Aliens in the Arctic

The search for life on our solar system’s planets and moons is in its infancy. Although physical and geochemical properties of these bodies can be measured by orbiting spacecraft and landers these platforms are not yet sophisticated enough for life detection. Because of this evaluating the potential for extraterrestrial life relies on detailed investigations of analogous environments on Earth. In the case of Jupiter’s moon Europa, whose icy shell may hide a life-bearing ocean, an analogous environment can be found within Arctic multiyear sea ice, ice that has persisted through several complete seasonal cycles. By investigating how brine pore spaces within this ice evolve, and how microbial communities may be structured in response, we gain some understanding of how a microbial ecosystem within Europa’s icy shell might be structured. Applying equations for calculating sea ice brine volume and brine channel connectivity to the Europan ice shell allows for an estimation of where Europa’s ice shell become connective, and thus where a continual microbial ecosystem might be found. Although this estimate will need modification as our understanding of the ionic composition of Europa’s ice shell increases, if life exists on Europa a continual microbial community could be found within 12 km of the surface.