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Title (Primary) Can the labile carbon contribute to carbon immobilization in semiarid soils? Priming effects and microbial community dynamics
Author Bastida, F.; Torres, I.F.; Hernández, T.; Bombach, P.; Richnow, H.H.; García, C.
Journal Soil Biology & Biochemistry
Year 2013
Department ISOBIO
Volume 57
Page From 892
Page To 902
Language englisch
Keywords Semiarid soil; Carbon cycling; Glucose; Priming effect; Stable isotope probing; Phospholipid fatty acids
UFZ wide themes ru3
Abstract Tracer experiments with isotopic-enriched carbon compounds can provide information regarding the carbon cycling in semiarid soils. We studied priming effects and microbial utilization of glucose as an example of bioavailable labile molecule in the carbon cycle of a semiarid soil. The soil, which has low content of total organic carbon (5.0 g kg−1), was amended with U13C-glucose (99 atom %) at concentration of 75 μg C g−1 soil (LD) or 300 μg C g−1 soil (HD). Glucose-derived carbon remained in soil after two months of incubation. The percentage of residual carbon stabilized was greater in LD with 40% of the initial 13C added compared to 30% of the initial 13C added in the HD. Comparison of 13C content in water- and sodium-pyrophosphate extracts pointed to a significant humification of up to 2.4% of the initial 13C-glucose. Glucose was subjected to an intense mineralization in the first 17-days of 22.8% and 40.94% for the LD and HD, respectively. The stable isotope probing (SIP) of phospholipid fatty acids (PLFAs) by gas-chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) showed that bacteria dominated glucose metabolism in comparison to fungi. Gram-negative populations were initially more involved in glucose assimilation than Gram-positive bacteria. In the fatty acids fraction, up to 95% of the 13C was predominantly found in fatty acids typical for Gram-negative bacteria. However, after 4 and 17 days the 13C-enrichment in Gram-positive biomarkers increased. The mineralization of soil organic matter triggered by glucose additions was more intense in HD (3.6% of soil TOC) than LD (1.0% of soil TOC) and reached the highest level after 4 days in HD. Priming was controlled by Gram-negative populations but fungi and, particularly actinobacteria played an important role in latter steps. Our data indicated that the intense metabolism of SOM due to priming phenomena compromises the potential carbon sequestration in this semiarid soil amended with glucose.
Persistent UFZ Identifier
Bastida, F., Torres, I.F., Hernández, T., Bombach, P., Richnow, H.H., García, C. (2013):
Can the labile carbon contribute to carbon immobilization in semiarid soils? Priming effects and microbial community dynamics
Soil Biol. Biochem. 57 , 892 - 902