By AlexSosnowskiAccuWeather.com
AccuWeather.com has examined some of the past incidents of "Red Tide," andmost recently the situation along the Maine coast during July 2009. While thedirect cause of the phenomena is specific micro-organisms or algal blooms, weoffer some insight to the weather that may affect red tides periodicallyimpacting swimming and the fishing and shellfish industry.Red tides have been documented since the era of exploration of theAmericas.
The organism causing a particular red tide in one geographic area istypically different from, say, the organism causing a red tide on another partof the globe. So too, the weather that varies from place to place may be morefavorable for one troublesome species than the next.
Weather patterns and changes in freshwater coming into the ocean can lead tofluctuations in normal ocean currents, in turn resulting in changes in salinityand local ocean water temperatures.
A key player to the blooms throughout the globe appears to be theavailability of nutrients. The greater the nutrients and the more ideal theweather conditions, the greater the chance of a red tide. The most common formof nutrients comes from silt and dust.
In the case of the red tide along a portion of the Maine coast this month,excess rain over New England has been washing extra silt into the ocean viastreams and rivers. Additionally, while the climate on land may be cooler thanaverage this summer, the rain water washing into the ocean is, in some cases,warmer than the existing ocean water.
Interestingly, we have seen a significant amount of Saharan dust blowing offAfrica westward through the tropical Atlantic in recent weeks. This dust isrich in iron. It is possible this could also provide extra nutrients forvarious other organisms in the tropical Atlantic, Caribbean, and areas as farwest as the Gulf of Mexico.
Now, throw in the downpours that have persisted along the Southeast coast ofthe U.S. during the past couple of months, or the lack thereof along the Texascoast, and the temperature may reach the critical level for other red tides tooccur. In some cases, the rain will either cool or warm the nearby ocean, bay,or Gulf water.
We have no control over the weather and seasonal red tide issues. Atpresent, there is no way to predict a red tide. However, careful management ofrunoff into streams and rivers could help minimize the impact to the shellfishindustry and keep more in your wallet, if you consume clams, oysters andmussels.
