Variabilidade sazonal da condutancia estomática em um ecossistema de manguezal amaz?nico e suas rela??es com variáveis meteorológicas

摘要

This work investigated the variations of stomatal conductance (gs) in the rainy and dry seasons and its dependence relations with meteorological variables measured in an Amazonian mangrove ecosystem. Data were originated from the ECOBIOMA project, part of the Large Scale Biosphere-Atmosphere Experiment in Amazon (LBA). Stomatal conductance followed the tendency of the radiation balance variation, reaching maximum values during the day and minimum values at night. The conductance showed greater fluctuations in the rainy season, with mean value of gs = 0.015 m s-1, however smaller in magnitude than in the dry season. During the dry season, the mean value was gs = 0.027 m s-1, with lower range, varying between 0.010 and 0.042 m s-1. The meteorological variables used for establishing the dependence relations with the daily variability of stomatal conductance were the following; specific moisture deficit (δq), vapor pressure deficit (PVD), net radiation (Rn) and wind velocity (Vv). The PVD showed the best correlation with gs, with R2 = 0.99 for both periods. In spite of the importance of Vv in the gaseous changes between the vegetation and the atmosphere, it presented the smallest influence in the mean variation of the gs, with R2 = 0,44 for the rainy and R2 =0,51 for the dry period.