Causality of an extreme harmful algal bloom in Monterey Bay, California, during the 2014–2016 northeast Pacific warm anomaly. Issue 11 (5th June 2017)

• Record Type: Journal Article
• Authors: Ryan, J. P.; Kudela, R. M.; Birch, J. M.; Blum, M.; Bowers, H. A.; Chavez, F. P.; Doucette, G. J.; Hayashi, K.; Marin, R.; Mikulski, C. M.; Pennington, J. T.; Scholin, C. A.; Smith, G. J.; Woods, A.; Zhang, Y.
• Is Part Of: Geophysical research letters. Volume 44:Issue 11(2017)
• Page Start: 5571
• Page End: 5579
• Publication Date: 2017-06-05
• Subjects: harmful algal bloom -- Pseudo‐nitzschia -- domoic acid -- silicate limitation -- marine heat wave; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2017GL072637
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: An ecologically and economically disruptive harmful algal bloom (HAB) affected much of the northeast Pacific margin in 2015, during a prolonged oceanic warm anomaly. Caused by diatoms of the genus Pseudo‐nitzschia, this HAB produced the highest particulate concentrations of the biotoxin domoic acid (DA) ever recorded in Monterey Bay, California. Bloom inception followed strong upwelling during the spring transition, which introduced nutrients and eliminated the warm anomaly locally. Subsequently, moderate and intermittent upwelling created favorable conditions for growth and accumulation of HAB biomass, which was dominated by a highly toxigenic species, P. australis . High cellular DA concentrations were associated with available nitrogen for DA synthesis coincident with silicate exhaustion. This nutrient influence resulted from two factors: (1) disproportionate depletion of silicate in upwelling source waters during the warm anomaly, the most severe depletion observed in 24 years, and (2) silicate uptake by the dense diatom bloom. Key Points: The most toxic algal bloom ever recorded in Monterey Bay, California, occurred in spring 2015, during a hiatus in a prolonged warm anomaly The dense bloom of Pseudo‐nitzschia australis resulted from a strong spring upwelling transition followed by intermittent upwelling Toxicity was influenced by anomalously low ratios of silicate to nitrate that predisposed the bloom to silicate exhaustion