Mark Gessner is a freshwater ecologist with a long-standing interest in understanding consequences of global environmental change on ecosystem processes and biodiversity in streams, wetlands and lakes. He is a guest scientist at the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), a faculty member of the University of Duisburg-Essen, both in Germany, and an adjunct professor at the Australian Rivers Institute (ARI) of Griffith University in Australia. Currently he serves as president of SFS.