(This article is from the Duluth News-Tribune.)

Crews will wade into Lake Superior and the Twin Ports harbor starting Monday and probably will find high bacteria levels. For the third consecutive summer, some beaches almost certainly will be posted unsafe for humans.

Because some types of bacteria are more dangerous to people than others, there will be a new effort this year, using DNA technology, to determine specifically what's in the water.

If the bacteria originate from birds, for example, it's unlikely to cause as many human diseases. But if it's from people, considered the most serious, the research might help identify the source so it can be shut off.

"We know now that a lot of it (bacteria) in Lake Superior is avian... but some of it is human, too," said Greg Kleinheinz, microbiologist and professor at the University of Wisconsin at Oshkosh. His crews are studying South Shore beaches.

WARNINGS A SURPRISE

The federally funded Great Lakes testing program began in 2003 as interest increased in the rising rate of bacteria-related beach closures. The particles, if swallowed, can make people sick. The bacteria also can cause skin and eye infections.

Since the program started, many people have been alarmed that several beaches on Lake Superior and especially in the Twin Ports harbor have tested positive for bacteria levels that exceed federal safety standards. Some harbor beaches in Duluth, on the bay side of Park Point, have been posted as unsafe much of the past two summers.

There are some patterns when high bacteria levels have been found, including windy days, when bacteria in the sediment may be churned up, and days after heavy rains, when dog feces and other matter on land is washed into the water.

In some areas, heavy concentrations of waterfowl -- gulls, ducks or geese -- have been noticed. A few cases may have been related to sewer overflows or raw sewage illegally funneled into the storm-sewer system or leaking from septic tanks.

It's becoming more clear that there probably isn't just one cause of bacteria outbreaks on local beaches and that solving the problem will take a multitude of efforts, experts say.

Even tracking the DNA from various bacteria has proven difficult because there has been no historic Department of Natural Resources library for possible sources, including all the birds and animals that live near the lake.

In some cases, solutions have been simple. On Lake Michigan in Wisconsin's Oneida County, officials strung fishing line along the beach each evening, effectively keeping gulls and geese from coming onto shore and defecating. That simple move cut beach closures at the site from 24 one year to one the next.

For other areas, it will take more research, more money and hard work to stop the source -- if it's possible at all.

"It's frustrating to us, and I'm sure to the public, because we can't take one sample and say we found the culprit," Kleinheinz said. "This isn't 'Beachfront CSI.' It's not that simple."

Two Seagrant-funded studies by University of Minnesota-Duluth researcher Randall Hicks are looking at harbor bacteria using DNA testing. The first study, now in its second year, is looking at whether E. coli bacteria may be able to reproduce and thrive in the sediment or other parts of the harbor -- without a host animal.

The second study is trying to determine whether Duluth sewage flow elevates E. coli levels, as opposed to animal and bird contributions.

Hicks' 2003 study on North Shore streams found that humans were just a small contributor of the bacteria in those waters, noting that birds and wildlife were much larger contributors of E. coli.

"It becomes a risk issue at that point... Some diseases can cross species barriers. Certainly, we're going to be more concerned if all of the indicator bacteria were turning up as human, though, and that hasn't been the case," Hicks said.

WORST NEAR SHORE

On the Wisconsin side, Kleinheinz's crews from UW Oshkosh have been testing in Ashland, Bayfield and Iron counties, where they've found rural beaches are much different than urban waterfronts.

Rain plays less of a role in raising bacteria levels in remote areas because there's little or no stormwater runoff to carry sewage overflow or dog feces into the lake from parking lots and streets -- a key problem in urban areas.

Kleinheinz also is looking at how bacteria levels change throughout the year. Checking through the ice in midwinter, researchers didn't find any bacteria at beaches. But early results seem to show bacteria levels slowly build throughout summer, with occasional spikes.

"It seems to slowly build up as the season goes on," he said, as new bacteria flow into the water faster than the old bacteria die off.

The problem also seems to be isolated to very near the shoreline. Samples taken in a foot of water show high bacteria levels, while those taken a few feet farther from shore at the same beach usually don't show a problem.

Still, the bacteria issue should be taken seriously. In 2002, 69 people became seriously ill after swimming in Nicolet Bay Beach in Wisconsin's Door County. Had the beach testing program been in place then, warning signs may have been up, and many of those people may not have gone swimming.

The good news so far, Kleinheinz said, is that even where high levels of E. coli have been found on South Shore beaches, no disease-causing pathogens have been found.

"If you see a sign, don't go in," he said. Although there may not be any disease-causing pathogens present, "Why take the chance?

"If there's no sign up, jump in," he said. "Lake Superior is still a very clean lake. If you can tolerate the cold water."