中国赤潮研究的新进展——球形棕囊藻赤潮及其产硫的研究

Progress of Studies on Red Tide in China ——Studies on Phaeocystis giobosa red tide and its DMS (DMSP) production

中国沿海赤潮迭起,影响日益严重。国家自然科学基金重大项目开展了一系列赤潮的基础研究。对中国赤潮新记录种——球形棕囊藻进行了分类学、生活史、藻毒素、生态特征及产硫机制的研究。核糖体18S rDNA序列测定与分析结果证明,1997年冬我国粤东海域大规模赤潮的原因种是球形棕囊藻。这是中国赤潮的一个新记录种。该藻具有复杂的异形生活史,包含两种不同的生活形态:群体和游离的单细胞。长期集约化养殖引起柘林湾海域的N、P、Fe、Mn浓度较高,为赤潮的暴发提供了物质基础。球形棕囊藻细胞具有较 强的溶血毒素特性。该藻汕头株和香港株是DMSP与DMS的高产株,其细胞内DMSP的积累与释放到外界中的DMS数量受盐度、温度等环境因子的综合制约。

Phaeocystis globosa(a new recorded red tide causative algae in China) and its morphology, taxonomy, ecological nature as well DMS production were studied. 18S rDNA gene of a Phaeocystis species from South China Sea was determined. Sequence analysis indicates that the Phaeocystis species is P. globosa instead of P. pouchetii. The life cycle of P. globosa is complex and heteromorphic, exhibiting alternations between two different morphological forms: free-living cells (motile and non - motile cells) and colonies. The high level nutrients, especially P and Fe, received from long - term aquaculture, provided material base for the red tides. Meanwhile, studies show that P. globosa contained hemolysin. The hemolysin was identified as a mixture of glycolipids. Both Santou and Hong Kong strains of Phaeocystis globosa are red tide species with high DMSP production. Intracellular DMSP accumulation and release of DMS were greatly affected by temperature and salinity. DMSP/DMS productivity per algal cell increased by high salinity and low temperature.