Do Invasive Mussels Restrict Offshore Phosphorus Transport in Lake Huron?

• Published in: Environmental science & technology Vol. 45; no. 17; pp. 7226 - 7231
• Main Authors: Cha, YoonKyung, Stow, Craig A, Nalepa, Thomas F, Reckhow, Kenneth H
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.09.2011
• Subjects: Animal, plant and microbial ecology; Animals; Applied ecology; Bays - chemistry; Biological and medical sciences; Bivalvia - metabolism; Canada; Characterization of Natural and Affected Environments; Chlorides - analysis; Diporeia; Dreissena polymorpha; Ecosystem; Ecotoxicology, biological effects of pollution; Food Chain; Fresh water environment; Freshwater; Fundamental and applied biological sciences. Psychology; Lakes; Lakes - chemistry; Michigan; Mollusks; Nonnative species; Offshore; Phosphorus; Phosphorus - analysis; Sedimentation & deposition; Water Pollutants - analysis; Lake Huron; Great Lakes of America; North America; America; Canada; Michigan; USA, Michigan L., Saginaw Bay; North America, Great Lakes; North America, Huron L; Freshwater environment; Invasive species; Bivalvia; Nutrient; Phosphorus; Invertebrata; Mollusca; Transport; Dreissena polymorpha; Eutrophication
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es2014715

Dreissenid mussels were first documented in the Laurentian Great Lakes in the late 1980s. Zebra mussels (Dreissena polymorpha) spread quickly into shallow, hard-substrate areas; quagga mussels (Dreissena rostriformis bugensis) spread more slowly and are currently colonizing deep, offshore areas. These mussels occur at high densities, filter large water volumes while feeding on suspended materials, and deposit particulate waste on the lake bottom. This filtering activity has been hypothesized to sequester tributary phosphorus in nearshore regions reducing offshore primary productivity. We used a mass balance model to estimate the phosphorus sedimentation rate in Saginaw Bay, a shallow embayment of Lake Huron, before and after the mussel invasion. Our results indicate that the proportion of tributary phosphorus retained in Saginaw Bay increased from approximately 46–70% when dreissenids appeared, reducing phosphorus export to the main body of Lake Huron. The combined effects of increased phosphorus retention and decreased phosphorus loading have caused an approximate 60% decrease in phosphorus export from Saginaw Bay to Lake Huron. Our results support the hypothesis that the ongoing decline of preyfish and secondary producers including diporeia (Diporeia spp.) in Lake Huron is a bottom-up phenomenon associated with decreased phosphorus availability in the offshore to support primary production.