micromorphological and biocalcification effects of sporosarcina pasteurii and sporosarcina ureae in sandy soil columns

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 (sporosarcina pasteurii and sporosarcina ureae), 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 caco3 being 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 s. pasteurii as compared with s. ureae. 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. s. pasteurii 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.