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Sensitivity of Biomarkers to Changes in Chemical Emissions in the Earth's Proterozoic Atmosphere

dc.contributor.authorGRENFELL, John Lee
dc.contributor.authorGEBAUER, Stefanie
dc.contributor.authorVON PARIS, P.
dc.contributor.authorGODOLT, Mareike
hal.structure.identifierObservatoire aquitain des sciences de l'univers [OASU]
hal.structure.identifierUniversité Sciences et Technologies - Bordeaux 1 [UB]
hal.structure.identifierLaboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
hal.structure.identifierLaboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
dc.contributor.authorHEDELT, P.
dc.contributor.authorPATZER, Beate
dc.contributor.authorSTRACKE, Barbara
hal.structure.identifierDLR Institute of Planetary Research
dc.contributor.authorRAUER, Heike
dc.date.created2010
dc.date.issued2011
dc.identifier.issn0019-1035
dc.description.abstractEnThe search for life beyond the Solar System is a major activity in exoplanet science. However, even if an Earth-like planet were to be found, it is unlikely to be at a similar stage of evolution as the modern Earth. It is therefore of interest to investigate the sensitivity of biomarker signals for life as we know it for an Earth-like planet but at earlier stages of evolution. Here, we assess biomarkers i.e. species almost exclusively associated with life, in present-day and in 10% present atmospheric level oxygen atmospheres corresponding to the Earth's Proterozoic period. We investigate the impact of proposed enhanced microbial emissions of the biomarker nitrous oxide, which photolyses to form nitrogen oxides which can destroy the biomarker ozone. A major result of our work is regardless of the microbial activity producing nitrous oxide in the early anoxic ocean, a certain minimum ozone column can be expected to persist in Proterozoic-type atmospheres due to a stabilising feedback loop between ozone, nitrous oxide and the ultraviolet radiation field. Atmospheric nitrous oxide columns were enhanced by a factor of 51 for the Proterozoic "Canfield ocean" scenario with 100 times increased nitrous oxide surface emissions. In such a scenario nitrous oxide displays prominent spectral features, so may be more important as a biomarker than previously considered in such cases. The run with "Canfield ocean" nitrous oxide emissions enhanced by a factor of 100 also featured additional surface warming of 3.5K. Our results suggest that the Proterozoic ozone layer mostly survives the changes in composition which implies that it is indeed a good atmospheric biomarker.
dc.language.isoen
dc.publisherElsevier
dc.subject.enAstrophysics
dc.subject.enEarth and Planetary Astrophysics
dc.title.enSensitivity of Biomarkers to Changes in Chemical Emissions in the Earth's Proterozoic Atmosphere
dc.typeArticle de revue
dc.identifier.doi10.1016/j.icarus.2010.09.015
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Planétologie et astrophysique de la terre [astro-ph.EP]
dc.subject.halPlanète et Univers [physics]/Astrophysique [astro-ph]/Planétologie et astrophysique de la terre [astro-ph.EP]
dc.identifier.arxiv1009.0439
bordeaux.journalIcarus
bordeaux.page81-88
bordeaux.volume211
bordeaux.issue1
bordeaux.peerReviewedoui
hal.identifierhal-00542390
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-00542390v1
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