Climate change and water security in the northern slope of the Tianshan Mountains

Water security is under threat worldwide from climate change. A warming climate would accelerate evaporationand cryosphere melting, leading to reduced water availability and unpredictable water supply. However, thewater crisis in the Northern Slope of Tianshan Mountains(NSTM) faces dual challenges because water demandsforfast-growing urban areas have put heavy pressure on water resources. The mountain-oasis-desert system featuresglacier-fed rivers that sustain intensive water use in the oasis and end in the desert as fragile terminal lakes.The complex balance between water conservation and economic development is subtle. This paper investigateschanges in hydroclimatic variables and water security-related issues on the NSTM. The spatiotemporal variationsin glaciers, climatic variables, rivers, lakes and reservoirs, groundwater, surface water, human water use, andstreamflow were analyzed for the past four decades. The results show that temperature in the NSTM exhibitedan apparent upward trend with a more significant warming rate in the higher altitude regions. Glacier massloss and shrinkage was strong. The average annual streamflow increased from 1980-1989 to 2006–2011 at mosthydrological stations. The monthly dynamics of surface water area showed notable variability at both inter-annual and seasonal scales, revealing the impacts of both natural and anthropogenic drivers on surface wateravailability in the region. The terrestrial water storage anomaly showed a decreasing trend, which might berelated to groundwater pumping for irrigation. Human water use for agriculture and industry grew with theincrease in cultivated land area and gross domestic product (GDP). The increased agricultural water use wasstrongly associated with the expansion of oases. It is unclear whether water availability would remain high underfuture climatic and hydrological uncertainties, posing challenges to water management. In the context of rapidurban growth and climate change, balancing water for humans and nature is vital in achieving the SustainableDevelopment Goals (SDGs) in NSTM. This study provides a baseline understanding of the interplay among water,climate change, and socio-economic development in NSTM. It would also shed light on wise water managementunder environmental changes for other rapidly developing mountain-oasis-desert systems worldwide.

Spatial-temporal analysis of wetland landscape pattern under the influence of artificial dykes in the Yellow River delta

The influence of anthropogenic activities,especially artificial dykes,on the coastal wetland landscape is now considered as a serious problem to the coastal ecosystem.It is important and necessary to analyze changes of coastal landscape pattern under the influence of artificial dykes for the protection and management of coastal wetland.Our study aimed to reveal the quantitative characteristics of the coastal wetland landscape and its spatial-temporal dynamics under the influence of artificial dykes in the Yellow River delta(YRD).It was analyzed by the methods of the statistical analysis of landscape structure,five selected landscape indices and the changes of spatial centroids of three typical wetland types,including reed marshes,tidal fiats and aquaculture-salt fields.The results showed that:(1)Reduction of wetland area,especially the degradation of natural wetlands,had been the principal problem since the dykes were constructed in the YRD.The dykes created conditions for the development of artificial wetlands.However,the new born artificial wetlands were still less than the vanished natural wetlands.(2)Compared with the open area,the building of artificial dykes significantly speeded up the changes of landscape patterns and the aggravation of the landscape fragmentation in the closed area.(3)The changes of area-weighted centroids of three typical wetland landscapes were greatly affected by dykes,and the movement of the centroid of the aquaculture-salt field was very sensitive to the dykes constructed in the corresponding period.

Stable Isotope Composition of Rainfall, Surface Water and Groundwater along the Yellow River

The intention of this work is to consider the stable isotopic compositions of oxygen and deuterium in rainfall, surface water and groundwater along the Yellow River in the North China Plain(NCP). This demonstrated that the δ~18O values in groundwater varied from –10.17 to –6.85‰, with mean value of –8.76‰, and that the δD ranged from –68.7 to –58.0‰, with mean value of –63.4‰, respectively. The δ~18O values in surface water varied from –8.36 to 1.32‰, with mean value of –6.8‰, and δD ranged from –64.4 to –35.1‰, with mean value of –57.6‰, respectively. Further, The range of Cl-values of groundwater varied from 5.9 to 340.5 mg/L and that values ranged from 30.1 to 81.9 mg/L in surface water samples and Na^+ value changed from 27.4 to 321 mg/L in groundwater, while that in surface water varied from 24.8 to 50.5 mg/L. Most of the points fall below the GMWL, but are close to the LMWL. Therefore the results indicated that the groundwaters along the Yellow River were influenced by rainfall in heavy events and surface water.

Soil respiration in typical plant communities in the wetland surrounding the high-salinity Ebinur Lake

Soil respiration in wetlands surrounding lakes is a vital component of the soil carbon cycle in arid regions. However, information remains limited on the soil respiration around highly saline lakes during the plant growing season. Here, we aimed to evaluate diurnal and seasonal variation in soil respiration to elucidate the controlling factors in the wetland of Ebinur Lake, Xinjiang Uygur Autonomous Region, western China. We used a soil carbon flux automatic analyzer （LI-840A） to measure soil respiration rates during the growing season （April to November） in two fields covered by reeds and tamarisk and one field with no vegetation （bare soil） from 2015 to 2016. The results showed a single peak in the diurnal pattern of soil respiration from 11：00 to 17：00 for plots covered in reeds, tamarisk, and bare soil, with minimum values being detected from 03：00 to 07：00. During the growing season, the soil respiration of reeds and tamarisk peaked during the thriving period （4.16 and 3.75 μmol.m-2.s-1, respectively）, while that of bare soil peaked during the intermediate growth period （0.74 pmol-m-2-s-1）. The soil respiration in all three plots was lowest during the wintering period （0.08, 0.09, and -0.87 μmol.m-2.s-1, respectively）. Air temperature and relative humidity significantly influenced soil respiration. A significant linear relationship was detected between soil respiration and soil temperature for reeds, tamarisk, and bare soil. The average Q10 of reeds and tamarisk were larger than that of bare soil. However, soil moisture content was not the main factor controlling soil respiration. Soil respiration was negatively correlated with soil pH and soil salinity in all three plot types. In contrast, soil respiration was positively correlated with organic carbon. Overall,CO2 emissions and greenhouse gases had a relatively weak effect on the wetlands surrounding the highly saline Ebinur Lake.

Preparation and characterization of a new orange-red phosphor Ba_(2)LaTaO_(6):Eu^(3+)with abnormal thermal quenching

Herein,double-perovskite Ba_(2)LaTaO_(6) Eu-doped orange-red phosphors were successfully synthesized using a high-temperature solid-phase method.The phosphor phase purity was investigated using X-ray diffraction and microscopic morphology analyses.Their luminescence properties were investigated using absorption,emission,excitation,and temperature-dependent spectra.The transition mechanism mainly involves a magnetic-dipole transition with an energy transfer mode featuring multipole-multipole interactions,and concentration quenching is achieved via dipole-dipole interactions.In addition,the intensity of the temperature-dependent spectrum increases abnormally between 298 and 373 K,with the luminous intensity at 373 K increasing to 110%of that observed at room temperature.This phenomenon can be attributed to lattice defects in Ba_(2)LaTaO_(6):Eu^(3+),and the phosphor luminous intensity at473 K remains at 80.62%of that at room temperature.In addition,white-light-emitting diode devices based on this novel Ba_(2)LaTaO_(6):0.35Eu^(3+)phosphor were fabricated to evaluate the potential applications of the as-prepared phosphor.

Responses of greenhouse gas fluxes to experimental warming in wheat season under conventional tillage and no-tillage fields

Understanding the effects of warming on greenhouse gas（GHG, such as N2O, CH4 and CO2 ）feedbacks to climate change represents the major environmental issue. However, little information is available on how warming effects on GHG fluxes in farmland of North China Plain（NCP）. An infrared warming simulation experiment was used to assess the responses of N2O, CH4 and CO2 to warming in wheat season of 2012–2014 from conventional tillage（CT） and no-tillage（NT） systems. The results showed that warming increased cumulative N2O emission by 7.7% in CT but decreased it by 9.7% in NT fields（p 〈 0.05）. Cumulative CH4 uptake and CO2 emission were increased by 28.7%–51.7% and 6.3%–15.9% in both two tillage systems,respectively（p 〈 0.05）. The stepwise regressions relationship between GHG fluxes and soil temperature and soil moisture indicated that the supply soil moisture due to irrigation and precipitation would enhance the positive warming effects on GHG fluxes in two wheat seasons.However, in 2013, the long-term drought stress due to infrared warming and less precipitation decreased N2O and CO2 emission in warmed treatments. In contrast, warming during this time increased CH4 emission from deep soil depth. Across two years wheat seasons, warming significantly decreased by 30.3% and 63.9% sustained-flux global warming potential（SGWP） of N2O and CH4 expressed as CO2 equivalent in CT and NT fields, respectively. However, increase in soil CO2 emission indicated that future warming projection might provide positive feedback between soil C release and global warming in NCP.

Effects of drip irrigation on components of water cycle in arid inland areas: A case study of Manas river basin in northwestern China

Compared to either drip irrigation or mulching with plastic film,the two methods together can reduce water requirements of crops grown in arid areas by more than 30%.Such a combination deployed on a large scale(1)reduced the loss of soil water by 31.8%compared to that from drip irrigation alone;(2)narrowed the range of annual evapotranspiration from 1582.4-1780.3 mm,which is average for the basin,to 222.2-294.8 mm;and(3)increased the overall humidity in the central plain of the basin.However,the surrounding regions in which drip irrigation is not combined with mulching are getting more arid;thus,as a result of the water-saving technology,both oases and the desertification of the river basin are increasing at the same time.The results of the study further the understanding of the effects of drip irrigation combined with mulching on water cycles in the basin of the Manas river and suggest ways to protect the ecology and the environment of the basin.