caa a22 4500 605517142 CHVBK 20210128100718.0 cr unu---uuuuu 210128e20150301xx s 000 0 eng 10.1007/s10533-014-0054-3 doi (NATIONALLICENCE)springer-10.1007/s10533-014-0054-3 Minor stable carbon isotope fractionation between respired carbon dioxide and bulk soil organic matter during laboratory incubation of topsoil [Elektronische Daten] [D. Breecker, S. Bergel, M. Nadel, M. Tremblay, R. Osuna-Orozco, T. Larson, Z. Sharp] A common assumption in paleoenvironmental reconstructions using soils is that the carbon isotope composition of soil-respired CO2 is equivalent to the carbon isotope composition of bulk soil organic matter (SOM). However, the occurrence of a non-zero per mil carbon isotope enrichment factor between CO2 and SOM ( $$\varepsilon_{{{\text{CO}}_{ 2} - {\text{SOM}}}}$$ ε CO 2 - SOM ) during soil respiration is the most widely accepted explanation for the down-profile increase in SOM δ13C values commonly observed in well-drained soils. In order to shed light on this apparent discrepancy, we incubated soil samples collected from the top 2cm of soils with pure C3 vegetation and compared the δ13C values of soil-respired CO2 to the δ13C values of bulk SOM. Our results show near-zero $$\varepsilon_{{{\text{CO}}_{ 2} - {\text{SOM}}}}$$ ε CO 2 - SOM values (−0.3 to 0.4‰), supporting the use of paleosol organic matter as a proxy for paleo soil-respired CO2. Significantly more negative $$\varepsilon_{{{\text{CO}}_{ 2} - {\text{SOM}}}}$$ ε CO 2 - SOM values are required to explain the typical δ13C profiles of SOM in well-drained soils. Therefore our results also suggest that typical SOM δ13C profiles result from either (1) a process other than carbon isotope fractionation between CO2 and SOM during soil respiration or (2) $$\varepsilon_{{{\text{CO}}_{ 2} - {\text{SOM}}}}$$ ε CO 2 - SOM values that become increasingly negative as SOM matures. Springer International Publishing Switzerland, 2014 Soil nationallicence Organic matter nationallicence CO2 nationallicence Carbon isotopes nationallicence Incubation nationallicence Fractionation nationallicence Breecker D. The Department of Geological Sciences, The University of Texas at Austin, Austin, TX, USA aut Bergel S. The Department of Geological Sciences, The University of Texas at Austin, Austin, TX, USA aut Nadel M. The Department of Geological Sciences, The University of Texas at Austin, Austin, TX, USA aut Tremblay M. The Department of Geological Sciences, The University of Texas at Austin, Austin, TX, USA aut Osuna-Orozco R. Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA aut Larson T. The Department of Geological Sciences, The University of Texas at Austin, Austin, TX, USA aut Sharp Z. The Department of Earth and Planetary Sciences, The University of New Mexico, Albuquerque, NM, USA aut Biogeochemistry Springer International Publishing 123/1-2(2015-03-01), 83-98 0168-2563 123:1-2<83 2015 123 10533 https://doi.org/10.1007/s10533-014-0054-3 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10533-014-0054-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Breecker D. The Department of Geological Sciences, The University of Texas at Austin, Austin, TX, USA aut NATIONALLICENCE 700 1- Bergel S. The Department of Geological Sciences, The University of Texas at Austin, Austin, TX, USA aut NATIONALLICENCE 700 1- Nadel M. The Department of Geological Sciences, The University of Texas at Austin, Austin, TX, USA aut NATIONALLICENCE 700 1- Tremblay M. The Department of Geological Sciences, The University of Texas at Austin, Austin, TX, USA aut NATIONALLICENCE 700 1- Osuna-Orozco R. Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA aut NATIONALLICENCE 700 1- Larson T. The Department of Geological Sciences, The University of Texas at Austin, Austin, TX, USA aut NATIONALLICENCE 700 1- Sharp Z. The Department of Earth and Planetary Sciences, The University of New Mexico, Albuquerque, NM, USA aut NATIONALLICENCE 773 0- Biogeochemistry Springer International Publishing 123/1-2(2015-03-01), 83-98 0168-2563 123:1-2<83 2015 123 10533