摘要:The aim of this work was to quantify the biopolymers associated to esterase enzymes and identify the bacterial respiratory activity in two cores collected in Jurujuba Sound, Guanabara Bay, Rio de Janeiro State. Biopolymer concentrations were ten times less than reported in the literature, rendering necessary the creation and establishment of new eutrophication levels indices more compatible with Brazilian coastal systems. The biochemical representative relationship in the cores was equivalent to the available data for coastal marine environments. The amount of esterase enzymes in the sediment proved that the mineralization of biopolymers is in continuous process, even with preferentially anaerobic metabolism. Despite the fact that geomicrobiology studies are incipient, this study’s results indicate the possible application of microbiology for providing a better understanding of the geochemical processes in tropical environment.