Polar Research: November 2008

Jennifer Eigenbrode: Ice is a cryogenic vault for preserving organics and other materials that may record planetary processes. On Earth, cold temperatures retard against hydrolysis and oxidation, which degrade biomolecules and other organics, allowing traces of life to persist in the presence of impurities. We are exploring the dilute biological and organic inventory contained within modern glacial ice on Earth in order to understand the habitat of microorganisms in near-surface glacial ice and to distinguish allochthonous from autochthonous organic records.

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.