Beyond the Calcium chloride Brine Transient Microbial Communities at the Edge of Habitability in Don Juan Pond, McMurdo Dry Valleys, Antarctica
This study investigates the microbial diversity and ecological organization of transient meltwater habitats associated with Don Juan Pond (DJP), one of the most extreme CaCl2-rich environments on Earth, located in the McMurdo Dry Valleys, Antarctica. Samples were collected from ephemeral streams, shallow ponds, sediments, ice and the central brine during two Antarctic field campaigns conducted between 2021 and 2023. Microbial communities were characterized using high-throughput amplicon sequencing targeting the 16S rRNA gene (prokaryotes), the 18S rRNA gene (microeukaryotes) and the ITS region (fungi). The project investigates how hydrochemical gradients, seasonal hydrological dynamics and microbial interactions shape community composition in polyextreme environments. These datasets provide a comprehensive characterization of bacterial, archaeal, fungal and microeukaryotic diversity inhabiting transient habitats surrounding Don Juan Pond and contribute to understanding the ecological limits of life in Antarctic deserts and other extreme saline environments.