Caption: 
Scientists have inferred that a soda or alkaline ocean (containing NaHCO3 and/or Na2CO3) inside of Enceladus interacts geochemically with a rocky core. Geochemical modeling and laboratory experiments indicate that this interaction promotes the dissolution of phosphate minerals, making phosphate (e.g., HPO4-2) readily available to potential life in the ocean. The discovery of phosphates by Cassini strongly supports the paradigm that Enceladus’ ocean is habitable.

Credit: 
Courtesy of SwRI