Intracellular DOM: Fate and flux at the microbial nodes of C and N cycles in the ocean, with a focus on the primary producer Prochlorococcus

智力优势：微生物是海洋微粒有机物库的关键组成部分；它们是无机物质和有机物质之间、溶解有机物和颗粒有机物之间相互转化的节点。虽然已经报道了初级和次级生产的大量速率，但海洋学界目前对微生物细胞内发生的转化代谢过程缺乏了解，这些过程最终决定了它们在碳和氮循环中的作用。本研究将利用液相色谱-串联质谱的代谢组学和转录组学来研究单细胞海洋蓝藻原绿球藻（Prochlorococcus）体内碳和氮的命运和通量。这种生物是最丰富的光合海洋浮游植物，占开放海洋初级产量的50%。因此，本研究将提高对开放海洋中碳和氮循环的认识，并提供原绿球藻生理学的代谢组学和转录组学数据。更广泛的影响：考虑到本研究的更广泛影响，研究生和本科生将有机会参与这个多学科项目。除了这些教育活动外，还将通过在实验室接待学生、举办公开研讨会和进一步编制教育补充资料等方式，向小学12年级学生以及代表性不足和处境不利的群体进行外联。

Intellectual Merit: Microbes are key components of the marine particulate organic matter pool; they serve as nodes of inter-conversion between inorganic and organic materials, and between dissolved and particulate organic matter. While bulk rates of primary and secondary production have been reported, the oceanographic community currently lacks an understanding of the transformative metabolic processes that occur within microbial cells and ultimately dictate their roles in carbon and nitrogen cycling. This study will bring the power of liquid chromatography-tandem mass spectrometry based metabolomics and transcriptomics to bear on the fate and flux of carbon and nitrogen within the unicellular marine cyanobacterium, Prochlorococcus. This organism is the most abundant photosynthetic marine phytoplankter, accounting for 50% of primary production in the open ocean. This study will therefore improve understanding of carbon and nitrogen cycling in the open ocean and provide metabolomics and transcriptomics data on Prochlorococcus physiology. Broader Impacts: With regard to the broader impacts of this study, graduate and undergraduate students will be given the opportunity to participate in this multidisciplinary project. Beyond these educational activities, outreach to P-12 school audiences as well as underrepresented and disadvantaged groups will be conducted by hosting students in the laboratory, giving public seminars, and further developing educational supplements.