Effects of Silver Nanoparticles on Heterotrophic Bacterial Community Inhabiting the Anoxic Paddy Soil of Flooded Rice Microcosms

Although silver nanoparticles (AgNPs) have been applied more in our daily life. They are well known for their antimicrobial activities against a wide range of organisms but more concerns on the negative effects of AgNP products contaminated to the environment especially on most microorganism niches related to nutrient cycling in ecosystem. In the study, research was done to in understand the effects of AgNPs on heterotrophic bacterial populations in rice paddy soil. Both culturable N2-fixing bacteria and common heterotrophic bacteria could adapt themselves to AgNPs at low concentration (less than 50 ppm). However, more distinct reduction in N2-fixing bacteria against AgNPs were detected than heterotrophic bacterial niches at least 100 ppm AgNPs . These evidences indicated AgNPs at high concentration had significant adverse effects on the diverse microbial consortiums as well as rice seedlings.