Collaborative Research: Multi-isotope and microbial ecology approaches to investigate sedimentary nitrous oxide production and consumption in the northern Benguela upwelling system

合作研究：采用多同位素和微生物生态学方法研究本格拉北部上升流系统沉积一氧化二氮的产生和消耗

• 批准号: 2342606
• 负责人: Annie Bourbonnais
• 金额: $ 55.06万
• 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: 2024-02-15 至 2027-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2342606&HistoricalAwards=false
• 关键词: Collaborative; Research; Multi; isotope; microbial

Nitrous oxide (N2O) is a potent greenhouse gas. It also plays an important role in the destruction of ozone. Nitrous oxide is produced by microorganisms in low-oxygen marine environments, which are important sources of N2O to the atmosphere. The northern Benguela Upwelling System off the west coast of Africa is one of the major oceanic Oxygen Deficient Zones (ODZs). Despite the recognition that the northern Benguela Upwelling System is a significant source of N2O, it remains an understudied ecosystem, particularly the sedimentary environment. In this study, a team of geochemists and microbial ecologists will investigate N2O cycling in northern Benguela Upwelling System sediments. The goal of the work is to describe the role of sediments both in this particular system and more broadly, in order to improve scientists’ ability to predict future emissions of this important greenhouse gas under changing environmental conditions. The project will support three undergraduates and three graduate students at the University of South Carolina (USC) and Florida State University. The project includes collaboration with scientists in South Africa and Namibia. The University of South Carolina will host students from each of these countries for six week internships as part of the project. The team is planning substantial outreach and educational activities in the U.S. and southern Africa.The contribution of different N2O producing and consuming processes in the northern Benguela Upwelling System will be determined with samples collected during two cruises of opportunity. Concentration, stable isotopic and isotopomer data, 15N-labeled rate measurements as well as molecular ecology data will be generated and synthesized to determine 1) the net sediment-water column flux of N2O, 2) N2O production and consumption rates for different processes, 3) controls by environmental conditions (e.g., oxygen (O2), hydrogen sulfide (H2S), and nutrient concentrations, O2 penetration depth, as well as organic matter elemental composition), and 4) the link between measured rates and the active processes that lead to N2O production by bacteria, archaea, and microbial eukaryotes, as well as bacterial and archaeal N2O consumption. This project will disentangle the relative contribution of these different processes by combining multi-isotope mass balance and meta-genomic/transcriptomic data. The study will generate a comprehensive dataset with new information on the contribution of archaea, bacteria (including large chemoautotrophic sulfide-oxidizing bacteria), fungi and other microbial eukaryotes for N2O production in relation to environmental conditions. The sediment data will complement water-column N2O concentration, stable isotope, isotopomer, rate measurement, and microbial ecology data collected concurrently as part of two other NSF). Sediment and water-column N2O data will be incorporated in a 3-dimensional nitrogen based physical/biogeochemical model. This data will be of interest to environmental scientists, including chemical and biological oceanographers and geochemical modelers, to help improve predictions of greenhouse gas emissions in marine environments.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）是潜在的温室气体。它在破坏臭氧中也起着重要作用。一氧化二氮是由低氧海洋环境中的微生物产生的，这是大气中N2O的重要来源。非洲西海岸附近的北部班格拉上升流系统是主要的海洋氧不足区（ODZ）之一。尽管人们认识到北部班格拉上升流系统是N2O的重要来源，但它仍然是一个知识的生态系统，尤其是沉积环境。在这项研究中，一个地球化学主义者和微生物生态学家团队将调查北班格拉上升流系统沉积物中的N2O骑行。这项工作的目的是为了提高科学家在不断变化的环境条件下预测这种重要的温室气体的未来排放的能力，以提高科学家预测这种重要的体积排放的能力。该项目将支持南卡罗来纳大学（USC）和佛罗里达州立大学的三名本科生和三名研究生。该项目包括与南非和纳米比亚科学家的合作。作为该项目的一部分，南卡罗来纳大学将接待来自每个国家 /地区的学生六周实习。该小组正在计划在美国和南部非洲进行大量的外展和教育活动。北本格拉上升流的不同N2O生产和消费过程的贡献将由两次机会巡游中收集的样本确定。 Concentration, stable isotopic and isotopomer data, 15N-labeled rate measurements as well as molecular ecology data will be generated and synthesized to determine 1) the net sediment-water column flux of N2O, 2) N2O production and consumption rates for different processes, 3) controls by environmental conditions (e.g., oxygen (O2), hydrogen sulfide (H2S), and nutrient concentrations, O2渗透深度以及有机物元素组成），以及4）测量速率与活跃过程之间的联系，导致细菌，古细菌和微生物真核生物以及细菌和细菌和古细菌N2O消耗。该项目将通过组合多等级质量平衡和元基因组/转录组数据来解散这些不同过程的相对贡献。该研究将生成一个全面的数据集，其中包含有关古细菌，细菌（包括大型化学自由硫化物氧化细菌），真菌和其他微生物真核生物在与环境条件有关的N2O生产的新信息。沉积物数据将补充水柱N2O浓度，稳定的同位素，同位素，速率测量和微生物生态学数据同时收集的作为一部分沉积物和水柱N2O数据将纳入基于3次氮的物理/生物地球化学模型。该数据将引起环境科学家的关注，包括化学和生物学海洋学家和地球化学建模者，以帮助改善海洋环境中温室气体排放的预测。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子优点和更广泛影响的审查标准来通过评估而被认为是珍贵的支持。