A HISTORICAL RECORD OF VERTICAL DOMOIC ACID FLUXES FROM SANTA
BARBARA BASIN (CA)
Emily Sekula-Wood1, Claudia Benitez-Nelson1, Clarissa Anderson2, Astrid Schnetzer3, Nathalie
Guillocheau4, Steve Morton5, David Siegel4, and Robert Thunell1
1
University of South Carolina, Columbia, SC
University of California, Santa Cruz, CA
3
University of Southern California, Los Angeles, CA
4
University of California, Santa Barbara, CA
5
NOAA/NOS Marine Biotoxin Program, Charleston, SC
2
Recent evidence suggests that vertically sinking particles may be a substantial source of domoic
acid to bottom sediments, where it can enter the food chain of both nearshore and benthic biota
(e.g. flatfish and crabs). Sediment trap measurements in the Santa Barbara and San Pedro Basins
have found that DA-enriched sinking particles, comprised of phytoplankton aggregates and fecal
pellets, rapidly sink (within 3-5 days) to depths of 800 m following toxic Pseudo-nitzschia
surface blooms (Sekula-Wood et al. 2009). This strong surface to depth correlation further
suggests that sediment traps may provide a historical record of surface water domoic acid events
in the absence of surface water monitoring. Here, we present domoic acid measurements (n =
182) from bimonthly sediment trap samples (particulates and supernatants) collected from 540 m
in the Santa Barbara Basin from late 1993 through May 2007. Archived sediment trap samples
reveal periodic toxin events occurring in the Santa Barbara Basin as early as 1994 including four
large-scale events from 2001 to 2007. In many, but not all, instances, sediment trap toxin events
from the center of the Basin coincide with nearshore domoic acid events identified by shellfish
monitoring.
Sekula-Wood et al. Rapid downward transport of the neurotoxin domoic acid in coastal waters.
Nature Geoscience 2 (4), 272-275 (2009).