Sediment Temperature and Redox Potential As Confound Factors Controlling CO2 Flux Between Sediment and the Atmosphere in an Intertidal Zone

Variation in soil temperature can account for most of the seasonal and diel variation in soil CO₂ flux, but the temperature effect is not consistent in the intertidal zone, and other factors such as redox potential are known to influence CO₂ flux. The objectives of this research were to study the temporal variation in CO₂ flux between sediment and atmosphere in an intertidal zone and to evaluate temperature and redox potential functions as predictors of CO₂ flux. The CO₂ fluxes were measured with chambers two or three days every other week from April 24 to July 26, 2006 in an intertidal zone, Qingdao. The daytime average CO₂ flux between the sediment and the atmosphere was highly related to sediment redox potential. In addition, when eliminating the impact of redox potential, the daytime average CO₂ flux was also related to sediment temperature. The Q₁₀ values based on Flux = R₀e^kT was consistent with the basic hypothesis that soil respiration would double with an increment of 10degC (i.e. Q₁₀=2), when fitting the data at different redox potential independently in this study. Based on the response of CO₂ flux to temperature and redox potential, the equation including temperature and redox potential estimated CO₂ flux better than equations only including temperature or redox potential.