Relationships among forest soil C isotopic composition, partitioning, and turnover times
- ORNL
The purpose of this research was to test the hypothesis that vertical enrichment of soil {delta}{sup 13}C values is related to rates of soil C turnover in undisturbed, mature forest ecosystems. Soil C and N were measured at nine sites along an altitudinal gradient in the southern Appalachian Mountains (Tennessee and North Carolina, USA). Measurements indicated greater labile and total soil C stocks with increasing altitude. Laboratory incubations (3 days) of rewetted, air-dry soils indicated potential soil C mineralization ({micro}g CO{sub 2} produced {center_dot} g{sup -1} soil C) declined with elevation. A principal component analysis indicated N availability increased with altitude. At each site, there was a significant relationship between {delta}{sup 13}C and log-transformed C concentrations in the soil profile (30 cm deep). Enrichment factors ({var_epsilon}) from the Rayleigh equation were also equally useful for describing soil {delta}{sup 13}C profiles at each site. Soil C partitioning and turnover times along the gradient were correlated with {sup 13}C-enrichment factors. Greater rates of change in {delta}{sup 13}C through the soil profile were correlated with faster soil C turnover. Environmental factors, soil C partitioning, and the rate of vertical change in soil {sup 13}C abundance are interrelated such that {delta}{sup 13}C measurements are a potential indicator of C dynamics in undisturbed forest soils.
- Research Organization:
- Oak Ridge National Laboratory (ORNL); Oak Ridge National Environmental Research Park
- Sponsoring Organization:
- SC USDOE - Office of Science (SC)
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 978237
- Journal Information:
- Canadian Journal of Forest Research, Journal Name: Canadian Journal of Forest Research Journal Issue: 9 Vol. 36; ISSN CJFRAR; ISSN 0045-5067
- Country of Publication:
- United States
- Language:
- English
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