TY  - JOUR
AU  - Marcel, Lorenz
AU  - Hofmann, Diana
AU  - Steffen, Bernhard
AU  - Fischer, Klaus
AU  - Thiele-Bruh, Sören
TI  - The molecular composition of extractable soil microbial compounds andtheir contribution to soil organic matter vary with soil depth andtree species
JO  - The science of the total environment
VL  - 781
SN  - 0048-9697
CY  - Amsterdam [u.a.]
PB  - Elsevier Science
M1  - FZJ-2021-04686
SP  - 146732
PY  - 2021
AB  - Recent findings on soil organic matter (SOM) revealed that soil microorganisms are not only crucial for SOMformationthrough plant litter degradation but soil microbial biomass (SMB) may also directly contribute to SOMand its composition. However, the role and interactions of litter quality, microbial turnover and composition ofSMB and SOM remain unclear. Hence, soil profiles (organic forest floor and mineral soil layers) at a recultivatedand afforested post-mining site were investigated for the influence of litter quality from different tree species(Fagus sylvatica, Pseudotsuga menziesii, Pinus nigra) and soil depth – representing different degrees of organicmatter (OM) turnover – on the molecular composition of chloroform fumigation extracted SMB-derived compoundsin comparison with easily extractable (non-fumigated) SOM-derived compounds. The SMB extractswere analyzed for microbial biomass carbon (MBC), nitrogen(MBN) and phosphorus (MBP). Themolecular compositionof SMB and SOMcompoundswere determined by electrospray ionization Fourier transformation ion cyclotronresonance mass spectrometry (ESI-FT-ICR-MS) complemented by the determination of ninemonosaccharides representing microbial or plant origin.Van Krevelen diagrams obtained from the ESI-FT-ICR mass spectra revealed the substantial contribution ofmicrobial-derived compounds to extractable SOMthat further increasedwith soil depth. Analysis of the easily extractablemonosaccharidesimplied that>99%were of microbial origin. Microbial sugars aswell asMBC,MBNandMBP explained best depth-related variations of extractable SMB compounds indicating that supply and availabilityof C-rich OM drive these parameters. Furthermore, the contribution of microbial sugar C to MBC increasedwith depth, suggesting that recycling of carbohydrates is an adaptation strategy of microorganisms in C-limited  environments. The supply  of  tree species-specific substratesresulted in different chemical composition of SMB with largest differences between deciduous and coniferous stands and vice versa, microorganisms contributed to SOM resulting in large similarity in the composition of SOM and SMB.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000655621000005
DO  - DOI:10.1016/j.scitotenv.2021.146732
UR  - https://juser.fz-juelich.de/record/902933
ER  -