Filamentous algae blooms alter river ecosystems without disrupting overall function

Algae is ubiquitous in waterways around the world, including western North America. Slippery green epilithic algae are a familiar sight on river rocks. Toxic blue-green algae – cyanobacteria – is a visually interesting, but worrying phenomenon. The increasingly widespread filamentous algae, with its long, voluminous green strands, completes the picture and raises new questions for scientists, recreationists and land managers.