The primary aim of this review is to highlight that sea-ice microbes would be capable of occupying ice-associated biological niches on Europa and Enceladus. These moons are compelling targets for astrobiological exploration because of the inferred presence of subsurface oceans that have persisted over geological timescales. Although potentially hostile to life in general, Europa and Enceladus may still harbour biologically permissive domains associated with the ice, ocean and seafloor environments. However, validating sources of free energy is challenging, as is qualifying possible metabolic processes or ecosystem dynamics. Here, the capacity for biological adaptation exhibited by microorganisms that inhabit sea ice is reviewed. These ecosystems are among the most relevant Earth-based analogues for considering life on ocean worlds because microorganisms must adapt to multiple physicochemical extremes. In future, these organisms will likely play a significant role in defining the constraints on habitability beyond Earth and developing a mechanistic framework that contrasts the limits of Earth's biosphere with extra-terrestrial environments of interest.

Item Type:	Refereed Article
Keywords:	astrobiology, extremophiles, microorganisms, sea ice, ocean worlds
Research Division:	Biological Sciences
Research Group:	Microbiology
Research Field:	Microbial ecology
Objective Division:	Expanding Knowledge
Objective Group:	Expanding knowledge
Objective Field:	Expanding knowledge in the biological sciences
UTAS Author:	Martin, A (Dr Andrew Martin)
UTAS Author:	McMinn, A (Professor Andrew McMinn)
ID Code:	116492
Year Published:	2018 (online first 2017)
Web of Science® Times Cited:	29
Deposited By:	Ecology and Biodiversity
Deposited On:	2017-05-11
Last Modified:	2018-05-28
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