Effects of evaporation on dolomite bioprecipitation by halophilic bacteria from the Araruama Complex

• Grant number: 24/04841-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2024
• End date: June 30, 2025
• Field of knowledge: Physical Sciences and Mathematics - Geosciences
• Principal Investigator: Douglas Galante
• Grantee: Guilherme Aguiar de Lacerda
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

In Earth's present-day sedimentary environments, dolomite precipitation is mostly mediated by microorganisms. The way in which these bacteria are capable of facilitating or inducing biomineralization has not yet been fully elucidated in the literature. However, it is known that some bacteria are capable of producing an EPS (extracellular polymeric substance) matrix that facilitates the formation of an ideal environment for dolomite precipitation. The ability to secrete EPS is extremely widespread among microorganisms and can perform several different functions, including constituting a common mechanism for protecting extremophiles against adverse conditions, including intense evaporation rates from the environment present. In this context, two hypersaline lagoons, Lagoa Vermelha and Brejo do Espinho, located in the Araruama Complex in Brazil, are currently the subject of numerous studies involving the formation of Ca/Mg carbonate, including dolomite. In view of this, the objective of the present project is to analyze the structure, morphology and optical properties of dolomite bioprecipitates (CaMg(CO3)2 generated by halophilic bacteria isolated from the Araruama Complex, under stressful environments, specifically in evaporation conditions. The results obtained in this project will provide a broader study of these microorganisms and their environmental interactions, as well as enrich the knowledge of the mechanisms and characteristics of halophilic bacteria in the hypersaline region of Araruama, and will also contribute to microbiological studies of habitability conditions on Mars.