A Red Tide, or Harmful Algae Bloom (IMAGE) U.S. National Science Foundation Caption A red tide, or harmful algae bloom, is tainting Gulf of Mexico waters off Southwest Florida. Credit NOAA Usage Restrictions None 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.