Aquatic Sciences Meeting, Albuquerque 2001

CS15 Harmful Algal Blooms

Date: Tuesday, February 13, 2001, Time: 2:15:00 PM

Location: Cochiti/Taos

Lippemeier, S, , Research and Technology Center, University of Kiel, Büsum, Germany, lippem@ftz-west.uni-kiel.de

Frampton, D, , CSIRO Microalgae Research Centre, Hobart, Australia, dion.frampton @marine.csiro.au

Negri, A, P, Australian Institute of Marine Science, Townsville, Australia, a.negri@aims.gov.au

Blackburn, S, , CSIRO Microalgae Research Centre, Hobart, Australia, susan.blackburn@marine.csiro.au

STRONG EFFECTS OF VARYING PHOSPHATE SUPPLY ON GROWTH, VARIABLE FLUORESCENCE AND TOXICITY OF THE DINOFLAGELLATE ALEXANDRIUM MINUTUM

Batch cultures of A. minutum were used to study the effects of phosphate-limitation and subsequent phosphate (P) resupply on growth, production of PSP-toxins and variable chlorophyll fluorescence. Growth and photosynthetic efficiency were greatly impaired in P-limited cells and could be increased to P-replete conditions due to P-spiking. Cellular toxicity and volumetric toxin production of P-limited cultures were enhanced by a factor of 10 and 2.5 respectively compared to P-replete cultures after 13 days. Unlike to cellular toxicity, volumetric toxin production was not affected by P-spiking within 4 days. Variable chlorophyll fluorescence was applied for the first time on toxic dinoflagellates and appeared to be highly correlated to P-supply and toxin production of the cells. Our results show that P-supply has to be considered as an important factor for the toxin production during blooms of A. minutum. Furthermore variable chlorophyll fluorescence measurements might provide a useful tool to monitor the physiology and toxin production of A. minutum populations.

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Aquatic Sciences Meeting, Albuquerque 2001

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