Biosignature Molecules Accumulate and Persist in Evaporitic Brines: Implications for Planetary Exploration.

The abundance of potentially habitable hypersaline environments in our solar system compels us to understand the impacts of high-salt matrices and brine dynamics on biosignature detection efforts. We identified and quantified organic compounds in brines from South Bay Salt Works (SBSW), where evapoconcentration of ocean water enables exploration of the impact of NaCl- and MgCl-dominated brines on the detection of potential biosignature molecules. In SBSW, organic biosignature abundance and distribution are likely influenced by evapoconcentration, osmolyte accumulation, and preservation effects.

Single-cell analysis in hypersaline brines predicts a water-activity limit of microbial anabolic activity.

Hypersaline brines provide excellent opportunities to study extreme microbial life. Here, we investigated anabolic activity in nearly 6000 individual cells from solar saltern sites with water activities () ranging from 0.982 to 0.

The Bioburden and Ionic Composition of Hypersaline Lake Ices: Novel Habitats on Earth and Their Astrobiological Implications.

We present thermophysical, biological, and chemical observations of ice and brine samples from five compositionally diverse hypersaline lakes in British Columbia's interior plateau. Possessing a spectrum of magnesium, sodium, sulfate, carbonate, and chloride salts, these low-temperature high-salinity lakes are analogs for planetary ice-brine environments, including the ice shells of Europa and Enceladus and ice-brine systems on Mars. As such, understanding the thermodynamics and biogeochemistry of these systems can provide insights into the evolution, habitability, and detectability of high-priority astrobiology targets.

Microbial diversity and activity in Southern California salterns and bitterns: analogues for remnant ocean worlds.

Concurrent osmotic and chaotropic stress make MgCl -rich brines extremely inhospitable environments. Understanding the limits of life in these brines is essential to the search for extraterrestrial life on contemporary and relict ocean worlds, like Mars, which could host similar environments. We sequenced environmental 16S rRNA genes and quantified microbial activity across a broad range of salinity and chaotropicity at a Mars-analogue salt harvesting facility in Southern California, where seawater is evaporated in a series of ponds ranging from kosmotropic NaCl brines to highly chaotropic MgCl brines.

Current state of athalassohaline deep-sea hypersaline anoxic basin research-recommendations for future work and relevance to astrobiology.

Deep-sea hypersaline anoxic basins (DHABs) are uniquely stratified polyextreme environments generally found in enclosed seas. These environments select for elusive and widely uncharacterized microbes that may be living below the currently recognized window of life on Earth. Still, there is strong evidence of highly specialized active microbial communities in the Kryos, Discovery, and Hephaestus basins located in the Eastern Mediterranean Sea; the only known athalassohaline DHABs.

Microbial Life in Impact Craters.

Asteroid and comet impacts are known to have caused profound disruption to multicellular life, yet their influence on habitats for microorganisms, which comprise the majority of Earth's biomass, is less well understood. Of particular interest are geological changes in the target lithology at and near the point of impact that can persist for billions of years. Deep subsurface and surface-dwelling microorganisms are shown to gain advantages from impact-induced fracturing of rocks.

Sequencing nothing: Exploring failure modes of nanopore sensing and implications for life detection.

The detection of extant life is a major focus of many planned future planetary missions, a current challenge of which is the ability to target biomarkers capable of providing unambiguous evidence of life. DNA sequencing is increasingly recognized as a powerful tool for life detection for planetary exploration missions; beyond use of sequence information to determine the origins of the sample (e.g.

Characterization of Microbial Communities Hosted in Quartzofeldspathic and Serpentinite Lithologies in Jeffrey Mine, Canada.

The microbial ecology and activity of serpentine deposits and associated hydrated minerals are largely unknown. Previous research has largely focused on microbial communities in active serpentinizing systems, whereas relatively little research has demonstrated the ability of serpentine deposits to host microbial communities after the cessation of serpentinization. Given the potential role of serpentinization reactions fueling primitive microbial metabolisms on early Earth and the identification of serpentine deposits on Mars, knowledge of these geobiological relationships and potential for serpentine to host extant microbial communities and preserve biosignatures is increasingly important for planetary exploration seeking signs of life.

Microbial Diversity in a Hypersaline Sulfate Lake: A Terrestrial Analog of Ancient Mars.

Life can persist under severe osmotic stress and low water activity in hypersaline environments. On Mars, evidence for the past presence of saline bodies of water is prevalent and resulted in the widespread deposition of sulfate and chloride salts. Here we investigate Spotted Lake (British Columbia, Canada), a hypersaline lake with extreme (>3 M) levels of sulfate salts as an exemplar of the conditions thought to be associated with ancient Mars.

Microbial Diversity of Impact-Generated Habitats.

Impact-generated lithologies have recently been identified as viable and important microbial habitats, especially within cold and arid regions such as the polar deserts on Earth. These unique habitats provide protection from environmental stressors, such as freeze-thaw events, desiccation, and UV radiation, and act to trap aerially deposited detritus within the fissures and pore spaces, providing necessary nutrients for endoliths. This study provides the first culture-independent analysis of the microbial community structure within impact-generated lithologies in a Mars analog environment, involving the analysis of 44,534 16S rRNA sequences from an assemblage of 21 rock samples that comprises three shock metamorphism categories.