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Moisture effects on temperature sensitivity of CO2 exchange in a subarctic heath ecosystem

Illeris, L; Christensen, Torben LU and Mastepanov, Mikhail LU (2004) In Biogeochemistry 70(3). p.315-330
Abstract
Carbon fluxes between natural ecosystems and the atmosphere have received increased attention in recent years due to the impact they have on climate. In order to investigate independently how soil moisture and temperature control carbon fluxes into and out of a dry subarctic dwarf shrub dominated heath, monoliths containing soil and plants were incubated at three different moisture levels and subjected to four different temperature levels between 7 and 20degreesC. Ecosystem CO2 exchange was monitored continuously day and night during the 16 to 18 days that each of three experiments lasted. Additionally, the carbon allocation pattern of the plants was investigated by labelling monoliths with (CO2)-C-14 followed by harvest of above and below... (More)
Carbon fluxes between natural ecosystems and the atmosphere have received increased attention in recent years due to the impact they have on climate. In order to investigate independently how soil moisture and temperature control carbon fluxes into and out of a dry subarctic dwarf shrub dominated heath, monoliths containing soil and plants were incubated at three different moisture levels and subjected to four different temperature levels between 7 and 20degreesC. Ecosystem CO2 exchange was monitored continuously day and night during the 16 to 18 days that each of three experiments lasted. Additionally, the carbon allocation pattern of the plants was investigated by labelling monoliths with (CO2)-C-14 followed by harvest of above and below ground plant parts. The results revealed that the three different soil moisture levels caused distinctly differing levels Of CO2 fluxes. Also, both carbon fixation calculated as gross ecosystem production (GEP) and carbon release measured as ecosystem respiration (ER) increased with increasing temperatures, with ER increasing faster than GER Hence, short term carbon loss from the ecosystem accelerated with raised temperatures. Temperature sensitivity of the ecosystem was dependent on the soil moisture level, shown by differing Q(10) values of both GEP and ER at different soil moisture levels. It is therefore highly important to take soil moisture levels into consideration when evaluating responses of ecosystem carbon balance to changes in temperature. The greatest C fixation took place via the two most dominant species of the ecosystem, Vaccinium uliginosum and Empetrum hermaphroditum, with the former being responsible for the different size of C fixation at the three moisture levels. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
soil respiration, soil moisture, dry tundra, Arctic, carbon flux, temperature sensitivity
in
Biogeochemistry
volume
70
issue
3
pages
315 - 330
publisher
Springer
external identifiers
  • wos:000226519100002
  • scopus:84856505382
ISSN
1573-515X
DOI
10.1007/s10533-003-0855-2
language
English
LU publication?
yes
id
581a24c0-9acf-4c4a-9825-2e26b109cc53 (old id 254982)
date added to LUP
2007-10-23 09:34:13
date last changed
2017-12-10 03:49:03
@article{581a24c0-9acf-4c4a-9825-2e26b109cc53,
  abstract     = {Carbon fluxes between natural ecosystems and the atmosphere have received increased attention in recent years due to the impact they have on climate. In order to investigate independently how soil moisture and temperature control carbon fluxes into and out of a dry subarctic dwarf shrub dominated heath, monoliths containing soil and plants were incubated at three different moisture levels and subjected to four different temperature levels between 7 and 20degreesC. Ecosystem CO2 exchange was monitored continuously day and night during the 16 to 18 days that each of three experiments lasted. Additionally, the carbon allocation pattern of the plants was investigated by labelling monoliths with (CO2)-C-14 followed by harvest of above and below ground plant parts. The results revealed that the three different soil moisture levels caused distinctly differing levels Of CO2 fluxes. Also, both carbon fixation calculated as gross ecosystem production (GEP) and carbon release measured as ecosystem respiration (ER) increased with increasing temperatures, with ER increasing faster than GER Hence, short term carbon loss from the ecosystem accelerated with raised temperatures. Temperature sensitivity of the ecosystem was dependent on the soil moisture level, shown by differing Q(10) values of both GEP and ER at different soil moisture levels. It is therefore highly important to take soil moisture levels into consideration when evaluating responses of ecosystem carbon balance to changes in temperature. The greatest C fixation took place via the two most dominant species of the ecosystem, Vaccinium uliginosum and Empetrum hermaphroditum, with the former being responsible for the different size of C fixation at the three moisture levels.},
  author       = {Illeris, L and Christensen, Torben and Mastepanov, Mikhail},
  issn         = {1573-515X},
  keyword      = {soil respiration,soil moisture,dry tundra,Arctic,carbon flux,temperature sensitivity},
  language     = {eng},
  number       = {3},
  pages        = {315--330},
  publisher    = {Springer},
  series       = {Biogeochemistry},
  title        = {Moisture effects on temperature sensitivity of CO2 exchange in a subarctic heath ecosystem},
  url          = {http://dx.doi.org/10.1007/s10533-003-0855-2},
  volume       = {70},
  year         = {2004},
}