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Topics: Environment

Climate Change to Increase Lake Erie “Dead Zones”

By Jim Erickson
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The green scum shown in this image is the worst algae bloom Lake Erie has experienced in decades. (Landsat image created for NASA’s Earth Observatory by Jesse Allen and Robert Simmon, using data provided courtesy of the United States Geological Survey.)

The green scum shown in this image is the worst algae bloom Lake Erie has experienced in decades. (Landsat image created for NASA’s Earth Observatory by Jesse Allen and Robert Simmon, using data provided courtesy of the United States Geological Survey.)

Climate change is expected to increase the frequency of intense spring rain storms in the Great Lakes region throughout this century and will likely add to the number of harmful algal blooms and “dead zones” in Lake Erie, unless additional conservation actions are taken, says aquatic ecologist Donald Scavia. Climate models suggest the number of intense spring rain storms in the region could double by the end of the century, contributing to an overall 30 to 40 percent increase in spring precipitation, Scavia says. He is director of the Graham Sustainability Institute at the University. That increase, combined with the greater availability of phosphorous due to current agricultural practices in the Midwest, means increased amounts of the nutrient will be scoured from farmlands and run into rivers that feed Lake Erie, fueling algae blooms and low-oxygen dead zones where most aquatic organisms cannot survive.”Climate change is likely to make reducing phosphorous loads even more difficult in the future than it is now, which will likely lead to even more toxic algae blooms and larger dead zones unless more conservation is undertaken,” says Scavia.The agricultural practices that contribute to increased availability of phosphorous from fertilizer include no-till farming, a method of planting crops without plowing. The technique reduces soil erosion but also leaves “high concentrations of phosphorous in the upper surface soil, and these intense storms appear to be flushing it out,” Scavia says.The widespread adoption of no-till farming and other agricultural techniques since the mid-1990s have had some positive effects but also appear to have increased the availability of the type of phosphorous, known as soluble reactive phosphorous, that promotes algae blooms, Scavia says.Since the mid-1990s, intense spring rain storms also have become more common in the Great Lakes region, especially in southeast Michigan and northwest Ohio, the regions that provide runoff into Lake Erie, Scavia says.Current agricultural best management practices—such as planting buffer strips around cropland, protecting wetlands, and using less fertilizer—applied at the current scales are likely “not going to be sufficient to reduce the phosphorous loads to the levels we need to prevent the blooms and to get rid of the dead zones,” Scavia says.In the late 1960s, 1970s, and early 1980s, control strategies focused on reducing phosphorous from specific sources, such as waste-treatment plants. Reductions from those so-called point sources led to major gains in Great Lakes health, including a drop in the frequency and extent of harmful algae blooms and dead zones.Some of those gains have been reversed since the mid-1990s. The increased availability of soluble reactive phosphorous and a surge in extreme rainfall events in the region have contributed to a resurgence of both harmful algal blooms and dead zones in Lake Erie, Scavia says.Algae blooms can foul harbors, clog boat motors, reduce fish populations, and can sometimes be toxic to humans.

Jim Erickson

Jim Erickson

JIM ERICKSON is a senior public relations representative at Michigan News, the University's central news service. He was a newspaper reporter at the Rocky Mountain News in Denver, The Arizona Daily Star in Tucson, and the Fort Lauderdale Sun-Sentinel before joining Michigan News in 2007. As a science writer, he won a Science Journalism Award from the American Association for the Advancement of Science, a Science in Society Award from the National Association of Science Writers, and was a Knight Science Journalism Fellow at MIT. Erickson has a master's degree in journalism from Northwestern University and a bachelor's in English from Hamilton College.

COMMENTS

  • Lewis Dickens - 1964

    There should be a distinction between the turquoise and the yellow green colors on the north shore of Ohio.

    The Turquoise colors in Lake St. Clair and the Straights of Detroit have replaced the hideous kahki colors due to effluent controls now in place and certain filtering muscles. The effort to place those controls in place should be lauded.

    It no longer looks like the Cuyahoga river will ignite and burn to the bottom but it is obvious that the Government Agricultural experts must step in.

    Reply

  • c n - 1977

    We need to put a stop to using phosphourous products and ferilizer as soon as possible.

    Reply

  • John Cunningham

    Isn’t it amazing this started again close to the time they started injecting FRACKING WASTE WATER in Ohio at 15,000 + PSI, they’ve caused earth quakes; at that pressure the fluids may have penetrated the soft muck of Lake Erie’s bottom and the biosides and other chemicals have caused putrefaction thus giving this toxic algae a foothold by depleting the oxygen with hydrogen sulfides that biosides in the enviroment can create. THANX jc. E-me

    Reply

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