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".

本数据集收录了以优势大型水生植物（macrophyte）或水文状态（hydrological state）划分的不同斑块类型的甲烷（CH4）与二氧化碳（CO2）观测数据。CH4与CO2数据涵盖三类测量内容：1. 箱室法地表通量测量；2. 植物箱室叶片通量测量：针对三种通气组织大型水生植物——睡莲（Water Lily）、美洲莲（American Lotus）与香蒲（Cattail），测定单位叶面积的甲烷通量，并同步记录对应叶片的CO2通量；3. 溶解态CO2与CH4的孔隙水浓度：通过原位孔隙水透析剖面（peepers）在土水界面（soil-water interface）以下不同深度的垂直剖面开展原位测量。上述第1、3类观测在2015、2016及2018年生长季（5月至9月）的多数月份按月开展。植物箱室叶片通量测量仅在2018年6、7、8月进行。本数据集还包含2015、2017及2018年的斑块类型分类图，以及该研究区域的相对水位高程图（bathymetry，水深图）。2020年8月23日，我们新增了数据文件"ChamberFluxes_2018_Separated_Diffusive_Ebullitive_Fluxes.xlsx"，其中包含2018年9月在OWC站点开展的箱室法测量相关观测数据。在该批观测中，我们将甲烷通量拆解为扩散组分与冒泡排放组分，所用分析方法详见方法部分第5节“冒泡与扩散分配法（Ebullition and diffusion partitioning）”。