Mars methane detection and variability at Gale crater
Of water and methane on Mars
The Curiosity rover has been collecting data for the past 2 years, since its delivery to Mars (see the Perspective by Zahnle). Many studies now suggest that many millions of years ago, Mars was warmer and wetter than it is today. But those conditions required an atmosphere that seems to have vanished. Using the Curiosity rover, Mahaffy et al. measured the ratio of deuterium to hydrogen in clays that were formed 3.0 to 3.7 billion years ago. Hydrogen escapes more readily than deuterium, so this ratio offers a snapshot measure of the ancient atmosphere that can help constrain when and how it disappeared. Most methane on Earth has a biological origin, so planetary scientists have keenly pursued its detection in the martian atmosphere as well. Now, Webster et al. have precisely confirmed the presence of methane in the martian atmosphere with the instruments aboard the Curiosity rover at Gale crater.
Abstract
Reports of plumes or patches of methane in the martian atmosphere that vary over monthly time scales have defied explanation to date. From in situ measurements made over a 20-month period by the tunable laser spectrometer of the Sample Analysis at Mars instrument suite on Curiosity at Gale crater, we report detection of background levels of atmospheric methane of mean value 0.69 ± 0.25 parts per billion by volume (ppbv) at the 95% confidence interval (CI). This abundance is lower than model estimates of ultraviolet degradation of accreted interplanetary dust particles or carbonaceous chondrite material. Additionally, in four sequential measurements spanning a 60-sol period (where 1 sol is a martian day), we observed elevated levels of methane of 7.2 ± 2.1 ppbv (95% CI), implying that Mars is episodically producing methane from an additional unknown source.
Supplementary Material
Summary
Materials and Methods
Supplementary Text
Figs. S1 to S13
Tables S1 and S2
The MSL Science Team Author List
Resources
File (webster.sm.pdf)
References and Notes
1
Atreya S. K., Mahaffy P. R., Wong A. S., Methane and related trace species on Mars: Origin, loss, implications for life, and habitability. Planet. Space Sci. 55, 358–369 (2007).
2
Krasnopolsky V. A., Maillard J. P., Owen T. C., Detection of methane in the martian atmosphere: Evidence for life? Icarus 172, 537–547 (2004).
3
Oze C., Sharma M., Have olivine, will gas: Serpentinization and the abiogenetic production of methane on Mars. Geophys. Res. Lett. 32, L10203 (2005).
4
Keppler F., Vigano I., McLeod A., Ott U., Früchtl M., Röckmann T., Ultraviolet-radiation-induced methane emissions from meteorites and the martian atmosphere. Nature 486, 93–96 (2012).
5
Schuerger A., Moores J. E., Clausen C. A., Barlow N. G., Britt D. T., Methane from UV-irradiated carbonaceous chondrites under simulated martian conditions. J. Geophys. Res. 117, E08007 (2012).
6
Poch O., Kaci S., Stalport F., Szopa C., Coll P., Laboratory insights into the chemical and kinetic evolution of several organic molecules under simulated Mars surface UV radiation conditions. Icarus 242, 50–63 (2014).
7
Krasnopolsky V. A., Some problems related to the origin of methane on Mars. Icarus 180, 359–367 (2006).
8
Chassefière E., Metastable methane clathrate particles as a source of methane to the martian atmosphere. Icarus 204, 137–144 (2009).
9
Meslin P.-Y., Gough R., Lefevre L., Forget F., Little variability of methane on Mars induced by adsorption in the regolith. Planet. Space Sci. 59, 247–258 (2011).
10
Gough R. V., Tolbert M. A., McKay C. P., Toon O. B., Methane adsorption on a martian soil analog: An abiogenic explanation for methane variability in the martian atmosphere. Icarus 207, 165–174 (2010).
11
McMahon S., Parnell J., Blamey N. J. F., Sampling methane in basalt on Earth and Mars. Int. J. Astrobiol. 12, 113–122 (2013).
12
Etiope G., Oehler D. Z., Allen C. C., Methane emissions from Earth’s degassing: Implications for Mars. Planet. Space Sci. 59, 182–195 (2011).
13
Mumma M. J., Villanueva G. L., Novak R. E., Hewagama T., Bonev B. P., Disanti M. A., Mandell A. M., Smith M. D., Strong release of methane on Mars in northern summer 2003. Science 323, 1041–1045 (2009).
14
Formisano V., Atreya S., Encrenaz T., Ignatiev N., Giuranna M., Detection of methane in the atmosphere of Mars. Science 306, 1758–1761 (2004).
15
Geminale A., Formisano V., Sindoni G., Mapping methane in martian atmosphere with PFS-MEX data. Planet. Space Sci. 59, 137–148 (2011).
16
Fonti S., Marzo G. A., Mapping the methane on Mars. Astron. Astrophys. 512, A51 (2010).
17
V. A. Krasnopolsky, A sensitive search for methane and ethane on Mars, EPSC Abstracts 6, 49 (2011).
18
Krasnopolsky V. A., Search for methane and upper limits to ethane and SO2 on Mars. Icarus 217, 144–152 (2012).
19
Villanueva G. L., Mumma M. J., Novak R. E., Radeva Y. L., Käufl H. U., Smette A., Tokunaga A., Khayat A., Encrenaz T., Hartogh P., A sensitive search for organics (CH4, CH3OH, H2CO, C2H6, C2H2, C2H4), hydroperoxyl (HO2), nitrogen compounds (N2O, NH3, HCN) and chlorine species (HCl, CH3Cl) on Mars using ground-based high-resolution infrared spectroscopy. Icarus 223, 11–27 (2013).
20
Lefèvre F., Forget F., Observed variations of methane on Mars unexplained by known atmospheric chemistry and physics. Nature 460, 720–723 (2009).
21
Atreya S. K., Witasse O., Chevrier V. F., Forget F., Mahaffy P. R., Buford Price P., Webster C. R., Zurek R. W., Methane on Mars: Current observations, interpretations, and future plans. Planet. Space Sci. 59, 133–136 (2011).
22
Zahnle K. J., Freedman R. S., Catling D. C., Is there methane on Mars? Icarus 212, 493–503 (2011).
23
P. R. Christensen, Mars as seen from the 2001 Mars Odyssey Thermal Emission Imaging System experiment. Eos Trans. AGU Fall Meet. Suppl. 84 (46), Abstract P21A-02 (2003).
24
Gaillard F., Michalski J., Berger G., McLennan S. M., Scaillet B., Geochemical reservoirs and timing of sulfur cycling on Mars. Space Sci. Rev. 174, 251–300 (2013).
25
Mischna M. A., Allen M., Richardson M. I., Newman C. E., Toigo A. D., Atmospheric modeling of Mars methane surface releases. Planet. Space Sci. 59, 227–237 (2011).
26
Atreya S. K., Wong A. S., Renno N. O., Farrell W. M., Delory G. T., Sentman D. D., Cummer S. A., Marshall J. R., Rafkin S. C., Catling D. C., Oxidant enhancement in martian dust devils and storms: Implications for life and habitability. Astrobiology 6, 439–450 (2006).
27
Delory G. T., Farrell W. M., Atreya S. K., Renno N. O., Wong A. S., Cummer S. A., Sentman D. D., Marshall J. R., Rafkin S. C., Catling D. C., Oxidant enhancement in martian dust devils and storms: Storm electric fields and electron dissociative attachment. Astrobiology 6, 451–462 (2006).
28
Farrell W. M., Delory G. T., Atreya S. K., Martian dust storms as a possible sink of atmospheric methane. J. Geophys. Res. 33, L21203 (2006).
29
Mahaffy P. R., Webster C. R., Cabane M., Conrad P. G., Coll P., Atreya S. K., Arvey R., Barciniak M., Benna M., Bleacher L., Brinckerhoff W. B., Eigenbrode J. L., Carignan D., Cascia M., Chalmers R. A., Dworkin J. P., Errigo T., Everson P., Franz H., Farley R., Feng S., Frazier G., Freissinet C., Glavin D. P., Harpold D. N., Hawk D., Holmes V., Johnson C. S., Jones A., Jordan P., Kellogg J., Lewis J., Lyness E., Malespin C. A., Martin D. K., Maurer J., McAdam A. C., McLennan D., Nolan T. J., Noriega M., Pavlov A. A., Prats B., Raaen E., Sheinman O., Sheppard D., Smith J., Stern J. C., Tan F., Trainer M., Ming D. W., Morris R. V., Jones J., Gundersen C., Steele A., Wray J., Botta O., Leshin L. A., Owen T., Battel S., Jakosky B. M., Manning H., Squyres S., Navarro-González R., McKay C. P., Raulin F., Sternberg R., Buch A., Sorensen P., Kline-Schoder R., Coscia D., Szopa C., Teinturier S., Baffes C., Feldman J., Flesch G., Forouhar S., Garcia R., Keymeulen D., Woodward S., Block B. P., Arnett K., Miller R., Edmonson C., Gorevan S., Mumm E., The Sample Analysis at Mars investigation and instrument suite. Space Sci. Rev. 170, 401–478 (2012).
30
Webster C. R., Mahaffy P. R., Determining the local abundance of martian methane and its’ 13C/12C and D/H isotopic ratios for comparison with related gas and soil analysis on the 2011 Mars Science Laboratory (MSL) mission. Planet. Space Sci. 59, 271–283 (2011).
31
Webster C. R., Mahaffy P. R., Flesch G. J., Niles P. B., Jones J. H., Leshin L. A., Atreya S. K., Stern J. C., Christensen L. E., Owen T., Franz H., Pepin R. O., Steele A.the MSL Science Team, Isotope ratios of H, C, and O in CO2 and H2O of the martian atmosphere. Science 341, 260–263 (2013).
32
See supplementary materials on Science Online.
33
Webster C. R., Mahaffy P. R., Atreya S. K., Flesch G. J., Farley K. A.MSL Science Team, Low upper limit to methane abundance on Mars. Science 342, 355–357 (2013).
34
C. Freissinet et al., “Organic molecules in the Sheepbed mudstone of Gale crater, Mars,” 8th International Conference on Mars, Abstract 1349, Pasadena, CA, 14 to 18 July 2014; www.hou.usra.edu/meetings/8thmars2014/pdf/1349.pdf.
35
Garry J. R. C., ten Kate I. L., Martins Z., Nørnberg P., Ehrenfreund P., Analysis and survival of amino acids in martian regolith analogs. Meteorit. Planet. Sci. 41, 391–405 (2006).
36
Gómez-Elvira J., Armiens C., Carrasco I., Genzer M., Gómez F., Haberle R., Hamilton V. E., Harri A.-M., Kahanpää H., Kemppinen O., Lepinette A., Martín Soler J., Martín-Torres J., Martínez-Frías J., Mischna M., Mora L., Navarro S., Newman C., de Pablo M. A., Peinado V., Polkko J., Rafkin S. C. R., Ramos M., Rennó N. O., Richardson M., Rodríguez-Manfredi J. A., Romeral Planelló J. J., Sebastián E., de la Torre Juárez M., Torres J., Urquí R., Vasavada A. R., Verdasca J., Zorzano M.-P., Curiosity’s rover environmental monitoring station: Overview of the first 100 sols. J. Geophys. Res. 119, 1680–1688 (2014).
37
T. H. McConnochie et al., “ChemCam passive spectroscopy of atmospheric O2 and H2O,” 8th International Conference on Mars, Abstract 1328, Pasadena, CA, 14 to 18 July 2014; www.hou.usra.edu/meetings/8thmars2014/pdf/1328.pdf.
38
Hassler D. M., Zeitlin C., Wimmer-Schweingruber R. F., Böttcher S., Martin C., Andrews J., Böhm E., Brinza D. E., Bullock M. A., Burmeister S., Ehresmann B., Epperly M., Grinspoon D., Köhler J., Kortmann O., Neal K., Peterson J., Posner A., Rafkin S., Seimetz L., Smith K. D., Tyler Y., Weigle G., Reitz G., Cucinotta F. A., The Radiation Assessment Detector (RAD) investigation. Space Sci. Rev. 170, 503–558 (2012).
39
M. T. Lemmon, “The Mars Science Laboratory optical depth record,” 8th International Conference on Mars, Abstract 1338, Pasadena, CA, 14 to 18 July 2014; www.hou.usra.edu/meetings/8thmars2014/pdf/1338.pdf.
40
Geminal A., et al., Methane in martian atmosphere: Average spatial, diurnal and seasonal behavior. Planet. Space Sci. 56, 1194–1203 (2008).
41
M. E. Schmidt et al., “Geochemical classification of rocks in Gale crater with APXS to sol 360: Sediment provenance, mixing, and diagenetic processes,” 45th Lunar and Planetary Science Conference, Abstract 1504, The Woodlands, TX, 17 to 21 March 2014; www.hou.usra.edu/meetings/lpsc2014/pdf/1504.pdf.
42
H. K. Newsom et al., “Gale crater and impact processes from Curiosity,” 45th Lunar and Planetary Science Conference, Abstract 2103, The Woodlands, TX, 17 to 21 March 2014; www.hou.usra.edu/meetings/lpsc2014/pdf/2103.pdf.
43
Rothman L. S., Gordon I. E., Barbe A., Benner D. C., Bernath P. F., Birk M., Boudon V., Brown L. R., Campargue A., Champion J.-P., Chance K., Coudert L. H., Dana V., Devi V. M., Fally S., Flaud J.-M., Gamache R. R., Goldman A., Jacquemart D., Kleiner I., Lacome N., Lafferty W. J., Mandin J.-Y., Massie S. T., Mikhailenko S. N., Miller C. E., Moazzen-Ahmadi N., Naumenko O. V., Nikitin A. V., Orphal J., Perevalov V. I., Perrin A., Predoi-Cross A., Rinsland C. P., Rotger M., Šimečková M., Smith M. A. H., Sung K., Tashkun S. A., Tennyson J., Toth R. A., Vandaele A. C., Vander Auwera J., The HITRAN 2008 molecular spectroscopic database. J. Quant. Spectrosc. Radiat. Transfer 110, 533–572 (2009).
44
C. R. Webster, R. T. Menzies, E. D. Hinkley, “Infrared laser absorption: theory and applications,” in Laser Remote Chemical Analysis, R. M. Measures, Ed. (Wiley, New York, 1988), chap. 3.
45
A. Buch et al., “Detection of organics at Mars: How wet chemistry onboard SAM helps,” 44th Lunar and Planetary Science Conference, abstract 1512, The Woodlands, TX, 18 to 22 March 2013; www.lpi.usra.edu/meetings/lpsc2013/pdf/1512.pdf.
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Science
Volume 347 | Issue 6220
23 January 2015
23 January 2015
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Copyright © 2015, American Association for the Advancement of Science.
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Received: 24 September 2014
Accepted: 5 December 2014
Published in print: 23 January 2015
Acknowledgments
The research described here was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. Data described in the paper are further described in the supplementary materials and have been submitted to NASA’s Planetary Data System (PDS) under an arrangement with the Mars Science Laboratory (MSL) project. Funding is acknowledged for J.M.-T. and M.-P.Z. from the Spanish Ministry of Economy and Competiveness, J.C.B. from the UK Space Agency, and R.G. from the Canadian Space Agency.