Collaborative Research: Microdiversity drives ecosystem function: SAR11 bacteria as models for oceanic nitrogen loss

该项目研究低氧可用性如何影响海洋中最丰富的微生物群体之一SAR11细菌的生物多样性和生态作用。这项工作涉及在热带北太平洋东部的一系列氧气和营养水平的海洋学采样。使用基因组，微生物和生物地球化学方法的组合，该研究确定了SAR11菌株多样化为单独的生态位和物种的机制，并在生物化学上对生态系统做出贡献，可能是通过从海水中去除氮。该项目使下一代研究人员和教育工作者，特别是那些来自代表性不足的少数群体的研究人员和教育工作者，能够使用海洋学，基因组学和微生物学概念来应对当代科学挑战。这一目标是通过生物信息学研讨会，目标是从波多黎各，中学教师培训研讨会，初中或高中教师实习研究员的实验室系统的本科生的组合来实现。这一多方面的研究和教育议程填补了我们对海洋生物多样性认识的空白，确定了SAR11细菌对低氧海洋营养和碳循环的贡献，并为研究其他生态系统中的微生物过程提供了经验教训和分析工具。目的1采用比较宏基因组和单细胞基因组分析，以确定代谢特性，区分SAR 11进化枝从低氧区域和选择过程或跨进化枝的基因流操作。目的2结合微生物转录组学，培养实验与同位素示踪剂，培养划定氧气和营养条件，定义每个SAR 11进化枝的生态位空间和相关的SAR 11基因转录与社区的生化结果，包括氮损失通过反硝化。通过以基因组学为重点的大学生讲习班和新的教师培训教育单元，包括侧重于海洋环境变化下微生物重要性的实验室单元，传播这些目标的成果和用于探测微生物微多样性的信息学方法。该项目的数据、手稿和信息学工作流程都是公开的。研究结果对于解决创造和维持海洋微生物多样性的过程至关重要，并为预测多样性如何影响生态系统过程的生物地球化学模型提供信息。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project studies how low oxygen availability influences the biodiversity and ecological role of SAR11 bacteria, one of the most abundant microbial groups in the ocean. The work involves oceanographic sampling across a range of oxygen and nutrient levels in the Eastern Tropical North Pacific Ocean. Using a combination of genomic, microbiological, and biogeochemical methods, the study identifies the mechanisms by which SAR11 strains diversify into separate niches and species and contribute biochemically to the ecosystem, likely through removing nitrogen from seawater. The project equips the next generation of researchers and educators, notably those from underrepresented minority groups, to use oceanographic, genomic, and microbiological concepts to meet contemporary scientific challenges. This goal is met through a combination of bioinformatic workshops that target undergraduate students from the University System of Puerto Rico, middle school teacher-training workshops, and middle or high school teacher internships in the investigator’s labs. This multifaceted research and educational agenda fills a gap in our understanding of marine biological diversity, identifies the contribution of SAR11 bacteria to nutrient and carbon cycles in low oxygen oceans, and provides lessons and analytical tools to study microbial processes in other ecosystems.This project has two aims. Aim 1 employs comparative metagenomic and single-cell genomic analyses to identify metabolic properties that distinguish SAR11 clades from low oxygen regions and processes of selection or gene flow operating across the clades. Aim 2 combines microbial transcriptomics, incubation experiments with isotope tracers, and culturing to delimit the oxygen and nutrient conditions that define the niche space of each SAR11 clade and to correlate SAR11 gene transcription with community biochemical outcomes, including nitrogen loss through denitrification. The results of these aims and the informatic methods used to probe microbial microdiversity are disseminated through genomics-focused undergraduate workshops, and new teacher-training educational modules, including lab-based modules focused on the importance of microorganisms under environmental change in the oceans. Data, manuscripts, and informatics workflows from this project are made publicly available. The results are critical for resolving the processes that create and sustain microbial diversity in the oceans and informing biogeochemical models that predict how diversity influences ecosystem processes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.