Region 8

Didymosphenia Geminata

Didymosphenia geminata, commonly referred to as "didymo", is a freshwater microscopic diatom. It is found in streams and rivers in much of North America. Didymo increasingly poses a threat to aquatic ecosystems because it forms extensive mats on stream beds. Didymo attaches to the streambed by a stalk. These stalks have a rough texture similar to wet wool and mimic strands of toilet paper, as opposed to other algal species which feel "slimy".

Prevent the Spread:

Decontaminating equipment between uses in different freshwater systems is important to prevent the spread of didymo. Hard copies of the flyer available upon request.

Recommendations for Response:

Didymosphenia geminata is expanding its geographic range. Historically, this diatom occurred mostly in northern latitudes in low nutrient waters; now it occurs in more nutrient-rich water and at lower latitudes.