Preliminary studies on methane flux from the ornithogenic soils on Xi-sha atoll, South China Sea.
Methane flux from the ornithogenic soils was preliminarily measured by closed chamber method on Xi-sha atoll, South China Sea during March 10 to April 11, 2003 for the first time. The CH4 flux ranged from -4226.7 microg/(m2 x h) to 226.3 microg/(m2 x h) at the observation sites on Dong Island. High atmospheric CH4 consumption was observed from the ornithogenic soils on sunny days. CH4 uptake rates showed the highest value after the midday and they had a strong positive correlation with soil temperatures. Under the same weather conditions, the CH4 fluxes were also observed from the intact and disturbed soils on Yongxing Island. Results showed that the intact soils with natural vegetation also showed high atmospheric CH4 consumption and the average flux was -141.8 microg/(m2 x h). However, disturbed soils via anthropogenic reclamation showed CH4 emissions and the average flux was 441.7 microg/(m2 x h). Therefore land use changes may have an important effect on the CH4 fluxes from the tropical ornithogenic soils. In addition, different observation sites show a high spatial variation in CH4 fluxes. The wetland in salt marsh showed the CH4 emission on Dong Island, and the dry soil sites all showed high atmospheric CH4 consumption, suggesting that CH4 fluxes were predominantly controlled by soil water regime. The effects of soil chemical properties on CH4 fluxes were also analyzed and discussed in this paper.
Zhu
Ren-bin
RB
Institute of Polar Environment, University of Science and Technology of China, Hefei, 230026, China.
Sun
Li-guang
LG
Zhao
San-ping
SP
Xie
Zhou-qing
ZQ
Liu
Xiao-dong
XD
Yin
Xue-bin
XB
D001272:Atmosphere / Q000032:analysis*; D002681:China; D005843:Geography; D007700:Kinetics; D008697:Methane / Q000737:chemistry*; D011891:Rain; D012987:Soil / Q000032:analysis*; D013696:Temperature
D012987:Soil; D008697:Methane