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ECOHAB-GOM: The Ecology and
Oceanography of Toxic Alexandrium
Blooms in the Gulf of Maine

NOTE:   The subproject described here is one of several components of ECOHAB-GOM: The Ecology and Oceanography of Toxic Alexandrium Blooms in the Gulf of Maine, a multi-PI, multi-institutional, interdisciplinary study of the dynamics of the toxic "red tide" dinoflagellate Alexandrium sp. in the Gulf of Maine. 

The Principal Investigators are: Donald M. Anderson, Woods Hole Oceanographic Institution; David W. Townsend, University of Maine; James H. Churchill, Woods Hole Oceanographic Institution; John J. Cullen, Dalhousie University; Gregory J. Doucette, Medical University of South Carolina; W. Rockwell Geyer, Woods Hole Oceanographic Institution; John Hurst, Maine Department of Marine Resources; Maureen D. Keller,   Bigelow Laboratory for Ocean Sciences; Theodore C. Loder III, University of New Hampshire; Daniel R. Lynch, Dartmouth College; Jennifer L. Martin, Canadian Department of Fisheries and Oceans; Dennis J. McGillicuddy; Woods Hole Oceanographic Institution; Neal R. Pettigrew; University of Maine; Richard P. Signell, U.S. Geological Survey; Andrew C. Thomas, University of Maine; Jefferson T. Turner, University of Massachusetts Dartmouth. 

ECOHAB-GOM is funded jointly by NOAA and the National Science Foundation.

Click here for the main web site for the project.

University of Maine component of ECOHAB-GOM:

U.Maine Principal Investigators: David W. Townsend, Neal R. Pettigrew and Andrew C. Thomas; 5741 Libby Hall, Graduate Oceanography Program, School of Marine Sciences, University of Maine, Orono, Maine 04469

Summary and Objectives: The overall objective of ECOHAB-GOM is to understand the dynamics of the toxic "red tide" dinoflagellate Alexandrium (the planktonic organism responsible for Paralytic Shelfish Poisoning) in the Gulf of Maine by studying the physical, biological, chemical, and behavioral mechanisms underlying population abundance and distribution in several key habitats or regimes and by characterizing the transport pathways that link them.  Details can be found at the main web site (www.whoi.edu/ecohab/).

The specific objectives of the University of Maine component are to:

  • Investigate the physical oceanography, nutrient chemistry, and abundances and distributions of Alexandrium in the coastal and offshore waters of the northern Gulf of Maine and to identify the factors that regulate Alexandrium population dynamics.

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Photomicrograph (200X; darkfield) of Alexandrium, with Scripsiella sp., and Ceratium spp.  Note formation of pellicle cysts.

  • Determine the linkages between the major Gulf-wide current systems, in particular the Eastern Maine Coastal Current (EMCC) and western Maine coastal waters, and between the Gulf of Maine and the Bay of Fundy with respect to freshwater, nutrients, and Alexandrium cells.
  • Identify environmental factors that result in the initiation of Alexandrium blooms in Gulf of Maine waters, and how those blooms are controlled with respect to their spatial and temporal distributions.

Summary of Our Approach: Our component is part of the larger multi-institutional, multi-investigator study of Alexandrium dynamics in the Gulf of Maine.  Within the context of that larger study we proposed a multi-disciplinary, multi-year field and modeling program to investigate the ecology and oceanography of toxic Alexandrium blooms in the overall Gulf of Maine, including the Bay of Fundy.  Our sampling cruises and mooring deployments were planned for Years 2 (1998) and 4 (2000).  Year 3 (April 1999 to March 2000) has been reserved for data analysis and for design of Year 5 field-sampling plans.  In contrast to coastal and nearshore sites in the western Gulf of Maine, which is the region focused on by our colleagues, little was known about Alexandrium bloom dynamics in the larger domain Gulf of Maine - Bay of Fundy region (see expanded section on Research Results).  The University of Maine team has focused its attention on the oceanographic processes responsible for PSP events along the shoreline, based on the assumption that populations of Alexandrium are naturally abundant in offshore Gulf of Maine waters.  We also have investigated possible linkages between the Gulf proper and the Bay of Fundy, and between coastal and offshore waters of the Gulf, as each might provide a source of Alexandrium cells to shellfish resources in inshore waters.  In connecting our field component with that of our colleagues, we also are investigating connections with the Western Maine Coastal Current as a downstream vector and sink for cells produced offhsore and to the east. To supplement these mesoscale efforts, smaller-scale "process" studies are planned in Year 5 (July 2001), with a final synthesis component to follow immediately for all project elements.

Summary Results to date:  Results of our three survey cruises, conducted in June, July and August 1998 (aboard the R/V Cape Hatteras in June and July, and R/V Oceanus in August) are published (Townsend et al. 2001. Continental Shelf Research 48: 159-178; reprint available as PDF file). Data from the 2000 cruises aboard the R/V Cape Hatteras (April-May and June) are also available online.