Domoic acid-producing diatom blooms in Monterey Bay, California: 1991-1993
Version of Record online: 30 MAY 2006
Copyright © 1994 Wiley-Liss, Inc., A Wiley Company
Volume 2, Issue 5, pages 271–279, September/October 1994
How to Cite
Walz, P. M., Garrison, D. L., Graham, W. M., Cattey, M. A., Tjeerdema, R. S. and Silver, M. W. (1994), Domoic acid-producing diatom blooms in Monterey Bay, California: 1991-1993. Nat. Toxins, 2: 271–279. doi: 10.1002/nt.2620020505
- Issue online: 30 MAY 2006
- Version of Record online: 30 MAY 2006
- Manuscript Accepted: 11 MAR 1994
- Manuscript Received: 2 OCT 1993
- Amnesic shellfish poisoning (ASP);
- Phytoplankton ecology;
During the autumn of 1991, numerous seabird fatalities in Monterey Bay, California, led to the discovery of a new domoic acid-producing diatom, Pseudonitzschia australis. Since this initial event, sizable populations of P. australis, as well as other likely toxin producers, P. pungens f. multiseries and P. pseudodelicatissima, have occurred biannually in Monterey Bay. Using the highly sensitive FMOC-HPLC method, we detected domoic acid whenever Fseudonitzschia australis was found in the plankton, even at densities as low as 4.0 × 103 cells/L. Based on correlations of domoic acid and P. australis abundances and the overwhelming biovolume dominance of P. australis, we conclude that P. australis has been the major domoic acid producer during the period of our study.
Our study suggests that P. australis cells may always be toxic in natural populations and that toxin concentrations on a per-cell basis have no statistically significant relationship to population density or to nutrient concentrations other than silicate. Cellular levels of domoic acid were positively correlated with silicate concentrations, which is at variance with reports from prior culture experiments. These conclusions must be tentative because of the limited extent of our sampling. Nevertheless, these preliminary data indicate that further investigations of environmental conditions affiliated with cell growth and toxin production in P. australis are warranted.
As a practical matter, domoic acid in the pelagic environment cannot be reliably or consistently detected by monitoring domoic acid levels in intertidal mussels. Direct measurement of domoic acid using sensitive HPLC methods is probably the most cost-effective and accurate approach for an ongoing phycotoxin monitoring program. © 1994 wiley-Liss, Inc.