The single-celled algae that cause 'red tide' produce a potent neurotoxin that can kill marine life, including fish, shellfish, and marine mammals. In a bid to fight back against the bloom, scientists have recently deployed a novel strategy to kill the algae using clay. Known as clay flocculation, the process simply involves spraying the water surface with a slurry of modified clay particles and seawater. Florida red tides are caused by microscopic algae native to the Gulf of Mexico called Karenia brevis. Furthermore, warming waters fuelled by climate change have driven an increase in red tides in recent years.