Link between DOC in near surface peat and stream water in an upland catchment.
Link between DOC in near surface peat and stream water in an upland catchment.
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DOI：
10.1016/j.scitotenv.2007.11.002
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发表时间：
2008-10
期刊：
影响因子：
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通讯作者：
Joanna M. Clark;S. Lane;P. Chapman;J. Adamson
中科院分区：
文献类型：
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作者：
Joanna M. Clark;S. Lane;P. Chapman;J. Adamson
由于土壤剖面和水文的差异，泥炭土壤中溶解有机碳（DOC）的水文输运可能与有机矿物土壤对流量变化的反应不同。在排水良好的有机无机土壤中，低流量是通过较低的矿物层，其中DOC被吸收，高流量是通过较高的有机层，其中DOC被产生。在流排水有机无机土壤DOC浓度通常增加流量。在饱和的泥炭土中，高流量和低流量都是通过有机层产生DOC。因此，DOC在流排水泥炭可能不会增加响应流量的变化，因为没有切换之间的矿物和有机层的流动路径。为了验证这一点，我们进行了高分辨率的监测研究，土壤和溪流水在高地泥炭集水区在北方英格兰。我们的数据显示，-1和-5 cm深度的DOC浓度与溪流水之间有很强的正相关性，而-20至-50 cm深度的DOC浓度与溪流水之间的相关性较弱。虽然近地表的有机物质似乎是关键来源的流水DOC在泥炭和有机-矿物土壤，我们观察到流和DOC浓度之间的负相关性，而不是一个正相关的DOC从有机层释放在低流量和高流量被稀释的降雨。泥炭和有机-矿物土壤之间DOC传输过程的差异对我们理解DOC出口的长期变化有不同的影响。虽然降雨量的增加可能会导致DOC通量从泥炭由于水体积的增加，它可能会导致浓度下降。这种反应是相反的有机无机土壤，增加降雨量可能会导致增加通量和浓度DOC出口的预期变化。
Hydrologic transport of dissolved organic carbon (DOC) from peat soils may differ to organo-mineral soils in how they responded to changes in flow, because of differences in soil profile and hydrology. In well-drained organo-mineral soils, low flow is through the lower mineral layer where DOC is absorbed and high flow is through the upper organic layer where DOC is produced. DOC concentrations in streams draining organo-mineral soils typically increase with flow. In saturated peat soils, both high and low flows are through an organic layer where DOC is produced. Therefore, DOC in stream water draining peat may not increase in response to changes in flow as there is no switch in flow path between a mineral and organic layer. To verify this, we conducted a high-resolution monitoring study of soil and stream water at an upland peat catchment in northern England. Our data showed a strong positive correlation between DOC concentrations at −1 and −5 cm depth and stream water, and weaker correlations between concentrations at −20 to −50 cm depth and stream water. Although near surface organic material appears to be the key source of stream water DOC in both peat and organo-mineral soils, we observed a negative correlation between stream flow and DOC concentrations instead of a positive correlation as DOC released from organic layers during low and high flow was diluted by rainfall. The differences in DOC transport processes between peat and organo-mineral soils have different implications for our understanding of long-term changes in DOC exports. While increased rainfall may cause an increase in DOC flux from peat due to an increase in water volume, it may cause a decrease in concentrations. This response is contrary to expected changes in DOC exports from organo-mineral soils, where increase rainfall is likely to result in an increase in flux and concentration.