TY - JOUR
T1 - Evaluation of CO 2 exchange rates in a wetland ecosystem using the closed geosphere experiment facility
AU - Suzuki, Shizuo
AU - Yokozawa, Masayuki
AU - Inubushi, Kazuyuki
AU - Hara, Toshihiko
AU - Kimura, Michitoshi
AU - Tsuga, Shoichi
AU - Tako, Yasuhiro
AU - Nakamura, Yuji
PY - 2012
Y1 - 2012
N2 - To evaluate annual CO 2 exchange rates in a wetland ecosystem, ecosystem respiration rate (R e), net ecosystem productivity (NEP), and gross primary productivity (GPP) were investigated using the Closed Geosphere Experiment Facility (CGEF) located in northeastern Japan. The CGEFis highly airtight and equipped with a Geosphere Module (GM). TheGMhas a ground area of 5.8 3 8.7 m 2 and an average height of 11.9 m, including a soil depth of 3.1 m. A wetland ecosystem dominated by Phragmites australis was introduced into the CGEF. Air temperature and CO 2 concentration in the GM were controlled automatically. The hourly nighttime R e increased exponentially with the hourly average air temperature. Both hourly NEP and GPP depended on hourly photosynthetic photon flux density (PPFD). In addition, daily ecosystem CO 2 exchange rates (R e, NEP, and GPP) were influenced by above-ground plant biomass. The annual NEP was found to be 64.2 6 19.2 g C m -2 yr -2 and it resulted from the annual GPP of 555.8 6 17.0 g C m -2 yr -2 and annual Re of 2491.6 6 15.6 g C m -2 yr -2. Therefore, the wetland ecosystem behaved as a CO 2 sink for the entire year. The annual CO 2 exchange rates obtained were reasonable values compared to the findings of published studies in P. australis-dominated wild wetlands using the eddy covariance technique and the combined method of internal gas pressures and flow measurements and harvesting.
AB - To evaluate annual CO 2 exchange rates in a wetland ecosystem, ecosystem respiration rate (R e), net ecosystem productivity (NEP), and gross primary productivity (GPP) were investigated using the Closed Geosphere Experiment Facility (CGEF) located in northeastern Japan. The CGEFis highly airtight and equipped with a Geosphere Module (GM). TheGMhas a ground area of 5.8 3 8.7 m 2 and an average height of 11.9 m, including a soil depth of 3.1 m. A wetland ecosystem dominated by Phragmites australis was introduced into the CGEF. Air temperature and CO 2 concentration in the GM were controlled automatically. The hourly nighttime R e increased exponentially with the hourly average air temperature. Both hourly NEP and GPP depended on hourly photosynthetic photon flux density (PPFD). In addition, daily ecosystem CO 2 exchange rates (R e, NEP, and GPP) were influenced by above-ground plant biomass. The annual NEP was found to be 64.2 6 19.2 g C m -2 yr -2 and it resulted from the annual GPP of 555.8 6 17.0 g C m -2 yr -2 and annual Re of 2491.6 6 15.6 g C m -2 yr -2. Therefore, the wetland ecosystem behaved as a CO 2 sink for the entire year. The annual CO 2 exchange rates obtained were reasonable values compared to the findings of published studies in P. australis-dominated wild wetlands using the eddy covariance technique and the combined method of internal gas pressures and flow measurements and harvesting.
KW - Asia
KW - Ecosystem effects
KW - Fluxes
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U2 - 10.1175/JHM-D-10-05033.1
DO - 10.1175/JHM-D-10-05033.1
M3 - Article
AN - SCOPUS:84864752868
VL - 13
SP - 966
EP - 980
JO - Journal of Hydrometeorology
JF - Journal of Hydrometeorology
SN - 1525-755X
IS - 3
ER -