Dr.Soren Brothers, School of Environmental Sciences "Changing Winds: How Carbon Cycles Respond to a Shifting World"

In recent decades researchers have come to realize that lakes can act both as important sinks and sources of carbon with respect to the atmosphere. Furthermore, we now know that the amount of carbon buried in a lake’s sediments or emitted to the atmosphere (as carbon dioxide and methane) can change over time. However, our understanding of the environmental and ecological mechanisms controlling these changes is lacking. My work has focused specifically on the direct and indirect effects of humans on carbon cycling in aquatic ecosystems. I will here present the results of my recent research which focused on the effects of ecological regime shifts (between clear-water and turbid states) and brownification (increases in dissolved organic carbon concentrations) on productivity and the fate of carbon in shallow lakes. I will furthermore present my current work within the CREATE Great Lakes program at the University of Guelph, in which I am examining the changing role of benthic primary production in the Laurentian Great Lakes since the 1970s, following widespread oligotrophication and the effects of invasive mussels.