Researchers Trace ‘Rock Snot’ to Native Species

[7th, May 2014] Researchers from Canada and Dartmouth University have found that rock snot – a globulous bloom of algae that blossoms in some freshwater riverbeds – more likely stems from changing environmental conditions and global warming, rather than the accidental introduction of new species… or the emergence of new genetic strains, as has been previously theorized.

The findings have real implications: The algae, officially known as Didymosphenia geminate, or “didymo” for short, poses a threat to salmon and trout by affecting the insects the fish eat. Groups have sought to clear the growths through multimillion dollar eradication efforts that harness chemicals and fishing restrictions, but the Dartmouth findings suggest that the solution may in fact lie in mitigating other environmental factors.

“Correctly identifying an invasive species as either native or nonnative is important for developing sound policy, management and scientific research programs because effective responses depend on knowing whether the species’ dominance is caused by ecological or evolutionary novelty, changes in environmental conditions that facilitate it, or both,” Professor Brad Taylor, the study’s lead author, said in a statement.

Rock snot blooms have been recorded as long as a century ago, yet “this information was either ignored or the idea of a new genetic strain was adopted,” Taylor said.

Algal blooms are often caused by excessive levels of phosphorous or other nutrients in freshwater, yet rock snot actually appears when the amount of phosphorous is low.

Here’s why: Didymo lives on the river bottom and draws its nutrients from the water above. When those nutrients are rare, the didymo produces long stalks that push higher into the water. The stalks then cause thick mats to cover the river bottom.

“The idea that low phosphorus can cause an algal bloom is hard for people to accept because we are all taught that more nutrients equal more algae,” Taylor said.

The study, carried out by researchers from both Dartmouth and Environment Canada was published Wednesday in the journal BioScience.

View original article at: Researchers Trace ‘Rock Snot’ to Native Species

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