We welcome Dr. Elisse Magnuson as a speaker for our SES Seminar series to talk about "Microbial life and activity in a Martian analogue". Dr. Magnuson is a postdoctoral researcher at the School of Environmental Sciences working with our own Dr. Jackie Goordial. 

Abstract

Life as we know it depends on liquid water. Recent evidence indicates that not only did ancient Mars once have a vast network of surface waters but that liquid water likely persists in the Martian subsurface to this day. Study of analogue environments, or environments with environmental conditions similar to those on ancient or extant Mars, provides insights into the potential life forms that could exist in on Mars and other worlds. Lost Hammer Spring, located on Axel Heiberg Island in the Canadian high Arctic, is one of the coldest and saltiest terrestrial springs discovered to date, the coldest known terrestrial methane seep, and a close analogue of putative Martian waters. It perennially discharges anoxic (<1 ppm dissolved oxygen), sub-zero (~−5 °C), and hypersaline (~24% salinity) brines from the subsurface through up to 600 m of permafrost. A multi-omics approach utilizing metagenome, metatranscriptome, and single-amplified genome sequencing revealed an active microbial community in the spring sediments utilizing primarily inorganic compounds (hydrogen sulfide, hydrogen, carbon dioxide) as energy and carbon sources, driven in part by sulfide-oxidizing bacteriascavenging trace oxygen. These results demonstrated Mars-relevant metabolisms including sulfide oxidation, sulfate reduction, anaerobic oxidation of methane, and oxidation of trace gases (hydrogen, carbon monoxide) detected under anoxic, hypersaline, and sub-zero ambient conditions, providing evidence that similar extant microbial life could potentially survive in similar habitats on Mars.

Bio

Elisse Magnuson is a postdoctoral scholar in the School of Environmental Sciences with Dr. Jackie Goordial. Her research examines microbial diversity and activity in extreme environments on Earth in order to explore the origin, potential, and limits of life on Earth and other worlds. She completed her M.A.Sc. in Applied Chemistry at the University of Toronto and Ph.D. in microbiology at McGill University, where she studied microbial communities in Martian analogue saline springs in the Canadian high Arctic. Her postdoctoral work focuses on the potential for microbial life and activity in the atmosphere.