Abstract

Enceladus, a small icy satellite of Saturn, was found to have a subsurface water ocean and evidence of ongoing hydrothermal activity in the seafloor. The ocean water, sampled via the polar plume, was inferred to contain substantial levels of inorganic and organic carbon as well as ammonia. However, there are very few constraints on the availability of other bio-essential nutrients, including phosphorus, sulfur, iron, and other enzyme-supporting metals, as well as biomolecules. This talk will summarize our current understanding and report some ongoing research about the availability of these nutrients and biomolecules. Furthermore, I will overview the limiting nutrient and possibly additional limiting factors for the origin and survival of life in the subsurface oceans of some icy moons. These considerations can help in defining future astrobiology missions to the outer solar system and beyond.