W. Wash. bay may be producing its own bacteria

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by GARY CHITTIM / KING 5 News

NWCN.com

Posted on July 12, 2010 at 4:51 PM

Updated Monday, Jul 12 at 5:48 PM

SEATTLE - It would normally take them about an hour-and-a-half to drive to Oakland Bay near Shelton, but researchers in Seattle can now study the bay by simply climbing a ladder.

Scientists with Herrera Environmental Consultants have recreated Oakland Bay on the roof of a Seattle laboratory building. Oakland Bay, one of the world's most productive manila clam bays, is suffering from high levels of fecal coliform bacteria in certain areas. 

Scientists brought samples of the bay's seawater and sediment and used two 40-gallon aquariums, some coolers and pumps to simulate Oakland Bay, complete with tides and identical water temperatures. They wanted to study it under laboratory conditions, and it may have worked.

In the past, scientists with commercial growers and the Squaxin Island Indian Tribe concentrated on how to control the bacteria coming in from aging water treatment facilities, septic tanks or nearby cattle farms. But the Seattle team now believes the fecal coliform, which lives in the digestive tract of mammals, has found a new host with a similar temperature and nutrient level.

"We actually think there might be some regrowth occurring in the sediments as they get warm and as the temperatures in the sediments approach those in the gut where fecal coliform grow," explained Rob Zisette, Lead Water Quality Scientist with Herrera Environmental Consultants.

That means the bacteria could not only survive in the sediment, it could breed. Oakland Bay could be producing its own fecal coliform bacteria.

"That certainly changes the equation," said John Konovsky, Environmental Manager of the Squaxin Island Tribe. "The way we normally approach this problem of bacteria in marine water, won't work." 

The good news is fecal coliform has a natural enemy; sunlight. Konovsky hopes clam harvesting methods can be changed to keep the silt down and allow for more sunlight to reach the sediment. It won't be easy but at least, by using a rooftop replica, scientists have a better idea of what they're dealing with in Oakland Bay.

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