Newsletter

Volume 9, Number 2
March - April 1992

Director’s Note

While much of the Institute’s research is
done at long-term sites at the Mary
Flagler Cary Arboretum, field work and
collaborative studies are done at many
other sites as well, locally, regionally and
globally. Field sites in the Adirondack
Mountains have been especially impor-
tant in our long-term studies of lake
acidification.

Dr. Paul Bukaveckas, a post-doctoral
scientist at the Institute for the past two-
and-a-half years, is investigating the
effects of acid precipitation in the
Adirondack Mountain region from a
number of perspectives, and also is
testing ways in which lake acidification
might be controlled. Several of his on-
going studies are described in this issue
of the IBS Newsletter.

The IBS Newsletter is published by the
Institute of Ecosystem Studies at the
Mary Flagler Cary Arboretum. Located
in Millbrook, New York, the Institute is a
division of The New York Botanical
Garden. All newsletter correspondence
should be addressed to the Editor.

Gene E. Likens, Director
Joseph S. Warner, Administrator
Alan R. Berkowitz, Head of Education

Editor: Jill Cadwallader
Printing: Central Press

INSTITUTE OF ECOSYSTEM
STUDIES

The New York Botanical Garden
Mary Flagler Cary Arboretum
Education Program
Box R

Millbrook, NY 12545
(914) 677-5359

Acid Rain and Adirondack Lakes

New York state, with the boundaries
of the Adirondack Park
(celebrating its
centennial this year).

Lake

Placid

Dr. Bukaveckas’ principal
research sites: a) Little Simon Pond;
b) Woods Lake; c) Cranberry Pond; and
d) Dart's Lake. Lake Placid, site of the 1980
winter Olympic Games, is shown for reference.

What’s special about the
Adirondack Park? For
starters, it’s as large as
its neighbor across Lake
Champlain: the state of
Vermont. With 24,000
square kilometers (9,250
square miles) of land, it
is the largest park in the
lower 48 states. It
comprises both publicly
owned property and
private lots, distinguish-
ing it from the wholly
government-owned
national parks. Its
approximately 130,000
year-round residents and
those who maintain
vacation homes there share the park lands
with animals and plants representing 90%
of the species that live in the Northeast. It
is a true wilderness, with mountains, mixed
forests ... and a lot of water: 48,300 km
(30,000 mi) of brooks and streams, 2,400
km (1,500 mi.) of rivers, and over 2,800
lakes and ponds including the source of the
Hudson River, Lake Tear of the Clouds.

The Adirondack Park is unique in another
way as well: together with the Catskill
Mountains to its south, it receives more
acidity from precipitation than anywhere
else in the United States. This is because
the mountain chain is the first elevated land
mass in the path of prevailing winds from
the Ohio River Valley, a heavily industrial-
ized and urbanized region that releases
high levels of sulfur and nitrogen gases'.

As air currents move east they rise up the
mountain slopes and become cooled;
precipitation is the result, and the chemi-
cals in the atmosphere make that precipita-
tion acidic.

The Adirondack Mountains are largely
granite. Had they been limestone, the high
levels of acid deposition perhaps would be
buffered to a more normal leveF. Granite,
however, has little capacity to neutralize
acids, and this, coupled with the high

' Sulfur and nitrogen oxides released to the
atmosphere react chemically with water
molecules to produce sulfuric and nitric acids,
leading to “acid rain’’ and other forms of acid
precipitation. The acidity of precipitation is
measured on a logarithmic pH scale. On the
scale of 0 to 14 with neutral at 7.0, very acidic
compounds are at the low end of the scale
(lemon juice has a pH of approximately 2 and
vinegar of 3) and very basic compounds are at
the high end (ammonia: pH 11; lime: pH 12;
lye: pH 13). The pH of acid rain is generally in
the 2.0 - 5.0 range, while that of “normal’’ rain
is 5.2 or higher.

levels of acidity in the rainfall and the large
number of lakes in the area, made the
effects of air pollution particularly evident
in the park.

The conspicuous changes in the lakes of
the Adirondack Park are similar to those
observed in acidified lakes in Canada and
Europe. First, levels of trace metals in the
lake water are several times higher than
those measured in non-acidic lakes. Levels
of aluminum, a natural component of soils,
are especially high because the acidic
rainwater dissolves aluminum and carries it
from the soil into the lakes. This, then,
leads to the second and most visually
apparent change: the lakes become clear.
In lakes unaffected by acid precipitation,
compounds dissolved in the water absorb
light and give the water a degree of color.
In acidified lakes, however, aluminum
binds these dissolved compounds and they
sink to the bottom.

Finally, there is a major loss of biodiversity
at all levels of the food web, from phyto-
plankton and zooplankton up to higher
plants, amphibians and fish. A non-acidic
Adirondack lake, for example, may contain
from 30 to 60 different kinds of phyto-
plankton, while an acidified lake has only
from 10 to 15. Of the fish communities,
always of limited diversity in lakes, brook
trout and other popular sport fish are
especially sensitive to acidification, and
there are a number of lakes within the
Adirondack Park that are so acidic they
support no fish at all. What is it about acid
rain that is especially harmful to living
organisms? This effect is not understood
fully, but it is believed that the changes in

continued on page 2

^ Limestone, or calcium carbonate, reacts with
sulfuric acid and nitric acid molecules, thereby
buffering the acidity to a more neutral pH.

Adirondack Lakes, from page 1

pH of the water may be less detrimental
than the elevated levels of dissolved
aluminum. It is known that aluminum
suffocates some species of fish by irritating
their gills.

Of the approximately 2,500 lakes in the
Adirondack Park that are four hectares (10
acres) or larger in size, approximately 10%
are severely acidified. The pH of these
lakes, historically in the 5.5 to 6.5 range, is
now between 4.5 and 5.0. These lakes are
usually surrounded by shallow soils, where
rainwater percolates quickly with little time
for its acidity to be neutralized. Those
lakes whose pH has remained above 5.5
owe their condition to the local geology:
they are surrounded by deep soils, espe-
cially soils containing limestone. There,
percolation of rainwater and snowmelt
occurs slowly and allows time for buffering
to occur.

lES Research in the Adirondacks

Dr. Paul A. Bukaveckas came to the
Institute of Ecosystem Studies in January
1 990 as a post-doctoral scientist with a
long-standing involvement in acid rain
research. His doctoral research at Indiana
University concerned the effects of acid
rain on Adirondack lakes, and he was
interested in linking his data with those
collected by lES director Dr. Gene E.

Likens at the Hubbard Brook Experimental
Forest in New Hampshire’s White
Mountains^

Dr. Bukaveckas has continued his research
on Adirondack lakes to learn how acid
rain-induced changes in the structure of the
lake ecosystem (the numbers of species
and/or the numbers of individuals within
these species) might affect the functioning
of the ecosystem, such as the interactions
between species. Dr. Bukaveckas’
research focuses on phytoplankton, the
microscopic, free-floating plants compris-
ing the base of the lake food web. Lake
acidification results in fewer species of
phytoplankton and zooplankton. Current
research is focusing on how this change in
biodiversity affects the efficiency with
which food energy is passed from the base
of the food web (phytoplankton) to the
grazer community (zooplankton) and to
higher levels in the food web.

^ The Hubbard Brook Ecosystem Study (HBES),
in existence since 1963, is at the forefront of
long-term ecosystem research. In the early
1970s, as a result of their initial HBES
measurements of ecosystem interactions. Dr.
Likens and colleagues documented the existence
of acid rain in North America.

Lake Liming Experiment

To learn more about how organisms
respond to changes in lake acidity. Dr.
Bukaveckas participated in a study in
which the pH of three acidic Adirondack
Lakes was raised by adding limestone'^.

A fourth site, Dart’s Lake, was used as a
reference lake and received no treatments.
The three experimental lakes - Little
Simon Pond, Woods Lake and Cranberry
Pond — were treated with crushed lime-
stone dumped by helicopter. At Woods
Lake and Little Simon Pond, the limestone
treatments were repeated three times in
order to maintain the desired pH during the
course of the eight-year study.

The results reveal a decrease in the amount
of trace metals in the limed lakes, and a
decrease in water transpar-
ency. In the lakes that had
been limed the ecosystem
structure changed back to
what would be considered
“normal” in unacidified
lakes, with increased
numbers of species. The
time that it took for the
organisms to respond to the
improvements in water
quality depended on the
types of organisms.

Phytoplankton recovered in
four weeks, zooplankton in
four months and aquatic
plants in two to four years.

Brook trout were stocked
and grew rapidly, but did
not spawn successfully
because the tributary
streams where spawning
would occur remained too
acidic.

Phytoplankton and Zooplankton

Dr. Bukaveckas’ research showed that lake
liming resulted in an increase in phyto-
plankton abundance. He speculated that
this increase was due to the decline of the
grazer community (zooplankton) following
the reintroduction of brook trout, which
feed on zooplankton. For this to be the
case, zooplankton must be important
potential grazers in acidic lakes. To test
this idea he selected 14 lakes with a range
of pH values and set up a simple experi-
ment: lake water, with the zooplankton
strained out, was kept for two days in
plastic containers submerged in the lake (in

'* Collaborators were from Syracuse Univ.,
Cornell Univ., Clarkson Univ., Indiana Univ.
and the U.S. Geological Survey (USGS)

order to provide conditions as near as
possible to the norm). He then compared
changes in phytoplankton abundance in
containers with and without zooplankton.
The difference represented what would
have been eaten if the zooplankton had
been present. He found that the effects of
removing zooplankton were similar in both
non-acidic and acidified lakes, suggesting
that zooplankton grazing was not affected
by changes in lake acidity.

Dr. Bukaveckas’ next question dealt with
the zooplankton community itself, and how
these organisms responded to changes in
lake acidity. He was particularly interested
in the group of species belonging to the
genus Daphnia, crustaceans barely visible
to the naked eye and commonly called
water fleas. Daphnia are very sensitive to

even slight increases in lake acidity and
also exhibit the highest grazing rates
among the many types of zooplankton. On
the other hand, copepods — crustaceans far
smaller than Daphnia — can survive in
acidified lakes but tend to have lower
grazing rates. In order to understand
differences in zooplankton grazing in
different Adirondack lakes. Dr.

Bukaveckas needed to learn more about the
species that occurred in his study lakes.

At this point he began what has become a
continuing collaboration with Dr. William
H. Shaw of Sullivan County Community
College (see following article). As the
1991 Cary Summer Fellow, Dr. Shaw
examined zooplankton samples under a
microscope to identify the species occur-
ring at each site. Dr. Shaw found differ-
ences in species composition related to

continued on following page

Drs. Paul Bukaveckas (r.) and William Shaw are collaborators in a
study of plankton communities in Adirondack lakes.

Adirondack Lakes, continued

differences in lake acidity. In non-
acidified lakes, the zooplankton were
larger in size and more diverse, while acid
lakes had smaller individuals and only
three or four species. Since Dr.

Bukaveckas already had determined that
the amount of grazing is independent of
lake pH, it was apparent that the smaller
zooplankton had as great an impact on
phytoplankton as did the larger zooplank-
ton. This surprising result has added to the
basic understanding of how lake ecosys-
tems work.

The Future of Lake Liming

Is liming an effective way of restoring
acidified lakes? It is certainly a successful
management technique for improving
water quality and restoring biodiversity.
However, as more acid rain falls the lakes
reacidify quickly, and the repeated
treatments required to maintain a more
normal pH can present their own negative
side effects.

In an effort to find another solution. Dr.
Bukaveckas and his colleagues are
studying the utility of liming watershed
soils. Limestone pellets, dispersed by
helicopter over the forested areas surround-
ing a lake, may provide a longer-term
source of buffering. Early data from
Woods Lake suggest that the effects of
watershed liming on the lake ecosystem
were comparable to those observed
following direct lake treatment, and that
watershed liming could reduce the
frequency of treatment. An additional
benefit was the improvement in water
quality of tributary streams, permitting
successful spawning by brook trout.

Early in May, Dr. Bukaveckas began a
summer of field work in the Adirondack
Park and at Hubbard Brook. His work is
supported by grants from the U.S. Fish and
Wildlife Service and the Andrew W.
Mellon Foundation.

Profile: William H. Shaw

In January 1991, Dr. William Shaw
attended a dinner meeting of the Mid-
Hudson Biologists held at the Institute’s
Plant Science Building. With a long-
standing interest in freshwater ecology, he
had come to hear Dr. David Strayer speak
about his zebra mussel research. Dr. Shaw
picked up a schedule of Institute Sunday
Ecology Programs from the information
table, noted with interest an upcoming talk
by lES Director Dr. Gene E. Likens on
“Human Accelerated Environmental
Change”, and attended the program. At the

end of his presentation Dr. Likens invited
anyone interested in current research in the
Adirondack Mountains to talk with Dr.
Paul Bukaveckas. When Dr. Shaw took
Dr. Likens up on his invitation, he had no
idea how the direction of his work would
be changed.

Dr. William H. Shaw has been a professor
of Natural Sciences at Sullivan County
Community College in Loch Sheldrake,
N.Y. since 1969. As a full-time teacher.
Dr. Shaw was limited to doing research
that could be done in the basement of his
home, during evenings and weekends.
When he spoke with Dr. Bukaveckas that
Sunday afternoon, the subject of phyto-
plankton-zooplankton interactions proved

to be one of mutual interest. Dr.
Bukaveckas was at the stage in his
research (see preceding article) where he
needed someone to examine zooplankton
samples collected from Adirondack lakes.
The collaboration was informal at first, and
then Dr. Shaw learned of the research
opportunities provided by Cary Summer
Research Fellowships.

Cary Summer Research Fellowships are
awarded by the Institute to scientists who
typically have heavy teaching responsibili-
ties but want the opportunity to do
research. Funds are provided by the Mary
Flagler Cary Charitable Trust. Dr. Shaw

continued on page 4

Volunteer Recognition Ceremony: “Volunteer support [at the Institute of Ecosystem
Studies] is of the utmost importance,” began director Dr. Gene E. Likens, adding that
the Institute’s external review committee has evaluated the lES Volunteer Program as
“outstanding”. Dr. Likens’ remarks welcomed 65 volunteers, staff and friends to the
April 23 ceremony — the largest yet, thanks in part to the program reorganization and
new recruitment policies by volunteer coordinator Su Marcy. After a catered dinner, the
guests learned from Dr. Likens of recent advances in research and education programs
and in the display gardens, and enjoyed a slide presentation by Dr. Paul Bukaveckas
about his lake-liming research in the Adirondack Park (see the story on page 1).

Su Marcy reported that during the past year lES volunteers ranging in age from 9 to 82
contributed just over 3,288 hours of their time to the greenhouse, display gardens,
laboratory and field programs, library, ecology education, gift shop and other areas.
Certificates were awarded, and all volunteers who have worked more than 10 hours
were presented with an enamel volunteer pin.

Several volunteers received special mention for their long and dedicated service. Betty
Stratton (field laboratory, greenhouse. Education Program), was recognized for the
assistance she has been giving since 1975. Hilda Messner (Gift Shop), Sally O’Brien
(Education Program) and David Smith (Security) have accumulated the greatest number
of hours, with 1,030, 1,750 and 2,442 respectively. In recognition of and appreciation
for their contributions, Hilda Messner and Sally O’Brien each received an engraved
pewter picture frame. (David Smith was unable to attend the ceremony, and his
achievement will be recognized at another time.)

Those interested in learning about lES volunteer opportunities are invited to contact
Su Marcy at the Education Program office.

From left: Su Marcy, Hilda Messner, lES head of education Dr. Alan R. Berkowitz, Sally O'Brien
and Dr. Gene E. Likens

Profile, from page 3

Summer Calendar

applied and was selected to be the 1991
Cary Fellow, enabling him to work with
Dr. Bukaveckas throughout the summer.

In addition to examining zooplankton
samples at the Institute’s microscope
facility, Dr. Shaw participated in a field
study with Dr. Bukaveckas in the
Adirondack Mountains. They compared
plankton communities among lakes that
differed in their water quality characteris-
tics. Their study sites included closed
basin lakes that are dependent upon
groundwater inputs and rainfall, and
headwater lakes that receive water from
inflowing streams and are drained by outlet
streams. Through this work the scientists
hope to learn more about how water
entering from different sources can
influence lake ecology. (Results are
summarized in the 5th edition of Discover-
ies in Ecology, soon available at the IBS
Education Program office.)

With much work still to do. Dr. Shaw was
able to arrange for laboratory space at the
Institute to continue his zooplankton
studies. He is now interested in expanding
his research to study predator and prey
interactions with a view toward under-
standing how lake acidification affects
species interactions within the plankton
community.

Dr. Shaw recently was presented with the
Chancellor’ s Award for Excellence in
Teaching for 1992. This award is made
through the office of the chancellor of the
State University of New York system. Dr.
Shaw is only the fifth professor at Sullivan
County Community College ever to have
received this honor.

INSTITUTE OF
ECOSYSTEM STUDIES

The New York Botanical Carden
Mary Flagler Caiy Ai'boretum
Education Program
BoxR

Millbrook, New York 12545-0178

Newsletter

CONTINUING EDUCATION PROGRAM
Summer Semester

June 20: The Joy of Roses

June 22, 23, 24: Basic Residential Landscape

Design

June 27: Field Course: Ferns of the North-
east

July 11 (1st of 4 Saturdays): Field Course:

Experiments in Plant Ecology

July 15: Summer and Autumn Wildflower

Gardening

July 18: Organic Lawn Care
July 27-3 1 : Illustrating Nature Outdoors
July 27-31: Colored Pencil Workshop
July 25,26: Introduction to Landscape and
Garden Photography

• Catalogues describing these programs are
available at the Gifford House. Call the
number below for registration information.

SUNDAY ECOLOGY PROGRAMS
Free public programs are held on the first and
third Sunday of each month, except over
holiday weekends. Programs begin at 2 p.m. at
the Gifford House on Route 44A unless
otherwise noted. Call (914) 677-5359 to
confirm the day’s topic.

June 21 : Weather and Pollution Monitoring
at lES — How Do We Do It and Why, a walk
led by Vicky Kelly.

July 19: A Stream Walk, led by Dr. Stuart
Findlay

Aug. 2: An Eye on the State of Our Forests,
led by Dr. Gary Lovett
Aug. 16: to be announced

• For outdoor programs, long pants, socks and
sturdy waterproof shoes are strongly sug-
gested. In case of inclement weather, call
(914) 677-5358 after 1 p.m. to learn the status
of the day's program.

GREENHOUSE

The IBS greenhouse is a year-round tropical
plant paradise as well as a site for controlled
environmental research. The greenhouse is
open during Arboretum hours. Admission is by
free permit from the Gifford House.

GIFT SHOP

Senior Citizens Days: On Wednesdays, senior
citizens receive a 1 0 % discount on all
purchases (except sale items).

Inventory Sale: 10% discounts in June on all
merchandise

ARBORETUM HOURS
(Summer hours: May 1 - September 30;
closed on public holidays)

Arboretum grounds are open Mon. - Sat.,

9 a.m. to 6 p.m.; Sun. 1 - 6 p.m.

(The Greenhouse closes at 4 p.m. daily.)

The Gift and Plant Shop is open Tues. - Sat.,

1 1 a.m. to 5 p.m. and Sun. 1-5 p.m.

(Closed weekdays from 1 - 1 :30 p.m.).

• All visitors must obtain a free permit at the
Gifford House for access to the Arboretum.
Permits are available until 5:00 p.m. daily.

MEMBERSHIP

Become a member of the Mary Flagler Cary
Arboretum. Benefits include a member's rate
for IBS courses and excursions, a 10% discount
on purchases from the Gift Shop, a free
subscription to the IBS NBWSLBTTBR, and
parking privileges and free admission to the
Bnid A. Haupt Conservatory at The New York
Botanical Garden in the Bronx. Individual
membership is $30; family membership is $40.
For information on memberships, contact Janice
Claiborne at (914) 677-5343.

For more information, call (914) 677-5359 weekdays from 8:30 - 4:30.

Nonprofit Org.
U.S. Postage
PAID

Millbrook, N.Y.
Permit No. 16

Volume 9, Number 2
March - April 1992

100% Recycled
Paper