Harmful Algal Bloom Forecasts

Experimental Gulf of Maine Alexandrium fundyense Nowcast/Forecast Simulation

Results here represent model solutions initiated from a cyst abundance map from November 2016, with germination, growth, and transport of Alexandrium fundyense cells driven by the factors listed below.  This model is a demonstration, and may not  represent actual conditions in the Gulf of Maine.

2017 Archive - Modeled A. fundyense Bloom Forecast

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For full animation, please refer to this link.

Abundance for top 1-cm sediment layer collected in fall 2016 (cells/cm2)

Physical circulation model

  • ROMS-based Gulf of Maine model on NCSU/WHOI domain (~2-3 km horizontal grid spacing resolution)
  • Seven Tidal Constituents (M2, S2, N2, K2, K1, O1, Q1) from driven by ADCIRC tidal forcing in the open boundary (Luettich et al., 1992)
  • 6-hourly wind and heat fluxes from NOAA/NCEP NOMADS (~33-km resolution)
  • Daily river discharge from Unites States Geological Survey
  • Sea surface temperature from NOAA blended SST for surface heat flux correction (https://podaac.jpl.nasa.gov/SeaSurfaceTemperature)
  • Initial conditions and open boundary conditions from HYCOM

Alexandrium fundyense model

  • Population dynamics from Stock et al. (2005); McGillicuddy et al. (2005), He et al., (2008), Li et al.(2009), and Li et al. (in prep.)
  • Cyst maps from fall 2016 Survey, extrapolated based on Solow et al. (2014)
  • Daily Solar radiation used for A. fundyense model derived from NOAA NOMADS to be consistent with physical forcing;
  • Monthly climatological nutrient fields from University of Maine (Rebuck and Townsend, 2014)
  • The mortality rate of A. fundyense is now parameterized using the temperature dependent Q10 formulation (Durbin and Durbin, 1992).
  • The Alexandrium fundyense was initiated on March 1, 2017 with zero concentration.


  • Durbin, E. G., & Durbin, A. G. (1992). Effects of temperature and food abundance on grazing and shortterm weight change in the marine copepod Acartia hudsonica. Limnology and Oceanography, 37(2), 361-378.
  • He, R., McGillicuddy, D. J., Keafer, B. A., & Anderson, D. M. (2008). Historic 2005 toxic bloom of Alexandrium fundyense in the western Gulf of Maine: 2. Coupled biophysical numerical modeling. Journal of Geophysical Research: Oceans, 113(C7).
  • Li, Y., He, R., McGillicuddy, D. J., Anderson, D. M., & Keafer, B. A. (2009). Investigation of the 2006 Alexandrium fundyense bloom in the Gulf of Maine: in-situ observations and numerical modeling. Continental Shelf Research, 29(17), 2069-2082.
  • Li et al. (in prep): Diagnosing the 2008 Alexandrium fundyense bloom evolution in the Gulf of Maine.
  • Luettich, R.A., Jr., S. Hu, J.J. Westerink, and N.W. Scheffner, 1992, Modeling 3-D Circulation Using Computations for the Western North Atlantic and Gulf of Mexico, Estuarine and Coastal Modeling II, M. Spaulding [ed.], ASCE, pp.632-643.
  • McGillicuddy, D. J., Anderson, D. M., Lynch, D. R., & Townsend, D. W. (2005). Mechanisms regulating large-scale seasonal fluctuations in Alexandrium fundyense populations in the Gulf of Maine: results from a physical–biological model. Deep Sea Research Part II: Topical Studies in Oceanography, 52(19), 2698-2714.
  • Rebuck, N. D., & Townsend, D. W. (2014). A climatology and time series for dissolved nitrate in the Gulf of Maine region. Deep Sea Research Part II: Topical Studies in Oceanography, 103, 223-237.
  • Solow, A. R., Beet, A. R., Keafer, B. A., & Anderson, D. M. (2014). Testing for simple structure in a spatial time series with an application to the distribution of Alexandrium resting cysts in the Gulf of Maine. Marine Ecology Progress Series, 501, 291-296.
  • Stock, C. A., McGillicuddy, D. J., Solow, A. R., & Anderson, D. M. (2005). Evaluating hypotheses for the initiation and development of Alexandrium fundyense blooms in the western Gulf of Maine using a coupled physical–biological model. Deep Sea Research Part II: Topical Studies in Oceanography, 52(19), 2715-2744.

Disclaimer: This result is for experimental only. For questions, please email Yizhen Li or Richard Stumpf.