Compostos Orgânicos Voláteis Biogênicos Emitidos A Partir da Decomposição de Folhas de Serapilheira na Amazônia Central

Abstract

It is known that a wide chemical diversity of biogenic volatile organic compounds (BVOCs) can be emitted by leaf-litter in different regions and that these compounds have diverse functions within the ecosystem, mediating important soil-plant-atmosphere interactions. However, we do not know the contribution of this compartment in tropical soils, especially in the Amazon, which is responsible for the largest emissions of BVOCs to the global atmosphere. Here, we investigate the emission of BVOCs in a litterbag experiment of leaf decomposition in the terra firme area of central Amazonia. Initially, we characterized emission seeking to understand the magnitude and chemical diversity of BVOCs emitted by leaves at different decomposition times; afterward, we related emission to microorganism dynamics and litter characteristics. Twenty-one BVOCs (oxygenated and isoprenoids) were observed over 229 days of leaf decomposition. The early stages of leaf litter decomposition proved to be more important in the emission of BVOCs than late stages, both in magnitude and chemical diversity, which was probably related to the amount of leaf mass available. Microbial biomass and activity, and litter characteristics, showed no significant correlations with BVOC concentration when considering the whole decomposition study, except for sesquiterpenes and leaf water content (LWC, %). Although the results of this study cannot be generalized and are still very preliminary towards understanding the processes that control BVOC exchanges between soil-litter-atmosphere, it provides a characterization of the compounds that can be found below the canopy during leaf decomposition in central Amazonia.