海洋地质与环境重点实验室知识库

为了解海洋微生物对多金属结核成矿金属元素的矿化机制，揭示西太平洋区域大洋铁锰结核的生物成矿特征和生物成因过程，进一步阐明微生物活动在大洋铁锰结核形成过程中发挥的作用，充实大洋铁锰结核的生物成矿理论。通过分析结核样品内部的微生物群落结构特征，并结合实验室模拟生物矿化实验，开展了铁锰结核微生物成矿过程的研究。

本研究通过基于16s rDNA的微生物多样性分析，研究了不同区域铁锰结核以及结核与沉积物之间微生物群落结构的差异，并分别选取芽孢八叠球菌（Paenisporosarcina）和亚硫酸杆菌（Sulfitobacter）对Fe和Mn的生物矿化过程开展了详细的实验室模拟实验。通过磺基水杨酸分光光度法和电感耦合等离子体发射光谱（ICP-OES），分析生物矿化过程中金属元素浓度变化及其迁移过程；综合运用透射电镜（TEM）、扫描电镜（SEM）和能谱仪（EDS）等多种方法，对细菌表面形态和生物成矿的矿物组成进行分析。

本研究主要获得了以下结果：（1）铁锰结核与其周围沉积物之间微生物群落结构的差异小于不同区域的结核之间的差异。而结核与其周围沉积物相比，有着更高的微生物丰度和多样性，并且两者中的微生物群落结构有明显差异。此结果暗示结核中存在某些独特的生物代谢活动，其中某些微生物可能与Fe、Mn等金属元素的地球化学循环有关；（2）以芽孢八叠球菌为代表的海洋微生物在中性有氧条件下，对Fe产生了明显的矿化作用，在微生物菌体表面生成了铁氧化物（或氢氧化物）矿物颗粒；（3）通过Mn氧化菌筛选实验挑选出的亚硫酸杆菌能在中性有氧环境中氧化Mn²⁺，并在细菌细胞之间生成直径为数微米的Mn氧化物矿物。

基于此研究，通过开展大洋铁锰结核与沉积物中微生物多样性分析，表明两者微生物群落结构有显著差异，结核中有更为强烈的微生物活动，并且与金属元素的循环过程密切相关。同时，实验室模拟实验的结果揭示了微生物矿化作用对Fe、Mn生物矿物形成的贡献，表明微生物活动对大洋铁锰结核形成有重要作用。

In order to investigate the mineralization mechanism of marine microbes on the mineralization of polymetallic nodules, to reveal the biomineralization characteristics and biomineralization processes of oceanic ferromanganese nodules in the Western Pacific, to clarify the role of microbial activities in the formation of oceanic ferromanganese nodules, and to enrich the biological mineralization theory of oceanicferromanganese nodules. Researches on the microbial mineralization processes of ferromanganese nodules were carried out, through the analysis of the microbial community structure characteristics inside the nodule samples, combined with laboratory simulation biomineralization experiments.

In this study, the differences of microbial community structure between ferromanganese nodules and sediments in diverse regions were studied through 16s rDNA-based microbial diversity analysis, in addition, Paenisporosarcina and Sulfitobacter were selected respectively to carry out detailed laboratory simulation experiments on the biomineralization process of Fe and Mn. Through sulfosalicylic acid spectrophotometry and inductively coupled plasma emission spectroscopy (ICP-OES), the metallic elements concentration change and the migration process of metal elements in the process of biomineralization were measured; the surface morphology of bacteria and the composition of biominerals were analyzed by comprehensive use of transmission electron microscope (TEM), scanning electron microscope (SEM) and energy spectrometer (EDS) and other methods.

Base on above studies, some conclusions were obtained as follows: (1) The difference in microbial community structure between ferromanganese nodules and the surrounding sediments is smaller than that between nodules in different regions. Compared with the surrounding sediments, nodules have higher microbial abundance and diversity, and there are obvious differences in the microbial community structure between nodules and surrounding sediments. These results may indicate that there are some unique biological metabolic activities in nodules, and some microorganisms may be related to the geochemical cycle of metal elements such as Fe and Mn; (2) Marine microorganisms represented by Paenisporosarcina have a significant mineralization effect on Fe in a neutral aerobic environmental conditions, and iron (hydrogen) oxide mineral particles are formed on the surface of microbial cells; (3) The Sulfitobacter selected through the Mn oxidizing bacteria screening experiment can oxidize Mn²⁺ in a neutral aerobic environment, Mn oxide minerals with a diameter of several microns are generated between the bacterial cells.

Based on this research, through the analysis of the microbial diversity in the oceanic ferromanganese nodules and sediments, it is shown that there are significant differences in the microbial community structure between the two, and there are more intense microbial activities in the nodules, which are closely related to the cycle of metal elements. Moreover, the results of laboratory simulation experiments revealed the contribution of microbial mineralization to the formation of Fe and Mn biominerals, indicating that microbial activities play an important role in the formation of oceanic ferromanganese nodules.