Collaborative Research: Methane efflux from river influenced coastal marine sediments

合作研究：河流甲烷外流影响沿海海洋沉积物

• 批准号: 2220309
• 负责人: Christof Meile
• 金额: $ 19.93万
• 依托单位: University of Georgia Research Foundation Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-10-01 至 2025-09-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2220309&HistoricalAwards=false
• 关键词: Collaborative; Research; Methane; efflux; river

Collaborative Research: Methane efflux from river influenced coastal marine sedimentsMethane is a strong greenhouse gas and the amount of methane in the atmosphere is increasing. Large amounts of methane are present in sediments. Thus, understanding how much methane is released from sediments is a key first step for improving estimates of methane emissions. Coastal sediments are thought to be large sources of methane to the overlying water and potentially the atmosphere. Yet, fluxes of methane from coastal environments are poorly known. This project will measure methane fluxes from coastal sediments into the waters of the Gulf of Mexico. Methane is produced in sediments when microorganisms break down organic matter and from geological sources. However, the amount of methane released from sediments can be reduced by microorganisms that oxidize methane near the sediment surface where oxygen is present (aerobic oxidation) and deep in the sediment where oxygen is not present (anaerobic oxidation). This study focuses on environments where the aerobic oxidation of methane is the key process that prevents its release to the water column. Results from this project will help identify areas of the coastal ocean that are significant sources of methane release. This work is timely, as river-influenced marine sediments are sensitive to anthropogenic activities and global climate change. Scientists involved in this study will translate the findings into useful information for carbon cycle scientists, policy makers, students, teachers, and the public. They will work with education and outreach programs at Louisiana Universities Marine Consortium, University of Georgia, and Louisiana State University, and provide training to scientists from undergraduate to postgraduate levels.High sedimentation rates, like those found near rivers, can drive methane efflux from sediments, as evidenced by elevated methane concentrations in bottom waters. Observational data suggest that sediments from river influenced shallow shelf regions with low dissolved oxygen concentrations in the water column emit more methane to the water column than typical continental shelf sediments. This project combines benthic flux measurements, geochemistry and rate analysis into a reaction-transport model that will evaluate environmental influences on benthic processes. The team of scientists will measure benthic fluxes of oxygen and methane using an in situ lander, and sediment micro-profiles of oxygen and sulfide. Sedimentation and mixing rates will be determined using naturally occurring radioisotopes. Sulfate reduction and methane oxidation rates will be determined using radiotracers and a broad suite of contextual geochemical analysis will be performed. During two cruises off the southeastern coast of Louisiana, a total of 5 sites will be targeted. The data synthesis will help refine our understanding of the interactions between rivers, marine sediments, and methane releases from marine sediments. The project supports the development of an early career investigator and will provide training for one postdoctoral associate, two graduate students, three research assistants. This effort will leverage the LUMCON REU site program to support at least one student per year. The education goals emphasize informal education through outreach, formal education in the classroom, and authentic research experiences for community college students. Many of the activities emphasize the importance of communicating information to the scientific community, students, policy makers, and the general public.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.

协作研究：来自河流影响的沿海海洋沉积物甲烷的甲烷外排是一种强烈的温室气体，大气中的甲烷量正在增加。沉积物中存在大量甲烷。因此，了解从沉积物中释放多少甲烷是改善甲烷排放估计值的关键第一步。沿海沉积物被认为是甲烷的大量来源，可能是大气层的大气层。然而，沿海环境中甲烷的通量鲜为人知。该项目将测量从沿海沉积物进入墨西哥湾水域的甲烷通量。当微生物分解有机物和地质来源时，在沉积物中产生甲烷。但是，从沉积物中释放出的甲烷量可以通过微生物减少，这些微生物在存在氧气（有氧氧化）的沉积物表面附近氧化甲烷，而在不存在氧气的沉积物中深处（厌氧氧化）。这项研究的重点是甲烷有氧氧化是阻止其释放到水柱的关键过程的环境。该项目的结果将有助于确定沿海海洋地区的重要来源，这些区域是甲烷释放的重要来源。这项工作是及时的，因为受河流影响的海洋沉积物对人为活动和全球气候变化敏感。参与这项研究的科学家将这些发现转化为碳循环科学家，决策者，学生，老师和公众的有用信息。他们将与路易斯安那大学海洋联盟，佐治亚大学和路易斯安那州立大学一起与教育和外展计划合作，并向从本科到研究生级别的科学家提供培训。高繁殖率，例如在河流附近发现的那些，可以使甲烷外排从恒星中驱动甲烷外排，这是甲烷浓度较高的甲烷浓度，而甲烷浓度是甲烷浓度。观察性数据表明，来自河流的沉积物影响了水柱中溶解氧浓度低的浅层架区，比典型的大陆架沉积物发射到水柱上的甲烷更多。该项目将底栖通量测量，地球化学和速率分析结合在一起，将其评估对底栖过程的影响。科学家团队将使用原位降落器以及氧气和硫化物的沉积物微型矿物质来测量氧气和甲烷的底膜通量。沉积和混合速率将使用天然存在的放射性同位素确定。硫酸盐还原和甲烷氧化速率将使用放射性示例确定，并将进行一系列环境地球化学分析。在路易斯安那州东南海岸的两次巡游中，总共将有5个地点。数据综合将有助于我们了解我们对海洋沉积物中河流，海洋沉积物和甲烷释放之间相互作用的理解。该项目支持一名早期职业调查员的发展，并将为一名博士后同学，两名研究生，三名研究助理提供培训。这项工作将利用Lumcon REU网站计划每年至少支持一个学生。教育目标通过在课堂上的外展，正规教育以及为社区大学生的真实研究经验强调非正式教育。许多活动都强调了将信息传达给科学界，学生，政策制定者和公众的重要性。该奖项反映了NSF的法定使命，并使用基金会的知识分子优点和更广泛的影响审查标准，认为值得通过评估来获得支持。