title: Soil Bacteria Population Dynamics Following Stimulation for Ureolytic Microbial-Induced CaCO3 Precipitation.
abstract: Microbial-induced CaCO3 precipitation (MICP) via urea-hydrolysis (ureolysis) is an emerging soil improvement technique for various civil engineering and environmental applications. In-situ application of MICP in soils is performed either by augmenting the site with ureolytic bacteria or by stimulating indigenous ureolytic bacteria. Both of these approaches may lead to changes in the indigenous bacterial population composition and to the accumulation of large quantities of ammonium. In this batch study, effective ureolysis was stimulated in coastal sand from a semiarid environment, with low initial ureolytic bacteria abundance. Two different carbon sources were used: yeast-extract and molasses. No ureolysis was observed in their absence. Ureolysis was achieved using both carbon sources, with a higher rate in the yeast-extract enrichment resulting from increased bacterial growth. The changes to the indigenous bacterial population following biostimulation of ureolysis were significant: Bacilli class abundancy increased from 5% in the native sand up to 99% in the yeast-extract treatment. The sand was also enriched with ammonium-chloride, where ammonia-oxidation was observed after 27 days, but was not reflected in the bacterial population composition. These results suggest that biostimulation of ureolytic bacteria can be applied even in a semiarid and nutrient-poor environment using a simple carbon source, that is, molasses. The significant changes to bacterial population composition following ureolysis stimulation could result in a decrease in trophic activity and diversity in the treated site, thus they require further attention.
authors.affiliation: The Department of Geological and Environmental Sciences, Ben-Gurion University of the Negev , Beer-Sheva 8410501, Israel.
authors.forename: Daniella
authors.initials: D
authors.lastname: Gat
authors.affiliation: The Department of Environmental Hydrology and Microbiology, The Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev , Sede-Boqer Campus 8499000, Israel.
authors.forename: Zeev
authors.initials: Z
authors.lastname: Ronen
authors.affiliation: The Department of Geological and Environmental Sciences, Ben-Gurion University of the Negev , Beer-Sheva 8410501, Israel.|The Department of Structural Engineering, Ben-Gurion University of the Negev , Beer-Sheva 8410501, Israel.
authors.forename: Michael
authors.initials: M
authors.lastname: Tsesarsky
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D003889:Desert Climate; D006868:Hydrolysis; D007557:Israel; D008965:Molasses; D012336:RNA, Ribosomal, 16S / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D012822:Silicon Dioxide; D012988:Soil Microbiology; D014508:Urea / Q000378:metabolism*; D015003:Yeasts / Q000737:chemistry
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012822:Silicon Dioxide; D014508:Urea