Volume 18 Issue 46
Roll – Crimson Tide – Roll, may or may not be your favorite shout at College football games, but if you are a fisherman, sportsman, beachgoer or other visitors to coastal waters where the dreaded Red Tide occurs, it can certainly bring an unwanted experience.
Red tides occur worldwide in oceans, bays, intertidal zones, and are most commonly caused by the upwelling of nutrients from the sea floor caused by massive storms, though anthropogenic causes such as urban/agricultural runoff may also be a contributing factor. During these upwellings, certain species of phytoplankton and dinoflagellates can multiply rapidly. These organisms contain pigments that vary in color from brown to pink to red and discolor the water and hence the name Red Tide. In the gulf coast region of the United States, the most common species causing Red Tides is Karenia brevis, one of many different species of the genus Karenia found in the world’s oceans. The northeast coast of the United States experiences Red Tides caused by another species of dinoflagellate known as Alexandrium fundyense. The growth of these algal blooms depends on wind, temperature, nutrients, and salinity. Red Tides do not occur in freshwater ecosystems. The occurrence of Red Tides in some locations appears to be entirely natural and is a seasonal occurrence resulting from coastal upwelling and the movement of certain ocean currents.
Red tides are often associated with fish kills from the algal production of toxins such as brevotoxins and ichthyotoxins that are harmful to marine life. These toxins can build up in shellfish that are then eaten by other animals. Fish typically exhibit neurotoxin poisoning by swimming in irregular spasmodic motions followed by paralysis, difficulty breathing and death.
Brevetoxins are tasteless, odorless, and heat and acid stable. Thus, these toxins cannot be easily detected, nor can they be removed by food preparation procedures. Humans can be affected by the Red Tide by eating contaminated shellfish, breathing winds that have become aerosolized, and sometimes by skin contact. People who eat contaminated shellfish may suffer from severe gastrointestinal and neurologic symptoms including vomiting, nausea, slurred speech. tingling lips, fingers or toes. Swimming among brevetoxins or inhaling brevetoxins dispersed in the air may cause irritation of the eyes, nose, and throat, as well as coughing, wheezing, and shortness of breath. People with respiratory illnesses such as asthma may experience these symptoms more severely.
The best way to avoid an unpleasant experience with Red Tides is to monitor reports from health agencies and heed public warnings. You should try to reduce exposure by avoiding winds blowing onshore, reducing time outside, and certainly keeping off the beach. You should use your home air conditioner less and use high quality small particulate matter-capture air filters. If you are driving, keep the vehicle air circulating within the cabin and avoid importing outside air.
Red Tides have been recorded for centuries and are here to stay. Learn more about what you can do to help prevent Red Tides and otherwise assist ocean health by becoming involved with Coastal/Oceanographic Organizations in your area.
https://oceanservice.noaa.gov/facts/redtide.html, What is a red tide? August 6, 2018
https://www.cdc.gov/habs, Centers for Disease Control and Prevention, Harmful Algal Bloom (HAB)-Associated Illness, June 19, 2018