A influência da variabilidade espacial e sazonal sobre o efluxo de dióxido de carbono do solo em ambientes modificados na FLONA Caxiuanã-PA

Abstract

This study aimed to investigate the influence of spatial and seasonal variability on the efflux of CO2 from the soil to the atmosphere by comparing with heat sensitive streams and latent heat as with the environmental variables (air and soil temperature, relative humidity and volumetric soil moisture) and total organic carbon in soil. This study was conducted in environments modified naturally (AMN) and antropicamente (AMA) on the FLONA of Caxiuanã, PA, during the transitional period of rainy-dry season and dry period in the year 2013. We have seen that the opening of anthropogenic and natural gaps promote variations of environmental factors arriving at the interior of the modified environments, causing greater intensity in the heat flux, favoring thus the spatial variability of CO2 efflux. The AMN showed an increase of CO2 efflux from the period of transition from the rainy–dry season to the dry period, where the highest rates of efflux occurred in the afternoon with the removal of the gap to the interior of the forest under closed canopy in east and west the gap. Contrasting with the AMA where it was verified reduction of rates of efflux of the transitional period of rainy– dry season to the dry period. Correlations between soil temperature and soil moisture with the CO2 efflux presented significant correlation mainly in the center of the gaps, influenced by heat transport more intense at this location. In this way, the CO2 efflux receives influence of environmental micrometeorological variables, soil physical and chemical characteristics and contribution of total organic carbon, showing variations of behavior with the opening of natural gap and anthropized in the Amazon rainforest.