Du är här

Trends in CO2 exchange in a high Arctic tundra heath, 2000-2010

Författare:
  • Magnus Lund
  • Julie Maria Falk
  • Thomas Friborg
  • Herbert N. Mbufong
  • Charlotte Sigsgaard
  • Henrik Soegaard
  • Mikkel P. Tamstorf
Publiceringsår: 2012
Språk: Engelska
Publikation/Tidskrift/Serie: Journal of Geophysical Research-Biogeosciences
Volym: 117
Dokumenttyp: Artikel
Förlag: Amer Geophysical Union

Sammanfattning

We have measured the land-atmosphere CO2 exchange using the eddy covariance technique in a high Arctic tundra heath in northeast Greenland (Zackenberg). On the basis of 11 years of measurements (2000-2010), it was found that snow cover dynamics was important for the CO2 exchange. The start of CO2 uptake period correlated significantly with timing of snowmelt. Furthermore, for years with deep and long-lasting snowpacks, the following springs showed increased CO2 emission rates. In the first part of the study period, there was an increase of approximately 8 g C m(-2) yr(-1) in both accumulated gross primary production (GPP) and CO2 sink strength during summer. However, in the last few years, there were no significant changes in GPP, whereas ecosystem respiration (R-eco) increased (8.5 g C m(-2) yr(-1)) and ecosystem CO2 sink strength weakened (-4.1 g C m(-2) yr(-1)). It was found that temperature and temperature-related variables (maximum thaw depth and growing degree days) controlled the interannual variation in CO2 exchange. However, while R-eco showed a steady increase with temperature (5.8 g C m(-2) degrees C-1), the initial increase in GPP with temperature leveled off at the high end of observed temperature range. This suggests that future increases in temperature will weaken the ecosystem CO2 sink strength or even turn it into a CO2 source, depending on possible changes in vegetation structure and functioning as a response to a changing climate. If this trend is applicable also to other Arctic ecosystems, it will have implications for our current understanding of Arctic ecosystems dynamics.

Disputation

Nyckelord

  • Earth and Environmental Sciences

Övriga

Published
  • BECC
Yes
  • ISSN: 0148-0227

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

LERU logotype U21 logotype

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