This year an array of sensors are watching for harmful red tides in the Gulf of Maine.
The red tide is caused by the germination of dormant cysts of alga called Alexandrium fundyense, which produces a toxin that can cause paralytic shellfish poisoning. Another name for a red tide is “harmful algal bloom” or HAB.
Scientists have been monitoring red tides for years, so that they can warn people when problems are about to occur. They typically base their annual red tide forecast on the abundance of cysts in bottom sediments combined with a computer model that simulates a range of bloom scenarios based on previous years’ conditions. However, oceanographic conditions are changing which meant that the forecast for both 2010 and 2013 were inaccurate.
This year, then, researchers are using four robotic instruments called Environmental Sample Processors (ESPs) that measure bloom concentration and toxins at several spots along the Gulf of Maine and provide near real-time data on toxic algae which they transmit to shore. The ESPs are mounted to ocean buoys and will detect and estimate concentrations of algal species that cause red tides and one of the potentially fatal toxins they produce.
“The ESPs are not a replacement for state-run programs that monitor naturally occurring marine toxins in shellfish,” said Kohl Kanwit, Director of the Bureau of Public Health for the Maine Department of Marine Resources. “Instead, they provide valuable data on the algal cells and associated toxins in coastal waters, giving managers early warning and a more complete picture of the magnitude and distribution of HAB events.”
Photo credit: Photo by Isaac Rosenthal, Woods Hole Oceanographic Institution & Northeastern University