Water retention and soil organic carbon storage in tropical karst wetlands in Quintana Roo, Mexico

Ecosystem services comprise all the benefits that humanity obtains from ecosystems. Within the regulation services, wetlands soils have an important role in regulating the water cycle through water retention and the climate through carbon storage and sequestration. The objective of this research was to estimate the water retention capacity and the soil organic carbon content in the superficial portion of Ramsar wetlands soils in Quintana Roo, Mexico, to provide elements to the ecologic and economic valuation of regulation ecosystem services. A total of 268 soil samples were collected from the upper 20 cm soil layer, soil samples were processed and analyzed to obtain edaphic properties and organic carbon. We assessed the effect of 1) seasonality, 2) vegetation structure, and 3) soil type in the response variables water retention and organic carbon storage. The results indicate that the volumetric content and saturation degree were different among wetlands. Seasonality was not a significant factor in the assessment of these two regulation ecosystem services. The mean water storage capacity was 0.65 g water/cm³ of soil, representing from 500 to 1000 L water/m³ soil. The greatest carbon storage values were associated with mangroves established on Solonchak, with values between 5 and 8 Mg C/ha. The type of soil is the grouping variable that reported differences in water and carbon content in the soil, with Histosols retaining more water, but Solonchacks storing more carbon.