EAR-PF: Methane Dynamics in Tidal Salt Marshes: Production and Fate

玛格丽特·卡波奇博士获得了NSF EAR博士后奖学金，在阿曼达·斯皮瓦克博士的指导下，她将在佐治亚大学从事研究并继续深造。卡波西博士将进行实地实验，以更好地了解盐沼土壤中的甲烷动态。潮汐盐沼，以及红树林和海草床，在其土壤中储存了大量的碳。沼泽还可以通过几种途径释放碳，包括从土壤向大气排放甲烷。由于盐沼在通过碳储存减少气候变化方面发挥着重要作用，因此了解盐沼如何、何时以及为什么释放甲烷是很重要的，甲烷是一种促成气候变化的气体。因此，卡波奇博士的研究旨在更好地了解盐沼土壤产生、消耗和释放甲烷的方式。这些数据将帮助科学家更好地模拟盐沼的碳循环，并为更好地恢复和管理盐沼的碳储存效益提供信息。卡波西博士还将邀请来自服务不足和代表性不足社区的教师和本科生参与她的研究，包括在沼泽收集实际数据的机会。人们认为，在潮汐盐沼中，甲烷排放量很低，甚至根本不存在，因为土壤中的硫减剂比乙酰基碎裂和水基因营养甲烷生成更具竞争力。然而，研究人员在沼泽中发现了高甲烷排放量，以及另一种甲烷生成途径，甲烷营养甲烷生成作用，它使用非竞争性底物来产生甲烷。然而，在盐沼中，甲烷排放量是高度可变的，很难预测。因此，要解决甲烷排放的异质性，就必须更仔细地研究在各种情况下甲烷是如何产生、消费和运输的，并将这些过程与活跃的微生物群落联系起来。该项目将综合使用多种技术，包括中尺度研究、同位素示踪、定性主要同位素探测和实地调查，以评估甲烷动态在时间(即潮汐、季节)和空间(即从微米到小区尺度、从土壤表面到深度)尺度上的变化。该项目旨在通过提供有关甲烷动力学的机械信息来促进盐沼碳循环的科学知识，这些信息可用于跨地点应用，并可用于在模型运行中放大甲烷通量，以及提供数据以支持自然资源管理者保护和恢复盐沼。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Dr. Margaret Capooci has been awarded an NSF EAR Postdoctoral Fellowship to pursue research and further her education at the University of Georgia under the mentorship of Dr. Amanda Spivak. Dr. Capooci will conduct field experiments to better understand methane dynamics in salt marsh soils. Tidal salt marshes, along with mangrove forests and seagrass beds, store large amounts of carbon within their soils. Marshes can also release carbon through several pathways, including methane emission from the soil to the atmosphere. Since salt marshes play an important role in reducing climate change via carbon storage, it is important to understand how, when, and why salt marshes release methane, a gas that contributes to climate change. Therefore, Dr. Capooci’s research aims to better understand the ways in which methane is produced, consumed, and released from salt marsh soils. These data will help scientists better model salt marsh carbon cycling, as well as provide information to better restore and manage salt marshes for their carbon storage benefits. Dr. Capooci will also involve teachers and undergraduate students from underserved and underrepresented communities in her research, including opportunities for hands-on data collection in the marsh.Methane emissions were thought to be low-to-non-existent in tidal salt marshes due to acetoclastic and hydrogenotrophic methanogenesis being outcompeted by sulfur reducers in the soil. However, researchers have found high methane emissions in marshes, as well as an alternative methanogenesis pathway, methanotrophic methanogensis, that uses non-competitive substrates to produce methane. However, methane emissions are highly variable and difficult to predict in salt marshes. Therefore, resolving the heterogeneity regarding CH4 emissions necessitates a closer look at how methane is produced, consumed, and transported under a variety of scenarios, as well as linking these processes to active microbial communities. A combination of techniques will be used in this project, including mesocosm studies, isotopic tracers, qualitative staple isotope probing, and field surveys to assess how methane dynamics change over temporal (i.e., tidal, seasonal) and spatial (i.e., micrometer to plot scale, depth from soil surface) scales. This project aims to advance scientific knowledge of salt marsh carbon cycling by providing mechanistic information regarding methane dynamics that can be applied across sites and be used to up-scale methane fluxes in model runs, as well as provide data to support natural resource managers in the conservation and restoration of salt marshes.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.