scholarly journals Relative Contributions of Land Use and Climate Change to Water Supply Variations over Yellow River Source Area in Tibetan Plateau during the Past Three Decades

PLoS ONE ◽  
2015 ◽  
Vol 10 (4) ◽  
pp. e0123793 ◽  
Author(s):  
Tao Pan ◽  
Shaohong Wu ◽  
Yujie Liu
2021 ◽  
Author(s):  
Yinglu Chen ◽  
Chun Chang Huang ◽  
Yuzhu Zhang ◽  
Yali Zhou ◽  
Xiaochun Zha ◽  
...  

2021 ◽  
Vol 12 ◽  
Author(s):  
Ze Ren ◽  
Cheng Zhang ◽  
Xia Li ◽  
Kang Ma ◽  
Zhe Zhang ◽  
...  

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.


2018 ◽  
Vol 11 (2) ◽  
pp. 367-379 ◽  
Author(s):  
Sho Momiyama ◽  
Masaki Sagehashi ◽  
Michihiro Akiba

Abstract Adverse effects of future climate change on water supply systems are of concern. High turbidity caused by abrupt flood, and drought caused by continuous dry days are the major risks. To assess such risks, a comprehensive method to simulate hydrology with high spatiotemporal resolution should be developed. In this study, a series of methods from parameter estimation to future simulation using the Soil and Water Assessment Tool (SWAT) was demonstrated for Sagami Dam reservoir, which is a typical water supply reservoir in Japan. A proposed parameter calibration method by optimizing percent bias followed by optimizing Nash–Sutcliffe efficiency gave good performance of model prediction of the daily average reservoir inflow in the past. Using this model, the changes in inflow under expected climate change were simulated. Three predicted daily climates by the Model for Interdisciplinary Research on Climate version 5 (MIROC5) under three representative concentration pathways, i.e., RCP 2.6, 4.5, and 8.5, in 2081–2100 were used for the simulation, whereas observed daily climate during 1981–2000 was used as the past reference. The risks were discussed by considering their seasonality, indicating increases in flood and drought in June and July, and in February and April, respectively.


Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2243
Author(s):  
Mingyang Tian ◽  
Xiankun Yang ◽  
Lishan Ran ◽  
Yuanrong Su ◽  
Lingyu Li ◽  
...  

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.


2018 ◽  
Vol 246 ◽  
pp. 01089
Author(s):  
Yongqiang Wang ◽  
Zhiming Liu ◽  
Zhe Yuan ◽  
Jijun Xu ◽  
Jin Chen

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.


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