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| Titel |
Substrate quality alters the microbial mineralization of added substrate and soil organic carbon |
| VerfasserIn |
S. Jagadamma, M. A. Mayes, J. M. Steinweg, S. M. Schaeffer |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 17 ; Nr. 11, no. 17 (2014-09-03), S.4665-4678 |
| Datensatznummer |
250117576
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| Publikation (Nr.) |
 copernicus.org/bg-11-4665-2014.pdf |
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| Zusammenfassung |
| The rate and extent of decomposition of soil organic carbon (SOC) is
dependent, among other factors, on substrate chemistry and microbial
dynamics. Our objectives were to understand the influence of substrate
chemistry on microbial decomposition of carbon (C), and to use model fitting
to quantify differences in pool sizes and mineralization rates. We conducted
an incubation experiment for 270 days using four uniformly labeled 14C
substrates (glucose, starch, cinnamic acid and stearic acid) on four
different soils (a temperate Mollisol, a tropical Ultisol, a sub-arctic
Andisol, and an arctic Gelisol). The 14C labeling enabled us to separate
CO2 respired from added substrates and from native SOC. Microbial gene
copy numbers were quantified at days 4, 30 and 270 using quantitative
polymerase chain reaction (qPCR). Substrate C respiration was always higher
for glucose than other substrates. Soils with cinnamic and stearic acid lost
more native SOC than glucose- and starch-amended soils. Cinnamic and stearic
acid amendments also exhibited higher fungal gene copy numbers at the end of
incubation compared to unamended soils. We found that 270 days were
sufficient to model the decomposition of simple substrates (glucose and
starch) with three pools, but were insufficient for more complex substrates
(cinnamic and stearic acid) and native SOC. This study reveals that substrate
quality exerts considerable control on the microbial decomposition of newly added and
native SOC, and demonstrates the need for multi-year incubation experiments
to constrain decomposition parameters for the most recalcitrant fractions of
SOC and complex substrates. |
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