| by Gerry Boyle ’78

Lake study by Colby faculty and student researchers doesn’t stop for the Maine winter.

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Miselis Professor of Chemistry Whitney King, left, with students taking water samples from Great Pond in Belgrade as part of an ongoing study of water quality in the lake.

Colby science students, working with Denise Bruesewitz, assistant professor of environmental studies, recently cut through 32 inches of ice on Great Pond in the Belgrade Lakes at the location where a Colby research buoy is moored when the ice is out. The students, who traveled to the location by snowmobile, were joined by Peter Countway, senior research scientist at Colby partner Bigelow Laboratory for Ocean Sciences, who was conducting his first freshwater sampling.

Bruesewitz and her students are conducting a seasonal study of the Belgrade Lakes and streams in its watershed to understand how shifts in nutrient limitation affect phytoplankton growth. The study involves monitoring and analysis of chlorophyll levels, which grow with the addition of nutrients like phosphorous. Bruesewitz’s students are collecting samples (including through the ice), conducting experiments by adding different nutries to the water, filtering for chlorophyll, and measuring the content with a fluorometer, she said. “We will grab another set [of samples] … once the ice comes off and it’s safe to get a boat in the water,” Bruesewitz wrote in an e-mail.

The results thus far have demonstrated the importance of limiting both phosphorus and nitrates in order to improve and preserve water quality, she said.

Countway is working on a pilot study of the genetic diversity of the microbial community in Great Pond. Bigelow, he said, has new cutting-edge DNA sequencing technology that will be used to survey the diversity of bacteria and other microbes in the lake. Countway’s work will be coordinated with the ongoing experiments, conducted by Bruesewitz and her students, on nutrient limitation and the effect of nutrients on biological productivity of the lake. “It’s a great fit,” he wrote in an e-mail.

In the meantime students working with Miselis Professor of Chemistry Whitney King continue to study water quality using data supplied by the remote monitoring buoy. This winter, King’s students were in the lab writing computer code that will allow for display of information from the buoy, which communicates with Colby labs using a dedicated mobile phone. The monitoring buoy and its various sensors will be returned to the lake as soon as the ice melts, King said.