by Michigan Technological University, Jan 21, 2021 in ScienceDaily

NASA-funded research on the 11 largest freshwater lakes in the world coupled field and satellite observations to provide a new understanding of how large bodies of water fix carbon, as well as how a changing climate and lakes interact.

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One of the most remarkable aspects of the results is just how fast changes in these freshwater lakes have occurred — a noticeable amount in fewer than 20 years. The research contributes to NASA’s Carbon Monitoring System’s goal of determining how much freshwater lakes contribute to the global carbon cycle.

“Three of the largest lakes in the world are showing major changes related to climate change, with a 20-25% change in overall biological productivity in just the past 16 years,” Fahnenstiel said.

More Than Algae

In the 16 years of data, Great Bear and Great Slave lakes in northern Canada saw the greatest increases in productivity, while Lake Tanganyika in southeastern Africa has seen decreases. The trends are linked to increases in water temperatures, as well as solar radiation and a reduction in wind speed.

Sayers said looking at productivity, algal abundance, water clarity, water temperature, solar radiation and wind speeds at freshwater lakes provides a richer picture of the overall ecosystem.

“Temperature and solar radiation are factors of climate change,” Sayers said. “Chlorophyll and water transparency changes are not necessarily caused by climate change, but could be caused by eutrophication or invasive species, like quagga mussels.”

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