Everyone could sigh a breath of relief if the 2011 toxic algae bloom that engulfed 2,000 square miles of Lake Erie had been an isolated event, but sadly that is not the case. Researchers from the University of Michigan and eight other research institutions have put together a paper published in the online journal Proceedings of the National Academy of Sciences, which shows that a confluence of complicated factors contributed to the bright green algae bloom that peaked in October, 2011. Among them are agricultural practices that produce an increase in phosphorous runoff and changing weather related to climate change, both of which are probably here to stay.
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The algae bloom was first brought on by higher than usual precipitation levels in May, 2011, which washed phosphorous-containing fertilizers from the Maumee river basin into the western half of Lake Erie. A total of 6-8 inches was recorded that month, and researchers, who used 12 different digital climate models to predict future rainfall in the region, found that the likelihood of storms that drop more than two inches is expected to double by 2100, Physorg reports.
“The 2011 Lake Erie bloom was composed almost entirely of toxic blue-green Microcystis algae,” writes Physorg.
“Concentrations of mycrocystin, a liver toxin produced by the algae, peaked at about 224 times World Health Organization guidelines, according to the researchers.”
No-till farming that leaves great concentrations of phosphorous fertilizers at the surface of soils will continue to get washed into the lake unless practices are changed, the report warns. Soybean, wheat, grain and corn are all grown in the nearby watershed. Corn is particularly greedy for the dissolved reactive phosphorous (DRP) that is responsible for devastating algae blooms that make the aquatic ecosystem almost uninhabitable.
Map by Michigan Sea Grant