Skip to main content Accessibility help

An active nitrogen cycle on Mars sufficient to support a subsurface biosphere

  • C.S. Boxe (a1), K.P. Hand (a1), K.H. Nealson (a2), Y.L. Yung (a3) and A. Saiz-Lopez (a1) (a4)...

Mars' total atmospheric nitrogen content is 0.2 mbar. One-dimensional (1D) photochemical simulations of Mars' atmosphere show that nitric acid (HNO3(g)), the most soluble nitrogen oxide, is the principal reservoir species for nitrogen in its lower atmosphere, which amounts to a steady-state value of 6×10−2 kg or 4 moles, conditions of severe nitrogen deficiency. Mars could, however, support ∼1015 kg of biomass (∼1 kg N m−2) from its current atmospheric nitrogen inventory. The terrestrial mass ratio of nitrogen in biomass to that in the atmosphere is ∼10−5; applying this ratio to Mars yields ∼1010 kg of total biomass – also, conditions of severe nitrogen deficiency. These amounts, however, are lower limits as the maximum surface-sink of atmospheric nitrogen is 2.8 mbar (9×1015 kg of N), which indicates, in contradistinction to the Klingler et al. (1989), that biological metabolism would not be inhibited in the subsurface of Mars. Within this context, we explore HNO3 deposition on Mars' surface (i.e. soil and ice-covered regions) on pure water metastable thin liquid films. We show for the first time that the negative change in Gibbs free energy increases with decreasing HNO3(g) (NO3(aq)) in metastable thin liquid films that may exist on Mars' surface. We also show that additional reaction pathways are exergonic and may proceed spontaneously, thus providing an ample source of energy for nitrogen fixation on Mars. Lastly, we explore the dissociation of HNO3(g) to form NO3(aq) in metastable thin liquid films on the Martian surface via condensed phase simulations. These simulations show that photochemically produced fixed nitrogen species are not only released from the Martian surface to the gas-phase, but more importantly, transported to lower depths from the Martian surface in transient thin liquid films. A putative biotic layer at 10 m depth would produce HNO3 and N2 sinks of −54 and −5×1012 molecules cm−2 s−1, respectively, which is an ample supply of available nitrogen that can be efficiently transported to the subsurface. The downward transport as well as the release to the atmosphere of photochemically produced fixed nitrogen species (e.g. NO2, NO and NO2) suggests the existence of a transient but active nitrogen cycle on Mars.

Corresponding author
Hide All
Bogard, D.D., Clayton, R.N., Marti, K., Owen, T. & Turner, G. (2001). Space. Sci. Rev. 96, 425458.
Boxe, C.S. & Saiz-Lopez, A. (2008). Atmos. Chem. Phys. 8, 48554864.
Boxe, C.S. et al. (2003). J. Phys. Chem. A 107, 1140911413.
Boxe, C.S. et al. (2005). J. Phys. Chem. A 109, 85208525.
Boxe, C.S. et al. (2006). J. Phys. Chem. A 110, 76137616.
Boxe, C.S. et al. (2011). Int. J. Astrobiol. submitted.
Bullock, M., Stoker, C., McKay, C. & Zent, A. (1994). Icarus 107, 142154.
Capone, D.G., Popa, R., Flood, B. & Nealson, K. (2006). Science 312, 708709.
Dubowski, Y., Colussi, A.J., Boxe, C.S. & Hoffmann, M.R. (2002). J. Phys. Chem. A 106, 69676971.
Ducluzeau, A.-L., Lis, R.V., Duval, S., Schoepp-Cothenet, B., Russell, M. & Nitschke, W. (2009). Trends Biochem. Sci. 34, 915.
Field, C.B., Behrenfeld, M.J., Randerson, J.T. & Falkowski, P. (1998). Science 281, 237240.
Fox, J.L. & Delgarno, A. (1983). J. Geophys. Res. 88(A11), 90279032.
Graham, R.C., Hirmas, D.R., Wood, Y.A. & Amrhein, C. (2008). Geology 36, 259262.
Grannas, A.M., Bausch, A.R. & Mahanna, K.M. (2007). J. Phys. Chem. A 111, 1104311049.
Grannas, A.M., Shepson, P.B. & Filley, T.R. (2004). Global Biogeochem. Cycles 18, doi: 10.1029/2003GB002133, GB1006(1-10).
Harman, H. & McKay, C. (1995). Planet. Space Sci. 43, 123128.
Huber, H. et al. (2002). Nature 417, 6367.
Jakosky, B.M. & Phillips, R.L. (2001). Nature 412, 237244.
King, M.D., France, J.L., Fisher, F.N. & Beine, H.J. (2005). J. Photochem. Photobiol. A 176, 3949.
Klingler, J.M., Mancinelli, R.L. & White, M.R. (1989). Adv. Space Res. 9, 173176.
Lide, David R. (eds) (2006). CRC Handbook of Chemistry and Physics, 89th edn (Internet Version 2009). CRC Press/Taylor and Francis, Boca Raton, FL.
Mack, J. & Bolton, J.R. (1999). J. Photochem. and Photobiol. A 128, 113.
Mancinelli, R.L. & Banin, A. (2003). Int. J. Astrobiol. 2, 217225.
McElroy, M.B., Kong, T.Y. & Yung, Y.L. (1977). J. Geophys. Res. 82, 43794388.
McKay, C.P. & Stoker, C.R. (1989). Rev. Geophys. 27, 189214.
Mellon, M. & Jakosky, B. (1993). J. Geophys. Res. 98, 33433364.
Price, P.B. (2007). Microbiol. Ecol. 59, 217231.
Qiu, R., Green, S.A., Honrath, R.E., Peterson, M.C., Lu, Y. & Dziobak, M. (2002). Atmos. Environ. 36, 25632571.
Rubio, L.M. & Ludden, P.W. (2005). J. Bacteriol. 187, 405414.
Squyres, S.W., Clifford, S.M., Kuzmin, R.O., Zimbelman, J.R. & Costard, F.M. (1992). In Mars, ed. Kieffer, H., Jakosky, B., Snyder, C. & Matthews, M., pp. 523554. University of Arizona Press, Tuscon, AZ.
Summers, D.P. & Khare, B. (2007). Astrobiology 7, 333, doi: 10.1089/ast.2006.0032.
Takenaka, N. et al. (1996). J. Phys. Chem. 100, 1387413884.
Walvoord, M.A. et al. (2003). Science 302, 10211024.
Weiss, B.P., Yung, Y.L. & Nealson, K.H. (2000). Proc. Natl Acad. Sci. USA 97, 13951399.
Yung, Y.L. & Demore, W.B. (1999). Photochemistry of Planetary Atmospheres, Oxford University Press, Oxford.
Zehr, J.P., Jenkins, B.D., Short, M.D. & Steward, G.F. (2005). Environ. Microb. 5, 539554.
Zuo, Y. & Deng, Y. (1998). Chemosphere 36, 181188.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

International Journal of Astrobiology
  • ISSN: 1473-5504
  • EISSN: 1475-3006
  • URL: /core/journals/international-journal-of-astrobiology
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed