Study on Spatial Distribution of OM, N, P in Surface Soil around Lake Chaohu

The concentration of total nitrogen (TN), total phosphorus (TP) and organic material (OM) at sixty grid division in Lake Chaohu basin around the lake was studied, in order to investigate their spatial distribution characteristics. The results showed that the average concentrations of TN, TP and OM were 1027 mg/kg, 483 mg/kg, 1.95%, and their concentrations ranged from 253 mg/kg to 2273 mg/kg, 223 mg/kg to 1173 mg/kg and 0.291% to 5.48%, respectively. The high concentration areas were located at the basins of Tuogao river and Zhao river while the low concentration areas were located at basins of Pai river, Nanfei river and Dianpu river. The concentrations of TN and OM were higher in East part than in West part. The spatial distribution of TN, TP and OM concentrations of the surface soil showed inconsistent with those of the water quality of the inflow rivers and the lake and the TN and TP of lake sediment studied.

Microbial community functional structure in response to micro-aerobic conditions in sulfate-reducing sulfur-producing bioreactor

Limited oxygen supply to anaerobic wastewater treatment systems had been demonstrated as an effective strategy to improve elemental sulfur （So） recovery, coupling sulfate reduction and sulfide oxidation. However, little is known about the impact of dissolved oxygen （DO） on the microbial functional structures in these systems. We used a high throughput tool （GeoChip） to evaluate the microbial community structures in a biological desulfurization reactor under micro-aerobic conditions （DO： 0.02-0.33 rag/L）. The results indicated that the microbial community functional compositions and structures were dramatically altered with elevated DO levels. The abundances of dsrA/B genes involved in sulfate reduction processes significantly decreased （p 〈 0.05, LSD test） at relatively high DO concentration （DO： 0.33 mg/L）. The abundances of sox and fccA/B genes involved in sulfur/sulfide oxidation processes significantly increased （p 〈 0.05, LSD test） in low DO concentration conditions （DO： 0.09 mg/L） and then gradually decreased with continuously elevated DO levels. Their abundances coincided with the change of sulfate removal efliciencies and elemental sulfur （S^0） conversion efficiencies in the bioreactor. In addition, the abundance of carbon degradation genes increased with the raising of DO levels, showing that the heterotrophic microorganisms （e.g., fermentative microorganisms） were thriving under micro-aerobic condition. This study provides new insights into the impacts of micro-aerobic conditions on the microbial functional structure of sulfate- reducing sulfur-producing bioreactors, and revealed the potential linkage between functional microbial communities and reactor performance.