Probing The Habitability Of Potential Sulfuric Acid Rich Subsurface Lakes In Europa’s Ice Shell Via Saci/STIV Integrated Models
Experimentally modeling the habitability of extreme ocean world conditions, such as those on Jupiter’s moon: Europa, would benefit from integrated microbe-virus model studies to provide both a microbial model and a virus capable of nutrient cycling.
This work experimentally probes the microbe/virus combination Saci/STIV as a potential microbial model for habitability studies of Europa’s ice-ocean interface in subsurface lakes with implications for habitats with extreme conditions and fluid mixing.
This study experimentally modeled archaea/virus-integrated systems in one set of conditions that fall within the range of currently proposed for subsurface lakes in Europa’s ice shell: 3.5% salinity, pH 3, rich in Na+/Fe2+/Mg2+/ SO 2−4 /H+, fluctuating dissolved oxygen (D.O.), and 1–2°C to explore habitability limits and candidate biosignatures. Planktonic Sulfolobus acidocaldarius (Saci) lysogens of Sulfolobus Turreted Icosahedral Virus (STIV) were included for the determination of potential habitability and biosignatures in both models.
Extensive biofilm formation, biosulfur detection via Raman spectroscopy, viral mRNA/protein detection by RT-qPCR and western blotting, and successful viability assays under these conditions support the potential habitability under Europa-analog conditions. Cold-adapted Saci developed extensive biofilm rich in biosulfur globules, suggesting the possibility of sulfur-oxidizing metabolism.
Finally, biosulfur and viral major capsid proteins (MCPs), with inter-domain conserved double jelly roll morphologies, were identified as candidate biosignatures for life on acidic icy ocean worlds. Such cryotolerant strains and the viral proteins proliferated from them may have applications in astrobiology, but also for extreme microbiology and beyond.
Potential Habitability Model of Europa’s ocean and ice shell. — FRONTIERS
Astrobiology,
