TRAVERSE CITY -- Local efforts to track sources of E. coli bacteria in Grand Traverse Bay are moving in the right direction, research on algae growths show.
Grand Valley State University Professor Rick Rediske and an intern team worked several weeks this summer to scoop Cladophora algae from the knee-deep waters at eight bayside beaches, then tested the plants for E. coli content, he said.
Preliminary research points to elevated bacteria levels in algae at beaches with stormwater or other discharges, such as Mitchell Creek, Rediske said.
"It looks like the bacteria that comes out of the stormwater runoff can get trapped in the Cladophora," said Rediske, who also is conducting similar tests in Saginaw Bay.
"We are finding higher levels where there are stormwater outfalls. Based on what we have seen so far, the E. coli seems to be held very tightly in the near-shore area," he said.
Rediske's $60,000, state-funded study is inspired in part by a series of beach closures in recent years tied to elevated bacteria levels. The Grand Traverse County Health Department, Watershed Center Grand Traverse Bay and Traverse City officials have since teamed with a host of experts to curb the problem believed to be linked to animal feces washed into the water.
The city this spring enacted an ordinance against feeding waterfowl in certain areas of the city, including the shoreline. So far in 2008, there have been no beach closings or swim advisories issued.
Rediske's findings "confirm our suspicions that ... Mitchell Creek and other stormwater pipes that discharge into the bay (as) being a source of the E. Coli," said Andy Knott, Watershed executive director.
The health department and the Watershed will conduct their own state-funded tests for E. coli at 16 locations along East Bay's Mitchell Creek over the next year, he said.
"We will compare what he is finding at the outfall of the creek (to) concentrations as we move up stream to see how those concentrations change," Knott said.
"We are just trying to at this point identify ... the hot spots, then we hope to determine if it is human or animal in origin," said Tom Buss, the county's director of environmental health.
Buss believes research on algae also highlights the importance of limiting use of nutrients such as phosphorous that get into the bay, which promotes algae growth that traps bacteria near shore.
"It is kind of a cumulative effect," he said.
"They wash up on the beach and ... when they have high levels of bacteria in them, it can be hazardous," Rediske said of Cladophora.
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