Department of Ocean Sciences, University of California, Santa Cruz, CA 95003, USA.
Marine and Environmental Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA.
Science. 2020 May 15;368(6492). doi: 10.1126/science.aay9514.
Nitrogen fixation, the reduction of atmospheric dinitrogen gas (N) to ammonia, is critical for biological productivity but is difficult to study in the vast expanse of the global ocean. Decades of field studies and the infusion of molecular biological, genomic, isotopic, and geochemical modeling approaches have led to new paradigms and questions. The discovery of previously unknown N-fixing (diazotrophic) microorganisms and unusual physiological adaptations, combined with diagnostic distributions of nutrients and their isotopes as well as measured and modeled biogeographic patterns, have revolutionized our understanding of marine N fixation and its role in the global nitrogen cycle. Anthropogenic upper-ocean warming, increased dissolved carbon dioxide, and acidification will affect the distribution and relative importance of specific subgroups of N fixers in the sea; these changes have implications for foodwebs and biogeochemical cycles.
固氮作用，即将大气中的氮气（N）还原为氨，对生物生产力至关重要，但在广阔的全球海洋中很难进行研究。几十年来的野外研究以及分子生物学、基因组学、同位素和地球化学建模方法的引入，带来了新的范例和问题。以前未知的固氮（固氮）微生物的发现和不寻常的生理适应，加上营养物质及其同位素的诊断分布以及测量和建模的生物地理模式，彻底改变了我们对海洋固氮作用及其在全球氮循环中的作用的理解。人为的上层海洋变暖、溶解二氧化碳增加和酸化将影响海洋中特定固氮分组的分布和相对重要性；这些变化对食物网和生物地球化学循环有影响。
