In November 2015, scientists from NOAA’s National Centers for Coastal Ocean Science and Woods Hole Oceanographic Institution embark on a 10-day sediment sampling mission in the Gulf of Maine. By examining sediment cores for the presence of seed-like cysts released by Alexandrium fundyense, a common type of harmful algae, researchers hope to improve forecasting of harmful algal bloom (HAB) events along the New England coast.
Alexandrium, commonly known as red tide, has both a vegetative stage when cells grow in surface waters, usually in late spring and summer, and a stage when seed-like cysts overwinter in sediments on the bottom. Forecasts of the extent and severity of Alexandrium blooms depend on a map of the alga’s cysts in Gulf of Maine sediments — which enter into the vegetative stage forming next year’s bloom — and computer models simulating a range of bloom scenarios based on previous years’ ocean conditions.
The Gulf of Maine and its adjacent southern New England shelf have extensive shellfish resources, large portions of which are frequently contaminated with toxins produced by Alexandrium. The toxins can cause paralytic shellfish poisoning in people who eat contaminated seafood. State managers use HAB forecasts to monitor Alexandrium toxins, ensuring shellfish are safe for human consumption.