气候变化领域集成服务门户(CCPortal): Are dissolved organic carbon concentrations in riparian groundwater linked to hydrological pathways in the boreal forest?

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DOI	10.5194/hess-24-1709-2020
	Are dissolved organic carbon concentrations in riparian groundwater linked to hydrological pathways in the boreal forest?
	Ploum S.W.; Laudon H.; Peralta-Tapia A.; Kuglerová L.
发表日期	2020
ISSN	1027-5606
起始页码	1709
结束页码	1720
卷号	24 期号:4
英文摘要	The riparian zone (RZ), or near-stream area, plays a fundamental role in the biogeochemistry of headwaters. Here, wet, carbon-rich soils can change groundwater chemistry before it enters the stream. In the boreal forest, the RZ plays an especially important role in the export of dissolved organic carbon (DOC) to streams. However, the RZ is not uniform, and spatial variability of riparian groundwater hydrology and chemistry can be large. Terrestrial topographic depressions create hydrological pathways towards focal points in the RZ, which we refer to as "discrete riparian inflow points" (DRIPs). Combining the chemical function of the RZ and the convergence of hydrological pathways, we hypothesize that DRIPs play a disproportionally large role in conveying DOC to small streams. Earlier work has demonstrated that runoff from DRIPs can make up the majority of riparian flow contributions to streams, but it is currently unknown how their groundwater chemistry differs from the rest of the RZ. Therefore, we ask the following question: are DOC concentrations in riparian groundwater linked to hydrological pathways in the boreal forest? To answer this question, we sampled riparian groundwater during six campaigns across three boreal headwater streams in Sweden. The groundwater wells were distributed into 10 DRIP and non-DRIP pairs (60 wells), following transects from the upland (20 m lateral distance from the stream bank) to the near-stream area ( <5 m lateral distance from the stream bank). The variability in DOC, pH, and electrical conductivity (EC) was analyzed using linear mixed-effects models (LMMs). We explained the variability using three factors: distance from the stream, seasonality, and DRIP/nonDRIP. Our results showed that DRIPs provided DOC-rich water (34 mg L-1) with relatively low EC (36 μS cm-1). The "non-DRIP" riparian water had 40 % lower DOC concentrations (20 mg L-1) and a 45 % higher EC (52 μS cm-1) on average. Moreover, groundwater chemistry from DRIPs was spatially and temporally relatively homogeneous. In contrast, non-DRIP water transformed distinctly in the last 25 m towards the stream, and the chemical variability was also larger between seasons. We concluded that hydrological pathways and spatial variability in riparian groundwater DOC concentrations are linked, and that DRIPs can be seen as important control points in the boreal landscape. Characterizing DRIPs in headwater catchments can be useful for upscaling carbon inputs in boreal stream ecosystems and for delineating hydrologically adapted buffers for forest management practices. © 2020 Author(s).
语种	英语
scopus关键词	Catchments; Ecosystems; Forestry; Groundwater; Hydrochemistry; Organic carbon; Runoff; Stream flow; Chemical variability; Dissolved organic carbon; Electrical conductivity; Forest management practices; Groundwater chemistry; Linear mixed-effects model; Riparian groundwater; Spatial variability; Rivers; biogeochemistry; boreal forest; concentration (composition); dissolved organic carbon; hydrogeochemistry; hydrology; inflow; riparian zone; topography; well water
来源期刊	Hydrology and Earth System Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/159447
作者单位	Ploum, S.W., Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, 901 86, Umeä, Sweden; Laudon, H., Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, 901 86, Umeä, Sweden; Peralta-Tapia, A., Department of Ecology and Environmental Sciences, Umeä University, Umeä, 901g 87, Sweden; Kuglerová, L., Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, 901 86, Umeä, Sweden
推荐引用方式 GB/T 7714	Ploum S.W.,Laudon H.,Peralta-Tapia A.,et al. Are dissolved organic carbon concentrations in riparian groundwater linked to hydrological pathways in the boreal forest?[J],2020,24(4).
APA	Ploum S.W.,Laudon H.,Peralta-Tapia A.,&Kuglerová L..(2020).Are dissolved organic carbon concentrations in riparian groundwater linked to hydrological pathways in the boreal forest?.Hydrology and Earth System Sciences,24(4).
MLA	Ploum S.W.,et al."Are dissolved organic carbon concentrations in riparian groundwater linked to hydrological pathways in the boreal forest?".Hydrology and Earth System Sciences 24.4(2020).