Some of the world's cleanest waterways may be in trouble for being so clean.

A species of fast-growing freshwater algae that lives in streams and rivers - sometimes called "river snot" - can alter food supplies to other aquatic life and hurt fisheries, according to a new report published in the journal Geophysical Research Letters. The study was funded by the National Science Foundation and the State of South Dakota Carbon Scientist fund.

'River snot' could damage pristine waterways, study finds – This Just In - CNN.com Blogs