Biogeochemical controls on sediment nutrient cycling and the dynamics affecting cyanobacterial ecology
Investigators: Greg Druschel, Donna Rizzo, Mary Watzin

Lake Champlain, as most water bodies on the planet, suffers from periodic episodes of algal blooms, some of which are primarily populated by species of cyanobacteria that produce dangerous neurotoxins. There is increasing evidence that the N:P ratio in Lake Champlain waters is a primary factor in determining the ecological makeup of cyanobacterial populations, and several areas of the lake have seen significant toxic algal blooms. The cycling of nutrients between sediments in several bays and the overlying water column has been shown to be largely due to changes in redox geochemistry which affect the minerals present in these bay sediments. We have further shown that phosphorus and nitrogen are affected by the overall chemical changes in these sediments differently. We are investigating, through a series of joint projects and the development of a modeling framework, the interdependent associations between the physical, chemical, microbial, and eukaryotic processes which effect cyanobacterial ecology.

Several grants from the Vermont Department of Environmental Conservation, U.S. Environmental Protection Agency, and other sources have, continue, and are in review supporting these efforts. We bring together our expertise, equipment, and methods to work together in a multidisciplinary group - giving students, collaborators, and ourselves an opportunity to see and work with a complete system and learn from each other in hopes of discovering new links describing ecological changes in this environment.