Climatic regulation of the neurotoxin domoic acid

Significance

We investigate regulation of domoic acid, a potent marine phycotoxin, at the climate scale. Due to the threat domoic acid can pose to public health, marine wildlife, and coastal economies, decades of laboratory experiments have examined controls on domoic acid production without reaching consensus on reliable toxin-producing conditions. Our findings reveal an association between domoic acid in shellfish and climate-scale warm ocean conditions, a unique, large-scale perspective relative to previous work.

Abstract

Domoic acid is a potent neurotoxin produced by certain marine microalgae that can accumulate in the foodweb, posing a health threat to human seafood consumers and wildlife in coastal regions worldwide. Evidence of climatic regulation of domoic acid in shellfish over the past 20 y in the Northern California Current regime is shown. The timing of elevated domoic acid is strongly related to warm phases of the Pacific Decadal Oscillation and the Oceanic Niño Index, an indicator of El Niño events. Ocean conditions in the northeast Pacific that are associated with warm phases of these indices, including changes in prevailing currents and advection of anomalously warm water masses onto the continental shelf, are hypothesized to contribute to increases in this toxin. We present an applied domoic acid risk assessment model for the US West Coast based on combined climatic and local variables. Evidence of regional- to basin-scale controls on domoic acid has not previously been presented. Our findings have implications in coastal zones worldwide that are affected by this toxin and are particularly relevant given the increased frequency of anomalously warm ocean conditions.