Phosphates detected in the plume material of Saturn's moon Enceladus could indicate phosphorus chemistry occurring in its subsurface ocean. Here we discuss the production of organophosphates, reduced phosphorus compounds, and polyphosphates that might be possible within Enceladus and how this could lead to potential prebiotic chemistry. (Image: NASA).

Abstract

Phosphorus (P) is a limiting element for prebiotic/biotic activity, and its availability constrains planetary habitability. Phosphates detected in Enceladus’ plume material could expand the range of potential prebiotic reactions possibly occurring within its subsurface ocean. However, for phosphorus chemistry to influence potential prebiotic chemistry, the environment must be favorable for the production of organophosphates and condensed phosphorus species. While mechanisms for the formation of organophosphates and polyphosphates exist within an early Earth context, these reactions rely on various environmental sources of phosphorus and are typically dependent on a low water activity environment to drive condensation or phosphorylation. For Enceladus, this would limit such reactions to within the core and/or hydrothermal systems, and water-rock chemistry in Enceladus’ core would be the singular source for oceanic phosphorus for prebiotic chemistry. Here we discuss the production of organophosphates, reduced P compounds, and polyphosphates that might be possible within Enceladus, based on our understanding of prebiotic phosphorus reactions on early Earth.