The Nearshore and Offshore Lake Erie Nutrient Study (NOLENS) concludes this month, following a year of research headed by principal investigator Chris Pennuto, a research scientist with the Buffalo State College Great Lakes Center and professor of biology.
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?”
Other Buffalo State team members were Lyubov Burlakova, a research scientist with the center; Alexander Karatayev, director of the center; and Alicia Perez-Fuentetaja, a research scientist with the center and associate professor of biology.
During the 1960s, Lake Erie was considered dead. One of the contributing factors was, ironically, nutrients. “Nutrients are like calories,” said Karatayev. “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.
“When the Clean Water Act was passed in 1972,” said Pennuto, “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,” said Pennuto. “When they wash up on shore in quantity, the beach becomes unusable.”
Several other symptoms show that Lake Erie still isn’t healthy. Avian type E botulism, which sickens many species of wildlife including loons and long-tailed ducks, is present. Harmful blue-green algal blooms occur on the lake’s surface, and they can produce toxins that may be dangerous for humans. A slimy algae that grows on rocks, known as rock snot, is more abundant in the western basin of the lake. The NOLENS study focused on Lake Erie’s central and eastern basins.
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. “We know now that’s not an accurate description of how Lake Erie works,” he said.
Another problem is that the phosphorus doesn’t just disappear. “The bulk of it lies in the sediment,” Pennuto said.
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,” said Pennuto. 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,” Pennuto added. “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.” Studies repeatedly have shown that keeping the water supply clean is the most cost-effective way to ensure a reliable supply of safe water. Treating polluted water to make it clean is much more expensive, and raises the cost of water to consumers.
Karatayev said, “Besides all the water-quality issues, Lake Erie is in our back yard. I want our back yard to have a clean lake where I can swim and fish and water ski.”
Source: prnewswire, July 2, 2010