As an ecosystem, Green Lake in Fayetteville, N.Y. is a unique place. It was one of the first lakes discovered to be meromictic, meaning that it is divided into layers that stay separated all year long, with little to no mixing. The layers are kept distinct by different concentrations of chemicals. The top, or mixolimnion layer is oxygenic, and is separated from the deeper, monimolimnion layer by a chemocline, an area where the chemical makeup of the water changes drastically.
The unique chemical makeup of the lake makes it biologically unique as well, since different microbial communities can survive in the different chemical environments at each layer. This summer, two Hamilton students, Amy Rumack '09 and Valerie Valant '10, are working on a collaborative research project with Assistant Professor of Biology Michael McCormick to study the microbial diversity in the lake. They will collect samples from the surface to a depth of 50 meters, and will use a complex chemical process to identify them genetically. Then they will be able to create a phylogenetic map to show how the organisms are related and how biological diversity differs based on the lake's chemistry.
The top, mixolimnion layer of the lake supports aerobic microbes due to its higher oxygen levels, while monimolimnion layer is home to bacteria that oxidize sulfur to survive, since the water at that depth is anoxic, lacking in oxygen. The chemocline in the middle is home to a group of organisms that are much more diverse than those found in the mixolimnion layer.
To investigate the specific makeup of the microbial communities, however, Rumack and Valant will take water samples at varying depths and analyze the organisms genetically. They will study a certain portion of the ribosomal DNA in a process called denaturing gradient gel electrophoresis, or DGGE. In this process, the DNA samples migrate down a gel that contains a progressively higher concentration of denaturants, causing the samples to lose their shape, or denature, as they travel. When they have denatured to the point that the strands separate, the DNA sections stop migrating down the gel. Since different organisms have chemically different DNA, the samples will denature at different rates, resulting in "bands" along the gel that represent variations in the microbial community from where the sample was taken. Using this knowledge, Rumack and Valant can start to sequence and identify the DNA.
This project, Rumack says, is unique because it draws from so many different scientific disciplines, including biology, biochemistry, microbial ecology, and geology. Having worked with Professor McCormick last year on a different project, she is using the research this summer as the basis for her senior thesis. Valant, who is experiencing summer research for the first time, notes that she was surprised at how slow the progress has been at the beginning of the project. "It teaches you patience," she says. The students say that they enjoy the independence of summer research, as well as the chance to collaborate with a professor on an individual level.
Both students are biology majors, and Rumack is an anthropology minor, while Valant is minoring in women's studies. In her spare time, Valant works in the Alumni Office and guides tours for the Admissions office, as well as coaching youth soccer in the Cornhill area of Utica. Rumack is a member of the equestrian team and works at Café Opus during the school year. After Hamilton, both students are considering medical school.
-- by Laura Bramley
The unique chemical makeup of the lake makes it biologically unique as well, since different microbial communities can survive in the different chemical environments at each layer. This summer, two Hamilton students, Amy Rumack '09 and Valerie Valant '10, are working on a collaborative research project with Assistant Professor of Biology Michael McCormick to study the microbial diversity in the lake. They will collect samples from the surface to a depth of 50 meters, and will use a complex chemical process to identify them genetically. Then they will be able to create a phylogenetic map to show how the organisms are related and how biological diversity differs based on the lake's chemistry.
The top, mixolimnion layer of the lake supports aerobic microbes due to its higher oxygen levels, while monimolimnion layer is home to bacteria that oxidize sulfur to survive, since the water at that depth is anoxic, lacking in oxygen. The chemocline in the middle is home to a group of organisms that are much more diverse than those found in the mixolimnion layer.
To investigate the specific makeup of the microbial communities, however, Rumack and Valant will take water samples at varying depths and analyze the organisms genetically. They will study a certain portion of the ribosomal DNA in a process called denaturing gradient gel electrophoresis, or DGGE. In this process, the DNA samples migrate down a gel that contains a progressively higher concentration of denaturants, causing the samples to lose their shape, or denature, as they travel. When they have denatured to the point that the strands separate, the DNA sections stop migrating down the gel. Since different organisms have chemically different DNA, the samples will denature at different rates, resulting in "bands" along the gel that represent variations in the microbial community from where the sample was taken. Using this knowledge, Rumack and Valant can start to sequence and identify the DNA.
This project, Rumack says, is unique because it draws from so many different scientific disciplines, including biology, biochemistry, microbial ecology, and geology. Having worked with Professor McCormick last year on a different project, she is using the research this summer as the basis for her senior thesis. Valant, who is experiencing summer research for the first time, notes that she was surprised at how slow the progress has been at the beginning of the project. "It teaches you patience," she says. The students say that they enjoy the independence of summer research, as well as the chance to collaborate with a professor on an individual level.
Both students are biology majors, and Rumack is an anthropology minor, while Valant is minoring in women's studies. In her spare time, Valant works in the Alumni Office and guides tours for the Admissions office, as well as coaching youth soccer in the Cornhill area of Utica. Rumack is a member of the equestrian team and works at Café Opus during the school year. After Hamilton, both students are considering medical school.
-- by Laura Bramley
