June 12, 2006


Zebra mussels stimulate algae growing on the bottom of Lake Erie

Ann Arbor, MI — Algae along the bottom of Lake Erie have higher productivity in the presence of zebra mussels. These rates can far exceed growth rates of algae suspended in the water column.

This study confirms the finding that zebra mussels are re-engineering Lake Erie's biological community. The accidental introduction of zebra mussels into the Great Lakes during the late 1980s has led to many changes, including decreases in algae suspended in the water column and the resulting increase in water clarity that extends the area over which benthic plants can grow. This re-engineering affects many organisms in the Great Lakes.

"Zebra mussels and related quagga mussels are very effective at removing particles from the water," says Bob Hecky, an internationally renowned biologist studying large lakes around the world. "The particles removed from the water column include microscopic plants and animals whose their remains are deposited on the bottom of the lake."

Once removed from the water column, nutrients in these particles can stimulate plants such as Cladophora - a filamentous green alga - that grows attached to rocks. Hecky believes that this represents a fundamental shift in how Lake Erie functions and offers insight into understanding why Cladophora is now so common.

Cladophora can be considered a nuisance because large mats become detached in mid to late summer and wash up on beaches. This study demonstrates that the presence of mussels appears to increase the growth of Cladophora. Zebra mussels may also delay midsummer detachment of Cladophora by reducing or delaying nutrient stress.

Original Publication Information

Results of this study, "Initial Measurements of Benthic Photosynthesis and Respiration in Lake Erie," are reported by John-Mark Davies and Robert E. Hecky in a special issue on the current status of Lake Erie in the Journal of Great Lakes Research, (Volume 31, sup2, pp. 195-207) published by the International Association for Great Lakes Research, 2005.


For more information about the study, contact Robert Hecky, Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1;; 519-888-4567.

For information about the Journal of Great Lakes Research, contact Stephanie Guildford, Scientific Co-Editor, Large Lakes Observatory, University Minnesota Duluth, 2205 East Fifth Street, Duluth, Minnesota, 55812-2401;; (218) 726-8064.


Since 1967, IAGLR has served as the focal point for compiling and disseminating multidisciplinary knowledge on North America's Laurentian Great Lakes and other large lakes of the world and their watersheds. In part, IAGLR communicates this knowledge through publication of the Journal of Great Lakes Research, available to members in print and electronic form. A searchable archive of the journal is available online and includes the abstracts of articles from the journal's inception in 1975 through the most recent issue. In addition, complete articles are available to members who have signed up for an electronic subscription.