Skip to main content

Could photosynthesis function on Proxima Centauri b?

  • Raymond J. Ritchie (a1), Anthony W.D. Larkum (a2) and Ignasi Ribas (a3)

Could oxygenic and/or anoxygenic photosynthesis exist on planet Proxima Centauri b? Proxima Centauri (spectral type – M5.5 V, 3050 K) is a red dwarf, whereas the Sun is type G2 V (5780 K). The light regimes on Earth and Proxima Centauri b are compared with estimates of the planet's suitability for Chlorophyll a (Chl a) and Chl d-based oxygenic photosynthesis and for bacteriochlorophyll (BChl)-based anoxygenic photosynthesis. Proxima Centauri b has low irradiance in the oxygenic photosynthesis range (400–749 nm: 64–132 µmol quanta m−2 s−1). Much larger amounts of light would be available for BChl-based anoxygenic photosynthesis (350–1100 nm: 724–1538 µmol quanta m−2 s−1). We estimated primary production under these light regimes. We used the oxygenic algae Synechocystis PCC6803, Prochlorothrix hollandica, Acaryochloris marina, Chlorella vulgaris, Rhodomonas sp. and Phaeodactylum tricornutum and the anoxygenic photosynthetic bacteria Rhodopseudomonas palustris (BChl a), Afifella marina (BChl a), Thermochromatium tepidum (BChl a), Chlorobaculum tepidum (BChl a + c) and Blastochloris viridis (BChl b) as representative photosynthetic organisms. Proxima Centauri b has only ≈3% of the PAR (400–700 nm) of Earth irradiance, but we found that potential gross photosynthesis (P g) on Proxima Centauri b could be surprisingly high (oxygenic photosynthesis: earth ≈0.8 gC m−2 h−1; Proxima Centauri b ≈0.14 gC m−2 h−1). The proportion of PAR irradiance useable by oxygenic photosynthetic organisms (the sum of Blue + Red irradiance) is similar for the Earth and Proxima Centauri b. The oxygenic photic zone would be only ≈10 m deep in water compared with ≈200 m on Earth. The P g of an anoxic Earth (gC m−2 h−1) is ≈0.34–0.59 (land) and could be as high as ≈0.29–0.44 on Proxima Centauri b. 1 m of water does not affect oxygenic or anoxygenic photosynthesis on Earth, but on Proxima Centauri b oxygenic P g is reduced by ≈50%. Effective elimination of near IR limits P g by photosynthetic bacteria (<10% of the surface value). The spectrum of Proxima Centauri b is unfavourable for anoxygenic aquatic photosynthesis. Nevertheless, a substantial aerobic or anaerobic ecology is possible on Proxima Centauri b. Protocols to recognize the biogenic signature of anoxygenic photosynthesis are needed.

Corresponding author
e-mail: and
Hide All
Allen M.M. (1973). Methods for cyanophyceae. In Handbook of Phycological Methods: Culture Methods and Growth Measurements, ed. Stein J.R. pp. 127138. Cambridge University Press, Cambridge, UK.
Anbar A.D. et al. (2007). A whiff of oxygen before the great oxidation event? Science 317, 19031906. doi: 10.1126/science.1140325.
Anderson D.T., Sumner D.Y., Hawes I., Webster-Brown J. & McKay C.P. (2011). Discovery of large conical stromatolites in Lake Untersee, Antarctica. Geobiology 9, 280293.
Anglada-Escudé G., Tuomi M., Gerlach E., Barnes R., Heller R. & Jenkins J.S. (2013). A dynamically-packed planetary system around GJ 667C with three super-Earths in its habitable zone. Astron. Astrophys. 553, A126, doi: 10.1051/0004-6361/201321331
Anglada-Escudé G. et al. (2016). A terrestrial planet candidate in a temperate orbit around Proxima Centauri b. Nature 536, 437440, doi: 10.1038/nature19106
Audard M., Güdel M., Drake J.J. & Kashyap V.L. (2000). Extreme-ultraviolet flare activity in late-type stars. Astrophys. J. 541, 396409.
Bailey J. (2014). The dawes review 3: the atmospheres of extrasolar planets and brown dwarfs. Publ. Astron. Soc. Aust. 31, e043, 36 pp, doi: 10.1017/pasa.2014.38
Baraffe I., Homeier D., Allard F. & Chabrier G. (2015). New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit. Astron. Astrophys. 577, A42.
Blank C.E. & Sanchez-Baracaldo P. (2010). Timing of morphological and ecological innovations in the cyanobacteria – a key to understanding the rise in atmospheric oxygen. Geobiology 8, 123. doi: 10.1111/j.1472-4669.2009.00220.x
Blankenship R.E., Madigan M.T. & Bauer C.E. (1995). Anoxygenic Photosynthetic Bacteria. Kluwer Academic Publishers, Dordrecht, The Netherlands.
Bolmont E., Raymond S.N., Leconte J., Correia A. & Quintana E. (2014a). Tidal evolution in multiple planet systems: application to Kepler-62 and Kepler-186. In Complex Planetary Systems, ed. Knezevic Z. & Lemaître A. Proceedings IAU Symposium No. 310, 2014, p. 5861. arXiv:1410.7428v1 [astro-ph.EP], Namur, Belgium 7–11 July 2014, Cambridge University Press, Cambridge, U.K.
Bolmont E., Raymond S.N., von Paris P., Selsis F., Hersant F., Quintana E.V. & Barclay T. (2014b). Formation, Tidal Evolution, and Habitability of the Kepler-186 System. Astrophys. J. 793, 3, 16pp, doi: 10.1088/0004-636X/793/1/3
Bryant D.B. & Frigaard N-U. (2006). Prokaryotic photosynthesis and phototrophy illuminated. Trends Microbiol. 14, 488496.
Buccino A.P., Mauas P.J.D. & Lemarchand G.A. (2002). UV radiation in different stellar systems. Bioastronomy 2002: Life Among the Stars IAU Symposium, vol. 213, ed. Norris R.P. & Stootman F.H., pp. 97100.
Buccino A.P., Lemarchand G.A. & Mauas P.J.D. (2007). UV habitable zones around M stars. Icarus 192, 582587.
Burke C.M. & Burton H.R. (1988). Photosynthetic bacteria in meromictic lakes and stratified fjords of the Vestfold Hills, Antarctica. Hydrobiologia 165, 1323.
Cardona T. (2015). A fresh look at the evolution and diversification of photochemical reaction centers. Photosynth. Res. 126, 111–34.
Cardona T. (2016). Reconstructing the origin of oxygenic photosynthesis: do assembly and photoactivation recapitulate evolution? Front. Plant Sci. 7, 257, doi: 10.3389/fpls.2016.00257
Catling D.C., Glein C.R., Zahnle K.J. & McKay C.P. (2005). Why O2 is required by complex life on habitable planets and the concept of planetary ‘oxygenation time’. Astrobiology 5(3), 416438.
Chen M. & Scheer H. (2013). Extending the limits of natural photosynthesis and implications for technical light harvesting. J. Porphyr. Phthalocya. 17, 115, doi: 10.1142/S1088424612300108
Chopra A. & Lineweaver C.H. (2016). The case for a gaian bottleneck: the biology of habitability. Astrobiology 16, 722.
Cockell C.S., Kaltenegger L. & Raven J.A. (2009a). Cryptic photosynthesis–extrasolar planetary oxygen without a surface biological signature. Astrobiology 9, 623636.
Cockell C.S., Raven J.A., Kaltenegger L. & Logan R.C. (2009b). Planetary targets in the search for extrasolar oxygenic photosynthesis. Plant Ecol. Divers. 2, 207219.
Cohen Y., Krumbein W.E. & Shilo M. (1977). Solar Lake (Sinai). 2. Distribution of photosynthetic microorganisms and primary production. Limnol. Oceanogr. 22, 609620.
Cole G.H.A. & Woolfson M.M. (2002). Planetary Science: The Science of Planets Around Stars. Institute of Physics Publ., Bristol and Philadelphia. pp. 381382 and appendix pp. 442450.
Crowe S.A., Døssing L.N., Beukes N.J., Bau M., Kruger S.J., Frei R. & Canfield D.E. (2013). Atmospheric oxygenation three billion years ago. Nature 501, 535539. doi: 10.1038/nature12426
Cummings M.E. & Zimmerman R.C. (2003). Light harvesting and the package effect in the seagrasses Thalassia testudinum Banks ex Königand Zostera marina L.: optical constraints on photoacclimation. Aquat. Bot. 75, 261274.
Davenport J.R.A., Kipping D.M., Sasselov D., Matthews J.M. & Cameron C. (2016). MOST observations of our nearest neighbour: flares on Proxima Centauri. Astrophys. J. 829, L31.
Djokic T.D., Van Kranendonk M.J., Campbell K.A., Walter M.R. & Ward C.R. (2017). Earliest signs of life on land preserved in ca 3.5 Ga hot spring deposits. Nat. Commun. 8, 15263, doi: 10.138/ncomms15263
Domagal-Goldman S.D., Kasting J.F., Johnston D.T. & Farquhar J. (2008). Organic haze, glaciations and multiple sulphur isotopes in the Mid-Archean Era Earth Planet. Sci. Lett. 269, 2940.
Duxbury Z., Schliep M., Ritchie R.J., Larkum A.W.D. & Min Chen M. (2009). Chromatic photoacclimation extends utilisable photosynthetically active radiation in the chlorophyll d-containing cyanobacterium, Acaryochloris marina . Photosynth. Res. 101, 6975.
Edson E., Lee S-Y., Bannon P., Kasting J.F. & Pollard D. (2011). Atmospheric circulations of terrestrial planets orbiting low-mass stars. Icarus 212, 113, doi: 10.1016/j.icarus.2010.11.023 (2017) (accessed 9 January 2017).
Falkowski P.G. & Raven J.A. (2007). Aquatic Photosynthesis, 2nd edn. Princeton University Press, Princeton.
Falkowski P.G., Greene R. & Kolber Z. (1994). Light utilization and photoinhibition of photosynthesis in marine phytoplankton. In Photoinhibition of Photosynthesis from Molecular Mechanisms to the Field, ed. Baker N.R. & Bowyer J.R., pp. 407432. BIOS Scientific Publ., Oxford.
Fischer W.W., Hemp J. & Johnson J.E. (2016). Evolution of oxygenic photosynthesis. Ann. Rev. Earth Planet. Sci. 44, 647683.
French C.S. (1937a). The quantum yield of hydrogen and carbon dioxide assimilation in purple bacteria. J. Gen. Physiol. 20, 711735.
French C.S. (1937b). The rate of CO2 assimilation by purple bacteria at various wavelengths of light. J. Gen. Physiol. 21, 7187.
Gale J. & Wandel A. (2016). The potential of planets orbiting red dwarf stars to support oxygenic photosynthesis and complex life. Int. J. Astrobiol., Published online: 03 June 2016, DOI:
Gan F., Zhang S.Y., Rockwell N.C., Martin S.S., Lagarias J.C. & Bryant D.A. (2014). Extensive remodelling of a cyanobacterial photosynthetic apparatus in far-red light. Science 345, 13121317.
Gitelson A., Stark R., Oron G. & Dor I. (1997). Monitoring of polluted water bodies by remote sensing. In Remote Sensing and Geographic Information Systems for Design and Operation of Water Resources Systems (Proc. of Rabat Symp. S3, April 1997). IAHS Publ. No 242, 1997, pp. 181188.
Gitelson A., Stark R., Dor I., Michielson O. & Yacobi Y.Z. (1999). Optical characteristics of the phototroph Thiocapsa roseopersicina and implication for real time monitoring of the bacteriochlorophyll concentration. Appl. Environ. Microbiol. 65, 33923397.
Gloag R.S., Ritchie R.J., Chen M., Larkum A.W.D. & Quinnell R.G. (2007). Chromatic photoacclimation, photosynthetic electron transport and oxygen evolution in the chlorophyll d-containing oxyphotobacterium Acaryochloris marina . Biochim. Biophys. Acta – Bioenerg. 1767(2), 127135.
Gobel F. (1978). Quantum efficiencies of growth. In The Photosynthetic Bacteria, Chapter 50, ed. Feher G., Okamura M.Y., Clayton R.K. & Sistrom W.R., pp. 907925. Plenum Press, New York.
Haqq-Misra J., Kasting J.F. & Lee S-Y. (2010). Availability of O2 and H2O2 on Pre-Photosynthetic Earth. Astrobiology 11, 293302.
Heller R. & Barnes R. (2013). Exomoon habitability constrained by illumination and tidal heating. Astrobiology 13, 1846, doi: 10.1089/ast.2012.0859
Hellingwerf K.J., de Vrij W. & Konings W.N. (1982). Wavelength dependence of energy transduction in Rhodopseudomonas sphaeroides: action spectrum of growth. J. Bacteriol. 151, 534541.
Herbert R.A. (1985). Development of mass blooms of photosynthetic bacteria on sheltered beaches in Scapa Flow, Orkney Islands. P. R. Soc. Edinb. B 87, 1525, doi: 10.1017/S0269727000004139
Hohmann-Marriott M.F. & Blankenship R.E. (2011). Evolution of photosynthesis. Annu. Rev. Plant Biol. 62, 515548.
Howard A.W. (2013). Observed properties of extrasolar planets. Science 340, 572576, doi: 10.1126/science.1233545
Hubas C., Jesus B., Passarelli C. & Jeanthon C. (2011). Tools providing new insight into coastal anoxygenic purple bacterial mats. Res. Microbiol. 162, 858868.
Johnston D.T., Wolfe-Simon F., Pearson A. & Knoll A.H. (2009). Anoxygenic photosynthesis modulated proterozoic oxygen and sustained Earth's middle age. P. Nat. Acad. Sci. USA 106, 1692516929.
Jones B.W. & Sleep P.N. (2010). Habitability of exoplanetary systems with planets observed in transit. Mon. Not. R. Astron. Soc. 407, 12591267, doi: 10.1111/j.1365-2966.2010.16978.x
Jones H.G. & Vaughan R.A. (2010). Remote Sensing of Vegetation. Oxford University Press, Oxford.
Joshi M.M., Haberle R.M. & Reynolds R.T. (1997). Simulations of the atmospheres of synchronously rotating terrestrial planets orbiting M dwarfs: conditions for atmospheric collapse and the implications for habitability. Icarus 129, 450465.
Kaltenegger L. & Traub W.A. (2009). Transits of Earth-like planets. Astrophys. J. 698, 519527, doi: 10.1088/0004-637X/698/1/519
Kaltenegger L. et al. (2010). Deciphering spectral fingerprints of habitable exoplanets. Astrobiology 10(1), 89102.
Kasting J.F. (1993). Earth's early atmosphere. Science 259, 920926.
Kasting J.F. (1997). Habitable zones around lowmass stars and the search for extraterrestrial life. Origins Life. Evol. B 27, 291307.
Kasting J.F. & Howard M.T. (2006). Atmospheric composition and climate on the early earth. Phil. Trans. R. Soc. B 361, 17331742.
Kasting J.F., Whitmore D.P. & Reynolds R.T. (1993). Habitable zones around main sequence stars. Icarus 101, 108128.
Kiang N.Y. (2008). The color of plants on other worlds. Sci. Am. 298, 4855, doi: 10.1038/scientificamerican0408-48
Kiang N.G.Y., Siefert J., Govindjee G., Blankenship R.E. (2007a). Spectral signatures of photosynthesis. I. Review of earth organisms. Astrobiology 7, 222251.
Kiang N.Y., Segura A., Tinetti G., Blankenship R.E., Cohen M., Siefert J., Crisp D. & Meadows V. (2007b). Spectral signatures of photosynthesis. II. Coevolution with Other Stars and the Atmosphere on Extrasolar Worlds. Astrobiology 7, 252274.
Kim M-K. & Harwood C.S. (1991). Regulation of benzoate-CoA ligase in Rhodopseudomonas palustris . FEMS Microbiol. Lett. 83, 199203.
Kirk J.T.O. (2011). Light and Photosynthesis in Aquatic Systems, 3rd edn. Cambridge University Press, Cambridge.
Kite E.S., Gaidos E. & Manga M. (2011). Climate instability on tidally locked exoplanets. Astrophys. J. 743, 41, 30pp.
Klepac-Ceraj V., Hayes C.A., Gilhooly W.P., Lyons T.W., Kolter R. & Pearson A. (2012). Microbial diversity under extreme euxinaia: Mahoney Lake, Canada. Geobiology 10, 223235. doi: 10.1111/j.1472-4669.2012.00317.x
Kolber Z.S., Van Dover C.L., Niederman R.A. & Falkowski P.G. (2000). Bacterial photosynthesis in surface waters of the open ocean. Nature 407, 177179.
Komatsu Y., Umemura M., Shoji M., Kayanuma M., Yabana K. & Shiraishi K. (2015). Light absorption efficiencies of photosynthetic pigments: the dependence on spectral types of central stars. Int. J. Astrobiol. 14, 505510.
Kopparapu R.R., Ramirez R., Kasting J.F., Eymet V., Robinson T.D., Mahadevan S., Terrien R.C., Domagal-Goldman S., Meadows V. & Deshpande R. (2013). Habitable zones around main-sequence stars: new estimates. Astrophys. J. 765, 131, 16pp, doi: 10.1088/0004-637X/765/2/131
Kühl M. & Fenchel T. (2000). Bio-optical characteristics and the vertical distribution of photosynthetic pigments and photosynthesis in an artificial cyanobacterial mat. Microb. Ecol. 4, 94103.
Lammer H. (2007). Preface: M star planet habitability. Astrobiology 7, 2729. doi: 10.1089/ast.2006.0123.
Lammer H. et al. (2009). What makes a planet habitable? Astron. Astrophys. Rev. 17, 181249, doi: 10.1007/s00159-009-0019-z
Lange O.L., Kidron B.D., Budel B., Meyer A., Kilian E. & Abeliovich K.A. (1992). Taxonomic composition and photosynthetic characteristics of the ‘Biological Soil Crusts’ covering sand dunes in the Western Negev Desert. Funct. Ecol. 6, 519527.
Larimer F.W. et al. (2004). Complete genome sequence of the metabolically versatile photosynthetic bacterium Rhodopseudomonas palustris. Nat. Biotechnol. 22, 5561.
Larkum A.W.D. (2008). Evolution of the reaction centers and photosystems. In Primary Processes of Photosynthesis: Principles and Apparatus, vol. 2, ed. Rengler G., pp. 489521. Royal Society of Chemistry, Cambridge.
Larkum A.W.D. (2010). Limitations and prospects of natural photosynthesis for bioenergy production. Curr. Opin. Biotechnol. 21, 271276.
Larkum A.W.D. & Barrett J. (1983). Light harvesting processes in algae. Adv. Bot. Res. 10, 1219. Academic Press, New York.
Larsen H., Yocum C.S. & van Niel C.B. (1952). On the energetics of the photosynthesis in green sulphur bacteria. J. Gen. Physiol. 36, 161171, DOI: 10.1085/jgp.36.2.161
Léger A., Fontecave M., Labeyrie A., Samuel B., Demangeon O. & Valencias D. (2010). Is the presence of oxygen on an exoplanet a reliable biosignature? Astrobiology 11, 335341.
Littler M.M., Littler D.S., Blair S.M. & Norris J.N. (1985). Deepest known plant life discovered on an uncharted seamount. Science 227, 5760.
Littler M.M., Littler D.S., Blair S.M. & Norris J.N. (1986). Deep-water plant communities from an uncharted seamount off San Salvador Island, Bahamas: distribution, abundance, and primary productivity. Deep Sea Res. A, Oceanogr. Res. Pap. 33, 881892.
Luger R. & Barnes R. (2015). Extreme water loss and abiotic O2 buildup on planets throughout the habitable zones of M dwarfs. Astrobiology 15, 119143.
Lyons T.W. & Reinhard C.T. (2009). An early productive ocean unfit for aerobics? Proc. Nat. Acad. Sci. USA 106, 1804518046, doi: 10.1073_pnas.0910345106
Madigan M.T. (2003). Anoxygenic phototrophic bacteria from extreme environments. Photosynth. Res. 76, 1572003.
McCree K.J. (1972). The Action spectrum, absorptance and quantum yield of photosynthesis in crop plants. Agr. Meteorol. 9, 191216.
McLachlan J. (1973). Growth media – marine. In Handbook of Phycological Methods: Culture Methods and Growth Measurements, ed. Stein J.R., pp. 2551. Cambridge University Press, Cambridge, UK.
Mikucki J.A. & Priscu J.C. (2007). Bacterial diversity associated with Blood Falls, a subglacial outflow from the Taylor Glacier, Antarctica. Appl. Environ. Microb. 73, 40294039.
Miyashita H., Ikemoto H., Kurano N., Miyachi S. & Chihara M. (2003). Acaryochloris marina Gen. et Sp. Nov. (Cyanobacteria), an oxygenic photosynthetic prokaryote containing Chl d as a major pigment. J. Phycol. 39, 12471253.
Neutzling O., Imhoff J.F. & Trüper H.G. (1984). Rhodopseudomonas adriatica sp. nov., a new species of the Rhodospirillaceae, dependent on reduced sulphur compounds. Arch. Microbiol. 137, 256261.
Parkin T.B. & Brock T.D. (1980). Photosynthetic bacterial production in lakes: the effects of light intensity. Limnol. Oceanogr. 25, 711718.
Pettersen B.R. & Hawley S.L. (1989). A spectroscopic survey of red dwarf flare stars. Astron. Astrophys. 217, 187200.
Quintana E.V. et al. (2014). An Earth-sized planet in the habitable zone of a cool star. Science 344, 277280.
Ramirez R.M., Kopparapu R., Zuggers M.E., Robinson T.D., Freedman R. & Kasting J.F. (2013). Warming early Mars with CO2 and H2 . Nat. Geosci 7, 5963
Raven J.A. (1977). The evolution of vascular land plants in relation to supracellular transport processes. Adv. Bot. Res. 5, 153219.
Raven J.A. (2007). Photosynthesis in watercolours. Nature 448, 418.
Raven J.A. (2009). Contributions of anoxygenic and oxygenic phototrophy and chemolithotrophy to carbon and oxygen fluxes in aquatic environments. Aquat. Microb. Ecol. 56, 177192, DOI: 10.3354/ame01315
Raven J.A. & Cockell C.S. (2006). Influence on photosynthesis of starlight, moonlight, planetlight, and light pollution (reflections on photosynthetically active radiation in the universe). Astrobiology 6, 668675.
Raven J.A. & Donnelly S. (2013). Brown dwarfs and black smokers. The potential for photosynthesis using the radiation from low-temperature black bodies. In Habitability of Other Planets and Satellites. Volume 28 of Cellular Origin, Life in Extreme Habitats and Astrobiology, ed. De Vera J.-P. & Seckbach J., pp. 267284. Springer, Dordrecht. DOI: 10.1007/978-94-007-6546-7_15
Raven J.A., Kilber J.E. & Beardall J. (2000). Put out the light, and then put out the light. J. Mar. Biol. Assoc. UK 80, 125.
Ribas I. et al. (2016). The habitability of Proxima Centauri b. I. Irradiation, rotation and volatile inventory from formation to the present. Astron. Astrophys. arXiv:1608.06813v2 [Astro-ph.EP], accepted September 2016.
Ribas I., Gregg M.D., Boyajian T.S. & Bolmont E. (2017). The full spectral radiative properties of Proxima centauri. Astron. Astrophys. 596, A111
Ritchie R.J. (2008). Fitting light saturation curves measured using PAM fluorometry. Photosynth. Res. 96, 201215.
Ritchie R.J. (2010). Modelling photosynthetically active radiation and maximum potential gross photosynthesis. Photosynthetica 48, 596609.
Ritchie R.J. (2012). Photosynthesis in the blue water lily (Nymphaea caerulea Saligny) using PAM fluorometry. Int. J. Plant Sci. 173, 124136.
Ritchie R.J. (2013). The use of solar radiation by a photosynthetic bacterium living as a mat or in a shallow pond or flatbed reactor. Photochem. Photobiol. 89, 11431162, doi: 10.1111/php.12124.
Ritchie R.J. (2014). Photosynthesis in an Encrusting Lichen (Dirinaria picta (Sw.) Schaer.ex Clem., Physiaceae) and Its Symbiont, Trebouxia sp, using PAM Fluorometry. Int. J. Plant Sci. 175, 450466.
Ritchie R.J. & Larkum A.W.D. (2013). Modelling photosynthesis in shallow algal production ponds. Photosynthetica 50, 481500.
Ritchie R.J. & Mekjinda N. (2015). Measurement of photosynthesis using PAM technology in a purple sulphur bacterium Thermochromatium tepidum (Chromatiaceae). Photochem. Photobiol. 91, 350358, doi: 10.1111/php.12413
Ritchie R.J. & Runcie J.W. (2013). Measurement of the photosynthetic electron transport rate in an anoxygenic photosynthetic bacterium Afifella (Rhodopseudomonas) salina using PAM fluorometry. Photochem. Photobiol. 89, 370383.
Ritchie R.J. & Runcie R.W. (2014). A portable reflectance–absorptance–transmittance (RAT) meter for vascular plant leaves. Photosynthetica 52, 614626, DOI: 10.1007/s11099-014-0069-y
Rothschild L.J. (2008). The evolution of photosynthesis. Again? Philos. Trans. R. Soc. B 363, 27872801.
Runcie J.W., Gurgel C.F. & Mcdermid K.J. (2008). In situ photosynthetic rates of tropical marine macroalgae at their lower depth limit. Eur. J. Phycol. 43, 377388.
Rushby A.J., Claire M.W., Osborn H. & Watson A.J. (2013). Habitable zone lifetimes of exoplanets around main sequence stars. Astrobiology 13, 833849, DOI: 10.1089/ast.2012.0938
Scalo J. et al. (2007). M stars as targets for terrestrial exoplanet searches and biosignature detection. Astrobiology 7, 85166.
Schindler T.L. & Kasting J.F. (2000). Synthetic spectra of simulated terrestrial atmospheres containing possible biomarker gases. Icarus 145, 262271, doi: 10.1006/icar.2000.6340
Schliep M., Cavigliasso G., Quinnell R.G., Stranger R. & Larkum A.W.D. (2013). Formyl group modification of chlorophyll a: a major evolutionary mechanism in oxygenic photosynthesis. Plant Cell Environ. 36, 521527.
Schopf J.W. (2011). The paleobiological record of photosynthesis. Photosynth. Res. 107, 87101.
Schott J., Griffin B.M. & Schink B. (2010). Anaerobic phototrophic nitrite oxidation by Thiocapsa sp. strain KS1 and Rhodopseudomonas sp. strain LQ17. Microbiology 156, 24282437, doi: 10.1099/mic.0.036004-0
Schwieterman E.W., Cockell C.S. & Meadows V.S. (2015). Nonphotosynthetic pigments as potential biosignatures. Astrobiology 15, 341361.
Seager S. (2014). The future of spectroscopic life detection on exoplanets. Proc. Nat. Acad. Sci. USA 111, 1263412640.
Seager S. & Bains W. (2015). The search for signs of life on exoplanets at the interface of chemistry and planetary science. Sci. Adv. 1, e1500047, 11pp
Seager S., Turner E.L., Schafer J. & Ford E.B. (2005). Vegetation's red edge: a possible spectroscopic biosignature of extraterrestrial plants. Astrobiology 5, 372390.
Seager S., Bains W. & Petkowski J.J. (2016). Toward a list of molecules as potential biosignature gases for the search for life on exoplanets and applications to terrestrial biochemistry. Astrobiology 16, 465485, doi: 10.1089/ast.2015.1404
Segura A., Krelove K., Kasting J.F., Sommerlatt D., Meadows V., Crisp D., Cohen M., Lawler E. (2003). Ozone concentrations and ultraviolet fluxes on Earth-like planets around other stars. Astrobiology 3, 689708.
Segura A., Kasting J.F., Meadows V., Cohen M., Scalo J., Crisp D., Butler R.A.H. & Tinetti G. (2005). Biosignatures from Earth-like planets around M dwarfs. Astrobiology 5, 706725.
Segura A., Walkowicz L.M., Meadows V., Kasting J. & Hawley S. (2010). The Effect of a Strong Stellar Flare on the Atmospheric Chemistry of an Earth-like Planet Orbiting an M Dwarf. Astrobiology 10, 751771.
Selsis F., Kasting J.F., Levrard B., Paillet J., Ribase I. & Delfosse X. (2007). Habitable planets around the star Gliese 581? Astron. Astrophys. 476, 13731387, doi: 10.1051/0004-6361:20078091.
SMARTS (2011). Simple Model of Atmospheric Radiative Transfer of Sunshine (SMARTS): (accessed 12 August 2011).
Smith R.C. & Baker K.S. (1981). Optical properties of the clearest natural waters (200–800 nm). Appl. Opt. 20, 177184.
Sojka G.A., Freeze H.H. & Gest H. (1970). Quantitative estimation of bacteriochlorophyll in situ. Arch. Biochem. Biophys. 136, 578580.
Stomp M., Huisman J., Stahl L.J. & Matthijs C.P. (2007). Winogradsky review: colorful niches of phototrophic microorganisms shaped by vibrations of the water molecule. ISME J. 1, 271282.
Stüeken E.E., Catling D.C. & Buick R. (2012). Contributions to late Archaean sulphur cycling by life on land. Nat. Geosci. 5, 722725.
Tarter J.C. et al. (2007). A reappraisal of the habitability of planets around M dwarf stars. Astrobiology 7, 3065.
Thomas D.N. (2005). Photosynthetic microbes in freezing deserts. Trends Microbiol. 13, 8788.
Tice M.M. & Lowe D.R. (2004). Photosynthetic microbial mats in the 3,416-Myr-old ocean. Nature 431, 549552.
Tinetti G., Rashby S. & Yung Y.L. (2006). Detectability of Red-edge-shifted vegetation on terrestrial Planets Orbiting M Stars. Astrophys. J. 644, L129L132.
Trail D., Watson E.B. & Tailby N.D. (2011). The oxidation state of Hadean magmas and implications for early Earth's atmosphere. Nature 480, 7983.
Traub W.A. (2012). Terrestrial habitable-zone exoplanet frequency from Kepler. Astrophys. J. 745, 20, 10pp, doi: 10.1088/0004-637X/745/1/20
Turbet M., Leconte J., Selsis F., Bolmont E., Forget F., Ribas I., Raymond S.N. & Anglada-Escudé G. (2016). The habitability of Proxima Centauri b. II Possible climates and observability. Astron. Astrophys., arXiv:1608.06827v1 [Astro-ph.EP] 24 August 2016.
Turnbull M.C., Glassman T., Roberge A., Cash W., Noecker C., Lo A., Mason B., Oakley P. & Bally J. (2012). The search for habitable worlds: 1. The viability of a starshade mission. Publ. Astron. Soc. Pac. 124, 915, 418447, doi: 10.1086/666325
van Belle G.T. & von Braun K. (2009). Directly determined linear radii and effective temperatures of exoplanet host stars. Astrophys. J. 694, 10851098.
van Niel C.B. (1944). The culture, general physiology, morphology and classification of the non-sulphur purple and brown bacteria. Bacteriol. Rev. 8, 1118.
Vincent W.F., Rae R., Laurion I., Howard-Williams C. & Priscu J.C. (1998). Transparency of Antarctic ice-covered lakes to solar radiation. Limnol. Oceanogr. 43, 618624.
Vogt S.S., Butler R.P., Rivera E.J., Haghighipour N., Henry G.W. & Williamson M.W. (2010). The lick–carnegie exoplanet survey: a 3.1 M⊕ planet in the habitable zone of the nearby M3 V star gliese 581. Astrophys. J. 723, 954965, doi: 10.1088/0004-637X/723/1/954 C2010
von Bloh W., Cunz M., Schröder K-P., Bournama C. & Franck S. (2009). Habitability of super-Earth planets around other suns: models including red giant branch evolution. Astrobiology 9, 593602.
von Bloh W., Bounama C. & Franck S. (2010). Photosynthesis in the milky way. Plant Sci. 178, 485490.
von Paris P., Gebauer S., Godolt M., Rauer H. & Stracke B. (2011). Atmospheric studies of habitability in the Gliese 581 system. Astron. Astrophys. 532, A58, 4pp, doi: 10.1051/0004-6361/201016058
von Paris P., Hedelt P., Selsis F., Schreier F. & Trautmann T. (2013). Characterization of potentially habitable planets: retrieval of atmospheric and planetary properties from emission spectra. Astron. Astrophys. 551, A120, 13pp, doi: 10.1051/0004-6361/201220009
Vopel K. & Hawes I. (2006). Photosynthetic performance of benthic microbial mats in Lake Hoare, Antarctica. Limnol. Oceanogr. 51, 18011812.
Walker D. (1990). The use of the Oxygen Electrode and Fluorescence Probes in Simple Measurements of Photosynthesis. Robert Hill Institute, The University of Sheffield, UK.
Wilhelm C. & Jakob T. (2006). Uphill energy transfer from long-wavelength absorbing chlorophylls to PS II in Ostreobium sp. is functional in carbon assimilation. Photosynth. Res. 87, 323329. doi: 10.1007/s11120-005-9002-3
Williams D.M. & Pollard D. (2002). Earth-like worlds on eccentric orbits: excursions beyond the habitable zone. Int. J. Astrobiol. 1, 6169.
Wolstencroft R.D. & Raven J.A. (2002). Photosynthesis: likelihood of occurrence and possibility of detection on Earth-like planets. Icarus 157, 535548.
Zahnle K., Schaefer L. & Fegley B. (2011). Earth's earliest atmospheres. Cold Spring Harbour Perspectives in Biology, 2, a004895. doi: 10.1101/cshperspect.a004895
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? *


Type Description Title
Supplementary Materials

Ritchie supplementary material
Ritchie supplementary material 1

 Unknown (75 KB)
75 KB


Full text views

Total number of HTML views: 6
Total number of PDF views: 45 *
Loading metrics...

Abstract views

Total abstract views: 403 *
Loading metrics...

* Views captured on Cambridge Core between 18th July 2017 - 23rd November 2017. This data will be updated every 24 hours.