Lake Erie buried by out-of-control algae; Researchers warn it could become ‘toxic’

Science Recorder | Rick Docksai | Monday, April 01, 2013

Overgrowth of algae holds harmful consequences for people, plants, and animal life all across Lake Erie, warns a study published by the National Academy of Sciences.

The study, one of the most comprehensive reports released on the issue, blames a confluence of farm runoff, weather changes, and invasive new plankton-eating species with enabling algae growth in the lake region to swell to monstrous and unhealthy proportions. According to Anna Michalak, a study co-author and researcher at the Carnegie Institution for Science at Stanford University, the situation will only grow worse, absent serious action on the part of the lake community.

The report come as Erie’s waters have exhibited algae “blooms” every year, but as the study notes, 2011 set a dismal new precedent: A bloom reached 2.5 times the size of any prior bloom on record, turning the western lake green and coating the shore lines with thick algae mats.

Researchers say fertilizer runoff is a major factor. Over the past several years, regional farmers have increased the use of fertilizer, according to the study, and they have been applying it earlier in the season to the bare ground. Additionally, they have been cutting back on tillage, the practice of working the fertilizer into the soil. The confluence of the changing practices have led to more fertilizer seeping from the farmland into the lake, where it feeds the growth of algae populations.

Compounding the runoff effect is unusually severe rainfall, which hit the region in 2011, plus warmer-than-average temperatures and little wind to mix the water up. The heavy rains washed extra fertilizer into the lake, and the warmer temperatures and relatively still waters made for prime conditions for faster algae growth.In addition, the lack of heavy winds — which drives algae to the bottom of the lake – provided the algae with a unique environment in which it could thrive, said reserachers.

The study’s authors expressed further concern over the particular type of algae that the farm runoff is feeding in the lake: cyanobacteria. When cyanobacteria blooms grow in a body of water, they consume so much oxygen that they asphyxiate fish and create “dead zones.” Some cyanobacteria also poison people. Microcystic, the cyanobacteria strain that predominated in the 2011 Erie bloom, produces a deadly liver toxin, and tests of Erie’s water at the time found the concentrations of the toxin to be 200 times higher than the levels that the World Health Organization deems safe.

Not helping matters, invasive species of zebra mussels and quagga mussels have been eating large quantities of the lake’s phytoplankton. Under normal conditions, the phytoplankton compete with the cyanobacteria and keep them in check.

Patterns of climate change, furthermore, do not bode well for the Erie region and its algae problem. The study authors note that climate patterns are trending toward larger spring storms, warmer temperatures, and reduced wind circulation. Much of the climate change may at this point be inevitable, the authors said, but the region’s farmers can and should change their farming methods to significantly reduce fertilizer runoff.

The lake, once considered an environmental success story, remains integral to the region’s commercial success. In the 60s and 70s, the U.S. government, working in coordination with the Canadian government implemented the Great Lakes Water Quality Agreement. The agreement limited the amount of nutrient loading and for the next twenty years it kept algae levels in check. However, in the early 90s, algae levels began to slowly rise again

The change could have significant economic impacts for states relying on the lake, For example, according to Ohio estimates, an estimated 450,000 people fish in the Ohio waters of Lake Erie every year, contributing $680 million to the state’s economy. The lake supplies drinking water to 13 million people in the greater region and roughly three million Ohio residents, and each year more than seven million people flock to Ohio’s portion of the Lake Erie basin. Lawmakers in the state have come under pressure to pursue remedies that appease both farmers and local residents in recent months. Ohio Lake Erie Commission, the state’s premier policy board for the lake, has already put forth a number of recommendations, while lawmakers have faced criticism by interest groups who say progress have been undone by years of neglect.

Lake Erie buried by out-of-control algae; Researchers warn it could become ‘toxic’ | Science Recorder