What's in the water?
<p>SHAWN GUST/Press A cloudy mass of daphnia, a zooplankton, surfs along the shore of Hayden Lake Tuesday. Residents first sighted the organism last fall.</p>
<p>SHAWN GUST/Press Although annoying and aesthetically displeasing to many who frequent Hayden Lake, the recent concentrations of daphnia that have washed ashore are not harmful to humans.</p>
<p>SHAWN GUST/Press Once dried, daphnia blends with the sandy beaches along Hayden Lake and resembles mud in appearance.</p>
HAYDEN LAKE - The waters of Hayden Lake this summer have been clouded with mysterious black particles floating on the surface, clinging to swimmers and washing up on beaches.
Some have thought it resembles an oil spill on the lake, accumulating wherever the winds and wave action send it. Boaters have spotted it in large bands on the middle of the lake. It grows darkest in shallow areas and near docks.
Some people believed it must be fish eggs, or algae.
Either way, longtime homeowners and cabin goers have said they can't remember it covering the lake and beaches in the past. Many complain about having to shower after swimming.
Kajsa Stromber, a watershed coordinator for the Idaho Department of Environmental Quality in Coeur d'Alene, said tests identified the coffee-ground looking substance as daphnia.
"It's a normal, healthy, wonderful little animal that lives in Hayden Lake," she said. "Daphnia is a really good thing."
As zooplankton, it's a harmless little critter, that can be a good source of food for fish, she said.
"It took a little doing to find out" what exactly it is, she said. "It's nothing that's dangerous to anybody."
Daphnia popped up on the DEQ's radar last summer when people began calling to complain about a possible oil spill on the lake. EcoAnalysts Inc., in Moscow, examined DEQ test samples collected last fall to make an official identification.
The daphnia that appears so abundant now on the lake is in the dormant egg stage, she said.
"If they stay in the right environmental conditions they should be able to hatch later," she said.
Daphnia is hearty in that stage, and should hold up for a while.
Daphnia in the adult stage is almost invisible - to humans.
"The fish have no problem seeing them," she said.
It hasn't been determined why so much of the daphnia is lingering in the dormant, or "resting egg," stage of the life cycle.
"There's probably some kind of stress," she said.
Daphnia is not as digestible to fish in the egg stage, she said.
"We don't know if this is a problem or not," she said. "It may just be a natural occurrence."