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Great Lakes Article:

Dead zone detected in Lake Erie
Just when environmentalists were gaining hope, mysterious void emerges in basin's deepest water

Beacon Journal staff writer
09/19/2002

Lake Erie may be dying once again.

A team of American and Canadian scientists aboard the research vessel Lake Guardian is out on Lake Erie trying to determine why its chemistry has unexpectedly changed, creating a large ``dead zone'' in the deepest water of the central basin between Sandusky and Erie, Pa.

Excessive phosphorus in the water -- a condition that existed in the lake in the 1960s -- has left the zone devoid of dissolved oxygen needed by fish and aquatic insects.

Should the phosphorus problem persist, the result could be massive fish kills, damage to Ohio's thriving walleye fishery, a threatened tourist industry, fouled swimming beaches and bad-tasting and bad-smelling drinking water in communities such as Cleveland that draw their water from the lake.

The phosphorus has yet to trigger massive algae blooms that lead to such problems, and scientists don't know why that hasn't occurred. But decaying algae washed up on beaches in Vermilion and Erie last year.

``It's the beginning of the second environmental war on Lake Erie,'' said U.S. Environmental Protection Agency scientist David Rockwell. ``It's a very serious problem, and it could be a really big problem.... The brakes we thought we had on the system aren't working anymore.''

Mussels are suspects

The excessive phosphorus may be caused by zebra and quagga mussels changing the lake, the experts say.

Research is under way by a team of nearly 30 scientists from 17 universities headed by Gerald Matisoff of Cleveland's Case Western Reserve University.

As part of a $2 million, two-year study, the 200-foot Lake Guardian, which is owned by the EPA, is making its third seven-day voyage of the summer. Another trip could be scheduled this fall.

Phosphorus levels have been rising since 1995. Algae has been increasing since 1997, and dissolved oxygen has been dropping to levels that threaten fish, plankton and aquatic insects in the central basin.

If those trends continue for another three years, Lake Erie could face 1970s-style problems, says Lake Erie expert Jeffrey Reutter of Ohio State University.

``That's a bad thing and a bad trend,'' he said. ``It's not the end of the world... but it means we're going to have to devise a new plan to manage the lake.''

Scientists are concerned because everyone had thought the lake was getting cleaner. Then it became apparent that thedecades-old phosphorus problem had reappeared. ``It hasn't improved the way we thought it would,'' said U.S. EPA scientist Paul Bertram.

Scientists fear that the dead zone is a sign that environmental improvements in the lake have been reversed, although they don't understand what's happening or how it's occurring. No one has a remedy for the problem.

Zone appears in 2001

The dead zone surprisingly appeared in 2001 in the 6,300-square-mile central basin. It was the largest such zone to show up in the lake since the early 1980s.

This year, the zone reappeared. At the worst point, in late August, 90 percent of the central basin didn't have enough dissolved oxygen in the deepest waters. Although bad, that was an improvement over a year earlier, Rockwell said.

The zone does not appear in the lake's shallower western end or in the deeper eastern end. It disappears in the fall when the waters naturally mix.

Scientists from the U.S. EPA, Environment Canada and the universities are trying to find the answers to a few key Lake Erie questions:

• Why is there again a dead zone in the summer?

• Why is phosphorus in the water increasing when the amount of phosphorus going into the lake isn't increasing?

• Why is chlorophyll -- an indicator of algae -- at historically low levels? Are the mussels filtering out and feeding on the algae?

``We have tracked Lake Erie for decades and thought we had a good historical understanding of what to expect now and in the future,'' said EPA spokesman Thomas Skinner. ``But the recent discovery of sudden biological changes, which could have long-term effects on the ecosystem, prompted this all-out investigation.''

Research topics

Other topics of research include global warming and ultraviolet light, whether the mussels eat the algae before it blooms into massive floating mats, and whether floating petroleum products could be limiting algae production.

Case Western Reserve's Matisoff said it will probably be late this year before preliminary data from the research is released and next year before the results will be finalized.

Reutter said the lake's oxygen problem appears to be growing.

``We believe it is caused by excess phosphorus,'' he said, ``but we also believe zebra mussels and quagga mussels are having an impact because they appear to alter the way phosphorus cycles through the system.''

Phosphorus from farm runoff and sewage plants is carried into the lake by storm water and rivers. It's a nutrient for algae, which grows, dies and sinks to the bottom to rot. Bacteria feeding on the rotting algae remove needed oxygen from the water.

Past cleanup efforts

In the mid-1960s, national publications, including Life magazine, declared that Lake Erie, filled with blankets of algae, was dead. But the lake wasn't dead -- it was over-enriched with phosphorus.

In 1969, nearly 30,000 tons of phosphorus went into Lake Erie. By the mid-1990s, that amount had been cut to 11,000 tons under a U.S.-Canadian agreement.

An estimated $8 billion was spent to upgrade sewage treatment plants to reduce the amount of phosphorus going into Lake Erie.

In 1990, Ohio banned the sale of high-phosphorus laundry detergents in 32 counties that drain into the lake.

The phosphorus problem appeared to have gone away, only to reappear.

In a congressional hearing in August in Cleveland, Ohio State researcher David Culver blamed the new phosphorus problem on the growing number of quagga and zebra mussels in the lake.

Mussels' waste

Both species release phosphorus as waste, but the quagga, a thumb-sized clam, may be the bigger culprit. It produces more phosphorus than the zebra mussel and outnumbers its cousin in the central basin.

Zebra mussels were found in Lake Erie in 1988, and quaggas were discovered in 1992. The quaggas prefer water at least 30 feet deep, while zebra mussels are found in shallower water.

Both entered the Great Lakes from Europe in freighter ballast water. Such water is used to stabilize freighters and is discharged when ships arrive at their destinations. Ballast water may contain animals and plants from the home port that end up being transported around the world. The United States and Canada now ban ballast-water dumping.

If mussels are determined to be the problem, there is no way to remove them from Lake Erie, Culver said.

The only solution, experts say, would be to curtail phosphorus from farm-fertilizer runoff, from combined sewers such as those in Akron and Cleveland, and from high-phosphorus dish-washing soaps.

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