Despite nearly annual blooms of the neurotoxic dinoflagellate Karenia brevis (Davis) G. Hansen and Moestrup in the Gulf of Mexico, defining the suite of biological traits that explain its proliferation has remained challenging. Studies have described K. brevis as a low-light-adapted species, incapable of sustaining growth under high light, which is at odds with observed surface aggregations sometimes within centimeters of the sea surface and also with short-term experiments showing photosynthetic machinery accommodating high irradiances. Here, growth and photophysiology of three K. brevis isolates were evaluated under a range of environmentally relevant irradiances (10–1500 μmol photons m⁻² s⁻¹) in the laboratory. No differences in growth–irradiance curves were observed among isolates; all sustained maximum growth rates at the highest irradiances examined, even in exposures as long as three weeks. The growth efficiency α of K. brevis under light-limiting conditions appeared mediocre among dinoflagellates, and poorer than that of other phytoplankton (e.g., diatoms, cyanobacteria), implying that K. brevis is not a low-light specialist. This finding substantially alters earlier parameterizations of K. brevis growth–irradiance curves. Therefore, a model was developed to contextualize how these new growth–irradiance curves might affect bottom growth rates. This model was subsequently applied to a case study comparing seasonal light forcing offshore of Pinellas County, FL, USA, with a single empirical value for light attenuation, and seasonal bottom water temperatures. Predictions suggested that light may limit bottom growth as close as 1 km from shore in winter, but would only begin limiting growth 20 km from shore in summer. Population maintenance (no net growth) was possible as far offshore as 90 km in summer and 68 km in winter. These ranges intercept areas thought to be important for bloom initiation.

尽管神经毒性的双鞭毛藻（Brena brevis）（Davis）G. Hansen和Moestrup几乎每年都在墨西哥湾开花，但解释其增殖的一系列生物学特性仍然具有挑战性。研究表明，短毛K.brevis是低照度物种，无法在强光下维持生长，这与有时在海面几厘米范围内观察到的表面聚集体不一致，而且与短期实验表明光合作用机制能够适应高水平的光合作用。辐照度。这里，生长和三个photophysiology K.短分离下的范围内环境有关的辐照度的（10-1500微摩尔光子米进行评价^-2 小号^-1）在实验室中。分离株之间没有观察到生长-辐照度曲线的差异。在最高辐照度下，即使在长达三周的辐照下，所有材料都保持了最大的增长率。在光限制条件下，短鞭毛衣藻的生长效率α在鞭毛鞭毛虫中表现中等，并且比其他浮游植物（例如，硅藻，蓝细菌）的生长效率低，这表明短鞭毛衣藻不是弱光专家。这一发现大大改变了K. brevis的早期参数设置。生长-辐照度曲线。因此，开发了一个模型来关联这些新的增长-辐照度曲线可能如何影响最低增长率。该模型随后被应用于一个案例研究，该案例将美国佛罗里达州皮尼拉斯县近海的季节性光照强迫与光衰减和季节性底水温度的单一经验值进行了比较。预测表明，冬季光线可能会限制底部生长，距离海岸仅1 km，而夏季只会开始限制底部20 km的生长。在夏天，海上距离可能达到90公里，冬季则达到68公里，这样就可以进行人口维持（无净增长）。这些范围截取了被认为对起霜起重要作用的区域。