Analysis of the methane cycle-associated microbiota in areas of primary forest, pasture and secondary forest in the Amazon

Abstract

The Amazon Basin is covered by the largest existing tropical rainforest, in which approximately 15% of its original cover has been replaced by areas designed to meet growing food demand in a process that alters the original physical, chemical and biological properties of the soil. Soil diversity consists mainly of Archaea and Bacteria microorganisms, which are necessary for the functioning of terrestrial ecosystems for their role in nutrient cycling and biogeochemical cycles. However, these respond quickly to land-use change processes, in order to be an important tool for environmental quality analysis and to provide comparative parameters between them. In this sense, anthropogenic land use has the potential to alter soil gas flow by its effect on the structure and functioning of the microbiota, including that associated with the biogeochemical cycle of methane (CH4), the second most important greenhouse gas. The soil methane exchange with the atmosphere and, consequently, its quantity in it is regulated by methanogenic microorganisms, methane producing archaea; and methanotrophic bacteria that consume the same gas, so that the two groups differ according to their unique ecological and biochemical characteristics. Within this context, the real-time quantitative PCR (qPCR) technique, which allows the calculation of the initial amount of genes of interest in environmental samples, can be used to detect and quantify the soil Archaea and Bacteria communities, as well as specifically their methanogenic representatives, by the mcrA gene analysis, and methanotrophic representatives, by the pmoA and mmoX genes, respectively. Therefore, the objective of the research project is to determine the effect of land use on the abundance of Archaea and Bacteria communities, with emphasis on functional genes associated with the methane biogeochemical cycle, in areas under different uses in the state of Pará, in the eastern Amazon. (AU)