木质素在海洋中的生物转化及其对海洋碳循环的影响

Biotransformation of lignin in the ocean and its impact on marine carbon cycle

摘要:

微型生物参与的海洋碳汇是海洋重要的储碳途径，可调节全球气候变化。木质素是地球上第二大光合而成的碳库，其在海洋中的生物地球化学过程与海洋碳循环密切相关。异养微生物所主导的代谢活动是木质素生物转化的主要途径。近年来，迅速发展的高通量测序技术与传统微生物技术相结合，在探索自然生境中木质素代谢菌群，发现木质素代谢新物种，挖掘相关功能基因等方面已取得一系列成果。然而绝大多数的研究主要集中于陆地生态系统，对于海洋生态系统的研究仍较少。陆源有机碳在海洋中的转化过程仍是一个“谜”，故解析海洋木质素碳转化是海洋碳循环研究的重要任务。本文综述了参与海洋木质素转化的功能微生物、木质素代谢机理以及微生物碳代谢活动与海洋碳汇过程的内在联系，为今后的研究提供参考。

关键词:木质素;微生物代谢;海洋;碳汇;微生物碳泵

Abstract:

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.

Key words:lignin;microbial metabolism;marine;carbon sink;microbial carbon pump