NOAA GREAT LAKES SEMINAR SERIES|
Tuesday, October 14, 2003
"Newly Discovered and Corroborated Deleterious Effects of Zebra Mussels on Lake Ecosystems"
Dr. David F. Raikow
GLERL Main Conference Room
2205 Commonwealth Blvd.
Ann Arbor, MI 48105
Although the invasion of zebra mussels (Dreissena polymorpha) is now nearly twenty years old and has been studied extensively, serious deleterious effects continue to be uncovered. A series of experiments and observational studies was conducted throughout the lower peninsula of Michigan to ascertain the effects of zebra mussels on inland lakes, a set of ecosystems invaded relatively recently. These studies included a state-wide survey of phytoplankton communities across a Total Phosphorus (TP) gradient and large scale 50,000-L mesocosm experiments in Gull Lake. Other mesocosm experiments at the pond facility of the Kellogg Biological Station, Michigan State University, demonstrated Dreissena impacts on larval fish growth rates through food web interactions. Surveyed lakes with Dreissena were found to have lower concentrations of Dissolved Organic Carbon (DOC), which could render lakes more susceptible to the ill-effects of UV-B radiation. Lakes with Dreissena were also found to have less total phytoplankton biomass. Surprisingly, there was a positive relationship between Dreissena presence and dominance of the noxious cyanobacterium Microcystis aeruginosa in low nutrient lakes. Mesocosm experimentation on Dreissena and Microcystis displayed effect reversals between years, illustrating complex interactions between consumers, prey, and nutrient levels. Among the conclusions of this work is the possibility that monitoring and abatement of nutrient inputs to lakes may not be sufficient to predict and control cyanobacterial dominance of Dreissena-invaded lakes.
For more information, contact:
Dr. David Reid
-- David F. Reid, Ph.D. U.S. Department of Commerce National Oceanic and Atmospheric Administration Great Lakes Environmental Research Laboratory 2205 Commonwealth Blvd. Ann Arbor, MI 48105-2945 Voice: 734-741-2019 FAX: 743-741-2055 GLERL home page: http://www.glerl.noaa.gov