Red tide is a condition in which a huge area of seawater turns to a reddish-brown hue. This rusty-red discoloration is caused by an exploding population of tiny single-celled microorganisms called dinoflagellates, which are usually found in ocean water but sometimes in lakes and rivers as well. Red tides have occurred naturally since oceans were formed, but today they are becoming more common because of human influence. During summer months, the warm sun and an abundance of food in the water create optimal conditions for the breeding of dinoflagellates, which are a type of phytoplankton. This multiplication, or bloom, happens very rapidly, and the seawater becomes extremely dense with dinoflagellates; sometimes their numbers can reach many millions per cup of seawater. Even though most red tides are harmless, many of them are toxic and extremely dangerous to fish, shellfish, birds, and even humans. Certain species of...