[Seasonal Stratification and the Response of Water Quality of a Temperate Reservoir--Zhoucun Reservoir in North of China].

In order to reveal the seasonal stratification and the response of water quality of a temperate reservoir Zhoucun Reservoir in North of China. The physical, chemical and phytoplankton indexes were continuously monitored from July 2014 to June 2015. The results showed that the thermal stratification was monomictic, which lasted from April to October. The thermal stratification played an important role in the change of water environment. The hypoxia in the bottom water caused hy thermal stratification led to the release of nutrients and reductants from sediment. During the stratification period, the mean concentrations of total nitrogen, total phosphorus, manganese and sulfide were 1.18, 0.11, 0.47 and 0.48 mg · L⁻¹, respectively. The vertical distribution of phytoplankton was significantly influenced by water temperature stratification. During the thermal stratification period, phytoplankton abundance was higher and the average phytoplankton ahundance was 16.35 x 106 cells · L⁻¹ in the upper water of the reservoir, while remained at low levels at the bottom.

Nitrogen removal characteristics of enhanced in situ indigenous aerobic denitrification bacteria for micro-polluted reservoir source water.

Indigenous oligotrophic aerobic denitrifiers nitrogen removal characteristics, community metabolic activity and functional genes were analyzed in a micro-polluted reservoir. The results showed that the nitrate in the enhanced system decreased from 1.71±0.01 to 0.80±0.06mg/L, while the control system did little to remove and there was no nitrite accumulation. The total nitrogen (TN) removal rate of the enhanced system reached 38.33±1.50% and the TN removal rate of surface sediment in the enhanced system reached 23.85±2.52%. TN removal in the control system experienced an 85.48±2.37% increase. The densities of aerobic denitrifiers in the enhanced system ranged from 2.24×10(5) to 8.13×10(7)cfu/mL. The abundance of nirS and nirK genes in the enhanced system were higher than those of in the control system. These results suggest that the enhanced in situ indigenous aerobic denitrifiers have potential applications for the bioremediation of micro-polluted reservoir system.