title: Induction of domoic acid production in the toxic diatom Pseudo-nitzschia seriata by calanoid copepods.
abstract: The toxic diatom Pseudo-nitzschia seriata was exposed directly and indirectly (separated by a membrane) to copepods, Calanus hyperboreus and C. finmarchicus, to evaluate the effects of the copepods on domoic acid production and chain formation in P. seriata. The toxicity of P. seriata increased in the presence of the copepods. This response was chemically mediated without physical contact between the organisms suggesting that it was induced by potential waterborne cues from the copepods or changes in water chemistry. Domoic acid production may be related to defense against grazing in P. seriata although it was not shown in the present study. To evaluate if the induction of domoic acid production was mediated by the chemical cues from damaged P. seriata cells, live P. seriata cells were exposed to a P. seriata cell homogenate, but no effect was observed. Chain formation in P. seriata was affected only when in direct contact with the copepods. This study suggests that the presence of zooplankton may be one of the factors affecting the toxicity of Pseudo-nitzschia blooms in the field.
authors.affiliation: Natural History Museum of Denmark, University of Copenhagen, Sølvgade 83S, DK-1307 Copenhagen K, Denmark. Electronic address: atammilehto@snm.ku.dk.
authors.forename: Anna
authors.initials: A
authors.lastname: Tammilehto
authors.affiliation: National Institute of Aquatic Resources, DTU Aqua, Section for Oceanecology and Climate, Technical University of Denmark, DTU, Kavalergården 6, DK-2920 Charlottenlund, Denmark; Greenland Climate Research Centre, Greenland Institute of Natural Resources, Nuuk, Greenland. Electronic address: tgin@aqua.dtu.dk.
authors.forename: Torkel Gissel
authors.initials: TG
authors.lastname: Nielsen
authors.affiliation: Alfred Wegener Institut-Helmholtz Zentrum für Polar- und Meeresforschung, Ökologische Chemie, Am Handelshafen 12, 27570 Bremerhaven, Germany. Electronic address: Bernd.Krock@awi.de.
authors.forename: Bernd
authors.initials: B
authors.lastname: Krock
authors.affiliation: Department of Bioscience, Roskilde, Aarhus University, Frederiksborgvej 399, PO Box 358, 4000 Roskilde, Denmark. Electronic address: efm@bios.au.dk.
authors.forename: Eva Friis
authors.initials: EF
authors.lastname: Møller
authors.affiliation: Natural History Museum of Denmark, University of Copenhagen, Sølvgade 83S, DK-1307 Copenhagen K, Denmark. Electronic address: nlundholm@snm.ku.dk.
authors.forename: Nina
authors.initials: N
authors.lastname: Lundholm
mesh_terms: D000818:Animals; D033342:Copepoda / Q000502:physiology*; D017377:Diatoms / Q000502:physiology*; D017753:Ecosystem; D007608:Kainic Acid / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: C012301:domoic acid; D007608:Kainic Acid
keywords: Calanus; Diatom; Domoic acid; Grazing; Pseudo-nitzschia seriata; Toxin production