Scientists Prepare for Annual Mission to Sample Harmful Algal Bloom Cysts in the Gulf of Maine

Sampling sediment cores for seed-like cysts provide intel about future "red tide" events along the New England coast.

NOAA scientists guide the sediment corer back onto the deck so they can retrieve the sample.

Crewmembers on the NOAA ship Okeanos Explorer guide a sediment corer back onto deck so they can retrieve core samples. These sediment samples from the ocean floor are examined for the presence of seed-like cysts released by harmful alga in the region.

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.