DOI: 10.1002/2014GB005044
Scopus记录号: 2-s2.0-84955202018
论文题名: Pathways and transformations of dissolved methane and dissolved inorganic carbon in Arctic tundra watersheds: Evidence from analysis of stable isotopes
作者: Throckmorton H ; M ; , Heikoop J ; M ; , Newman B ; D ; , Altmann G ; L ; , Conrad M ; S ; , Muss J ; D ; , Perkins G ; B ; , Smith L ; J ; , Torn M ; S ; , Wullschleger S ; D ; , Wilson C ; J
刊名: Global Biogeochemical Cycles
ISSN: 8866236
出版年: 2015
卷: 29, 期: 11 起始页码: 1893
结束页码: 1910
语种: 英语
英文关键词: Arctic
; carbon dioxide
; drainages
; isotopes
; methane
; microbial
Scopus关键词: carbon dioxide
; dissolved gas
; dissolved inorganic carbon
; drainage water
; iron
; methane
; methanogenesis
; microbial activity
; oxidation
; porewater
; spatiotemporal analysis
; stable isotope
; surface water
; transformation
; tundra
; watershed
; Alaska
; Arctic
; Barrow
; United States
英文摘要: Arctic soils contain a large pool of terrestrial C and are of interest due to their potential for releasing significant carbon dioxide (CO2) and methane (CH4) to the atmosphere. Due to substantial landscape heterogeneity, predicting ecosystem-scale CH4 and CO2 production is challenging. This study assessed dissolved inorganic carbon (DIC = Σ (total) dissolved CO2) and CH4 in watershed drainages in Barrow, Alaska as critical convergent zones of regional geochemistry, substrates, and nutrients. In July and September of 2013, surface waters and saturated subsurface pore waters were collected from 17 drainages. Based on simultaneous DIC and CH4 cycling, we synthesized isotopic and geochemical methods to develop a subsurface CH4 and DIC balance by estimating mechanisms of CH4 and DIC production and transport pathways and oxidation of subsurface CH4. We observed a shift from acetoclastic (July) toward hydrogenotropic (September) methanogenesis at sites located toward the end of major freshwater drainages, adjacent to salty estuarine waters, suggesting an interesting landscape-scale effect on CH4 production mechanism. The majority of subsurface CH4 was transported upward by plant-mediated transport and ebullition, predominantly bypassing the potential for CH4 oxidation. Thus, surprisingly, CH4 oxidation only consumed approximately 2.51 ± 0.82% (July) and 0.79 ± 0.79% (September) of CH4 produced at the frost table, contributing to <0.1% of DIC production. DIC was primarily produced from respiration, with iron and organic matter serving as likely e- acceptors. This work highlights the importance of spatial and temporal variability of CH4 production at the watershed scale and suggests broad scale investigations are required to build better regional or pan-Arctic representations of CH4 and CO2 production. ©2015. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/77912
Appears in Collections: 气候变化事实与影响
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作者单位: Los Alamos National Laboratory, Earth and Environmental Sciences Division, Los Alamos, NM, United States; Lawrence Berkeley National Laboratory, Earth Sciences Division, Berkeley, CA, United States; Oak Ridge National Laboratory, Environmental Sciences Division, Oak Ridge, TN, United States
Recommended Citation:
Throckmorton H,M,, Heikoop J,et al. Pathways and transformations of dissolved methane and dissolved inorganic carbon in Arctic tundra watersheds: Evidence from analysis of stable isotopes[J]. Global Biogeochemical Cycles,2015-01-01,29(11)