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

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.

scholarly journals Spatiotemporal Pattern of Pine Wilt Disease in the Yangtze River Basin

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 731
Author(s):  
Zhuoqing Hao ◽  
Jixia Huang ◽  
Yantao Zhou ◽  
Guofei Fang
Keyword(s):  
River Basin ◽  
Yangtze River ◽  
Yangtze River Basin ◽  
Pine Wilt Disease ◽  
Wilt Disease ◽  
Spatiotemporal Pattern ◽  
Pinewood Nematode ◽  
The Yangtze River ◽  
Pine Wilt ◽  
The Yangtze River Basin

The Yangtze River Basin is among the river basins with the strongest strategic support and developmental power in China. As an invasive species, the pinewood nematode (PWN) Bursaphelenchus xylophilus has introduced a serious obstacle to the high-quality development of the economic and ecological synchronization of the Yangtze River Basin. This study analyses the occurrence and spread of pine wilt disease (PWD) with the aim of effectively managing and controlling the spread of PWD in the Yangtze River Basin. In this study, statistical data of PWD-affected areas in the Yangtze River Basin are used to analyse the occurrence and spread of PWD in the study area using spatiotemporal visualization analysis and spatiotemporal scanning statistics technology. From 2000 to 2018, PWD in the study area showed an “increasing-decreasing-increasing” trend, and PWD increased explosively in 2018. The spatial spread of PWD showed a “jumping propagation-multi-point outbreak-point to surface spread” pattern, moving west along the river. Important clusters were concentrated in the Jiangsu-Zhejiang area from 2000 to 2015, forming a cluster including Jiangsu and Zhejiang. Then, from 2015–2018, important clusters were concentrated in Chongqing. According to the spatiotemporal scanning results, PWD showed high aggregation in the four regions of Zhejiang, Chongqing, Hubei, and Jiangxi from 2000 to 2018. In the future, management systems for the prevention and treatment of PWD, including ecological restoration programs, will require more attention.

Bacterial communities along a 4500-meter elevation gradient in the sediment of the Yangtze River: what are the driving factors?

2020 ◽  
Vol 177 ◽  
pp. 109-130
Author(s):  
Wenlong Zhang ◽  
Haolan Wang ◽  
Yi Li ◽  
Xiaoxiao Zhu ◽  
Lihua Niu ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Yangtze River ◽  
Elevation Gradient ◽  
Driving Factors ◽  
The Yangtze River

Research on Characteristics of New Water and Sediment of Yichang Station after Impoundment of the Three Gorges

2013 ◽  
Vol 779-780 ◽  
pp. 1613-1618 ◽  
Author(s):  
Yan Hua Yang ◽  
Xiao Qiang Liu ◽  
Hong Qian Zhang
Keyword(s):  
Yangtze River ◽  
Three Gorges Reservoir ◽  
Test Method ◽  
Rank Test ◽  
Sediment Runoff ◽  
Three Gorges ◽  
The Yangtze River ◽  
The Three Gorges Reservoir ◽  
The Three Gorges ◽  
Water And Sediment

Reservoir regulation and reservoir sedimentation make conditions of flow and sediment under the dam change greatly after impoundment of the Three Gorges Project. This paper analyzes change trend and abrupt change situation of incoming water and sediment and studies characteristics of new flow and sediment of Yichang Station after impoundment of the Three Gorges with Mann-Kendall nonparametric rank test method. The result indicates that operation of the Three Gorges Reservoir has leveled runoff process and shortened dry season and extended median water period. After operation of the Three Gorges Reservoir, annual sediment runoff and monthly sediment runoff of some months changed suddenly and sediment runoff reduced sharply in Yichang Station. Sediment entering the middle and the lower reaches of the Yangtze River decreases substantially and it almost can be regarded as clean water discharge. Intorduction After operation of 175m normal water level of the Three Gorges Reservoir, total storage capacity of the reservoir is about 43 billion m3. Most of incoming sediment in the upstream is intercepted and deposited inside the reservoir and clean water and muddy water containing non-bed sand discharges. Change of water and sediment conditions destroys balance of downstream river and causes bed-rebuilding of downstream channels. And this results in a serious of long-term and long distance changes, such as on-way recovery of sand content, undercutting of bed scour, expansion of bank erosion and decline of water table, etc.[1-. Yichang Station controls a drainage area of 1005501km2 in upstream of the Yangtze River and is a major flood source for the middle and the lower reach of the Yangtze River. Thus, water regime information of Yichang Station is significant to flood control of the middle and the lower reach of the Yangtze River, regulation of the Three Gorges Reservoir, construction of water conservancy project all across the Yangtze River, industrial and agricultural production and shipping, etc. On account of this, this article analyzes data about coming water and sediment of Yichang Station to support characteristics of new flow and sediment of Yichang Station after impoundment of the Three Gorges with Mann-Kendall nonparametric rank test method.

Spatiotemporal pattern analysis of schistosomiasis based on village level in the transmission control stage in lake and marshland areas in China

Parasitology ◽  
2019 ◽  
Vol 147 (2) ◽  
pp. 199-212
Author(s):  
Yanyan Chen ◽  
Jianbing Liu ◽  
Ying Xiao ◽  
Chenhui Zhong ◽  
Fenghua Wei ◽  
...  
Keyword(s):  
Spatial Autocorrelation ◽  
Yangtze River ◽  
Hubei Province ◽  
Control Measures ◽  
Spatiotemporal Pattern ◽  
The Yangtze River ◽  
Jianghan Plain ◽  
Cluster Analyses ◽  
Village Level ◽  
The Village

AbstractHubei Province is one of the endemic regions with severe schistosomiasis in China. To eliminate schistosomiasis in lake and marshland regions, this study detected hotspots of schistosomiasis cases both spatially and spatiotemporally on the basis of spatial autocorrelation; clustering and outlier, purely spatial and spatiotemporal cluster analyses at the village level from 2013 to 2017 in Hubei Province. The number of cases confirmed positive by an immunodiagnostic test and etiological diagnosis and advanced schistosomiasis cases dramatically declined during the study period. Significant global spatial autocorrelation of schistosomiasis patients was found at the village level in the whole province in 5 years. Clustering and outlier analysis showed that most HH villages were mainly concentrated along the Yangtze River, especially in Jianghan Plain. Spatial and spatiotemporal cluster analyses showed that significant clusters of the schistosomiasis cases were detected at the village level. In general, space and spatiotemporal clustering of schistosomiasis cases at the village level demonstrated a downward trend from 2013 from 2017 in Hubei Province. High-risk regions included Jianghan Plain along the middle reach of Yangtze River and Yangxin County in the lower reaches of the Yangtze River in Hubei Province. To eliminate schistosomiasis, precise control and management of schistosomiasis cases should be strictly implemented. Moreover, comprehensive prevention and control measures should be continuously strengthened in these regions.

Biogeographic patterns of complete ammonia oxidizers (comammox) within the Yangtze River continuum

2021 ◽  
Author(s):  
Shufeng Liu ◽  
Haiying Wang ◽  
Jinren Ni
Keyword(s):  
Yangtze River ◽  
Ammonia Oxidation ◽  
Gene Clusters ◽  
Anthropogenic Factors ◽  
Ammonia Oxidizing Bacteria ◽  
The Yangtze River ◽  
Related Gene ◽  
Biogeographic Patterns ◽  
Environmental Selection ◽  
Phylogenetic Resolution

<p>The recent discovery of comammox <em>Nitrospira </em>performing complete ammonia oxidation to nitrate has fundamentally renewed the 120-year-held perspective of “two-step” nitrification. Rivers are known as the “Arteries” of the Earth, coupling the biogeochemical cycling of continents and oceans. Frequent human activities usually increase nitrogen load, and nitrifying microorganisms are crucial for the management of nitrogen load in rivers. The ecological roles of truncated nitrifiers, including canonical ammonia-oxidizing bacteria, ammonia-oxidizing archaea and nitrite-oxidizing bacteria in rivers have been fully understood, however, investigations of the newly discovered comammox <em>Nitrospira </em>are very scarce. To fill this gap, we used the metagenomic shotgun sequencing to provide the first biogeographic patterns of comammox <em>Nitrospira </em>in the Yangtze River over a 6030 km continuum.</p><p>First, ten novel comammox genomes (71~96% completeness) were reconstructed with the metagenome assemblies from fluvial water in the upper reach and surface sediments from the middle reach to the estuary. Gene arrangements in ammonia oxidation-related gene clusters of these novel genomes were more complex and diverse than those of the previously discovered ones. For instance, multi-copy <em>amoA </em>or <em>amoB </em>genes, peptidases, cupredoxin and <em>fkpA</em>-cytochrome <em>c</em>-<em>nirK </em>gene sets were first found within the ammonia oxidation-related gene clusters of comammox <em>Nitrospira</em>, which might confer them advantages in adapting to the relatively oligotrophic environments and stabilizing the ammonia-oxidation process in rivers. Taxonomic analysis demonstrated that all riverine comammox genomes (constituting four new species) belonged to clade A. Based on the phylogenies of their 37 “elite” conserved marker genes, we further separated all reported comammox clade A into five sublineages, named clade A-Ia, A-Ib, A-Ic and A-IIa, A-IIb. The reclassified sublineages were sufficiently divergent to be meaningful in expanding the taxonomic/functional diversity and improving the phylogenetic resolution.</p><p>Second, based on the improved phylogenetic resolution, we explored the biogeographic patterns of planktonic and benthic comammox <em>Nitrospira </em>subjected to natural and anthropogenic factors along the Yangtze River. Our study revealed the wide existence of comammox <em>Nitrospira </em>and their significant contributions to nitrifier abundances, constituting 30% and 46% of ammonia-oxidizing prokaryotes (AOPs) and displaying 30.4- and 17.9-fold greater abundances than canonical <em>Nitrospira </em>representatives in water and sediments, respectively. Comammox <em>Nitrospira </em>were found to contribute more to nitrifier abundances (34~87% of AOPs) in typical oligotrophic environments with a higher pH and lower temperature, particularly in the plateau (clade B), mountain and foothill (clade A-Ic) of the upper reach. Environmental selection determined the niche replacement of planktonic comammox <em>Nitrospira </em>by canonical ammonia-oxidizing bacteria and <em>Nitrospira </em>sublineages I/II from upstream to downstream, leading to a higher spatial turnover rate than observed for the benthic counterpart, while the dissimilarity of benthic comammox <em>Nitrospira </em>was moderately driven by geographic distance. A considerable decrease (83%) in benthic comammox <em>Nitrospira </em>abundance occurred immediately downstream of the Three Gorges Dam, which was consistent with a substantial decrease in the overall bacterial taxa in sediments.</p><p>Together, this study highlights the previously unrecognized dominance of comammox <em>Nitrospira</em> in major river systems and underlines the importance of revisiting the distributions of and controls on nitrification processes within global freshwater environments.</p>

Seasonal variation in water and sediment fluxes of the Yangtze River under precipitation change and human interference

2021 ◽  
Author(s):  
Yao Yue ◽  
Yuanfang Chai ◽  
Shitian Xu ◽  
Xiaofeng Zhang
Keyword(s):  
Yangtze River ◽  
Sediment Load ◽  
Water Discharge ◽  
Water Flux ◽  
Precipitation Change ◽  
The Yangtze River ◽  
Human Interference ◽  
Sediment Fluxes ◽  
Water And Sediment ◽  
Sediment Reduction

<p>Seasonal change of water and sediment fluxes is an important issue in flood/drought control and ecosystem protection. Based on trend analysis in dry and flood seasons during 1960–2014 at six major gauging stations on the Yangtze River, the largest river in China, significant homogenization of intra-year water discharge was found, while sharp decrease of sediment load in both seasons was tested. By reconstructing water and sediment series without the human interference, contributions of precipitation change, large dam constructions on the mainstream, and other human activities in each of the sub-basins of the Yangtze River were separated and quantified. It shows that precipitation change attributed for 9.5–23.6% to discharge homogenization in the middle and lower reaches of the Yangtze River, and increased sediment yield by 1.9–25.5% in both dry and flood seasons. Being the largest hydraulic project in the world, the Three Gorges Dam only explains 17.5–27.2% of the downstream homogenization in water flux, and 3.2–23.9% of sediment reduction in both seasons. Relatively small but massive human interference in the sub-basins was recognized as the primary factor, contributing over 60% to discharge homogenization and over 70% to seasonal sediment reduction, most notably in the Hanjiang sub-basin for water flux and in the Jianglingjiang sub-basin for sediment load.</p>

Water and Sediment Quality in Lakes along the Middle and Lower Reaches of the Yangtze River, China

2012 ◽  
Vol 26 (12) ◽  
pp. 3601-3618 ◽  
Author(s):  
Jinglu Wu ◽  
Haiao Zeng ◽  
Hong Yu ◽  
Long Ma ◽  
Longsheng Xu ◽  
...  
Keyword(s):  
Yangtze River ◽  
Sediment Quality ◽  
The Yangtze River ◽  
Water And Sediment ◽  
Water And Sediment Quality

Recent Evolution and Future Prediction of the Delta at the Yangtze River Mouth

2013 ◽  
Vol 353-356 ◽  
pp. 2699-2704 ◽  
Author(s):  
Ming Li ◽  
Yun Ping Yang ◽  
Yi Tian Li
Keyword(s):  
Mathematical Model ◽  
Yangtze River ◽  
River Mouth ◽  
Sediment Discharge ◽  
The Yangtze River ◽  
Discharge Data ◽  
One Dimensional ◽  
Water And Sediment ◽  
The Future ◽  
The One

In this study, an empirical curve describing the relation between erosion and deposition rate and water/sediment discharge was developed based on the recent evolution trend of the submerged delta at the Yangtze River Mouth, and the one-dimensional mathematical model for unsteady water-and sediment-transport was calibrated using the water and sediment discharge data after water impounding to predict the water and sediment discharge for the future 10 years and the future evolution of the submerged delta at the Yangtze River Mouth. The results showed that the 10 m and 20 m isobaths areas of the submerged delta changed with the water and sediment discharge from siltation to siltation slowing down to erosion. Siltation increased with large amount of rain received by the watershed during 1997-2000, while continuous retreat of erosion happened during 2000-2009. Using the one-dimensional mathematical model for river water and sediment calibrated and tested with data collected after impounding, the water and sediment discharges were calculated for Series 60 and 90, and its evolution in 2013-2022 was predicted for the delta. For Series 60, its 10 cm and 20 cm isobaths areas showed alternative scour and siltation, while the delta showed trends of erosion. For Series 90, its 10 m and 20 m isobaths showed substantial siltation in flood years. The water and sediment discharges since the Three Gorges Reservoirs was filled were lower than the calculated results for both Series 60 and 90. If the water and sediment discharges continue to decease, the delta will take an erosion trend.

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