High brevetoxin concentrations in Gymnodinium breve blooms along the northwest Florida coast during 1999

• Published in: Journal of phycology Vol. 36; no. 3; pp. 25 - 26
• Main Authors: Greene, R M, Walker, C C, Murrell, M C, Kurtz, J C, Stanley, R S, Genthner, F J
• Format: Journal Article
• Language: English
• Published: 01-06-2000
• Subjects: Gymnodinium breve; ASW, USA, Florida
• ISSN: 0022-3646
• DOI: 10.1046/j.1529-8817.2000.99059.x

Blooms of the dinoflagellate Gymnodinium breve (i.e. red tides) produce brevetoxins (PbTx) that negatively impact the Gulf of Mexico ecosystem, human health, and local economies. Characterizing and predicting bloom events and their impacts requires knowledge of G. breve abundance and PbTx concentrations in the water column. We report results from a bloom that occurred during the fall and winter of 1999 in NW Florida coastal waters. Data were collected from 16 stations on 3 sampling dates (29 Sept., 9 Nov., 1 Dec.), including basic hydrography, nutrient concentrations, G. breve abundances, and brevetoxin concentrations. G. breve cells were enumerated using flow cytometry and PbTx's were isolated from seawater using dichloromethane (DCM) partitioning. Brevetoxins were quantified by HPLC-DAD using a C-18 column and an acetonitrile-water gradient elution. Literature estimates of total PbTx concentration (PbTx's 1, 2, 3) of cultured and field-collected G. breve suggest a range in concentration from 7 to 17 pg cell super(-1). We measured total PbTx levels that greatly exceeded these values [Sept., 47-67 pg cell super(-1) (n=5); Nov., 59-126 pg cell super(-1) (n=3), Dec., 12-63 pg cell super(-1) (n=8)]. PbTx-2 was the predominant (67-75%) PbTx isomer found in these blooms. PbTx-1 and PbTx-3 were found at 11-22% and ND-28% of total PbTx, respectively.