Exploring the inner complexity of Enceladus

Subsurface ocean composition hints at habitable conditions.

US researchers say a new geochemical model reveals that carbon dioxide from Saturn’s moon Enceladus may be controlled by chemical reactions at its seafloor.

Studying the plume of gases and frozen sea spray released through cracks in the moon’s icy surface suggests an interior more complex than previously thought, according to their paper in Geophysical Research Letters.

Analysis of mass spectrometry data from NASA’S Cassini spacecraft indicates that the abundance of CO2 is best explained by geochemical reactions between the

Moon’s rocky core and liquid water from its subsurface ocean.

Integrating this information with previous discoveries of silica and molecular hydrogen points to a more complex, geochemically diverse core.

“Based on our findings, Enceladus appears to demonstrate a massive carbon sequestration experiment,” says lead author Christopher Glein, from Southwest Research Institute (SWRI), Texas. “On Earth, climate scientists are exploring whether a similar process can be utilised to mitigate industrial emissions of CO2.

“Using two different data sets, we derived CO2 concentration ranges that are intriguingly similar to what would be expected from the dissolution and formation of certain mixtures of silicon- and carbon-bearing minerals at the seafloor.”

Adding to this complexity, the researchers say, is the likely presence of hydrothermal vents inside Enceladus. At Earth’s ocean floor, hydrothermal vents emit hot, energy-rich, mineral-laden fluids that allow unique ecosystems teeming with unusual creatures to thrive.

“While we have not found evidence of the presence of microbial life in the ocean of Enceladus, the growing evidence for chemical disequilibrium offers a tantalising hint that habitable conditions could exist beneath the moon’s icy crust,” says SWRI’S Hunter Waite.