陆地和淡水生态系统新型微生物氮循环研究进展

氮生物地球化学循环是地球物质循环的重要枢纽,是决定陆地生态系统生产力水平、水资源安全、温室气体生成排放的关键过程。氮循环是由微生物介导的一系列复杂过程,不同形态、价态氮化合物的转化分别由相应的功能微生物驱动完成。随着厌氧氨氧化、完全氨氧化等新型氮转化过程的相继报道和发现更新了人们对氮循环的认识。本文综述了陆地和淡水生态系统中厌氧氨氧化(anammox)、硝酸盐异化还原为铵(DNRA)、完全氨氧化(comammox)等新型氮循环过程的发生机制、热区分布及环境效应,并总结了这三种氮循环的相互关系。

Novel nitrogen cycles in terrestrial and freshwater ecosystems

Microbial carbon sequestration in the ocean plays an important role in marine carbon storage to alleviate the global climate change. Lignin is the second most abundant carbon pool formed by photosynthesis on earth. The biogeochemical process in the ocean, which is mediated by heterotrophic microorganisms, is closely related to the marine carbon cycle. In recent years, the rapidly developing high-throughput sequencing technology, together with the traditional microbial technology, provides insights into the lignin-degrading microbial community, novel lignin-metabolizing microbial species, and functional genes in open environments. However, numerous studies focused on the terrestrial ecosystem, rather than marine ecosystem. The biogeochemical process of such terrestrial organic carbon in the ocean remains elusive. Therefore, analyzing the marine lignin transformation is essential in the study of marine carbon cycle. This article reviews not only the marine microbes involved in the lignin conversion, the mechanism of lignin metabolism and the links between microbial carbon metabolism and marine carbon sink, but also provides further ideas in the future.