Subglacial lakes on Mars

The square indicates color-coded results superimposed on the location of the reported subglacial lake at 193°E, 81°S.[1] Blue represents the area with the brightest radar reflection.

Salty subglacial lakes are controversially inferred from radar measurements to exist below the South Polar Layered Deposits (SPLD) in Ultimi Scopuli of Mars' southern ice cap.[1][2][3] The idea of subglacial lakes due to basal melting at the polar ice caps on Mars was first hypothesized in the 1980s.[4][5][6] For liquid water to persist below the SPLD, researchers propose that perchlorate is dissolved in the water, which lowers the freezing temperature,[1][2] but other explanations such as saline ice or hydrous minerals have been offered. Challenges for explaining sufficiently warm conditions for liquid water to exist below the southern ice cap include low amounts of geothermal heating from the subsurface and overlying pressure from the ice.[7] As a result, it is disputed whether radar detections of bright reflectors were instead caused by other materials such as saline ice[8] or deposits of minerals such as clays.[8][9] While lakes with salt concentrations 20 times that of the ocean pose challenges for life,[10] potential subglacial lakes on Mars are of high interest for astrobiology because microbial ecosystems have been found in deep subglacial lakes on Earth, such as in Lake Whillans in Antarctica below 800 m of ice.[11][12][13][14][15]

  1. ^ a b c Orosei, R.; Lauro, S. E.; Pettinelli, E.; Cicchetti, A.; Coradini, M.; Cosciotti, B.; Di Paolo, F.; Flamini, E.; Mattei, E.; Pajola, M.; Soldovieri, F. (2018-08-03). "Radar evidence of subglacial liquid water on Mars". Science. 361 (6401): 490–493. arXiv:2004.04587. Bibcode:2018Sci...361..490O. doi:10.1126/science.aar7268. ISSN 0036-8075. PMID 30045881. S2CID 206666385.
  2. ^ a b Lauro, Sebastian Emanuel; Pettinelli, Elena; Caprarelli, Graziella; Guallini, Luca; Rossi, Angelo Pio; Mattei, Elisabetta; Cosciotti, Barbara; Cicchetti, Andrea; Soldovieri, Francesco; Cartacci, Marco; Di Paolo, Federico (January 2021). "Multiple subglacial water bodies below the south pole of Mars unveiled by new MARSIS data". Nature Astronomy. 5 (1): 63–70. arXiv:2010.00870. Bibcode:2021NatAs...5...63L. doi:10.1038/s41550-020-1200-6. ISSN 2397-3366. S2CID 222125007.
  3. ^ "Liquid water spied deep below polar ice cap on Mars". www.science.org. Retrieved 2022-05-30.
  4. ^ fischer (2018-07-27). "Evidence of Subsurface Martian Liquid Water Bolstered". Planetary Science Institute. Retrieved 2022-06-03.
  5. ^ Witze, Alexandra (2018-07-25). "There's water on Mars! Signs of buried lake tantalize scientists". Nature. 560 (7716): 13–14. Bibcode:2018Natur.560...13W. doi:10.1038/d41586-018-05795-6. PMID 30065323. S2CID 51887407.
  6. ^ Clifford, Stephen M. (1987). "Polar basal melting on Mars". Journal of Geophysical Research. 92 (B9): 9135–9152. Bibcode:1987JGR....92.9135C. doi:10.1029/JB092iB09p09135. ISSN 0148-0227.
  7. ^ Sori, Michael M.; Bramson, Ali M. (2019-02-16). "Water on Mars, With a Grain of Salt: Local Heat Anomalies Are Required for Basal Melting of Ice at the South Pole Today". Geophysical Research Letters. 46 (3): 1222–1231. Bibcode:2019GeoRL..46.1222S. doi:10.1029/2018GL080985. hdl:10150/633584. ISSN 0094-8276. S2CID 134166238.
  8. ^ a b Bierson, C. J.; Tulaczyk, S.; Courville, S. W.; Putzig, N. E. (2021-07-16). "Strong MARSIS Radar Reflections From the Base of Martian South Polar Cap May Be Due to Conductive Ice or Minerals". Geophysical Research Letters. 48 (13). Bibcode:2021GeoRL..4893880B. doi:10.1029/2021GL093880. ISSN 0094-8276. S2CID 237755186.
  9. ^ Smith, I. B.; Lalich, D. E.; Rezza, C.; Horgan, B. H. N.; Whitten, J. L.; Nerozzi, S.; Holt, J. W. (August 2021). "A Solid Interpretation of Bright Radar Reflectors Under the Mars South Polar Ice". Geophysical Research Letters. 48 (15). Bibcode:2021GeoRL..4893618S. doi:10.1029/2021GL093618. ISSN 0094-8276. S2CID 237654444.
  10. ^ O'Callaghan, Jonathan (2020-09-28). "Water on Mars: discovery of three buried lakes intrigues scientists". Nature. doi:10.1038/d41586-020-02751-1. PMID 32989309. S2CID 222155190.
  11. ^ "Microbes Discovered in Subglacial Antarctic Lake May Hint at Life in Space". Animals. 2014-08-20. Archived from the original on August 2, 2021. Retrieved 2022-05-31.
  12. ^ Magazine, Smithsonian; Thompson, Helen. "Thousands of Microbe Species Live in This Buried Antarctic Lake". Smithsonian Magazine. Retrieved 2022-05-30.
  13. ^ Christner, Brent C.; Priscu, John C.; Achberger, Amanda M.; Barbante, Carlo; Carter, Sasha P.; Christianson, Knut; Michaud, Alexander B.; Mikucki, Jill A.; Mitchell, Andrew C.; Skidmore, Mark L.; Vick-Majors, Trista J. (August 2014). "A microbial ecosystem beneath the West Antarctic ice sheet". Nature. 512 (7514): 310–313. Bibcode:2014Natur.512..310.. doi:10.1038/nature13667. hdl:2160/30202. ISSN 1476-4687. PMID 25143114. S2CID 4470332.
  14. ^ Mikucki, J. A.; Lee, P. A.; Ghosh, D.; Purcell, A. M.; Mitchell, A. C.; Mankoff, K. D.; Fisher, A. T.; Tulaczyk, S.; Carter, S.; Siegfried, M. R.; Fricker, H. A. (2016-01-28). "Subglacial Lake Whillans microbial biogeochemistry: a synthesis of current knowledge". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. 374 (2059): 20140290. Bibcode:2016RSPTA.37440290M. doi:10.1098/rsta.2014.0290. hdl:2160/42715. PMID 26667908. S2CID 15307967.
  15. ^ Siegert, Martin J.; Priscu, John C.; Alekhina, Irina A.; Wadham, Jemma L.; Lyons, W. Berry (2016-01-28). "Antarctic subglacial lake exploration: first results and future plans". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. 374 (2059): 20140466. Bibcode:2016RSPTA.37440466S. doi:10.1098/rsta.2014.0466. PMC 4685969. PMID 26667917.