南太平洋环流区是全球最大的大洋环流区，在全球大洋中其有机质沉积速率最低，且全部沉积层均有氧气穿透。综合大洋钻探计划（IODP）329航次对南太平洋环流区洋底进行了首次钻探，项目申请人以微生物学家的身份参加了该航次并获得了航次样品。本项目拟利用荧光定量PCR及16S rDNA测序等技术检测环流区洋底沉积物中古菌和细菌的丰度、群落结构及与洋壳年龄和地质环境的相关性；采用GeoChip环境功能基因芯片和宏基因组测序等技术分析沉积物中微生物的功能基因及代谢潜能；分析环流区表层及底层海水中微生物的群落结构及功能活性，阐明其对海洋学因素（如表层海洋生产力）变化的应答；对从宏基因组测序及海洋新菌基因组测序中获得的新型功能基因，研究其功能活性并分析微生物的新代谢通路。通过以上研究认识南太平洋环流区洋底沉积物及海水中微生物群落演化及功能活性，进而揭示低沉积速率大洋洋底微生物活动对全球生物地球化学循环的影响。

The South Pacific Gyre is the largest of the ocean gyres. The subseafloor sediment of this region has the lowest organic burial rates in the ocean, and dissolved oxygen is present throughout the entire sediment sequence. The seafloor of the South Pacific Gyre has been drilled by Integrated Ocean Drilling Program (IODP) Expedition 329 for the first time, and the applicant of this project attended this expedition as a microbiologist and obtained precious samples of the expedition. In this project, the abundance and community composition of archaea and bacteria in the subseafloor sediment of the South Pacific Gyre will be determined by real-time PCR and 16S rDNA sequencing, and their correlation with the seafloor crust age and the oceanographic properties will be analyzed. The functional gene diversity and metabolic potential of microbial communities in the subseafloor sediment will be investigated by the GeoChip functional gene microarray and the metagenomic sequencing. The microbial community compositions and functional activities in the surface and bottom seawater of the South Pacific Gyre will be documented, and their response to the variation of oceanographic factors (such as surface ocean productivity) will be analyzed. Activities of novel functional genes obtained from metagenomic sequencing and new bacterial species will be studied, and novel metabolic pathways will be investigated. Based on above studies, the microbial community evolution and functional activity of the subseafloor sediment and seawater in the South Pacific Gyre will be acknowledged, and the effect of microbial activity in the most organic poor sediment of the world ocean upon the global biogeochemical cycle will be uncovered.