Revegetation of mined areas influences the physiological profile of bacterial communities and improves the biochemical functions of soil

Abstract

Mining activities have expanded worldwide to meet industrial demands and technological development. However, these activities have a negative impact on the environment that must be addressed. Thus, this study aimed to monitor the effects of the revegetation process on microbial proxies in an iron mine-degraded landscape using the biomass, activity, and metabolic capacity of the soil microbial community. We analysed an area that was recently mined and nonrevegetated (NR), areas that were mined and were under active revegetation (for 2 yrs and 3 yrs) and an unmined area covered with native vegetation (RA) in the mining province of Corumbá, Brazil. The results showed that there was an average gain of 44.6% and 48.15% in microbial biomass carbon in the 2 yr and 3 yr revegetated areas, respectively, compared to the NR area. We observed that after 3 yrs of revegetation, microbial biomass nitrogen increased by 86% compared to that in the nonrevegetated area. The enzymatic activity of phosphatase, fluorescence diacetate hydrolysis (FDA), and urease also increased as a function of revegetation time compared to the NR area. Phosphatase increased by 90% in the 3 yr revegetated area, FDA increased by 53% in the 2 yr revegetated area and 68% in the 3 yr revegetated area, and urease increased by 52% and 66% in the 2 yr and 3 yr revegetated areas, respectively, when compared to the NR area. The metabolic capacity of microorganism communities to degrade carbon sources returned rapidly, indicating an improvement in soil functioning in short time periods. Soil microbial proxies showed a high sensitivity to soil alterations in response to revegetation activities, highlighting their role as potential indicators in the rehabilitation process of mining-degraded landscapes.