As the Climate Warms, Toxic Blue-Green Algae Flourish in Lake Erie

The past two weeks did not bring good news to Lake Erie and Ohio’s shores. Our Testing the Waters report last week showed the beaches along Lake Erie were the most contaminated in the nation last year. Now this week, the National Oceanic and Atmospheric Administration  (NOAA) forecasts that dangerous algae blooms are expected to muck up Buckeye waters.  It’s a mess, but might be another sign of the new normal that requires some significant changes in the way we deal with the Great Lakes.

In 2011 Lake Erie saw massive blooms that carpeted 1,600 square miles of its surface. The blooms extended along the entire southern shoreline from Toledo past Cleveland. This year NOAA is predicting that toxic algae blooms will cover about 300 square miles of Lake Erie’s surface. While significantly smaller than the super bloom that occurred in 2011, it still represents a disturbing trend that is influenced by our rapidly warming climate.

Image of Great Lakes in October 2011

This image from 2011 of the Great Lakes shows massive blue-green algae blooms on Lake Erie (bright green areas in the western lake, particularly along the southern shoreline).  Notice the color of the bright green toxic algae blooms in Lake Erie compared to the light blue of the suspended sediments that are visible in the southern portions of Lake Michigan and Lake Huron.

A warming climate may make massive blue-green algae blooms the new normal for summertime on Lake Erie. Blue-green algae thrive in warm waters when there are high levels of phosphorus to feed upon.  On Lake Erie large amounts of phosphorus are released from farm runoff and sewage treatment plants like those in Detroit, Toledo, and Cleveland.  And because Lake Erie is so shallow it warms up quickly – and getting warmer thanks to climate change – making it an ideal cauldron for blue-green algae blooms.   

Blue-green algae, also known as cyanobacteria, secrete neurotoxins, liver toxins, and skin toxins that can cause itiching, rashes, or allergic reactions in healthy adults and exposure can prove fatal to family pets, other animals, and fish. There have been numerous pet deaths around the country attributable to exposure to blue-green algae.  These blooms are not just a nuisance, they are a legitimate public health hazard.

The outbreaks of blue-green algae are a striking example of how climate change is contributing to serious water quality problems.  It’s quite likely that, as temperatures continue to increase, blue-green algae blooms will become more common on the other Great Lakes as well as inland water bodies.  The solution is to cut the nutrient pollution that feeds these toxic algae blooms and cut our carbon dioxide emissions, which are pumping up temperatures around the globe.


More Information on Lake Erie and blue-green algae blooms.

NASA Earth Observatory --  Lake Erie in 2012 and in 2011

New York Times -- Algae Blooms Threaten Lake Erie

National Geographic -- Down the Drain: The Incredible Shrinking Great Lakes

NRDC OnEarth -- Lake Erie Deathwatch

About the Authors

Rob Moore

Senior Policy Analyst, Water program

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