Effects of instream processes, discharge, and land cover on nitrogen export from southern Appalachian Mountain catchments
Effects of instream processes, discharge, and land cover on nitrogen export from southern Appalachian Mountain catchments
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河流内过程、排放和土地覆盖对阿巴拉契亚山脉南部流域氮输出的影响
DOI：
10.1002/hyp.13325
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发表时间：
2018
影响因子：
3.2
通讯作者：
Jackson, C. Rhett
中科院分区：
文献类型：
--
作者：
Webster, Jackson R.;Stewart, Rebecca M.;Knoepp, Jennifer D.;Jackson, C. Rhett
小干扰流域通常有低溶解无机氮（DIN）输出，但干扰和人为输入导致DIN浓度升高和输出和下游生态系统的富营养化。我们研究了美国阿巴拉契亚山脉南部的溪流，该地区以阔叶落叶林为主，但也有山谷农业和住宅开发。我们每周从9个小集水区和3个河流站点收集抓斗样本和风暴样本。大部分流量发生在基流，基流指数范围从69%到95%。我们确定了基流DIN浓度的三个季节性模式。溪流在大多数森林流域有低DIN双峰，夏季高峰大于冬季高峰。农业和开发较多的溪流也有双峰;然而，冬季的峰值最高。在河流排水集水区与更多的住宅开发，DIN浓度有一个单一的高峰，最大的在冬季和夏季最低。估计DIN出口的三种方法产生了一致的结果。年DIN输出量范围从干扰较少的集水区的不到200 g ha− 1 year − 1到森林面积最小的集水区的超过2，000 g ha− 1 year − 1不等。土地覆被是一个很强的DIN浓度的预测，但不太重要的DIN输出预测。两个森林参考集水区出现供应有限，最住宅集水区出现运输有限，和其他集水区的出口显着相关的排放。在所有流中，基流DIN输出超过了风暴流输出。流域之间的形态和气候变化造成了土地覆盖无法解释的复杂性。然而，回归模型开发的土地覆盖数据从小流域合理预测浓度和出口接收河流。我们的研究结果说明了在一个地区与马赛克的气候，地质，地形，土壤，植被，过去和现在的土地利用的DIN出口所涉及的机制的复杂性。
Catchments with minimal disturbance usually have low dissolved inorganic nitrogen (DIN) export, but disturbances and anthropogenic inputs result in elevated DIN concentration and export and eutrophication of downstream ecosystems. We studied streams in the southern Appalachian Mountains, USA, an area dominated by hardwood deciduous forest but with areas of valley agriculture and increasing residential development. We collected weekly grab samples and storm samples from nine small catchments and three river sites. Most discharge occurred at baseflow, with baseflow indices ranging from 69% to 95%. We identified three seasonal patterns of baseflow DIN concentration. Streams in mostly forested catchments had low DIN with bimodal peaks, and summer peaks were greater than winter peaks. Streams with more agriculture and development also had bimodal peaks; however, winter peaks were the highest. In streams draining catchments with more residential development, DIN concentration had a single peak, greatest in winter and lowest in summer. Three methods for estimating DIN export produced consistent results. Annual DIN export ranged from less than 200 g ha−1year−1for the less disturbed catchments to over 2,000 g ha−1year−1in the catchments with the least forest area. Land cover was a strong predictor of DIN concentration but less significant for predicting DIN export. The two forested reference catchments appeared supply limited, the most residential catchment appeared transport limited, and export for the other catchments was significantly related to discharge. In all streams, baseflow DIN export exceeded stormflow export. Morphological and climatological variation among watersheds created complexities unexplainable by land cover. Nevertheless, regression models developed using land cover data from the small catchments reasonably predicted concentration and export for receiving rivers. Our results illustrate the complexity of mechanisms involved in DIN export in a region with a mosaic of climate, geology, topography, soils, vegetation, and past and present land use.
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影响因子：
5.4
作者：
Laurence Lin;J. Webster;T. Hwang;L. Band
通讯作者：
Laurence Lin;J. Webster;T. Hwang;L. Band
影响因子：
4
作者：
Buffam, I;Galloway, JN;McGlathery, KJ
通讯作者：
McGlathery, KJ
影响因子：
2.4
作者：
L. Owens;W. Edwards;R. W. Keuren
通讯作者：
R. W. Keuren
蓝岭东部库维塔水文实验室的基岩地质和区域地质环境
影响因子：
5.4
作者：
R. Hatcher
通讯作者：
R. Hatcher
溪流营养物和溶解有机碳浓度的季节性模式：分离流域流动路径和河内效应
影响因子：
5.4
作者：
P. Mulholland;W. Hill
通讯作者：
W. Hill