Profiling a lake's 'nasty' invaders

[Spiel]

Profiling a lake's 'nasty' invaders

Algae, phosphorus, mercury, zebra mussels are among the threats to Lake Erie

 

Tuesday, April 29, 2008

Sonja Puzic / Windsor Star

 

PUT-IN-BAY, OHIO - The Franz Theodore Stone Laboratory on the tiny historic Gibraltar Island in western Lake Erie has hosted generations of students, young biologists and leading researchers for more than 100 years.

 

Nestled among a cluster of other smaller islands near Put-in-Bay, the lab is the United States' oldest freshwater biological field station and the island campus of the Ohio State University.

 

It is also the site of important research that collects sobering evidence of the changes in Lake Erie's ecosystem which could have dramatic effects on both sides of the U.S.-Canadian border if governments and environmental agencies do not commit to more long-term restoration and water management initiatives in the Great Lakes.

 

When Stone lab researchers and staff are not showing school-aged children on field trips how to collect plankton samples from Lake Erie, they are carefully studying the lake's temperature patterns, water levels, sources of pollution and its effects on the numerous species that inhabit the shallowest and warmest of the five Great Lakes.

 

When a Stone lab vessel trawled for fish on a sample collection expedition Monday morning, the net also collected handfuls of zebra mussels or round gobies, just two of the invasive species that have entered the Great Lakes through ballast water from international ships. According to biologists, there are more than 180 invasive species in the Great Lakes.

 

Holding up one of the tiny round gobies, John Hageman, co-manager of the Stone lab, said the fish species have been observed across Lake Erie by the billions.

 

And that's just one of the problems creating "huge changes" in Lake Erie over the last several years, Stone lab director Jeff Reutter told a group of journalists this week as part of a Montana-based Institute for Journalism and Natural Resources program aimed at educating media about environmental issues.

 

Pollutants that cling to lake sediment, the flow of contaminants such as phosphorus and the persistence of aquatic invasive species have wreaked havoc on some parts of Lake Erie, said Reutter, who often works and consults with University of Windsor's Great Lakes Institute.

 

There are also plumes of harmful algal blooms spreading across the southern shore of Lake Erie in Ohio during the warm summer months -- caused by phosphorus dumped into the lake by industries, municipalities, tributaries and agricultural runoff.

 

Although that plume, coming from the largest source of polluted run-off flowing into Lake Erie -- the Maumee River -- tends to concentrate in northwest Ohio, it does not stay there.

 

In fact, recent satellite images show the algae mass moving slowly toward Pelee Island. Ultimately, it could end up in Lake Erie's central basin, sinking to the bottom as the algae die off, Reutter said.

 

The Maumee River is not the only culprit, however. "A lot of nasty things are coming (into the lake) from the Detroit River," Reutter said, pointing to the lake's elevated mercury levels.

 

Reutter said scientists are also still struggling to figure out how to control Lake Erie's dead zone, an oxygen-deprived area devoid of life in the deepest parts of the lake's central basin, created when the oxygen supply is cut off by warmer layers of water near the surface. While some scientists have theorized that the dead zone is a naturally occurring phenomenon, others say that climate change and phosphorus are to blame. As the water level in Lake Erie decreases, the lake becomes warmer, causing concerns about the dead zone's expansion.

 

Although Lake Erie's water levels are not of primary concern right now, Reutter said, that could change as water levels in the upper Great Lakes continue to decrease. Concerns that a hole in the St. Clair River bed and erosion, caused by dredging, is lowering Lake Superior's water levels has prompted a study by the International Joint Commission, part of a larger study on the upper Great Lakes. Preliminary results are expected in July 2009.

 

LAKE ERIE FORUM

 

The fifth biennial Lake Erie Millennium Network Conference at the University of Windsor begins today and runs through Thursday.

 

Numerous scientists, researchers and students will discuss the latest status reports on Lake Erie, including climate change, the lake's dead zone, its fish communities and the increases in phosphorous loading in the lake.

 

The conference is open to the public, but you must register by contacting Natalie Carreau at 519-253-3000, ext. 4758. Visit www.LEMN.org for more information.