Du är här

Trace gas exchange in a high-arctic valley 1. Variations in CO2 and CH4 flux between tundra vegetation types

Författare:
  • Torben Christensen
  • T Friborg
  • M Sommerkorn
  • J Kaplan
  • L Illeris
  • H Sögaard
  • C Nordström
  • S Jonasson
Publiceringsår: 2000
Språk: Engelska
Sidor: 701-714
Publikation/Tidskrift/Serie: Global Biogeochemical Cycles
Volym: 14
Nummer: 3
Dokumenttyp: Artikel
Förlag: American Geophysical Union (AGU)

Sammanfattning

Ecosystem exchanges of CO2 and CH4 were studied by chamber techniques in five different vegetation types in a high arctic valley at Zackenberg, NE Greenland. The vegetation types were categorized as Cassiope heath, hummocky fen, continuous fen, grass land and Salix arctica snowbed. Integrated daytime fluxes for the different vegetation types of the valley showed that the fen areas and the grassland, were significant sources of CH4 with a mean efflux of 6.3 mg CH4 m(-2) h(-1) and sinks for CO2, with almost -170 mg CO2 m(-2) hr(-1). The heath and snowbed areas had much lower carbon sequestration rates of about -25 mg CO2 m(-2) hr(-1) and were also sinks for CH4. Methane emissions from the valley dominated in the hummocky fens. Computation of area integrated mean daytime flux values across all vegetation types of the entire valley bottom revealed that it was a sink of CO2 in the order of -96+/-33 mg CO2 m-2 hr-1 and a source of 1.9+/-0.7 m(-2) CH4 m(-2) hr(-1). These values were in accordance with eddy correlation measurements reported elsewhere in this issue and reflect a high-carbon exchange despite the high arctic location. In the fens, where the water table was at or above the soil surface, methane emissions increased with net ecosystem CO2 flux. In places with the water table below the soil surface, such as particularly in the hummocky parts of the fen, oxidation tended to become the dominant controlling factor on methane efflux.

Disputation

Nyckelord

  • Biology and Life Sciences

Övrigt

Published
Yes
  • ISSN: 0886-6236

Box 117, 221 00 LUND
Telefon 046-222 00 00 (växel)
Telefax 046-222 47 20
lu [at] lu [dot] se

Fakturaadress: Box 188, 221 00 LUND
Organisationsnummer: 202100-3211
Om webbplatsen

LERU logo U21 logo