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Ongoing project: Dynamics of the deep chlorophyll layer

Annie Scofield (Funded by EPA and Great Lakes Fisheries Commission) 

Deep chlorophyll layers (DCLs) are important features during thermal stratification in large oligotrophic lakes. The presence of a DCL has been observed in all five of the North American Great Lakes, but its ecological significance is not well understood. Annie is working with GLNPO researchers to better understand the ecological importance of the DCL across the Great Lakes, with a particular focus on Lake Ontario in 2013. Greater water clarity in Lake Ontario has led to increased formation of the DCL and a vertical re-structuring of the food web. The shift in primary production from the epilimnion to the metalimnion has caused a re-distribution of food resources, which will impact the bioenergetics of zooplankton, mysids and fish. Annie is exploring several technologies (i.e. Triaxus array, Fluoroprobe, and autonomous gliders) to track the formation and dissipation of this feature. She is also studying the zooplankton community in Lake Ontario and Lake Michigan to better understand how DCL formation affects the distribution and feeding patterns of different zooplankton species.