Effluxed CO 2- 13C from sterilized and unsterilized treatments of a calcareous soil
Soil inorganic carbon (C) represents a substantial C pool in arid ecosystems, yet little data exist on the contribution of this pool to ecosystem C fluxes. A closed jar incubation study was carried out to test the hypothesis that CO 2- 13C production and response to sterilization would differ in a c...
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Published in | Soil biology & biochemistry Vol. 38; no. 7; pp. 1727 - 1733 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
Elsevier Ltd
2006
|
Subjects | |
Online Access | Get full text |
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Summary: | Soil inorganic carbon (C) represents a substantial C pool in arid ecosystems, yet little data exist on the contribution of this pool to ecosystem C fluxes. A closed jar incubation study was carried out to test the hypothesis that CO
2-
13C production and response to sterilization would differ in a calcareous (Mojave Desert) soil and a non-calcareous (Oklahoma Prairie) soil due to contributions of carbonate-derived CO
2. In addition to non-sterilized controls, soils were subjected to sterilization treatments (unbuffered HgCl
2 addition for Oklahoma soil and unbuffered HgCl
2 addition, buffered HgCl
2 addition, and autoclaving for Mojave Desert soil) to decrease biotic respiration and more readily measure abiotic CO
2 flux. Temperature and moisture treatments were also included with sterilization treatments in a factorial design.
The rate of CO
2 production in both soils was significantly decreased (36–87%) by sterilization, but sterilization treatments differed in effectiveness. Sterilization had no significant effect on effluxed CO
2-
13C values in the non-calcareous Oklahoma Prairie soil and autoclaved Mojave Desert soil as compared to their respective non-sterilized controls. However, sterilization significantly altered CO
2-
13C values in Mojave Desert soil HgCl
2 sterilization treatments (both buffered and non-buffered). Plots of 1/CO
2 versus CO
2-δ
13C (similar to Keeling plots) indicated that the source CO
2-δ
13C value of the Oklahoma Prairie soil treatments was similar to the δ
13C value of soil organic matter [(SOM); −17.76‰ VPDB] whereas the source for the (acidic) unbuffered-HgCl
2 sterilized Mojave Desert soil was similar to the δ
13C value of carbonates (−0.93‰ VPDB). The source CO
2-δ
13C value of non-sterilized and autoclaved (−18.4‰ VPDB) Mojave Desert soil treatments was intermediate between SOM (−21.43‰ VPDB) and carbonates and indicates up to 13% of total C efflux may be from abiotic sources in calcareous soils. |
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ISSN: | 0038-0717 1879-3428 |
DOI: | 10.1016/j.soilbio.2005.11.028 |