Winter algae in Lake Erie benefit to food chain

News-Herald

PORT CLINTON, Ohio

When Mike McKay noticed pockets of brown water as a Canadian Coast Guard cutter broke through Lake Erie ice, he assumed mud had clouded the water.

When McKay and other researchers aboard the ship examined water samples, they realized the brown water was filled with a cold-water type of algae.

“To find these massive accumulations is a bit of a surprise,” said McKay, director of Bowling Green State University’s marine program and Ryan professor of biology. “We’re seeing this all across the lake, most abundantly in the Central Basin [which stretches from Sandusky to Erie, Pa.].”

The algae, called diatoms, form long chains and thrive in cold water.

And unlike the toxic blue-green algae that exploded on Lake Erie and inland lakes with a slimy muck during recent years, diatom algae are mostly beneficial to Lake Erie’s food web, McKay said.

The BGSU group first noticed the diatom algae during winter 2007 and since then has seen masses of it throughout the lake during the winter. But that doesn’t mean this is a new type of algae, he said.

Few agencies monitor the Great Lakes during the winter months, so the diatom algae could have been present in Lake Erie long before McKay’s group discovered it, he said. And it has been found in the ocean and in the deepest lake in the world, which is located in Siberia, he said.

“We find it in polar environments associated with sea ice,” he said. “It’s a cold-water species. Once the lake warms up, we don’t find this kind of algae abundance in the water anymore.”

The diatoms appear to form near or with the ice, likely to take advantage of what little sunlight comes through, he said. It’s possible the algae helped form the ice as sort of an anchor to it.

Organisms that eat the algae ultimately become food for larger species, thus providing sport fish such as walleye and perch with a good winter food supply, he said.