Tarbiat Modares University Journal of Agricultural Science and Technology 1680-7073 16 3 2014 05 01 Micromorphological and Biocalcification Effects of Sporosarcina pasteurii and Sporosarcina ureae in Sandy Soil Columns 681 693 14912 EN M. Sarmast Department of Soil Science, Faculty of agriculture, Shahid Bahonar University of Kerman, Kerman, Islamic Republic of Iran. M. H. Farpoor Department of Soil Science, Faculty of agriculture, Shahid Bahonar University of Kerman, Kerman, Islamic Republic of Iran. M. Sarcheshmehpoor Department of Soil Science, Faculty of agriculture, Shahid Bahonar University of Kerman, Kerman, Islamic Republic of Iran. M. K. Eghbal Department of Soil Science, Faculty of Agriculture, Tarbiat Modares University, Tehran, Islamic Republic of Iran. Journal Article Microbial calcium carbonate, by bridging sand particles, can play an important role in sand dune stability. A study was carried out on the cementation of sand grains and infilling of pore spaces by CaCO₃. Two bacterial species (<em>Sporosarcina pasteurii</em> and <em>Sporosarcina ureae</em>), three reactant concentrations (0.5, 1 and 1.5M), and six reaction times (12, 24, 48, 96, 192 and 288 hours) were tested in factorial experiment. Bacterial inocula and reactant solutions were added daily to sandy soil columns (6.5 cm height and inner diameter of 7.7 cm), while precipitation of CaCO₃being investigated within 0-1.5, 1.5-3, 3-4.5 and 4.5-6 cm intervals. Chemical and micromorphological analyses revealed that CaCO₃ formation, inorganic C sequestration, and depth of cementation were more profound for <em>S. pasteurii</em> as compared with <em>S. ureae</em>. Both microbial CaCO₃ precipitation and inorganic C sequestration increased with increase in reaction time from 12 to 288 hours. Increase in reactant concentration also caused an increase in CaCO₃ precipitation (by 12%). Micromorphological observations showed a high degree of calcite crystals’ bridging, coating on sand particles and as well infilling of pore spaces. <em>S. pasteurii</em> is thus recommended for being used in stabilization of sand dunes; due to its significant effects on CaCO₃ deposition and as well on sand grain cementation. https://jast.modares.ac.ir/article_14912_b7a09dca296f4517c1c7b5ca5e72c412.pdf