Sediment temperature and redox potential as confound factors controlling CO2 flux between sediment and the atmosphere in an intertidal zone

摘要

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=R0ekT was consistent with the basic hypothesis that soil respiration would double with an increment of 10°C (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.