Can salt move through ice on exoplanets to give life a chance?

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Image by Christian Bodhi from Pixabay
Image by Christian Bodhi from Pixabay

Oceans on water-rich exoplanets may be enriched with electrolytes, including salts such as sodium chloride, according to international researchers, which is an important factor in the search for life. The team wanted to know if minerals could make it to the liquid water surface of planets where the high pressures create an ice sheet between the mineral-rich rocky core and the watery surface. They used computer modelling simulations and found that salts like sodium chloride could be transported through the ice sheet into the water ocean above. An accompanying comment suggests that this study “offers the most convincing argument yet in resolving the dilemma of large planetary hydrosphere habitability.”

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From: Springer Nature

Planetary science: Modelling electrolyte transport in water-rich exoplanets

Oceans on water-rich exoplanets may be enriched with electrolytes, including salts such as sodium chloride, suggests a modelling study published in Nature Communications. The research proposes electrolytes can be transported from the rocky core of these planets and may have implications for the potential habitability of these ocean worlds. 

Water-rich exoplanets and icy moons are promising environments for biological processes to take place. The planets are formed of a rocky core separated from the liquid water by a high-pressure ice shell. It has been debated whether the transport of electrolytes from the rocky core into the liquid ocean is hindered by the ice shell.

Jean-Alexis Hernandez and colleagues used molecular dynamics simulations and thermodynamic modelling to explore how electrolytes could be transported between the ice layer and the ocean on these planets. The authors found that salts, such as sodium chloride, could be incorporated in the high pressure ice shells and transported through the ice into the ocean. They argue this demonstrates that high-pressure ice mantles may not act as chemical barriers between rocky cores and liquid water oceans.

Writing in an accompanying Comment Baptiste Journaux suggests the study, “offers the most convincing argument yet in resolving the dilemma of large planetary hydrosphere habitability.”

Journal/
conference:
Nature Communications
Research:Paper
Organisation/s: European Synchrotron Radiation Facility, France
Funder: Additional computational resources were provided by the Norwegian infrastructure for highperformance computing (NOTUR grants NN9329K, NN2916K, and NN9697K). R.C. was funded by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement n°681818 – IMPACT) and by the Deep Carbon Observatory under a grant from the Extreme Physics and Chemistry Directorate. J.A.H. and R.C. were funded by the Research Council of Norway through its Centres of Excellence funding scheme, project number 223272. SL was funded by a grant from the Agence Nationale de la Recherche (ANR) under project number ANR-15-CE31-0018-01.
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