An extensive phase space for the potential martian biosphere.

We present a comprehensive model of martian pressure-temperature (P-T) phase space and compare it with that of Earth. Martian P-T conditions compatible with liquid water extend to a depth of ∼310 km. We use our phase space model of Mars and of terrestrial life to estimate the depths and extent of the water on Mars that is habitable for terrestrial life. We find an extensive overlap between inhabited terrestrial phase space and martian phase space. The lower martian surface temperatures and shallower martian geotherm suggest that, if there is a hot deep biosphere on Mars, it could extend 7 times deeper than the ∼5 km depth of the hot deep terrestrial biosphere in the crust inhabited by hyperthermophilic chemolithotrophs. This corresponds to ∼3.2% of the volume of present-day Mars being potentially habitable for terrestrial-like life.

[1]  C P McKay,et al.  On the possibility of chemosynthetic ecosystems in subsurface habitats on Mars. , 1992, Icarus.

[2]  V. Chevrier,et al.  Experimental investigation of the stability and evaporation of sulfate and chloride brines on Mars , 2009 .

[3]  L. Singh,et al.  Bacterial diversity of soil samples from the western Himalayas, India. , 2009, Canadian journal of microbiology.

[4]  J. Sleewaegen,et al.  Interior structure of terrestrial planets : Modeling Mars' mantle and its electromagnetic, geodetic, and seismic properties , 2005 .

[5]  O. Aharonson,et al.  Diffusion barriers at Mars surface conditions: Salt crusts, particle size mixtures, and dust , 2008 .

[6]  P. Christensen,et al.  Exposed Water Ice Discovered near the South Pole of Mars , 2002, Science.

[7]  Michael D. Smith,et al.  Comparison of atmospheric temperatures obtained through infrared sounding and radio occultation by Mars Global Surveyor , 2004 .

[8]  Farzam Javadpour,et al.  Relationship of permeability, porosity and depth using an artificial neural network , 2000 .

[9]  Michael H. Hecht,et al.  Metastability of liquid water on Mars , 2001 .

[10]  H. Jödicke.  Water and graphite in the Earth's crust —An approach to interpretation of conductivity models , 1992 .

[11]  T. Stenström,et al.  Thermophilic, anaerobic bacteria isolated from a deep borehole in granite in Sweden. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[12]  R. Mancinelli,et al.  Brines and evaporites: analogs for Martian life , 2004 .

[13]  A. Davila,et al.  Microbial colonization of Ca‐sulfate crusts in the hyperarid core of the Atacama Desert: implications for the search for life on Mars , 2011, Geobiology.

[14]  Nadine G. Barlow,et al.  An Introduction to its Interior, Surface and Atmosphere , 2008 .

[15]  Xu-sheng Wang,et al.  Evaluation of depth-dependent porosity and bulk modulus of a shear using permeability-depth trends , 2009 .

[16]  K. Stetter.  History of discovery of the first hyperthermophiles , 2006, Extremophiles.

[17]  D. Turcotte,et al.  Is the Martian crust also the Martian elastic lithosphere , 2002 .

[18]  J W Head,et al.  Internal structure and early thermal evolution of Mars from Mars Global Surveyor topography and gravity. , 2000, Science.

[19]  Dirk Schulze-Makuch,et al.  A possible biogenic origin for hydrogen peroxide on Mars: the Viking results reinterpreted , 2006, International Journal of Astrobiology.

[20]  Cheng-Haw Lee,et al.  A simple method of estimating rock mass porosity and permeability , 1990 .

[21]  P. Price.  A habitat for psychrophiles in deep Antarctic ice. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[22]  N. Cabrol,et al.  On the possibility of liquid water on present‐day Mars , 2001 .

[23]  Roger N. Anderson,et al.  Permeability Versus Depth in the Upper Oceanic Crust' In Situ Measurements in DSDP Hole 504B, Eastern Equatorial Pacific , 1985 .

[24]  P. Mazur.  Limits to life at low temperatures and at reduced water contents and water activities , 1980, Origins of life.

[25]  M. Mellon,et al.  Subfreezing activity of microorganisms and the potential habitability of Mars' polar regions. , 2003, Astrobiology.

[26]  Jody W. Deming,et al.  Bacterial Activity at −2 to −20°C in Arctic Wintertime Sea Ice , 2004, Applied and Environmental Microbiology.

[27]  Amitabha Ghosh,et al.  An integrated view of the chemistry and mineralogy of martian soils , 2005, Nature.

[28]  Donald L. Turcotte,et al.  Geodynamics : applications of continuum physics to geological problems , 1982 .

[29]  D. Möhlmann.  The influence of van der Waals forces on the state of water in the shallow subsurface of Mars , 2008 .

[30]  Jean-Pierre Bibring,et al.  Hydration state of the Martian surface as seen by Mars Express OMEGA: 2. H2O content of the surface , 2007 .

[31]  Bruce Fegley,et al.  The Planetary Scientist's Companion , 1998 .

[32]  J. Heldmann,et al.  Cold springs in permafrost on Earth and Mars , 2002 .

[33]  C. Clauser,et al.  Thermal Conductivity of Rocks and Minerals , 2013 .

[34]  R..  Water in the lower continental crust : modelling magnetotelluric and seismic reflection results * , 2006 .

[35]  C. McKay,et al.  Facilitation of endolithic microbial survival in the hyperarid core of the Atacama Desert by mineral deliquescence , 2008 .

[36]  Maria T. Zuber,et al.  The crust and mantle of Mars , 2001, Nature.

[37]  Daniel T. Britt,et al.  Stony meteorite porosities and densities: A review of the data through 2001 , 2003 .

[38]  Carol R. Stoker,et al.  Possible physical and thermodynamical evidence for liquid water at the Phoenix landing site , 2009 .

[39]  D. Schulze-Makuch,et al.  Assessing the plausibility of life on other worlds. , 2001, Astrobiology.

[40]  K. Ingvorsen,et al.  Temperature characteristics of bacterial iron solubilisation and 14C assimilation in naturally exposed sulfide ore material at Citronen Fjord, North Greenland (83°N) , 1997 .

[41]  Derek W. G. Sears,et al.  On laboratory simulation and the evaporation rate of water on Mars , 2005 .

[42]  Maria T. Zuber,et al.  Thickness of the Martian crust: Improved constraints from geoid-to-topography ratios , 2004 .

[43]  Terry Z. Martin,et al.  Thermal and albedo mapping of Mars during the Viking primary mission , 1977 .

[44]  David L. Bish,et al.  Magnesium sulphate salts and the history of water on Mars , 2004, Nature.

[45]  D. Möhlmann,et al.  Water in the upper martian surface at mid- and low-latitudes: presence, state, and consequences , 2004 .

[46]  K. Pedersen.  Exploration of deep intraterrestrial microbial life: current perspectives. , 2000, FEMS microbiology letters.

[47]  M. Mellon,et al.  Mars low-latitude neutron distribution: Possible remnant near-surface water ice and a mechanism for its recent emplacement , 2005 .

[48]  G. Horneck.  The microbial world and the case for Mars , 2000 .

[49]  Andreas Lorek,et al.  Survival potential and photosynthetic activity of lichens under Mars-like conditions: a laboratory study. , 2010, Astrobiology.

[50]  L. F. Athy.  Density, Porosity, and Compaction of Sedimentary Rocks , 1930 .

[51]  H. Chafetz,et al.  Anatomy of siliceous hot springs: examples from Yellowstone National Park, Wyoming, USA , 2003 .

[52]  J. Frisvad,et al.  Extremophilic fungi in arctic ice: a relationship between adaptation to low temperature and water activity , 2003 .

[53]  G. Marion,et al.  Br/Cl partitioning in chloride minerals in the Burns formation on Mars , 2009 .

[54]  E. Jagoutz.  Salt-induced rock fragmentation on Mars: The role of salt in the weathering of Martian rocks , 2006 .

[55]  C. Lineweaver,et al.  To what extent does terrestrial life "follow the water"? , 2010, Astrobiology.

[56]  M. Toksöz,et al.  Thermal history and evolution of Mars , 1978 .

[57]  A. Gooday,et al.  Simple Foraminifera Flourish at the Ocean's Deepest Point , 2005, Science.

[58]  Mary A. Voytek,et al.  Findings of the Mars special regions science analysis group. , 2006, Astrobiology.

[59]  G. Marion,et al.  Modeling aqueous perchlorate chemistries with applications to Mars , 2009 .

[60]  Thomas Koop,et al.  Homogeneous Ice Nucleation in Water and Aqueous Solutions , 2004 .

[61]  Jacques Jose,et al.  Water vapour pressure above saturated salt solutions at low temperatures , 1999 .

[62]  D. Lovley,et al.  Extending the Upper Temperature Limit for Life , 2003, Science.

[63]  N. Hoffman.  White Mars: A New Model for Mars' Surface and Atmosphere Based on CO2 , 2000 .

[64]  H. Waenke,et al.  The bulk composition, mineralogy and internal structure of Mars , 1992 .

[65]  Imshenetsky Aa,et al.  Upper boundary of the biosphere , 1978, Applied and environmental microbiology.

[66]  Jean-Pierre Bibring,et al.  Sulfates in Martian Layered Terrains: The OMEGA/Mars Express View , 2005, Science.

[67]  Romică Creţu,et al.  Food Chemistry , 2021 .

[68]  David E. Smith,et al.  Correction to “Localized gravity/topography admittance and correlation spectra on Mars: Implications for regional and global evolution” , 2004 .

[69]  D. Schulze-Makuch,et al.  The prospect of alien life in exotic forms on other worlds , 2006, Naturwissenschaften.

[70]  N. Christensen.  Compressional and Shear Wave Velocities in Basaltic Rocks, Deep Sea Drilling Project, Leg 16 , 1973 .

[71]  T. Davis.  Permafrost: A guide to Frozen Ground in Transition , 2001 .

[72]  Irina N Mitskevich,et al.  Microflora of the deep glacier horizons of Central Antarctica , 1998 .

[73]  M. Mellon,et al.  Effects of soil heterogeneity on martian ground-ice stability and orbital estimates of ice table depth , 2005 .

[74]  S. Clifford.  Mars: Crustal pore volume, cryospheric depth, and the global occurrence of groundwater , 1986 .

[75]  P. Price,et al.  Temperature dependence of metabolic rates for microbial growth, maintenance, and survival. , 2004, Proceedings of the National Academy of Sciences of the United States of America.

[76]  T. Gudkova,et al.  Mars: interior structure and excitation of free oscillations , 2004 .

[77]  S. I. Bragin,et al.  The Dynamic Albedo of Neutrons (DAN) experiment for NASA's 2009 Mars Science Laboratory. , 2008, Astrobiology.

[78]  M. Mellon.  Limits on the CO2Content of the Martian Polar Deposits , 1996 .

[79]  R. M. Prol-Ledesma.  Similarities in the chemistry of shallow submarine hydrothermal vents , 2003 .

[80]  Dirk Schulze-Makuch,et al.  Microbial life in a liquid asphalt desert. , 2010, Astrobiology.

[81]  Y. Fei,et al.  Mineralogy of the Martian interior up to core‐mantle boundary pressures , 1997 .

[82]  D. Yuan,et al.  The relationship between Martian gravity and topography , 2002 .

[83]  Tilman Spohn,et al.  The interior structure of Mars: Implications from SNC meteorites , 1997 .

[84]  K. Horikoshi,et al.  Microbial flora in the deepest sea mud of the Mariana Trench. , 1997, FEMS microbiology letters.

[85]  P. McClintock.  Mars: an introduction to its interior, surface and atmosphere. , 2008 .

[86]  C. McKay,et al.  Metabolic Activity of Permafrost Bacteria below the Freezing Point , 2000, Applied and Environmental Microbiology.

[87]  A. Márquez,et al.  Evidence of gully formation by regional groundwater flow in the Gorgonum Newton region (Mars) , 2005 .

[88]  Duwayne M. Anderson,et al.  PREDICTING UNFROZEN WATER CONTENTS IN FROZEN SOILS FROM SURFACE AREA MEASUREMENTS , 1972 .

[89]  Dirk Schulze-Makuch,et al.  Life in the Universe , 2008 .

[90]  A. Jafari,et al.  Relationships between permeability, porosity and pore throat size in carbonate rocks using regression analysis and neural networks , 2006 .

[91]  Thomas H. Prettyman,et al.  The presence and stability of ground ice in the southern hemisphere of Mars , 2004 .

[92]  D. Möhlmann.  Temporary liquid water in upper snow/ice sub-surfaces on Mars? , 2010 .

[93]  Christopher P. McKay,et al.  Formation of Martian Gullies by the Action of Liquid Water Flowing Under Current Martian Environmental Conditions , 2005 .

[94]  Final Four Landing Sites for the Mars Science Laboratory , 2011 .

[95]  Dylan Chivian,et al.  Environmental Genomics Reveals a Single-Species Ecosystem Deep Within Earth , 2008, Science.

[96]  Viscosity of liquid ferric sulfate solutions and application to the formation of gullies on Mars , 2009 .

[97]  M. Mellon,et al.  Recent gullies on Mars and the source of liquid water , 2001 .

[98]  D. Möhlmann.  The three types of liquid water in the surface of present Mars , 2009, International Journal of Astrobiology.

[99]  Michael D. Smith,et al.  Mars Global Surveyor Thermal Emission Spectrometer (Tes) Observations: Atmospheric Temperatures During Aerobraking and Science Phasing , 2013 .

[100]  W. Grant.  Life at low water activity. , 2004, Philosophical transactions of the Royal Society of London. Series B, Biological sciences.

[101]  T. Wong,et al.  Laboratory measurement of compaction-induced permeability change in porous rocks: Implications for the generation and maintenance of pore pressure excess in the crust , 1994 .

[102]  C. N. Hewitt,et al.  Handbook of atmospheric science: principles and applications. , 2003 .

[103]  W. Derbyshire,et al.  NMR studies of water adsorbed on a number of silica surfaces , 1974 .

[104]  Tilman Spohn,et al.  Geophysical constraints on the composition and structure of the Martian interior , 2005 .

[105]  M. Saar,et al.  Depth dependence of permeability in the Oregon cascades inferred from hydrogeologic, thermal, seismic, and magmatic modeling constraints , 2004 .

[106]  M. Ovenden.  Life in the Universe: Expectations and Constraints , 1963 .

[107]  L. Irwin,et al.  Life in the Universe: Expectations and Constraints , 2004 .

[108]  Shaopeng Huang,et al.  CLIMATE RECONSTRUCTION FROM SUBSURFACE TEMPERATURES , 2000 .

[109]  Karsten Pedersen,et al.  The deep subterranean biosphere , 1993 .

[110]  Manasi Karkare,et al.  Nontechnical Guide To Petroleum Geology, Exploration, Drilling And Production , 2013 .

[111]  Ross A. Beyer,et al.  A comparison of methods used to estimate the height of sand dunes on Mars , 2006 .

[112]  T. Gold,et al.  The deep, hot biosphere. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[113]  M. Mellon,et al.  High-Resolution Thermal Inertia Mapping from the Mars Global Surveyor Thermal Emission Spectrometer , 2000 .

[114]  S. Benner,et al.  Is there a common chemical model for life in the universe? , 2004, Current opinion in chemical biology.

[115]  T. Encrenaz,et al.  Mars Surface Diversity as Revealed by the OMEGA/Mars Express Observations , 2005, Science.

[116]  W. Martin,et al.  Hydrothermal vents and the origin of life , 2008, Nature Reviews Microbiology.

[117]  A. Pavlov,et al.  Growth of microorganisms in Martian-like shallow subsurface conditions: laboratory modelling , 2009, International Journal of Astrobiology.

[118]  G. Horneck.  The microbial case for Mars and its implication for human expeditions to Mars , 2008 .

[119]  R. Tye,et al.  thermal conductivity , 2019 .

[120]  G. Davies,et al.  The internal activity and thermal evolution of Earth-like planets , 2008 .

[121]  Robert B. Leighton,et al.  The Surface of Mars , 2007 .

[122]  D. James.  The thermal diffusivity of ice and water between −40 and + 60° C , 1968 .

[123]  Daria Morozova,et al.  Survival of Methanogenic Archaea from Siberian Permafrost under Simulated Martian Thermal Conditions , 2007, Origins of Life and Evolution of Biospheres.

[124]  W. Folkner,et al.  Interior structure and seasonal mass redistribution of Mars from radio tracking of Mars Pathfinder. , 1997, Science.

[125]  K. Stuwe,et al.  Geodynamics of the Lithosphere: An Introduction , 2003 .

[126]  B. Luo,et al.  Water activity as the determinant for homogeneous ice nucleation in aqueous solutions , 2000, Nature.

[127]  J. Amend,et al.  Palaeococcus helgesonii sp. nov., a facultatively anaerobic, hyperthermophilic archaeon from a geothermal well on Vulcano Island, Italy , 2003, Archives of Microbiology.

[128]  C. Lineweaver,et al.  Using the phase diagram of liquid water to search for life , 2012 .

[129]  J. Houtkooper,et al.  A Perchlorate Strategy for Extreme Xerophilic Life on Mars , 2010 .

[130]  J. Rummel,et al.  Preventing the forward contamination of Mars: concerns, questions, and required actions , 2006, 2006 IEEE Aerospace Conference.

[131]  C. N. Hewitt,et al.  Handbook of Atmospheric Science , 2003 .

[132]  V. Chevrier,et al.  Low temperature aqueous ferric sulfate solutions on the surface of Mars , 2008 .

[133]  P. Christensen.  Regional dust deposits on Mars - Physical properties, age, and history , 1986 .

[134]  S. McLennan,et al.  Martian surface heat production and crustal heat flow from Mars Odyssey Gamma‐Ray spectrometry , 2011 .

[135]  D. Griffin.  Non-spore forming eubacteria isolated at an altitude of 20,000 m in Earth’s atmosphere: extended incubation periods needed for culture-based assays , 2008 .

[136]  David E. Smith,et al.  Crustal structure of Mars from gravity and topography , 2004 .

[137]  D. Möhlmann.  Adsorption water-related potential chemical and biological processes in the upper martian surface. , 2005, Astrobiology.

[138]  M. Wainwright,et al.  Microorganisms cultured from stratospheric air samples obtained at 41 km. , 2003, FEMS microbiology letters.

[139]  E. Kladivko,et al.  Soil macroporosity, hydraulic conductivity and air permeability of silty soils under long-term conservation tillage in Indiana , 1988 .

[140]  A. Knoll,et al.  Water Activity and the Challenge for Life on Early Mars , 2008, Science.

[141]  Sean C. Solomon,et al.  Localized gravity/topography admittance and correlation spectra on Mars: Implications for regional and global evolution , 2002 .

[142]  G. Landis.  Martian water: are there extant halobacteria on Mars? , 2001, Astrobiology.

[143]  Ernst Huenges,et al.  The permeable crust: Geohydraulic properties down to 9101 m depth , 1997 .

[144]  S. Ingebritsen,et al.  Geological implications of a permeability-depth curve for the continental crust , 1999 .

[145]  Deborah S. Kelley,et al.  Incidence and Diversity of Microorganisms within the Walls of an Active Deep-Sea Sulfide Chimney , 2003, Applied and Environmental Microbiology.

[146]  I. Abdulagatov,et al.  Effect of pressure and temperature on the thermal conductivity of rocks , 2006 .

[147]  Sean C. Solomon,et al.  Heterogeneities in the thickness of the elastic lithosphere of Mars - Constraints on heat flow and internal dynamics , 1990 .

[148]  P. Christensen.  Formation of recent martian gullies through melting of extensive water-rich snow deposits , 2003, Nature.

[149]  M. Muskat,et al.  The Measurement of the Permeability of Porous Media for Homogeneous Fluids , 1933 .

[150]  P. Christensen,et al.  A model of thermal conductivity for planetary soils: 2. Theory for cemented soils , 2009 .

[151]  James B Garvin,et al.  Following the water, the new program for Mars exploration. , 2002, Acta astronautica.

[152]  T. Esman.  Atmosphere of Mars , 1948, Nature.

[153]  S. Ingebritsen,et al.  Permeability of the continental crust: Implications of geothermal data and metamorphic systems , 1999 .

[154]  Jennifer Lynne Heldmann,et al.  Observations of martian gullies and constraints on potential formation mechanisms , 2004 .

[155]  M. Mellon,et al.  Observations of martian gullies and constraints on potential formation mechanisms. II. The northern hemisphere , 2007 .

[156]  J. Priscu,et al.  The potential for lithoautotrophic life on Mars: application to shallow interfacial water environments. , 2007, Astrobiology.

[157]  W. Bains.  Many chemistries could be used to build living systems. , 2004, Astrobiology.

[158]  Satoshi Nakagawa,et al.  Cell proliferation at 122°C and isotopically heavy CH4 production by a hyperthermophilic methanogen under high-pressure cultivation , 2008, Proceedings of the National Academy of Sciences.

[159]  Amitabha Ghosh,et al.  One Martian year of atmospheric observations using MER Mini‐TES , 2006 .