An Arctic Analog to Europa: Signs of Life on the Ice

Damhnait Gleeson: Borup Fiord Pass, located on the Canadian Arctic Island of Ellesmere, represents the only known site on Earth where sulfur minerals and glacial ice are found in intimate association. Spring waters access the surface of the ice during the melt season each year, depositing elemental sulfur, gypsum and calcite and exsolving H2S. The sulfur signature of the spring deposits is extensive enough to be detected and monitored from orbital satellite observations and an autonomous onboard classifier can provide temporal coverage of spring activity. Diverse microbial communities are active within the deposits and are mediating the geochemistry of the deposits by the sulfur redox transformations from which they gain energy. Cultivation experiments targeting sulfide-oxidizing members of the microbial community have isolated microorganisms from the spring deposits which are producing biomineralized sulfur structures in culture.

Borup Fiord Pass represents the closest terrestrial analog for near-term exploration of the icy surface of Europa, providing us with the opportunity to investigate sulfur-on-ice mineralogy in the field for the first time and gain understanding of how the spectral signatures of these kinds of materials vary from field to orbital scales. Microorganisms present at the site are cycling sulfur through different redox states in this cold environment, and the geochemical macrosignature of the springs and their associated deposits is being influenced as a result of metabolic activities of the microcommunity. This work informs the search for biosignatures at icy moons like Europa.

For more information and participation instructions: http://astrobiology.nasa.gov/event/extreme-life-seminar/

The November Forum for Astrobiology Research (FAR) will be held on Monday, November 17th at 11:00am PT (9:00am HT, 12:00pm MT, 1:00pm CT, 2:00pm ET). This seminar is broadcast live by NAI – you can attend locally from a videoconferencing room or from your desktop (see instructions below). Please join us to hear presentations on “Extreme Environments” by Jennifer Eigenbrode of Goddard Space Flight Center and Damhnait Gleeson University of Colorado at Boulder and JPL.

Source: NAI Newsletter