南海三亚湾及邻近海域海洋蓝藻类群组成、分布及演替特征

Species and community succession of marine cyanobacteria in Sanya Bay,South China Sea

对海南省三亚湾及邻近海域的主要生态系统的真光层水域、珊瑚礁、红树林、海藻垫生态系统中的海洋蓝藻的种类、分布和季节变化特点进行调查研究,共采集和分离了11属24种蓝藻。结果表明,三亚湾海域真光层水域主要以来自外海的外源性海洋蓝藻束毛藻为主要优势群落,其次有共生蓝藻胞内植生藻Richelia intracelluu-laris和单细胞蓝藻集胞藻属Synechocystis,其中束毛藻主要在南海季风转换期和西南季风控制期的3—8月为主,而蓝藻胞内植生藻的硅藻根管藻共生体主要出现在8—10月的另一季风转换期。在珊瑚礁生态系统中,蓝藻呈多样性分布,有集胞藻属、鱼腥藻属Anabaena、念珠藻属Nostoc、眉藻属Catothrix、颤藻属Oscillatoria和鞘丝藻属Lyngbya,它们主要在3月下旬至8月生物量较高,束毛藻也是珊瑚礁生态系中蓝藻的重要组成部分。红树林生态系统中蓝藻主要以颤藻为主要优势种,其次是鞘丝藻也占重要的比例,在4—10月底都有较高的生物量,它们主要分布在0—5cm深的表土层,其次在红树的根际、气生根和幼苗的茎叶表面都有分布。海洋近岸微型海藻垫中,有些群落主要以颤藻属和鞘丝藻属为主,有些微藻垫以眉藻属为主要优势属种,蓝藻种群随季节的变化有明显的演替。

Marine cyanobacteria are the main contributor of primary productivity in tropical oligotrophic oceans. From January 2002 to January 2005, the composition, distribution and seasonal succession of marine cyanobacteria were investigated in the Sanya Bay and the adjacent waters, and 24 species of 11 genera were collected and isolated. The results showed that planktontic Trichodesmium spp. was the predominant pelagic cyanobacterium in the Sanya Bay, and the highest biomass occurred during the SW monsoon （from March to August） ; while Richelia spp. （endosymbiotic in the diatom Rhizosolenia） and Synechocystis sp. were detected during the intermonsoon （from August to October）. In coral reef ecosystems marine cyanobacteria included Synechocystis sp. , Anabaena spp. , Nostoc sp. , Calothrix spp. , Oscillatoria sp. and Lyngbya spp., etc. Most of them were found in high abundance from March to August. Oscillatoria spp. , mainly distributing in the topsoil （0-5cm）, were dominant species in mangrove ecosystems, and they were also found in the root-sediment, pneumatophore and the surface of barks and leaves of the mangrove. Microbial mats were widely distributed on the limestone surface of rocky shores of the Sanya Bay. The dominant cyanobacterial members usually included Oscillatoria spp. , Lyngbya spp. and heterocystous Calothrix spp. Obvious seasonal succession of cyanobacterium community structure was detected in the Sanya Bay.