Indiana State University Newsroom

A new study co-authored by two Indiana State University professors is sounding the alarm on the impact climate change could have on one of the world's most vulnerable regions.

Faculty members Jeffery Stone and Jennifer Latimer of the Department of Earth and Environmental Systems joined others, including Michael McGlue of the University of Kentucky, who led the study.

They conducted research at Lake Tanganyika - a major African fishery. The results, which published Oct. 9 in Science Advances, show how certain changes in climate may place the fishery at risk, potentially diminishing food resources for millions of people in this area of eastern Africa.

"Lake Tanganyika's fish are a critically important resource for impoverished people from four nations (Tanzania, Democratic Republic of the Congo, Burundi and Zambia) and resilience to environmental change in that region is quite low," McGlue said. "Our study revealed that high frequency variability in climate can lead to major disruptions in how the lake's food web functions."

Small pelagic fish, known locally as dagaa, are abundant in Lake Tanganyika, and their conservation is pivotal to the food security and economy of rapidly growing and largely impoverished segments of these four nations.

Dagaa feed on algae and plankton, which means greater algae production in the lake results in more fish. How this aquatic food web responds to external forces, like climate, is critical for identifying vulnerabilities and maintaining healthy fish stocks. But until now, very limited information existed on how Lake Tanganyika may respond to such forces.

"Our record is unique - it has a high temporal resolution and its location in the southern basin of Lake Tanganyika," Stone said. "Because each sample represents a short interval in time, it provides the necessary detail to capture abrupt change associated with inter-annual teleconnective processes, such as El Niño."

"Diatoms, which are my specialty, are a type of microscopic golden-brown algae with a siliceous skeleton that fossilizes in lake sediments. Diatom productivity is closely associated with upwelling in the lake and in this record, they provided pivotal information for reconstructing past upwelling events over the last several thousand years. As a result, we were able to observe a clear link between enhanced upwelling in the southern basin and inter-annual variability."

Said Latimer: "Lake Tanganyika is such an important water and food resource in eastern Africa. It is important that we understand how the lake responded to climate change in the past so that we can better predict the impacts of future climate change in the region."

"Understanding the connections between climate and fish stocks can lead to informed policy decisions that have the potential to ensure these resources are sustainable for future generations."

The study, titled "Solar irradiance and ENSO affects food security in Lake Tanganyika, a major African inland fishery," can be read in full in Science Advances at https://advances.sciencemag.org/.

This research was supported by the UK-Pioneer Endowment, the Society of Exploration Geophysicists/Geoscientists Without Borders and the National Science Foundation.