Habitability and Potential Biosignatures of Psychrophilic Microorganisms on Europa and Enceladus

Jupiter’s and Saturn’s satellites, Europa and Enceladus, respectively, are known for their ice crusts and subsurface oceans, which, as some scientists hypothesise, may harbour life, due to the thermal conditions in which some of the terrestrial organisms are able to thrive. These microorganisms are called psychrophiles, and they can live in temperatures from -20 to 10°C. The goal of this scientific paper was to test this hypothesis by comparing psychrophiles on Europa and Enceladus using 6 characteristics: temperature, habitats, oxygen, pH, energy sources, and metabolism. The results show that, though terrestrial psychrophiles might not be able to tolerate some of the pH levels of their oceans, all the other characteristics substantially overlap, which implies that Europa and Enceladus have a possibility to be habitable. This paper also discusses how methods such as mass spectrometry, fluorescence/reflectance spectroscopy, and gas chromatography can be used for detecting the biosignatures of psychrophiles, including breakdown products of biological molecules, microfossils, gases excreted by organisms, pigments, and complex organics. All of the above-mentioned suggest that extraterrestrial psychrophiles may indeed have a non-zero chance to exist on these moons due to their habitability, indicating that future astrobiological research should be directed in this direction.