CO2 na floresta nativa de Caxiuanã - Melgaço/PA.

Abstract

Studies about CO2 flux in the Amazon suggest seasonal variation in energy and matter exchange between their ecosystems and the atmosphere. According to evidences, the forest behavior as a carbon source or sink is sensitive to seasonal fluctuation of rainfall, which in turn is influenced by macro scale events at a global level. Therefore, we analyzed the daily and hourly climatic variability of CO2 flux in the eastern Amazon during 2007 and 2008. The behavior patterns of matter and energy fluxes were related to the seasonal rainfall and the oscillation of the Oceanic Niño Index. The results were expressed for the Revista Brasileira de Iniciação Científica, Itapetininga, v. 4, n. 9, 2017. 35 two seasons of each year. The CO2, H2O and energy fluxes data were computed according to the Eddy Covariance technique. The instruments are placed in a micrometeorological tower at the Caxiuanã National Forest. The average rate of net ecosystem production peaks in this ecosystem ranged from -22.97 to -37.33 μmol de CO2 m-2 s-1 for the diurnal cycles of 2007 and 2008. In the first year, there was no significant variation of influx. On the other hand, on 2008 there was a notorious seasonal variability in CO2 capture by the forest. These behaviors were performed due to the dynamics of the energy flux and the water availability. The net ecosystem production budget of this site was estimated at -8.72 t C ha-1 year- 1 during the approached period. It is noteworthy that the period may had been a productive one due to the absence of a strong El Niño anomaly.