Sensitivity of organic matter decomposition to warming varies with its quality


Autoria(s): Conant, Richard T.; Drijber, Rhae A.; Haddix, Michelle L.; Parton, William J.; Paul, Eldor A.; Plante, Alain F.; Six, Johan; Steinweg, J. Megan
Data(s)

2008

Resumo

The relationship between organic matter (OM) lability and temperature sensitivity is disputed, with recent observations suggesting that responses of relatively more resistant OM to increased temperature could be greater than, equivalent to, or less than responses of relatively more labile OM. This lack of clear understanding limits the ability to forecast carbon (C) cycle responses to temperature changes. Here, we derive a novel approach (denoted Q(10-q)) that accounts for changes in OM quality during decomposition and use it to analyze data from three independent sources. Results from new laboratory soil incubations (labile Q(10-q)=2.1 +/- 0.2; more resistant Q(10-q)=3.8 +/- 0.3) and reanalysis of data from other soil incubations reported in the literature (labile Q(10-q)=2.3; more resistant Q(10-q)=3.3) demonstrate that temperature sensitivity of soil OM decomposition increases with decreasing soil OM lability. Analysis of data from a cross-site, field litter bag decomposition study (labile Q(10-q)=3.3 +/- 0.2; resistant Q(10-q)=4.9 +/- 0.2) shows that litter OM follows the same pattern, with greater temperature sensitivity for more resistant litter OM. Furthermore, the initial response of cultivated soils, presumably containing less labile soil OM (Q(10-q)=2.4 +/- 0.3) was greater than that for undisturbed grassland soils (Q(10-q)=1.7 +/- 0.1). Soil C losses estimated using this approach will differ from previous estimates as a function of the magnitude of the temperature increase and the proportion of whole soil OM comprised of compounds sensitive to temperature over that temperature range. It is likely that increased temperature has already prompted release of significant amounts of C to the atmosphere as CO2. Our results indicate that future losses of litter and soil C may be even greater than previously supposed.

Formato

application/pdf

Identificador

http://eprints.qut.edu.au/37766/

Publicador

Blackwell Publishing

Relação

http://eprints.qut.edu.au/37766/1/cona6136.pdf

DOI:10.1111/j.1365-2486.2008.01541.x

Conant, Richard T., Drijber, Rhae A., Haddix, Michelle L., Parton, William J., Paul, Eldor A., Plante, Alain F., Six, Johan, & Steinweg, J. Megan (2008) Sensitivity of organic matter decomposition to warming varies with its quality. Global Change Biology, 14(4), pp. 868-877.

Fonte

Institute for Sustainable Resources

Palavras-Chave #060200 ECOLOGY #decomposition, litter, soil carbon, temperature sensitivity
Tipo

Journal Article