Controversial theory suggests alga is a native species, not an invader
Environmental change could be triggering “rock snot” algal blooms that harm fish and leave pristine riverbeds looking like tattered mats of soggy toilet paper.
Since the mid-2000s the goopy blooms, which look mucuslike up close, have cropped up in rivers worldwide. Researchers assumed that the responsible alga, Didymosphenia geminata, was a foreigner or a mutant aggressively invading clean watersheds. But a new analysis suggests that the alga nicknamed didymo is instead native to much of the globe, and that changes in water conditions are to blame for a recent boom in blooms. The controversial suggestion could upend strategies for preventing cases of rock snot.