Riparian control on NO3−, DOC, and dissolved Fe concentrations in mountainous streams, northern Japan
Riparian control on NO3−, DOC, and dissolved Fe concentrations in mountainous streams, northern Japan
复制标题
DOI：
10.1007/s10201-008-0251-7
复制
发表时间：
2008-07
期刊：
影响因子：
1.6
通讯作者：
Y. Nakagawa;H. Shibata;F. Satoh;K. Sasa
中科院分区：
文献类型：
--
作者：
Y. Nakagawa;H. Shibata;F. Satoh;K. Sasa
我们评估了（1）河流化学的纵向模式和（2）河岸带对硝酸盐（NO3−），溶解有机碳（DOC）和总溶解铁（Fe）的纵向模式的影响。我们选择了两个小流域;“南部流域”有一个扩展的河岸湿地和“北方流域”有一个狭窄的河岸区。流NO3-浓度下降，从春天到两个流域的出口。在南部流域，流DOC浓度下降，从春季到中游，然后增加到出口。河流Fe浓度在南部流域纵向增加。另一方面，北方流域表现出DOC和Fe浓度没有纵向格局。在这两个流域，而NO3−浓度在土壤和地下水低于那些在流沃茨，DOC和Fe浓度表现出相反的模式。两条河流中NO3−浓度的纵向下降和南部流域河流Fe浓度的增加主要是由于土壤和地下水流入河流。在南部流域，从春季到中游，河流DOC的减少是由于深层地下水具有较低的DOC，而随后增加到周围的土壤和地下水。此外，考虑流溶质流动与土壤和地下水化学提出了其他机制，增加NO3-和去除/稀释DOC和Fe，特别是对于北方流域;河岸带的氧化和还原条件的共存可能会控制纵向浓度变化的流水化学。
We evaluated (1) the longitudinal pattern of stream chemistry and (2) the effects of the riparian zone on this longitudinal pattern for nitrate (NO3−), dissolved organic carbon (DOC), and total dissolved iron (Fe). We selected two small watersheds; the “southern watershed” had an extending riparian wetland and the “northern watershed” had a narrow riparian area. Stream NO3−concentrations decreased from the spring to outlet of both watersheds. In the southern watershed, stream DOC concentration decreased from the spring to midstream and then increased to the outlet. Stream Fe concentration in the southern watershed longitudinally increased. On the other hand, the northern watershed exhibited no longitudinal pattern for DOC and Fe concentrations. In both watersheds, while NO3−concentrations in the soil and ground water were lower than those in the stream waters, DOC and Fe concentrations exhibited the opposite patterns. The longitudinal decreases of NO3−concentrations in both streams and increase of stream Fe in the southern watershed mainly resulted from the inflow of the soil and ground water to the stream. The decrease in stream DOC from the spring to midstream in the southern watershed was due to the deep groundwater having low DOC, while the subsequent increase to the surrounding soil and ground water. Moreover, considerations of stream solute flow with soil and ground water chemistry suggested other mechanisms adding NO3−and removing/diluting DOC and Fe, especially for the northern watershed; coexistence of oxidizing and reducing conditions in the riparian zone might control the longitudinal concentration change in the stream water chemistry.