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Wang C.,Changjiang Water Resource Protection Institution | Zhai W.,Yangtze Valley Water Environment Monitoring Center | Yin W.,Changjiang Water Resource Protection Institution | Shan B.,CAS Research Center for Eco Environmental Sciences
Environmental Science and Pollution Research | Year: 2015

Oxygen penetration is a key determinant of sediment nitrification rates. In this study, we analyzed the effect of oxygen penetration on the sediment nitrification rate based on sediment oxygen profiles. Six sediments were designed to produce different oxygen profiles by adding different amounts of silica gel to the collected river mud. The oxygen profiles in the sediment were detected using a voltammetric microelectrode. With increased mud content, the sediment oxygen penetration depth decreased from 8.3 to 2.6 mm, and the oxygen concentration in the overlying water and at the sediment-water interface also showed a decreasing trend. The measured nitrification rate displayed a quadratic pattern that changed with the increase in mud content. Based on the detected oxygen profiles, the nitrification rate at each depth was calculated and summed to obtain the bulk sediment nitrification rate. The bulk sediment nitrification rate showed a consistently changing pattern with the measured rate. Oxygen profiles used to calculate nitrification rates could be approximated by the penetration depth (δ). The resulting nitrification model based on δ could explain the limiting role of oxygen penetration in sediment nitrification. © 2015 Springer-Verlag Berlin Heidelberg Source

Tang W.J.,Hohai University | Tang W.J.,Yangtze River Scientific Research Institute | Ren L.,Yangtze River Scientific Research Institute | Xu H.,Yangtze Valley Water Environment Monitoring Center | And 3 more authors.
Advanced Materials Research | Year: 2014

The contradiction between water shortage and social needs has become an important factor restricting economic development. As freshwater, flood could be used as the natural resources to resolve the problem of water shortage, and also has some environmental benefits. Taking Danjiangkou reservoir as example, we adopt dynamic control method of limited water level to discuss the potential socioeconomic benefits of flood utilization. © (2014) Trans Tech Publicutions, Switzerland. Source

Fang D.,Wuhan University of Technology | Chen S.,Yangtze Valley Water Environment Monitoring Center | Jiang M.,Wuhan University of Technology | Li Q.,Wuhan University of Technology | And 3 more authors.
Materials Science in Semiconductor Processing | Year: 2014

Anodic titanium oxide TiO2 nanotube membranes with one, two and three layers have been prepared by the anodic oxidation method via adjusting applied bias during the oxidation process in glycol electrolytes containing 0.25 wt% or 0.50 wt% NH4F. The morphologies of the as-prepared samples were presented in detail using scanning and transmission electron microscopy. The results indicated that the glycol electrolyte containing 0.25 wt% NH 4F yielded smooth double-walled nanotubes, and their tubes remained open in multilayers; while the glycol electrolyte containing 0.50 wt% NH 4F yielded single-wall nanotubes with ripples, and most of the nanotubes have closed bottoms. In the case of nanotubes with closed bottoms, it was proposed that the newly grown nanotubes on the succeeding layer formed in the gap between the nanotubes of the previous layer. In order to keep track of the growth of the nanotubes, samples were anodized for different periods of time from 1 to 90 min to study their formation process. Growth mechanisms were proposed for different morphologies. © 2013 Published by Elsevier Ltd. All rights reserved. Source

Qu G.,Wuhan University | Qu G.,Changjiang River Scientific Research Institute | Xu H.,Yangtze Valley Water Environment Monitoring Center | Guo X.H.,Changjiang River Scientific Research Institute | Zhu Y.H.,Changjiang River Scientific Research Institute
Procedia Engineering | Year: 2012

Based on the measured data from 1957 to 2007 in Jingjiang river, this paper analyzed the water level change in Jingjiang river in low water and bank-full discharge, and then established the relationship between the value of water level change and river sediment scour-silt amount with the measured topographic data after the cut-off. The results show that the relations are well at Shashi and Xinchang stations while the correlation is not obvious at Jianli station. Finally, the paper analyzed the influencing factors of water level change in Jingjiang river in view of the water and sediment changes before and after the impoundment of Three Gorges reservoir and found that the recent water level change in Jingjiang river is mainly caused by the incoming sediment concentration change in the main stream of Changjiang river. © 2012 Published by Elsevier Ltd. Source

Hu M.,CAS Wuhan Institute of Hydrobiology | Hu M.,University of Chinese Academy of Sciences | Li Y.,CAS Wuhan Institute of Hydrobiology | Li Y.,University of Chinese Academy of Sciences | And 8 more authors.
Fresenius Environmental Bulletin | Year: 2012

The community composition and seasonal variation of bacterioplankton were investigated using 16S rRNA gene sequence analysis in high mount Lake Erhai, China. Restriction fragment length polymorphism (RFLP) analysis revealed remarkable seasonal fluctuations in bacterioplanktonic composition. A total of 1498 clones were obtained from 16 water samples, and most of clones belonged to the clusters α-Proteobacteria, β-Proteobacteria, γ- Proteobacteria, Actinobacteria, Bacteroidetes, Verrucomicrobia, and Cyanobacteria. Among these groups, α-Proteobacteria was the identified as most dominant group in spring and summer. However, the structure shifted toward a β-Proteobacterium-dominant community in autumn and winter. The clone libraries were found having the greatest diversity in winter, and some species only appeared in their specific seasons. The number of operational taxanomic uints (OTUs) predicted for the Lake Erhai ranged from 42.7 to 98.0, significantly lower than the samples from low-altitude lakes. The results of partial redundancy analysis (RDA) showed that environmental factors associated with nitrogen could play an important role in driving the conversion of two major groups in Lake Erhai. The present study indicated that the bacterioplankton communities of Erhai Lake were similar to other freshwater ecosystems as many sequences showed 93.8% - 100% homology with known sequences found in other freshwater ecosystems, but had many unique characteristics. And also part of communities predicted to be from marine ecosystems.These findings provided fundamental and specofic information on the structure of bacterioplankton and the microfood web in Lake Erhai. © PSP Volume 21 - No 1a.2012. Source

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