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) 是一种强效温室气体，它对臭氧的破坏也起着重要作用。一氧化二氮是由低氧海洋环境中的微生物产生的，是北部本格拉上升流的重要来源。非洲西海岸附近的系统是主要的海洋缺氧区（ODZ）之一，尽管人们认识到北部本格拉上升流系统是重要的缺氧源。 N2O，它仍然是一个尚未被研究的生态系统，特别是沉积环境。在这项研究中，地球化学家和微生物生态学家团队将研究本格拉上升流系统沉积物中的 N2O 循环。这项工作的目标是描述沉积物在这方面的作用。该项目将支持南卡罗来纳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的科学家合作，作为该项目的一部分，南卡罗来纳大学将接待来自这两个国家的学生进行为期六周的实习。美国和南部非洲的教育活动。本格拉北部上升流系统中不同 N2O 产生和消耗过程的贡献将根据两次机会航行期间收集的样本、稳定同位素和同位素异构体数据来确定。将生成并综合 15N 标记的速率测量值以及分子生态学数据，以确定 1) N2O 的净沉积物-水柱通量，2) 不同过程的 N2O 生产和消耗速率，3) 环境条件的控制（例如，氧气 (O2)、硫化氢 (H2S) 和营养物浓度、O2 渗透深度以及有机物元素组成），以及 4) 测量的速率与导致的活性过程之间的联系该项目将通过结合多同位素质量平衡和宏基因组/转录组数据来阐明这些不同过程的相对贡献。生成一个全面的数据集，其中包含古细菌、细菌（包括大型化学自养硫化物氧化细菌）、真菌和其他微生物真核生物的贡献的新信息沉积物数据将补充同时收集的水柱 N2O 浓度、稳定同位素、同位素异构体、速率测量和微生物生态学数据（作为另外两个 NSF 沉积物和水柱 N2O 数据的一部分）。被纳入基于氮的 3 维物理/生物地球化学模型中，这些数据将引起环境科学家（包括化学和生物海洋学家以及地球化学建模者）的兴趣，以帮助改进。海洋环境中温室气体排放的预测。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。