Turns out, noses aren’t the only things that get snotty: Phlegm-like algae grosses out stream beds, too. Listen up:

ACHOO! Wash your gear before leaving a stream, because rock snot is pretty contagious! (via David Perez)
“Rock snot,” aka didymosphenia geminate, is an algae that most anyone can identify, thanks to its snot-like appearance.
Although it’s not toxic, fast-growing rock snot can overgrow native algae that insects and fishes in the stream rely on for food. It can also smother the streambed, which in turn can affect the flow of water over fish eggs.
Rock snot is spread from stream to stream on the soles of boots, the bottoms of canoes, or in the bilge of kayaks. Dave Arscott, Assistant Director of Stroud Water Research Center, says once it’s in the water there is no way to remove it, so prevention is key.
“We need to clean, check, and dry our gear as we move from waterway to waterway,” he explains.
Anyone have a waterproof tissue?
Get Schooled:
- Didyaknow these PA Fish and Boat Commission facts about didymo?
- Catch the drips about rock snot via this New York State DEC factsheet
- Learn why It’Snot labeled as invasive anymore, through this article from Scientific American
- Read about global warming, and how it is making rocks sneeze, in this article from National Geographic
The fine print:
- This segment was produced in partnership with Cornell’s Atkinson Center for a Sustainable Future






