大洋最小含氧带生物地球化学循环及微生物多样性研究进展

Advances in biogeochemical cycles and microbial diversity in the oxygen minimum zone

摘要:

大洋的最小含氧带（oxygen minimum zones，OMZs）具有特殊的水动力和氧含量特征，该区域是氮流失的主要场所，也是各类生化反应发生的重要区域。OMZs的存在会对浮游生物的丰度、多样性、分布模式及呼吸方式产生较大影响。大洋OMZs中存在广泛的反硝化、厌氧氨氧化、甲烷厌氧氧化和隐性厌氧硫氧化作用等都是海洋物质循环的关键环节。全球海洋OMZs的规模在人类活动和全球变暖等因素的影响下也呈现出逐渐扩大的趋势。低氧环境的变化可以通过微生物多样性和群落结构稳定性进行判断，因此了解该区域的多样性水平是十分必要的。现有研究虽然对海洋OMZs的生物地球化学循环、微生物多样性和生态效应有了一定的认识，但对该区域总体情况和微生物生态学研究现状的系统性综合论述还较少，对海洋低氧环境的微生物活性、群落结构稳定性和分子代谢过程的研究还有较大的探讨空间。本文介绍了海洋低氧环境的分布情况和生态环境效应，全面且详细地论述了OMZs内各物质循环过程和微生物多样性的研究现状，指出尚未很好解决的生态学问题。

关键词:海洋低氧环境;微生物;生物地球化学循环;OMZs;微生物多样性

Abstract:

Oxygen minimum zones (OMZs) are characterized with special hydrodynamic and vertical oxygen profiles and are the main areas of nitrogen loss through fascinating biogeochemical reactions. The presence of OMZs affects the abundance, diversity, distribution, and respiration of plankton. There are some extensive reaction in OMZs, such as denitrification, anammox, anaerobic oxidation of methane, and cryptic anaerobic sulfide oxidation, which are the key parts of the ocean material cycle. Under the influence of human activities and global warming, the area of the OMZs is also expanding. The changes of the ocean hypoxic environment can be determined by microbial diversity and the stability of the community structure, so it is necessary to understand the diversity level of the area. With limited understanding of the biogeochemical cycle and microbial diversity in OMZs, the comprehensive discussion on the biogeochemical, microbiological and ecological features of OMZs remains to be rare. Particularly, there are still many gap knowledge on the microbial activity, community structure stability and metabolic network in these hypoxic environments of the world's ocean. This paper summarized the distribution and biogeochemical features of these marine hypoxic environments, and particularly discussed nutrient cycling processes and microbial communities in OMZs. Finally, it identified the current information gap and pointed out the future research directions in these interesting ocean habitats.

Key words:marine hypoxic environments;microorganism;biogeochemical cycle;OMZs;microbial diversity