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

跨学科研究微生物的多样性和功能将在大西洋不同的海洋水柱环境中进行，从贝德福德盆地，一个营养丰富的海洋港湾，到营养贫乏的海洋水域。海洋微生物对海洋中碳、氮、磷、铁等元素的循环有很大的影响。特别是氮循环在每一步都是由微生物介导的。这项研究将侧重于海洋中氮的循环，特别是氮固定的重要性。铁的可用性在氮的生物转化中起着重要作用，因为许多中介酶需要铁作为辅助因子。在海洋的大部分地区，铁是一种限制性营养物质，导致高溶解性无机营养物质在地表水中积累。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。研究的每个环境中的海洋微生物群落将使用纯培养和自然微生物组合在基因组和转录组水平上进行表征。这项研究将为大西洋微生物群落的功能遗传多样性提供一个基线。这将为了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，鱼类资源的管理需要了解控制营养循环和浮游植物生长的因素。这些结果对于评估和预测海洋微生物在未来海洋中的反应和进化将具有重要意义。

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.