ISSN:
1573-515X
Keywords:
soil respiration
;
soil organic matter
;
decomposition
;
carbon-13
;
soil incubations
;
atmospheric CO2
;
Hawaii
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Geosciences
Notes:
Abstract We measured respiration and δ13C values of respiredand soil carbon in long-term incubations of soils from two forests andthree pastures along an altitudinal gradient in Hawaii. CO2fluxes early in the incubations decreased rapidly, and then stabilizedat approximately 20% of initial values for sevenmonths. We suggest that the rapid drop and subsequent stabilizationof respiration reflects a change in the dominant source of theCO2 from labile (active) to much more recalcitrantpools of soil organic matter (SOM). Estimates of active SOM weremade by integrating all of the carbon respired in excess of thatattributable to respiration of the intermediate SOM pool; thesevalues ranged from 0.7–4.3% of total soil C.δ13C values for carbon respired from the pasturesoils showed that older, forest-derived C contributed an increasingfraction of total soil respiration with time. Initial and late-stagerespiration responded similarly to changes in temperature, suggestingthat intermediate SOM is as sensitive to temperature as the activefraction.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1017942918708
