The Gloeo Project

Gloeotrichia echinulata is a nitrogen-fixing, colonial cyanobacterium that has recently begun to cause noticeable blooms in recreationally-important oligotrophic lakes across northern New England (including Lake Sunapee, which is ~30 miles south of Dartmouth). This is quite unusual, as we generally expect nuisance cyanobacterial blooms in high nutrient (eutrophic) systems, not low nutrient systems.

Together with Kathie Weathers (Cary Institute of Ecosystem Studies), Holly Ewing (Bates College), Dartmouth alumna Cayelan Carey 06 (now a graduate student at Cornell University), and current grad students Sam Fey and Jess Trout-Haney, I am working on several related projects to understand the causes of these blooms and their potential consequences for lake ecosystems.

Our research questions include:

       What are the consequences of G. echinulata blooms for lake phosphorus cycling? Does G. echinulata recruitment from the sediments increase water column P? If so, can other organisms take advantage of this newly available P?

       What role does nitrogen fixation by G. echinulata play in lake nitrogen cycling?

       Why is G. echinulata invasive in oligotrophic lakes? Preliminary results suggest that it has been present in low numbers in the past, but is only now recently in noticeable numbers. Does recent climate change or watershed development play a role?

       Within a season, what triggers G. echinulata blooms?

       What are the potential consequences of G. echinulata blooms for humans, such as human health consequences and disruption of ecosystem services?

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Author: Kathy Cottingham (kathryn.cottingham AT
Last Updated: 02 April 2012