How did the bacterial community respond to the level of urbanization along the Yangtze River?

2020 ◽  
Vol 22 (1) ◽  
pp. 161-172
Author(s):  
Yi Li ◽  
Luhuan Fan ◽  
Wenlong Zhang ◽  
Xiaoxiao Zhu ◽  
Mengting Lei ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Yangtze River ◽  
The Yangtze River ◽  
Urbanization Level ◽  
Bacteria Communities

The response of bacteria communities to the urbanization level.

scholarly journals Study on Urbanization Level, Urban Primacy and Industrial Water Utilization Efficiency in the Yangtze River Economic Belt

2019 ◽  
Vol 11 (23) ◽  
pp. 6571 ◽  
Author(s):  
Xuhui Ding ◽  
Zhu Fu ◽  
Hongwen Jia
Keyword(s):  
Yangtze River ◽  
Industrial Structure ◽  
Utilization Efficiency ◽  
Industrial Water ◽  
The Yangtze River ◽  
Urbanization Level ◽  
Water Utilization ◽  
Urban Primacy ◽  
Central Regions ◽  
Level Of Economic Development

Considering the undesirable output, this paper adopted the data envelopment analysis (DEA) model with the slack variable and super efficiency improvement, to measure industrial water utilization efficiency in the Yangtze River Economic Belt. The paper also creatively introduces urbanization level and urban primacy into driver factors’ estimation by stochastic and fixed Tobit models, exploring how urbanization characteristics affected the water utilization in regional industrial production. The results showed that industrial water efficiency has maintained an upward trend during the whole period, while most central and western provinces have shown a U-shaped trend of decreasing first and then rising. However, the industrial water utilization efficiency of central regions is the lowest, and the eastern regions are the highest, catching up with western regions. Utilization efficiency shows an overall convergence during the research period from 2005 to 2017. Regarding the factors’ estimation, both population urbanization and land urbanization negatively affected industrial water utilization efficiency, particularly blind expansion and disorderly development. The urban primacy meant the unbalance of urbanization, which would lead to urban diseases and pollution transfer, while the effects of urban primacy depended on the urbanization level. However, the utilization efficiency of industrial water did not become better automatically along with urbanization development; therefore, the scale and speed of urbanization should be scientifically formulated. The effects of the level of economic development, the advanced industrial structure, and the level of foreign investment are significantly negative.

scholarly journals The Spatial and Heterogeneity Impacts of Population Urbanization on Fine Particulate (PM2.5) in the Yangtze River Economic Belt, China

2019 ◽  
Vol 16 (6) ◽  
pp. 1058 ◽  
Author(s):  
Weiwei Xie ◽  
Hongbing Deng ◽  
Zhaohui Chong
Keyword(s):  
Air Pollution ◽  
Yangtze River ◽  
Spillover Effects ◽  
Empirical Literature ◽  
The Yangtze River ◽  
Urbanization Level ◽  
Fine Particulate ◽  
Heterogeneity Effects ◽  
Shape Curve ◽  
Population Urbanization

This paper addresses the effect of population urbanization on Fine Particulate (PM2.5) in the Yangtze River Economic Belt in China from 2006 to 2016 by employing PM2.5 remote sensing data and using the Stochastic Impacts by Regression on Population, Affluence and Technology (STIRPAT) model. The study contributes to the growing empirical literature by addressing heterogeneity, spillover, and dynamic effects in the dynamic spatial panel modeling process simultaneously. The empirical results show that population urbanization has a significant impact on PM2.5 with a positive spillover effect and a dynamic effect being detected and controlled. The heterogeneity effects of population urbanization on PM2.5 due to geographical positions show evidence of an obvious inverted U-shaped curve relationship in the upstream area and an increasing function curve in the midstream and downstream areas. The heterogeneity effects due to population urbanization levels show that an inverted N-shape curve relationship exists in low and medium urbanization level areas, while a U-shape curve relationship exists in high urbanization level areas. It is hoped that this study will inform the local governments about the heterogeneity of population urbanization and spillover effects of air pollution when addressing air pollution control.

scholarly journals Impact of Urbanization on the Environmental Regulation Efficiency in the Yangtze River Basin Based on the Empirical Analysis of Spatial Econometrics

2021 ◽  
Vol 18 (17) ◽  
pp. 9105
Author(s):  
Qian Zhang ◽  
Decai Tang ◽  
Brandon J. Bethel
Keyword(s):  
Economic Development ◽  
Yangtze River ◽  
Yangtze River Basin ◽  
Kuznets Curve ◽  
The Yangtze River ◽  
Urbanization Level ◽  
The Yangtze River Basin ◽  
Urbanization Rate ◽  
Impact Of Urbanization ◽  
Population Urbanization

Urbanization has been positioned as an important driving force for economic development. This article examines the impact of urbanization on environmental regulation efficiency (ERE) in the Yangtze River Basin (YRB). Based on a panel dataset of 97 cities in the YRB from 2005 to 2016, a spatial econometric model was used for analysis. Results show that the average ERE in the YRB is relatively low and manifests in the shape of a curved smile. The urbanization level of the permanent population is far lower than the average level of developed countries. However, the urbanization level is showing a steady growth trend. During this period, ERE in the Yangtze River middle, upper, and lower reaches was measured at 0.77, 0.58, and 0.52, respectively. The urbanization rate was measured at 0.59, 0.45, and 0.39, in the lower, middle, and upper reaches, respectively. When only considering population urbanization, the previously observed negative correlation between ERE and the Kuznets curve disappears. However, if the carrying capacity of economic activities is considered, the U-shaped relationship between urbanization rate and ERE returns. The environmental Kuznets curve is consequently verified. In addition, there is an inverted U-shaped nonlinear relationship between economic development and ERE. The results of this article show that there are unsustainable risks in the rapid pursuit of population urbanization. Only by improving the quality of urbanization and adapting the level of urbanization to the carrying capacity of resources and environment can we truly promote high-quality economic development. The article puts forward some suggestions to promote the green development of the economy.

scholarly journals The spatial-temporal differences in coupling relationship between urbanization and eco-environment-a case study of the urban agglomeration in the middle reaches of the Yangtze River

2018 ◽  
Vol 53 ◽  
pp. 03070
Author(s):  
Yue Chen ◽  
Yan Yu ◽  
Qianwen Han ◽  
Yan Tong ◽  
Yuanyuan Ke
Keyword(s):  
Spatial Pattern ◽  
Environmental Quality ◽  
Yangtze River ◽  
Evaluation System ◽  
Urban Agglomeration ◽  
Capital City ◽  
The Yangtze River ◽  
Coordinated Development ◽  
Urbanization Level ◽  
Development Level

Exploring the coupling coordinated relationship between urbanization and eco-environment of the urban agglomeration in the middle reaches of the Yangtze River (UAMRYR) from 2000 to 2015 can provide a theoretical basis for the overall planning and healthy development of the region. Therefore, in this article, we took 31 cities of the UAMRYR as the research area, and established an evaluation system to calculate the urbanization level and eco-environmental quality. Then, using entropy method and coupling measurement model, we analyzed the coupling coordination relationship between urbanization level and eco-environmental quality from spatial and temporal perspectives. Temporally, the coupling degree (CD) and coupling coordinated degree (CCD) continually rose during the 16 years. Spatially, the coordinated development level of urbanization level and eco-environmental quality had significant spatial differences. The CD presented the “northwest-southeast” spatial characteristics corresponding to high-low distribution. The CCD showed an inverted Y-shaped spatial pattern that gradually decreases outward from the provincial capital city. The coordinated development level of urbanization and eco-environment in the UAMRYR showed a central-periphery spatial pattern, and had an obvious spatial variation.

Key shaping factors of anammox bacterial geographical distribution and function in riverine ecosystems

2020 ◽  
Author(s):  
Sitong Liu ◽  
Liming Chen
Keyword(s):  
Environmental Factors ◽  
Bacterial Community ◽  
Yangtze River ◽  
Large Scale ◽  
Species Turnover ◽  
Alpha Diversity ◽  
Anammox Bacteria ◽  
The Yangtze River ◽  
Geographical Patterns ◽  
Anammox Activity

<p>The anaerobic ammonium oxidation (anammox) process converts ammonium to dinitrogen gas (N2) using nitrite as an electron acceptor under anaerobic conditions, which plays an important role in global nitrogen cycle. Anammox has been extensively investigated at different spatial scales. However, most previous studies have focused on the impacts of environmental factors on anammox bacterial community composition, whereas the influence of spatial factors, such as geographical distance, remains unclear. Here, we took sediment and water samples from two large-scale river in China: the Yangtze River. High-throughput biomolecule analysis was performed to explore the spatial patterns of anammox bacterial community and their response to environmental factors, spatial factors, community interchange and anammox bacterial traits. Additionally, 15N tracer analyses has been performed to estimated anammox activity and its contribution to N2 production (ra), and factors shaping its occurrence. Main conclusions are draw as follows: <br>(1) The Three Gorges Dam (TGD) induced sediment coarsening could enhance anammox role as an important N-sink and decrease anammox bacterial alpha diversity. Anammox is ubiquitous in sediment of the Yangtze River, with high bacterial abundance (1.0×105 to 2.90×108 copies g-1 dry sediment), and activity (0.003-6.67 nmol N g-1 h-1), accounting for 3.5-82.8% of total N2 production (ra). Our results showed that the ra at the post-dam site was steeper than that before the dam, whereas the alpha diversity of anammox bacteria showing an opposite trend. Further analysis showed that hydraulic erosion leads to sediment coarsening and loss of organic matter downstream of the dam, which ultimately leads to the enhancement of the ra and the decrease of anammox bacterial alpha diversity. TGD induced sediment coarsening would extend downstream nearly to the river mouth in the coming decades, which would inevitably enhance the importance of anammox in nitrogen loss and alter anammox bacterial community in the Yangtze River for a long time.<br>(2) A significant distance-decay relationship was observed for anammox bacterial community similarity in the Yangtze River, which was significantly influenced by geographical distance rather than local environmental factors. This implied that niche-independent dispersal limitation plays an important role in shaping anammox community assembly. Furthermore, the slope of the distance-decay curve was much higher than previously reported for whole bacteria, which indicating the species turnover rate of anammox bacteria (z-value = 0.35) was significantly higher than that of the whole bacteria (approximately 0.008-0.05). Anammox bacteria harbor stronger adsorption ability and film-forming ability than other bacteria. As such, anammox bacterial harbor lower dispersal potential, and ultimately exhibited a higher species turnover rate than whole bacteria.<br> This study investigated the geographical patterns and the driving mechanisms of anammox bacterial community in large-scale riverine ecosystems, and estimated the key shaping factors of anammox activity and its contribution to total N2 production. The results or conclusions of this study are of scientific significance for further revealing the community assembly and geographical patterns of anammox bacteria on a global scale, as well as the theoretical system of nitrogen cycle.</p>

Yiling Multi-span Cable-Stayed Bridge over the Yangtze River

2004 ◽  
Vol 88 (8) ◽  
pp. 59-64
Author(s):  
Changyu Shao ◽  
Qinger Deng
Keyword(s):  
Yangtze River ◽  
The Yangtze River ◽  
Cable Stayed Bridge
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