Observations of Mars have revealed the widespread presence of paleo-evaporitic deposits, in the form of magnesium sulfate salts. MgSO₄ salts have been known to preserve evidence of life on geological timescales, which makes its discovery beyond Earth of interest to the Astrobiological community. Salts have important implications for biology, as they largely determine the water activity (a_w) of a given system, and can be either kosmotropic (stabilizing) or chaotropic (destabilizing) to biological molecules – thus having important implications for habitability, and preservation of putative biosignatures. The Interior Plateau of British Columbia is host to a unique set of MgSO₄-dominated lakes, which owe their composition to the regional geology. Many of these ephemeral endorheic lakes appear “spotted”, where sub-basins form within the lake margins that are spatially stable over time. I will present data addressing the role that sulfate and magnesium ions – frequently present in excess of 3 M – have in the composition of present-day microbial communities in these systems, and ultimately, discuss how these systems preserve and degrade various biosignatures over time.

Speaker: Alexandra Pontefract (Johns Hopkins University Applied Physics Laboratory)

Talks are held in the STScI John N. Bahcall Auditorium. Light lunch (provided) starts at 12pm; talk starts at 12:30pm.

Planets, Life, and the Universe Lecture Series presentations are also webcast live. Webcasts can be viewed at the STScI webcast site during the scheduled presentation, and can be found afterward in the STScI webcast archive.

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