2014年春季东海大面积甲藻赤潮的生态特征

为准确掌握东海近岸海域赤潮发生情况,深入了解东海海域赤潮发生时和未发生时的生态环境条件,根据浙江省舟山海洋生态环境监测站对东海近岸海域常年的监测结果,选定从杭州湾外侧向南到温州南麂列岛的东海近岸海域为赤潮高发区,开展生态环境研究.2014 年4 月和5 月利用专业海洋调查船,按《海洋监测规范》对东海赤潮高发海域进行了二次综合海洋生态环境调查,结果发现调查海域氮、磷营养盐含量普遍较高,4 月研究海域无机氮均值为0.406 mg·L^-1,活性磷酸盐均值0.013 mg·L^-1;5 月无机氮均值0.244 mg·L^-1,活性磷酸盐均值0.004 mg·L^-1.大多数样品无机氮超一类海水水质标准,尤其是4 月91.7%的样品超-类海水标准,5 月也有35.7%样品超-类海水标准.硝酸盐氮是无机氮的主要存在形式.2014 年5 月调查期间发生了大面积的赤潮,赤潮原因种是东海原甲藻（Prorocentrum donghaiense）,细胞密度平均在107/L 以上.分析赤潮发生前后的水环境变化,5 月调查海域海水温度有较大上升,各海域水温均超过了20 ℃,海域平均温度从4 月的15.9 ℃上升到5 月的21.9 ℃.通过本次研究发现在营养盐浓度普遍较高的调查海域,水温上升是引发赤潮的关键因素.使用专业统计软件SPSS17 发现赤潮藻类的细胞密度与水温、化学需氧量和溶解氧存在着极显著的正相关（P〈0.01）,与活性磷酸盐、硝酸盐氮和无机氮存在着显著负相关（P〈0.05）.另外本次调查还发现,大面积东海原甲藻赤潮暴发后,活性磷酸盐被大量消耗.综合目前有关东海原甲藻赤潮期间对活性磷酸盐的吸收动力学研究,发现今后应进一步加强这方面的调查研究.

Ecological Studies During Occurrence of Dinoflagellate Blooms in East China Sea Spring 2014

Ecological environmental studies were implemented in the high frequency area of red tide in East China Sea （ECS） toobtain a better understanding of red tide occurrence and ecological environmental conditions when red tide occurred or not. This areaextended from southern Hangzhou Bay to Nanji Islands of Wenzhou in the ECS, which was established according to the annualmonitoring results in the coastal areas of ECS by Zhejiang Provincial Zhoushan Marine Ecological Environmental MonitoringStation. According to “The specification for marine monitoring”, two comprehensive marine ecological environmental investigationswere conducted with marine survey vessel in April and May 2014, respectively. The results showed that nutrient concentrations of Nand P were generally high in this area, with concentrations of 0.406 mg·L^-1 and 0.013 mg·L^-1 in April, and 0.244 mg·L^-1 and 0.004mg·L^-1 in May for DIN and PO4^3--P, respectively. DIN concentrations in most areas exceeded the permitted limit of Chinese seawaterquality grade I, with 91.7% of the samples in April and 35.7% in May, respectively. And NO3^--N was the dominant existing form ofDIN in this area. Large-scale harmful algal bloom （HAB） broke out in May and the causative algae was Prorocentrum donghaiense,with mean cell density over 107/L. Analyses of environmental factors variations before and after HABs unveiled a relatively intenserising seawater temperature from 15.9 °C in April to 21.9 °C in May, with all the stations exceeded 20 °C in May in this area. Thepresent study revealed that seawater temperature was one of the critical factors for HABs in the areas with generally high nutrientconcentrations. SPSS 17.0 was used for analyzing the relationship between the concentrations of nutrients and the cell density of P.donghaiense. It was shown that the cell density was significantly and positively associated with seawater temperature, COD and DO（P〈0.01）, and negatively related to PO4^3--P, NO3^--N and DIN （P〈0.05）. Meanwhile, our study rev