DOI: 10.5194/hess-22-4455-2018
论文题名: Seasonal shifts in export of DOC and nutrients from burned and unburned peatland-rich catchments; Northwest Territories; Canada
作者: Burd K. ; Tank S.E. ; Dion N. ; Quinton W.L. ; Spence C. ; Tanentzap A.J. ; Olefeldt D.
刊名: Hydrology and Earth System Sciences
ISSN: 1027-5606
出版年: 2018
卷: 22, 期: 8 起始页码: 4455
结束页码: 4472
语种: 英语
Scopus关键词: Climate change
; Groundwater
; Nutrients
; Organic carbon
; Permafrost
; Phosphorus
; Runoff
; Stream flow
; Water quality
; Wetlands
; Climatic controls
; Discontinuous permafrost
; Dissolved organic carbon
; Disturbance regime
; DOC concentrations
; Phosphorous concentrations
; Relative contribution
; Total phosphorous
; Catchments
; carbon balance
; catchment
; climate change
; concentration (composition)
; dissolved organic carbon
; disturbance
; food web
; groundwater
; landscape
; nutrient budget
; organic soil
; peatland
; permafrost
; porewater
; precipitation (chemistry)
; runoff
; seasonal variation
; streamflow
; water chemistry
; water quality
; wildfire
; Canada
; Northwest Territories
英文摘要: Boreal peatlands are major catchment sources of dissolved organic carbon (DOC) and nutrients and thus strongly regulate the landscape carbon balance, aquatic food webs, and downstream water quality. Climate change is likely to influence catchment solute yield directly through climatic controls on run-off generation, but also indirectly through altered disturbance regimes. In this study we monitored water chemistry from early spring until fall at the outlets of a 321km2 catchment that burned 3 years prior to the study and a 134km2 undisturbed catchment. Both catchments were located in the discontinuous permafrost zone of boreal western Canada and had ~60% peatland cover. The two catchments had strong similarities in the timing of DOC and nutrient yields, but a few differences were consistent with anticipated effects of wildfire based on peatland porewater analysis. The 4-week spring period, particularly the rising limb of the spring freshet, was crucial for accurate characterization of the seasonal solute yield from both catchments. The spring period was responsible for ~65% of the seasonal DOC and nitrogen and for ~85% of the phosphorous yield. The rising limb of the spring freshet was associated with high phosphorous concentrations and DOC of distinctly high aromaticity and molecular weight. Shifts in stream DOC concentrations and aromaticity outside the early spring period were consistent with shifts in relative streamflow contribution from precipitation-like water in the spring to mineral soil groundwater in the summer, with consistent relative contributions from organic soil porewater. Radiocarbon content (14C) of DOC at the outlets was modern throughout May to September (fraction modern carbon, fM: 0.99-1.05) but likely reflected a mix of aged DOC, e.g. porewater DOC from permafrost (fM: 0.65-0.85) and non-permafrost peatlands (fM: 0.95-1.00), with modern bomb-influenced DOC, e.g. DOC leached from forest litter (fM: 1.05-1.10). The burned catchment had significantly increased total phosphorous (TP) yield and also had greater DOC yield during summer which was characterized by a greater contribution from aged DOC. Overall, however, our results suggest that DOC composition and yield from peatland-rich catchments in the discontinuous permafrost region likely is more sensitive to climate change through impacts on run-off generation rather than through altered fire regimes. © Author(s) 2018. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/163219
Appears in Collections: 气候变化与战略
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作者单位: Burd, K., Department of Renewable Resources, University of Alberta, Edmonton, T6G 2R3, Canada; Tank, S.E., Department of Biological Sciences, University of Alberta, Edmonton, T6G 2E9, Canada; Dion, N., Water Resources Department, Government of Northwest Territories, Yellowknife, X1A 2L9, Canada; Quinton, W.L., Centre for Cold Regions and Water Science, Wilfred Laurier University, Waterloo, N2L 3C5, Canada; Spence, C., National Hydrology Research Centre, Environment and Climate Change Canada, Saskatoon, S7N 3H5, Canada; Tanentzap, A.J., Ecosystems and Global Change Group, Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom; Olefeldt, D., Department of Renewable Resources, University of Alberta, Edmonton, T6G 2R3, Canada
Recommended Citation:
Burd K.,Tank S.E.,Dion N.,et al. Seasonal shifts in export of DOC and nutrients from burned and unburned peatland-rich catchments; Northwest Territories; Canada[J]. Hydrology and Earth System Sciences,2018-01-01,22(8)