Influence of red mud on soil microbial communities: Application and comprehensive evaluation of the Biolog EcoPlate approach as a tool in soil microbiological studies

Abstract

Red mud can be applied as soil ameliorant to acidic, sandy and micronutrient deficient soils. There are still knowledge gaps regarding the effects of red mud on the soil microbial community. The Biolog EcoPlate technique is a promising tool for community level physiological profiling. This study presents a detailed evaluation of Biolog EcoPlate data from two case studies. In experiment "A" red mud from Ajka (Hungary) was mixed into acidic sandy soil in soil microcosms at 5-50 w/w%. In experiement "B" red mud soil mixture was mixed into low quality subsoil in a field experiment at 5-50 w/w%. According to average well color development, substrate average well color development and substrate richness 5-20% red mud increased the microbial activity of the acidic sandy soil over the short term, but the effect did not last for 10 months. Shannon diversity index showed that red mud at up to 20% did not change microbial diversity over the short term, but the diversity decreased by the 10 th month. 30-50% red mud had deteriorating effect on the soil microflora. 5-20% red mud soil mixture in the low quality subsoil had a long lasting enhancing effect on the microbial community based on all Biolog EcoPlate parameters. However, 50% red mud soil mixture caused a decrease in diversity and substrate richness. With the Biolog EcoPlate we were able to monitor the changes of the microbial community in red mud affected soils and to assess the amount of red mud and red mud soil mixture applicable for soil treatment in these cases.

A Standardized Method for Estimating the Functional Diversity of Soil Bacterial Community by Biolog® EcoPlatesTM Assay—The Case Study of a Sustainable Olive Orchard

“…The common pattern of the graphs of Figure 2 likely depends on the fact that the calculation of AWCD, H' and E are all based on the values of c i , as previously explained. Comparing our results with those of other studies [10][11][12][13][14][15][16] using our protocol, we managed to obtain more stable growth curves for AWCD, particularly in the constant phase and relatively low values of SD (Figure 2A). Another important remark is that the inoculum could be relativized simply resuspending soil mass, in order to not to artificially homogenize differences that are intended to be detected among the different soil samples of the same experiment [17][18][19][20].…”

The Effect of Bauxite Residue on the Avoidance Behavior of Enchytraeus albidus (Enchytraeidae)

“…The "r" value in the tables represents the correlation coefficient. Correlation was considered very strong when r-value > |0.85| and strong when r-value > |0.60| [41]. The concentration-response curves were generated with Origin 6.0 to determine LC x (lethal concentration) values.…”

Comparing biotic drivers of litter breakdown across stream compartments

“…Prokaryota potential activity (as aerobic metabolic potential to utilize different carbon sources) was measured by incubating filtered water subsamples in Biolog EcoPlate Systems (Biolog Inc.). Following Feigl, Ujaczki, Vaszita, and Molnár (), changes in the coloration of tetrazolium violet redox dye were used to measure prokaryotic respiration, and prokaryotic metabolic diversity was calculated as Shannon–Wiener diversity value (H') based on substrate utilization (see also Methods S1).…”