Soil water retention and carbon pools in tropical forested wetlands and marshes of the Gulf of Mexico

The ability of marshes and forested wetlands to provide environmental services (water retention in soil and carbon storage) was evaluated at three locations along the coast of Veracruz, Mexico. Hydro-periods were obtained for the different vegetation communities of marshes and forested wetlands. Total organic carbon contents were 26.2% in Pachira swamp, 23.1% in Ficus swamp and 11.2% in marsh soils. The largest values of hydraulically active pore space were observed for marshes (0.79 cm(3) cm(-3)), and the lowest in forested wetlands (0.57 cm(3) cm(-3)). Soil water holding capacity ranged from 556 to 834 L m(-2) for swamp areas and from 687 to 880 L m(-2) for marshes. The thickness of soil organic layers in the wetland studied had a major control on soil water storage. This suggests that a vast amount of rain water could be retained in the soil. The results indicate that both swamps and marshes play important roles in their capacities to retain water and sequester carbon, although there were no significant differences among them.