Frank Postberg; Yasuhito Sekine; Fabian Klenner; Christopher R. Glein; Zenghui Zou; Bernd Abel; Kento Furuya; Jon K. Hillier; Nozair Khawaja; S. Kempf; Lenz Noelle; Takuya Saito; J. Schmidt; Takazo Shibuya; R. Srama; Shuya Tan · 2023 · Nature
Paper
Abstract Saturn’s moon Enceladus harbours a global 1 ice-covered water ocean 2,3. The Cassini spacecraft investigated the composition of the ocean by analysis of material ejected into space by the moon’s cryovolcanic plume 4–9. The analysis of salt-rich ice grains by Cassini’s Cosmic Dust Analyzer 10 enabled inference of major solutes in the ocean water (Na +, K +, Cl –, HCO 3 –, CO 3 2– ) and its alkaline pH 3,11. Phosphorus, the least abundant of the bio-essential elements 12–14, has not yet been detected in an ocean beyond Earth. Earlier geochemical modelling studies suggest that phosphate might be scarce in the ocean of Enceladus and other icy ocean worlds 15,16. However, more recent modelling of mineral solubilities in Enceladus’s ocean indicates that phosphate could be relatively abundant 17. Here we present Cassini’s Cosmic Dust Analyzer mass spectra of ice grains emitted by Enceladus that show the presence of sodium phosphates. Our observational results, together with laboratory analogue experiments, suggest that phosphorus is readily available in Enceladus’s ocean in the form of orthophosphates, with phosphorus concentrations at least 100-fold higher in the moon’s plume-forming ocean waters than in Earth’s oceans. Furthermore, geochemical experiments and modelling demonstrate that such high phosphate abundances could be achieved in Enceladus and possibly in other icy ocean worlds beyond the primordial CO 2 snowline, either at the cold seafloor or in hydrothermal environments with moderate temperatures. In both cases the main driver is probably the higher solubility of calcium phosphate minerals compared with calcium carbonate in moderately alkaline solutions rich in carbonate or bicarbonate ions.
Analysis
This paper reports the first detection of phosphates in the ocean of Saturn's moon Enceladus, suggesting significantly higher phosphorus concentrations than in Earth's oceans.
Discovery
Bastien Bodin; Daniel Cordier; Ashley Gerard Davies
Kurt D. Retherford; Philippa M. Molyneux; Thomas K. Greathouse; Michael W. Davis; G. Randall Gladstone; Steven C. Persyn; Maarten H. Versteeg; Mary F. Araujo; Fran Bagenal; Tracy M. Becker; Arnaud Beth; Ronald K. Black; Bertrand Bonfond; Shawn M. Brooks; Emma J. Bunce; Alain Carapelle; Steven Cortinas; Gregory J. Dirks; Bryan Esquivel; Paul D. Feldman; Sue Ferrell; Mark Ferris; Leigh N. Fletcher; Matthew A. Freeman; Marina Galand; Rohini S. Giles; Denis Grodent; Vincent Hue; Erica Johnson; Joshua A. Kammer; Cynthia Kempe; Laurent Lamy; Adrian Martin; Melissa A. McGrath; Edward G. Nerney; Carlos Nuñez; Zachary Olsen; Norman Pelletier; Brandon Perez; Kristian B. Persson; Eric Quémerais; Rick Raffanti; Ujjwal Raut; Ryan Rickerson; Lorenz Roth; Oswald H. W. Siegmund; John R. Spencer; Andrew J. Steffl; Bradley J. Trantham; John V. Vallerga; Todd J. Veach; Michael A. Velez; Brandon C. Walther; the JUICE-UVS Team
Nancy Y. Kiang; Christopher Gisriel; Robert E. Blankenship; Mary N. Parenteau; Hazel A. Barton; Oded Béjà; Anthony J. Burnetti; Ligia F. Coelho; Saleheh Ebadirad; Nathan M. Ennist; Yuka Fujii; Colin Gates; R. J. Graham; Keiichi Inoue; Betül Kaçar; Yu Komatsu; Émilie A. Laflèche; Nicoletta La Rocca; Elisabetta Liistro; Jonathan Lindsey; Timothy Lyons; Carolina A. Martinez-Gutierrez; Taro Matsuo; Victoria Meadows; Gary F. Moore; Massimo Olivucci; Kevin E. Redding; Edward W. Schwieterman; Tejinder Singh; Kenji Takizawa; Anna Grace Ulses; Junko Yano; Felisa Wolfe-Simon; Michael L. Wong; Anastasia G. Yanchilina
Aaron McKinnon; Neveda Naz
Peter M. Higgins; Weibin Chen; Oliver Warr; Lucas M. Fifer; Wanying Kang; Charles S. Cockell; Barbara Sherwood Lollar
Caroline Haslebacher; Emeline Bolmont; Marco Cilibrasi; Jonathan Grone; Nico Haslebacher; Ravit Helled; Mathilde Kervazo; Niels F. W. Ligterink; Christophe Lovis; Lucio Mayer; Lorenzo Obersnel; Rafael Ottersberg; Apurva V. Oza; C. H. Lucas Patty; Antoine Pommerol; Ganna Portyankina; Alyssa R. Rhoden; Leander Schlarmann; Yuhito Shibaike; Vishaal Singh; Audrey H. Vorburger; Peter Wurz
Source record