Nuisance Algae (Cladophora) on Lake Michigan Shores
February 18, 2005. 9:00 AM-3:00 PM.
Lakeshore Technical College,
Lake Michigan Conference Room
Cleveland, WI.

For the past five years, large quantities of decaying algae have been fouling Wisconsin's Lake Michigan Shorelines. The Wisconsin DNR, in collaboration with the Univeristy of Wisconsin Sea Grant Institute, hosted a forum including presentations and discussion on the extent of nuisance algae problems, recent research findings, clean up and mitigation techniques, and next steps. The meeting was oriented towards beach managers, county/city conservation and public health officials, lakeshore residents and concerned citizens.

The forum was sponsored by WDNR, UW Sea Grant, UW Extension, Wisconsin Coastal Management and NOAA. 

Agenda and Presentations (exit Sea Grant website)

Forum Summary

     Despite much research, it's not clear why massive mats of algae have been fouling Lake Michigan beaches in recent years.  Suspect include increasing phosphorous, zebra mussels, lower lake levels, and other factors.  Whatever the cause, getting rid of the ugly, foul-smelling stuff isn't easy.
     Those were the take-home messages from a public forum on the issue held Feb. 18 in Cleveland, Wis.  The day-long event was sponsored by Wisconsin Sea Grant, the Department of Natual Resources and UW-Extension.  About 100 people, including scientists, homeowners, beach managers and concerned citizens filled an auditorium at Lakeshore Technical College.
     Beach managers along Wisconsin's Lake Michigan shoreline said the algae is keeping visitors away.  Several homeowners and members of citizens groups expressed considerable frustration about the unsightliness and odor of the algae, known as Cladophora.  Scientists discussed what is known - and the considerable amount not known - about the problem.
     Erika Jensen, an environmental scientist at the UW-Milwaukee Great Lakes WATER Institute, presented research showing that Cladophora often contains high levels of E. coli and other pathogens, and that it prolongs their survival.
     Many scientists addressed the role phosphorous may play in promoting algae growth.  The DNR's Paul Garrison presented results from a water quality survey that found that phosphorous concentrations in nearshore waters have not increased in recent years.  Thus, the recent blooms of algae are not related to new phosphorous recently entering the lake, Garrison concluded.
     Erica Young, a biologist at the UW-Milwaukee Great Lakes WATER Institute, was one of several scientists who presented research indicating that phosphorous already in the lake's water and sediments, rather than new inputs, may be spurring Cladophora growth.  Vicky Harris, UW Sea Grant water quality specialist, pointed out that roughly two-thirds of all phosphorous in the lake is habored in the sediments and is recylced each year.  Even so, phosphorous input into the lake is the only factor that people can significantly control, Harris said.
     Several scientists noted that zebra mussels have dramatically altered nutrient cycling in the lake by removing phosphorous from the water and concentrating it on the lake bottom, where they live.  The mussels also increase water clarity, allowing more light to reach Cladophora, and they provide a hard surface for Cladophora to grow on.
     John Berges, a UW-Milwaukee biologist, suggested other relevant factors might include changing wind patterns, water temperatures and currents, and lake levels.
     People have tried many ways to control Cladophora since the 1950s, when it first became a problem on the Great Lakes.  These have included removing it manually with machines, killing it with chemicals, speeding it decomposition with bacteria or fungi, and masking the odor with lime. However, these approaches have been too expensive, impractical, or even counterproductive where they have been tried, reported the DNR Water Resource Management Specialist John Masterson.
     Scientists at the DNR and the UW-Milwaukee WATER Institute are planning more research this summer to better understand the roles of phosphorous, zebra mussels, water clarity, temperature, wind and water currents, and other factors in producing excessive algae.

The proceedings of a Dec. 8 workshop at the WATER Institute for scientists, beach managers and policy makers can be found at www.uwm.edu/DEPT/GLWI/cladophora.