Aporte de matéria orgânica oriunda de planície de inundação em ambiente aquático na Amazônia Central (PA)

Abstract

The Amazonian flood plain ecosystems are mainly controlled by the seasonal pattern of variation in the water level, the so called flood pulse. This phenomenon is considered the main agent modelling the dynamics as well as the structure of communities and the dominant processes in flood plain aquatic ecosystems. During high water periods there are considerable linkages between the distinct ecosystems present at the flood plain. Thus there is a remarkable energy exchange, mainly represented by the organic matter pool of the forest soil. Researches have been showing that many lakes along the world are dominated by the heterotrophic metabolism. It has been suggested that aquatic ecosystems in which the respiration rates overcome the primary production rates are subsided by allochthonous energy. After the incorporated by bacterial biomass, the nutrients derived from the organic matter become available to other living organisms. The present work aimed to (1) quantify the input of carbon, nitrogen and phosphorus derived from the Batata Lake flood plain litter and (2) quantify the production of CO2 in terms of saturation with the atmosphere and the contribution of energy sources with different origins for the balance of carbon mediated by bacterial metabolism in the Amazon ecosystem of clear water. This study indicated that the flood plain morphology, the composition and the conservation of the igapó forest and also the flood pulse are important on quantifying the terrestrial organic matter input to the aquatic systems. Then, modifications on these parameters reflect directly on the aquatic metabolism. This study also approached the importance of the substrate quality on bacterial x metabolism and its implications on the carbon cycle. It was observed that the organic matter quality and quantity potentially affect the bio-structure and the productivity of Amazonian.