The Magnitude and Drivers of Sediment Methane Production in Streams across Europe

河流系统（溪流和河流）最近被认为是全球大气CH 4的重要来源。因此，许多研究测量在沉积物-水界面或在水-空气界面的气态CH 4通量。然而，结合各种途径的潜在的气态甲烷通量到大气中的随机性质的沸腾事件导致大的不确定性，平均通量估计。评估甲烷的潜在生产和氧化率，即侧重于控制甲烷生产和损失的过程，与通量测量相比，可能是一种替代办法。然而，这些过程的驱动因素及其在流中的空间变异性尚未完全理解。这个拟议项目的总体目标是，根据我们的知识，第一次，估计空间变异的潜在甲烷生产和氧化速率（PMP和PMO）和它们的驱动因素在两个空间尺度上的流沉积物：流到达尺度和大陆尺度。为了实现这一目标，拟议的项目采用了目前正在进行的欧洲范围内的项目：EuroRun（评估欧洲流动沃茨的二氧化碳通量）的框架。EuroRun由16支队伍组成，分布在11个欧洲国家的不同地方。每个EuroRun团队将在欧洲的一条河流中采集沉积物样本，并将其发送到科布伦茨-朗道大学，该项目的主要研究人员将测量PMP和PMO以及相应样本的沉积物特征（有机质质量，如沉积物碳氮含量，粒度分布）。拟议项目的成功执行将大大加强目前对河流中甲烷生产的了解。此外，在大陆尺度上的PMP和PMO的潜在驱动因素的调查可能会提供重要的参数，可以在一个基于过程的模型，预测CH 4生产，从而在流生态系统的排放动态。

Fluvial systems (streams and rivers) have been recently recognized as a globally significant source of atmospheric CH4. Hence, many studies measure gaseous CH4 fluxes at the sediment-water interface or at the water-air interface. However, the combination of various pathways of potential gaseous methane fluxes to the atmosphere with the stochastic nature of ebullition events lead to large uncertainties in averaged flux estimates. Assessing the potential production and oxidation rates of methane, i.e. focusing on the processes that control CH4 production and loss, may represent an alternative approach compared to flux measurements. However, the driving factors of these processes and their spatial variability in streams are not yet fully understood. The overall goal of this proposed project is, according to our knowledge for the first time, to estimate the spatial variability of potential methane production and oxidation rates (PMP and PMO) and their driving factors in stream sediments at two spatial scales: the stream reach scale and the continental scale. In order to archive this goal, the proposed project uses the framework of a currently ongoing European wide project: EuroRun (Assessing CO2 fluxes from European running waters). EuroRun consists of 16 teams all located at different places in 11 European countries. Each EuroRun team will samples sediment samples in one stream across Europe and send them to the University of Koblenz-Landau, where the principle investigator of the project will measure PMP and PMO as well as sediment characteristics of the respective samples (organic matter quality as sediment carbon to nitrogen content, grain size distribution). A successful execution of the proposed project will strongly enhance the current understanding of CH4 production in streams. Furthermore, the investigation of potential drivers of PMP and PMO at continental scale may provide important parameters which can be implemented in a process-based model, predicting CH4 production and consequently emission dynamics in stream ecosystems.