scholarly journals Geographic Patterns of Bacterioplankton among Lakes of the Middle and Lower Reaches of the Yangtze River Basin, China

2020 ◽  
Vol 86 (6) ◽  
Author(s):  
Chengrong Bai ◽  
Jian Cai ◽  
Lei Zhou ◽  
Xingyu Jiang ◽  
Yang Hu ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Yangtze River ◽  
Yangtze River Basin ◽  
Assembly Process ◽  
Wet Season ◽  
Rare Taxa ◽  
Biogeographic Patterns ◽  
Geographic Patterns ◽  
Lower Yangtze ◽  
Rare Bacteria

ABSTRACT The revolution of molecular techniques has revealed that the composition of natural bacterial communities normally includes a few abundant taxa and many rare taxa. Unraveling the mechanisms underlying the spatial assembly process of both abundant and rare bacterial taxa has become a central goal in microbial ecology. Here, we used high-throughput sequencing to explore geographic patterns and the relative importance of ecological processes in the assembly of abundant and rare bacterial subcommunities from 25 lakes across the middle and lower reaches of Yangtze River basin (MLYB), located in Southeast China, where most of the lakes are interconnected by river networks. We found similar biogeographic patterns of abundant and rare subcommunities which could significantly distinguish the community compositions of the two lake groups that were far from each other but which could not distinguish the community compositions of the nearby lakes. Both abundant and rare bacteria followed a strong distance-decay relationship. These findings suggest that the interconnectivity between lakes homogenizes the bacterial communities in local areas, and the abundant and rare taxa therein may be affected by the same ecological process. In addition, based on the measured environmental variables, the deterministic processes explain a small fraction of variation within both abundant and rare subcommunities, while both neutral and null models revealed a high stochasticity ratio for the spatial distribution patterns of both abundant and rare taxa. These findings indicate that the stochastic processes exhibited a greater influence on both abundant and rare bacterial subcommunity assemblies among interconnected lakes. IMPORTANCE The middle and lower Yangtze Plain is a typical floodplain in which many lakes connect with each other, especially in the wet season. More importantly, with the frequent change of regional water level in the wet season, there is a mutual hydrodynamic exchange among these lakes. The microbial biogeography among these interconnected lakes is still poorly understood. This study aims to unravel the mechanisms underlying the assembly process of abundant and rare bacteria among the interconnected lakes in the middle and lower Yangtze Plain. Our findings will provide a deeper understanding of the biogeographic patterns of rare and abundant bacterial taxa and their determined processes among interconnected aquatic habitats.

Integrated biogeography and assembly process of planktonic and sedimentary bacterial communities in the Yangtze River

2020 ◽  
Author(s):  
Tang Liu ◽  
Jiawen Wang ◽  
Shufeng Liu ◽  
Qian Chen ◽  
Chunmiao Zheng ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Yangtze River ◽  
Selection Process ◽  
Anthropogenic Impacts ◽  
Spatiotemporal Pattern ◽  
Assembly Process ◽  
The Yangtze River ◽  
Species Sorting ◽  
Biogeographic Patterns ◽  
Water And Sediment

<p>Bacterial communities are essential to the biogeochemical cycle in riverine ecosystems. However, the integrated biogeography and assembly process of planktonic and sedimentary bacterial communities in large rivers is still poorly understood. Here, the study provided the spatiotemporal pattern of bacterial communities in the Yangtze River of 4300 km continuum, which is the largest river in Asia. We found that the taxa in sediments are the main contributors to the bacterial diversity of the river ecosystem since sediments sub-group took 98.8% of the total 38, 904 Operational Taxonomic Units (OTUs) observed in 280 samples. Seasonal differences in bacterial communities were statistically significant in water, whereas bacterial communities in both water and sediment were geographically clustered according to five types of landforms: mountain, foothill, basin, foothill-mountain, and plain. Interestingly, the presence of two huge dams resulted in a drastic fall of bacterial taxa in sediment immediately downstream due to severe riverbed scouring. The integrity of the biogeography was satisfactorily interpreted by the combination of neutral and species sorting perspectives in meta-community theory for bacterial communities in flowing water and sediment. Although deterministic process had dominant influence on assembly processes in water and sediment communities, homogeneous selection was the main contributor in water, while combination of homogeneous selection and variable selection contributed selection process in sediment. In addition, homogenizing dispersal played more important role in community assembly process in sediment than water. Our study fills a gap in understanding of biogeography and assembly process of bacterial communities in one of the world’s largest river and highlights the importance of both planktonic and sedimentary communities to the integrity of bacterial biogeographic patterns in a river subject to varying natural and anthropogenic impacts.</p>

scholarly journals Geographic Patterns of Bacterioplankton among Lakes of the Middle and Lower Reaches of the Yangtze River Basin, China

2019 ◽  
Author(s):  
Chengrong Bai ◽  
Jian Cai ◽  
Lei Zhou ◽  
Xingyu Jiang ◽  
Yang Hu ◽  
...  
Keyword(s):  
Microbial Community ◽  
Stochastic Processes ◽  
Aquatic Ecosystems ◽  
Yangtze River ◽  
Yangtze River Basin ◽  
Relative Importance ◽  
Ecological Processes ◽  
Microbial Biogeography ◽  
Geographic Patterns ◽  
Rare Bacteria

AbstractIn aquatic ecosystems, microbial biogeography research is critical for unveiling the mechanisms of microbial community succession. However, little is known about the microbial biogeography among interconnected lakes. To address this deficit, we used high-throughput sequencing to explore geographic patterns and the relative importance of ecological processes that shape these patterns in abundant and rare bacterial subcommunities from 25 lakes across the middle and lower reaches of Yangtze River basin (MLYB, located in southeast China), where most of the lakes are interconnected by river networks. We found that there were significant differences in both abundant and rare bacterial subcommunities between the two lake groups that were far from each other, while were no difference among the nearby lakes in each group. Both abundant and rare bacteria followed a strong distance-decay relationship, especially for rare bacteria. These findings suggest that although the interconnectivity between lakes breaks the geographical isolation of bacteria, the dispersal capability of bacterial taxa was still limited by geographic distance. We also found that although deterministic processes and stochastic processes together drive the bacterial subcommunities assembly, the stochastic processes (based on adjusted R2 in redundancy analysis) exhibited a greater influence on bacterial subcommunities. Our results implied that bacterial dispersal among interconnected lakes was more stochastically.ImportanceUnraveling the relative importance of ecological processes regulating microbial community structure is a central goal in microbial ecology. In aquatic ecosystems, microbial communities often occur in spatially structured habitats, where connectivity directly affects dispersal and metacommunity processes. Recent theoretical work suggests that directional dispersal among connected habitats leads to higher variability in local diversity and among-community composition. However, the study of microbial biogeography among natural interconnected habitats is still lacking. The findings of this study revealed interesting phenomena of microbial biogeography among natural interconnected habitats, suggested that the high interconnectivity reduced the spatial heterogeneity of bacteria, and caused the dispersal of bacteria to be more stochastically. This study has provided a deeper understanding of the biogeographic patterns of rare and abundant bacterial taxa and their determined processes among interconnected aquatic habitats.

scholarly journals Analysis of long-term terrestrial water storage variations in the Yangtze River basin

2013 ◽  
Vol 17 (5) ◽  
pp. 1985-2000 ◽  
Author(s):  
Y. Huang ◽  
M. S. Salama ◽  
M. S. Krol ◽  
R. van der Velde ◽  
A. Y. Hoekstra ◽  
...  
Keyword(s):  
River Basin ◽  
Yangtze River ◽  
Yangtze River Basin ◽  
Water Storage ◽  
The Yangtze River ◽  
Terrestrial Water Storage ◽  
Terrestrial Water ◽  
The Yangtze River Basin ◽  
Lower Yangtze ◽  
Gauging Station

Abstract. In this study, we analyze 32 yr of terrestrial water storage (TWS) data obtained from the Interim Reanalysis Data (ERA-Interim) and Noah model from the Global Land Data Assimilation System (GLDAS-Noah) for the period 1979 to 2010. The accuracy of these datasets is validated using 26 yr (1979–2004) of runoff data from the Yichang gauging station and comparing them with 32 yr of independent precipitation data obtained from the Global Precipitation Climatology Centre Full Data Reanalysis Version 6 (GPCC) and NOAA's PRECipitation REConstruction over Land (PREC/L). Spatial and temporal analysis of the TWS data shows that TWS in the Yangtze River basin has decreased significantly since the year 1998. The driest period in the basin occurred between 2005 and 2010, and particularly in the middle and lower Yangtze reaches. The TWS figures changed abruptly to persistently high negative anomalies in the middle and lower Yangtze reaches in 2004. The year 2006 is identified as major inflection point, at which the system starts exhibiting a persistent decrease in TWS. Comparing these TWS trends with independent precipitation datasets shows that the recent decrease in TWS can be attributed mainly to a decrease in the amount of precipitation. Our findings are based on observations and modeling datasets and confirm previous results based on gauging station datasets.

Lead pollution recorded in sediments of three lakes located at the middle and lower Yangtze River basin, China

2009 ◽  
Vol 208 (1-2) ◽  
pp. 145-150 ◽  
Author(s):  
Shuchun Yao ◽  
Bin Xue ◽  
Weilan Xia ◽  
Yuxing Zhu ◽  
Shijie Li
Keyword(s):  
River Basin ◽  
Yangtze River ◽  
Yangtze River Basin ◽  
Lead Pollution ◽  
Lower Yangtze

scholarly journals Analysis of long-term terrestrial water storage variations in Yangtze River basin

2012 ◽  
Vol 9 (10) ◽  
pp. 11487-11520 ◽  
Author(s):  
Y. Huang ◽  
M. S. Salama ◽  
M. S. Krol ◽  
R. van der Velde ◽  
A. Y. Hoekstra ◽  
...  
Keyword(s):  
River Basin ◽  
Yangtze River ◽  
Yangtze River Basin ◽  
Precipitation Amount ◽  
Temporal Analysis ◽  
Reanalysis Data ◽  
Full Data ◽  
Global Precipitation Climatology Centre ◽  
Lower Yangtze ◽  
Gauging Station

Abstract. In this study, we analyze 32 yr of TWS data obtained from Interim Reanalysis Data (ERA-Interim) and Noah model from Global Land Data Assimilation System (GLDAS-Noah) for the period between 1979 and 2010. The accuracy of these datasets is validated against 26 yr (1979–2004) of runoff dataset from Yichang gauging station and compared to 32 yr of independent precipitation data obtained from Global Precipitation Climatology Centre Full Data Reanalysis Version 6 (GPCC) and NOAA's PRECipitation REConstruction over Land (PREC/L). Spatial and temporal analysis of the TWS data shows that TWS in the Yangtze River basin is decreasing significantly since the year 1998. The driest period of the basin is noted from 2005 to 2010, especially in the middle and lower Yangtze reaches. The TWS changed abruptly into persistently high negative anomalies in the middle and lower Yangtze reaches in 2004. From both basin and annual perspectives, 2006 is detected as the major inflection point at which the system exhibits a persistent decrease in TWS. Comparing these TWS trends to independent precipitation datasets shows that the recent decrease in TWS can mainly be attributed to a decrease in precipitation amount. Our finding is based on observation and modeling data sets and confirms previous results based on gauging station datasets.

scholarly journals Quantification of Evaporative Sources of Precipitation and Its Changes in the Southeastern Tibetan Plateau and Middle Yangtze River Basin

Atmosphere ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 428 ◽  
Author(s):  
Yu Xu ◽  
Yanhong Gao
Keyword(s):  
Tibetan Plateau ◽  
River Basin ◽  
Yangtze River ◽  
Yangtze River Basin ◽  
Local Source ◽  
Wet Season ◽  
Southeastern Tibetan Plateau ◽  
Precipitation Recycling ◽  
The Indian Ocean ◽  
The Difference

The Southeastern Tibetan Plateau (SETP) and the Middle Yangtze River Basin (MYRB) show a large difference in their levels of precipitation, despite the fact that they are located within the same latitude band. The annual precipitation in the MYRB is much higher than in the SETP. Precipitation has decreased in the past three decades in both regions. To clarify the difference in precipitation and its changes between these two regions in recent decades, a quasi-isentropic backward trajectory (QIBT) model is used to track the evaporative source with the ERA-Interim reanalysis as the baseline. The wet seasons (from April to September) over the period of 1982–2011 were analyzed. Evaporative sources were divided into an oceanic portion and a terrestrial portion, in which local recycling was included. Our conclusions are as follows. A terrestrial evaporative source, including a neighboring terrestrial land source and local source, dominates both regions, although the summer monsoon regulates precipitation in the wet season. The local precipitation recycling ratio is 35% in the SETP and 29% in the MYRB. The oceanic evaporative source in the MYRB is five times larger than that in the SETP. The decrease in the oceanic evaporative source in the Indian Ocean is responsible for the decrease in precipitation in the SETP. In the MYRB, decreases in neighboring terrestrial sources dominate the precipitation decline. Regardless of the decreases in the remote oceanic or neighboring terrestrial evaporative sources, the local recycling ratio increased in both regions.

scholarly journals Changes in Forest Net Primary Productivity in the Yangtze River Basin and Its Relationship with Climate Change and Human Activities

2019 ◽  
Vol 11 (12) ◽  
pp. 1451
Author(s):  
Fengying Zhang ◽  
Zengxin Zhang ◽  
Rui Kong ◽  
Juan Chang ◽  
Jiaxi Tian ◽  
...  
Keyword(s):  
Climate Change ◽  
Spatial Distribution ◽  
River Basin ◽  
Primary Productivity ◽  
Yangtze River ◽  
Net Primary Productivity ◽  
Yangtze River Basin ◽  
The Yangtze River ◽  
The Yangtze River Basin ◽  
Lower Yangtze

Net Primary Productivity (NPP) is a basis of material and energy flows in terrestrial ecosystems, and it is also an important component in the research on carbon cycle and carbon budget. This paper evaluated the spatial distribution pattern and temporal change trends for forest NPP simulated by the LPJ (Lund-Potsdam-Jena) model and NDVI (normalized difference vegetation index) in the Yangtze River basin from 1982 to 2013. The results revealed that: (1) the spatial distribution of the forest NPP and NDVI in the Yangtze River basin has gradually decreased from the southeast coast to the northwest. The forest NPP and NDVI in the mid-lower Yangtze were higher than that of the upper Yangtze; (2) the forest NPP and NDVI in most areas of the Yangtze River basin were positively correlated with the temperature and precipitation. Moreover, the correlations among the temperature with the forest NPP and NDVI were stronger than that of correlations among precipitation with forest NPP and NDVI. Moreover, the extreme drought event in the year of 2004–2005 led the NPP to decrease in the middle and lower Yangtze River basin; (3) human activity such as major ecological projects would have a certain impact on the NPP and NDVI. The increase in forest areas from 2000 to 2010 was larger than that from 1990 to 2000. Moreover, the increasing rate for the NDVI was higher than that of NPP, especially after the year 2000, which indicates that the major ecological projects might have great impacts on the vegetation dynamics. Moreover, more attention should be paid on the joint impacts of human activity and climate change on terrestrial NPP and NDVI.

scholarly journals E-commerce promotes trade in invasive turtles in China

Oryx ◽  
2020 ◽  
pp. 1-4
Author(s):  
Sha Liu ◽  
Chris Newman ◽  
Christina D. Buesching ◽  
David W. Macdonald ◽  
Yu Zhang ◽  
...  
Keyword(s):  
River Basin ◽  
Yangtze River ◽  
Yangtze River Basin ◽  
Trachemys Scripta Elegans ◽  
Turtle Species ◽  
Online Sales ◽  
Freshwater Habitats ◽  
Lower Yangtze ◽  
Aquaculture Facilities ◽  
Wetland Habitats

Abstract Freshwater habitats in China are potentially suitable for invasive alien turtle species and, consequently, raising turtles in aquaculture facilities and the trade in turtles this supplies pose risks to habitats and native wetland communities when exotic turtles escape or are released deliberately. Online trade (e-commerce) is making an increasing contribution to turtle sales in China, seemingly driving demand and thus potentially exacerbating the risk of release. We document the scale and spatial pattern of online sales of non-native turtles over 90 days on China's Taobao.com e-commerce site. The majority of sales were in the ecologically sensitive middle and lower Yangtze river basin (82.35% of > 840,000 slider turtles Trachemys scripta elegans, and 68.26% of > 100,000 snapping turtles, Chelydridae spp.). These species are native to the Americas. Concurrently, over 2008–2018, we found 104 mentions of feral turtle issues listed on Baidu News where, among the 53 prefectures mentioned, issues with invasive turtle populations also focused predominantly in the middle and lower Yangtze river basin. Although circumstantial, this association suggests that the substantial online sale of alien turtles could be having detrimental effects in China's Yangtze river basin. It is important to safeguard these wetland habitats, which are of global importance, by improving policies for detecting and regulating invasive alien turtle issues and by warning consumers about the ecological hazard of their purchases.

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