造礁石珊瑚与其内共生的虫黄藻（共生藻）特殊的共生关系调控"珊瑚－虫黄藻"共生体的营养、生长，防御及环境适应力。共生藻（Symbiodinium）具有独特的种类多样性、群落结构及适应机制，故开展共生藻的多样性及适应性研究对于理解珊瑚礁生态系应对全球环境变化的响应有着非常重要的意义。海南珊瑚礁资源丰富，但目前也面临环境变化带来的退化和死亡。本研究拟通过三种分子学分析方法（PCR-RFLP、ITS序列的一代测序和ITS2序列的高通量测序）对海南周边海域共生藻的多样性、系统发生学进行研究，解析不同地理环境内共生藻多样性变化、分布及与珊瑚的协同进化关系。再结合传统微生物分离法，定向分离海南周边海域优势的共生藻亚系群，离体条件下研究各系群生理特性及不同逆境因子下的适应性，有助于更深层地理解“珊瑚－虫黄藻”共生体对环境协迫的响应及稳态维持机制，藻株可用于构建珊瑚礁生态系种质资源库。

The special symbiosis between scleractinian corals and intracellular, photosynthetic dinoflagellates of the genus Symbiodinium usually regulates the nutrition, development and adaptation to environment changes of symbionts. Investigating the diversity and special community structure and the adaptability of Symbiodinium is important in understanding how coral reefs will respond to envioronmental changes. The composition of the genus Symbiodinium in the coastal waters surrounding Hainan island will be investigated by PCR-RFLP of large subunit rRNA, Sanger sequencing (including direct/clone sequencing) of amplified fragments of ITS gene and next-generation sequencing (NGS) of the ITS2 gene. Moreover the relationship between the geogaraphic distribution of Symbiodinium diversity and the co-evolution of coral-algae symbionts will be analyzed. According the investigative analyses, the dominant clades and subclades of Symbiodinium will be directedly screened by the traditional method of isolation . In vitro conditions, the physiological characters of isolated different Symbiodinium will be researched and adaptability of them will be observed under the threats of the ocean-temperature rise, eutrophication, ocean -acidification and pathogens. The research will be helpful to the understanding the maintainability of coral-Symbiodinium symbionts to the environment changes. Strains of isolated Symbiodinium will be to construct the resource library of coral ecosystem and the research Symbiodinium relating the diversity and the adapatability will enrich data of China symbiotic algae.