A multi-decade history of soil carbon turnover along a temperature gradient
- Stanford Univ., CA (United States) Univ. of California, Irvine (United States)
We used an altitudinal gradient on the northeast flank of Mauna Kea Volcano, island of Hawaii to examine the effects of temperature on soil carbon turnover and stabilization. The gradient consists of C[sub 3] rainforest in parallel to C[sub 4] pastures converted from this forest several decades ago. Sites with little variation in rainfall or vegetation type were chosen on volcanic ash soils of similar ages. We obtained [delta][sup 13]C and [Delta][sup 14]C values for bulk soils and [delta][sup 13]C values for CO[sub 2] evolved in the field and from microbial fumigations. We constructed an isotope dilution model that uses the isotope data along with data on net primary productivity and total soil carbon to estimate relative pool sizes of highly recalcitrant [open quotes]passive[close quotes] and more labile [open quotes]non-passive[close quotes] soil carbon. Results of this model show that decomposition rates for carbon turning over at annual to decadal time scales increase with increasing temperature in a linear to saturating fashion. This response differs from the exponential relationships reported in numerous studies of litter decomposition and/or soil respiration. If soil carbon turnover as a whole is not an exponential function of temperature, then soils would be far less likely to be a net source of atmospheric CO[sub 2] in a warmer climate.
- OSTI ID:
- 6143231
- Report Number(s):
- CONF-930798--
- Journal Information:
- Bulletin of the Ecological Society of America; (United States), Journal Name: Bulletin of the Ecological Society of America; (United States) Vol. 74:2; ISSN BECLAG; ISSN 0012-9623
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
540220* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
CARBON
CARBON COMPOUNDS
CARBON CYCLE
CARBON DIOXIDE
CARBON OXIDES
CARBON SOURCES
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
CLIMATIC CHANGE
DECOMPOSITION
DEVELOPED COUNTRIES
ECOLOGICAL CONCENTRATION
ELEMENTS
FORESTS
GREENHOUSE EFFECT
HAWAII
ISOTOPE APPLICATIONS
ISOTOPE DILUTION
LEVELS
MATHEMATICAL MODELS
MATTER
MONITORING
NONMETALS
NORTH AMERICA
ORGANIC MATTER
OXIDES
OXYGEN COMPOUNDS
PASTURES
PRODUCTIVITY
SOIL CHEMISTRY
SOILS
TEMPERATURE DEPENDENCE
TEMPERATURE MONITORING
TRACER TECHNIQUES
USA