Diurnal and seasonal patterns of soil CO efflux from the Pichavaram mangroves, India.

The diurnal and seasonal variation of soil carbon dioxide (CO) flux was measured in the Pichavaram mangrove forest, the Southeast coast of India from February 2016 to October 2016 using an automated soil CO flux chamber system. Maximum soil CO efflux reached at 14:00 h and minimum at 00:00 h. The surface soil CO concentration ranged from 375 to 532 ppm with the mean 405 ± 18 ppm. The daily soil CO flux varied from near zero to about 7 μmol m s with a mean value of 2.4 ± 1.3 μmol m s. The highest seasonal CO efflux from soil was during the summer and premonsoon seasons, whereas low flux values were recorded during the monsoon season. Soil CO efflux values were highly correlated with soil temperature. Tidal inundation during monsoon season, extreme drought condition in summer, and unusual precipitation are the major factors controlling the soil CO flux.