Journal Article

FZJ-2015-05165

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png The effect of soil moisture, soil particle size, litter layer and carbonic anhydrase on the oxygen isotopic composition of soil-released CO $_{2}$

Von Sperber, C. ; Weiler, M. ; Brüggemann, N. (Corresponding author)FZJ*

2015
Wiley-Blackwell Oxford [u.a.]

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Please use a persistent id in citations: doi:10.1111/ejss.12241

Abstract: Soil respiration and photosynthesis are the two largest carbon dioxide (CO2) fluxes between terrestrial ecosystems and the atmosphere and, therefore, the dominant processes influencing the oxygen isotopic composition of atmospheric CO2. The characterization of temporal and spatial variations of plant and soil-related fluxes of different oxygen isotopologues of CO2 (12C16O2; 12C16O18O) is relevant to constraining the global carbon budget. The oxygen isotopic composition of soil-respired CO2 is controlled by its release rate, the degree of isotopic equilibrium with soil water and the diffusional transport of CO2. The hypothesis of this study was that, as well as soil moisture, the soil particle size, the presence of an organic litter layer and the enzyme carbonic anhydrase (CA) would have a significant impact on the oxygen isotopic composition of soil-released CO2. We tested this hypothesis with soil microcosm experiments on columns of medium and fine sand. Soil water content and soil texture influenced the isotopic composition of soil-released CO2 significantly. A litter layer had a significant effect on the isotopic composition of water vapour but not on CO2 released from soil. In the absence of CA, oxygen isotope equilibration between the CO2 invasion flux and soil water was insignificant, whereas in the presence of CA about 55% of the CO2 invading the soil exchanged oxygen isotopes with soil water. Our findings highlight the importance of small-scale variability of soil attributes for the oxygen isotopic composition of soil-released CO2 as well as the strong impact of CA activity in soils.

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Contributing Institute(s):

1. Agrosphäre (IBG-3)

Research Program(s):

1. 255 - Terrestrial Systems: From Observation to Prediction (POF3-255) (POF3-255)

Appears in the scientific report 2015

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Database coverage:
; BIOSIS Previews ; Current Contents - Agriculture, Biology and Environmental Sciences ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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