Toxins from annual blooms of Alexandrium fundyense accumulate in shellfish; shellfish harvesting closures protect human health, but are economically disruptive. Seed-like cysts produced by A. fundyense accumulate in bottom sediments in the fall and hatch in the spring to start new blooms. Cyst maps are critical components of predictive models used to provide early warning of A. fundyense blooms, which are now being incorporated into the NOAA HAB Operational Forecasting System (HAB-OFS).
Why We Care
The Gulf of Maine (GoM) and its adjacent southern New England shelf is a vast region with extensive shellfish resources, large portions of which are frequently contaminated with paralytic shellfish poisoning (PSP) toxins produced by the planktonic dinoflagellate, Alexandrium fundyense (aka New England red tide). PSP is one of the most widespread and severe poisoning syndromes associated with harmful algal blooms (HABs). A. fundyense, like many dinoflagellates, has both a vegetative stage, where cells grow in surface waters, usually in the late spring and summer, and seed-like cysts that overwinter in sediments on the bottom. Environmental factors and oceanographic conditions regulate transformations between these stages and, thus, the magnitude, frequency, and location of toxin-producing blooms.
What We Are Doing
This project uses observations from an earlier Ecology and Oceanography of Harmful Algal Blooms (ECOHAB) project as well as new laboratory experiments and numerical model simulations to characterize A. fundyense resting stage (cyst or seed) distributions and dynamics in waters and sediments of the GoM. It is focusing on several aspects of that dynamic – the processes controlling the delivery, deposition, resuspension, and accumulation of resting cysts. The long-term goal of this and a related GOMTOX project is to develop models that will allow prediction and early warning of A. fundyense blooms in the GoM.
The objectives of this project are to:
- conduct statistical analysis of all the annual cyst maps in order to determine the minimum number of stations that need to be sampled for accurate future predictions;
- conduct laboratory experiments and analyze field data to understand how cysts sink to the bottom and how sediments and cysts are resuspended from the bottom and transported around the GoM; and
- incorporate this information into the existing physical-biological model for Alexandrium that predict blooms.
This project is part of the Ecology and Oceanography of Harmful Algal Blooms (ECOHAB) Program. The project is led by Dr. Donald Anderson, Woods Hole Oceanographic Institution. Partners include Dennis J. McGillicuddy and Andrew R. Solow, Woods Hole Oceanographic Institution, Cynthia H. Pilskaln, University of Massachusetts, Dartmouth, Richard P. Signell and Bradford Butman, U.S. Geological Survey.
Benefits of Our Work
The results of this project have been incorporated into the predictive model which has provide an annual outlook, similar to the annual hurricane outlook issued by NOAA National Weather Service, since 2008 (see list below). That model is being incorporated into NOAA’s planned operational forecasting system for PSP in the GoM (HAB-OFS) through a PCMHAB project. Continued refinement of our understanding of cyst formation and transport will greatly enhance the capability for HAB forecasting in the GoM.