Department of Oceanography, Texas A&M University, College Station, TX 77843, USA.
Virginia Institute of Marine Science, College of William & Mary, Gloucester Point, Virginia, 23062, USA.
Harmful Algae. 2020 Sep;98:101896. doi: 10.1016/j.hal.2020.101896. Epub 2020 Aug 29.
Mixotrophic Dinophysis species threaten human health and coastal economies through the production of toxins which cause diarrhetic shellfish poisoning (DSP) in humans. Novel blooms of Dinophysis acuminata and Dinophysis ovum have occurred in North American waters in recent decades, resulting in the closure of shellfish harvesting. Understanding the ecology of Dinophysis species and their prey is essential to predicting and mitigating the impact of blooms of these dinoflagellates. The growth response of two new isolates of Dinophysis species, one isolate of Mesodinium rubrum, and two strains of Teleaulax amphioxeia were evaluated at a range of temperature, salinity, and irradiance treatments to identify possible environmental drivers of Dinophysis blooms in the Gulf of Mexico. Results showed optimal growth of T. amphioxeia and M. rubrum at 24 °C, salinity 30 - 34, and irradiances between 300 and 400 µmol quanta m s . Optimal Dinophysis growth was observed at salinity 22 and temperatures between 18 and 24 °C. Mesodinium and both Dinophysis responded differently to experimental treatments, which may be due to the suitability of prey and different handling of kleptochloroplasts. Dinophysis bloom onset may be initiated by warming surface waters between winter and spring in the Gulf of Mexico. Toxin profiles for these two North American isolates were distinct; Dinophysis acuminata produced okadaic acid, dinophysistoxin-1, and pectenotoxin-2 while D. ovum produced only okadaic acid. Toxin per cell for D. ovum was two orders of magnitude greater than D. acuminata. Phylogenies based on the cox1 and cob genes did not distinguish these two Dinophysis species within the D. acuminata complex.
混合营养型腰鞭毛虫通过产生腹泻性贝类毒素（DSP）而威胁人类健康和沿海经济，DSP 会导致人类腹泻。近年来，北美水域中出现了新的角毛藻属和卵圆菱形藻属的新型赤潮，导致贝类捕捞关闭。了解腰鞭毛虫属及其猎物的生态对于预测和减轻这些腰鞭毛藻类的赤潮影响至关重要。本研究评估了两种新的腰鞭毛虫属分离株、一种中肋骨条藻分离株和两种塔玛亚历山大藻株在一系列温度、盐度和光照处理下的生长反应，以确定墨西哥湾中腰鞭毛虫属赤潮的可能环境驱动因素。结果表明，塔玛亚历山大藻和中肋骨条藻的最佳生长温度为 24°C，盐度为 30-34，光照强度在 300 到 400 µmol 量子 m-2 s-1 之间。最优的腰鞭毛虫生长在盐度为 22 和温度在 18 到 24°C 之间。中肋骨条藻和两种腰鞭毛虫属对实验处理的反应不同，这可能是由于猎物的适宜性和不同的偷食叶绿体处理方式。墨西哥湾冬季和春季之间的表层水温升高可能会引发腰鞭毛虫赤潮的发生。这两个北美的分离株的毒素图谱不同；角毛藻属产生 okadaic 酸、dinophysistoxin-1 和 pectenotoxin-2，而卵圆菱形藻属只产生 okadaic 酸。卵圆菱形藻属的细胞毒素含量比角毛藻属高出两个数量级。基于 cox1 和 cob 基因的系统发育分析未能区分 D. acuminata 复合体内的这两个腰鞭毛虫属。
