Monday, September 26, 2011

Nitrate levels rising in northwestern Pacific

Terra Daily: Changes in the ratio of nitrate to phosphorus in the oceans off the coasts of Korea and Japan caused by atmospheric and riverine pollutants may influence the makeup of marine plants and influence marine ecology, according to researchers from Korea and the U. S.

"Normally in a marine environment nitrate is the limiting factor, but increased nitrate in the ocean can spur growth and create a situation where phosphorus becomes the nutrient in short supply," says Raymond G. Najjar, professor of oceanography, Penn State. "This change in nutrients could favor organisms that are better suited for high nitrate and low phosphorus."

According to the researchers, the effects of anthropogenic nitrate pollution from the air have been shown to be significant in local lakes, streams and estuaries in Norway, Sweden and the U.S. "This is the first evidence of increases in nitrate in ocean waters not in an enclosed estuary like the Chesapeake Bay," said Najjar. "These are large, very deep bodies of water and it is surprising to see increased nitrate in these large seas."

...They also compared the amount of nitrogen deposited from the air between 2002 and 2008 for Korea and Japan with the amounts of nitrate in the water during that same time period to show that the increased levels in the water are directly correlated to an increase in human-generated atmospheric nitrogen....

Nakdong River flowing through the region of Andong, South Korea, shot by Theda Grimoire, Wikimedia Commons via Flickr, under the Creative Commons Attribution-Share Alike 2.0 Generic license

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