Didymosphenia geminata: A nuisance freshwater alga
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.
- International fact sheet PDF (1 pp, 2.8 M, About PDF)
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.
- White paper - January 2007 PDF (33 pp, 1.7 M, About PDF)
- Distribution map - Confirmed presence of D. geminata in the United States and Canada PDF (1 pp., 76 K, About PDF)
- A rough field guide for identification
of D. geminata PDF (2 pp. 40K, About PDF)
Events:
- Montana Symposium summary PDF (4 pp, 54 K, About PDF)
- Past events PDF (2 pp, 24 K, About PDF)
- Upcoming events PDF (PDF, 1 pp, 32 K, About PDF)