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Extreme enrichment in atmospheric 15 N 15 N.
- Source :
-
Science advances [Sci Adv] 2017 Nov 17; Vol. 3 (11), pp. eaao6741. Date of Electronic Publication: 2017 Nov 17 (Print Publication: 2017). - Publication Year :
- 2017
-
Abstract
- Molecular nitrogen (N <subscript>2</subscript> ) comprises three-quarters of Earth's atmosphere and significant portions of other planetary atmospheres. We report a 19 per mil (‰) excess of <superscript>15</superscript> N <superscript>15</superscript> N in air relative to a random distribution of nitrogen isotopes, an enrichment that is 10 times larger than what isotopic equilibration in the atmosphere allows. Biological experiments show that the main sources and sinks of N <subscript>2</subscript> yield much smaller proportions of <superscript>15</superscript> N <superscript>15</superscript> N in N <subscript>2</subscript> . Electrical discharge experiments, however, establish <superscript>15</superscript> N <superscript>15</superscript> N excesses of up to +23‰. We argue that <superscript>15</superscript> N <superscript>15</superscript> N accumulates in the atmosphere because of gas-phase chemistry in the thermosphere (>100 km altitude) on time scales comparable to those of biological cycling. The atmospheric <superscript>15</superscript> N <superscript>15</superscript> N excess therefore reflects a planetary-scale balance of biogeochemical and atmospheric nitrogen chemistry, one that may also exist on other planets.
Details
- Language :
- English
- ISSN :
- 2375-2548
- Volume :
- 3
- Issue :
- 11
- Database :
- MEDLINE
- Journal :
- Science advances
- Publication Type :
- Academic Journal
- Accession number :
- 29159288
- Full Text :
- https://doi.org/10.1126/sciadv.aao6741