Changes in the O2/N2 ratio of the atmosphere during recent decades reflected in the composition of air in the firn at Vostok Station, Antarctica

M. L. Bender, Todd Anthony Sowers, J. ‐M Barnola, J. Chappellaz

Research output: Contribution to journalArticle

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Abstract

Samples of air at various depths in firn were collected at Vostok Station, Antarctica, and analyzed for δ15N of N2, O2/N2 ratio, and CO2. The ultimate objective of this work is to constrain the recent rate of the atmospheric [O2] decrease, thereby providing a direct experimental constraint on net CO2 fluxes into the ocean and the land biosphere. δ15N increases with depth, because of gravitational enrichment, at approximately the rate predicted by the barometric equation. Gravitationally corrected CO2 decreases with depth to 308 ppmV at 101.9 m depth, because deeper air is older and less contaminated with anthropogenic CO2. The gravitationally corrected O2/N2 ratio increases with depth mainly because burning fossil fuel consumes O2. Samples in the top 20 m of the firn have anomalously high CO2 concentrations and anomalously low O2/N2 ratios. Samples below 96.2 m depth have anomalously high O2/N2 ratios. Between 30 and 96.2 m depth, the gravitationally corrected increase in the O2/N2 ratio is nearly equal to that computed from the rate of O2 consumption by combustion of fossil fuels. Our results indicate that the rate of anthropogenic O2 consumption can be accurately constrained by future firn air studies.

Original languageEnglish (US)
Pages (from-to)189-192
Number of pages4
JournalGeophysical Research Letters
Volume21
Issue number3
DOIs
StatePublished - Jan 1 1994

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firn
Antarctic regions
stations
atmospheres
atmosphere
air
fossil fuels
fossil fuel
biosphere
Antarctica
station
oceans
combustion
rate
ocean

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Earth and Planetary Sciences(all)

Cite this

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title = "Changes in the O2/N2 ratio of the atmosphere during recent decades reflected in the composition of air in the firn at Vostok Station, Antarctica",
abstract = "Samples of air at various depths in firn were collected at Vostok Station, Antarctica, and analyzed for δ15N of N2, O2/N2 ratio, and CO2. The ultimate objective of this work is to constrain the recent rate of the atmospheric [O2] decrease, thereby providing a direct experimental constraint on net CO2 fluxes into the ocean and the land biosphere. δ15N increases with depth, because of gravitational enrichment, at approximately the rate predicted by the barometric equation. Gravitationally corrected CO2 decreases with depth to 308 ppmV at 101.9 m depth, because deeper air is older and less contaminated with anthropogenic CO2. The gravitationally corrected O2/N2 ratio increases with depth mainly because burning fossil fuel consumes O2. Samples in the top 20 m of the firn have anomalously high CO2 concentrations and anomalously low O2/N2 ratios. Samples below 96.2 m depth have anomalously high O2/N2 ratios. Between 30 and 96.2 m depth, the gravitationally corrected increase in the O2/N2 ratio is nearly equal to that computed from the rate of O2 consumption by combustion of fossil fuels. Our results indicate that the rate of anthropogenic O2 consumption can be accurately constrained by future firn air studies.",
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Changes in the O2/N2 ratio of the atmosphere during recent decades reflected in the composition of air in the firn at Vostok Station, Antarctica. / Bender, M. L.; Sowers, Todd Anthony; Barnola, J. ‐M; Chappellaz, J.

In: Geophysical Research Letters, Vol. 21, No. 3, 01.01.1994, p. 189-192.

Research output: Contribution to journalArticle

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AU - Chappellaz, J.

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AB - Samples of air at various depths in firn were collected at Vostok Station, Antarctica, and analyzed for δ15N of N2, O2/N2 ratio, and CO2. The ultimate objective of this work is to constrain the recent rate of the atmospheric [O2] decrease, thereby providing a direct experimental constraint on net CO2 fluxes into the ocean and the land biosphere. δ15N increases with depth, because of gravitational enrichment, at approximately the rate predicted by the barometric equation. Gravitationally corrected CO2 decreases with depth to 308 ppmV at 101.9 m depth, because deeper air is older and less contaminated with anthropogenic CO2. The gravitationally corrected O2/N2 ratio increases with depth mainly because burning fossil fuel consumes O2. Samples in the top 20 m of the firn have anomalously high CO2 concentrations and anomalously low O2/N2 ratios. Samples below 96.2 m depth have anomalously high O2/N2 ratios. Between 30 and 96.2 m depth, the gravitationally corrected increase in the O2/N2 ratio is nearly equal to that computed from the rate of O2 consumption by combustion of fossil fuels. Our results indicate that the rate of anthropogenic O2 consumption can be accurately constrained by future firn air studies.

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