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Agriculture Is Changing The Chemistry Of The Mississippi River
New Haven CT (SPX) Jan 31, 2008 Midwestern farming has introduced the equivalent of five Connecticut Rivers into the Mississippi River over the past 50 years and is adding more carbon dioxide annually into its waters, according to a study published in Nature by researchers at Yale and Louisiana State universities. "It's like the discovery of a new large river being piped out of the corn belt," said Pete Raymond, lead author of the study and associate professor of ecosystem ecology at the Yale School of Forestry and Environmental Studies. "Agricultural practices have significantly changed the hydrology and chemistry of the Mississippi River." The researchers tracked changes in the levels of water and bicarbonate, which forms when carbon dioxide in soil water dissolves rock minerals. Bicarbonate plays an important, long-term role in absorbing atmospheric carbon dioxide, a greenhouse gas. Oceans then absorb the excess carbon dioxide and become more acidic in the process. "Ocean acidification makes it more difficult for organisms to form hard shells in coral reefs," said R. Eugene Turner, a co-author of the study and a professor at the Coastal Ecology Institute at Louisiana State University. The researchers concluded that farming practices, such as liming, changes in tile drainage and crop type and rotation, are responsible for the majority of the increase in water and carbon dioxide in the Mississippi River, which is North America's largest river. Raymond said that the research team analyzed 100-year-old data on the Mississippi River, warehoused at two New Orleans water treatment plants, along with data on precipitation and water export. "A notable finding is that changes in farming practices are more important than changes in precipitation to the increase in water being discharged into the river," he said. The researchers used their data to demonstrate the effects of excess water on the carbon content of the river, and to argue that nutrients and pollution in the water are altering the chemistry of the Gulf of Mexico. Community Email This Article Comment On This Article Related Links Yale University Water News - Science, Technology and Politics
Weird Water: Discovery Challenges Long-Held Beliefs About Water's Special Properties Princeton NJ (SPX) Jan 22, 2008 Beyond its role as the elixir of all life, water is a very unusual substance: Scientists have long marveled over counter-intuitive properties that set water apart from other solids and liquids commonly found in nature. The simple fact that water expands when it freezes -- an effect known to anyone whose plumbing has burst in winter -- is just the beginning of a long list of special characteristics. (Most liquids contract when they freeze.) |
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