Title: Alien oceans: hot springs, phosphorus, and the search for life in the solar system

Abstract: The discovery of liquid water oceans on Saturn’s moon Enceladus in 2006 and as many as a dozen other moons in the solar system (most notably Jupiter’s moon Europa) has greatly changed our understanding of our solar system’s ‘habitable zone’. Rather than simply searching for liquid water, planetary scientists now need a framework to assess the relative likelihood of different planetary targets to host the physical and chemical ingredients required to support detectable biology. In this talk, I will discuss the planetary (hydrothermal) and exogenous (meteoritic sedimentation) processes leading to nutrients and bioavailable energy on ocean moons. I show how even a relatively tectonically quiescent seafloor can lead to hydrothermal circulation. I will then focus on a specific bioessential nutrient produced by this circulation– phosphorus which was recently discovered on Enceladus. Our published results anticipated those observations to within analytical error of the satellite. I show how models integrating stellar stoichiometry and an understanding of thermodynamics and fluid dynamics can lead to testable predictions of icy moon ocean chemistry. Finally, I discuss the implications for exoplanet and future planetary science missions.