If you live near the Gulf of Mexico and you observed an unusual tinge of color in the ocean earlier this month, it wasn’t your imagination. The strange hue was caused by a phenomenon called a “red tide,” and beaches in states from Florida to Texas were closed to protect people from potential health risks.
A red tide is better known in the scientific community as a harmful algal bloom (HAB), and it occurs when there is a large concentration of single-cell plants called algae. Unlike most plants, algae can swim, said Matt Garrett, a research associate at the Florida Fish and Wildlife Conservation Commission’s Fish and Wildlife Research Institute in St. Petersburg.
Different algae species have different structures to help them move. For example, the algae that make up the Florida red tide, a species calledKarenia brevis, has a little whiplike structure that helps them move around in the water, Garrett said. [Marine Marvels: Spectacular Photos of Sea Creatures]