Red Tide Information

Several prominent reports were issued this month as related to "red tide". As we know, red tide is a phenomena that is prevalent in our costal waters.

Red tide is an algal bloom that occurs in part when there is too much nitrogen in the waters. The red tide bloom will damage sinuses and pose other health threats - especially if contaminated shellfish is consumed. Approximately 60,000 Americans are poisoned every year as a direct and indirect result of the algal blooms. The poison from the red tide bloom becomes airborne thereby irritating our sinuses, throats, eyes and lungs.

The following are some quotes from the EPA, FDA, and from a leading university research center on this subject.

Nutrients such as nitrogen and phosphorus are necessary for growth of plants and animals and support a healthy aquatic ecosystem. In excess, however, nutrients can contribute to fish disease, red or brown tide, algae blooms, and low dissolved oxygen. The condition where dissolved oxygen is less than 2 parts per million is referred to as hypoxia. Many species are likely to die below that level- the level of healthy waters is 5 or 6 parts per million. Sources of nutrients include point and non-point sources such as sewage treatment plant discharges, stormwater runoff from lawns and agricultural lands, faulty or leaking septic systems, sediment in runoff, animal wastes, atmospheric deposition originating from power plants or vehicles, and groundwater discharges.

Excessive nutrients stimulate the growth of algae. As the algae die, they decay and rob the water of oxygen. The algae also prevent sunlight from penetrating the water. Fish and shellfish are deprived of oxygen, and underwater seagrasses are deprived of light and are lost. Animals that depend on seagrasses for food or shelter leave the area or die. In addition, the excessive algae growth may result in brown and red tides which have been linked to fish kills, manatee deaths and negative impacts to scallops. Increased algae may also cause foul smells and decreased aesthetic value.

There are three types of shellfish poisonings which are specifically addressed in the NSSP Model Ordinance: paralytic shellfish poisoning (PSP), neurotoxic shellfish poisoning (NSP) and amnesic shellfish poisoning (ASP), also known as domoic acid poisoning. PSP is caused by dinoflagellates of the genus Alexandrium (formerly Gonyaulax). NSP is caused by brevetoxins produced by the dinoflagellates of the genus Karenia (formerly Gymnodinium). Both of these dinoflagellates can produce "red tides", i.e. discolorations of seawater caused by blooms of the algae. Toxic blooms of these dinoflagellates can occur unexpectedly or follow predictable patterns.

Researchers at University of North Carolina Wilmington announce the continuation of funding to study the effects of inhaled Florida red tide brevetoxins and ultimately yield treatments. The National Institute of Environmental Health Sciences awarded UNCW the five-year $7.53 million competitive renewal to further delve into the acute and chronic effects of inhaling toxic particles generated by red tides on Florida's west coast.

Daniel Baden, William R. Kenan Distinguished Professor of Marine Sciences at UNCW and program director for the study, said, "With an understanding of the molecular mechanisms of toxin action, we can recommend appropriate therapeutics for intervention and provide some measure of effects in humans. While it is not presently within our power to prevent red tides, it is certainly possible and advisable to reduce, treat and ultimately prevent inhalation exposure to these noxious agents."

By measuring red tide cells in the water, the toxin they contain, the airborne toxin in sea spray, the toxin transported ashore by wind and the amount people inhale, the team is rapidly increasing understanding about one of the most far-reaching human exposures to a natural toxin.

Florida red tide toxins affect the pulmonary, nervous, immune and genetic systems in animal models and may similarly affect humans.

sources: www.epa.gov www.fda.gov www.uncw.edu Popular Science