Hydrodynamic forcing of Alexandrium population biology

Abstract

D.J. McGillicuddy, Jr.

Blooms of the toxic dinoflagellate Alexandrium fundyense are annually recurrent phenomena in the Gulf of Maine during the spring and summer months. Toxins produced by A. fundyense accumulate in the tissues of filter-feeding shellfish such as mussels and clams. Human ingestion of these contaminated shellfish can lead to Paralytic Shellfish Poisoning (PSP), a potentially fatal illness. Understanding the factors that determine the distribution and abundance of A. fundyense is therefore of considerable economic and public health interest.

Existing data and models demonstrate strong interconnections between A. fundyense populations and the Gulf of Maine coastal current system. Indeed, coupled physical-biological models of population dynamics and hydrodynamic transport are able to simulate some of the general features of the observed A. fundyense distribution. However, such models are sensitive to the choices of the input parameters (e.g., growth rate, swimming speed, germination rate, etc). Curiously, the ability of the models to match the observations occurs in a range of this parameter space that is relatively narrow with respect to the envelope of reasonable values defined by laboratory measurements. One possible explanation for this apparent inconsistency is genetic heterogeneity in the natural populations.

We hypothesize that the aggregate distribution of A. fundyense is composed of a mosaic of genetically distinct subpopulations, each with different physiological and/or behavioral responses to environmental conditions.

The goal of this project is to understand the hydrodynamic and biological controls on these populations, their toxin production, and how these factors ultimately determine fluctuations in shellfish toxicity. Our specific aims are to:

  1. Formulate a suite of population dynamics models for the various genotypes of A. fundyense. Model formulation will be guided by existing observations, as well as laboratory experiments to be conducted in Project 1 (Anderson).
  2. Incorporate the ensemble of population models into existing models of Gulf of Maine coastal hydrodynamics.
  3. Use the coupled physical-biological models to construct hindcast simulations of A. fundyense survey observations to be collected jointly with Project 1 (Anderson).
  4. Diagnose the simulations to determine the processes regulating the space/time expression of the different genotypes in terms of A. fundyense abundance.
  5. Utilize toxigenicity data for the various genotypes (provided by Project 1 (Anderson)) together with the coupled physical-biological models (Aim 3) to make predictions of shellfish toxicity along the coast. Toxicity predictions will be tested with observations from ongoing shellfish monitoring programs.

Participants

McGillicuddy

Dr. Dennis J. McGillicuddy, Jr, Principal Investigator

Woods Hole Oceanographic Institution, MS 11
Applied Ocean Physics & Engineering
Woods Hole, MA 02543
Ph: 508-289-2683
Fax: 508-457-2194
dmcgillicuddy@whoi.edu
Research Web Site

Education:
B.A. Harvard University, 1987, Engineering Sciences
M.S. Harvard University, 1989, Applied Physics
Ph.D. Harvard University, 1993, Earth and Planetary Sciences

Research Interests:
Influence of physical forcing on planktonic ecosystems and elemental
cycling; mesoscale ocean dynamics; primary production; coastal
circulation; zooplankton population dynamics; harmful algal blooms;
numerical modeling and data assimilation.


Kosnyrev

Dr. Valery Kosnyrev, Research Associate III

Woods Hole Oceanographic Institution, MS 9
Applied Ocean Physics & Engineering
Woods Hole, MA 02543
Ph: 508-289-3513
Fax: 508-457-2194
vkosnyrev@whoi.edu

Education:
M.S. Moscow Institute of Physics and Technology, 1968, Aerodynamics/Thermodynamics
Ph.D. Marine Hydrophysical Institute, Ukraine, 1976

Research Interests:
Open ocean variability, Rossby wave dynamics, numerical modeling of the general ocean circulation, remote sensing data processing and applications, coupled physical/biological modeling.


Anderson

Dr. Laurence Anderson, Research Associate III

Woods Hole Oceanographic Institution, MS 9
Applied Ocean Physics & Engineering
Woods Hole, MA 02543
Ph: 508-289-3742
Fax: 508-457-2194
landerson@whoi.edu

Education:
B.S. University of Notre Dame, 1988, Physics
M.A. Princeton University, 1990, Atmospheric and Oceanic Sciences
Ph.D. Princeton University, 1993, Atmospheric and Oceanic Sciences

Research Interests:
Nutrient cycling and coupling between different nutrient cycles; Redfield ratios; physical-biogeochemical interactions; numerical modeling; mesoscale ocean dynamics and variability.


Stasiowski

Sue Stasiowski, Sr. Admin Assistant II

Woods Hole Oceanographic Institution, MS 9
Applied Ocean Physics & Engineering
Woods Hole, MA 02543
Ph: 508-289-2318
Fax: 508-457-2194
sstasiowski@whoi.edu


Kosnyreva

Olga Kosnyreva, Research Assistant II

Woods Hole Oceanographic Institution, MS 9
Applied Ocean Physics & Engineering
Woods Hole, MA 02543
Ph: 508-289-2611
Fax: 508-457-2194
okosnyreva@whoi.edu

Research Interests:
Physical and biogeochemical data analysis; data processing and visualization; satellite data processing; web page development.

Last updated: March 26, 2013