HYPERSALINE ENVIRONMENTS ARE CHEMICALLY DIVERSE SYSTEMS THAT ARE HOST TO ORGANISMS IN ALL DOMAINS OF LIFE MANY WITH UNIQUE ADAPTATIONS FOR SURVIVAL UNDER EXTREME CONDITIONS. SALTS HAVE LONG BEEN DOCUMENTED AS BEING CAPABLE OF PRESERVING A RICH RECORD OF BIOLOGICAL PROCESSES HAVING OBVIOUS ASTROBIOLOGICAL IMPLICATIONS FOR THE SEARCH FOR LIFE BEYOND EARTH: OBSERVATIONS OF MARS HAVE REVEALED THE EXISTENCE OF EPHEMERAL PALEOLAKES REPRESENTED BY WIDESPREAD DEPOSITS OF SULFATE SALTS AND THERE IS SIGNIFICANT EVIDENCE FOR THE PRESENCE OF MGSO4 OCEANS ON EUROPA. MUCH OF THE WORK INTO BIOSIGNATURE PRESERVATION IN HYPERSALINE ENVIRONMENTS ON EARTH HOWEVER HAS FOCUSED ON NACL-RICH SYSTEMS OWING TO THE DOMINANCE OF THIS SALT TYPE. MGSO4 SYSTEMS ALTERNATIVELY ARE OF INTEREST GIVEN THE STABILIZING NATURE OF THE SULFATE ANION FOR BIOLOGICAL MOLECULES. ONGOING INVESTIGATIONS INTO A RANGE OF SULFATE DEPOSITS HAVE REVEALED THE PRESERVATION OF DNA AMINO ACIDS AND CELLS ON TIMESCALES OF THOUSANDS TO MILLIONS OF YEARS. HERE WE INVESTIGATE THE SULFATE-DOMINATED SYSTEMS OF THE BASQUE LAKES AND CLINTON LAKE IN BRITISH COLUMBIA CANADA AND EXPLORE THE PRESERVATION POTENTIAL OF THESE SALTS FOR (GEOLOGICALLY-SPEAKING) SHORT-TERM AND LONG-TERM BIOSIGNATURES. THIS WORK WILL EXPLORE THE INTERACTIONS BETWEEN SALTS AND BIOLOGICAL MOLECULES AND INFORM THE SEARCH FOR LIFE IN THESE IMPORTANT HYPERSALINE ENVIRONMENTS. THIS BUILDS ON WORK THAT THE PI HAS PREVIOUSLY CONDUCTED AT SPOTTED LAKE IN BC. GOALS AND OBJECTIVES: 1. CONSTRAIN THE EFFECT OF PHYSICOCHEMISTRY ON HABITABILITY IN MGSO4 ENVIRONMENTS: HABITABILITY IN THESE SYSTEMS CAN BE QUALIFIED THROUGH A MEASUREMENT OF WATER ACTIVITY BUT THIS METRIC ALONE DOES NOT CONVEY THE COMPLEX EFFECTS THAT SALT TYPE CONCENTRATION AND IONIC CHARGE HAVE ON THE HABITABILITY OF A SYSTEM. TO ELUCIDATE THIS COMPLEXITY WE WILL CONDUCT STANDARD GEOCHEMICAL MEASUREMENTS ALONG WITH WATER ACTIVITY CHAOTROPIC (DESTABILIZING EFFECTS) AND IONIC STRENGTH CALCULATIONS. 2. CHARACTERIZE THE MICROBIAL COMMUNITY IN EACH EPHEMERAL LAKE ENVIRONMENT: WE WILL CONDUCT METAGENOMIC ANALYSES USING BOTH ILLUMINA AND NANOPORE SEQUENCING TO ELUCIDATE THE MICROBIAL COMMUNITIES WITHIN THE SALT CRUSTS WATER COLUMN AND SOILS. WE WILL ALSO SEQUENCE FROM THE COLLECTED CORES TO UNDERSTAND HOW THESE COMMUNITIES ARE CHANGING WITH DEPTH. THIS DATA WILL THEN BE LINKED TO THE BIOSIGNATURES THAT WE IDENTIFY.