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Great Lakes Article:

Algae problem has many roots
By Martha Shad
Gannett Wisconsin Newspapers
11/04/05

From Sheboygan to Manitowoc, to varying degrees, the shore is littered with decaying algae.

While itís not an uncommon sight, this year appears to be worse - and although thereís a lot of speculation as to why, no one has any proof.

"There are a multitude of factors involved, but something has changed in the last four or five years for the Cladophora (algae) to express itself," said Karl Klessig, a dairy farmer in Manitowoc County.

Cladophora is a branched, olive-green plant that usually grows up to three feet long, according to John Masterson, water quality biologist with the Department of Natural Resourcesí Plymouth office.

The plant grows in two cycles each year, usually in about mid-July and again in the late fall. Waves detach the algae and push it against the shore, forming mats of gooey, green sludge in places.

Masterson and other experts have a laundry list of things they believe encourage algae growth.

Zebra mussel influence

Algae usually grows in water 4 to 6 feet deep, but lately itís been found in much deeper water and in larger quantities, Masterson said.

Thatís because the water is clearer, thanks to zebra mussels, non-native mollusks first found in Lake Michigan in the early 1990s.

"Zebra mussels filter huge amounts of water to get the microorganisms," said Vicky Harris, water quality specialist with the University of Wisconsin-Green Bayís Sea Grant Institute.

"That filtering makes the water clearer, so more light gets deeper into the water."

Scuba diver Randy Wallander can attest to the lakeís increasing clarity.

"On good days years ago, you could see 10 to 15 feet. This year, you can see 65 feet," said Wallander, a Manitowoc-area resident who has been diving since 1970.

The shell-covered mollusks attach themselves to virtually any hard surface, such as rocks, glass, wood or metal. Theyíll collect in clusters up to about four inches thick, Wallander said.

"One adult filters a quart of water a day," he said. "Theyíve been in the lake for about 10 years and theyíre still expanding.

The last 10 years, the lakeís been getting clearer and the sunlightís penetrating further. I donít know what else would make the algae grow faster or produce more."

Weather also a factor

Algae is moved around by wind and waves. So when a storm moves across the lake, the algae is torn loose and eventually winds up on or near the shore, Harris said.

Even winter can stimulate algae growth.

"If the lake doesnít ice over in the winter, more water evaporates than during the summer because the air is so dry it sucks the water up," Harris said.

The loss of water means the sun doesnít have as far to go to reach the algae, she said.

Lake currents also may play a role.

There are two shallower areas in the lake - the Two Rivers ridge and the Mid-Lake Plateau - that separate the water circulation into distinct counter-clockwise motions north and south of the formations, Harris said.

That may cause the water to be less active than in other areas, Masterson said.

"Generally, the current along the shore is north to south," Harris said. "But, that changes depending on how storms track, the direction of prevailing winds and wind speeds. There is some indication that the lakeís currents may be shifting."

Additionally, there is a vertical thermal barrier between the near- and offshore waters that keeps the two from mixing, Harris said.

Phosphorus a culprit

Phosphorus comes from agriculture and non-agricultural sources such as private homes and nature. There are two forms, soluble and non-soluble, Masterson said.

"Non-soluble almost always attaches to soil," Klessig said. "Soluble gets into the water when plants die and deteriorate. The phosphorous is released from the decomposition. It gets into rivers with snow melt and rain water."

Experts agree that phosphorus contributes to the algae problem, but some people, like Garth Hammond and Ron Schaper, think it is the primary problem.

Schaper, who has lived on Lake Michigan for 30 years and has sailed its waters for most of his 59 years, began researching the algae problem several months ago.

He hiked the lakeshore from Sheboygan to Manitowoc. The excessive amounts of algae that he saw prompted him to call the Department of Natural Resources.

"No one had any answers, but they also didnít know it was this bad," Schaper said.

Hammond and his neighbor, Wayne Schuette, underwent extensive training at the University of Wisconsin-Stevens Point to learn how to correctly test river water because they were convinced the problem stemmed from excess phosphorus generated by farms, Hammond said.

To prove their theory, the pair took samples from Fischer and Point creeks in May and July. Normal phosphorus levels are 0.01 milligram per liter. The results from their samples ranged from a low of 0.14 to a high of 0.91, Hammond said.

"Iím not an expert, but I suspect that most of the phosphorus comes from the farms," Hammond said.

Klessig, the Manitowoc dairy farmer, agrees that despite their best efforts, farmers canít prevent some phosphorous from escaping into rivers and lakes.

But he wants more information on how much of the phosphorous actually comes from farms.

"The important question to consider is, what type of phosphorus is in the river and lake water and where does it come from? Then, if it comes from ag, what can ag to do minimize runoff?" he said.

Klessig said new agriculture rules require farmers who grow any type of crop to implement a phosphorus-based nutrient management system by 2008.

"Most farmers use minimum tilling and do a good job of trying to control soil erosion," Klessig said. "I feel thereís a lack of understanding of how phosphorus moves through the environment, (and) as a result, itís easy to point a finger. The issue is very concerning to everyone, whether youíre in ag or not."

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