EAGER: Collaborative Research: Detection limit in marine nitrogen fixation measurements - Constraints of rates from the mesopelagic ocean

EAGER：合作研究：海洋固氮测量的检测极限 - 中深海速率的限制

• 批准号: 1850588
• 负责人: Angelicque White
• 金额: $ 3.67万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-01 至 2020-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1850588&HistoricalAwards=false
• 关键词: EAGER; Collaborative; Research; Detection; limit

The availability of nitrogen is required to support the growth and production of organisms living in the surface of our global ocean. This element can be scarce. To alleviate this scarcity, a special class of bacteria and archaea, called nitrogen fixers, can derive the nitrogen needed for growth from nitrogen gas. This project would carefully examine one specific method for measuring nitrogen fixation that has been used recently to suggest the occurrence of small amounts of nitrogen fixation in subsurface ocean waters. If these reports are verified, then a revision of our understanding of the marine nitrogen cycle may be needed. The Ocean Carbon and Biogeochemistry program will be used as a platform to develop community consensus for best practices in nitrogen fixation measurements and detection of diversity, activity, and abundances of the organisms responsible. In addition, a session will be organized in a future national/international conference to communicate with the broader scientific community while developing these best practices.The goal of this study is to conduct a thorough examination of potential experimental and analytical errors inherent to the 15N2-tracer nitrogen fixation method, in tandem with comprehensive molecular measurements, in mesopelagic ocean waters. Samples will be collected and experimental work conducted on a cruise transect in the North Atlantic Ocean, followed by analytical work in the laboratory. The specific aims of this study are to (1) determine the minimum quantifiable rates of 15N2 fixation based on incubations of mesopelagic waters via characterization of sources of experimental and analytical error, and (2) seek evidence of presence and expression of nitrogen fixation genes via comprehensive molecular approaches on corresponding samples. The range of detectable rates and diazotroph activity from the measurements made in this study will be informative for the understanding of the importance of nitrogen fixation in the oceanic nitrogen budget.

需要氮的可用性来支持生活在全球海洋表面的生物体的生长和生产。这个元素可能很稀缺。为了缓解这种稀缺性，一类特殊的细菌和古细菌（称为固氮剂）可以从氮气中获取生长所需的氮。该项目将仔细研究一种测量固氮的具体方法，该方法最近被用来表明地下海水中存在少量的固氮。如果这些报告得到证实，那么我们可能需要修改对海洋氮循环的理解。海洋碳和生物地球化学计划将用作一个平台，以就固氮测量和负责生物体的多样性、活性和丰度检测的最佳实践达成社区共识。此外，将在未来的国家/国际会议中组织一次会议，以便在制定这些最佳实践的同时与更广泛的科学界进行交流。这项研究的目标是对 15N2- 固有的潜在实验和分析误差进行彻底检查示踪固氮方法，与综合分子测量相结合，在中层海水中进行。将在北大西洋的巡航横断面上收集样本并进行实验工作，然后在实验室进行分析工作。本研究的具体目的是（1）通过实验和分析误差来源的表征，确定基于中层水域孵化的 15N2 固定的最小可量化速率，以及（2）通过以下方式寻求固氮基因存在和表达的证据对相应样品进行综合分子方法。本研究中测量的可检测率和固氮生物活性范围将为了解海洋氮预算中固氮的重要性提供信息。

项目成果

Chasing after Non-cyanobacterial Nitrogen Fixation in Marine Pelagic Environments

追寻海洋远洋环境中的非蓝藻固氮作用

• DOI: 10.3389/fmicb.2017.01736
• 发表时间: 2017-09
• 期刊: Frontiers in Microbiology
• 影响因子: 5.2
• 作者: Moisander, Pia H.;Benavides, Mar;Bonnet, Sophie;Berman;White, Angelicque E.;Riemann, Lasse
• 通讯作者: Riemann, Lasse

A critical review of the 15 N 2 tracer method to measure diazotrophic production in pelagic ecosystems

对测量远洋生态系统固氮生产的 15 N 2 示踪剂方法的严格审查

• DOI: 10.1002/lom3.10353
• 发表时间: 2020-03
• 期刊: Limnology and Oceanography: Methods
• 作者: White, Angelicque E.;Granger, Julie;Selden, Corday;Gradoville, Mary R.;Potts, Lindsey;Bourbonnais, Annie;Fulweiler, Robinson W.;Knapp, Angela N.;Mohr, Wiebke;Moisander, Pia H.;et al
• 通讯作者: et al