2010—2011年东海藻华高发区水体层化对东海原甲藻(Prorocentrum donghaiense Lu)藻华的影响

IMPACT OF WATER STRATIFICTION ON PROROCENTRUM DONGHAIENSE LU BLOOMS IN HIGH-FREQUENCY HAB OCCURRENCE AREA OF THE EAST CHINA SEA IN 2010—2011

本文通过2010年和2011年不同时空角度对东海原甲藻藻华进行调查,研究水体层化对藻华发生和发展的影响。结果显示,起初东海原甲藻在50m等深线附近的外海繁殖与聚集,然后随着台湾暖流与长江冲淡水的相互作用,东海区域水体层化现象加剧,其细胞丰度越来越大,直至藻华发生并持续推进到近岸。大部分东海原甲藻细胞位于层化水体上方,而且当水体层化现象明显时,藻华的发展最为迅速且呈大规模爆发状态。结果还显示当出现叶绿素高值层时,总是伴随出现温盐突变现象。本项研究不仅第一次从时间角度记录了东海原甲藻藻华的发展动态,而且还发现了东海水体层化现象为东海原甲藻藻华的发生和发展提供了多种环境因子条件,这为该藻华的监控和预测提供了重要的科学依据。

Large-scale blooms caused by Prorocentrum donghaiense Lu frequently occurs in the East China Sea in recent years. These blooms are affected by multiple factors that closely related to water stratification. We conducted two surveys on the P. donghaiense blooms at different spatio-temporal scales in 2010 and 2011 to explore the mechanism of influence by water stratification. The surveys show that P. donghaiense cells grew and aggregated around 50m isobath offshore first, and then when water stratification formed as the result of the interaction between the Taiwan Warn Current and the Changjiang River freshwater, the cell abundance increased rapidly and finally bloomed. P. donghaiense cells amassed in the upper layer of stratified water, and bloomed quickly and widely in distinctly stratified water. In addition, when there were thin layers of high chlorophyll-a concentration, sharp changes took place in temperature and salinity. We first recorded the development of P. donghaiense blooms in temporal scale in the East China Sea, and proposed that stratified water could provide multiple environmental conditions in favor of P. donghaiense blooming, offering scientific supports to monitor P. donghaiense blooms.