Potential Influence of Perchlorate on Organic Carbon in Martian Regolith

Abstract:

Perchlorate is a strong oxidizer present at elevated concentrations in surface martian regolith. Chemical and isotopic modification of potential organic carbon with perchlorate in martian regolith during H₂O_(l) interactions is unknown. Here we assess the relationship between martian levels of perchlorate and organic carbon present in life harbouring geologic material from Earth. These materials represent chemical (i.e., processed serpentine soils from Sri Lanka) and temperature (i.e., hydrothermal jarosite/goethite deposit from White Island, New Zealand) extremes to where life exists on Earth. Preliminary evidence demonstrates that organic carbon decreases and δ¹³C values are modified for ultramafic sediment in both perchlorate kinetic and incubation experiments. In hydrothermal jarosite/goethite with microbial communities present, total and organic carbon is maintained and little modification in δ¹³C values is apparent. These preliminary results suggest that surface hydrothermal deposits with mineralogically ‘protected’ organic carbon are preferable sites to assess the potential of life on Mars.