DOI: 10.1002/2013GB004686
Scopus记录号: 2-s2.0-84900825622
论文题名: Ecological processes dominate the 13C land disequilibrium in a Rocky Mountain subalpine forest
作者: Bowling D ; R ; , Ballantyne A ; P ; , Miller J ; B ; , Burns S ; P ; , Conway T ; J ; , Menzer O ; , Stephens B ; B ; , Vaughn B ; H
刊名: Global Biogeochemical Cycles
ISSN: 8866236
出版年: 2014
卷: 28, 期: 4 起始页码: 352
结束页码: 370
语种: 英语
英文关键词: biogeochemical cycles
; biosphere/atmosphere interactions
; carbon cycling
; carbon isotope discrimination
; conifer
; forest ecology
Scopus关键词: Biogeochemistry
; Biospherics
; Carbon
; Carbon dioxide
; Forestry
; Fuels
; Isotopes
; Photosynthesis
; Biogeochemical cycle
; Carbon cycling
; Carbon isotope discrimination
; conifer
; Forest ecology
; C (programming language)
; atmospheric modeling
; carbon flux
; coniferous forest
; forest canopy
; human activity
; isotopic fractionation
; photosynthesis
; respiration
; seasonal variation
; subalpine environment
; timescale
; Rocky Mountains
; Coniferophyta
; Embryophyta
英文摘要: Fossil fuel combustion has increased atmospheric CO2 by ≈ 115 μmol mol-1 since 1750 and decreased its carbon isotope composition (δ13C) by 1.7-2‰ (the 13C Suess effect). Because carbon is stored in the terrestrial biosphere for decades and longer, the δ13C of CO2 released by terrestrial ecosystems is expected to differ from the δ13C of CO 2 assimilated by land plants during photosynthesis. This isotopic difference between land-atmosphere respiration (δR) and photosynthetic assimilation (δA) fluxes gives rise to the 13C land disequilibrium (D). Contemporary understanding suggests that over annual and longer time scales, D is determined primarily by the Suess effect, and thus, D is generally positive (δR > δA). A 7 year record of biosphere-atmosphere carbon exchange was used to evaluate the seasonality of δA and δR, and the 13C land disequilibrium, in a subalpine conifer forest. A novel isotopic mixing model was employed to determine the δ13C of net land-atmosphere exchange during day and night and combined with tower-based flux observations to assess δA and δR. The disequilibrium varied seasonally and when flux-weighted was opposite in sign than expected from the Suess effect (D = -0.75 ± 0.21‰ or -0.88 ± 0.10‰ depending on method). Seasonality in D appeared to be driven by photosynthetic discrimination (Δ canopy) responding to environmental factors. Possible explanations for negative D include (1) changes in Δcanopy over decades as CO2 and temperature have risen, and/or (2) post-photosynthetic fractionation processes leading to sequestration of isotopically enriched carbon in long-lived pools like wood and soil. Key Points Carbon isotope contents of photosynthesis and respiration differ Isotope fractionation of land photosynthesis dominates over the 13C Suess effect Biogeochemical C isotope models must include terrestrial ecological processes ©2014. 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/77517
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Biology, University of Utah, Salt Lake City UT, United States; Department of Ecosystem and Conservation Science, University of Montana, Missoula MT, United States; Earth System Research Laboratory, NOAA, Boulder CO, United States; Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder CO, United States; Department of Geography, University of Colorado Boulder, Boulder CO, United States; National Center for Atmospheric Research, Boulder CO, United States; Department of Geography, University of California, Santa Barbara CA, United States; Institute for Arctic and Alpine Research, University of Colorado Boulder, Boulder CO, United States
Recommended Citation:
Bowling D,R,, Ballantyne A,et al. Ecological processes dominate the 13C land disequilibrium in a Rocky Mountain subalpine forest[J]. Global Biogeochemical Cycles,2014-01-01,28(4)