Microbial community function and structure on coal mine discard under rehabilitation

Abstract

The rehabilitation of coal mine discard is problematic, especially since the lack of measures to evaluate the success of rehabilitation in terms of the self-sustainability of soil ecosystems established on these sites. In this study, the potential for using microbial community function and structure as such a measure was investigated using enzymatic assays (dehydrogenase, B-glucosidase, urease and acid and alkaline phosphatase) and signature lipid biomarkers (PLFAs). Samples from seven coal discard sites in South Africa currently under rehabilitation. were investigated and the relationship between soil properties, vegetation cover and microbial properties analysed using PCA and RDA ordination techniques. Although the discard sites had different rehabilitation ages (one to eight years). no statistically significant differences existed between these sites based on physical and chemical characteristics. Differentiation w~s possible based on enzymatic activities and PLFA profiles. Sites with relatively higher vegetation cover and organic carbon content had a positive association with enzymatic activities and microbial biomass. Organic carbon content correlated significantly with B-glucosidase (r = 0.80, P<0.05). urease (r = 0.96, P<0.05), acid phosphatase (r = 0.76, P<0.05), dehydrogenase (r = 0.69, P<0.10) and microbial biomass (r = 0.73. P<0.1 0). The characterisation of microbial community function and structure holds potential for evaluating rehabilitation progress on mine discard sites.

A Comparison of Microbial Community Function and Structure in Rehabilitated Asbestos and Coal Discard Sites

“…In recent years, the critical role of microbial communities as assessment criteria for the progress of rehabilitation on post-mining sites has been recognised (Claassens et al 2006(Claassens et al , 2008. Soil microbial communities not only play a crucial role in the establishment and maintenance of sustainable soil ecosystems, but they are timely and sensitive indicators of soil ecological stress and/or restoration processes (Bandick and Dick 1999;Badiane et al 2001;Ibekwe et al 2002).…”

PLFA Profiling of Coal Mine Spoil: An Integrated Approach for the Assessment of Ecological Restoration

“…Hydroxy PLFAs present in lipid moiety of lipopolysaccharides in cell wall are considered as potential biomarkers of gram-negative bacteria 15,38 . The changes in PLFAs is due to shift in microbial community composition 29,37 in chronosequence coal mine spoil over time.…”

“…Variation in PLFAs revealed the microbial community dynamics, which can be used as sensitive biomarker for periodic assessment of land degradation and progress of ecological restoration 4,28,29 . Undisturbed forest soil with defined microbial community structure in specific environmental conditions was used as reference that facilitate interpretation of the microbial community dynamics in mine spoil with increase in age of coal mine overburden.…”

The effect of canola (Brassica napus) as a biofumigant on soil microbial communities and plant vitality: a pot study

“…Soil samples for microbiological analyses (approximately 50 g each), were obtained aseptically at a depth of 0-15 cm from each pot (Claassens et al 2006). Sampling took place on the day of sunflower sowing (day 0), 21 d after sowing.…”