Red Tide (Alexandrium tamarense)
Red tides occur when environmental conditions allow certain types of algae to multiply so rapidly that they end up tinting the water! (Although algae come in a variety of colors, algal blooms are typically caused by reddish organisms). While in many cases blooms are not harmful, Alexandrium tamarense produces a neurotoxin that can kill. Initial symptoms include tingling, numbness, and a burning sensation of the lips and tongue. As the poison progresses, a rash, loss of motor control, behavioral changes, difficulty breathing, and, without treatment, even death can occur.
In addition, the algae can deplete oxygen supplies in the water, block sunlight, and mortally interfere with both the feeding and filtration processes of small marine life. The consequences can be felt all the way up the food chain.
In fact, some academics believe that the first of the 10 plagues in the Old Testament may have been a red tide! “...And all the water that was in the Nile turned to blood. And the fish in the Nile died and the Nile became foul.” They speculate that the death of frog-egg-eating fish allowed frogs to proliferate; when the abundance of frogs died of starvation, gnats and flies flourished, which brought disease, etc. – though whether the algae can be credited with a hailstorm, no one knows.