Newswise — Associate professor of Biology, Michael Twiss, and colleagues from The University of Tennessee, Bowling Green State University, and Environment Canada sailed the entire length of Lake Erie over three days in late February onboard the Canadian Coast Guard Ship Griffon. The purpose of the voyage was to examine the status of microbial ecology of the lake during the depth of winter. Twiss and colleagues are members of the MELEE (Microbial Ecology of Lake Erie Ecosystems) research network, a group US and Canadian researchers formed in 1999 and devoted to exploring the limnology (freshwater oceanography) of this important lake.
Lake Erie is commonly ice covered in winter. In late February 2007, Lake Erie had over 90% of its surface frozen with depths ranging from fractions of an inch in newly opened areas to over 10 feet thick in windrows where wind in open leads blows ice into piles on the ice shelf edge. However, as recently as 2002 there was no ice cover on the lake. Moreover, a four-year running average of percentage ice-cover on Lake Erie calculated by the United States Environmental Protection Agency shows a downward trend, possibly a harbinger of regional climate warming. What impact this could have on how the lake functions is not clear. Some suggest that ice protection prevents sediment suspension and keeps phosphorus, a key algal nutrient locked in sediments. Lower phosphorus levels will reduce the bloom of algae that happens every spring. Algal blooms are considered the prime culprit for the absence of oxygen deep in Lake Erie during the summer months due to the sinking of the algae and their decomposition that consumes oxygen.
One important observation on the February 2007 expedition was the presence of high concentrations of filamentous green algae called Zygnema. These blooms were occurring just below the ice surface forming visible brownish green coloration to the ice. "We know that clear ice with little snow cover will allow ample light through to support planktonic algae " at a time of year when algae capable of surviving cold water will proliferate due to an abundance of nutrients owing to little competition from other algae" , states Twiss. "But we were astonished to see such high levels of filamentous green algae in the vast central region of the lake. These are related to but not the Cladophora green algae that form unsightly mats in the near shore areas of Lakes Erie and Ontario in summer months. We are calling these hotspots of biologic activity CACHEs " Concentrated Algal Communities and Heterotrophic Ecosystems " owing to their hidden nature below the ice surface and the abundance of microbes associated with them. How these CACHE develop and their ecological significance in the Great Lakes is a new and exciting research question for our research group. We have to figure this problem out."
Twiss is the director of the Great Rivers Center (http://www.clarkson.edu/cce/great_rivers.html) at Clarkson University. The St. Lawrence River is the conduit through which the Great Lakes flow to the ocean. The explicit mission of the Great Rivers Center is to ensure that the quality of this freshwater resource is the highest possible. Water quality is defined by chemical purity, ecosystem health, and water ethics. To meet this task the GRC is a focal point for creative multidisciplinary research, scholarly activity and community outreach.
Clarkson University, located in Potsdam, New York, is a private, nationally ranked university with a reputation for developing innovative leaders in engineering, business, the sciences, health sciences and the humanities. At Clarkson, 3,000 high-ability students excel in an environment where learning is not only positive, friendly and supportive but spans the boundaries of traditional disciplines and knowledge. Faculty achieves international recognition for their research and scholarship and connects students to their leadership potential in the marketplace through dynamic, real-world problem solving.
PHOTO CAPTIONS: Twiss.jpg: Clarkson professor Michael R. Twiss is contributing to research that will protect the Great Lakes.Lake-erie.jpg: Ice covering the lake 25 miles offshore in Lake Erie. In late February 2007, over 90% of Lake Erie was covered ice.
[Photograph for media use is available at http://www.clarkson.edu/news/photos/twiss.jpg and http://www.clarkson.edu/news/photos/lake-erie.jpg]
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