DOI: 10.1111/gcb.14889
论文题名: Land-use controls on carbon biogeochemistry in lowland streams of the Congo Basin
作者: Drake T.W. ; Podgorski D.C. ; Dinga B. ; Chanton J.P. ; Six J. ; Spencer R.G.M.
刊名: Global Change Biology
ISSN: 13541013
出版年: 2020
卷: 26, 期: 3 语种: 英语
英文关键词: African lowland forest
; carbon biogeochemistry
; carbon cycle
; Congo Basin
; dissolved inorganic carbon
; dissolved organic matter
; land-use change
; tropical deforestation
Scopus关键词: biogeochemistry
; carbon cycle
; deforestation
; dissolved inorganic carbon
; dissolved organic matter
; land use change
; lowland environment
; stream
; tropical forest
; Congo Basin
; Tracheophyta
英文摘要: The flux and composition of carbon (C) from land to rivers represents a critical component of the global C cycle as well as a powerful integrator of landscape-level processes. In the Congo Basin, an expansive network of streams and rivers transport and cycle terrigenous C sourced from the largest swathe of pristine tropical forest on Earth. Increasing rates of deforestation and conversion to agriculture in the Basin are altering the current regime of terrestrial-to-aquatic biogeochemical cycling of C. To investigate the role of deforestation on dissolved organic and inorganic C (DOC and DIC, respectively) biogeochemistry in the Congo Basin, six lowland streams that drain catchments of varying forest proportion (12%–77%) were sampled monthly for 1 year. Annual mean concentrations of DOC exhibited an asymptotic response to forest loss, while DIC concentrations increased continuously with forest loss. The isotopic signature of DIC became significantly more enriched with deforestation, indicating a shift in source and processes controlling DIC production. The composition of dissolved organic matter (DOM), as revealed by ultra-high-resolution mass spectrometry, indicated that deforested catchments export relatively more aliphatic and heteroatomic DOM sourced from microbial biomass in soils. The DOM compositional results imply that DOM from the deforested sites is more biolabile than DOM from the forest, consistent with the corresponding elevated stream CO2 concentrations. In short, forest loss results in significant and comprehensive shifts in the C biogeochemistry of the associated streams. It is apparent that land-use conversion has the potential to dramatically affect the C cycle in the Congo Basin by reducing the downstream flux of stable, vascular-plant derived DOC while increasing the transfer of biolabile soil C to the atmosphere. © 2019 John Wiley & Sons Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/159036
Appears in Collections: 气候变化与战略
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作者单位: National High Magnetic Field Laboratory Geochemistry Group and Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL, United States; Department of Environmental Systems Science, ETH Zürich, Zurich, Switzerland; Department of Chemistry, Pontchartrain Institute for Environmental Sciences, University of New Orleans, New Orleans, LA, United States; Institut de Recherche en Sciences et Exactes et Naturelles, Brazzaville, Congo
Recommended Citation:
Drake T.W.,Podgorski D.C.,Dinga B.,et al. Land-use controls on carbon biogeochemistry in lowland streams of the Congo Basin[J]. Global Change Biology,2020-01-01,26(3)