Occurence of archaea in a man-made freshwater reservoir of tropical semiarid region

Abstract

This work aimed to analyze seasonal variations in bacterioplankton and archaeplankton community composition and evaluate possible influences of limnological and climatic variables on the prokaryotic communities in the water column of the Armando Ribeiro Gonçalves Dam during three consecutive years. Polymerase Chain Reaction (PCR) and Denaturing Gradient Gel Electrophoresis (DGGE) were were used to analyze the compositions of the heterotrophic prokaryotic communities of the reservoir influenced by alternating periods of rain and drought. Bacterial and archaeal abundance, and DGGE bands richness were influenced by pluviosity, water temperature, and total phosphorus (TP). Principal Component Analysis (PCA) showed strong correlations among these variables. Canonical Correspondence Analysis (CCA) evidenced temporal shifts on bacterial and archaeal community composition, associated with the pluviosity, reservoir volume, water temperature, and prokaryotic density. This suggests the predominance of factors associated to precipitation events on microbial community structure, that is probably composed by persistent and transitory populations wich may influence the environmental quality, including archaeal populations. Highlight of archaeal occurrence in the reservoir opens a new research view for next studies on the interactions of microbial communities and consequences of their activities.