南海大鹏湾海洋卡盾藻赤潮发生的环境背景

THE CAUSATIVE MECHANISM OF CHATONELLA MARINA BLOOM IN DAPENG BAY, THE SOUTH CHINA SEA

根据1991年2—3月，大鹏湾盐田水域的理化、水文、气象、海况的动态变化和大鹏湾底泥中发现海洋卡盾藻（Chattonellamarina）孢囊的事实，从生态学的角度分析并提出了1991年3月20—21日发生在大鹏湾盐田水域的海洋卡盾藻赤潮形成过程和机理。分析结果认为，此次赤潮应从3月7—10日的水温急升（≥20℃）而引发的孢囊一齐萌芽开始，此后在东南风引起的表层风海流作用下，营养细胞逐渐在湾西北部的盐田水域聚集，而16—19日水体中营养盐和金属元素的浓度急增，致使营养细胞得以大量增殖，终于引发此次赤潮．3月19日后的风速显著减弱和日潮严重不等现象对此次赤潮形成也起着重要的作用。

According to the dynamic variations of hydrology, weather and sea-condi-hon in Yanhan Waters of Dapeng Bay between February and March in 1991, and theexistence of Chalonella marina cyst found in the bottom sediments of Dapeng Bay in1992, here the authors hypothesise the formatting process and mechanisms of C.marinabloom occurred in Yanhan Waters of Dapeng Bay from March 20th to 21st 1991. Thebloom was suggested to be inihated by a large-scale germination of the dormant cellsdue to the water temperature increasing up to about 20℃ from March 7th, which isophmum for gerhanation of dormant cells of Chatonella. And then the vegetation cellsof C.marina continuously multiplied in abundance due to a long-term maintenance ofthe optimum water temperature (20-22℃) for both germination of dormant cells andgrowth of vegetative cells of C. marina from about 11th to the bloom, and a fullynitrogen suppy of organic and inorganic due to the thorough mixing of water columnby a strong southeast wind in this season. At the same time, the vegetative cells werealso driven by the strong southeast wind to accumulate continuously in the northwestpart of Dapeng Bay (Yantian Waters). After March 17th, however, the Southeast windsuddenly became much weak, and tidal current became lowly due to severe diurnalinequality. These factors made not only the vegetative cells to increase much more,but also the converged populahon not to be broken up easily. So, the bloom of Cmarina occurred at last in 20th characterised by a mean wind velocity<0.5m/s.