Collaborative Research: Deciphering the mechanisms of marine nitrous oxide cycling using stable isotopes, molecular markers and in situ rates

合作研究：利用稳定同位素、分子标记和原位速率破译海洋一氧化二氮循环机制

• 批准号: 2319096
• 负责人: Annie Bourbonnais
• 金额: $ 46.77万
• 依托单位: University of South Carolina at Columbia
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-01-15 至 2026-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2319096&HistoricalAwards=false
• 关键词: Collaborative; Research; Deciphering; mechanisms; marine

Nitrous oxide (N2O) is a powerful greenhouse gas, and a driver of ozone depletion in the stratosphere. Marine low-oxygen regions are important for N2O cycling and are a large source of N2O to the atmosphere. The Arabian Sea in the northwest Indian Ocean hosts one of the world’s largest low-oxygen zones, but it is less well-studied than other regions. In partnership with other researchers in the U.S. and India, this team will combine geochemical and microbial ecology approaches to study N2O cycling in the Arabian Sea. The project will support one postdoctoral investigator and two graduate students. Several undergraduate students will participate in the laboratory and at sea. One MS student from the Cochin University of Science and Technology (CUSAT), located in Kochi, Kerala, India will also be invited on at least one of the research cruises and participate in a 6-week internship in the Marine Stable Isotope Biogeochemistry Laboratory at the University of South Carolina. The U.S. postdoc and graduate students will participate in a 10-day regional training program in biogeochemistry for early career researchers in India. The project team will conduct public outreach from sea. They will also produce a freely available E-lecture on nitrogen cycling in low-oxygen zones.This project will advance current understanding of the microbiology and biogeochemistry of N2O production and consumption in marine oxygen deficient zones (ODZs) by quantifying rates and identifying major sources in the Arabian Sea using natural abundance stable isotopic and isotopomer data, 15N-labeled incubations, as well as genomic and metatranscriptomic methods. Field work is planned for the summers of 2024 and 2025. The first field activity will be during a cruise of opportunity funded by the Office of Naval Research (ONR) as part of the Arabian Sea Transition Layer (ASTraL): Exchange Across the Air-Sea Interface program. Four ship days supported through this NSF award will enable biogeochemical sampling at ten stations. In 2025, a four-week dedicated research expedition will focus on in-situ incubation rate experiments at two stations. Both ex-situ and novel in-situ 15N-incubations, which maintain natural trace-level O2 concentrations, will be used. Kinetic experiments will also be performed to determine the effect of substrate addition during 15N- labeled incubations. Combination of these approaches will reveal dominant pathways of N2O production and N2O consumption as well as the microorganisms mediating these processes along vertical O2 and productivity gradients in the Arabian Sea ODZ. Findings will allow inferences regarding larger scale forcings and impacts of future climate change.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.

一氧化二氮 (N2O) 是一种强大的温室气体，是平流层臭氧消耗的一个驱动因素，对于 N2O 循环非常重要，也是印度洋西北部阿拉伯海的一个重要来源。该地区拥有世界上最大的低氧区之一，但与其他地区相比，该地区的研究较少。该团队将与美国和印度的其他研究人员合作，将地球化学和地球化学相结合。研究阿拉伯海 N2O 循环的微生物生态学方法 该项目将支持一名博士后研究员和两名研究生参与实验室和海上工作。位于印度喀拉拉邦科钦的游轮公司也将受邀参加至少一次研究航行，并参加南卡罗来纳大学海洋稳定同位素生物地球化学实验室为期6周的实习。美国博士后和研究生将参加针对印度早期职业研究人员的为期 10 天的生物地球化学区域培训计划。他们还将制作免费的关于低氮循环的电子讲座。该项目将通过量化比率并利用天然物质识别阿拉伯海的主要来源，增进目前对海洋缺氧区 (ODZ) N2O 产生和消耗的微生物学和生物地球化学的了解。丰富的稳定同位素和同位素异构体数据、15N 标记孵化以及基因组和宏转录组学方法计划于 2024 年和 2025 年夏季进行。第一次实地活动将在海军研究办公室资助的机会巡航期间进行。 (ONR) 作为阿拉伯海过渡层 (ASTraL) 的一部分：通过该 NSF 奖项支持的跨空海接口交换计划将启用四船日。 2025 年，为期 4 周的专门研究考察将重点关注两个站的原位 15N 孵化率实验，以维持自然痕量水平的 O2 浓度。还将使用动力学实验来确定 15N 标记孵育过程中底物添加的影响，这些方法的组合将揭示 N2O 产生和 N2O 消耗的主要途径。以及在阿拉伯海 ODZ 中沿着垂直 O2 和生产力梯度介导这些过程的微生物的研究结果将允许对未来气候变化的更大规模的强迫和影响进行推断。该奖项反映了 NSF 的法定使命，并被认为值得通过使用评估来支持。基金会的智力价值和更广泛的影响审查标准。