Aquatic Sciences Meeting, Albuquerque 2001

CS15 Harmful Algal Blooms

Date: Tuesday, February 13, 2001, Time: 12:00:00 PM

Location: Cochiti/Taos

Teegarden, G, J, Bowdoin College 6500 College Station, Brunswick, ME, USA, gteegard@bowdoin.edu

Cembella, A, D, Institute for Marine Biosciences, 1411 Oxford St., Halifax, N.S., Canada, Allan.Cembella@nrc.ca

Durbin, E, G, Graduate School of Oceanography, University of Rhode Island, Narragansett, RI, USA, edurbin@gso.uri.edu

PSP TOXIN RETENTION BY ZOOPLANKTON FEEDING ON ALEXANDRIUM FUNDYENSE – VECTOR OR SINK?

Experiments were performed to determine toxin budgets for copepods feeding on toxic Alexandrium fundyense, offered as monocultures or in mixtures of algal prey, by comparing calculated toxin ingestion rates and toxin content of copepod body tissue and fecal pellets. Both copepod tissue and fecal pellet fractions accounted for <5% each of the calculated ingested toxin, and thus >90% was lost as dissolved fraction toxin. The presence of alternate food did not significantly alter the efficiency of toxin retention. Experiments using varying concentrations of A. fundyense and alternate non-toxic species show no effect of cell concentration on toxin retention efficiency. Selective feeding was evident at high, but not low, concentrations of A. fundyense, suggesting that PSP toxins deter grazers more effectively at higher Alexandrium spp. cell concentrations. Sloppy feeding is the probable mechanism for release of dissolved toxin. Owing to low toxin retention efficiency, copepods are probably a net sink for PSP toxins produced by Alexandrium spp. Nevertheless, zooplankton can attain toxin body burdens sufficient to contribute to propagation of PSP toxins to other trophic levels.

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Aquatic Sciences Meeting, Albuquerque 2001

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