Hydrology and carbon dynamics of tropical peatlands from Southeast Brazil

Abstract

Peatlands are important natural carbon reservoirs and regulators of water flow and of its dynamic in many natural areas. The structural integrity of these systems has been recognizably threatened by anthropic interventions but has also been significantly influenced by the global climate changes. This study aimed to characterize the water and carbon dynamics in watersheds of two peats independently supplying the Araçuaí River basin in the northeastern Minas Gerais state, Brazil. The peats, which were found to be in different states of natural conservation, were investigated for their physical and chemical characteristics, both of the peats and of their stored water. The 14C isotopic analyses of the peat and measurements of the water and organic carbon storage capacity of these peats were performed. The geneses of the corresponding profiles were found to have initiated between the early Holocene (7664 years BP) and the late Pleistocene (11,129 years BP) periods with a vertical growing rate between 0.10 and 0.61 mm y− 1. The difference in the degree of natural conservation on the dynamic of water and carbon between these peats was checked by the water and soil attributes. Large quantities of water (mean value for these two peats, approximately 10,108 m3 ha− 1) and organic carbon (200 ton C ha− 1) were presumably stored during its pedogenetic history. The more anthropically altered peat presented a negative carbon balance and lower water flow in the dry season. The influence of human activities on their carbon and water dynamics reinforces the importance of protecting and conserving these native areas.