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Comparative study of selenium requirements of three phytoplankton species: Gymnodinium catenatum, Alexandrium minutum (Dinophyta) andChaetoceros cf. tenuissimus (Bacillariophyta)
journal contribution
posted on 2023-05-16, 11:54 authored by Doblin, M, Blackburn, SI, Gustaaf HallegraeffGustaaf HallegraeffThis study investigated the selenium (Se) requirements of three phytoplankton species which commonly bloom in southern Australian estuaries. The present study showed that the toxic dinoflagellate Gymnodinium catenatum Graham had an obligate requirement for Se (IV) in culture. After two transfers (~4 weeks ≃ 7 generations) in Se-deficient seawater medium, this phytoplankton species exhibited a decline in growth rate (25%) and biomass yield (90%), while complete cessation of cell division occurred under prolonged (8 weeks ≃ 12 generations) Se starvation. Addition of 10 -9 -10 -7 M H 2 SeO 3 to nutrient-enriched seawater medium resulted in increased G.catenatum growth and biomass yields in direct proportion to the Se concentrations offered. In contrast to G.catenatum, Se limitation was observed in the dinoflagellate Alexandrium minutum Halim after four transfers (5 weeks ≃ 20 generations) in Se-deficient medium. Exponential growth rates of A.minutum decreased slightly (5-10%) when Se was not supplied, but biomass yields decreased as much as 80-90%. The diatom Chaetoceros cf. tenuissimus Meunier showed no evidence of Se limitation even after eight transfers (8 weeks; > 60 generations) in Se-deficient medium. Variations in growth rates and biomass yields between transfers provide valuable information about the relative potential for Se limitation in the three species studied. In addition, differences in Se requirement between these bloom-forming phytoplankton species suggest that this micronutrient may play a role in structuring phytoplankton communities in southern Australian waters.
History
Publication title
Journal of Plankton ResearchVolume
21Issue
6Pagination
1153-1169ISSN
0142-7873Department/School
School of Natural SciencesPublisher
Oxford University PressPlace of publication
UKRepository Status
- Restricted