In order to better understand the spatiotemporal variations and interrelationships of greenhouse gases (GHG), monthly surface fluxes and profile concentrations of GHG (CO2, N2O and CH4) in karst areas in the Guizhou Province, southwest China, were measured from June 2006 to May 2007. GHG fluxes showed high variability, with a range of 460.9-1,281.2 mg m(-2) h(-1) for CO2, -25.4 to 81.5 mu g m(-2) h(-1) for N2O and -28.7 to -274.9 mu g m(-2) h(-1) for CH4, but no obvious seasonal change trends of the fluxes existed. Profile concentrations of CO2, N2O and CH4 varied between 0.5 and 31.5 mL L-1, 0.273 and 0.734, and 0.1 and 3.5 mu L L-1, respectively. In general, concentrations of CO2 and N2O increased with depth, while CH4 had an inverse trend. However, in October, November and January, the reversal of depth patterns of GHG concentrations took place below 15 cm, close to the soil-rock interface. The spatiotemporal distribution of CO2 in soil profile was significantly positively correlated with that of N2O (p < 0.05-0.01) and negatively correlated with that of CH4 (p < 0.01). The correlation analysis showed that soil temperature and moisture may be responsible for GHG dynamics in the soils, rather than the exchange of GHG between land and atmosphere.
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