大亚湾一次赤潮生消期间浮游植物群落变化研究

STUDIES ON PHYTOPLANKTON COMMUNITY CHANGE AT DAYA BAY DURING A RED TIDE

2003年8月12日至29日,广东省大亚湾的哑铃湾海域发生了小规模的赤潮,经现场跟踪监测发现是由锥状斯氏藻Scrippsiel latrochoidea和海洋卡盾藻Chattonella marina形成的混合赤潮。8月13日浮游植物群落由锥状斯氏藻占绝对优势,密度达6.52×106cells·L-1,占总细胞数量的99%以上;8月19日为赤潮高峰期,锥状斯氏藻密度最高时达5.59×107cells·L-1,约占总细胞数量的91%;而海洋卡盾藻在8月20日密度达到最大值1.17×107cells·L-1,约占总细胞数量的28%。以锥状斯氏藻、海洋卡盾藻占总细胞数量比例的不同,可将各站分为锥状斯氏藻控制区、海洋卡盾藻控制区及混合区3类,随环境条件的不断变化,这2种藻的数量随之变化,此3类区也处于变化之中。与海洋卡盾藻相比,锥状斯氏藻更适于在温度较高、盐度较低的情况下生长。还初步探讨了赤潮长时间持续的原因。

A small scale red tide was monitored at the Daya Bay, Guangdong Province from August 12th to 29th, 2003. The investigation results showed that the red tide was caused by Scrippsiella trochoidea and Chattonella marina. With environmental factors changing continuously, their quantities kept changing. On August 13th, the phytoplankton community was mainly composed of Scrippsiella trochoidea, whose density was 6.52×10 6cells·L -1 and its proportion in phytoplankton population was over 99%. The red tide achieved its peak on August 19th, when Scrippsiella trochoidea reached its maximum, while Chattonella marina reached its maximum on August 20th. Compared with Chattonella marina, Scrippsiella trochoidea was more adaptable to live in the environment of higher temperature and lower salinity. The composition of phytoplankton community at each station was also analyzed. According to the percentages of two algae, these stations could be classified into three types such as Scrippsiella trochoidea controlling, Chattonella marina controlling and mixture areas, and the three areas kept changing with time. The reason why this red tide could last for such a long time was discussed, i. e. enough stay time and relatively steady environment which suit algal growth and accumulation.