Deborah Dila ACF Abstract FY11

"Microbes and Carbon Flux in a Great Lakes Watershed"

Conference Name: 54th International Conference on Great Lakes Research

DILA, D.K.1 and BIDDANDA, B.A.1, 1GVSU Annis Water Resources
Institute, Muskegon, MI; 2GVSU Annis Water Resources Institute, Muskegon,
MI. Microbes and Carbon Flux in a Great Lakes Watershed.

Microorganisms make up the majority of Earth's biological diversity and
biomass. They are responsible for cycling roughly half of carbon and oxygen
between the atmosphere, hydrosphere and lithosphere. In marine and
freshwater environments microbial plankton are the leading primary
producers as well as consumers of organic carbon. Although many details of
the relationship of microbes to carbon flux remain a mystery, we do know
that freshwater ecosystems are highly reactive sites of carbon metabolism and
land-margin coastal ecosystems are emerging as key hotspots in the global
carbon cycle. Our work examined seasonal changes in carbon flux and
microbial community composition along a land to lake gradient in a major
West Michigan watershed. From carbon-rich riverine waters to nutrient poor
pelagic lake waters, sampling sites included Cedar Creek, Muskegon River,
Muskegon Lake and offshore Lake Michigan. Maxima in net primary
production occurred in Muskegon Lake (~30-fold higher than Muskegon
River and 240-fold higher than Lake Michigan) coincident with maxima in
Chlorophyll a concentration and minima in nitrate concentration at this
drowned river mouth site. Our findings suggest Muskegon Lake is a highly
productive estuary-like transition zone in this Great Lakes watershed.

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