DOI: 10.5194/cp-8-1177-2012
Scopus记录号: 2-s2.0-84872359719
论文题名: Enrichment in 13C of atmospheric CH4 during the Younger Dryas termination
作者: Melton J.R. ; Schaefer H. ; Whiticar M.J.
刊名: Climate of the Past
ISSN: 18149324
出版年: 2012
卷: 8, 期: 4 起始页码: 1177
结束页码: 1197
语种: 英语
Scopus关键词: biomass burning
; carbon isotope
; concentration (composition)
; enrichment
; gas hydrate
; ice core
; methane
; mixing ratio
; paleoatmosphere
; paleoclimate
; thermokarst
; warming
; wetland
; Younger Dryas
; Antarctica
; Arctic
; Greenland
; Pakitsoq
英文摘要: The abrupt warming across the Younger Dryas termination (∼11 600 yr before present) was marked by a large increase in the global atmospheric methane mixing ratio. The debate over sources responsible for the rise in methane centers on the roles of global wetlands, marine gas hydrates, and thermokarst lakes. We present a new, higher-precision methane stable carbon isotope ratio (δ13CH4) dataset from ice sampled at Päkitsoq, Greenland that shows distinct 13C-enrichment associated with this rise. We investigate the validity of this finding in face of known anomalous methane concentrations that occur at Päkitsoq. Comparison with previously published datasets to determine the robustness of our results indicates a similar trend in ice from both an Antarctic ice core and previously published Päkitsoq data measured using four different extraction and analytical techniques. The δ13CH4 trend suggests that 13C-enriched CH4 sources played an important role in the concentration increase. In a first attempt at quantifying the various contributions from our data, we apply a methane triple mass balance of stable carbon and hydrogen isotope ratios and radiocarbon. The mass balance results suggest biomass burning (42-66% of total methane flux increase) and thermokarst lakes (27-59%) as the dominant contributing sources. Given the high uncertainty and low temporal resolution of the 14CH4 dataset used in the triple mass balance, we also performed a mass balance test using just δ13C and δD. These results further support biomass burning as a dominant source, but do not allow distinguishing of thermokarst lake contributions from boreal wetlands, aerobic plant methane, or termites. Our results in both mass balance tests do not suggest as large a role for tropical wetlands or marine gas hydrates as commonly proposed. © 2012 Author(s). 资助项目: Canadian Foundation for Climate and Atmospheric Sciences Canada
; NSF, National Science Foundation
; NSF, National Science Foundation
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/49535
Appears in Collections: 气候变化与战略
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Recommended Citation:
Melton J.R.,Schaefer H.,Whiticar M.J.. Enrichment in 13C of atmospheric CH4 during the Younger Dryas termination[J]. Climate of the Past,2012-01-01,8(4)