According to enotes red tide is a condition where the sea appears to be a reddish-brown color.
"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 occasionally in lakes and rivers as well."
Follow the link below to learn more, and thank you for using enotes!
Red tides are caused by an explosive growth and accumulation of certain microscopic algae, predominantly dinoflagellates, in coastal waters.
Red tide is actaullly a result of algal bloom..Also anthropogenic factors like pollution and natural factors cause red tides!