Tuesday, August 20, 2019

Inland waters’ effect on climate change

Cara Munn ’15

Staff Writer

Last Friday, on April 12, 2013, Thomas McKenna Meredith ’48 Postdoctoral Fellow in Environmental Science Sarah Cullison Gray delivered a special lecture on the impact of climate change on freshwater land resources in McCook Auditorium. Though she originally majored in chemistry at St. Mary’s College of Maryland, when she graduated from there she went on to study oceanography at the most unlikely of places: the University of Montana. Her specialties now include environmental chemistry and problems in acquatic biogeochemistry. Her research is primarily in the global carbon cycle, Sensor Design, and Marine and Freshwater Biochemistry. She has three publications out and since 2009 has given eight lectures in Environmental Science.

The lecture that she gave this past Friday, entitled “Carbon Cycling in Local Connecticut Freshwaters: Assessing Susceptibility to Climate Change,” centered on her work that she did with students this past summer at Batterson Park Pond, Mill Pond, and Wethersfield Cove to study small areas that were largely impacted by climate change. She stressed that she did not take her students to the ocean because the ocean can withstand most of these climate changes. Inland waters may cover a small fraction of the earth, but they are thought to be more and more important in the global carbon budget. Gray had her students, Kate Furgueson ’15, and Erika Adams ‘13 collect 320 water samples approximately 320 times over a 13-week period, which they then measured and studied to draw conclusions about water quality and watershed dynamics.

Gray also pointed out that all the sites that they studied were only ten miles apart yet they all had extremely different dynamics. She showed the audience bird’s eye views of the different ponds, some of which were connected to the Connecticut River. It was striking to see all the sediment that had settled in the Connecticut River, and the loss of water volume of the river over the years, illustrating effects of climate change.

Batterson Park Pond had the clearest water, and Wethersfield Cove had the murkiest. The students could tell because their waders would actually stick to the bottom of the pond surface at Wethersfield Cove. Their surface data, which Professor Gray concentrated on primarily in the latter part of her lecture, involved finding the pH and the factors that made it fluctuate up or down. She spoke about how temperature and pH had virtually no correlation at Mill Pond, and low oxygen. Other things that could have affected the pH at this site include photosynthesis and respiration.

The final part of her lecture focused on how to determine how susceptible an area was to climate change, which is called buffering capacity. She said that sea water systems were much more buffered because they were obviously connected to the ocean. The last thing she mentioned was the presence of carbon dioxide and other gases that are unhealthy for living animals.

Professor Gray will end her tenure at Trinity at the end of this year. She will be replaced by another post-doctorate fellow, and will continue to pursue her studies at another college where she will become an associate professor of chemistry.

In 2011, Trinity received a bequest of $1.2 million in the name of Thomas McKenna Meredith, a 1948 Trinity graduate who died in 2007, establishing a permanent endowment to hire fulltime environmental science fellows. Meredith was an investment banker who had a lifelong passion for Arctic travel and a commitment to environmental research.




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