Rôles of temperature, salinity, and light in seasonality, growth, and toxicity of ciguatera-causing Gambierdiscus toxicus Adachi et Fukuyo (Dinophyceae)

The ciguatera-causing dinoflagellate Gambierdiscus toxicus Adachi et Fukuyo reached maximum abundance in the Florida Keys when the water temperature was ≈ 30°C; populations were over half maximum when temperature lay in the interval 27–30°C. In laboratory unialgal culture experiments, temperatures >29 and 1.4 × 10 16 quanta .cm -2 · s -1 (≈ 11% of full sunlight). Under optimum combinations of the aformentioned parameters, growth rates > 0.5 division · day -14 could be sustained and led to unusually high yields in large scale cultures of up to 360 mg (dry weight) · 1 -1. Cultures grown at 27°C were more toxic than those at 21°C (3515 ± 500 cells · MU -1 vs. 16536 ± 2400 cells · MU -1, sd). Cultures were also still capable of producing toxins at inhibiting high irradiance levels.