Collaborative Research: BoCP-Implementation: The Impact of Climate Change on Functional Biodiversity Across Spatiotemporal Scales at Lake Tanganyika, Africa

Lake Tanganyika is renowned for its biodiversity, but the spectacular life in this vast and ancient ecosystem is threatened by warming temperatures in ways that are not well- understood. As one of sub-Saharan Africa’s most prolific inland fisheries, a healthy Lake Tanganyika is critically important to the nutrition of four developing nations. If global warming alters internal processes that affect the fish production in Lake Tanganyika, then the food security for millions of people will suffer. Moreover, the impacts of environmental change on the characteristics of different groups making up Lake Tanganyika’s open water and lake floor communities, as well as interactions among these groups, are unknown. This project aims to study the response of Lake Tanganyika’s food web to several different scenarios of climate change using sediments, fossils, and genetic tools. The results of the project will reveal how aquatic organisms, particularly economically valuable fish, respond to changes in temperature and precipitation within large tropical lakes. With this information, fisheries and ecosystem managers will be better equipped to safeguard food resources and biodiversity in their areas of responsibility. Finally, this project will include strong international partnership to train students, conduct workshops and develop materials for public audiences. This project will use Lake Tanganyika’s high-resolution sedimentary record to set up a series of historical experiments to track functional biodiversity lake-wide. This framework integrates geochemical, fossil, and genomic tools to assess open water and bottom- dwelling community structures and functions under different scenarios of climate change, as well as the physical and physiological responses of key organisms to these changes. Because the hydroclimatic conditions of the Holocene are underrepresented in historical data, this approach provides the opportunity to evaluate the consequences of environmental change for Lake Tanganyika’s food web in a way that was previously impossible to know. In addition, the project will identify shared and divergent responses to climatic fluctuations across the lake’s diverse fauna and link these responses to trait- based understanding of community assembly and functioning. This work holds potential for predicting changes in biodiversity amidst severe climatic uncertainty in large tropical lakes.