red tides and dinoflagillates (algae)


Is there need to be concerned?

Florida is one of the many places around the world that feel, and observe the direct effects of red tide on the environment. Before we get started, lets get the basics on red tide.

Red Tide...What is it?

Red tide is a result of the intensive multiplication of dinoflagellates that give the water in which they inhabit a redish-brown color. Red tide, also known as dinoflagellate "blooms" , are caused by Gymnodinium breve - a small, single-celled "algae". G. breve is commonly found in warm saltwater, but if necessary, this organism can adapt to life and exist in areas of low temperature. The redish-brown color created by G. breve is a clear sign of red tide, but sometimes the organism may not even produce a visible color to alert man of what's going on in the water. Many are not aware of the fact that seasonal red tide is not a man made event, but rather it is a natural occurrence that can not be predicted. The only way to know of the occurrence of red tide is to wait until it happens. There is no machine or person that can accurately and precisely predict when the next red tide bloom will occur nor can they predict how long one will last. The phenomenon of red tide is one that has caught the interests of scientist worldwide.

picture of the redish color given to the water during red tide

The damages of red tide are extrememly visible. Thousands upon thousands of marine life die due to the toxins produced by the dinoflagellates. The photo below clearly illustrates the damages of red tide among marine life. Red tide can extend for miles along a shore line and last for weeks on end. Red tide continues to boggle the minds of scientists while threatening marine life and the fishing industry.

photo: taken on September 12, 1995 at North Lido Beach by Robert Myers

Should I be concerned about Red Tide?

YES. . .Red tide is an event that affects everyone, directly or indirectly. Every year extraordinary numbers of fish and other marine life die due to the toxins produced by G. breve. Filter feeding mollusks filter the water, containing the G. breve blooms, and therefore become highly concentrated with the dinoflagellate toxin. If eaten uncooked, or improperly cooked by an unsuspecting human, the concentrated toxin in the mollusk could easily poison the person. This is an indirect effect of red tide. The direct effects of this dinoflagellate are encountered more by those who live along the shoreline where ride tide occurs. Many people often suffer from irritation of the eyes, nose and throat. Other complications of red tide in humans can be much more severe. Unfortunately those who suffer from chronic respiratory conditions can really feel the effects of red tide. It is suggested that these people try to remain away from the dinoflagellate blooms. While the effects of red tide on humans can be rather severe, the more milder complications usually clear up about 24 hours after exposure to the blooms is discontinued.

Microscope image of red tide cells. A healthy red tide cell (top) and a "stressed" cell (bottom)