SALINE LAKES … A LOGICAL STEP IN EXPLORING HABITABILITY OF “THE FINAL FRONTIER”
Nicoll et al
Studies of modern biota in Earth's extreme environments provide valuable insights about microbial life as preserved in the rock record since the Archean (e.g., Knoll 1985; Brocks et al. 1999; Xiong et al. 2000; Eigenbrode and Freeman 2006; Kaufmann et al. 2007; Brake and Hasiotis 2008). Paradigms of evolutionary biology on Earth extend to astrobiology, a field that studies the origin, evolution and distribution of extraterrestrial life forms. The goal of space exploration in its pursuit to find life is to “follow the water” (NASA 2008). As such, the presence of “the universal solvent”—water—is key to assessing the habitability of Mars and other planets (e.g., Rothschild 1990; Malin and Edgett 2003; Squyres et al. 2004; Lineweaver et al. 2004; Bullock 2005).
Many recent publications present telescope and space probe data as evidence for the presence of watery biomes in our solar system, and beyond. Life possibly existed in the paleowater body at Endeavour Crater, Mars (Arvidson et al. 2014). Saltwater oceans hypothetically exist below the ice on the Saturn moon Enceladus (e.g., Postberg et al. 2009, 2011). On Europa, the innermost icy satellite of Jupiter, potential biomes include brines made of liquid hypersaline waters in the shallow subsurface crust (Schmidt et al. 2011; Roth et al. 2013). These discoveries invigorate speculation about what microbes might be present in these extreme environments.