Wenxin Zhang
Forskare
Process‐Oriented Modeling of a High Arctic Tundra Ecosystem: Long‐Term Carbon Budget and Ecosystem Responses to Interannual Variations of Climate
Författare
Summary, in English
Terrestrial carbon (C) cycling in high Arctic tundra depends on ecosystem responses to
climatic warming and concurrent changes in environmental conditions. There are very few studies to
quantify long-term C budget in high Arctic tundra due to lack of sufficient measurements. Here based on
well-established multiyear measurements, we calibrated a process-oriented model (CoupModel) to quantify
various components of the C budget at a Cassiope tetragona heath ecosystem in northeast Greenland. Net
ecosystem exchange of CO
2
(NEE) for 2000–2014 was estimated at 15 ± 10 g C m
2
yr
1
. Ecosystem
respiration (ER) for nongrowing seasons was estimated at 10.3 ± 5.3 g C m
2
yr
1
, representing around
13% of the annual ER. Significant trends for interannual variations of aboveground and belowground C fluxes
and stocks were found for the subperiods (i.e., 2000–2008 and 2008–2014) but not for the entire period.
Interannual variations of NEE largely relied on the response of gross primary production (GPP) and ER to
seasonal changes in climate. Moreover, the model showed that interannual variations of GPP, ER, and NEE
had a much higher linear correlation with July temperature and annual maximum thawing depth (ALD
max
)
than other climatic and site characteristics. ALD
max
had the highest correlation with the decomposition rate
of humus C. Overall, this modeling study suggests that a sink-source transition of the studied ecosystem
depends on ecosystem responses to interannual variations of climate and that the net C balance may be
sensitive to summer warmth and active layer thickness.
climatic warming and concurrent changes in environmental conditions. There are very few studies to
quantify long-term C budget in high Arctic tundra due to lack of sufficient measurements. Here based on
well-established multiyear measurements, we calibrated a process-oriented model (CoupModel) to quantify
various components of the C budget at a Cassiope tetragona heath ecosystem in northeast Greenland. Net
ecosystem exchange of CO
2
(NEE) for 2000–2014 was estimated at 15 ± 10 g C m
2
yr
1
. Ecosystem
respiration (ER) for nongrowing seasons was estimated at 10.3 ± 5.3 g C m
2
yr
1
, representing around
13% of the annual ER. Significant trends for interannual variations of aboveground and belowground C fluxes
and stocks were found for the subperiods (i.e., 2000–2008 and 2008–2014) but not for the entire period.
Interannual variations of NEE largely relied on the response of gross primary production (GPP) and ER to
seasonal changes in climate. Moreover, the model showed that interannual variations of GPP, ER, and NEE
had a much higher linear correlation with July temperature and annual maximum thawing depth (ALD
max
)
than other climatic and site characteristics. ALD
max
had the highest correlation with the decomposition rate
of humus C. Overall, this modeling study suggests that a sink-source transition of the studied ecosystem
depends on ecosystem responses to interannual variations of climate and that the net C balance may be
sensitive to summer warmth and active layer thickness.
Avdelning/ar
- BECC: Biodiversity and Ecosystem services in a Changing Climate
Publiceringsår
2018-03-07
Språk
Engelska
Sidor
1178-1196
Publikation/Tidskrift/Serie
Journal of Geophysical Research - Biogeosciences
Volym
123
Issue
4
Dokumenttyp
Artikel i tidskrift
Förlag
Wiley
Ämne
- Climate Research
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 2169-8953