Journal
FEMS MICROBIOLOGY ECOLOGY
Volume 86, Issue 1, Pages 139-148Publisher
OXFORD UNIV PRESS
DOI: 10.1111/1574-6941.12182
Keywords
DOC size classes; C3-C4 vegetation change; soil microbial biomass; (13); C; LC-IRMS
Categories
Funding
- Max-Planck-Gesellschaft
- Deutsche Forschungsgemeinschaft (DFG)
- International Max Planck Research School for Global Biogeochemical Cycles (IMPRS-gBGC)
Ask authors/readers for more resources
Soil dissolved organic carbon (DOC) sources and its seasonal dynamics are poorly known. We aimed to determine the contribution of plant and soil organic matter (SOM) to size classes of DOC in a field experiment with C3 to C4 vegetation change on two soil types through different seasons. Stable isotope ratios of DOC size classes were measured using size exclusion chromatography (SEC) coupled online to liquid chromatography-isotope ratio mass spectrometry (LC-IRMS). SEC resolved DOC into three size classes: very high molecular weight/vHMW (>10kDa), high molecular weight/HMW (0.4-10kDa), and low molecular weight/LMW (<0.4kDa). HMW DOC was most abundant in all seasons, soil types, and depths. In contrast, vHMW DOC was only seen postsnowmelt in upper 20cm and was mainly (87 +/- 9%) plant-derived. Through all seasons, HMW and LMW DOC had less than 30% recent plant contribution. Similar size range and source of DOC size classes and soil chloroform fumigation extracts suggest microbial origin of DOC. Thus, microbial SOM recycling is an important process in DOC production. We suggest that DOC molecules get partitioned manifold between soil solution and the mineral matrix (chromatography), thereby getting constantly decomposed, altered, or produced anew by soil microorganisms (reactive transport).
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available