Algae problem has many roots
By Martha Shad
Gannett Wisconsin Newspapers
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,
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
"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,
"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."