Noxious algae blooms are attacking Lake Erie, a problem likely exacerbated by global warming and one that will probably continue unless action is taken, according to a new study.
The researchers who created the study, published in the Proceedings of the National Academy of Sciences, used computerized climate models to predict the likeliness of rainstorms that contribute to the algae blooms, such as the one that occurred in 2011. They found that spring storms that drop over 1.2 inches of rain will likely double in frequency in the region by the end of the century.
"The models do predict an increase in extreme springtime precipitation events, and that's driven by an increase in greenhouse gases," Associate Professor of Atmospheric, Oceanic and Space Sciences Allison Steiner said.
In the summer of 2011, a large algae bloom coated the surface of Lake Erie. At its height, it was about 2.5 times larger than any bloom in Lake Erie previously recorded. According to Ann Michalak, study co-author and researcher at the Carnegie Institution for Science at Stanford University, a number of factors contribute to such blooms.
One is agricultural practices, whereby fertilizer run-off from the nearby area enters the lake, encouraging the growth of algae blooms. The spring storms of 2011 contributed to the bloom that summer by washing the fertilizer away. Strong winds also were not present to keep the lake from being mixed, a process that causes algae to sink to the bottom of the lake. Climate change could exacerbate these problems, creating stronger storms, warmer temperatures and less strong winds.
Aside from being ugly (the blooms coat the water with a nasty green), the algae blooms pose a risk to both the lake's wildlife and people in the surrounding area. Fish find themselves in "dead zones" caused by excessive oxygen consumption by the algae. Thousands of dead fish are now appearing on the coast of Lake Erie near Buffalo, though it has not been stated whether it is related to the algae blooms.
In terms of a human danger, Microcystis, the major type of cyanobacteria found in the 2011 bloom, produces a harmful liver toxin. According to the researchers, levels of Microcystis in Lake Erie's surface were up to 200 times beyond the limit that the World Health Organization deemed acceptable.
This and other events lead to the question of whether algae blooms will be an ever-increasing destructive problem worldwide. Jan Ciborowski, a researcher at the University of Windsor, Ontario, who was not involved in the study, stated that the 2011 bloom "was a significant one in Lake Erie and I agree that it is unlikely to be unique."
So far this year a record number of manatees have died off the coast of southwest Florida due to a red tide, an event caused by blooming of the algae "Karenia brevis." The algae produces neurotoxins that are deadly to fish, sea turtles, birds, marine mammals and, potentially, humans.