A new study published in the Canadian Journal of Fisheries and Aquatic Sciences suggests that didymo diatoms may already be present in most waters, and that climate change, not human transport, is the primary factor in “rock snot” outbreaks.
According to study leader Michelle Lavery, a graduate student at the University of New Brunswick, ”We can’t make any solid claims as to what the mechanism is that is favoring didymo, but we strongly suspect it has to do with climate.”
“If there’s a bucket of water on the roof left overnight, it will be colonized by diatoms,” Lavery told Live Science. Wind can transport diatoms, as can birds and other animals. In fact researchers found didymo remains in sediments dating back many decades, even where there are no current infestations.
If didymo is no longer considered an “invasive species,” it will change the direction of research. That doesn’t mean that washing waders and boots is no longer necessary–other live organisms can still be transported from stream to stream. But it does force us to re-examine our assumptions about which aspects of human behavior have the greatest impact on the health of aquatic environments.