Trace gas data for Dead Run, Baltimore County, MD, USA

This resource includes trace gas data collected at three locations in the Dead Run stream network in Woodlawn, Baltimore County, MD. Dissolved gas species include CH4, N2O, CO2, and N2:Ar. Stream grab samples and ambient air samples are collected biweekly and analyzed for trace gas concentrations at the Cary Institute of Ecosystem Studies. Sampling stations are co-located with USGS stream gaging stations 01589312 (DR5), 01589315 (DR4), and 01589330 (DRKR). Protocols for sampling and analysis follow those of the National Ecological Observatory Network (NEON) and Cary Institute of Ecosystem Studies.

Dissolved gas measurements of streams coupled with groundwater can provide information on integrated source/sink dynamics within the urban critical zone. CO2 concentrations are driven by weathering reactions and biological activity. Nitrous oxide (N2O) is an index of nitrogen enrichment in the landscape. Methane (CH4) and dissolved nitrogen:argon (N2:Ar) indicate presence of anaerobic conditions and nitrogen sinks. Gas data can help determine the interplay between nitrogen inputs and processing in the urban critical zone. For example, high N2O (and nitrate) can provide evidence of a shift from a source-controlled to transport-controlled system. Low N2O (and low nitrate) along with high CH4 and high dissolved N2:Ar also can provide evidence of a similar shift but would suggest the presence of significant anaerobic sinks with implications about water pathways through the urban critical zone.

本资源包括在马里兰州巴尔的摩县伍德劳恩的Dead Run流域网络中的三个地点收集的痕量气体数据。溶解气体种类包括甲烷（CH4）、氧化亚氮（N2O）、二氧化碳（CO2）以及氮气与氩气的混合物（N2:Ar）。河流抓取样本和大气样本每两周收集一次，并在卡里生态系统研究学院进行分析，以确定痕量气体的浓度。采样站位于美国地质调查局河流测量站01589312（DR5）、01589315（DR4）和01589330（DRKR）附近。采样和分析协议遵循国家生态系统观测网络（NEON）和卡里生态系统研究学院的规定。河流中溶解气体测量与地下水的结合，能够提供关于城市关键区内部源/汇综合动态的信息。二氧化碳浓度受风化反应和生物活动驱动。氧化亚氮（N2O）是景观中氮富集的指标。甲烷（CH4）和溶解的氮气与氩气（N2:Ar）的存在指示了厌氧条件和氮汇。气体数据有助于确定城市关键区内氮输入与处理之间的相互作用。例如，高浓度的N2O（以及硝酸盐）可能表明系统从源控制转向传输控制。低浓度的N2O（以及低硝酸盐）伴随着高CH4和高溶解的N2:Ar也可以提供类似的转变证据，但会表明存在重要的厌氧汇，这对城市关键区内的水路径有重要意义。