中文摘要：

深海热液微生物因其生存于海底极端环境，能够提供深部生物圈和生物地球化学信息而成为当今海洋科学领域关心的热点问题之一。本文以西南印度洋中脊热液羽状流水体中悬浮颗粒物为研究对象，选取典型的3个CTD采水站位，对离底42—500m的不同水层悬浮体过滤的滤膜进行扫描电镜观察和X射线能谱面扫描分析。结果表明，热液羽状流颗粒物中含有大量的微生物化石，包括丝状、球状、杆状和簇状等4种形态。对不同形态微生物化石能谱分析表明Si、O、Ca、Fe和Zn等元素在微生物化石中都有高值出现，其中丝状体中具有Ti和Mn的高值出现，球状体中Ba具有高值，说明微生物化石化过程中不同类型的微生物体对金属元素的选择性吸收，钙化和铁硅酸盐岩化是微生物化石化的主要机制。微生物化石在羽状流中的分布状况能够提供活动热液喷口的空间信息，为我们寻找喷口提供帮助。

英文摘要：

By scanning electron micrography and X-ray energy spectrometer, particulate materials obtained through filtering the seawater taken from the hydrothermal plume region in the Southwest Indian Ridge were analyzed. Four types of microorganisms including filaments, spheric, rod-shaped and clustered types has been found in these sampies. Si,O,Ca,Fe and Zn contents are high commonly in different types, while Ti, Mn and Ba contents are high in filamentous and spherical ones, respectively, indicating that there is a selective absorption of different elements. Fe-silicatization and calcification are the main mechanism of microorganism fossilization. The distribution of microorganisms in hydrothermal plume provide the spatial information of seafloor active vents and will help to find new vents.