National Oceanographic and Atmospheric Administration, National Ocean Service, Centers for Coastal Ocean Science, Stressor Detection and Impacts Division, Beaufort Laboratory, Beaufort, NC 28516, USA.
National Oceanographic and Atmospheric Administration, National Ocean Service, Centers for Coastal Ocean Science, Stressor Detection and Impacts Division, Beaufort Laboratory, Beaufort, NC 28516, USA.
Harmful Algae. 2018 Jul;77:81-92. doi: 10.1016/j.hal.2018.06.008. Epub 2018 Jun 28.
Despite the long history of paralytic shellfish poisoning (PSP) events in Alaska, little is known about the seasonal distribution and abundance of the causative organism, Alexandrium, or the environmental factors that govern toxic bloom development. To address this issue, a five year study (2012-2017) was undertaken in Kachemak Bay and lower Cook Inlet Alaska to determine how the occurrence of Alexandrium catenella, the dominant PSP-causing Alexandrium species, was influenced by temperature, salinity, nutrient concentrations, and other environmental factors. Cell concentrations from 572 surface water samples were estimated using quantitative PCR. Monthly sampling revealed a seasonal pattern of A. catenella bloom development that was positively correlated with water temperature. Prevailing salinity conditions did not significantly affect abundance, nor was nutrient limitation a direct factor. Elevated cell concentrations were detected in 35 samples from Kachemak Bay (100-3050 cell eq. L) while a maximum abundance of 67 cell eq. L was detected in samples from lower Cook Inlet sites. Monitoring data showed average water temperatures in Kachemak Bay increased by ∼2 °C over the course of the study and were accompanied by an increase in Alexandrium abundance. Based on these findings, 7-8 °C appears to represent a temperature threshold for significant bloom development in Kachemak Bay, with the greatest risk of shellfish toxicity occurring when temperatures exceed 10-12 °C. The role of temperature is further supported by time series data from the Alaska Coastal Current (station GAK1), which showed that summertime shellfish toxicity events in Kachemak Bay generally followed periods of anomalously high winter water temperatures. These data indicate monitoring changes in water temperatures may be used as an early warning signal for subsequent development of shellfish toxicity in Kachemak Bay.
尽管麻痹性贝类毒素 (PSP) 事件在阿拉斯加已经存在了很长时间，但人们对其致病生物亚历山大藻的季节性分布和丰度，以及控制有毒藻华发展的环境因素知之甚少。为了解决这个问题，在阿拉斯加的卡彻马克湾和下库克湾进行了一项为期五年的研究（2012-2017 年），以确定亚历山大藻属中占优势的引起 PSP 的物种亚历山大藻 catenella 的发生是如何受到温度、盐度、营养浓度和其他环境因素的影响。使用定量 PCR 估计了 572 个地表水样本中的细胞浓度。每月采样揭示了亚历山大藻 catenella 藻华发展的季节性模式，与水温呈正相关。流行的盐度条件对丰度没有显著影响，营养限制也不是直接因素。在卡彻马克湾的 35 个样本中检测到了高浓度的细胞（100-3050 个细胞当量/L），而在下库克湾站点的样本中检测到的最高丰度为 67 个细胞当量/L。监测数据显示，卡彻马克湾的平均水温在研究过程中升高了约 2°C，同时亚历山大藻的丰度也有所增加。基于这些发现，7-8°C 似乎代表了卡彻马克湾显著藻华发展的温度阈值，当水温超过 10-12°C 时，贝类毒性的风险最大。温度的作用还得到了阿拉斯加沿海流（GAK1 站）时间序列数据的支持，这些数据表明，卡彻马克湾夏季贝类毒性事件通常紧随冬季水温异常高的时期。这些数据表明，监测水温变化可能被用作卡彻马克湾贝类毒性后续发展的早期预警信号。
