Solar UV Irradiation Conditions on the Surface of Mars ¶

The UV radiation environment on planetary surfaces and within atmospheres is of importance in a wide range of scientific disciplines. Solar UV radiation is a driving force of chemical and organic evolution and serves also as a constraint in biological evolution. In this work we modeled the transmission of present and early solar UV radiation from 200 to 400 nm through the present‐day and early (3.5 Gyr ago) Martian atmosphere for a variety of possible cases, including dust loading, observed and modeled O3 concentrations. The UV stress on microorganisms and/or molecules essential for life was estimated by using DNA damaging effects (specifically bacteriophage T7 killing and uracil dimerization) for various irradiation conditions on the present and ancient Martian surface. Our study suggests that the UV irradiance on the early Martian surface 3.5 Gyr ago may have been comparable with that of present‐day Earth, and though the current Martian UV environment is still quite severe from a biological viewpoint, we show that substantial protection can still be afforded under dust and ice.

[1]  K. Módos,et al.  Construction of spectral sensitivity function using polychromatic UV sources. , 1999, Journal of photochemistry and photobiology. B, Biology.

[2]  G. Rontó,et al.  Use of Uracil Thin Layer for Measuring Biologically Effective UV Dose , 1996, Photochemistry and photobiology.

[3]  Y L Yung,et al.  Loss of atmosphere from Mars due to solar wind-induced sputtering , 1995, Science.

[4]  Yuk L. Yung,et al.  The loss of atmosphere from Mars - Response , 1996 .

[5]  G. Horneck,et al.  The History of the UV Radiation Climate of the Earth—Theoretical and Space‐based Observations ¶ , 2001, Photochemistry and photobiology.

[6]  S. Atreya,et al.  Solar radiation incident on the Martian surface , 1979, Journal of Molecular Evolution.

[7]  Y. Lvov,et al.  Structure of bacteriophage T7. Small-angle X-ray and neutron scattering study. , 1983, Biophysical journal.

[8]  Helmut Lammer,et al.  Loss of H and O from Mars : Implications for the planetary water inventory , 1996 .

[9]  Franck Selsis,et al.  Signature of life on exoplanets: Can Darwin produce false positive detections? , 2002 .

[10]  E. Friedmann,et al.  The cryptoendolithic microbial environment in the Ross Desert of Antarctica: Light in the photosynthetically active region , 2005, Microbial Ecology.

[11]  Jimmy D Bell,et al.  Absorption and scattering properties of the Martian dust in the solar wavelengths. , 1997, Journal of geophysical research.

[12]  H. Lammer,et al.  Nonthermal atmospheric escape from Mars and Titan , 1991 .

[13]  G. Anderson,et al.  Mariner 9 Ultraviolet Spectrometer Experiment: Seasonal Variation of Ozone on Mars , 1973, Science.

[14]  Gerda Horneck,et al.  Quantification of the biological effectiveness of environmental UV radiation , 1995 .

[15]  A. Bérces,et al.  Monitoring of environmental UV radiation by biological dosimeters. , 2000, Advances in space research : the official journal of the Committee on Space Research.

[16]  M. Carr Retention of an atmosphere on early Mars , 1999 .

[17]  T. Coohill ACTION SPECTRA AGAIN? * , 1991, Photochemistry and photobiology.

[18]  C. Cockell,et al.  The ultraviolet environment of Mars: biological implications past, present, and future. , 2000, Icarus.

[19]  Y. Furusawa,et al.  Biological and physical dosimeters for monitoring solar UV-B light. , 1990, Journal of radiation research.

[20]  D. Shemansky,et al.  CO2 Extinction Coefficient 1700–3000 Å , 1972 .

[21]  K. Zahnle,et al.  The evolution of solar ultraviolet luminosity , 1982 .

[22]  R. Prinn,et al.  Mars: Photodesorption from mineral surfaces and its effects on atmospheric stability , 1977 .

[23]  Rocco L. Mancinelli,et al.  Martian soil and UV radiation: microbial viability assessment on spacecraft surfaces , 2000 .

[24]  H. D. Holland When did the Earth's atmosphere become oxic? A Reply , 1999 .

[25]  G. Rontó,et al.  Influence of spectral and angular sensitivity on the readout of biological dosimeters. , 1999, Journal of photochemistry and photobiology. B, Biology.

[26]  L. Roza,et al.  Assessment of the Effects of Various UV Sources on Inactivation and Photoproduct Induction in Phage T7 Dosimeter , 1998, Photochemistry and photobiology.

[27]  F. Leblanc,et al.  Sputtering of the Martian atmosphere by solar wind pick-up ions , 2001 .

[28]  J. Kasting,et al.  Sulfur, ultraviolet radiation, and the early evolution of life , 2005, Origins of life and evolution of the biosphere.

[29]  Manish R. Patel,et al.  Ultraviolet radiation on the surface of Mars and the Beagle 2 UV sensor , 2002 .

[30]  A. Anbar,et al.  A photochemical model of the martian atmosphere. , 1994, Icarus.

[31]  G. Rontó,et al.  Biological UV dosimetry-a comprehensive problem , 1995 .

[32]  B. Lewis,et al.  Temperature dependence of the carbon dioxide photoabsorption cross section between 1200 and 1970 Å , 1983 .

[33]  G. Rontó,et al.  ULTRAVIOLET DOSIMETRY IN OUTDOOR MEASUREMENTS BASED ON BACTERIOPHAGE T7 AS A BIOSENSOR , 1994 .

[34]  Genotoxic action of sunlight upon Bacillus subtilis spores: monitoring studies at Tokyo, Japan. , 1989, Journal of radiation research.

[35]  R. Huguenin Mars - Chemical weathering as a massive volatile sink , 1976 .

[36]  R. Tyrrell SOLAR DOSIMETRY WITH REPAIR DEFICIENT BACTERIAL SPORES: ACTION SPECTRA, PHOTOPRODUCT MEASUREMENTS AND A COMPARISON WITH OTHER BIOLOGICAL SYSTEMS , 1978, Photochemistry and photobiology.

[37]  B. L. Olla,et al.  DNA AS A SOLAR DOSIMETER IN THE OCEAN * , 1990, Photochemistry and photobiology.

[38]  Michael H. Carr,et al.  Water on Mars , 1987, Nature.

[39]  G. Horneck,et al.  A BIOFILM USED AS ULTRAVIOLET‐DOSIMETER , 1992 .

[40]  J. Pollack,et al.  Properties and effects of dust particles suspended in the Martian atmosphere , 1979 .

[41]  R. Huguenin Chemical weathering and the Viking biology experiments on Mars. , 1982 .