THE STUDY OF POTENTIAL EXOPLANET BIOSIGNATURES -- THE GLOBAL IMPACT OF LIFE ON A PLANETARY ENVIRONMENT -- HAS BEEN INFORMED PRIMARILY BY THE MODERN EARTH WITH LITTLE YET EXPLORED BEYOND ATMOSPHERIC O2 FROM OXYGENIC PHOTOSYNTHESIS AND ITS ACCOMPANYING PLANETARY SURFACE FEATURE THE VEGETATION RED EDGE REFLECTANCE. HOWEVER THESE BIOSIGNATURES HAVE ONLY BEEN PRESENT FOR LESS THAN HALF THE EARTH S HISTORY AND RECENT GEOCHEMICAL EVIDENCE SUGGESTS THAT ATMOSPHERIC O2 MAY HAVE BEEN AT VERY LOW - LIKELY UNDETECTABLE - LEVELS UNTIL 0.8 GA (PLANAVSKY ET AL. 2014). GIVEN THAT OUR PLANET WAS INHABITED FOR VERY LONG PERIODS PRIOR TO THE RISE OF OXYGEN AND THAT A SIMILAR PERIOD OF ANOXYGENIC LIFE MAY OCCUR ON EXOPLANETS MORE STUDIES ARE NEEDED TO CHARACTERIZE REMOTELY DETECTABLE BIOSIGNATURES ASSOCIATED WITH MORE EVOLUTIONARILY ANCIENT ANOXYGENIC PHOTOTROPHS. THE GOALS OF THIS PROPOSED MULTIDISCIPLINARY STUDY ARE TO MEASURE THE SURFACE REFLECTANCE SPECTRA OF ANOXYGENIC PHOTOTROPHS UNDERSTAND THE RULES THAT DICTATE THEIR SPECTRAL FEATURES SO THAT THEY CAN BE PREDICTED FOR EXOPLANETS AND ASSESS THEIR REMOTE DETECTABILITY AS A FUNCTION OF ENVIRONMENTAL CONTEXT ACROSS A RANGE OF SPATIAL SCALES: (1) LOCAL FIELD MEASUREMENTS OF ENVIRONMENTAL SAMPLES (2) REGIONAL ON MODERN EARTH (CONTINENTS AND OCEANS) USING AIRBORNE SENSORS AND EARTH-OBSERVING SATELLITES AND (3) PLANETARY-SCALE IN EXOPLANETARY DISK-AVERAGED SPECTRA UNDER VARIOUS ATMOSPHERES AND CLOUD COVERAGE LEVELS. OUR PRELIMINARY MEASUREMENTS SHOW THAT PURE CULTURES OF ANOXYGENIC PHOTOTROPHS PRODUCE NIR EDGE(S) IN THEIR SPECTRAL REFLECTANCE DUE TO ABSORPTION OF LIGHT BY BACTERIOCHLOROPHYLL (BCHL) PIGMENTS. WE ASSESSED THE DETECTABILITY OF THESE FEATURES ENVIRONMENTAL SAMPLES OF MICROBIAL MATS AND OBSERVED MULTIPLE NIR EDGES ASSOCIATED WITH EACH PIGMENT. WE INITIALLY EXPECTED ONLY TO DETECT THE ABSORPTION OF LIGHT BY THE PIGMENTS IN THE SURFACE LAYER OF THE MAT. SURPRISINGLY WE DETECTED CYANOBACTERIAL CHL A IN THE SURFACE LAYER AS WELL AS BCHL C AND BCHL A IN THE ANOXYGENIC UNDERLAYERS. THIS SUGGESTS THAT IT DOES NOT MATTER WHO S ON TOP AS WE WERE ABLE TO OBSERVE PIGMENTS THROUGH ALL MAT LAYERS DUE TO THEIR DIFFERENT ABSORPTION MAXIMA. THE PRESENCE OF MULTIPLE PIGMENTS AND THUS MULTIPLE NIR EDGES COULD SIGNIFY LAYERED PHOTOTROPHIC COMMUNITIES AND POSSIBLY STRENGTHEN SUPPORT FOR THE DETECTION OF A SURFACE EXOPLANET BIOSIGNATURE. IN GENERAL THE PROPOSED WORK WILL INFORM THE SEARCH FOR LIFE ON EXOPLANETS AT A SIMILAR STAGE OF EVOLUTION OR BIOGEOCHEMICAL STATE AS THE PRE-OXIC EARTH. THIS PROPOSAL SPEAKS TO THE EXOBIOLOGY SOLICITATION NNH15ZDA001N-EXO RESEARCH AREAS OF EARLY EVOLUTION OF LIFE AND THE BIOSPHERE AND BIOSIGNATURES AND LIFE ELSEWHERE. SPECIFICALLY THE PROPOSED RESEARCH WILL PROVIDE A NEW SUITE OF EXPERIMENTALLY MEASURED SURFACE SPECTRAL BIOSIGNATURES FOR REMOTE SENSING APPLICATIONS WHICH WILL AID IN THE INVESTIGATION OF THE DISTRIBUTION OF LIFE IN THE UNIVERSE.