CO2 Fluxes in Mangrove Ecosystems

Abstract

Mangroves have long been recognized as a potential sink of carbon owing to their high productivity and carbon sequestration potential. The short term CO2 dynamics of mangroves are often put under lenses to examine their potential to combat the human induced CO2 emission. Mainly three types of CO2 fluxes take place within a mangrove ecosystem namely (i) atmosphere-biosphere CO2 exchange, (ii) soil CO2 efflux and (iii) air-water CO2 flux. In this chapter, we have compiled all types of the CO2 flux data from mangrove ecosystems with special emphasis on the Sundarban, the world’s largest mangrove forest and analyzed the regulating factors of these fluxes. Summarizing all the studies, it can be inferred that the terrestrial compartments of mangroves acts as net sink for CO2, though the soil continually emit CO2 (apart from few exceptions). Almost all the mangrove surrounding waters act as source of CO2, however, the magnitude of air-water CO2 fluxes are much less than the inward fluxes of CO2towards the canopy, hence the ecosystem as a whole acts as a net sink for CO2. Light conditions, air temperature, salinity, tidal cycle and so forth are mainly found to regulate the atmosphere-biosphere CO2 flux, whereas, soil temperature, moisture and waterlogging are the principal factors regulating the soil CO2fluxes. In case of air-water fluxes, the main governing factors are the variation in salinity, pore-water flushing during ebb tide and wind speed.