Chroococcales in blister microbial mats at brejo do Pau Fincado, Rio de Janeiro, Brazil

Abstract

Chroococcales in blister microbial mats at brejo do Pau Fincado, Rio de Janeiro, Brazil. Brejo do Pau Fincado (22º55' 56,75" S e 42º16' 54,7" W) is a natural natural coastal aquatical body. It is located at the Lagoa de Araruama complex, formed at least 7000 years ago. The local climate is characterized by low precipitation rates and high evaporation rates; due to this, the lagoons tend to become hypersalyne. Microbial mats are organic-sedimentary structures composed mainly of cyanobacteria. Whilst the photosynthesis process cyanobacteria induct an environmental change, which leads to calcium carbonate precipitation. The aim of this study was to typify and identify the cyanobacteria at the blister microbial mat. Samples were processed and analyzed using an optical microscope. The blister mat is composed of twelve species of cyanobacteria disposed in a fragile and amorphous mass. In this structure, both quantitative and qualitative domains belong to Chroococcales Westtein 1924. Measurement has shown that the place is very selective, and cyanobacteria presented great resistance and adaptability, because they are forms which had got success surviving to big changes occurred on Earth since the beginning of life and the evolutionary history.