当前位置: X-MOL 学术J. Geophys. Res. Biogeosci. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Temporal Patterns of Methane Emissions From Two Streams With Different Riparian Connectivity
Journal of Geophysical Research: Biogeosciences ( IF 3.7 ) Pub Date : 2021-07-26 , DOI: 10.1029/2020jg006104
Peifang Leng 1, 2 , Norbert Kamjunke 3 , Fadong Li 2, 4 , Matthias Koschorreck 1
Affiliation  

Streams are regionally important sources of CH4 to the atmosphere, but the temporal variability in and control on CH4 concentrations and emissions are not well understood. Especially, lack of long-term data hampers our ability to predict CH4 emissions from streams. Here, we present a 7-year data set of biweekly CH4 concentration and underlying potential drivers from two adjacent small German streams with contrasting riparian area characteristics. Over the 7-year study period, mean CH4 concentration and emissions were 0.20 and 0.07 μmol L−1 and 2.01 and 0.84 mmol m−2 d−1 for the two streams, respectively. Our findings suggest that the combination of seasonality and topography ultimately shaped the considerable temporal variations of CH4. CH4 oxidation and production in the streams were probably of minor importance. Instead, fluctuations in CH4 concentrations likely reflected a temporal pattern of CH4 input from soils of the riparian zone with larger CH4 variations in the stream with more riparian lands. Structural equation modeling revealed dissolved organic carbon and nitrate as important predictors of CH4 concentration. However, we did not identify predictors of the considerable short-term variability, nor the explicit pathways of CH4 delivery to streams. The discrepancy of the CH4 flux between streams was likely triggered by different connectivities to riparian soils with higher CH4 emissions in the hydrologically more connected stream. Interannual comparison showed that changing hydrologic conditions, rather than warming, may impact future CH4 emissions from temperate streams. We predict that higher CH4 emissions occur in wetter years in streams with close connectivity to riparian soils.

中文翻译:

具有不同河岸连通性的两条河流的甲烷排放时间模式

河流是大气中 CH 4 的区域性重要来源,但对 CH 4浓度和排放的时间变化和控制尚不清楚。特别是,缺乏长期数据阻碍了我们预测来自河流的CH 4排放的能力。在这里,我们展示了一个为期 7 年的双周 CH 4浓度数据集,以及来自两个相邻的德国小溪流的潜在驱动因素,具有对比的河岸地区特征。在 7 年的研究期间,平均 CH 4浓度和排放量分别为 0.20 和 0.07 μmol L -1以及 2.01 和 0.84 mmol m -2  d -1分别为两个流。我们的研究结果表明,季节性和地形的结合最终形成了 CH 4相当大的时间变化。流中的CH 4氧化和生成可能不太重要。相反,CH 4浓度的波动可能反映了来自河岸带土壤的CH 4输入的时间模式,在河流中具有更多河岸土地的CH 4变化更大。结构方程模型显示溶解的有机碳和硝酸盐是 CH 4浓度的重要预测因子。然而,我们没有确定相当大的短期可变性的预测因子,也没有确定 CH 的明确途径4传送到流。河流之间CH 4通量的差异可能是由与河岸土壤的不同连通性触发的,河岸土壤在水文上更连通的河流中具有更高的 CH 4排放。年际比较表明,变化的水文条件,而不是变暖,可能会影响温带河流未来的 CH 4排放。我们预测较高的 CH 4排放发生在与河岸土壤紧密相连的河流中的潮湿年份。
更新日期:2021-08-12
down
wechat
bug