August 9, 2008

Scientists Worried About Great Salt Lake

The Great Salt Lake is laden with toxic mercury and scientists cannot explain why.

Researchers are now investigating where the poison is coming from and how much danger it poses to the millions of birds that feed on the Great Salt Lake.

"We've got a problem, but we don't know how big it is," said Chris Cline, a U.S. Fish and Wildlife Service biologist.

Cline has been collecting cinnamon teal duck eggs from nests along the shore of the lake and has been analyzing them in the lab.

In 2005, a U.S. Geological Survey test showed that the Great Salt Lake had one of the highest contents of mercury ever recorded in a U.S. body of water.  The state issued warnings about eating certain ducks because of the discovery.

Now researchers are spreading out across the lake for a multiyear study funded by the Environmental Protection Agency.  The initial phase will cost nearly $280,000.

Scientists are trying to find out if the mercury is occurring naturally or if mercury released by coal-fired power plants in the West, mines in Nevada, and developing countries like Indonesia, China, and India is settling in the lake.

Mercury affects birds' ability to fight disease, and causes neurological damage. 
High mercury levels have been found in some Great Salt Lake birds, but it does not seem to be hurting them yet.

"The jury's kind of still out on the impact, but it can't be a good impact," said Tom Aldrich, migratory gamebird coordinator for the Utah Division of Wildlife Resources.

The Great Salt Lake is still a mysterious body of water.  The lake is thought to have covered 20,000 square miles during the last ice age, and was 1,000 feet deep.

Today the lake covers 1,700 square miles, and is saltier and shallower.  Salts dumped by tributaries make the water even saltier than the ocean.

Businesses profit millions of dollars selling tiny brine shrimp, often sold as "sea monkeys," salt, and other minerals from the lake.  The body of water is a popular tourist destination despite its strong foul odor. 
The wetlands and calm water draws many birds, including the world's largest population of Wilson's pharalope, which uses its needle-like bill to eat bugs and shrimp.

More than 9 million birds migrate through the area on their way to Canada or South America.  It's "sort of the Delta airplane hub of the West in terms of migration," Aldrich said.

Scientists say a major problem is that the lakes combination of chemicals and bacteria convert inorganic mercury to a more harmful form called methylmercury. The mercury can get into the brine layer of the lake bottom and work its way into the food chain by infecting shrimp, and then the birds that feed on the shrimp.

If scientists can identify the source of the mercury they can figure out what threat it poses.  They also hope to reduce the amount of mercury in the lake, or control the bacteria that turns it into methylmercury.

Image Courtesy NASA


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