COLUMBUS, Ohio (AP) - Lake Erie is one of the most threatened of the five Great Lakes as a result of toxic blue-green algae and invasive species of fish, mussels and plants, according to a new report.
The Great Lakes Environmental Assessment and Mapping Project concluded that Lake Erie was the second-most threatened of the lakes, behind Lake Ontario.
Researchers with the assessment project spent more than three years collecting data on 34 lake "stressors" - including invasive species, climate change and pollution, The Columbus Dispatch reported on Monday.
Peter McIntyre, a mapping-project researcher with the University of Wisconsin's Center for Limnology, said he hopes the computer-generated "threat map" highlighting the areas with the biggest problems will help officials who award hundreds of millions of dollars in grants each year to help clean up and protect the lakes. Those lakes with the worst status could attract more of that money, which mostly comes from the federal Great Lakes Restoration Initiative.
The new map shows Lake Ontario as the most threatened because of widespread mercury and PCB pollution and problems stemming from invasive sea lampreys and zebra and quagga mussels. But Ohio advocates and experts have argued that Lake Erie is the most-threatened of the Great Lakes.
"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.
Researchers in 2011 tracked a record-size "bloom" of the toxic algae in Lake Erie. Satellite photos that year showed the algae, which produces a nerve toxin that can sicken humans and kill pets and other animals, stretching from Toledo to Cleveland. Rains wash manure, fertilizers and sewage into the lake, contaminating widespread areas with nitrogen and phosphorus that feed the algae.
Lake Erie appears to lead other lakes in sediment problems from erosion and in invasive shoreline reeds called phragmites and the invasive round goby fish, although zebra and quagga mussels are more concentrated in Lake Ontario, according to the map.
Researchers evaluated the cumulative threat to each Great Lake, emphasizing the categories of declining water level, rising water temperature, zebra and quagga mussels, sea lampreys and ballast-water dumping by oceangoing vessels, McIntyre said.
But no matter its ranking, Lake Erie's combined problems present a dire threat to its overall ecology, according to Jeffrey Reutter, director of Ohio State University's Sea Grant program and the Stone Laboratory on Lake Erie.
Lake Erie also apparently has been harmed by climate change, with maps showing a large loss of winter ice cover in Erie and in Lake Superior.
Ice helps to slow warming of the water in the spring and summer, and Lake Erie's ice levels are "dropping significantly over time, year after year," Bihn said.