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Friday, October 29, 2010

Didymo Confirmed in Remote Chilean Rivers

The invasion of the diatom Didymosphenia geminata, or didymo, has spread to remote Chilean rivers near Esquel, Argentina.

Didymo is a disgusting aquatic invasive species that has hit several regions of the world. It invaded New Zealand in 2004 and has since spread to 32 watersheds there. Didymo, or "rock snot" as it's affectionately called, is a problem because of its propensity to erupt into massive “nuisance blooms” that cover stream and river bottoms. These dense masses can alter the aquatic habitat for other life forms, such as invertebrates and fish, and consequently the health of the entire waterway.  In other words, they choke everything else out.

The presence of didymo was first reported in Lago Sarmiento, Chile, in 1964, but this is the first known occurrence of a nuisance bloom in South America. The newly discovered bloom was reported on Rio Espolon and Rio Futaleufรบ, covering  a total of more than 56 river kilometers.

Didymo is known to survive in damp conditions for more than 30 days and can be transported on the gear of anglers, boaters, kayakers, swimmers and just about anyone or anything that comes in contact with water. The pristine, low-nutrient rivers that anglers, kayakers and vacationers seek are the same ones that are most vulnerable to large blooms of didymo.

Didymosphenia geminata cells produce large amounts of mucilaginous stalks. These stalks are white and look like wet toilet paper when clinging to fishing line. The stalks, cells, and associated sediment can resemble raw sewage lining riverbeds or streambeds.  Rock snot is a most descriptive slang term for the stuff.

Didymo presents a paradox to scientists because it is able to create large amounts of biomass in low-nutrient rivers. Recent work indicates that the amount of stalk produced is related to the phosphorus concentration of the water, implying that the stalk acts to attract and take up phosphorus for the cells. In some regions of the world, the blooms are persistent for a number of years after the initial invasion.

Clean you gear, including boots, waders, fishing tackle, lures, flies, boats, swimsuits and anything that comes in contact with the water.  Visit Protect Your Waters for more information and advise on dealing with didymo and other invasive junk: http://www.protectyourwaters.net/