title: Copepods induce paralytic shellfish toxin production in marine dinoflagellates.
abstract: Among the thousands of unicellular phytoplankton species described in the sea, some frequently occurring and bloom-forming marine dinoflagellates are known to produce the potent neurotoxins causing paralytic shellfish poisoning. The natural function of these toxins is not clear, although they have been hypothesized to act as a chemical defence towards grazers. Here, we show that waterborne cues from the copepod Acartia tonsa induce paralytic shellfish toxin (PST) production in the harmful algal bloom-forming dinoflagellate Alexandrium minutum. Induced A. minutum contained up to 2.5 times more toxins than controls and was more resistant to further copepod grazing. Ingestion of non-toxic alternative prey was not affected by the presence of induced A. minutum. The ability of A. minutum to sense and respond to the presence of grazers by increased PST production and increased resistance to grazing may facilitate the formation of harmful algal blooms in the sea.
authors.affiliation: Department of Marine Ecology, Göteborg University, Tjärnö Marine Biological Laboratory, SE 452 96 Strömstad, Sweden. erik.selander@tmbl.gu.se
authors.forename: Erik
authors.initials: E
authors.lastname: Selander
authors.forename: Peter
authors.initials: P
authors.lastname: Thor
authors.forename: Gunilla
authors.initials: G
authors.lastname: Toth
authors.forename: Henrik
authors.initials: H
authors.lastname: Pavia
mesh_terms: D000818:Animals; D033342:Copepoda / Q000502:physiology*; D003463:Cues; D004141:Dinoflagellida / Q000378:metabolism*; D005247:Feeding Behavior; D008387:Marine Toxins / Q000096:biosynthesis*; D011156:Population Density
chemical_list: D008387:Marine Toxins