Didymo Mystery Solved

According to research results published in the journal Geophysical Research Letters, the pristine state of unpolluted waterways may be their downfall. A species of freshwater algae that lives in streams and rivers, called Didymo for Didymosphenia geminata, is able to colonize and dominate the bottoms of some of the world's cleanest waterways--precisely because they are so clear. Blooms of Didymo are made up of stalks that form thick mats on the beds of low-nutrient streams and rivers. Didymo has taken over low-nutrient rivers in North America and Europe. Because its blooms alter food webs and have the potential to impact fisheries, Didymo presents a threat to the ecosystem and economic health of waterways.