Soil carbon pool structure and temperature sensitivity inferred using CO2 and 13CO2 incubation fluxes from five Hawaiian soils

摘要: We measured respiration and δ13C values of respiredand soil carbon in long-term incubations soils from two forests andthree pastures along an altitudinal gradient Hawaii. CO2fluxes early the decreased rapidly, then stabilizedat approximately 20% initial for sevenmonths. suggest that rapid drop subsequent stabilizationof reflects a change dominant source theCO2 labile (active) to much more recalcitrantpools organic matter (SOM). Estimates active SOM weremade by integrating all respired excess thatattributable intermediate pool; thesevalues ranged 0.7–4.3% total C.δ13C pasturesoils showed older, forest-derived C contributed increasingfraction with time. Initial late-stagerespiration responded similarly changes temperature, suggestingthat is as sensitive temperature activefraction.