关键词: 生长率, 人工夜间灯光, 功能性状, 香樟, 城市生态系统

Abstract: Ionic strength and water saturation have significant impacts on transport and deposition of bacteria in porous medium. In this study, column breakthrough experiments with IVIS Spectrum System were performed to investigate the effects of ionic strength and water saturation on transport and retention of target bacteria Escherichia coli T7 under three levels of ionic strength (2, 50, 100 mM) and two levels of water saturation (85%, 100%). At same ionic strength, the migration of E. coli T7 under saturated condition was stronger than that under unsaturated condition.M_eff of saturated and unsaturated column was 34% and 8% at 100 mM, respectively. In line with above results, the onesite kinetic estimated parameterk_att of unsaturated column was 7.7 times higher than the corresponding values of saturated column at 100 mM. Results of DLVO and capillary force showed that decrease of E. coli T7 migration under unsaturated condition was caused by adsorption of airwater interface due to capillary force. In saturated column, increase of ionic strength promoted deposition of E. coli T7. With ionic strength increasing from 2 mM to 100 mM, M_res of saturated column increased from 47% to 58%, with decrease of electrostatic repulsion and increase of radius of E. coli T7 being the causes. Increase of ionic strength promoted deposition of E. coli T7 under unsaturated condition, which was more significant than that under saturated condition. With ionic strength increasing from 2 mM to 100 mM, M_res of unsaturated columns enhanced from 46% to 84%. Increase of M_res under unsaturated condition was 2.5 times higher than that under saturated condition. The main reasons were decreasing of electrostaticrepulsion and increasing of capillary force. Results of IVIS Spectrum System showed that deposition of E. coli T7 was more significant at inlet of saturated columns, and increasing ionic strength promoted retention. The retention profiles of saturated column were prone to be exponential gradually over time. The retention profiles were non-monotonic in unsaturated column. As ionic strength decreased, the position of max retention quantity moved to outlet of the columns.

Key words: urban ecosystem, functional trait, growth rate., Cinnamomum camphora, artificial nighttime light