Blooms of the marine diatom genus Pseudo-nitzschia that produce the neurotoxin domoic acid have been documented with regularity along the coast of southern California since 2003, with the occurrence of the toxin in shellfish tissue predating information on domoic acid in the particulate fraction in this region. Domoic acid concentrations in the phytoplankton inhabiting waters off southern California during 2003, 2006, 2007, 2011 and 2017 were comparable to some of the highest values that have been recorded in the literature. Blooms of Pseudo-nitzschia have exhibited strong seasonality, with toxin appearing predominantly in the spring. Year-to-year variability of particulate toxin has been considerable, and observations during 2003, 2006, 2007, 2011 and again in 2017 linked domoic acid in the diets of marine mammals and seabirds to mass mortality events among these animals. This work reviews information collected during the past 15 years documenting the phenology and magnitude of Pseudo-nitzschia abundances and domoic acid within the Southern California Bight. The general oceanographic factors leading to blooms of Pseudo-nitzschia and outbreaks of domoic acid in this region are clear, but subtle factors controlling spatial and interannual variability in bloom magnitude and toxin production remain elusive.
KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors are grateful to the large number of people who have contributed to sample and data acquisition over the 15-year duration ofthis investigation. Additionally, this research was supported in part by the NOAA National Centers for Coastal Ocean Sciences Ecology and Oceanography of Harmful Algal Blooms Program (NA11NOS4780052, NA11NOS4780053, NA11NOS4780030), the Monitoring and Event Response for Harmful Algal Blooms Program (NA05NOS4781228, NA05NOS4781221, NA05NOS4781227NA15NOS4780177, NA15NOS4780204) and the HAB Rapid Event Response Program (Publication number ECO923, MER210, and ER25), The Environmental Protection Agency (agreement number GAD# R83-1705), and grants and/or material support from the USC Sea Grant Program, the Wrigley Institute for Environmental Studies (USC), the Southern California Coastal Water Research Project, Orange County Sanitation District, the California Department of Public Health, Hyperion Water Reclamation Plant of Los Angeles, and the Southern California Coastal Ocean Observing System. [SS]