Thursday, July 1, 2010

Study Explains Why Lake Erie's Health Is Still Bad

Jun 30: The Nearshore and Offshore Lake Erie Nutrient Study (NOLENS), undertaken by Buffalo State College Great Lakes Center and under the direction of principal investigator Chris Pennuto, a research scientist with the  and professor of biology, concludes this month following a year of research. The fundamental question of the study was, "Why didn't Lake Erie's health improve as expected when the amount of phosphorus discharged into the lake decreased?"
    During the 1960s, Lake Erie was considered dead. One of the contributing factors was, ironically, nutrients. A release indicates that, "Nutrients are like calories. You need calories to live, but if you eat too many of them, you can get very, very sick." One of the nutrients is phosphorus. Pennuto said, "When the Clean Water Act was passed in 1972, one of its goals was to reduce water pollution enough to meet certain 'swimmable and fishable' criteria. A specific target goal was to limit the amount of phosphorus discharged into Lake Erie at 11,000 tons a year. Even though that goal was reached more than a decade ago, the lake continues to exhibit some symptoms of illness. Huge algal mats still cover much of the lake bottom, and they shouldn't be there. When they wash up on shore in quantity, the beach becomes unusable."
    During the one-year project, the NOLENS team took more than 500 water, sediment, and tissue samples, which enabled them to look at all the major pools of nutrients in plants and animal smaller than 4 cms (1.6 inches) in size. All told, about 2,500 sample tests were run. In explaining why achieving the target of 11,000 tons of phosphorus didn't yield the expected benefits, Pennuto explained that the models used by scientists in the 1970s looked at the lake as if it were "a big bathtub," in which everything would be mixed up evenly. He said, "We know now that's not an accurate description of how Lake Erie works."
    Another problem is that the phosphorus doesn't just disappear. Pennuto said, "The bulk of it lies in the sediment. The lake's sediment doesn't stay put, so the phosphorus that accumulates there is continuously recirculated throughout the lake. There are biological and chemical processes that distribute it back into the water. The sediment also can be disturbed by human activity, such as dumping dredged material in the lake. The environment provides all kinds of services we don't get charged for. The cheapest way to have clean water is to keep the water sources healthy, because healthy lakes clean themselves. As human beings, we're made up mostly of water, so it is in our interest to make sure it is clean."
    Access a release from BSC Great Lakes Center (click here). Access the BSC Great Lakes Center website for more information (click here).

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