The impact of oceanic microbial communities on marine biogeochemistry now and in the future

将在大西洋不同的海洋水柱环境中对微生物的多样性和功能进行跨学科研究，范围从营养丰富的海洋海湾贝德福德盆地到营养不良的海洋水域。海洋微生物对海洋中碳、氮、磷、铁等元素的循环有很大影响。特别是，氮循环在每一步都是由微生物调节的。这项研究将集中在海洋中氮素的循环，特别是氮气固定的重要性。铁的有效性在氮的生物转化中起着重要的作用，因为许多介导酶需要铁作为辅助因子。铁在大片海洋中是一种限制性营养物质，导致高溶解无机营养物质在表层水域中积累。重要的是要了解微生物是如何适应低铁的，这将是研究的第二个重点。将使用纯培养和微生物的自然组合，在基因组和转录水平上描述所研究的每个环境中的海洋微生物群落。这项研究将得出大西洋微生物群落功能遗传多样性的基线。这将为理解海洋微生物如何通过海洋表面和低层大气之间的反馈过程影响海洋生产力和气候变化提供一个框架。海洋生产力是鱼类生产的基础，鱼类种群管理需要了解控制营养循环和浮游植物生长的因素。这一结果将对评估和预测海洋微生物在未来海洋中的反应和进化具有重要意义。

Interdisciplinary research on the diversity and function of microorganisms will be conducted in diverse marine water column environments in the Atlantic Ocean, ranging from the Bedford Basin, a nutrient-rich marine embayment, to nutrient-poor oceanic waters. Marine microorganisms have a large impact on the cycling of elements such as carbon, nitrogen, phosphorus and iron in the ocean. In particular the nitrogen cycle is mediated at every step by microorganisms. The research will focus on the cycling of nitrogen in the ocean, more particularly on the importance of N2 fixation. The availability of iron plays an important role in the biological transformation of nitrogen because many mediating enzymes require iron as a co-factor. Iron is a limiting nutrient in large areas of the ocean, leading to the accumulation of high dissolved inorganic nutrients in surface waters. It is important to understand how microorganisms have adapted to cope with low iron and this will be a second focus of the research. The communities of marine microorganisms in each environment studied will be characterized at the genomic and transcriptomic levels using pure cultures and natural assemblages of microorganisms. The research will yield a baseline of the functional genetic diversity of the communities of microorganisms in the Atlantic Ocean. This will provide a framework to understand how marine microorganisms influence ocean productivity and climate change through feedback processes between the surface of the ocean and the lower atmosphere. Ocean productivity is at the basis of fish production, and management of fish stocks requires understanding the factors controlling nutrient cycles and phytoplankton growth. The results will be important to assess and predict how the marine microorganisms will respond and evolve in the future ocean.