Adsorption of domoic acid to marine sediments and clays

Abstract

Conditional solid-water distribution coefficients (K(d)) for the adsorption of domoic acid (DA) to a series of complex sediments and clays were determined in artificial seawater. K(d) ranged from 5.11 L g(-1) to 0.97 L g(-1), with a corresponding ranking of: kaolinite > Gulf of Mexico sediment > Santa Barbara Basin sediment > Bread and Butter Creek sediment > poorly crystallized kaolin > Ca-montmorillonite > Na-montmorillonite > well crystallized kaolin > diatomaceous earth. Adsorption correlated with the anion exchange capacity of the clays tested (R(2) = 0.98), but not the more structurally complex sediments. The effect of added transition metals (Fe(iii), Cu(ii), Al(iii)) and terrestrially derived dissolved organic matter (Suwannee River DOM, SRDOM) on DA adsorption to Na-montmorillonite, well crystallized kaolin, and Gulf of Mexico sediment, was also tested. The addition of transition metals led to increased adsorption to all surfaces by a factor of 2-7, presumably by enabling the adsorption of DA-metal complexes. SRDOM enhanced DA adsorption by a factor of approximately 2.5. The release of adsorbed DA from sediments was also examined. Under our conditions, adsorbed DA equilibrated with the overlying aqueous phase within minutes with approximately 50% release.

Trophic Transfer of the Harmful Algal Toxin Domoic Acid as a Cause of Death in a Minke Whale (<I>Balaenoptera acutorostrata</I>) Stranding in Southern California

“…Four MRM transitions from protonated DA were monitored: m/z 312 → 266, m/z 312 → 248, m/z 312 → 193, and m/z 312 → 161. DA analysis of the sediment trap samples was performed using similar LC-MS methods as described in Burns & Ferry (2007).…”

Pseudo-nitzschia physiological ecology, phylogeny, toxicity, monitoring and impacts on ecosystem health

“…Some carnivores, like the swimming crab (Polybius henslowii), can contain high levels of DA but there have been no recorded incidents of poisoning in their predator, the yellow-legged gull (Larus cachinnans) that feeds on them almost exclusively (Á lvarez, 1968;Munilla, 1997;Costa et al, 2003). Vertical flux of DA to the sediment appears to be a substantial source of toxin to the benthic food chain (Sekula-Wood et al, 2009 as DA is stable when adsorbed onto sediments (Burns and Ferry, 2007), long after Pseudo-nitzschia blooms have dissipated in the upper water column. There may be a limit in the number of trophic transfers over which DA can still be present at high enough concentrations to cause a toxic event.…”

“…Impacts of DA on marine wildlife at various levels within the food web have also been observed, and this toxin is known to contribute to the deaths of seabirds, sea otters, sea lions and whales. The adsorption of DA, especially to sediments (Burns and Ferry, 2007), facilitates its potentially long-lasting impacts, particularly to the benthic food chain. Here we summarize those impacts of DA on marine wildlife as well as our increased knowledge about Pseudo-nitzschia and DA over the last decade, including changes in worldwide range and impacts, phylogeny, physiology, ecology, monitoring and public health impacts.…”

A Time Series of Water Column Distributions and Sinking Particle Flux of Pseudo-Nitzschia and Domoic Acid in the Santa Barbara Basin, California

“…For example, Sekula-Wood et al [ 30 , 32 ] found high quantities of DA in sediment traps at a depth of 540 m in the Santa Barbara Basin, (>20,000 ng/g sediment), thereby providing a source of DA to benthic and pelagic feeders. The transport of DA to sub-surface waters is likely mediated by secondary processes, such as fecal pellet production, marine snow aggregation, and adsorption onto the surfaces of particles [ 27 , 32 , 33 , 34 ] that sink rapidly, exceeding 100 m d −1 [ 30 , 32 , 35 ]. These particle transport processes help to explain the presence of DA in benthic food webs in the absence of an ongoing surface bloom [ 36 , 37 ], thereby allowing for the possibility of DA poisoning long after a toxic Pseudo-nitzschia bloom subsides [ 30 , 31 ].…”