EAR-PF Salinity Influence on Methane Emissions from Tidal Wetlands Determined by Clumped Isotopes

通过聚集同位素测定 EAR-PF 盐度对潮汐湿地甲烷排放的影响

• 批准号: 2052834
• 负责人: Mojhgan Haghnegahdar
• 金额: $ 17.4万
• 依托单位: Haghnegahdar Mojhgan
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2052834&HistoricalAwards=false
• 关键词: EAR; PF; Salinity; Influence; Methane

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). Methane (CH4) is the most abundant organic gas in Earth’s atmosphere, and a greenhouse gas. The EPA estimates indicate that methane accounts for 10% of national greenhouse gas emissions (www.epa.gov/ghgemissions). Methane emissions to the atmosphere include both anthropogenic and natural sources. Of these, wetlands not only play a significant role in the global methane budget, but are also one of the sources with the greatest associated uncertainties. This proposal focuses on wetland methane emissions within the Chesapeake Bay region. This region consists of a variety of environments that produce methane, most notably freshwater tidal wetlands. The proposed research will help characterize the regional methane budget and role of microbial processes that are driven by both natural and anthropogenic forcing of estuarine salinity. This work will support a longer-term project to construct a regional methane cycle model and to model atmospheric methane in this part of the world. Understanding the evolution of the atmospheric methane budget has important implications for local tidal wetlands restoration projects and national climate change policy decisions.Estimates of methane emissions from tidal wetlands are subject to high uncertainty and commonly suffer from the lack of information, but essential for determining the atmospheric methane budget and its change over time. The proposed research will evaluate the role of salinity (seasonal and regional changes) on microbial methane production and consumption in Maryland wetlands using new methane isotopologue fingerprinting approach. This work will document signatures of carbon and hydrogen in clumped isotopes that depend on varying environmental conditions and seek to develop an isotopologue tracer to track rates of microbial methane production and consumption influenced by environmental factors in different tidal wetlands systems. Using doubly substituted methane isotopologues (clumped isotopes) offers an additional way to resolve uncertainties about the biogenic methane formation pathways under various environmental conditions including the salinity and electron acceptors variability. This study will also address key questions regarding the pathways in methane production and consumption by microbes under the influence of various salinity regimes in tidal wetland systems. The work is a combination of in-situ methane measurements and laboratory (under controlled conditions) experiments. The results of this study will improve our understanding of the role of tidal wetlands in methane budget in Maryland and will be beneficial in environmental policy decisions.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.

该奖项全部或部分根据2021年美国救援计划法案（公法117-2）资助。甲烷（CH 4）是地球大气中最丰富的有机气体，也是一种温室气体。美国环保署估计，甲烷占全国温室气体排放量的10%（www.epa.gov/ghgemissions）。向大气排放的甲烷包括人为和自然来源。其中，湿地不仅在全球甲烷收支中发挥着重要作用，而且也是相关不确定性最大的来源之一。该提案的重点是切萨皮克湾地区的湿地甲烷排放。该地区由各种产生甲烷的环境组成，最著名的是淡水潮汐湿地。拟议的研究将有助于表征区域甲烷预算和微生物过程的作用，这是由自然和人为强迫河口盐度。这项工作将支持一个长期项目，以建立一个区域甲烷循环模型，并模拟世界这一地区的大气甲烷。了解大气甲烷收支的演变对当地潮汐湿地恢复项目和国家气候变化政策决策具有重要意义。潮汐湿地甲烷排放量的估计具有很高的不确定性，通常受到信息缺乏的影响，但对于确定大气甲烷收支及其随时间的变化至关重要。拟议的研究将评估盐度（季节和区域变化）对微生物甲烷生产和消费的作用在马里兰州湿地使用新的甲烷同位素指纹方法。这项工作将记录依赖于不同环境条件的聚集同位素中的碳和氢的签名，并寻求开发同位素示踪剂来跟踪不同潮汐湿地系统中受环境因素影响的微生物甲烷生产和消费速率。使用双取代的甲烷同位素体（成团同位素）提供了一种额外的方式来解决在各种环境条件下，包括盐度和电子受体的变异性的生物甲烷形成途径的不确定性。这项研究还将解决关键问题，在潮汐湿地系统中的各种盐度制度的影响下，微生物的甲烷生产和消费的途径。这项工作是现场甲烷测量和实验室（在受控条件下）实验的结合。这项研究的结果将提高我们对潮汐湿地在马里兰州甲烷预算中的作用的理解，并将有利于环境政策的决策。该奖项反映了NSF的法定使命，并已被认为是值得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的支持。