The Latest on Lake Erie's Dead Zones
It was an intense morning of scientific revelations. For four hours, geologists and biologists from 17 universities in the U.S. and Canada presented finding after finding from their summer of research on new dead zones in Lake Erie.
Researchers now believe their old models for understanding the lake's ecosystem are no longer workable. Because sometime in the last decade, Lake Erie began to change.
Bob Heath: We think of complex issues, we realize it may well be complex.
Bob Heath is a geologist from Kent State University. He's one of dozens of scientists on both sides of the border who are members of the Lake Erie Millennium Network. In the summer of 2002, this grassroots coalition of U.S. and Canadian researchers spent nearly $2 million of government funding to look at every possible cause of the return of the dead zones.
Bob Heath: What we scientists are always trying to do is get the picture right, because it's that picture that drives our approaches to management decisions.
Over the last decade, that picture has changed. Scientists first discovered dead zones in the 1970s, when Lake Erie was literally dying from too much of the nutrient phosphorus. The phosphorus fed algae blooms, which ate up all the oxygen at the bottom of the lake, leaving anoxic or 'dead' zones, where fish can't breathe. Federal officials like Ohio Senator George Voinovich voted major funding to reduce the phosphorus load from point sources such as sewage treatment plants. By the 1980s projections for lake health were improving. It was anticipated that Lake Erie would reach a nutrient balance by the last decade of the century. But that's not what happened.
Jan Ciborowski: When zebra mussels arrive, people were yelling that, oh, we're running out of walleye, we're running out of perch, everything's starving, let's open the sewage treatment plants up and get more phosphorus in. And the scientists said, well, it's not that simple.
It certainly wasn't. Jan Ciborowski is a researcher from the University of Windsor and one of the co-directors of the Lake Erie Millennium Network. He says in the mid-1990's, dead zones began to mysteriously reappear in the Central Basin of the lake. And they've been gaining ground ever since.
Dave Rockwell: Pretty much 70% of the basin had, at one time during last year, had anoxic conditions.
In other words, dead zones. Dave Rockwell of the U.S. EPA's Great Lakes Program Office in Chicago was one of the first to notice the changes in Lake Erie. Since the 1970s, both the U.S. and Canada have carefully managed the lake's phosphorus load, keeping point sources like sewage steady. New dead zones meant that phosphorus was increasing. But where was it coming from? One possibility was the late-1980's appearance of exotic zebra mussels and their close cousin, the quagga. Dave Rockwell is one of many researchers who suspect the mussels may be recycling phosphorus.
Dave Rockwell: It does seem to be linked to the exotics coming into the lake.
Recent drops in Great Lakes water levels have reduced the volume of Lake Erie. Canadian biologist Jan Ciborowski says that effectively concentrates phosphorus.
Jan Ciborowski: I really believe that habitat loss and non-point source is a key feature. You know, sedimentation coming in through the rivers, tile drainage, nutrient fertilizer, storm run-off also has nutrients. All those things are un-regulated, they just pile into the lake whenever it rains.
But Ciborowski in not alone in suspecting there have also been changes to internal sources of phosphorus in Lake Erie.
Jan Ciborowski: The last two years in a row we've had incredible storms in October, windstorms... And the last one in October last year washed away 30% of the Detroit River delta. Strewed it all up and dumped it into the middle... Well, that's a huge burst of phosphorus. We don't know what that does in a lake this size.
Data from last summer's research points to other internal sources for the additional load of phosphorus. Among them are the interactions of phosphorus with bacteria, carbon, and heavy metals. This previously-unrecognized complexity makes scientists leery of saying they're ready to answer the question of what's causing the dead zones. Jeff Reutter is a co-director the Lake Erie Millennium coalition. He also heads the Ohio State University's Stone Lab Research Center in Put-in-Bay.
Jeff Reutter: We know a heck of a lot more this year than we did at this time last year. But again, we found a bunch more that we need to work on. We should be providing better science to the decision makers and to the elected officials who need to make these decisions.
But where is the funding for more research on Lake Erie to come from? This year, Senators Mike DeWine and George Voinovich of Ohio have both proposed new federal assistance programs, one through the USEPA, the other with the National Oceanic and Aeronautics Administration. Voinovich says it's time protection of the Great Lakes got some real attention.
George Voinovich: We need to spend the same kind of effort on the Great Lakes that's been spent to restore the Florida Everglades.
Scientists hope a new scientific model for predicting changes in Lake Erie could lead to answers for other important questions like forecasting the health of Great Lakes fisheries. Major funding for that effort may still be some years away, but scientists here are hopeful. In the meantime, they'll continue the work begun last summer as long as local funds last. In Cleveland, Karen Schaefer, 90.3.