Fluid and mineral carbonate biogeochemistry and microbial mats of Caribou Plateau alkaline lakes

Date

2024

Authors

Thompson, Maya

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Abstract

Alkaliphilic microbial mats are the biological foundation in Interior British Columbia alkaline lakes. They are also associated with rare and hard-to-form carbonates that precipitate within the mat laminae. When analyzed with SEM, rounded mineral nodules and crystals were found growing along the length of fibrous microbial mat algaes. Mg-Ca minerals were also found on encrusted soil samples taken along the lacustrine shore. The storage of microbial mats in 90% EtOH shined a light on the importance of organic solvents in the precipitation of hard-to-form carbonates, as these samples were found to precipitate out Mg-Ca and Mg-Na minerals more readily than samples stored in other solutions. The changes in water samples combined with microenvironments created near cell walls suggest that a combination of high alkalinity and biological activities control the precipitation of hard-to-form carbonates. We seek to investigate the functions of microbial mats from a geologist’s perspective and to couple it with in-lab experimentation and analysis, and computational modeling. Supervisor: Anne-Sofie Ahm

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Keywords

alkaline lake, microbially mediated precipitation, biogeochemistry, Mg-carbonate, alkaliphile

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