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.