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，是平流层中臭氧消耗的驱动因素。海洋低氧区域对于N2O骑自行车很重要，并且是N2O的重要来源。印度洋西北部的阿拉伯海是世界上最大的低氧区域之一，但它比其他地区的研究不足。该团队与美国和印度的其他研究人员合作，将结合地球化学和微生物生态学方法来研究阿拉伯海的N2O循环。该项目将支持一名博士后调查员和两名研究生。几位本科生将参加实验室和海上。位于印度喀拉拉邦高知的科钦科学技术大学（CUSAT）的一名女士也将受邀参加至少一项研究巡游，并参与南卡罗来纳大学的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一项为期10天的印度职业研究人员生物地球化学的区域培训计划。项目团队将从海上进行公共宣传。 They will also produce a free 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 definitive 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基因组和元文字方法。计划在2024年和2025年的夏季进行现场工作。第一个现场活动将是在海军研究办公室（ONR）资助的机会巡游中，这是阿拉伯海过渡层的一部分（星际）：跨海 - 海上界面界面的交换。通过该NSF奖支持的四个船只天将在十个站点进行生物地球化学采样。 2025年，为期四周的专门研究探险将重点放在两个站点的原位孵化率实验上。将使用自然痕量o2浓度的前坐骨和新型原位15N融合。还将进行动力学实验，以确定15N标记的孵育期间底物添加的效果。这些方法的组合将揭示N2O生产和N2O消耗的主要途径以及沿垂直O2的这些过程的微生物和阿拉伯海ODZ的生产力梯度介导的微生物。调查结果将允许对更大规模的强迫和未来气候变化的影响进行推断。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子优点和更广泛的影响审查标准来评估诚实地支持了支持。