THIS PROPOSAL SEEKS TO DEVELOP A COMPREHENSIVE UNDERSTANDING OF A HYPERSALINE MARS ANALOG ENVIRONMENT ADDRESSING THE CENTRAL QUESTION: WHAT TYPES OF BIOSIGNATURES FORM AND ARE PRESERVED OVER TIME? WE ARE ADDRESSING THIS QUESTION SPECIFICALLY IN A MAGNESIUM SULFATE DOMINATED SYSTEM AS SULFATE SALTS HAVE BEEN WIDELY DOCUMENTED ON MARS BUT ARE NOT THE DOMINANT TYPE HERE ON EARTH. AS SUCH AN UNDERSTANDING OF THE PRESERVATION POTENTIAL OF THESE TYPES OF SALTS OVER TRADITIONAL SODIUM CHLORIDE ENVIRONMENTS IS LACKING IN THE LITERATURE. FURTHERMORE THE COMMUNITY COMPOSITION WILL DIFFER FROM TRADITIONAL HYPERSALINE ENVIRONMENTS LEADING TO A DIFFERENT SET OF BIOSIGNATURES BEING PRESENT. THIS PROPOSAL WILL FOCUS ON UNDERSTANDING FOUR DIFFERENT BIOSIGNATURES EACH WITH VARYING RESIDENCY TIMES IN THE GEOLOGIC RECORD: DNA AMINO ACIDS LIPIDS AND SULFUR ISOTOPIC FRACTIONATION SIGNATURES. SALT HAS A DOCUMENTED ABILITY TO PRESERVE BIOLOGICAL MOLECULES OVER LONGER TIMESCALES THAN NON-SALINE ENVIRONMENTS AND WHOLE CELLS HAVE BEEN PRESERVED IN A VIABLE STATE WITHIN FLUID INCLUSIONS ON THE ORDER OF THOUSANDS OF YEARS. THIS WORK IS DIRECTLY RELEVANT TO THE BIOSIGNATURES AND LIFE ELSEWHERE EXOBIOLOGY PROGRAM THEME AS IT FOCUSES ON FACTORS INFLUENCING BOTH GENERATION AND DETECTION OF SPECTROSCOPIC AND MORPHOLOGICAL BIOSIGNATURES ASSOCIATED WITH HYPERSALINE ENVIRONMENTS. FOR THE REMAINDER OF THIS AWARD THE PI WILL BE BASED AT GEORGETOWN WHERE THEY WILL CONDUCT A FULL METAGENOMIC SURVEY OF THE HYPERSALINE ENVIRONMENT AND FOCUS SPECIFICALLY ON THE PRESENCE AND DEGRADATION OF DNA AMINO ACIDS AND ATP WITHIN THE SYSTEM AS WELL AS THE POTENTIAL AFFECTS OF HYPERSALINITY ON SULFUR ISTOPE FRACTIONATION. SPECIFICALLY PI PONTEFRACT WILL BE RESPONSIBLE FOR LEADING THE METAGENOMIC ANALYSES THE DEGRADATION ANALYSES OF AMINO ACIDS AND ATP AS WELL AS THE SULFUR ISOTOPE WORK.