DOI: 10.5194/hess-19-1209-2015
Scopus记录号: 2-s2.0-84923916986
论文题名: Sediment flow paths and associated organic carbon dynamics across a Mediterranean catchment
作者: Boix-Fayos C ; , Nadeu E ; , Quiñonero J ; M ; , Martínez-Mena M ; , Almagro M ; , De Vente J
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2015
卷: 19, 期: 3 起始页码: 1209
结束页码: 1223
语种: 英语
Scopus关键词: Budget control
; Carbon
; Catchments
; Deposition
; Deposits
; Erosion
; Mineralogy
; Organic carbon
; Particle size
; Reservoirs (water)
; Runoff
; Sediment transport
; Size distribution
; Soils
; Suspended sediments
; Deposited sediments
; Depositional environment
; Depositional setting
; Mediterranean catchment
; Particulate organic carbon
; Selective erosions
; Total Organic Carbon
; Transport distances
; Sediments
; carbon cycle
; catchment
; depositional environment
; erosion rate
; flow pattern
; grain size
; Mediterranean environment
; organic carbon
; sediment transport
; sedimentation
; suspended sediment
; Spain
英文摘要: Terrestrial sedimentation buries large amounts of organic carbon (OC) annually, contributing to the terrestrial carbon sink. The temporal significance of this sink will strongly depend on the attributes of the depositional environment, but also on the characteristics of the OC reaching these sites and its stability upon deposition. The goal of this study was to characterise the OC during transport and stored in the depositional settings of a medium-sized catchment (111 km2) in SE Spain, to better understand how soil erosion and sediment transport processes determine catchment-scale OC redistribution. Total organic carbon (TOC), mineral-associated organic carbon (MOC), particulate organic carbon (POC), total nitrogen (N) and particle size distributions were determined for soils (i), suspended sediments (ii) and sediments stored in a variety of sinks such as sediment wedges behind check dams (iii), channel bars (iv), a small delta in the conjunction of the channel and a reservoir downstream (v), and the reservoir at the outlet of the catchment (vi). The data show that the OC content of sediments was approximately half of that in soils (9.42 ± 9.01 g kg-1 versus 20.45 ± 7.71 g kg-1, respectively) with important variation between sediment deposits. Selectivity of mineral and organic material during transport and deposition increased in a downstream direction. The mineralisation, burial or in situ incorporation of OC in deposited sediments depended on their transport processes and on their post-sedimentary conditions. Upstream sediments (alluvial wedges) showed low OC contents because they were partially mobilised by non-selective erosion processes affecting deeper soil layers and with low selectivity of grain sizes (e.g. gully and bank erosion). We hypothesise that the relatively short transport distances, the effective preservation of OC in microaggregates and the burial of sediments in the alluvial wedges gave rise to low OC mineralisation, as is arguably indicated by C : N ratios similar to those in soils. Deposits in middle stream areas (fluvial bars) were enriched in sand, selected upon deposition and had low OC concentrations. Downstream, sediment transported over longer distances was more selected, poorly microaggregated, and with a prevalence of silt and clay fractions and MOC pool. Overall, the study shows that OC redistribution in the studied catchment is highly complex, and that the results obtained at finer scales cannot be extrapolated at catchment scale. Selectivity of particles during detachment and transport, and protection of OC during transport and deposition are key for the concentration and quality of OC found at different depositional settings. Hence, eco-geomorphological processes during the different phases of the erosion cycle have important consequences for the temporal stability and preservation of the buried OC and in turn for the OC budget. © Author(s) 2015. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/78583
Appears in Collections: 气候变化事实与影响
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作者单位: Soil Erosion and Conservation Research Group, Spanish Research Council, Campus de Espinardo, P.O. Box 164, Murcia, Spain; Department of Geography, University of Murcia, Campus de la Merced, Murcia, Spain
Recommended Citation:
Boix-Fayos C,, Nadeu E,, Quiñonero J,et al. Sediment flow paths and associated organic carbon dynamics across a Mediterranean catchment[J]. Hydrology and Earth System Sciences,2015-01-01,19(3)