QUANTITATIVE ASSESSMENT OF MICROBIAL PRECIPITATION IN ALGAL MAT FROM LAGOA VERMELHA, BRAZIL

The objective of this study is to determine the volume and nature of mineral precipitation in a microbial mat collected in 2009 in Brazil from the Lagoa Vermelha salt pond. Lagoa Vermelha salt pond is a shallow, hypersaline lagoon located on the coast of Brazil, 100 kilometers east of Rio do Janeiro. The sample studied consisted of laminated communities of prokaryotes and was kept alive in a large watch glass filled with aquarium salt water. Visual assessment of photographs taken at the field site in 2009 compared to photographs taken in 2016 show that the percentage of precipitate has increased significantly. Photoshop software was used to determine the total number of pixels that make up the microbial mat, and the amount of pixels that make up the mineral precipitate. From there, the percentage of mineral precipitation visible in the microbial mat was determined. By comparing the percentages from 2009 to 2016, it was determined that the amount of mineral precipitation visible in the microbial mat has increased by 754.02%, while the surface area of the microbial mat has decreased by 14.41%. Images of the microbial mat taken with petrographic microscope and SEM confirm that the volume of precipitate has increased. These observations suggest that precipitation increases as the microbial mat ages and document a geologically rapid rate of lithification. Study of microbes and associated precipitates have potential application to biotechnology, aquaculture, bioremediation, medicine, and astrobiology.