Carbon turnover and microbial activity in an artificial soil under imposed cyclic drainage and imbibition

• DOI: 10.1002/vzj2.20021
• Publication Date: 2020-04-02T03:34:54Z
• Authors: Geertje J. Pronk; Adrian Mellage; Tatjana Milojevic; Christina M. Smeaton; Katja Engel; Josh D. Neufeld; Fereidoun Rezanezhad; Philippe Van Capp...
• Keywords: Imbibition; Biogeochemical Cycle

Abstract Water table fluctuations generate temporally and spatially dynamic physicochemical conditions that drive biogeochemical hot spots moments in the vadose zone. However, their role cycling of soil C remains poorly known. Here, we present results from unvegetated column experiments filled with 45 cm artificial containing 10% humus, inoculated a natural microbial extract. In one series three replicate columns, five cycles, each consisting 4‐wk drainage followed by imbibition period, were imposed, whereas second series, water remained static. Depth‐resolved O 2 concentration profiles headspace CO effluxes markedly different between two regimes. fluctuating regime, periods yielded 2.5 times greater than periods. At end experiment, columns exhibited distinct zone organic (OC) depletion depth interval 8–20 was not observed under static regime. Although this showed elevated levels adenosine triphosphate (ATP), biomass actually lower at corresponding A vertically stratified community established all depended on oxygenation depth. The 16S ribosomal RNA (rRNA) gene analyses slightly higher diversity exposed to moisture fluctuations, but there no clear difference major taxa composition treatments. These thus suggest localized enhancement OC degradation induced driven more active, rather abundant or compositionally very different, community.