Great Lakes risk assessment gauges Erie as second-worst
By Spencer Hunt THE COLUMBUS DISPATCH
Toxic blue-green algae and invading species of fish, mussels and plants make Lake Erie the second-most-threatened of the five Great Lakes, behind Ontario, according to a new report.
Researchers with the Great Lakes Environmental Assessment and Mapping Project came to this and other conclusions after spending more than three years collecting data on 34 lake “stressors” that include invasive species, climate change and pollution. The result is a first-of-its-kind computer-generated map of the lakes that paints the biggest problem areas in red.
“I think it’s great to call it a Great Lakes threat map,” said Peter McIntyre, a mapping-project researcher with the University of Wisconsin’s Center for Limnology. McIntyre said he hopes the map will assist officials who award hundreds of millions of dollars in grants each year to help clean up and protect the lakes.
Although no one wants a particular Great Lake to be the “worst,” the one that has that status could attract more money to fight problems. Most of the funding would come from the federal Great Lakes Restoration Initiative, which has spent about $1 billion since 2010.
- Lake Ontario landed its “worst” status because of widespread mercury and PCB pollution, and problems stemming from invasive sea lampreys and zebra and quagga mussels.
Ohio advocates and experts have long argued that Erie is the most-threatened Great Lake. “It’s hard to imagine that any other Great Lake would be in more trouble,” said Sandy Bihn, director of the Toledo-based Lake Erie Waterkeeper advocacy group.
In the summer of 2011, researchers tracked a record-size “bloom” of toxic algae in Lake Erie. The algae, also called cyanobacteria, can sicken people and kill pets. NASA satellite photos snapped in October 2011 showed the algae stretching from Toledo to Cleveland.
Decomposing algae create a vast, oxygen-depleted “dead zone” in the lake. Research indicates that Lake Erie has the biggest dead zone, although a sudden shift in Lake Ontario’s zone is suspected in the deaths of thousands of fish that washed up on that lake’s beaches in September.
- Lake Erie has widespread areas contaminated with phosphorus and nitrogen, which are algae-feeding fertilizers that rains wash off Ohio farm fields.
Erie also appears to lead other lakes in sediment problems from erosion; an invasive shoreline reed called phragmites; and one invasive fish species, round gobies. Zebra and quagga mussels are in Erie but are more concentrated in Lake Ontario.
The formula used by researchers to evaluate the cumulative threat to each Great Lake emphasized five categories: declining water level, rising water temperature, zebra and quagga mussels, sea lampreys and ballast-water dumping by oceangoing vessels, McIntyre said.
Phosphorus and nitrogen pollution, although important, didn’t make the top five, McIntyre said.
Jeffrey Reutter, director of Ohio State University’s Sea Grant program and the Stone Laboratory on Lake Erie, said the development of a threat map would be based on what the researchers felt were the most-significant problems.
“It really depends on the issues you are looking at,” Reutter said.
No matter the rankings, Erie’s combination of problems presents a dire threat to its overall ecology, he said.
Climate change also has harmed the lake, Bihn said. The Great Lakes maps show a large loss of winter ice cover in Erie and in Lake Superior. Ice is important because it helps to slow the warming of the water in the spring and summer.
- “The ice levels are just dropping significantly over time, year after year,” Bihn said. firstname.lastname@example.org