"I am worried that unless we do something, the algae will kill the lake, or at least our enjoyment of it."

Elodea was discovered in Alexander Lake in 2014 by researchers checking minnow traps. At the time, it covered 20 percent of the lake but now has spread to 90 percent.

Elodea, a fast-growing leafy plant, is now in a roadside ditch at the marsh, and a response plan is in the works.

Elodea, an aggressive invasive plant, was discovered this month in the lake used by hundreds of floatplanes, raising fears that it will be spread to multiple sites within flying reach.