Scientists see trouble ahead for big lakes
Written by Muskegon Chronicle   
Wednesday, 30 May 2007 11:30

The Great Lakes have made a dramatic recovery since the 1950s but face new, vexing problems that are fundamentally changing the world's largest source of fresh surface water.

That was the message delivered Monday by longtime researchers meeting at Penn State University for the International Association for Great Lakes Research Conference. The 50th Conference on Great Lakes Research gave scientists a chance to reflect on the state of the lakes -- past, present and future.

"Are the Great Lakes going down the toilet? I don't think so, but there are many great challenges in the future," said David Jude, a research ecologist at the University of Michigan. The current condition of the lakes is best described as a "mixed message," according to Jude and several other researchers at the conference.

Pollution controls implemented in the early 1970s have dramatically improved Great Lakes water quality and government agencies have been able to control one of the worst exotic species, the sea lamprey. As a result, contaminant levels in fish and wildlife have decreased and the lakes now support a $4.5 billion fishery, according to government data.

A less tangible improvement has been the public's changing attitudes about the lakes, said Alfred M. Beeton, the retired director of the National Oceanic and Atmospheric Administration's Great Lakes lab in Ann Arbor. "More and more, we're becoming aware of what a treasure these lakes represent," Beeton said.
Despite the improvements, serious environmental problems are brewing below the surface of the lakes, Jude said.

A growing list of invasive species, many imported by ocean freighters, have fundamentally changed the lakes' ecosystem and plunged the massive water bodies into a state of ecological chaos, scientists said. Zebra and quagga mussels have nearly eliminated diporeia, a freshwater shrimp that fish eat, from Lake Michigan and Lake Superior, according to government data.

The diporeia population in Lake Michigan dropped by 94 percent between 1995 and 2005, said Tom Nalepa, a researcher at NOAA's Great Lakes laboratory. Scientists believe quagga mussels, the tougher cousin of the zebra mussel, are hogging tiny particles of food near the lake bottom that diporeia need to survive.
"There's a tremendous shift in the living biomass taking place on the bottom of Lake Michigan," Nalepa said.

In some areas of the lake, quagga mussel densities are as high as 16,000 mussels per square meter. That doesn't bode well for fish in the lake because the mussels are taking a big bite out of the lake's food chain, Nalepa said. Even more alarming in recent months has been the spread of a fatal fish disease known as VHS, viral hemorrhagic septicemia. Likely imported to the Great Lakes by an ocean freighter, VHS has killed thousands of fish from 20 different species in four of the five Great Lakes; it was confirmed last week in a dead fish taken from Lake Michigan, near Milwaukee. Carlos Fetterolf, retired executive director of the Great Lakes Fishery Commission, said problems caused by exotic species deserve far more attention from federal agencies. He said the amount of federal funds dedicated to fixing and protecting the Great Lakes pales in comparison to the billions being spent to restore the Florida Everglades and Chesapeake Bay.

"If Florida can convince Washington to act on the Everglades' plight, and Virginia and Maryland have convinced Washington of Chesapeake Bay's plight, eight states should be able to work together to convince Washington of the Great Lakes' plight and get real results," Fetterolf said. Jude and other scientists at the conference said it is often difficult to persuade government agencies to work on Great Lakes issues until researchers can prove a human health threat.

The U.S. and Canadian governments, for instance, have yet to stop the flow of exotic species entering the Great Lakes in ocean ships even though research has found thousands of viable organisms and potentially deadly bacteria -- including cholera and cryptosporidium -- in freighters' ballast tanks. Jude said it would take a public health crisis to solve the ballast water controversy.

"Once we get a cholera epidemic in Chicago and it kills 200 people, then we'll deal with ballast water," Jude said.



 
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