"Huge Changes" Sweeping Lake Erie - Invasives, Algae, Runoff, Industrial Toxins Taking Toll

[hatrack]

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When a Stone lab vessel trawled for fish on a sample collection expedition Monday morning, the net also collected handfuls of zebra mussels and 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 currently 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 (IJRN) 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 agriculture.

Although that plume, coming from the largest source of polluted runoff 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.

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http://www.canada.com/windsorstar/story.html?id=c93bc013-1130-45fd-bd28-976a43b6374c&k=3267

[Botany]

1. Thanx for the post

Interesting stuff