Great Lakes Environmental Directory Great Lakes Great Lakes environment Great Lakes grants exotic species water pollution water export drilling environment Great Lakes pollution Superior Michigan Huron Erie Ontario ecology Great Lakes issues wetlands Great Lakes wetlands Great Lakes Great Lakes environment Great Lakes watershed water quality exotic species Great Lakes grants water pollution water export oil gas drilling environment environmental Great Lakes pollution Lake Superior Lake Michigan Lake Huron Lake Erie Lake Ontario Great Lakes ecology Great Lakes issues Great Lakes wetlands Great Lakes Resources Great Lakes activist Great Lakes environmental organizations Great Lakes Aquatic Habitat air pollution alien species threatened rare endangered species ecological Great Lakes information Success Stories Great Lakes Directory Home/News Great Lakes Calendar Great Lakes jobs/volunteering Search Great Lakes Organizations Take Action! Contact Us Resources/Links Great Lakes Issues Great Lakes News Article About Us Networking Services

Great Lakes Article:

Enlarged environmental 'dead zone' ripples across Lake Erie
By Dan Vergano

Cleanup efforts starting in the 1970s rebuilt the quality of the lake water, polluted for decades by industries lining the Great Lakes. But within the past decade, monitors have witnessed an increasingly large region of low-oxygen water - dubbed the "dead zone" by the Environmental Protection Agency - in the lake's central basin every year during the late summer.

Last month, environmental officials and scientists from a consortium of universities sampled lake water and sediments, part of a two-year, $2 million study aimed at unraveling the mystery behind the growing zone.

The zone - a 10-foot-thick layer of cold water at the bottom, 55 feet deep in this area - stretches 100 miles across the lake's center and now lasts the entire month of August, up from two weeks a decade ago. The oxygen-poor water kills fish and microscopic creatures that support the lake's food chain.

"It was tremendously surprising" when the enlarged dead zone appeared a decade ago, EPA scientist Paul Bertram says, because pollution controls were improving water quality. "We're trying very hard to understand what has changed."

In addition to triggering foul-smelling water and killing fish that wash up and litter beaches, the zone could create problems that include decreased sports fishing and higher water and sewer rates.

"Bad for people, bad for fish and even bad for birds," says geologist Gerald Matisoff of Case Western Reserve University in Cleveland.

It is thought to have multiple causes. Among them:

Zebra mussels, an unwanted foreign species carpeting the bottom of the lake, may be a key culprit, Matisoff and others suggest. Efficient lake-water filters, mussels may be sucking up oxygen in the water and triggering algae blooms. Algae blooms pull even more oxygen out of the water.

Undetected phosphates from fertilizers may be making their way into the lake, says scientist Dave Culver of Ohio State University. Storm sewers could be depositing phosphates into the lake as well as some smaller, unmonitored rivers. Phospates also trigger algae blooms.

"A naturally occurring cycle could be at work, one somehow worsened by still-undetermined climate changes or other lake rhythms, although core water samples show past dead zones were much smaller," Culver says.

"Nature has a way of dealing with imbalances," Matisoff says.

Help could come from another invasive species, the round gobie fish, which like to dine on zebra mussels.

"It's not like this is the end of Lake Erie," Culver says. Lowering phosphates, whether triggered by pollution or zebra mussels or both, should reduce the dead zone's severity, he says. "If we don't, it's definitely going back to the way it was in the 1970s."

This information is posted for nonprofit educational purposes, in accordance with U.S. Code Title 17, Chapter 1,Sec. 107 copyright laws.
For more information go to: If you wish to use copyrighted material from this site for
purposes of your own that go beyond "fair use," you must obtain permission from the copyright owner.

Great Lakes environmental information

Return to Great Lakes Directory Home/ Site Map