TY - JOUR

T1 - An isotopic method for testing the influence of leaf litterquality on carbon fluxes during decomposition

AU - Rubino, Mauro

PY - 2007

Y1 - 2007

N2 - During microbial breakdown of leaf litter afraction of the C lost by the litter is not released to theatmosphere as CO2 but remains in the soil as microbialbyproducts. The amount of this fraction and the factorsinfluencing its size are not yet clearly known. We performeda laboratory experiment to quantify the flow of Cfrom decaying litter into the soil, by means of stable Cisotopes, and tested its dependence on litter chemicalproperties. Three sets of 13C-depleted leaf litter (Liquidambarstyraciflua L., Cercis canadensis L. and Pinus taedaL.) were incubated in the laboratory in jars containing 13Cenrichedsoil (i.e. formed C4 vegetation). Four jars containingsoil only were used as a control. Litter chemicalproperties were measured using thermogravimetry (Tg) andpyrolysis-gas chromatography/mass spectrometry-combustioninterface-isotope ratio mass spectrometry (Py-GC/MS-C-IRMS). The respiration rates and the d13C of therespired CO2 were measured at regular intervals. After8 months of incubation, soils incubated with both L. styracifluaand C. canadensis showed a significant change ind13C (d13Cfinal = 20.2 ± 0.4% and 19.5 ± 0.5%,respectively) with respect to the initial value (d13Cinitial =17.7 ± 0.3%); the same did not hold for soil incubatedwith P. taeda (d13Cfinal:18.1 ± 0.5%). The percentagesof litter-derived C in soil over the total C loss were notstatistically different from one litter species to another.This suggests that there is no dependence of the percentageof C input into the soil (over the total C loss) on litterquality and that the fractional loss of leaf litter C isdependent only on the microbial assimilation efficiency.The percentage of litter-derived C in soil was estimatedto be 13 ± 3% of total C loss

AB - During microbial breakdown of leaf litter afraction of the C lost by the litter is not released to theatmosphere as CO2 but remains in the soil as microbialbyproducts. The amount of this fraction and the factorsinfluencing its size are not yet clearly known. We performeda laboratory experiment to quantify the flow of Cfrom decaying litter into the soil, by means of stable Cisotopes, and tested its dependence on litter chemicalproperties. Three sets of 13C-depleted leaf litter (Liquidambarstyraciflua L., Cercis canadensis L. and Pinus taedaL.) were incubated in the laboratory in jars containing 13Cenrichedsoil (i.e. formed C4 vegetation). Four jars containingsoil only were used as a control. Litter chemicalproperties were measured using thermogravimetry (Tg) andpyrolysis-gas chromatography/mass spectrometry-combustioninterface-isotope ratio mass spectrometry (Py-GC/MS-C-IRMS). The respiration rates and the d13C of therespired CO2 were measured at regular intervals. After8 months of incubation, soils incubated with both L. styracifluaand C. canadensis showed a significant change ind13C (d13Cfinal = 20.2 ± 0.4% and 19.5 ± 0.5%,respectively) with respect to the initial value (d13Cinitial =17.7 ± 0.3%); the same did not hold for soil incubatedwith P. taeda (d13Cfinal:18.1 ± 0.5%). The percentagesof litter-derived C in soil over the total C loss were notstatistically different from one litter species to another.This suggests that there is no dependence of the percentageof C input into the soil (over the total C loss) on litterquality and that the fractional loss of leaf litter C isdependent only on the microbial assimilation efficiency.The percentage of litter-derived C in soil was estimatedto be 13 ± 3% of total C loss

U2 - 10.1007/s00442-007-0815-y

DO - 10.1007/s00442-007-0815-y

M3 - Journal article

C2 - 17665218

JO - Oecologia

JF - Oecologia

SN - 0029-8519

ER -