April 6, 2012 – New England is expected to experience a “moderate” regional “red tide” this spring and summer, report NOAA-funded scientists working in the Gulf of Maine to study the toxic algae that causes the bloom. The algae in the water pose no direct threat to human beings, however the toxins they produce can accumulate in filter-feeding organisms such as mussels and clams — which can cause paralytic shellfish poisoning (PSP) in humans who consume them.
Under a newly developed rating system, a moderate bloom could cause the closure of shellfish beds along an estimated 126–250 miles of coastline.
The 2012 outlook is based on the quantities of the algae Alexandrium fundyense in its dormant — or cyst — state detected in Gulf of Maine sediments last fall. These data are combined with computer simulations that model a complex range of meteorological and oceanographic conditions — winds, sunlight, rainfall, tides, and currents — that impact the size of the bloom.
“Our goal over the last ten years has been to develop a system to help the shellfish industry and environmental managers better plan for the annual bloom,” says Woods Hole Oceanographic Institution (WHOI) biologist Don Anderson, who has worked with WHOI colleague Dennis McGillicuddy and North Carolina State Univ. (NCSU) Prof. Ruoying He to develop the computer model to help predict the intensity and location of blooms.
Scientists are unable to make a precise forecast of where and when the regional bloom will make landfall because bloom transport depends on episodic weather events and currents that cannot be predicted months in advance. Rather, the scientists use the computer model to produce a range of bloom scenarios – or an “ensemble forecast” – tracking variables like wind direction and water characteristics based on previous years’ conditions. This is similar to the system used to forecast hurricanes.
A number of factors could impact the forecast. For instance, changing characteristics of water in the Gulf of Maine can have a direct effect on the growing conditions for Alexandrium.