Lake Erie western basin near Detroit as seen recently from outer space (Courtesy NASA Earth Observatory)
Jeff Reutter, Director of the Ohio Sea Grant and Stone Laboratory at Ohio State University, speaking at the State of the Lakes Ecosystem Conference in Erie PA, delivered discouraging news regarding phosphorous content in the lake.
By the 1990’s, phosphorous levels in Lake Erie were only two-thirds of 1970s levels, when it was considered a dead lake. Today, Reutter said levels are now back where they were in the 1970s, and portions of the lake are indeed dead zones.
Run-off from storms and record-setting heavy rains wash the phosphorous into the lake. The chemical is used in fertilizers, detergents and water treatments. The combination of warm water and phosphorous makes the Great Lakes a huge incubator for the algae blooms that foul the water and kill off fish because of low oxygen conditions. Additionally, these anaerobic conditions are favorable for the growth of avian botulism and other bacteria dangerous to humans and animals.
Reutter observed that 2011 had all the ingredients favorable for big algae blooms. Early spring storms filled the shallow basin of the lake with huge amounts of phosphorous. The storms were followed by a long drought that restricted run-off into rivers and tributaries that drain the polluted water.
“Climate change, warming trends, call it what you want,” the Director said. “Storms are getting worse and more frequent, and nutrients are flowing into the water.”
Because Lake Erie is the most southern and most shallow of the Great Lakes, it’s also the warmest and the most susceptible to dead zones. Warmer conditions during winter are also favorable to the flourishing of algae blooms. Ice is forming later in the fall and is thawing earlier in the spring because of temperature changes and lower water levels.
A recent examination of Lake Erie found what appeared to be blue-green algae blooms under the ice in the winter months when most algae and bacteria are usually killed off by the cold.
Despite recent bans of phosphorous in detergents around the Great Lakes, a number of them and the St Lawrence River report an upsurge in algae blooms.
“After decades of studying and reporting, . . . we largely know what the solutions are,” said Cameron Davis, senior advisor with the EPA. “One of the big issues is the increase of algae blooms. We need to double-down on the efforts to reduce phosphorous.”