Evaluación de la comunidad desnitrificante nosZ en la columna de agua de Isla del Sol, embalse de Prado, Tolima

Abstract

In the present study the genetic diversity of denitrifying communities related to the recycling of greenhouse gas nitrous oxide (N2O) in Isla del Sol water column, Prado dam (Tolima), was analyzed using the terminal restriction fragment lenght polymorphism analysis of the nosZ functional gene, which encodes the N2O reduction to N2 during denitrification. This is the first report demonstrating the presence of nosZ-type denitrifying microorganisms in a Colombian acquatic ecosystem. The results indicated that digestion with the MspI enzyme generated a better nosZ community profile (expresed in an increase of terminal restriction fragments - TRF) than the HhaI enzyme. Besides, the nosZ community had a higher TRF richness and diversity (Shannon index - H′=0.9) at the depth (9m) where suboxic conditions (1.1 mg/L O2), as well as high nitrate levels (0.78 mg/L) were found, which could favoured N2O reduction to N2. These results are the base for future studies on the functionality and significance of such communities for the regulation of N2O emissions from this dam.