scholarly journals Bacterial Communities Present Distinct Co-occurrence Networks in Sediment and Water of the Thermokarst Lakes in the Yellow River Source Area

2021 ◽  
Vol 12 ◽  
Author(s):  
Ze Ren ◽  
Cheng Zhang ◽  
Xia Li ◽  
Kang Ma ◽  
Zhe Zhang ◽  
...  
Keyword(s):  
Climate Change ◽  
Bacterial Communities ◽  
Environmental Variables ◽  
Yellow River ◽  
Source Area ◽  
Tibet Plateau ◽  
Future Climate Change ◽  
The Yellow River ◽  
Thermokarst Lakes ◽  
Yellow River Source

Thermokarst lakes are a ubiquitous and important landscape feature in cold regions and are changing tremendously due to the accelerated climate change. In thermokarst lakes, sediment and water are two distinct but highly interconnected habitats, harboring different bacterial communities in terms of taxonomic composition. However, the co-occurrence networks of these bacterial communities remain unclear. Here, we investigate the co-occurrence ecological networks of sediment and water bacterial communities for thermokarst lakes in the Yellow River Source Area on the Qinghai-Tibet Plateau. The results show that the bacterial communities construct distinct co-occurrence networks in sediment and water. The metacommunity network was parsed into four major modules formed by the operational taxonomic units (OTUs) enriched in sediment or water independently, and water-enriched OTUs exhibited much closer interconnections than sediment-enriched OTUs. When considering the sediment and water bacterial networks separately, different topological properties and modular patterns present: the sediment bacterial network was more clustered while the modules less responded to the environmental variables. On the contrary, the water bacterial network was more complex with the OTUs more interconnected and its modules more responded to the environmental variables. Moreover, the results of the structural equation model suggest that, by the influence of environmental variations on individual modules, the water bacterial communities would be more vulnerable under the fact of accelerating climate change. This study provides insights beyond a conventional taxonomic perspective, adding our knowledge of the potential mechanisms structuring bacterial community assembly and improving our prediction of the responses of this fast-changing ecosystem to future climate change.

scholarly journals Abundant and rare bacterial taxa structuring differently in sediment and water in thermokarst lakes in the Yellow River Source area, Qinghai-Tibet Plateau

2021 ◽  
Author(s):  
Ze Ren ◽  
Cheng Zhang ◽  
Xia Li ◽  
Kang Ma ◽  
Kexin Feng ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Yellow River ◽  
Source Area ◽  
Tibet Plateau ◽  
The Yellow River ◽  
Thermokarst Lakes ◽  
Β Diversity ◽  
Α Diversity ◽  
Yellow River Source ◽  
Qinghai Tibet Plateau

Thermokarst lakes are forming from permafrost thaw and severely affected by accelerating climate change. Sediment and water in these lakes are distinct habitats but closely connected. However, our understanding of the differences and linkages between sediment and water in thermokarst lakes remain largely unknow, especially from the perspective of bacterial community patterns and underlying mechanisms. In this study, we examined bacterial communities in sediment and water in thermokarst lakes in the Yellow River Source area, Qinghai-Tibet Plateau. Bacterial taxa were divided to abundant and rare according to their relative abundance, and the Sorensen dissimilarity (βsor) was partitioned into turnover (βturn) and nestedness (βnest). The results showed that the whole bacterial communities as well as the abundant and rare subcommunities differed substantially between sediment and water, in terms of taxonomical composition, α-diversity, and β-diversity. Sediment had significantly lower α-diversity indexes but higher β-diversity than water. Abundant taxa had significantly higher relative abundances but lower α-diversity and β-diversity than rare taxa. Moreover, bacterial communities are predominantly governed by strong turnover processes (βturn/βsor ratio of 0.925). Abundant subcommunities were significantly lower in βturn/βsor ratio compared to rare subcommunities. Bacterial communities in sediment had a significantly higher βturn/βsor ratio than in water. The results suggest that the bacterial communities of thermokarst lakes, especially rare subcommunities or particularly in sediment, might be strongly structured by environmental filtering and geographical isolation, leading to compositional distinct. By revealing bacterial communities in sediment and water, this integral study increased our current knowledge of thermokarst lakes, enhancing our understanding of the community assembly rules and ecosystem structures and processes of these rapid changing and vulnerable ecosystems.

scholarly journals Impact of Land Cover Types on Riverine CO2 Outgassing in the Yellow River Source Region

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2243
Author(s):  
Mingyang Tian ◽  
Xiankun Yang ◽  
Lishan Ran ◽  
Yuanrong Su ◽  
Lingyu Li ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Cover ◽  
Yellow River ◽  
Stream Water ◽  
Source Region ◽  
The Yellow River ◽  
Co2 Efflux ◽  
Land Cover Types ◽  
Yellow River Source ◽  
Alpine Rivers

Under the context of climate change, studying CO2 emissions in alpine rivers is important because of the large carbon storage in these terrestrial ecosystems. In this study, riverine partial pressure of CO2 (pCO2) and CO2 emission flux (FCO2) in the Yellow River source region (YRSR) under different landcover types, including glaciers, permafrost, peatlands, and grasslands, were systematically investigated in April, June, August, and October 2016. Relevant chemical and environmental parameters were analyzed to explore the primary controlling factors. The results showed that most of the rivers in the YRSR were net CO2 source, with the pCO2 ranging from 181 to 2441 μatm and the FCO2 ranging from −50 to 1574 mmol m−2 d−1. Both pCO2 and FCO2 showed strong spatial and temporal variations. The highest average FCO2 was observed in August, while the lowest average was observed in June. Spatially, the lowest FCO2 were observed in the permafrost regions while the highest FCO2 were observed in peatland. By integrating seasonal changes of the water surface area, total CO2 efflux was estimated to be 0.30 Tg C year−1. This indicates that the YRSR was a net carbon source for the atmosphere, which contradicts previous studies that conclude the YRSR as a carbon sink. More frequent measurements of CO2 fluxes, particularly through several diel cycles, are necessary to confirm this conclusion. Furthermore, our study suggested that the riverine dissolved organic carbon (DOC) in permafrost (5.0 ± 2.4 mg L−1) is possibly derived from old carbon released from permafrost melting, which is equivalent to that in peatland regions (5.1 ± 3.7 mg L−1). The degradation of DOC may have played an important role in supporting riverine CO2, especially in permafrost and glacier-covered regions. The percent coverage of corresponding land cover types is a good indicator for estimating riverine pCO2 in the YRSR. In view of the extensive distribution of alpine rivers in the world and their sensitivity to climate change, future studies on dynamics of stream water pCO2 and CO2 outgassing are strongly needed to better understand the global carbon cycle.

scholarly journals Research on valuation of water system in source region of the yellow river based on emergy theory

2018 ◽  
Vol 246 ◽  
pp. 01089
Author(s):  
Yongqiang Wang ◽  
Zhiming Liu ◽  
Zhe Yuan ◽  
Jijun Xu ◽  
Jin Chen
Keyword(s):  
Surface Water ◽  
Water Resources ◽  
Yellow River ◽  
Source Region ◽  
Source Area ◽  
The Yellow River ◽  
Energy Value ◽  
Surface Water Resources ◽  
Yellow River Source ◽  
Value Of Water

Taking the source region of the Yellow River as an example, this paper first introduces the theory of energy value and its basic steps. Then combined with the Yellow River source area, the variation characteristics of precipitation and surface water resources from 1961 to 2011 in the Yellow River source area were analyzed, and both of them showed a trend of decreasing year by year. On this basis, using the theory of energy value, combined with relevant parameters, taking 2011 year as an example, further analyses the chemical energy and solar energy of water resources in the Yellow River source area, and gives the value of surface water resources. The value of water resources per unit is 1.59 yuan/m3. For the Yellow River source area, the overall value of water resources for the whole basin in 2011 is 33.55 billion yuan. It can provide a reference for the analysis of the value of surface water resources in the Yellow River Basin.

Impact of Future Climate Change on Runoff in the Head Region of the Yellow River

2008 ◽  
Vol 13 (5) ◽  
pp. 347-354 ◽  
Author(s):  
Li Li ◽  
Zhen-Chun Hao ◽  
Jia-Hu Wang ◽  
Zhen-Hua Wang ◽  
Zhong-Bo Yu
Keyword(s):  
Climate Change ◽  
Yellow River ◽  
Future Climate ◽  
Future Climate Change ◽  
The Yellow River ◽  
Head Region

Application of Rn-222 isotope for the interaction between surface water and groundwater in the Source Area of the Yellow River

2016 ◽  
Vol 47 (6) ◽  
pp. 1253-1262 ◽  
Author(s):  
M. J. Zheng ◽  
C. W. Wan ◽  
M. D. Du ◽  
X. D. Zhou ◽  
P. Yi ◽  
...  
Keyword(s):  
Surface Water ◽  
Yellow River ◽  
Reference Value ◽  
Source Area ◽  
Tibet Plateau ◽  
The Yellow River ◽  
The North ◽  
Surface Water And Groundwater ◽  
Average Fraction ◽  
Qinghai Tibet Plateau

A pioneering rapid and direct measurement of dissolved 222Rn in the field has been used here to explore interaction between surface and groundwater in the source area of the Yellow River (SAYR). The results indicate average 222Rn activity of 2,371 Bq/m3 in surface water and 27,835 Bq/m3 in groundwater. The high 222Rn activity (up to 9,133 Bq/m3) found in the southeast part of the SAYR suggests possible influence of permafrost on the exchange between surface water and groundwater. The remarkable contrast among the different samples of a stream in the Shuangchagou basin, a typical basin in the SAYR, clearly indicates groundwater infiltration along the north tributary and occurrence of groundwater end-member in the south tributary. Considering no 222Rn decay and atmospheric evasion, the daily average fraction of groundwater input to the surface water through the end-member in a location (S1) is estimated at 19%. Despite the up to 40% uncertainty, this is the first estimate of a reference value for groundwater input in this basin and which can be improved in the future with more samples and measurements. 222Rn can be a rapid and easily measured tracer of surface water–groundwater interaction for future investigation in the Qinghai-Tibet Plateau.

Landform-related permafrost characteristics in the source area of the Yellow River, eastern Qinghai-Tibet Plateau

Geomorphology ◽  
2016 ◽  
Vol 269 ◽  
pp. 104-111 ◽  
Author(s):  
Jing Li ◽  
Yu Sheng ◽  
Jichun Wu ◽  
Ziliang Feng ◽  
Zuojun Ning ◽  
...  
Keyword(s):  
Yellow River ◽  
Source Area ◽  
Tibet Plateau ◽  
The Yellow River ◽  
Qinghai Tibet Plateau
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