The burden of proof for confirming the existence of life outside of our planet will be unprecedented in scientific history. Finding extraterrestrial microorganisms (whether fossil or extant) would provide the most direct evidence of life. Given planetary protection concerns, we are more likely to sample fossil microorganisms, but the biogenicity of ancient terrestrial microfossils is greatly debated owing to often poor preservation. Thus, other biosignatures are
typically required to establish the biogenicity of putative ancient microfossils and other microbial structures. By developing additional novel biosignatures and combining multiple techniques for establishing biogenicity, we can find evidence of life that is more convincing. Such techniques would provide invaluable tools for the search for extraterrestrial life. This session seeks to highlight work being done to develop novel biosignatures or to use established biosignatures to search for new evidence of early life on Earth and/or past or present
life on Mars.