summer of 1967,
from July 1 to August 4. Results differed from the July
to August studies at Lake Mize, Florida, and are presented
here for comparative purposes.
Twenty-five species of algae were identified
during the study period. Several other species present
could not be identified, due, in some cases, to a lack of
reproductive structures. Of the 34 species present, 19
were diatoms, 7 were Cyanophytes, and 8 were Chlorophytes.
Generally, diatoms dominated the attached flora in both
the limnetic and littoral areas, although a few Chloro-
phytes and Cyanophytes were sometimes abundant. This
domination by diatoms was in striking contrast to Lake
Mize, where desmids and other Chlorophytes generally
dominated the attached flora. The majority of the species
present in Lake Mize were also Chlorophytes.
Collections of slides were made from littoral and
limnetic stations on July 28 after one week's exposure, on
- 151 -
August 4 after 2 weeks' exposure, and on August 14 after
3-1/2 weeks' exposure. Collections were also made of some
slides in the limnetic area on August 14 after 6 weeks'
exposure and of Sairpus sheaths from the littoral area.
As in the Lake Mize limnetic studies , colonization
patterns that appeared on slides were studied from a
comparative view with regard to: {l)time — ^the succession
of attached forms that appeared from week to week at a
given depth in the lake; (2) spaae — differences in the
types of attached algae that appeared on slides in the
different vertical layers of the lake. Dominance on
slides was determined by counts and estimates. One slide
from each level per week was examined.
Vertiaal Patterns of Attached Algae and Other Periphyton
on Glass Slides in Elk Lake, July to August, 1967
On each of the three collections dates, the
greatest number of organisms attached to slides suspended
at depths of 1 and 3 meters. Organism frequency was also
high on slides suspended at the depth of 2 meters. A
substantial reduction in organism frequency occurred on
slides submerged at a depth of 4 meters. Below the depth
of 4 meters, organism frequency was low on slides. At
these lower levels, most attaching algae occurred on that
protected portion of the slides near the wooden rack.
- 152 -
Fourteen diatom species, 1 Chlorophyte species, and 1
Cyanophyte species appeared on limnetic area slides on
July 28.
Several attaching diatoms had high frequencies
on slides collected on July 28, 1967, after 1 week's
exposure. Colonization patterns were similar on slides
submerged at each of the upper 4 levels. The diatoms,
Aahnanthes minutissima and Cocaoneis plaoentula , were the
most abundant species present. Other diatoms which were
somewhat numerous included: Synedra radians , Epithemia
zebra, Epithemia turgida , Gomphonema tanaeolata , and
Cymbella affinis. At meter 4, the blue-green, Oscillatoria
quadripunatulatai ^as also an important component of the
algal flora.
Slides collected on July 28, 1967, below the depth
of 4 meters had a sparse algal flora. The algae present
in limited numbers at these lower levels were chiefly
Tabellaria flocculosa , A. minutissima, a.nd C. placentula.
The algal flora of slides collected on August 4,
1967, after 2 weeks' exposure, was dominated by the diatom,
A. minutissima at the upper 3-meter levels. Large numbers
of this small diatom were present, attached broadside to
the slides. Sixteen diatom species, 2 Chlorophyte species,
5 Cyanophyte species, and 1 species of Euglena were
present on slides in the limnetic area.
- 153 -
On slides at the 1-meter level, A. minutissima
made up 90% of the attached flora. At meter 2, dominance
was shared by A. minutissima and G. lanaeblatum. At a
depth of 3 meters, A. minutissima and 0. quadripunctulata
were the most abundant algae. At a depth of 4 meters, the
diatom, C. placentula , and the green algae, Mougeotia sp. ,
Oocystis sp. , and Radiococcus nimbatus , were the most
important components of the algal flora. A. minutissima ,
abundant at the upper levels, was present only in limited
numbers.
Below meter 4, algal frequency was low with
Tabellaria floaculosa and Cyolotella bodin present in low
frequencies.
The communities of attached algae present on
slides at the 3-meter depth in the limnetic area of Elk Lake
on August 14, 1967, after 3 weeks' exposure, showed more
variation than on earlier dates (Tables 35, 36, and 37).
At the upper two levels, species diversity was comparatively
low and A. minutissima continued to be a dominant, making
up 51% of the attached flora on slides at meter 1 and 86% at
meter 2. 0. quadripunatulata was also abundant on slides
at the 1-meter level. Both of these algae attached
broadside to the slides, adhering closely to the substrate.
- 154 -
TABLE 35
Number of Algal Species Present at Various Depths on Glass
Slides Suspended in the Limnetic Area of Elk Lake,
Minnesota, for 1 Week, July 21 to July 28, 1967
Numb^
er of Spec
ies
1-Meter
depth
2-Meter
depth
3-Meter
depth
4-Meter
depth
6-Meter
depth
Chlorophytes
1
ab.
ab.
ab.
ab.
Chrysophytes
9
11
13
11
8
Cyanophytes
ab.
1
ab.
2
ab.
Total Number
of Species
10
12
13
13
8
Note: ab. = absent
- 155 -
TABLE 36
Number of Algal Species Present at Various Depths on Glass
Slides Suspended in the Limnetic Area of Elk Lake,
Minnesota, for 2 Weeks, July 21 to July 28, 1967
Numb^
er of Species
1-Meter
2-Meter
3-Meter
4-Meter
6-Meter
depth
depth
depth
depth
depth
Chlorophytes
ab.
ab.
ab.
2
1
Chrysophytes
13
11
11
9
6
Cyanophytes
1
ab.
5
1
ab.
Euglenophytes
ab.
ab.
ab.
1
ab.
Total Number
of Species
14
11
16
13
7
Note;
ab. = absent
- 156 -
TABLE 37
Number of Algal Species Present at Various Depths on
Glass Slides Suspended in the Limnetic Area of
Elk Lake, Minnesota, for 3-1/2 Weeks,
July 21 to August 14, 1967
Numb
er of
Spe
:;ies
1-Meter
depth
2-Meter
depth
3-Meter
depth
4-Meter
depth
6 -Meter
depth
Chlorophytes
ab.
ab.
2
2
1
Chrysophytes
10
8
14
8
2
Cyanophytes
3
ab.
5
2
ab.
Euglenophytes
ab.
ab.
1
1
ab.
Total Number
of Species
13
8
22
13
3
Note: ab. = absent
ma
- 157 -
Two protozoans, Vorticella and Actinophyrs, \fere numerous
on slides at the upper two levels.
Slides submerged at a depth of 3 meters were
covered by a thick film of brown debris. Dominance was
shared by four algal species. Two of these, A. minutissi
and 0. quadripunctulata , were forms which attached
directly to the substrate. Two others, Gomphosphaeria
laaustvis and Synedra radians, were associated with the
debris and did not adhere closely to the slides. Species
diversity was also higher on slides at meter 3 than at
other levels (see Table 37). The attached protozoan,
Vortiaella , was the chief grazer present.
Slides at the 4-meter level did not have the
thick film of debris which had been present on slides at
meter 3. A. minutissima and S. radians were the most
abundant algae on slides. The protozoans, Vorticella and
Aatinophyrs , vjere abundant on slides at the 4-raeter level.
Again, slides suspended at levels below 4 meters
were only sparsely populated by algae and other attached
forms.
Slides were also collected from the 3-meter level
on August 14, 1967, after 6 weeks' exposure. These slides
were covered by a thick coat of debris. The dominant
- 158 -
algae were forms which tended to drift in the debris
rather than attach firmly to the substrate. Gomphosphaeria
lacustris made up 46%, Rhopalodia gibba made up 30%, and
Cymbella affinis made up 18% of the algae associated with
meter 3 slides after 6 weeks' exposure. At this time,
the blue-green, G. lacustris , and one of the diatoms^ R.
gibba, were also present in the plankton (Baker, 1967).
Both were also found on the sediments and as epiphytes on
Soirpus in the littoral area.
Variation with Time in the Algal Flora Present on Glass
Slides, Elk Lake Limnetic Area, August , 1967
Resupinate forms were the pioneers in colonizing
glass slides at the upper 4 levels. The diatoms, A.
minutissima and C. plaoentula, were prominent on slides
after 1 week's exposure. Both of these species were
examples of the resupinate type.
Prostrate forms continued to be abundant on slides
after 2 weeks' exposure during August, 1967. At 3 of the
4 upper levels, ^4. minutissima continued to be abundant.
A closely adhering blue-green, 0. quadripunctulata , became
abundant also on slides at a depth of 3 meters. And, the
colonial greens, Radiococcus nimbatus and Oocystis sp.,
became abundant on slides at the 4-meter level. Both of
these colonial algae were embedded in mucilage which also
adhered to the substrate.
- 159 -
On slides at each of the upper 3- meter levels,
Gomphonema lanoeolatum became abundant. This alga
represented a second attaching form to become abundant
on slides in Elk Lake. Cells of G. lanoeolatum attached
vertically to the substrate via a button of mucilage on
one end of the cell. The green filamentous species,
Mougeotia sp. , also became abundant on slides at a depth
of 4 meters. This species attached vertically to the
substrate as did G. lanoeolatum. Attachment for Mougeotia
sp. was by means of a holdfast.
After 3 weeks' exposure, resupinate forms
remained dominant on slides at meter levels 1 and 2. At
meter 3, a thick film of debris had formed. Two of the
prostrate species remained abundant. However, 2 other
abundant species, Gomphosphaeria laoustvis and Synedra
radians, were forms associated with the debris on slides.
S. radians was also the most abundant species at meter 4.
Slides exposed for 6 weeks at meter 3 carried the
successional tendency further. Three species, G. laoustris ,
Rhopalodia gibba, and Cymbella af finis, ^ere abundant. All
3 were species which loosely associated with the substrate,
tending to float in debris rather than attach directly to
the slide.
Round (1964) in commenting upon the communities of
attached algae which make up successional stages on glass
- 160 -
slides, states that slides primarily attract a mixture of
species from epiphytic and epilithic habitats. After this
initial colonization, he observed that slides secondarily
trap species from the epipelic and planktonic habitats.
Slides exposed at the depth of 3 meters in Elk Lake during
August, 1967, for 3 or 6 weeks, did secondarily trap
planktonic species. This trapping occurred after the
accumulation of debris on the slides.
Attached Algae of the Littoral Zone, Elk Lake ^ August, 1967
Colonization of slides placed at depths of 5 meters
and 1 meter in the littoral area of Elk Lake was similar
to the colonization of slides placed in the limnetic area
at the upper 2-meter levels. Aohnanthes minutissima was
a dominant on slides at each weekly collection period.
Other major species, Cooooneis placentula , Gomphonema
lanaeolatum , Cymbella af finis , Synedra radians, and
Epithemia zebra, were also found on limnetic area slides.
The differences which did exist between littoral area
slides and upper level limnetic slides included the
appearance of a prostrate green alga, Coleoahaete
orbioularis . Grazers were also more diverse on slides in
in the littoral zone. Aatinophrys appeared on slides
during the first week with hypotrichs , attaching rotifers,
ciliates, and gastrotrichs appearing the second week.
- 161 -
Gastrotrichs and rotifers were also present during the
third week, moving easily about in the debris attached to
slides. Except for the hypotrichs, which fed on Achnanthes
minutissima , the feeding habits of these invertebrates
were not observed.
The epiphytic algae of the aquatic macrophyte ,
Scirpus sp. , in the littoral area of Elk Lake were also
examined. Epiphytes which were present on both Scirpus
and on glass slides included E. zebra, E. turgida,
Ehopalodia gibba, Amplipleura pellucida , Cymbella af finis ,
Nitschia palea , Amphora ovalis , Gomphosphaeria laaustris ,
and Radiooooous nimbatus . The chief epiphyte, not present
on glass slides, which was present in large quantities on
Scirpus was a species of Oedogonium. Achnanthes
minutissima , Cocconeis placentula , and Oscillatoria
quadripunctulata were not detected on Scirpus. However,
this was probably due to the difficulty of obtaining the
closely adhering forms in scrappings from Scirpus , not
to their absence.
Comparison: Attached Algae of Lake Mize, Florida, and Elk
Lake, Minnesota
Few of the species of attached algae found in the
dystrophic Lake Mize, Florida, and the mesotrophic. Elk
Lake, Minnesota, were the same. Two diatoms, Nitschia
palea and Gomphonema lanceolatum , and 1 Chlorophyte,
- 162 -
Tvotoderma viride , were the only species common to both
lakes. The chemical differences in Lake Mize and Elk Lake
were reflected in an almost completely different alga
flora in the two lakes. Some of the floristic differences
in the two lakes may be elaborated on as follows:
1. A large number of desmids were present in Lake
Mize whereas only single specimens of a few
species were found in Elk Lake.
2. Diatoms formed the majority of the attached flora
in Elk Lake while diatoms were generally
subdominant to Chlorophytes in Lake Mize.
3. The most common diatoms in Lake Mize were
several species of the genus, Eunotia. In
contrast, Aahnanthes minutissima was the most
frequently appearing diatom in the flora of
Elk Lake.
General similarities between the attached flora of
the two lakes should also be cited. Closely adhering
filamentous Cyanophytes appeared on the slides of both
lakes during the month of August, although the species
were different. In Elk Lake, Oscillatovia quadripunatulata
was sometimes abundant on limnetic area slides, while the
closely adhering Phormidium tenue was abundant in Lake
Mize during August, 1969. Large, prostrate Chlorophytes
appeared on littoral area slides in both lakes. In Elk
Lake, Coleoohaete orbioularis was common on slides while
Protoderma viride and Coleoohaete irregularis were
frequently common to abundant on littoral area slides in
- 163 -
both lakes. Prostrate greens were also absent or rare
on limnetic area slides in both Elk Lake and Lake Mize.
In both lakes, closely adhering, resupinate forms
made up many of the pioneering species which attached to
recently submerged substrates. In Lake Mize, filamentous
species were also sometimes included among the first
attachers to a bare substrate. These were rare on Elk
Lake slides except at the depth of 4 meters. Conversely,
few stalked diatoms appeared in Lake Mize while such forms
were common on Elk Lake slides.
In Elk Lake, a large film of debris collected on
slides submerged at the depth of 3 meters after 3 weeks.
A number of metaplanktonic and planktonic species became
associated with this debris, becoming more abundant than
the closely adhering and stalked diatoms. The layer of
debris on 6- to 30-inch slides in Lake Mize never became
as thick as that in Elk Lake. (Because most of the light
was absorbed by upper layers of the lake, slides submerged
at 3 meters in Lake Mize had a very sparse flora.) Fewer
metaplanktonic species were also associated with Lake
Mize slides in the latter stages of succession than on
the 3-meter Elk Lake slides.
VI. DISCUSSION
As could be anticipated, the species composition
and relative frequencies of organisms within the communi-
ties of attached algae in Lake Mize were dependent upon a
number of factors.
Losses Due to Peeling
Losses due to peeling from an established
periphyton community had a major influence upon the species
diversity and the relative abundance of species within the
community. Peeling — the detachment of portions of the
periphyton from a substrate — may be caused by current, by
decomposition gases (Neal, Patten, and DePoe , 1967), or by
movements of fish and other animals.
Examination of periphyton dislodged from the
substrate by slight movements in the water and of species
falling to the bottom of collecting jars indicated that
losses of individual species were not in proportion to the
relative frequencies of the species within the part of the
community left adhering to the substrate. Slightly greater
losses of the loosely associated species of the meta-
plankton occurred than of tightly appressed species. Most
of these metaplanktonic species in Lake Mize were desmids
- 16 4 -
- 165 -
which were frequently rare species in the periphyton.
Two blue-greens, Osaillatoria tenuis and Anahaena oscil-
lavioides, at times were also part of the loosely associated
metaplankton. At such times, losses by peeling were accom-
panied by substantial decreases in frequencies of these
two algae. Peeling was responsible for the frequency
decrease in 0. tenuis on glass slides between August 20
and September 11, 1969.
Peeling due to decomposition gases within the
debris or to currents was of rather irregular occurrence
on a given substrate with respect to time. Nor did
peeling take place at the same rate on replicate substrates
subjected to the same limnological conditions. This
peeling and subsequent recolonization by tightly adhering
forms on portions of the substrate undergoing peeling
sometimes caused a great deal of variation between closely
situated periphyton communities on replicate substrates.
Such variation, however, was not nearly as large as that
encountered in different seasons, at different localities
in the lake, on different substrates at a particular time,
or at different depths.
Changes with Time: Colonization and Succession
Although metaplanktonic species have a slightly
higher rate of loss from the periphyton than tightly
adhering forms , the members of a given attached species of
166 -
any form in the open waters of the lake may be presumed to
be a function of the relative abundance of the species
within the periphyton and of the turbulence in the lake at
that time. Such species when present in plankton samples
are generally referred to as tychoplankters.
Colonization of a clean substrate introduced into
the lake was initiated within hours by drifting tycho-
plankters. Most pioneer attaching species were not the
same at different seasons or during the same year. Instead,
pioneer attachers on a bare substrate were generally those
species which were the most abundant in the lake (or area
of the lake) at the time that the substrate was submerged.
After attachment to a substrate by an individual cell or
other unit of dispersal, subsequent cell divisions occurred
if environmental conditions were suitable. A scattering of
single-celled forms then developed from the original point
of attachment while filament or colony formation took place
for those forms. Microscopic examination of slides exposed
for 7 days in the upper 6 to 18 inches of the lake generally
showed considerable variation in the frequencies of attached
species which were capable of rapid divisions, e.g., diatoms,
Chance apparently dictated the numbers of such tychoplank-
ters which made contact with a clean substrate during the
first days after submergence. Subsequent rapid divisions
on a substrate to which many tychoplankters chanced to
- 167 -
attach resulted in higher frequencies of the species than
on replicate substrates where fewer tychoplankters made
contact.
Pioneering attaching species in Lake Mize were
generally either tightly adhering, resupinate forms or
filamentous and secured to the substrate by a holdfast.
With the passing of time (up to 3 to 5 weeks generally)
debris collected on the substrate. This accumulation of
debris was accompanied by an increase in the number and
frequency of metaplankters present. Metaplanktonic forms
also occurred intermingled with filamentous forms,
apparently requiring an association with either debris or
filaments if they were to be retained on a substrate
subjected to light currents.
This retention of the metaplankton was by no means
absolute. After a period of time, generally exceeding
3 to 5 weeks, the layer of debris accumulated was usually
great enough so that peeling ensued with a loss of many
members of the periphyton. Secondary succession then
proceeded to take place on cleared areas of the substrate.
Influence of the Substrate
Authorities are of divergent opinions regarding
the degree and nature of the selectivity exerted by
- 168 -
different types of substrates for various attached species
(Godward, 1937; Castenholz, 1957; Sladeckova, 1962). In
Lake Mize no absolute substrate specificity by any species
of attached algae could be observed. However, the
epiphytic communities on various macrophyte species at
the same depth in the same area of the lake were usually
significantly different. These differences existed with
both naturally growing plants and those submerged for
identical submergence periods in plastic or glass
enclosures. The macrophytes involved were apparently
exposed to the same environmental conditions so that
substrate differences would appear to be the cause of
variation in the epiphytic communities. However, if the
same macrophytic species was collected at the same
littoral station over a period of several years, the
epiphytic species which were prevalent on it in time
disappeared or sometimes appeared on another vascular
aquatic species at the same or different littoral stations.
It follows logically that the influence of the substrate
is part of a complex interaction of factors acting upon
the epiphytic communities. A few references exist in
the literature to this interaction of the substrate and
other environmental conditions. After reviewing several
papers by Pearsall (1917, 1920, 1921, 1933) on rooted
- 169 -
vegetation and the distribution of animals in English
lakes, Macan (1970) concluded that on any one type of
substrate, conditions for attachment by algae are
different in different areas of a lake.
Current and its interaction with different types
of substrates seem to be of critical importance in Lake
Mize. During August, 1970, the filamentous sedge,
Webstevia submevsa , was placed in the limnetic area of
the lake, a part of the lake which is subject to currents.
A stratified community of epiphytes with many meta-
planktonic species soon developed. Limnetic area glass
slides, however, had few metaplanktonic species and lower
overall frequencies of all attached species. In littoral
areas of the lake, the filamentous macrophytes, W. suhmersa
and Utviaulavia olivacea , were generally more densely
populated than the broader leaf blades and leaf sheaths
of other macrophytes. The greatest differences existed
when epiphytic communities on filamentous macrophytes were
compared with the periphyton of glass slides.
At least one reference has been made in the
literature stating that aquatic macrophytes with finely
divided leaves tend to be more heavily populated by many
epiphytes, including desmids, than macrophytes without
such leaves (Sculthorpe, 1967). It may be hypothesized
- 170 -
that the morphology of finely divided leaves makes for
easier attachment and/or more protection for epiphytes.
The filamentous morphology of W. suhmersa and U. oliVaoea
appears to do likewise.
Glass slides are a convenient means of studying
attached algae and are commonly used for such research.
Regarding the effectiveness of this method, the point
has been made earlier that both population density and
the number of species were lower on glass slides than on
the aquatic macrophy te , W. suhmersa , in Lake Mize. This
was the case both in the open waters of the limnetic area
and in protected enclosures in the littoral zone. However,
inside protective enclosures, the periphyton communities
of glass slides and W. suhmersa more nearly resembled
each other quantitatively and qualitatively. On littoral
area slides, frequencies of most species of both firm
attachers and metaplankters were greater than on limnetic
area slides at the same depth. Comparisons between the
attached communities on glass slides and on nonf ilamentous
macrophytes such as Sphagnum maarophyllum and Mayaaa
auhleti showed somewhat comparable frequencies of attached
algae. However, macrophytes of any morphological form
were more likely to support metaplanktonic forms and
certain species of adhering blue-greens than were glass
slides. Conversely, other blue-green species were more
likely to appear on glass.
- 171 -
Except for some inetaplanktonic desmids, all
species of attached algae which were present in Lake
Mize appeared at some time during the study on glass
slides. Both Castenholz (1967) and Sladeckova (1962)
have commented upon the relative absence of blue-greens
recovered from glass slides. In Lake Mize, blue-greens
did occur on glass slides, especially in more protected
portions of the littoral area.
During August, 1970, the blue-greens, Hapalosiphon
fontinalis (prostrate, filamentous) and Anabaena
osoillarioides (loose, filamentous), were rare and
infrequent, respectively, on glass slides submerged 6
inches in the limnetic area. In contrast, these same
species were very abundant on W. submersa submerged to a
comparable depth in the limnion of the lake. These two
blue-greens were also common to abundant on other aquatic
macrophytes during August, 1970.
While this observation tends to agree with those
of Castenholz and Sladeckova, other observations from Lake
Mize do not. Under certain conditions, blue-greens had
high frequencies on glass slides. Both H. fontinalis and
A. osoillarioides were sometimes abundant on slides
submerged at station 2. This station was located behind
a projecting arm of the shoreline which protected it from
- 172 -
north-south and south-north currents. During August,
1969, two blue-green species, Osoillatoria tenuis and
Phormidium tenue , were also coininon and very abundant,
respectively, on limnetic area slides.
It seems likely that some blue-greens, e.g.,
H. fontinalis and A. osoillarioides , are weak attachers,
especially as compared to the diatom, Eunotia. Lake Mize
is surrounded by trees which act as a wind buffer. This
added protection from the wind, which diminishes the
magnitude of currents, probably allows weakly adhering
blue-greens to attach to glass, although losses of blue-
greens from glass were higher than from most macrophytes.
In quieter areas of the lake (station 2) , even glass slides
had a diverse and abundant blue-green flora.
Influence of Physical Factors — Current
The influence of the current in Lake Mize has
already been alluded to in the discussion of substrates.
One additional observation about current should be made.
When slides were placed in an area subject to the fastest
currents (just above the outflow ditch during a time of
high water) , the slides became covered by several species
of the diatom, Eunotia, i.e., Eunotia pectinalis , E.
vanheurckia, and E. zygodon with few other algae present
(Table 33) .
- 173 -
In Lake Mize, therefore, only firmly attaching,
resupinate forms were able to remain attached to slides
in relatively fast currents, and, 95-98% of these were
diatoms. Due to the absence of filamentous and
metaplanktonic species, diversity was low.
Unlike Lake Mize, Elk Lake, Minnesota, was only
partially surrounded by trees and as such was more exposed
to wind. In Elk Lake, when slides were submerged at
meter intervals in the top 4 meters of the lake, most of
the attached species found in the upper 2 meters were
tightly adhering, resupinate forms, e.g., Achnanthes
minutissima . Surface currents presumably did not
penetrate to the depth of 3 meters where slides supported
a number of planktonic and metaplanktonic species.
Influence of Physical Factors — Light
Light was a severely limiting factor for attached
algae in Lake Mize due to the darkly colored waters. Only
in the upper 6 to 30 inches of the lake was light not
reduced to a critically low level. The degree of
huraolimnic acid coloration of the water fluctuated from
time to time, so that the vertical range of the producers
varied somewhat as a function of the amount of coloration.
The vertical range of producers also varied with different
- 174 -
substrates, extending deeper on Websteria submersa than
on glass slides. The depth of maximum algal frequencies
was also different on these 2 substrates, generally
occurring at 6 inches for glass and at 18 inches for W.
submersa. An interaction of several factors probably
accounted for these differences. Losses due to peeling
from both plants and slides were probably greatest at
6 inches due to surface currents in the lake. At all
depths, losses were presumably greater from slides than
from W. submersa. Only near the surface of the lake was
photosynthesis sufficient to maintain a rapidly increasing
algal density while also replacing losses from slides.
With fewer losses on W. submersa at 18 and 30 inches than
at 6 inches, greater population growth occurred despite
the decreased photosynthesis. In the green-colored waters
of Elk Lake, light became limiting for the attached flora
of slides only below a depth of 3 meters.
Influence of Physical Factors — Temperature
An increase in temperature in Lake Mize during
late summer and early fall was accompanied by an increase
in the frequency of Cyanophytes among the attached flora
during the 3 years of the study period. In late July or
early August, 2 Cyanophyte species generally became
- 175 -
abundant to very abundant on some substrates in the lake.
These species were not always the same from year to year.
In 1969, high frequencies were recorded for Oscillatoria
tenuis and Phormidium tenue while Anabaena osaillarioides
and Hapalosiphon fontinatis became abundant in both 1970
and 1971 during the warmer months.
Seasonal Influences
The seasonal variation in the periphyton of Lake
Mize was not as great as that reported for lakes in the
state of Washington (Castenholz, 1967) or for plankton
(Fogg, 1966), Other than the influence of high
temperatures associated with summer and fall, the effect
of wind and storms seemed to be the chief seasonally
related factor influencing the diversity and abundance of
the attached algae. Slides placed in the limnetic area
of the lake during the comparatively calm 1968-19 69 winter
season had a flora characterized by a number of species of
metaplanktonic desmids and by high frequencies (abundant)
of filamentous greens. Slides placed in the limnetic area
during the periods August to September, 1969, and July to
August, 197 0, when the lake's waters were occasionally
turbulent from the action of summer storms, had a flora
dominated by tightly adhering, resupinate forms. Few
filamentous or metaplanktonic forms were present.
- 176 -
An exception was Osoillatoria tenuis which in August,
1969, was common on limnetic area slides. Large losses
from slides of this alga occurred between August 20 and
September 11. In July, 1970, similar losses from slides
of the metaplanktonic Gleooystis vesioulosa also occurred.
At these times, summer thunderstorms were common and
probably accounted for the large losses of algae from
slides.
Conversely, many filamentous and metaplanktonic
forms were abundant in some areas of the littoral zone
during the summer and fall months where waters were
presumably calmer and the area more protected. There the
periphyton persisted through turbulent periods caused
by rains and wind. This relatively restricted occurrence
and frequent losses of filamentous and metaplanktonic
forms during the summer and fall seasons may be contrasted
with the winter season when such forms were widespread in
all parts of the lake. Losses during December, January,
and February (1968-1969) were also minimal.
A number of algal species were sporadically
abundant in the periphyton of Lake Mize. Except for
warmer summer and fall months, one or more Chlorophytes
were dominant components of the periphyton. However, the
pulses of individual species could not be predicted as to
- 177 -
month or season. The occurrence of particular species
in the periphyton during the December, 1968, to September,
1971, was noncyclic.
VII. SUMMARY
A floristic survey from December, 1968, to
September, 1971, provided a record of the communities of
attached algae in Lake Mize, Florida. Eighty-nine algal
species were identified and monitored during the study
period. Thirteen other unidentified species were also
present. Of the 102 species distinguished, 63 were
Chlorophytes, 2 were Euglenophytes, 22 were Chrysophytes ,
2 were Pyrrophytes, 11 were Cyanophytes, 1 was a Xantho-
phyte, and 1 was a Chloromonadophyte. Both quantitatively
and qualitatively, desmids and filamentous Chlorophytes
were usually an important part of the periphyton in Lake
Mize. Several acidiophilic diatoms were abundant at
certain times while Cyanophytes generally reached high
frequencies only during the July to September period.
Counts and estimates were used to determine the
relative abundance and frequencies of the species present
under different environmental conditions. Such analyses
indicated that at any given time, and place, a number of
factors influenced the composition of the periphyton.
The most important conclusions drawn from this study
regarding the influence of certain seasonal and environ-
mental factors upon the phyco-periphyton are:
- 178 -
- 179 -
Algae employing particular modes of attachment
were more abundant under some conditions than
in others. Generally, tightly adhering,
resupinate forms attained higher densities on
glass slides than filamentous and loosely
associated metaplanktonic species. Conversely,
the epiphytic flora of the filamentous sedge,
Websteria submersa, contained a large number of
both strong and weak attachers. Substrates
of any type exposed to a moderate current were
populated almost exclusively by tightly adhering,
resupinate forms.
At any given time, different areas of the lake
supported somewhat different periphyton
communities. In calmer areas of the lake or in
protected enclosures, metaplanktonic and
filamentous species were more abundant on all
substrates than in areas subjected to currents
and turbulence.
Light was an important environmental factor in
determining the taxonomic composition of the
periphyton community, Chlorophytes were
generally abundant only in the upper 6 to 18
inches of the lake. Attached Chrysophytes had
a broader vertical range, frequently remaining
common to a depth of 30 inches on glass and 42
inches on Websteria submersa. Light requirements
for Cyanophytes were variable with some species
restricted to the upper 6 to 18 inches of the
lake and other remaining common to a depth of 42
inches .
Seasonal influences upon the attached algae of
Lake Mize were not as pronounced as those
reported for northern lakes. During the study
period pulses of individual species occurred
in the periphyton but their occurrence could not
be predicted as to month or season. Desmids
and filamentous Chlorophytes were generally
abundant throughout the year while maximum
frequencies of Cyanophytes occurred during the
warmer summer and fall months. The lack of
turbulence from winds and storms during the
winter season also influenced the periphyton,
permitting metaplanktonic and filamentous
species to become widespread in the lake.
- 180 -
When clean substrates (slides or plants) were
submerged in the lake, the pioneering attachers
were usually the most abundant resupinate and/
or filamentous forms in the lake at the time.
With time, frequencies of the early attachers
increased. Under proper conditions, species
diversity also increased as metaplanktonic forms
became associated with the substrate. Peeling
and a loss of metaplanktonic and other attached
species generally occurred with exposure periods
exceeding 3 to 5 weeks or under conditions of
sudden turbulence, e.g., storms.
The attached flora of the dystrophic Lake Mize,
Florida, was very unlike that of the mesotrophic
Elk Lake, Minnesota. Whereas Chlorophytes were
the most important component of the periphyton
in Lake Mize, diatoms formed the majority of
the attached flora in Elk Lake.
APPENDIX
- 182 -
TABLE 38
Master List of the Attached Algae of Lake Mize, Florida,
and Planktonic Species Associated with Communities of
Attached Algae, December, 1968, to September, 1971
Chlorophyta
Volvocales
Eudorina elegans Ehrenberg*
Tetrasporales
Gleoaystis vesiculosa Naegeli
Ulotrichales
MioTospora tumidula Hazen
Miorospora pachyderma (Wille) Lagerheim
Protoderma viride Kutzing
Aphanoohaete repens A. Braun
Helioodiatyon planatonioum (Whit.) Whitford &
Schumacher*
Coleochaete irregularis Pringsheim.
Diaranoohaete reniformis Hieronymus
Oedogoniales
Oedogonium reinschii Roy
Oedogonium spp.
Bulboohaete spp.
Chlorococcales
Charaoium amhiouum Hermann.
Schoederia setigera (Schroed.) Lemmermann
Coelastrum sphaerioum Nageli
Ankistrodesmus falcatus (Corda.) Ralfs
Soenedesmus dimorphus (Turp. ) Kutzing.
Zygnematales
Spirogyra spp.
Mougeotia spp.
Spirotaenia condensata Breb.
Netrium digitus (Ehren.) Itzigsohn and Rothe
- 183 -
TABLE 38 — Continued
Closterium incurvum Brebisson
Closterium intermedium Ralfs
Closterium libellula Focks
Closterium navicula (Breb.) Lutkem.
Closterium setaceum Ehrenberg
Pleurotaenium minutum (Ralfs) Delponte
Pleurotaenium subcoronulatum var . detum (Turner)
West & West
Triploaeras gracile Bailey
Tetmemorus brebissonii (Menegh. ) Ralfs
Euastrum affine Ralfs
Euastrum binale (Turp. ) Ehrenberg
Euastrum ciastonii Racib.
Micrasterias fimbriata Ralfs
Aatinotaenium cruoiferum (De Bary) Telling
Cosmarium amoenum Ralfs
Cosmarium bireme Nordstedt
Cosmarium blytii Wille
Cosmarium ornatum Ralfs
Cosmarium pygaeum Archer
Cosmarium pyramidatum Brebisson
Cosmarium regnellii var. pseudoregnellii
(Messikommer) Krieger & Gerloff
Arthrodesmus incus (Breb.) Hassall
Arthrodesmus octoaornis Ehrenberg
Xanthidium antilopaeum var. minneapoliense Wolle
Xanthidium subhastiferum var. towerii (Cushman)
G. M. Smith
Staurastrum leotocladum Nordstedt
Staurastrum paradoxum Meyen
Staurastrum pyramidatum West
Staurastrum spp.
Onahyonema taeve var. latum West & West
Hyalotheaa undulata Nordstedt
Hyalotheaa dissiliens (Smith) Brebisson
Desmidium baileyi (Ralfs) Norstedt
Bambusiana brebissonii Kutzing
Spondylosium pulahellum var. bambusinoides (Wittr.)
Lundell
Euglenophyta
Euglena sp.
Phaous lemmermannii ($wkr. ) Skvortzow
- 184 -
TABLE 38 — Continued
Xanthophyta
Stephanoporos regularis (Pasch.) Bourrelly
Chrysophyta
Chrysophyceae
Dinobryon bavaricum Imhof
Binobryon oalci forme (Bachmann) Hilliard & Asmund
Dinobryon cylindricum Imhof*
Dinobryon euryostoma (Leram. ) Hilliard & Asmund
Mallomonas oaudata Conrad*
Mallomonas sp*
Synura sphagniaola Korsch*
Lagynion scherffellii Pascher
Ehipidodendron splendidum Stein
Bacillariophyceae
Asterionella formosa Hassal.*
Eunotia ourvata (Kutz.) Lagerheim
Eunotia pectinalis (Kutz.) Rabenhorst
Eunotia vanheurokia var . intermedia (Kras. ex. Hust. )
Patrick
Eunotia zygodon Ehrenberg
Frustulia rhomboides var. saxoniaa (Rabh. ) de Toni
Neidium ladogense var. dens estriatum (Oestrup) Foged
Navicula minima Grunow
Gomphonema lanoeotatum Ehrenberg
Nitsahia patea (Kutz.) W. Smith
Surirella biseriata var. constriata Grunow
Surirella robusta var. splendica (Ehr.) Van Heurck.
Pinnularia gibba Ehrenberg
Pyrrophyta
Peridinium limbatum (Stokes) Lemmermann*
Peridinium westii Lemmermann*
Chloromonadophyta
Gonyostomum semen (Ehr.) Diesing.*
- 185 -
TABLE 38 — Continued
Cyanophyta
Chroococcales
Aphanoaapsa delioatissima West & West
Oscillatoriales
Osaillatoria tenuis Ag .
Phormidium angustissimum West & West & West
Phormidium tenue (Meneg.) Gomont
Lynhya nordgaardii Wille
Anabaena osoillavioides Bory
Anabaena variabilis Kuetzing
Anabaena lapponica Borge
Anabaena flos- aquae (Lyngh.) Brebisson*
Hapalosiphon fontinalis (Ag.) Bornet.
Calothrix epiphytiaa West & West
*Planktonic species.
Figure 17. Germlings of Bulhoahaete sp. on Wehsteria
submevsa (x400) , Lake Mize.
Figure 18. Colony of Protoderma viride , a prostrate
Chlorophyte , with diatoms, Nitsahia palea and
F.rustulia rhomboides (xl,400). Lake Mize.
Figure 19. Osoillatovia tenuis filaments (xl,300),
Lake Mize.
Figure 20. Anabaena osoillavioides (xl,000), Lake
Mize.
- 187 -
Figure 21. Closterium setaceum (x320) , Lake Mize.
Figure 22. Closterium naviaula (x600) , Lake Mize.
Figure 23. Oedogonium sp. , showing holdfast (x400) ,
Lake Mize.
Figure 24. Branched filaments of Hapalosiphon
fontinalis (x500) , Lake Mize.
- 189 -
Figure 21
Figure 22
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w
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m
. .T-^^
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I^K_*!iA.
. • >r- •
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Figure 23
Figure 24
Figure 25. Portion of the attached coimnunity of a
glass slide, showing Cosmarium vegnellii
Eunotia sp. , and a filamentous Oomycete (x600) ,
Lake Mize.
Figure 26. Frustulia rhomhoides var. saxonica
(x750) , Lake Mize.
Figure 27. Rhipidodendron splendidum , a heterotrophic
Chrysophyte (x300) , Lake Mize.
Figure 28. Epithemia zebra {x400) , Elk Lake.
- 191 -
Figure 26
Figure 27
Figure 28
- 192 -
TABLE 39
Master List of the Attached Algae and Planktonic
Species Associated with Attached Algae in
Elk Lake, Minnesota, August, 1967
Chlorophyta
Ulotrichales
Protoderma viride Kutzing
Coleoohaete orbicularis Pringsheim
Chlorococcales
RadiocoGcus nimbatus (de Wild.) Schmidle
Ooaystis sp.
Oedogoniales
Oedogonium sp.
Bulbochaete sp.
Zygnematales
Mougeotia sp.
Spirogyra sp.
Euglenophyta
Euglena sp.
Chrysophyta
Bacillariophyceae
Cyctotella bodin var. affinis 0. Mull.
Tabellaria flocculosa (Roth.) Kutzing.
Synedra radians Kutzing.
Synedra ulna (Nitz.) Ehrenberg
Synedra aatinastroides Lemmerman
Achnanthes minutissima Kutzing
CooQoneis placentula Ehrenberg
Amplipleura pelluoida Kutzing
Gomphonema lanoeolatum Ehrenberg
Gomphonema acuminatum var. coronata (ehr.) W. Smith
- 193 -
TABLE 39 — Continued
Gomphonema intriaatum var. pumila Grun.
Amphora ovalis Kutzing.
Cymhella affinis Kutzing
Cymhella cistula (Hemprich) Grun.
Epithemia turgida (Ehr. ) Kutzing
Epithemia zebra (Ehr.) Kutzing
Rhopalodia gibbia (Ehr.) 0. Muller*
Nitsahia palea (Kutz.) W. Smith
Nitschia gracilis Hantzsch.
Cyanophyta
Chroococcales
Merismopedia sp.
Coelosphaerium sp.
Gomphospaeria aponina Kutzing
Gomphospaeria laaustris Chordat*
Osc ilia tor iales
Osaillatoria quadripunatulata Bruhl & Biswas
Lyngbya sp.
Spirutina sp.
*Planktonic species.
- 194 -
TABLE 4 0
The Algal Flora Present on Vertically Positioned Glass
Slides Suspended in the Limnetic Zone of Lake Mize
during January, 1969; August, 19 69; and
August, 19 70 (VA = Very abundant,
A = Abundant , C = Common , I =
Infrequent, R = Rare)
January August August
1969 1969 1970
Chlorophyta
Protoderma viride
Kutzing
Coleoahaete irregularis
Pringsheim
Ankistrodesmus fatcatus
(Corda.) Ralfs
Heticodiotyon
ptanatonicum
Oedogonium spp.
Bulboohaete sp.
Spirogyra spp.
Mougeotia spp.
Closterium setaaeum
Ehrenberg
Closterium intermedium
Ralfs
Closterium navicula
(Breb. ) Lutkem.
Pteurotaenium subcoronu-
latum var. detum
(Turner) W. & G. S.
West
Triploaerus graoile
Bailey
Euastrum affine Ralfs
R
R
R
R
R
R
I
R
I
I
R
R
R
R
A
R
R
P
R
R
R
R
R
- 195 -
TABLE 40 — Continued
January August August
1969 1969 1970
Euastrum oiastonii
Racib. R
Euastrum binale (Turp. )
Ehrenb.
Micrasterias fimbriata
Ralfs R
Cosmarium amoenum Ralfs R
Cosmavium ornatum Ralfs R R
Cosmarium regnellii var.
psuedoregneltii
(Messikoinmer) Krieger
& Gerloff R I
Cosmarium pygmaeum
Archer R
Cosmarium hireme Nordstedt R A R
Cosmarium pyramidatum
Breb.
Xanthidium antilopaeum
var. minneapoliense
Wolle R
Staurastrum leptoaladum
Nordstedt.
Staurastrum gladiosum
Turner R
Staurastrum orbiaulare
Ralfs
Staurastrum paradoxum
Meyen R R
Staurastrum sp. 1 R
Staurastrum sp. 2 R
Arthrodesmus incus
(Breb.) Hassall R
196 -
TABLE 40 — Continued
January August August
1969 1969 1970
Avthvodesmus octocovnis
Ehrenberg R
Hyalotheaa dissiliens
(Smith) Brebisson R
Hyalotheaa undutata
Nordst. R
Desmidium haileyi
(Ralfs) Nordstedt. R
Chrysophyta
Dinobryon calciforme
(Bachmann) Hilliard
& Asmund I
Dinobryon eury stoma
(Lemm. ) Hilliard
& Asmund R
Mallomonas aaudata
Conrad R I
Rhipidodendron sptendidum
Stein I
Eunotia curvata (Kutz.)
Lagerheim I
Eunotia peatinatis
(Kutz.) Rabenhorst I A C
Eunotia vanheruckia var .
intermedia (Krasske
ex. Hustedt) Patrick
Frustulia rhomboides var.
saxonioa (Rabh. ) de
Toni I R R
Neidium ladogense var.
densestriatum (Oestrup)
Foged R R
- 197
TABLE 40 — Continued
January August August
1969 1969 1970
Pyrrophyta
Cyanophyta
Naviaula minima Grunow. R C
Gomphonema lanaeotatum
Ehrenberg C
Nitssahia palea (Kutz.)
W. Smith I C
Surirella biseviata var.
aonstricta Grunow. R
Asterionella formasa va.i:.
graaillima (Hantz.)
Grunow. R
Peridinium limhatum
(Stokes) Lemmermann R
Peridinium westii
Lemmermann R
Anacy stis marina
Crouet & Daily A
Osailtatoria tenuis Ag. A
Phormidium angustissimum
West & West I
Phormidium tenue
(Menegh.) Gomont I VA
Phormidium tenue
(Meneg.) Gomont R R
Anabaena Osoillarioides
Boay R I
Hapalosiphon fontinalis
(Ag. ) Hornet. R
Calothrix epiphytiaa
West & West R
- 198 -
TABLE 40-
'^ontinued
January
1969
August
1969
August
1970
Euglenophyta
Euglena sp.
Total Number of Species
VA
40
27
15
Note: Frequencies given here represent the maximum
population occurring on glass slides placed in the
limnetic zone of Lake Mize. This maximum frequency may
have occurred on slides at any of the following levels:
6 inches, 18 inches, 30 inches, or 42 inches. Depending
upon the species, cells, filaments, or colonies may have
been counted.
Very Abundant (VA) represents a frequency of over 5,000
per square centimeter.
Abundant (A) represents a frequency of 2,000 to 5,000 per
square centimeter.
Common (C) represents a frequency of 500 to 2,000 per
square centimeter.
Infrequent (I) represents a frequency of 100 to 500 per
square centimeter.
Rare (R) represents a frequency of 10 to 100 per square
centimeter.
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BIOGRAPHICAL SKETCH
Helen Davis Brown was born in Charlotte, North
Carolina, on March 23, 1934. She graduated from North
Mecklenberg High School in 1952. Her undergraduate
eduation was obtained at Mars Hill Junior College
(A.A. , 1954) and Appalachian State Teachers College
(B.S., 1956). The M.A. degree was also awarded her in
1959 by Appalachian State Teachers College after study
during successive summers from 1957 to 1959. During the
19 66-19 67 academic year, graduate study in botany was
begun at the University of Minnesota. A doctoral
program in botany with a specialization in phycology
was then initiated at the University of Florida in 1967,
continuing through 1972.
As a teacher in secondary schools prior to the
majority of her graduate work, Helen Davis Brown
held the following positions: Arlington Junior High,
Gastonia, North Carolina (1956-1962) ; Woodbridge Junior
High, RAF Woodbridge, England (1962-1964); and DeLaura
Junior High, Satellite Beach, Florida (1964-1966).
While at the University of Florida, she held a
graduate assistantship from the Botany Department during
the years 1967-1968 and 1971-1972 and a Graduate School
- 204 -
- 205 -
Fellowship during the 1968-1969 academic year. From 1969-
1971 she also served in an interim appointment as an
assistant professor of biology at Augusta College in
Augusta, Georgia.
I certify that I have read this study and that in
my opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality,
as a dissertation for the degree of Doctor of Philosophy.
'i^
^L
a:il. Chairman
D/. Dana G. Gri'jniin,
Assistant Professor of Botany
I certify that I have read this study and that in
my opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality,
as a dissertation for the degree of Doctor of Philosophy.
Dr. Leland Shanor
Professor and Chairman, Botany
I certify that I have read this study and that in
my opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality,
as a dissertation for the degree of Doctor of Philosophy.
Hemry C. Aldrich
Dr.
Associate Professor of Botany
I certify that I have read this study and that in
my opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality,
as a dissertation for the degree of Doctor of Philosophy.
Dr. yJames'lW. Kimbroughy
As^ciate /Prof essor or Botany
I certify that I have read this study and that in
my opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality,
as a dissertation for the degree of Doctor of Philosophy.
)r. Frank G. Nordlie
Associate Professor Zoology
This dissertation was submitted to the Dean of the College
of Agriculture and to the Graduate Council, and was
accepted as partial fulfillment of the requirements for
the degree of Doctor of Philosophy.
August, 1972
of Agriculture
Dean, Graduate School
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