Collaborative Research: Dissolved Phosphorus Processing by Trichodesmium Consortia: Quantitative Partitioning, Role of Microbial Coordination, and Impact on Nitrogen Fixation

在营养贫乏的开放海洋生态系统中，毛霉菌的菌落负责大部分的N2固定，最终为毛霉菌和更广泛的浮游生物群落的初级生产提供燃料。然而，在海洋的某些部分，溶解磷的稀缺限制了氮合木的固定速率。毛菌菌落采用一系列策略来减轻磷限制的影响，菌落中的表观菌群可能在磷获取中发挥重要作用。在这项研究中，来自伍兹霍尔海洋研究所和哥伦比亚大学的研究人员将使用宏基因组和超转录组测序来研究木霉（Trichodesmium consortia）的磷代谢是如何协调的，并辨别群体感应在磷获取和分配中的作用。本研究的结果有望扩大对Trichodesmium的理解，从一个单一的菌落，其主要功能是将CO2和N2固定在一个独特的浮游生物联合体中，这个联合体具有多样化、复杂和高度协调的整体代谢，对低营养上层海洋中无机和有机营养物质的循环有着深刻的控制。更广泛的影响：该项目将为代表性不足的少数民族研究生提供研究经验，并利用已建立的基于K-12标准的外展计划来提高儿童和公众的海洋素养。

Colonies of the cyanbacterium Trichodesmium are responsible for a large fraction of N2 fixation in nutrient-poor, open-ocean ecosystems, ultimately fueling primary production in both Trichodesmium and in the broader planktonic community. However, in some parts of the ocean, the scarcity of dissolved phosphorus limits rates of Trichodesmium N2 fixation. Trichodesmium colonies employ an arsenal of strategies to mitigate the effects of phosphorus limitation, and the consortia of epibiotic bacteria in the colonies may play a significant role in phosphorus acquisition. In this study, researchers from Woods Hole Oceanographic Institution and Columbia University will use metagenomic and metatranscriptomic sequencing to investigate how phosphorus metabolism is coordinated in Trichodesmium consortia, and to discern the role of quorum sensing in phosphorus acquisition and partitioning. Results from this study are expected to expand understanding of Trichodesmium from a monospecific colony whose primary function is fixing CO2 and N2 toward a unique planktonic consortium with a diverse, complex, and highly coordinated overall metabolism that exerts profound control over the cycling of inorganic and organic nutrients in the oligotrophic upper ocean.Broader Impacts: This project will provide research experience for an under-represented ethnic graduate student and take advantage of established K-12 standards-based outreach programs to increase ocean literacy in children and amongst the public.