The Microobial Nitrogen Pump: Coupling 14C and Compound-specific Amino Acids to Understand the Role of Microbial Transformations in the Refractory Ocean DON Pool

溶解有机氮是现代海洋氮循环中最重要但可能最不为人所知的组成部分之一。虽然溶解有机氮是固定氮和看似生物可利用氮的主要活性库，但同时海洋中大部分溶解有机氮库显然也无法被生物利用。最近，出现了“微生物碳泵”的想法，重新关注微生物作为形成生物可利用的溶解材料的主要媒介。然而，微生物在生物可利用溶解性有机氮转化中的作用仍然缺乏。为了填补这方面的知识空白，来自加州大学圣克鲁斯分校的研究人员将采用一系列新的分析方法来测试微生物来源和转化在海洋生物可利用的溶解有机氮库形成中的作用。这项研究的结果将解决化学海洋学和海洋氮循环的主要未知之一。更广泛的影响：这项建议将为海洋学家提供新的工具，以测试在海洋迅速变化的世界中微生物有机物封存的想法。高中，本科，研究生和博士后教育将通过积极参与实验室，现场和数据合成活动得到进一步发展。

Dissolved organic nitrogen is one of the most important - but perhaps least understood - components of the modern ocean nitrogen cycle. While dissolved organic nitrogen represents a main active reservoir of fixed and seemingly biologically-available nitrogen, at the same time most of ocean's dissolved organic nitrogen pool is also apparently unavailable for use by organisms. Recently, the idea of the "Microbial Carbon Pump" has emerged, providing a renewed focus on microbes as primary agents for the formation of biologically-available dissolved material. However, the role that microbes play in transformation of biologically-available dissolved organic nitrogen is still lacking. In order to fill gaps in this knowledge, researchers from the University of California Santa Cruz will apply a series of new analytical approaches to test the role of microbial source and transformation in formation of the ocean's biologically-available dissolved organic nitrogen pool. Results from this study will address one of the major unknowns of both chemical oceanography and the ocean nitrogen cycle.Broader Impacts:This proposal will provide oceanographers new tools to test ideas of microbial organic matter sequestration in a world where the oceans are rapidly changing. High school, undergraduate, graduate and post-doctoral education will be furthered through active participation in lab, field, and data synthesis activities.