|
|
 |
|
|
| Posted 06.04.07 |
Class Uses Local Lake as Laboratory
|
About 30 years ago, unnatural and excessive
biological growth started occurring in the small, man-made Beseck Lake
six miles southeast of Wesleyan's campus.
Septic systems from lakeside homes deposited nutrients into the water,
altering the biogeological cycles of carbon, sulfur, nitrogen and phosphorus
in the aquatic ecosystem.
By 2002, the problem was remedied by connecting the homes to a city sewer
system and the quality of the lake water improved. However, excess algae
growth continued to form, proving that some unwanted nutrients continued to
exist.
“What was still polluting the lake?’” asked Tim Ku,
assistant professor of earth and environmental science. Ku and 18 Wesleyan
students volunteered to help find the answers.
As part of Wesleyan’s Service Learning Course, Environmental Geochemistry
Laboratory, the students had an opportunity to research the lake focusing on
cultural eutrophication – or the result of nutrient pollution in an
ecosystem.
 Prior
to conducting the actual research, Ku taught the class a variety of
geochemical analytical techniques. Classes were held on campus but the
116-acre Beseck Lake served as the laboratory.
The students broke into small groups to conduct individual studies. During
the winter they cut holes frozen-over lake (pictured) and lowered probes
into the water and sediment. The sediment measurements allowed the young
researches to identify changes that have occurred in the lake since 1849,
when the lake was created. Students also analyzed the lake’s water and the
surrounding air.
Sarah Gillig ‘09, an earth and environmental studies major, worked on an
organic sediment deposit study. Her goal was to find what was still causing
the pollution in the lake, which can harm people and kill fish and natural
aquatic life.
“We wanted to know if the problems were caused by outside factors, such as
external organic pollution, runoff from a nearby mountain, or if they were
internal,” Gillig explains. “We ultimately discovered they were internal.”
 Jordan
Schmidt ’08, earth and environmental sciences major, analyzed the amount of
phosphate in the lake’s sediment. High phosphate levels can result in excess
algae growth.
Emily Keeler ‘07, an earth and environmental sciences major, says she took
the Service Learning Class because she’s interested in the ways that humans
impact environments. Keeler focused her Beseck Lake studies on water
chemistry.
By measuring the levels of dissolved oxygen, Keeler was able to investigate
the magnitude of oxygen depletion and also whether the lake is overturning
and mixing. She and her peers calculated alkalinity and measured ion
concentrations in the water to determine existing contaminations.
“It’s difficult to look at this ecosystem and see how it’s being destroyed,”
Keeler says. “People want to use it for recreation. They aren't necessarily
thinking about the fact that in order for the lake to not be eutrophic
depends on a balanced lake ecosystem. That means they’re going to have to
change parts of their lifestyle, like not using chemical fertilizers that
run into the lake.”
Ku says once excess phosphate enters the lake, much of it is continuously
cycled from the sediments into the water column. The Town of Middlefield has
submitted a $100,000 bond proposal to the Connecticut State Bond Commission
to improve the water quality and clarity of Beseck Lake. The bond has been
approved by the Environment Committee and the Finance Committee, and is
awaiting a vote.
 To
solve the algae problem, the class investigated the use of alum, a compound
that binds phosphate. While this treatment could decrease the algae blooms
at Beseck Lake the students cautioned that an alum application must be
carefully designed and monitored. Too much alum may harm aquatic life such
as fish; too little will not inhibit the algae growth.
“There is no easy solution for eutrophication at Beseck Lake, the nutrients
can be very difficult to remove or inactivate,” Ku says. “Hopefully, the
class research will lead to the remediation of the lake.”
The Service Learning project was held in cooperation with the Beseck Lake
Association. Students took turns presented their finding to 35 members of
the lake community on May 8.
“For a long time we have wondered whether the nutrients in the lake were
caused by leaves washing down the mountain, farm animals that live on either
end of the lake, or sewage that is stored in the sediment after 75 years of
septic tank leakage,” says Richard Boynton, president of the Beseck Lake
Association. “The students answered this question. Middlefield is lucky that
Wesleyan provided this valuable research study, which would have otherwise
cost us thousands of dollars.”
Gillig says the Service Learning program is a valuable addition at Wesleyan,
and provides them with practical experience in things that are otherwise
very abstract.
“Once you've done it yourself, you have a completely different comprehension
and appreciation for things,” she says.
|
|
By Olivia Bartlett, The Wesleyan Connection
editor. Photos contributed by Tim Ku and his class. |
|
|
 |
|
|
