大亚湾红海束毛藻赤潮生消过程研究

Studies on a Trichodesmium erythraeum red tide in Daya Bay

2004年6月15～18日广东省大亚湾海域发生了一次红海束毛藻（Trichodesmium erythraeum）赤潮，面积达100km2，本文在现场监测与室内模拟实验的基础上，探讨了赤潮过程中红海束毛藻数量的时空分布特点及其与营养盐的关系。结果表明，赤潮高峰期（18日），表层红海束毛藻密度与叶绿素a浓度的平面分布趋势相同，呈现中心区〉过渡区〉边缘区的特点，且与水体营养盐含量（尤其是N、P）正相关；密度的垂直分布趋势是随水深的增加而迅速递减；表层藻细胞数量和叶绿素a浓度的最大值分别为4．71×10^7／L和51．6mg／m3。室内模拟实验结果显示，稀释对红海束毛藻的生长有促进作用，N：P比为16时对其生长的促进作用最大。本文还初步探讨了此次赤潮的来源和消亡的原因。

A Trichodesmium erythraeum red tide was in Daya Bay, Guangdong province from Jun. 15th to 18th, 2004 and its area was about 100 km2. The temporal and spatial distributing character of the quantity of Trichodesmiurn erythraeurn and its relationship with the nutrition during red tide were studied. The investigation results showed that the red tide got its peak on Jun. 18th, and in surface layer water the maximum density of Trichodesmium erythraeum was 471136/L and the maximum concentration of chlorophyll a was 51.6 mg/m3. The plane distributing trend of Trichodesmium erythraeum and chlorophyll a was the same, and the concentrations were the center area 〉 transition area 〉 edge area, and was positive correlation with the content of nutrition, especially with nitrogen and phosphorus. The vertical distributing trend was decreased rapidly with increasing depth. The cultivation experimental results showed that the dilution could promote Trichodesmium erythraeum to grow, and the promoting action was the most when the ratio of N： P was 16. This paper, the causes of happen and disappear of the red tide also were discussed.