Yvonne Vadeboncoeur, Ph.D., associate professor in the Department of Biological Sciences, is an investigator in the collaborative Tuungane Project Baseline Ecological Study to assess the near-shore biodiversity of Lake Tanganyika. This ecological survey focused on the freshwater component of the Lake Tanganyika Ecosystem. Lake Tanganyika is the second largest and the second deepest freshwater lake in the world. Two key threats to the near-shore biodiversity is sedimentation and over-fishing. The lake is a global hotspot of freshwater biodiversity and a significant source of protein for the millions of inhabitants around the lake. Local farmers’ and fishers’ livelihoods depend on preservation of the region’s rich natural resources.
Open waters of the lake support relatively few species of fish and zooplankton, yet the near-shore waters of Lake Tanganyika support over 280 species of fish, and more than 400 species of invertebrates. The majority of these species are found nowhere else on earth, and over 85% of species live in the narrow band of shallow water at the edge of the lake called the littoral zone. Vadeboncoeur’s group studies the interactions between attached algae and herbivorous fish in Lake Tanganyika. They are trying to figure out how this seemingly nutrient poor lake supports all these fish and this high algal growth.
They are using field and lab experiments to test whether grazing fish increase nutrient turnover and nutrient retention in the littoral zone, and consequently whether fish increase the overall productivity of the littoral zone. In the cyclical nature ecology, the algae growth depends on the fish leaking out nutrients while the algae, using photosynthesis, create carbon compounds that the fish use to meet their energy needs. This tight linkage may explain why high productivity and diversity persists in the face of apparent extreme nutrient scarcity.
The Tuungane Project is a collaboration between The Nature Conservancy, Frankfurt Zoological Society, and Pathfinder International, seeking to address the most significant health and environmental issues within the Greater Mahale Ecosystem in Western Tanzania. Project documentation has been provided by Yvonne Vadeboncoeur from Wright State University, Peter B. McIntyre from University of Wisconsin, Colin Apse and Tim Tear from The Nature Conservancy, African Region, and Ishmael Kimirei from the Tanzanian Fisheries Research Institute.