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| Titel |
Deep CO2 soil inhalation/exhalation in a carbonated semiarid steppe induced by atmospheric pressure fluctuations |
| VerfasserIn |
Enrique P. Sánchez-Cañete, Andrew S. Kowalski, Penelope Serrano-Ortíz, Oscar Perez-Priego, Francisco Domingo |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250071871
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| Zusammenfassung |
| Knowledge of mechanisms and processes underlying in CO2 emissions soil-atmosphere is
essential to improve the understanding of the global carbon cycle. The main abiotic driver in
the CO2 exchange is soil ventilation. This advective transport through porous media has been
correlated with quasi-static pressure (p) gradients and turbulent winds. Here we examine the
variations in the subterranean CO2 molar fraction (Ïc) over two years within a vertical profile
(1.5 m), as influenced by changes in synoptic pressure in a semiarid ecosystem.
We show why the increases-decreases registered in Ïc are not due to biological
factors.
This study reveals that variations in the deep Ïc (1.5 m depth) are due predominantly to
static pressure variations and not to wind or biological influences. Within a few
hours, deep Ïc can be increased or decreased fivefold showing a pattern with two
maxima-minima per day, due to pressure oscillations caused by atmospheric tides. By
contrast, shallow Ïc (0.15 m depth) has only a one maximum-minimum per day influenced
by biological factors as soil water content and soil temperature but also affected by winds.
Future studies focused on determining the net ecosystem carbon balance should
not rely exclusively on Fick’s law to calculate soil CO2 effluxes from profile data. |
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