[Odonata-l] Didymosphenia geminata

[Bryan Pfeiffer]

Sorry, not Didymops. Nor Enallagma geminatum.

Didymosphenia geminata is an invasive diatom recently discovered in 
the Connecticut River. It can bloom into horrific algal mats on 
rivers and streams. And I gather it is easily spread by people, 
including odonatologists. This may be old news to folks in the 
western states, but it's brand new here in New England.

Vermont and New Hampshire have sprung into action to contain 
Didymosphenia, which also goes by the nicknames Didymo or Rock Snot. 
We're all cleaning our gear before switching sites and waterways. 
(Clean with, by volume, 2% bleach or 5% dish-washing detergent or 
salt, with contact for at least one minute; give your water-absorbent 
gear a good soaking.)

Those of us travelling to Arizona this week for the DSA meeting (or 
anywhere else, for that matter) would be well-advised to clean gear 
so as not to spread this stuff. Didymosphenia can remain viable for 
days in moist conditions; and it's reported that a single cell may be 
enough to colonize a new site.

Here's some information, including a distribution map and a white 
paper that reports:

"This diatom is able to dominate stream surfaces
by covering up to 100% of substrate with thicknesses
of greater than 20 cm, greatly altering physical and
biological conditions within streams."

http://www.epa.gov/region8/water/didymosphenia/

-Bryan Pfeiffer

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Bryan Pfeiffer

Wings Environmental
113 Bartlett Road
Plainfield, VT 05667

www.WingsEnvironmental.com
www.VermontBirdTours.com
www.WingsPhotography.com
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