Toxic Green Algal Blooms (IMAGE) Florida Atlantic University Caption Commonly known as red tides, brown tides and green tides, blue-green algae or cyanobacteria, like Microcystis, are considered harmful algal blooms and can have severe impacts on human health, aquatic ecosystems and the economy. Credit Bob Hogensen, Martin County, Florida Usage Restrictions Credit: Bob Hogensen, Martin County, Florida License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.