Ecology and Oceanography of Harmful Algal Blooms (ECOHAB)

This project is a multi-institutional effort between UCLA, UCSC, SCCWRP, UCSD, and UW. The main objective is to develop an integrated modeling system validated against available observations, to investigate the natural and anthropogenic drivers of Pseudo-nitzschia (PN) Harmful Algal Blooms (HABs) in the southern California Current System (CCS). The approach builds upon the development of a similar modeling system (ROMS-BEC) used to investigate the physical circulation and biogeochemical cycles (in particular, ocean acidification and hypoxia) along the US West Coast.

Project goals:
(1) develop an end-to-end predictive capacity for the prediction of the PN-derived toxin domoic acid (DA), in the southern CCS, evaluated against observations
(2) apply and use our integrated model to investigate the relative importance of anthropogenic inputs and other potential drivers on the frequency and severity of PN HAB events in the southern CCS
(3) provide our findings to coastal zone managers to improve marine resource management and pollution control

Field Results




Model Results

Modeling and observational synthesis activities
The goals of this project component are to:

(1) Expand the ecosystem model component of ROMS-BEC to include a previously developed mechanistic representation of PN and DA cycling
(2) Use the three-dimensional (3-D) ROMS-BEC model to conduct and evaluate high- resolution “hindcast” simulations of PN and DA production throughout the southern CCS, consistent with the observational record
(3) Conduct simulations with and without anthropogenic nutrient loadings to explicitly address their role in risk of HAB development.

The modeling results are currently being evaluated and compared with field DA observations. This work will provide a baseline for evaluating the 3-D model as well as investigate patterns and drivers of correlations between in situ DA and environmental drivers.

Lab Experiment Results




Principal Investigators

  • Clarissa Anderson
  • Daniele Bianchi
  • Faycal Kessouri
  • Raphael Kudela
  • Allison Moreno
  • Marco Sandoval
  • Jayme Smith
  • Martha Sutula



  • Kessouri, F., Bianchi, D., Renault, L., McWilliams, J. C., Frenzel, H., & Deutsch, C. A. (2020). Submesoscale currents modulate the seasonal cycle of nutrients and productivity in the California Current System. Global Biogeochemical Cycles, 34, e2020GB006578. https://
  • Kessouri, F., McLaughlin, K., Sutula, M., Bianchi, D., Ho, M., McWilliams, J.C., Renault, L., Molemaker, J., Deutsch, C. and Leinweber, A., (2021). Configuration and validation of an oceanic physical and biogeochemical model to investigate coastal eutrophication in the Southern California Bight. Journal of Advances in Modeling Earth Systems, 13(12), p.e2020MS002296.
  • Kessouri, F., McWilliams, J.C., Bianchi, D., Sutula, M., Renault, L., Deutsch, C., Feely, R.A., McLaughlin, K., Ho, M., Howard, E.M. and Bednaršek, N., 2021. Coastal eutrophication drives acidification, oxygen loss, and ecosystem change in a major oceanic upwelling system. Proceedings of the National Academy of Sciences, 118(21).
  • Sutula, M., Ho, M., Sengupta, A., Kessouri, F., McLaughlin, K., McCune, K., & Bianchi, D. (2021). Dataset of terrestrial fluxes of freshwater, nutrients, carbon, and iron to the Southern California Bight, U.S.A. Data in Brief, 106802. doi:
  • Sutula, M., Ho, M., Sengupta, A., Kessouri, F., McLaughlin, K., McCune, K. and Bianchi, D., 2021. A baseline of terrestrial freshwater and nitrogen fluxes to the Southern California Bight, USA. Marine Pollution Bulletin, 170, p.112669.
  • Deutsch, C., Frenzel, H., McWilliams, J.C., Renault, L., Kessouri, F., Howard, E., Liang, J.H., Bianchi, D. and Yang, S., 2021. Biogeochemical variability in the California Current system. Progress in Oceanography, 196, p.102565.
  • Renault, L., McWilliams, J.C., Kessouri, F., Jousse, A., Frenzel, H., Chen, R. and Deutsch, C., 2021. Evaluation of high-resolution atmospheric and oceanic simulations of the California Current System. Progress in Oceanography, 195, p.102564.
  • Trainer, V.L., Kudela, R.M., Hunter, M.V., Adams, N.G. and McCabe, R.M., 2020. Climate extreme seeds a new domoic acid hotspot on the US west coast. Frontiers in Climate, 2, p.23.
  • Trainer, V.L., Moore, S.K., Hallegraeff, G., Kudela, R.M., Clement, A., Mardones, J.I. and Cochlan, W.P., 2020. Pelagic harmful algal blooms and climate change: Lessons from nature’s experiments with extremes. Harmful Algae, 91, p.101591.
  • Moreno A.R., C. Anderson, R.M. Kudela, M. Sutula, C. Edwards, D. Bianchi. Development, calibration, and evaluation of a model of Pseudo-nitzschia and Domoic Acid Production for regional ocean modeling, In Preparation for Harmful Algae.
  • Sandoval Belmar M., J. Smith, A. Moreno, C. Anderson, D. Caron, F. Kessouri, R.M. Kudela, M. Sutula, D. Bianchi. Cross regional drivers of domoic acid producing harmful algal blooms in the California Current, In Preparation for Harmful Algae.
  • Hoel, P., Ho, M., Kessouri, F., Sutula, M., McWilliams, J., Bianchi, D. Nutrients, buoyancy and biomass: exploring the relationships of biogeochemistry plume dynamics from subsurface ocean outfalls the Southern California Bight. In Preparation.
  • Hamilton, D., Anderson, C., Hense, I., & Chapra, S. (2021). Future Perspectives in Modeling Harmful Algal Bloom (HAB) Responses to Climate Change: Guidelines for HABs modeling. Guidelines for the Study of Climate Change Effects on HABs, 120pp. doi: 10.25607/OBP-1692
  • Bernstein, S., Ruiz-Cooley, R. I., Kudela, R., Anderson, C. R., Dunkin, R., & Field, J. C. (2021). Stable isotope analysis reveals differences in domoic acid accumulation and feeding strategies of key vectors in a California hotspot for outbreaks. Harmful Algae, 110, 102117. doi: 10.1016/j.hal.2021.102117
  • Kudela, R., Anderson, C., & Ruhl, H. (2021). The California Harmful Algal Bloom Monitoring and Alert Program: A Success Story for Coordinated Ocean Observing. Frontiers in Ocean Observing: Documenting Ecosystems, Understanding Environmental Changes, Forecasting Hazards, A Supplement to Oceanography, 34(4), 84-85. doi: 10.5670/oceanog.2021.supplement.02-30
  • Grigoratou, M., Montes, E., Richardson, A. J., Everett, J. D., Acevedo‐Trejos, E., Anderson, C., ... & Muller‐Karger, F. E. (2022). The marine biodiversity observation network plankton workshops: plankton ecosystem function, biodiversity, and forecasting—research requirements and applications.