Amazon Forest Soils are recognized as atmospheric methane sinks. However, the land use change to pasture turn these soils to methane sources. The soil acidity reduction due to the conversion of forest to pasture is a relevant factor in the soil's methane sink capacity. Preliminary results of this doctoral research indicate that the amendment of Amazon soils acidity by liming reduces the methane sink capacity and influences the abundance of microorganisms associated with the process (consumers/ producers), but not the composition of the methane cycling communities. It is proposed here to determine the effect of the acidity correction, in the context of Amazon land use change, on the active microbiota that sequesters methane (methanotrophic), since the activity of these microorganisms is an essential dimension for the understanding of the process. This project will continue the plan already started, fulfilling at the end a study with soils of the Amazon region (East and West) under Primary Forest, Pastures with conserved vegetation cover and Pastures in a state of degradation. An experiment is in the final phase, evaluating: the effect of pH correction (6.5 in H2O) and the cover by Brachiaria bryzantha cv. Marandú on gas fluxes CH4 and CO2, the soil number of copies of the genes pmoA1, pmoA2, mmoX, mcrA, 16S Bacteria and 16S Archaea and the composition of Bacteria and Archaea community (sequencing of amplicons 16S). For the study of the active microbiota, DNA - Stable Isotopic Probings (SIP) will be used focused on the methane-consuming community 13C-CH4 by metagenomic analysis, aiming to determine the biochemical pathways used by these micro-organisms, the abundance of genes and shifts in the community structure. It is expected to contribute with the knowledge regarding practices to mitigate the impact of livestock in CH4 emissions, and to contribute to the value of the forest conservation.
News published in Agência FAPESP Newsletter about the scholarship: