Atmospheric CO₂ flux from mangrove surrounding waters

The partial pressure of CO 2 (pCO 2 ) was measured at daily and weekly time scales in the waters surrounding mangrove forests in Papua New Guinea, the Bahamas and India. The pCO 2 values range from 380 to 4800 μatm. These data, together with previously published data, suggest that overall oversaturation of CO 2 with respect to atmospheric equilibrium in surface waters is a general feature of mangrove forests, though the entire ecosystems (sediment, water and vegetation) are probably sinks for atmospheric CO 2 . The computed CO 2 fluxes converge to about +50 mmolC m −2 day −1 . If this conservative value is extrapolated for worldwide mangrove ecosystems, the global emission of CO 2 to the atmosphere is about 50 10 6 tC year −1 . Based on this tentative estimate, mangrove waters appear to be regionally a significant source of CO 2 to the atmosphere and should be more thoroughly investigated, especially at seasonal time scale.