Linking denitrification with ecosystem respiration in mountain streams
Linking denitrification with ecosystem respiration in mountain streams
复制标题
将反硝化与山间溪流生态系统呼吸联系起来
DOI：
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发表时间：
2019
影响因子：
7.8
通讯作者：
R. Hall
中科院分区：
文献类型：
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作者：
H. Madinger;R. Hall
河流会分解一部分硝酸盐（NO3−）负荷，但很难使用微观或范围尺度测量进行估计，因为这些测量需要特定的地球化学和水文条件。测量范围尺度的氧（O2）呼吸通量比氮（N2）通量更容易，因此我们将N2生产的反硝化作用的微观估计与有氧呼吸的估计配对。13股物流的ΔN2：-ΔO2摩尔比中位数为0.011（95%可信区间0.0002-0.027摩尔：摩尔）。然后，我们测量了11个流的昼夜O2浓度，并转换为生态系统呼吸（ER）使用多日氧模型。考虑到到达尺度ER为−160 mmol O2 m−2 d−1，我们的河流中估计的中值反硝化作用为1.5 mmol N2 m−2 d−1（可信区间（CI）：0.18-4.21）。我们估计反硝化作用占总NO3−吸收量的19%（CI：0-51%）。溪流中的ΔN2：-ΔO2低于河口和海洋生态系统。尽管有多种误差来源，但这种方法估计了达到规模的反硝化作用和NO3−浓度的变化。
Rivers denitrify a portion of their nitrate ( NO3− ) load, but estimates are difficult using microcosm or reach‐scale measurements that require specific biogeochemical and hydrologic conditions. Measuring reach‐scale oxygen (O2) respiration fluxes is easier than nitrogen (N2) fluxes, thus we paired microcosm estimates of denitrification by N2 production with estimates of aerobic respiration. The median molar ratio of ΔN2:−ΔO2 from 13 streams was 0.011 (95% credible interval 0.0002–0.027 mol:mol). We then measured diel O2 concentrations from 11 streams and converted to ecosystem respiration (ER) using a multiday oxygen model. Given reach‐scale ER of −160 mmol O2 m−2 d−1, the estimated median denitrification was 1.5 mmol N2 m−2 d−1 (credible interval (CI): 0.18–4.21) across our streams. Our estimates of denitrification constituted 19% of gross NO3− uptake (CI: 0–51%). In streams, ΔN2:−ΔO2 was lower than in estuarine and marine ecosystems. Despite multiple sources of error, this approach estimates reach‐scale denitrification and variation with NO3− concentrations.