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Contemporary carbon accumulation in a boreal oligotrophic minerogenic mire - a significant sink after accounting for all C-fluxes

Författare:
  • Mats Nilsson
  • Joergen Sagerfors
  • Ishi Buffam
  • Hjalmar Laudon
  • Tobias Eriksson
  • Achim Grelle
  • Leif Klemedtsson
  • Per Weslien
  • Anders Lindroth (Professor)
Publiceringsår: 2008
Språk: Engelska
Sidor: 2317-2332
Publikation/Tidskrift/Serie: Global Change Biology
Volym: 14
Nummer: 10
Dokumenttyp: Artikel
Förlag: Blackwell Publishing Ltd

Sammanfattning

Based on theories of mire development and responses to a changing climate, the current role of mires as a net carbon sink has been questioned. A rigorous evaluation of the current net C-exchange in mires requires measurements of all relevant fluxes. Estimates of annual total carbon budgets in mires are still very limited. Here, we present a full carbon budget over 2 years for a boreal minerogenic oligotrophic mire in northern Sweden (64 degrees 11'N, 19 degrees 33'E). Data on the following fluxes were collected: land-atmosphere CO2 exchange (continuous Eddy covariance measurements) and CH4 exchange (static chambers during the snow free period); TOC (total organic carbon) in precipitation; loss of TOC, dissolved inorganic carbon (DIC) and CH4 through stream water runoff (continuous discharge measurements and regular C-concentration measurements). The mire constituted a net sink of 27 +/- 3.4 (+/- SD) g C m(-2) yr(-1) during 2004 and 20 +/- 3.4 g C m(-2) yr(-1) during 2005. This could be partitioned into an annual surface-atmosphere CO2 net uptake of 55 +/- 1.9 g C m(-2) yr(-1) during 2004 and 48 +/- 1.6 g C m(-2) yr(-1) during 2005. The annual NEE was further separated into a net uptake season, with an uptake of 92 g C m(-2) yr(-1) during 2004 and 86 g C m(-2) yr(-1) during 2005, and a net loss season with a loss of 37 g C m(-2) yr(-1) during 2004 and 38 g C m(-2) yr(-1) during 2005. Of the annual net CO2-C uptake, 37% and 31% was lost through runoff (with runoff TOC > DIC >> CH4) and 16% and 29% through methane emission during 2004 and 2005, respectively. This mire is still a significant C-sink, with carbon accumulation rates comparable to the long-term Holocene C-accumulation, and higher than the C-accumulation during the late Holocene in the region.

Disputation

Nyckelord

  • Earth and Environmental Sciences
  • peat
  • NEE
  • NECB
  • methane
  • Eddy covariance
  • DOC
  • boreal mire
  • carbon balance
  • runoff
  • Sphagnum
  • TOC

Övriga

Published
Yes
  • ISSN: 1354-1013

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