Methane and CO2 chamber fluxes and porewater concentrations US-OWC Ameriflux wetland site, 2015-2018

The data measurements of CH4 and CO2 at different patch types (classified by dominant macrophyte vegetation or hydrological state). CH4 and CO2 data include 3 types of measurements: 1) Surface flux measurements from chamber measurements. 2) Leaf flux measurements from plant chambers, providing the rate per leaf area of methane flow through three species of macropyte aerenchemous plants (Water Lily, American Lotus, and Cattail) with the corresponding flux of CO2 at the same leaves. 3) Pore water concentrations of dissolved CO2 and CH4 concentrations. These are measured along vertical profiles at varying depths from the soil-water interface using in-situ porewater dialysis profiles (peepers). Observations of 1 and 3 are available monthly for most months of the growing season (May-September) of 2015, 2016 and 2018. Leaf flux measurements (plant chambers) are available only in June, July and August of 2018. We also included the patch type classification maps during 2015, 2017 and 2018 the relative water elevation map (bathymetry) for the site. In 8/23/2020 we added the data file ChamberFluxes_2018_Separated_Diffusive_Ebullitive_Fluxes.xlsx with observation related to chamber measurements in OWC during September 2018. In these observations, we partitioned the methane flux to its diffusive and ebullitive components, using an analysis approach we describe in section 5 of the methods "Ebullition and diffusion partitioning".

本数据集涵盖基于不同斑块类型分类的甲烷（CH4）与二氧化碳（CO2）观测数据，其中斑块类型以优势大型水生植物或水文状态进行划分。数据集包含三类测量数据：1）箱法地表通量测量：采用静态箱法开展地表通量观测；2）植物箱法叶片通量测量：针对三种具有通气组织的大型水生植物——睡莲（Water Lily）、美洲莲（American Lotus）与香蒲（Cattail），获取单位叶面积的甲烷通量，并同步记录对应叶片的二氧化碳通量；3）孔隙水溶解态CO2与CH4浓度：采用原位孔隙水透析剖面采样器（peepers），在土-水界面以下不同深度的垂直剖面开展测量。上述第1类与第3类观测在2015、2016及2018年的生长季（5月至9月）的多数月份按月开展。植物箱法叶片通量测量仅在2018年6、7、8月进行。本数据集同时包含2015、2017及2018年的斑块类型分类图，以及研究样地的相对水位高程图（水深图，bathymetry）。2020年8月23日，新增数据集文件ChamberFluxes_2018_Separated_Diffusive_Ebullitive_Fluxes.xlsx，其中包含2018年9月于OWC样地开展的箱法通量观测数据。该批观测通过“气泡逸出与扩散分配”方法（详见方法部分第5节）将甲烷通量划分为扩散组分与气泡逸出组分。