Article

Ecosystems

, Volume 9, Issue 7, pp 1041-1050

Reconciling Carbon-cycle Concepts, Terminology, and Methods

  • F. S. ChapinIIIAffiliated withInstitute of Arctic Biology, University of Alaska–Fairbanks Email author 
  • , G. M. WoodwellAffiliated withThe Woods Hole Research Center
  • , J. T. RandersonAffiliated withDepartment of Earth System Science, University of California
  • , E. B. RastetterAffiliated withThe Ecosystem Center, Marine Biological Laboratory
  • , G. M. LovettAffiliated withInstitute of Ecosystem Studies
  • , D. D. BaldocchiAffiliated withDepartment of Environmental Science, Policy, and Management, University of California
  • , D. A. ClarkAffiliated withDepartment of Biology, University of Missouri
  • , M. E. HarmonAffiliated withDepartment of Forest Science, Oregon State University
  • , D. S. SchimelAffiliated withNational Center for Atmospheric Research
    • , R. ValentiniAffiliated withInstitute of Arctic Biology, University of Alaska–FairbanksDepartment of Forest Science and Environment, University of Tuscia
    • , C. WirthAffiliated withInstitute of Arctic Biology, University of Alaska–FairbanksMax-Planck-Institute for Biogeochemistry
    • , J. D. AberAffiliated withInstitute of Arctic Biology, University of Alaska–FairbanksComplex Systems Research Center, University of New Hampshire
    • , J. J. ColeAffiliated withInstitute of Ecosystem Studies
    • , M. L. GouldenAffiliated withDepartment of Earth System Science, University of California
    • , J. W. HardenAffiliated withInstitute of Arctic Biology, University of Alaska–FairbanksUS Geological Survey
    • , M. HeimannAffiliated withInstitute of Arctic Biology, University of Alaska–FairbanksMax-Planck-Institute for Biogeochemistry
    • , R. W. HowarthAffiliated withInstitute of Arctic Biology, University of Alaska–FairbanksDepartment of Ecology and Evolutionary Biology, Cornell University
    • , P. A. MatsonAffiliated withInstitute of Arctic Biology, University of Alaska–FairbanksDepartment of Geological and Environmental Sciences, Stanford University
    • , A. D. McGuireAffiliated withInstitute of Arctic Biology, University of Alaska–FairbanksUS Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska–Fairbanks
    • , J. M. MelilloAffiliated withThe Ecosystem Center, Marine Biological Laboratory
    • , H. A. MooneyAffiliated withInstitute of Arctic Biology, University of Alaska–FairbanksDepartment of Biological Sciences, Stanford University
    • , J. C. NeffAffiliated withInstitute of Arctic Biology, University of Alaska–FairbanksGeological Sciences and Environmental Studies, University of Colorado
    • , R. A. HoughtonAffiliated withThe Woods Hole Research Center
    • , M. L. PaceAffiliated withInstitute of Ecosystem Studies
    • , M. G. RyanAffiliated withInstitute of Arctic Biology, University of Alaska–FairbanksGeological Sciences and Environmental Studies, University of Colorado
    • , S. W. RunningAffiliated withInstitute of Arctic Biology, University of Alaska–FairbanksRocky Mountain Research Station, USDA Forest Service
    • , O. E. SalaAffiliated withThe Woods Hole Research CenterDepartment of Ecology and Evolutionary Biology, Brown University
    • , W. H. SchlesingerAffiliated withThe Woods Hole Research CenterNicholas School of the Environment and Earth, Duke University
    • , E.-D. SchulzeAffiliated withInstitute of Arctic Biology, University of Alaska–FairbanksMax-Planck-Institute for Biogeochemistry

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

Recent projections of climatic change have focused a great deal of scientific and public attention on patterns of carbon (C) cycling as well as its controls, particularly the factors that determine whether an ecosystem is a net source or sink of atmospheric carbon dioxide (CO2). Net ecosystem production (NEP), a central concept in C-cycling research, has been used by scientists to represent two different concepts. We propose that NEP be restricted to just one of its two original definitions—the imbalance between gross primary production (GPP) and ecosystem respiration (ER). We further propose that a new term—net ecosystem carbon balance (NECB)—be applied to the net rate of C accumulation in (or loss from [negative sign]) ecosystems. Net ecosystem carbon balance differs from NEP when C fluxes other than C fixation and respiration occur, or when inorganic C enters or leaves in dissolved form. These fluxes include the leaching loss or lateral transfer of C from the ecosystem; the emission of volatile organic C, methane, and carbon monoxide; and the release of soot and CO2 from fire. Carbon fluxes in addition to NEP are particularly important determinants of NECB over long time scales. However, even over short time scales, they are important in ecosystems such as streams, estuaries, wetlands, and cities. Recent technological advances have led to a diversity of approaches to the measurement of C fluxes at different temporal and spatial scales. These approaches frequently capture different components of NEP or NECB and can therefore be compared across scales only by carefully specifying the fluxes included in the measurements. By explicitly identifying the fluxes that comprise NECB and other components of the C cycle, such as net ecosystem exchange (NEE) and net biome production (NBP), we can provide a less ambiguous framework for understanding and communicating recent changes in the global C cycle.

Keywords

net ecosystem production net ecosystem carbon balance gross primary production ecosystem respiration autotrophic respiration heterotrophic respiration net ecosystem exchange net biome production net primary production