Phosphate, a key building block of life, found on Saturn’s moon Enceladus

An artist’s rendition of Saturn’s moon Enceladus depicts hydrothermal activity on the seafloor and cracks in the moon’s icy crust that allow material from the watery interior to be ejected into space.

An international team including a University of Washington scientist has found that the water on one of Saturn’s moons harbors phosphates, a key building block of life. The team led by the Freie Universität Berlin used data from NASA’s Cassini space mission to detect evidence of phosphates in particles ejected from the ice-covered global ocean of Saturn’s moon Enceladus.

Phosphorus, in the form of phosphates, is vital for all life on Earth. It forms the backbone of DNA and is part of cell membranes and bones. The new study, published June 14 in Nature, is the first to report direct evidence of phosphorus on an extraterrestrial ocean world.

The team found that phosphate is present in Enceladus’ ocean at levels at least 100 times higher — and perhaps a thousand times higher — than in Earth’s oceans.

“By determining such high phosphate concentrations readily available in Enceladus’ ocean, we have now satisfied what is generally considered one of the strictest requirements in establishing whether celestial bodies are habitable,” said third author Fabian Klenner, a UW postdoctoral researcher in Earth and Space Sciences. While at Freie Universität Berlin, Klenner did experiments that revealed the high phosphate concentrations present in Enceladus’ ocean.