Bight ’18 study documents domoic acid across coastal ocean seafloor

The Southern California Bight 2018 Regional Monitoring Program has completed a study examining how a toxin produced by a certain ubiquitous type of marine algae can settle and stick to seafloor sediment, and then accumulate in the tissues of small, sediment-dwelling organisms exposed to the toxin.

The study, published in February as a Bight ’18 final assessment report, detected domoic acid in sediment across 54% of the Southern California Bight continental shelf. Domoic acid also was consistently found throughout the year in the organisms that live in and on sediment – known as benthic infauna – even at times of the year when domoic acid isn’t being produced, and even in places where the toxin could not be detected in the surrounding sediment.

Domoic acid is produced by Pseudo-nitzschia, the most common type of harmful algal bloom (HAB) found in Southern California’s coastal ocean. The toxin can strand and kill marine mammals, and sicken humans who consume contaminated seafood.

The Bight ’18 Harmful Algal Blooms (HABs) study marks the first regional assessment of domoic acid in Southern California coastal sediment and benthic tissue, and lays the groundwork for future research, including probing whether the toxin is being transferred from benthic infauna to fish consumed by humans.