南海嗜热虫绿藻种群特征及其与珊瑚白化的因果关系研究

气候变化与人类活动正威胁着珊瑚礁生态系统。揭示共生藻与珊瑚物种之间的共生关系对预测珊瑚健康及制定珊瑚礁保护策略具有重要的意义。但目前相比共生虫黄藻的研究，共生虫绿藻还没有系统的分类命名，虫绿藻种群特征及其与珊瑚物种间的共生关系和珊瑚白化的因果关系还不清楚。最近，我们在国际权威期刊报道了一株与珊瑚白化相关的嗜热虫绿藻模式藻 Symbiochlorum hainanensis，该新属新种藻的发现为回答上述科学问题奠定了基础。在本项目中，我们拟借助野外调查结合室内培养、珊瑚组织切片、荧光原位杂技、高通量基因测序等研究方法与技术，分析嗜热虫绿藻种群多样性及其在我国南海近岸珊瑚礁区的分布特征；阐明不同珊瑚礁区嗜热虫绿藻与珊瑚物种之间的共生关系；揭示嗜热虫绿藻与珊瑚白化之间的因果关系。该研究将为深入认识嗜热虫绿藻种群特征与珊瑚礁区环境演变、丰富珊瑚-藻共生和珊瑚白化理论提供一定的数据支持和科学依据。

The coral reef ecosystem has being seriously influenced by global climate change and anthropogenic activity. Revealing the relationship of symbiotic algae with coral hosts is very important for predicting future fate of coral and developing strategies for protection coral reefs. Despite decades of reporting on the coral symbiotic zooxanthellae, the formal systematic taxonomy and population characteristics of coral symbiotic zoochlorallae have not kept pace, and its symbiotic relationship with coral hosts and coral bleaching is long overdue. Recently, we have found and reported an thermophilic Symbiochlorum hainanensis in an international leading journal, which is a new genus and a model strain of zooxanthellae related with coral bleaching. The discovery of the thermophilic S. hainanensis lay the foundation for answering above scientific questions. This project aims (1) to analyze the diversity of thermophilic S. hainanensis and its distrabutiion in nearshore coral reefs across the South China Sea; (2) to illustrate the symbiotic relationship between thermophilic S. hainanensis and coral hosts living in different coral reefs; (3) to reveal the causal relationship of coral bleaching with thermophilic S. hainanensis by field investigation, lab simulated experiment, coral tissue section and fluorescence in situ hybridization (FISH) and next generation sequencing (NGS). The results of this project will not only help understanding the correlationship of population characteristics of thermophilic S. hainanensis with the change of environmental factors of coral reefs, but will also provide important basic data and theoretical support for enriching coral-algae symbiosis and coral bleaching.