Cyanobacterial Harmful Algal Blooms and U.S. Geological Survey Science Capabilities

Abstract

An Algal Bloom may be called harmful because of resulting reductions in dissolved oxygen concentrations, alterations in aquatic food webs, unsightly scums along shorelines, production of taste-and-odor compounds that cause unpalatable drinking water and fish flesh, or the production of toxins potent enough to poison aquatic and terrestrial organisms. Many different types of algae can cause harmful algal blooms in freshwater ecosystems. However, the most frequent and severe blooms typically are caused by cyanobacteria, the only freshwater “algae” with the potential for production of toxins potent enough to adversely affect human health.