WINDSOR — It’s already baking hot on a smoky August morning when Sarah Erickson leans off the side of the dock and dips her tube-shaped monitoring device into the lake.
The water quality specialist for the state health department, who is wearing Chaco sandals and shorts, is sweating under her face mask. The greenish-brownish water of Windsor Lake is warm, too — about 76 degrees near the surface. Erickson is not shocked.
A few blobs of algae float near the dock, but those are the harmless filamentous green variety, not the kind Erickson is concerned about. “It can look gross and smell gross, but that’s not the kind that is going to produce the toxins,” she said. Erickson is looking for blue-green algae, a toxic algae that — in high amounts — can sicken humans and kill animals.
Water scientists call blue-green algae an “emerging contaminant.” They don’t know too much about it yet, other than that it thrives in warm, stagnant water and that Colorado water quality scientists seem to get more calls every year about lakes with green slime or a turquoise film that looks like paint psreading across the surface.
So far this summer, biologists from the state health department and Colorado Parks and Wildlife have detected blue-green algae blooms at Cherry Creek Reservoir in Denver, Prospect Lake in Colorado Springs, Barr Lake near Brighton and Steamboat Lake. The warmer the lakes get, and the more nutrients available to feed the algae, the more prone they are to toxic algae blooms. August and September are typically the worst months.