Signatures of abiotic organic matter and its processing: Implications for the detection of biosignatures

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Understanding how life originated on Earth and whether it may have arisen elsewhere in the Universe are the most fundamental questions we can ask, but they are also the most daunting. Nonetheless, progress is being made that is increasing our understanding of how we might answer them. Central to these questions is the ability to identify signatures of life, "biosignatures", and to differentiate them from signatures of abiotic processes, "abiosignatures". Biosignatures of life include recognizable organic molecules, isotopic ratios and mineral compositions, and patterns therein that can be unambiguously attributed to life. These biosignatures must be differentiated from patterns in these same parameters that existed prior to the advent of life, when only abiotic processes were operating. This understanding is all the more necessary as we continue to expand our interest in searching for evidence of life beyond the Earth. We need to interpret new observations including the detection of organic molecules on Mars by the Curiosity rover, the results of the ongoing Hyabusa 2 and OSIRIS Rex missions to asteroids, the planned Mars 2020 and ExoMars missions to Mars that include proposed sample return, and the proposed explorations of the moons of Saturn and Jupiter. This research proposal will continue my research program that seeks to further our understanding of biosignatures and abiosignatures with a much stronger emphasis on abiosignatures. It will further develop newly established collaborations with the Royal Ontario Museum (ROM) that brings an organic geochemistry perspective to their ongoing work characterizing and investigating meteorites. This will include analysis of the ROMs samples of the uniquely pristine and carbon rich Tagish Lake meteorite as well as analysis of meteorites from North West Africa which have yet to be characterized. The samples will be selected to provide insights into the amounts and signatures of organic matter that was delivered to the prebiotic Earth and thus supported the advent of life. Complimentary to the meteorite analyses, this research program will continue my investigation of microbial communities in the Earth's subsurface. It will seek to assess the extent to which we can identify biosignatures of microbial communities in the presence of abiosignatures of organic compounds produced via water-rock interaction. Finally, the stability of both biosignatures and abiosignatures will also be addressed via experimental studies of organic compound stability in the planetary simulators at McMaster and York Universities. These facilities allow the impact of changes in temperature, humidity, UV flux and atmospheric composition on the preservation, or potentially on the production, of organic compounds to be assessed. This research program will increase our ability to recognize abiosignatures and biosignatures and concurrently provide insight into the organic compounds that supported the advent of life.