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The role of N2 as a Geo-Biosignature for the Detection and Characterization of Earth-like Habitats

Lammer, H and Spross, L. and Grenfell, John Lee and Scherf, M. and Fossati, L. and Lendl, M. and Cubillos, P. (2019) The role of N2 as a Geo-Biosignature for the Detection and Characterization of Earth-like Habitats. Astrobiology, 19 (7), pp. 927-950. Mary Ann Liebert Inc.. doi: 10.1089/ast.2018.1914. ISSN 1531-1074.

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Official URL: https://www.liebertpub.com/doi/pdf/10.1089/ast.2018.1914


Since the Archean, N2 has been a major atmospheric constituent in Earth’s atmosphere. Nitrogen is an essential element in the building blocks of life; therefore, the geobiological nitrogen cycle is a fundamental factor in the long-term evolution of both Earth and Earth-like exoplanets. We discuss the development of Earth’s N2 atmosphere since the planet’s formation and its relation with the geobiological cycle. Then we suggest atmospheric evolution scenarios and their possible interaction with life-forms: first for a stagnant-lid anoxic world, second fora tectonically active anoxic world, and third for an oxidized tectonically active world. Furthermore, we discuss a possible demise of present Earth’s biosphere and its effects on the atmosphere. Since life-forms are the most efficient means for recycling deposited nitrogen back into the atmosphere at present, they sustain its surface partial pressure at high levels. Also, the simultaneous presence of significant N2 and O2 is chemically incompatible in an atmosphere over geological timescales. Thus, we argue that an N2-dominated atmosphere in combination with O2 on Earth-like planets within circumstellar habitable zones can be considered as a geo-biosignature. Terrestrial planets with such atmospheres will have an operating tectonic regime connected with an aerobic biosphere, whereas other scenarios in most cases end up with a CO2-dominated atmosphere. We conclude with implications for the search for life on Earth-like exoplanets inside the habitable zones of M to K stars.

Item URL in elib:https://elib.dlr.de/127817/
Document Type:Article
Title:The role of N2 as a Geo-Biosignature for the Detection and Characterization of Earth-like Habitats
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Lammer, HSpace Research Institute, Austrian Academy of SciencesUNSPECIFIED
Spross, L.Spa. Res. Inst., GrazUNSPECIFIED
Scherf, M.Space Research Institute, Austrian Academy of Sciences, Graz, AustriaUNSPECIFIED
Fossati, L.Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042, Graz, AustriaUNSPECIFIED
Lendl, M.Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, 8042 Graz, AustriaUNSPECIFIED
Cubillos, P.Spa. Res. Inst., GrazUNSPECIFIED
Date:July 2019
Journal or Publication Title:Astrobiology
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:Yes
Page Range:pp. 927-950
Publisher:Mary Ann Liebert Inc.
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Space Exploration
DLR - Research theme (Project):R - Projekt COROT Beteiligung (old)
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Extrasolar Planets and Atmospheres
Deposited By: Gebauer, Stefanie
Deposited On:02 Dec 2019 13:16
Last Modified:20 Jan 2020 14:36

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