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| Titel |
A large fraction of soil respiration is not exchanged with the atmosphere through the CO2 effluxes |
| VerfasserIn |
Enrique P. Sánchez-Cañete, Greg A. Barron-Gafford, Jon Chorover |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250142593
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| Publikation (Nr.) |
 EGU/EGU2017-6233.pdf |
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| Zusammenfassung |
| Vertical soil CO2 efflux from soil (Fsoil) is often considered equal to soil CO2 production
(Rsoil), and the two terms are used interchangeably. However, a considerable fraction of the
CO2 produced can be lost due to a host of different processes, including dissolution in water
and soil chemical reactions. The ratio between CO2 efflux / O2 influx, known as the apparent
respiratory quotient (ARQ), allows one to estimate these CO2 losses from Rsoil. Here we
present the first study using continuous ARQ estimates to evaluate annual CO2 losses of
carbon produced from Rsoil.
The field site is a semi-arid conifer forest located at 2573 m a.s.l. in the Santa Catalina
Mountains, Tucson, Arizona. Three instrumented soil pedons were installed to measure O2
and CO2 molar fraction, temperature and humidity at 10, 30 and 60 cm depths. We found that
1/3 of Rsoil was emitted directly to the atmosphere and 2/3 of Rsoil was removed by
non-biological processes. These losses could be mainly explained by chemical reactions
involving carbonic acid, and to a lesser extent by simple CO2 dissolution in water.
Therefore, having better estimates of Rsoil is key to understanding the true influence of
aboveground production on Rsoil and other connected processes within the critical zone. |
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