Despite the faint young Sun, early Earth might have been kept warm by an atmosphere containing the greenhouse gases CH4 and CO2 in mixing ratios higher than those found on Earth today. Laboratory and modeling studies suggest that an atmosphere containing these trace gases could lead to the formation of organic aerosol haze due to UV photochemistry. Chemical mechanisms proposed to explain haze formation rely on CH4 as the source of carbon and treat CO2 as a source of oxygen only, but this has not previously been verified experimentally. In the present work, we use isotopically labeled precursor gases and unit-mass resolution (UMR) and high-resolution (HR) aerosol mass spectrometry to examine the sources of carbon and oxygen to photochemical aerosol formed in a CH4/CO2/N2 atmosphere. UMR results suggest that CH4 contributes 70–100% of carbon in the aerosol, while HR results constrain the value from 94% to 100%. We also confirm that CO2 contributes approximately 10% of the total mass to the aerosol as oxygen. These results have implications for the geochemical interpretations of inclusions found in Archean rocks on Earth and for the astrobiological potential of other planetary atmospheres. Key Words: Atmosphere—Early Earth—Planetary atmospheres—Carbon dioxide—Methane. Astrobiology 16, 822–830.
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References
1.
AikenA.C., DeCarloP.F., and JimenezJ.L. (2007) Elemental analysis of organic species with electron ionization high-resolution mass spectrometry. Anal Chem, 79:8350–8358.
2.
AikenA.C., DeCarloP.F., KrollJ.H., WorsnopD.R., HuffmanJ.A., DochertyK.S., UlbrichI.M., MohrC., KimmelJ.R., SueperD., SunY., ZhangQ., TrimbornA., NorthwayM., ZiemannP.J., CanagaratnaM.R., OnaschT.B., AlfarraM.R., PrevotA.S.H., DommenJ., DuplissyJ., MetzgerA., BaltenspergerU., and JimenezJ.L. (2008) O/C and OM/OC ratios of primary, secondary, and ambient organic aerosols with high-resolution time-of-flight aerosol mass spectrometry. Environ Sci Technol, 42:4478–4485.
3.
AllanJ.D., JimenezJ.L., WilliamsP.I., AlfarraM.R., BowerK.N., JayneJ.T., CoeH., and WorsnopD.R. (2003) Quantitative sampling using an Aerodyne aerosol mass spectrometer 1. Techniques of data interpretation and error analysis. J Geophys Res, 108, doi:10.1029/2002JD002358.
4.
AllanJ.D., DeliaA.E., CoeH., BowerK.N., AlfarraM., JimenezJ.L., MiddlebrookA.M., DrewnickF., OnaschT.B., CanagaratnaM.R., JayneJ.T., and WorsnopD.R. (2004) A generalised method for the extraction of chemically resolved mass spectra from Aerodyne aerosol mass spectrometer data. J Aerosol Sci, 35:909–922.
5.
BellE.A., BoehnkeP., HarrisonT.M., and MaoW.L. (2015) Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon. Proc Natl Acad Sci USA, 112, doi:10.1073/pnas.1517557112.
6.
BlakeR.E., ChangS.J., and LeplandA. (2010) Phosphate oxygen isotopic evidence for a temperate and biologically active Archaean ocean. Nature, 464:1029–1033.
7.
CableM.L., HörstS.M., HodyssR., BeauchampP.M., SmithM.A., and WillisP.A. (2012) Titan tholins: simulating Titan organic chemistry in the Cassini-Huygens era. Chem Rev, 112:1882–1909.
8.
CanagaratnaM.R., JayneJ.T., JimenezJ.L., AllanJ.D., AlfarraM.R., ZhangQ., OnaschT.B., DrewnickF., CoeH., MiddlebrookA., DeliaA., WilliamsL.R., TrimbornA.M., NorthwayM.J., DeCarloP.F., KolbC.E., DavidovitsP., and WorsnopD.R. (2007) Chemical and microphysical characterization of ambient aerosols with the Aerodyne aerosol mass spectrometer. Mass Spectrom Rev, 26:185–222.
9.
CanagaratnaM.R., JimenezJ.L., KrollJ.H., ChenQ., KesslerS.H., MassoliP., Hildebrandt RuizL., FortnerE., WilliamsL.R., WilsonK.R., SurrattJ.D., DonahueN.M., JayneJ.T., and WorsnopD.R. (2015) Elemental ratio measurements of organic compounds using aerosol mass spectrometry: characterization, improved calibration, and implications. Atmos Chem Phys, 15:253–272.
10.
ClaireM.W., SheetsJ., CohenM., RibasI., MeadowsV., and CatlingD.C. (2012) The evolution of solar flux from 0.1 nm to 160 μm: quantitative estimates for planetary studies. Astrophys J, 757:1–11.
DetwilerC.R., GarrettD.L., PurcellJ.D., and TouseyR. (1961) Tome 17-Fascicule 3 Juillet-Septembre t961. In Annales de Géophysique, Centre National de la Recherche Scientifique, p. 263.
13.
DeWittH.L., HasenkopfC.A., TrainerM.G., FarmerD.K., JimenezJ.L., McKayC.P., ToonO.B., and TolbertM.A. (2010) The formation of sulfate and elemental sulfur aerosols under varying laboratory conditions: implications for early Earth. Astrobiology, 10:773–781.
14.
DorrenJ.D. and GuinanE.F. (1994) HD 129333: the Sun in its infancy. Astrophys J, 428:805–818.
15.
GansB., PengZ., CarrascoN., GauvacqD., LebonnoisS., and PernotP. (2013) Impact of a new wavelength-dependent representation of methane photolysis branching ratios on the modeling of Titan's atmospheric photochemistry. Icarus, 223:330–343.
16.
GoughD. (1981) Solar interior structure and luminosity variations. Sol Phys, 74:21–34.
17.
Haqq-MisraJ., KastingJ.F., and LeeS. (2011) Availability of O2 and H2O2 on pre- photosynthetic Earth. Astrobiology, 11:293–302.
18.
HasenkopfC.A., BeaverM.R., TrainerM.G., DewittH.L., FreedmanM.A., ToonO.B., McKayC.P., and TolbertM.A. (2010) Optical properties of Titan and early Earth haze laboratory analogs in the mid-visible. Icarus, 207:903–913.
19.
HicksR.K., DayD.A., JimenezJ.L, and TolbertM.A. (2015) Elemental analysis of complex organic aerosol using isotopic labeling and unit-resolution mass spectrometry. Anal Chem, 87:2741–2747.
20.
HrenM.T., TiceM.M., and ChamberlainC.P. (2009) Oxygen and hydrogen isotope evidence for a temperate climate 3.42 billion years ago. Nature, 462:205–208.
21.
JayneJ.T., LeardD.C., ZhangX., DavidovitsP., SmithK.A., KolbC.E., and WorsnopD.R. (2000) Development of an aerosol mass spectrometer for size and composition analysis of submicron particles. Aerosol Sci Technol, 33:49–70.
22.
KastingJ., ZahnleK., and WalkerJ. (1983) Photochemistry of methane in the Earth's early atmosphere. Precambrian Res, 20:121–148.
23.
Keller-RudekH., MoortgatG.K., SanderR., and SörensenR. (2013) The MPI-Mainz UV/VIS spectral atlas of gaseous molecules of atmospheric interest. Earth Syst Sci Data, 5:365–373.
24.
LuZ., ChangY.C., YinQ.-Z., NgC.Y., and JacksonW.M. (2014) Evidence for direct molecular oxygen production in CO2 photodissociation. Science, 346:61–64.
25.
MarleyM.S., AckermanA.S., CuzziJ.N., and KitzmannD. (2013) Clouds and hazes in exoplanet atmospheres. Comparative Climatology of Terrestrial Planets, 1:367–391.
26.
MojzsisS.J., ArrheniusG., McKeeganK.D., HarrisonT.M., NutmanA.P., and FriendC.R.L. (1996) Evidence for life on Earth before 3,800 million years ago. Nature, 384:55–59.
27.
MoldoveanuS. (2009) Pyrolysis of Organic Molecules: Applications to Health and Environmental Issues, Elsevier Science, Amsterdam, pp 7–19.
28.
MordauntD.H., LambertI.R., MorleyG.P., AshfoldM.N.R., DixonR.N., WesternC.M., SchniederL., and WelgeK.H. (1993) Primary product channels in the photodissociation of methane at 121.6 nm. J Chem Phys, 98:2054–2065.
29.
PavlovA.A., KastingJ.F., BrownL.L, RagesK.A., and FreedmanR. (2000) Greenhouse warming by CH4 in the atmosphere of early Earth. J Geophys Res, 105:11981–11990.
30.
PavlovA.A., KastingJ.F., EigenbrodeJ.L., and FreemanK.H. (2001a) Organic haze in Earth's early atmosphere: source of low-13C Late Archean kerogens?. Geology, 29:1003–1006.
31.
PavlovA.A., BrownL.L., and KastingJ.F. (2001b) UV shielding of NH3 and O2 by organic hazes in the Archean atmosphere. J Geophys Res, 106:23267–23287.
32.
SaganC. and KhareB.N. (1979) Tholins: organic chemistry of interstellar grains and gas. Nature, 277:102–107.
33.
SaganC. and MullenG. (1972) Earth and Mars: evolution of atmospheres and surface temperatures. Science, 177:52–56.
34.
SchmidtJ.A., JohnsonM.S., and SchinkeR. (2013) Carbon dioxide photolysis from 150 to 210 nm: singlet and triplet channel dynamics, UV-spectrum, and isotope effects. Proc Natl Acad Sci USA, 110:17691–17696.
35.
SeguraA., MeadowsV., KastingJ.F., CrispD., and CohenM. (2007) Abiotic formation of O2 and O3 in high-CO2 terrestrial atmospheres. Astron Astrophys, 472:665–680.
36.
SueperD.T., DunleaE., CrosierJ., KimmelJ., DeCarloP., AikenA.C., and JimenezJ.L. (2007) A community software for quality control and analysis of data from the Aerodyne time-of-flight aerosol mass spectrometers (ToF-AMS). In Annual Conference of the American Association for Aerosol Research, Reno, NV.
TrainerM.G., PavlovA.A., DeWittH.L., JimenezJ.L., McKayC.P., ToonO.B., and TolbertM.A. (2006) Organic haze on Titan and the early Earth. Proc Natl Acad Sci USA, 103:18035–18042.
39.
TrainerM.G., JimenezJ.L., YungY.L., ToonO.B., and TolbertM.A. (2012) Nitrogen incorporation in CH4-N2 photochemical aerosol produced by far ultraviolet irradiation. Astrobiology, 4:315–326.
40.
WolfE. and ToonO. (2010) Fractal organic hazes provided an ultraviolet shield for early Earth. Science, 328:1266–1268.
41.
YoonY.H., HorstS.M., HicksR.K., LiR., de GouwJ.A., and TolbertM.A. (2014) The role of benzene photolysis in Titan haze formation. Icarus, 233:233–241.
42.
YoshinoK., EsmondJ., SunY., ParkinsonW., ItoK., and MatsuiT. (1996) Absorption cross section measurements of carbon dioxide in the wavelength region 118.7–175.5 nm and the temperature dependence. J Quant Spectrosc Radiat Transfer, 55:53–60.
43.
YungY.L., AllenM., and PintoJ.P. (1984) Photochemistry of the atmosphere of Titan: comparison between model and observations. Astrophys J Suppl Ser, 55:465–506.
44.
ZahnleK.J. (1986) Photochemistry of methane and the formation of hydrocyanic acid (HCN) in the Earth's early atmosphere. J Geophys Res, 91:2819–2834.
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