09 Feb 2021

The ecology of the North American Great Lakes has been dramatically altered by the invasive zebra and quagga mussels. A key question is whether this biological change has altered whole-ecosystem biogeochemistry, in particular the cycling of phosphorus, a key nutrient that limits the biological productivity. Prof. Jiying Li, Assistant Professor of Ocean Science at HKUST and her collaborators constructed a mass balance model to evaluate the impact of the invasive mussels on the phosphorus cycle. The results suggest that a single species, the invasive quagga mussel, is now the primary regulator of phosphorus cycling in the lower four Great Lakes, owing to their enormous biomass. The research team found that the increase of mussel biomass and the consequent enhancement of benthic phosphorus fluxes have pushed the Great Lakes to a new dynamic regime where the geochemistry is controlled by mussel physiology and population dynamics, and its responses to external nutrient load have become muted. The results forewarn similar ecological changes in lakes across Europe and North America which have been invaded by the quagga and zebra mussels.

The research was recently published in the Proceedings of the National Academy of Sciences of the United States of America on February 9, 2021: https://www.pnas.org/content/118/6/e2008223118

Figure 1. Quagga mussels colonize the bottom of Lake Michigan (80 m depth) at a density of nearly 10,000 per m2 (image courtesy of John Zalusky)

Figure 2. Invasive quagga mussels extend their syphons from the sediment of Lake Michigan to feed and breath (image courtesy of Sergei Katsev)