On an overcast morning in July, Haley Batchelder '19 gathered materials for her research on Sebago Lake: a notebook, pen, bendable ruler, life jacket, and coring device. She boarded the Portland Water District’s (PWD) pontoon boat with her team: boat driver and PWD Water Resource Specialist Nate
Whalen, SJC students Joseph O'Reilly '18 and Adrienne Dolley '20, and SJC Science Professor Dr. Johan Erikson.
The crew set off from the Lower Bay of Sebago Lake, which is a restricted area, managed by the Portland Water District. In 1913 the Maine Legislature recognized Sebago Lake as the drinking water supply for Greater Portland and passed a law to prohibit bodily contact within two miles of the
District’s intakes. Because Sebago Lake provides 15% of Maine’s drinking water, it is one of the state’s most important natural resources.
The excellent water quality of Sebago Lake means it is exempt from the expensive filtration process required of most surface water sources. However, a threat to that quality can be the rapid increase in the population of algae in an aquatic system, known as algal blooms, which can be caused by
the release of phosphorus. As algae plants grow and die, the bacteria increase and use up dissolved oxygen, creating conditions in which fish and aquatic insects are unable to survive. Furthermore, these conditions can release more phosphorous from the sediments on the bottom of the lake, depending on the geochemistry
of those sediments creating a feedback cycle: algae bloom results in phosphorous release, which can then lead to more algae. Haley therefore chose to study the phosphorus release in the lake in relation to concentrations of aluminum, iron, and calcium in sediments to evaluate a condition that could
potentially put the lake at risk.
She boated up to a two-mile stretch called Jordan Bay with her crew to collect three core samples of sediment for analysis, using a cylindrical tube that plunged deep below the water’s surface, and divided them up into two centimeter increments. She then brought the samples back to the
chemistry lab at Saint Joseph’s College. Haley performed the Psenner sequential extraction method for each sediment sample and discovered that the molar ratios of aluminum to phosphorus and iron to phosphorus fell below the thresholds (25:1 and 3:1, respectively), indicating that the lake’s conditions promote a
high release of phosphorus.
What does this mean for Sebago? High levels of phosphorus can be caused by increased development around the watershed when sediment runoff collects in the lake from fertilized lawns and parking lots. As more people move to the greater Sebago region and as more tourists visit the lake, their
development increases the amount of phosphorus entering the lake. Additionally, due to climate change, winter ice is forming later and melting earlier in the year, which extends the growing season for algae. Combined with heavier rainfall and more extreme storms, the resulting algal blooms could force water
filtration. Not only would this affect the health of the ecosystem and drinking water, but it could also have a major economic impact on the scenic lakes region. The geochemistry of the sediments seems to indicate that additional phosphorous release during anoxia is possible, so preventing algae blooms by
minimizing excessive algal growth (eutrophication) is all the more important.
Haley presented her findings to members from the
Lakes Environmental Association (Colin Holme, Ben Peierls, and Peter Lowell), the
Portland Water District (Nathan Whalen, Brie Holme, Paul Thomas Hunt, and Chad Thompson), and University of Maine professors Aria Amirbahman and Stephen Norton. Following her presentation, the group discussed further research questions and opportunities with each member bringing his or expertise to the table. Haley wonders, for instance, if the sediment conditions in Jordan Bay are similar to those in the Big Basin. She also wonders about the role of
depth: Sebago is Maine’s deepest lake at over three hundred feet. This may be a crucial buffer against a possible phosphorous feedback cycle. In Haley’s final written report, she explains that with “a larger water to sediment ratio, the phosphorus released by the sediment conditions may not be significant enough
due to the large amount of water” and if the phosphorus is released deep enough it might not be “biologically available due to lack of oxygen and light.”
PWD Water Resource Specialist Nate Whalen is grateful for research like Haley’s and he explained that in order to have a filtration waiver system for the lake, “you need to have people to protect the water. It’s important for us to collaborate with the community because we’re only a few
people. It takes a whole community to protect the water supply—whether it’s the College, the Maine Warden Service, the Department of Environmental Protection, the Environmental Protection Agency, or public citizens.” He also pointed out that, “It’s a lot easier to keep the lake clean to start with, rather than to
try to treat it after.”
Haley enjoyed sharing her project with stakeholders from throughout the state. “It’s important for Sebago Lake to stay healthy. Any data we can get is useful for the community,” she said. Saint Joseph’s College Professor of Science Dr. Emily Lesher served as an advisor for this project and
Haley obtained financial support for her research through the Maine Space Grant Consortium, an affiliate that funds research of interest to NASA through the congressionally established National Space Grant College and Fellowship Program.
Saint Joseph’s College offers several research and scholarship opportunities for students interested in pursuing science at a college that has convenient access to the ocean, mountains, lakes, and rivers. Most recently, the National Science Foundation (NSF) has awarded Saint Joseph’s College a
five-year $647,000 grant to encourage academically-talented students, who have demonstrated need of financial assistance, to enter into and succeed in a community of young scientists. The first group of Saint Joseph’s College Science Scholars will be selected from first-year students entering in the fall
of 2018 who are committed to pursuing a range of fields, including: chemistry, biology, environmental science, biochemistry, and marine science. Learn more at
-By Emma Deans, SJC Communications Officer