Relief Of Water Stress Research Articles

Foliar Application of Amino Acids and Nutrients as a Tool to Mitigate Water Stress and Stabilize Sugarcane Yield and Bioenergy Generation

Extended periods of water stress negatively affect sugarcane crop production. The foliar application of supplements containing specific nutrients and/or organic molecules such as amino acids can improve sugarcane metabolism, stalk and sugar yields, and the quality of the extracted juice. The present study assessed the effectiveness of the foliar application of an abiotic stress protection complement (ASPC) composed of 18 amino acids and 5 macronutrients. The experiments were carried out in the field with two treatments and twelve replicates. The two treatments were no application of ASPC (control) and foliar application of ASPC. The foliar application of ASPC increased the activity of antioxidant enzymes. The Trolox-equivalent antioxidant capacity (DPPH) was higher in ASPC-treated plants than in control plants, reflecting higher antioxidant enzyme activity and lower malondialdehyde (MDA) levels. The level of H2O2 was 11.27 nM g−1 protein in plants treated with ASPC but 23.71 nM g−1 protein in control plants. Moreover, the application of ASPC increased stalk yield and sucrose accumulation, thus increasing the quality of the raw material. By positively stabilizing the cellular redox balance in sugarcane plants, ASPC application also increased energy generation. Therefore, applying ASPC is an effective strategy for relieving water stress while improving crop productivity.

Groundwater Vulnerability in a Megacity Under Climate and Economic Changes: A Coupled Sociohydrological Analysis

AbstractGroundwater depletion has become increasingly challenging, and many cities worldwide have adopted drastic policies to relieve water stress due to socioeconomic growth. Located on the declining aquifer of the North China Plain, Beijing, for example, has developed plans to limit the size of the city’s population. However, the effect of population displacement under uncertain macroeconomic and climate change remains ambiguous. We adopt a sociohydrological model, with explicit consideration of the dynamics of human‐water interactions, to explore the groundwater vulnerability of Beijing. We investigate how human response might shape the development trajectories of the groundwater‐population‐economy system under different macroscale economic and climate scenarios. Furthermore, we use a machine learning algorithm to identify the decisive factors to be considered for reducing groundwater vulnerability. Our results show that while rapid external economic development or larger annual average precipitation would enable recovery of the groundwater table in the short term, they may slacken human water shortage awareness and result in more acute groundwater depletion in the long run. Strengthening policymaker perceptions of groundwater depletion would prompt timely response policies for controlling population size. Improving the quantity and quality of labor force input to economic development would avoid downturns in the economy due to labor shortages. The outcomes of this study suggest that these strategies would effectively reduce groundwater vulnerability in the long run without causing severe socioeconomic recession. These findings highlight the importance of endogenizing human behavioral dynamics in sustainable urban water management.

Selecting suitable sites for groundwater recharge in Jordan using the spreading techniques via the integration of multi-criteria decision analysis and geographic information system tools

Over exploitation of groundwater resources in Jordan has resulted in the depletion and degradation of many groundwater aquifers. Most aquifers are heavily exploited and are expected to dry up by 2040. These pressing challenges require Jordan to find creative and sustainable solutions. Since the annual natural groundwater recharge rate is limited to 0.1–5%, managed aquifer recharge is a proposed solution for Jordan to enhance recharge. The spreading technique is one method used to deliberately recharge water into groundwater aquifers for subsequent recovery or environmental benefits. This study presents a tool based on a geographic information system-multi criteria analysis to identify the potential sites for groundwater recharge in Jordan using the spreading technique. Large sets of spatial data were used to develop a potential site suitability map for managed aquifer recharge spreading methods; the criteria were chosen based on technical, economic, and environmental considerations. The site assessment combined fourteen thematic maps to create suitability maps using the weighted linear combination approach, which were combined with constraint mapping using the Boolean logic. Constraint mapping showed that nearly 47% (7198 km2) of the study area did not meet the minimum criteria. The site assessment criteria on the remaining areas showed that about 4% (618.7 km2) of the study area has low suitability, 14% (2123 km2) has moderate suitability, 20% (3101 km2) is suitable, and 15% (2388 km2) is highly suitable. Managed aquifer recharge has a great potential in the relief of water stress in arid areas. Existing geospatial tools and the increasing availability of spatial data are a great asset to local authorities in water planners.

Progress and water stress of sustainable development in Chinese northern drylands

Water stress is a major challenge present in drylands and it generally leads to an uneven progress in social, economic, and natural systems. However, its impact on the achievement of sustainable development goals (SDGs) in drylands remains unclear. By establishing a comprehensive assessment system incorporating SDGs progress evenness, this study has assessed water stress and its impact on sustainable development in Inner Mongolia, a typical and representative area of Eurasian drylands. Our results suggest that although Inner Mongolia has experienced rapid progress towards its SDGs, disregarding the evenness of SDGs progress overestimates the current situation and ignores regional gaps. Many poorly performing SDGs have made little progress over the past few decades, thus intensifying uneven progress goals. Further analyses have examined how water resources are associated with these problems. Moreover, multiple SDGs related to human essential needs and environmental conservation, including SDG 1 (no poverty), SDG 2 (zero hunger), SDG 3 (good health and well-being), SDG 7 (affordable and clean energy), and SDG 12 (responsible consumption and production), were significantly positively correlated with ecological water consumption, whereas SDGs related to economic growth, such as SDG 8 (decent work and economic growth), were positively correlated with industrial water consumption. These findings suggest that a conflict in water allocation for the achievement of different SDGs accounts for the uneven progress across the SDGs and therefore this impedes the sustainable development of these drylands. Therefore, we argue that industrial upgrading, regional planning, and management policies should be integrated into a single unified framework from an SDGs perspective to relieve water stress, thus promoting sustainable development in drylands.

Optimization of Carbon Dioxide Foam Fracturing Technology for Shale Gas Reservoir

Major shale gas exploration and development fields are located in the Sichuan basin. It requires huge water sources for shale gas fracking, but the well sites are mostly in the hills, which limits the industrialization of shale gas development. CO2 foam fluids can meet the requirements of fracking fluids and relieve water stress. It analyzed the feasibility of CO2 foaming fracturing for shale gas formation fracturing, proposed a design philosophy for CO2 foaming fracturing, and optimized fracturing parameters such as foam mass, proppant concentration, friction, and discharge rate. The flowchart of CO2 foam fracturing was established in, where the fracture morphology and propagation behavior of CO2 foam fracturing were obtained from numerical simulations comparable to the hydraulic fracture generated by conventional hydraulic fracturing. The CO2 foaming fracturing technique can provide a discharge rate of 6.0 m3/min and fluid volume and captures the volume effect of the current stimulated reservoir, which needs to be improved. It can be considered an initial survey of CO2 foam fracturing available in the Sichuan Basin shale formation, which may provide new methods and clues for stimulation.

Water Resources Evaluation in Arid Areas Based on Agricultural Water Footprint—A Case Study on the Edge of the Taklimakan Desert

Water scarcity is an important factor limiting agricultural development in arid areas. Clarifying and evaluating the current situation of water resources in arid regions is helpful for decision-makers in the rational use of water resources. This study takes a typical arid region located at the edge of Taklamakan Desert-Hotan region as the study area. The water footprint (WF) of the Hotan region was calculated based on 20 years of data information from 2000–2019. An evaluation system was established using four aspects of the WF: structural indicators, efficiency indicators, ecological safety indicators, and sustainability indicators. The results show that the WF of the study area is mainly dominated by blue water consumption, with a proportion of 65.74%. The WF of crop production is larger than that of livestock production. The produced WF of grain crops is the highest of all products with a share of 44.21%. The increase in the local agricultural WF reached 53.18% from 2000 to 2019, but it was still lower than the amount of water available for agriculture. The evaluation results indicated that the region’s WF import dependency is lower than the global level, with an annual average self-sufficiency rate of 91.13% and an increase of 878.95% in the WF economic efficiency index. The agricultural WF produced in Hotan is exported in the form of trade, but the quantitative contribution is small and does little to relieve water stress in other regions. The agricultural water consumption was still within the range of local water resources that could be carried but only 6 years of sustainable water use, and the future development was not optimistic. With the ratio of produced WF to available water resources maintained at about 58%, the local available water resources should be above 43.21 × 108 m3 to initially ensure the sustainable use of water resources. There were 12 drought years in the study period, which are prone to droughts and high disaster levels. The drought-water scarcity systems behaved in three phases: 2000–2011 (uncoordinated level), 2012–2015 (transitional phase), and 2016–2019 (coordinated level). Water scarcity threatened by drought reduced. The occurrence of meteorological droughts was more related to natural factors while the changes in WF were mainly driven by socio-economic elements such as human activities.

Relieving water stress by optimizing crop structure is a practicable approach in arid transboundary rivers of Central Asia

With the challenges of arid transboundary river water management among Central Asian countries, it is important to evaluate the water stress and propose practicable climate adaptation strategies. This study used the Syr Darya Basin (SDB) in a Central Asia data scarce region as the study area and, conducted the first quantified analysis of the spatiotemporal characteristics of water supply and requirements at the basin and irrigation district scale; identified its driving mechanisms based on systematic monitoring data concerning reservoir regulation and complex crop structure from 2000 to 2018; and a climate change scenario combined with a crop restructuring scenario was applied to evaluate water conservation effects and propose a climate adaptation strategy from 2019 to 2030. The results showed that runoff increased by 7.45 billion m3 but the water withdrawal decreased by 3.42 billion m3 after reservoir regulation in the basin during 2000–2018. Due to the unified water allocation, it was challenging to conduct and usually exceeded the plan by 0.4–8.5 %. The total crop water requirement (TCWR) mainly derived from cotton (61.5 %), winter wheat (12.1 %) and rice (13.9 %) increased by 3.15 billion m3 (+30.7 %) and the influence of crop area (380 million m3/a) was greater than that of climate (130 million m3/a). The wind speed (27.5 %) and rice area (19.2 %) also significantly contributed to the TCWR variation. The contradiction between water supply and requirement resulted in water scarcity in the basin. From 2019–2030, the water conservation effect of winter wheat (+20 %) under the restructuring scenarios reached 28.7 mm, which helped relieve water stress under the scenario of a 0.51–0.91 °C increase. Thus, priority planting of a winter wheat rotation and low water consuming crops is a practicable approach for coping with water scarcity and adapting to climate change in arid transboundary rivers of Centra Asia.

A novel strategy to extend near-infrared light harvest of graphene for solar vapor generation and high-efficiency oil-water separation

Due to the feature of zero bandgap, graphene has presented a rapid and broadband photothermal responsibility. However, the near-infrared light absorption of graphene is relatively low, which is unfavourable for the full utilization of solar energy. Therefore, in our work, flower-like MoS2 nanostructure was used to promote the optical absorption of graphene. Further, combining with the porous skeleton of sugarcane residues and the simplified hydrophobic treatment method, a novel water treatment material (GNS@MoS2-SR) is successfully prepared. Recently, solar-assisted oily water treatment and solar steam generation were widely proposed to relieve the shortage of clean water. In the absorption test, it is confirmed that GNS@MoS2-SR can absorb 8.02–16.8 g/g oils from oil-water mixture and presents high stability during recycle. Moreover, the great hydrophobicity and photothermal conversion effect helps GNS@MoS2-SR to evaporate ∼1.778 kg/m2 water in 1 h, under one solar illumination (1 kW/m2). Besides, the optimized hydrophobicity of GNS@MoS2-SR effectively suppressed the salt precipitation and prevented the decline of spectrum absorption. The multifunctional water treatment material we designed integrates the respective advantages of graphene and MoS2, presents a significant potential in relieving water stress.

A policy support framework for the balanced development of economy-society-water in the Beijing-Tianjin-Hebei urban agglomeration

Balancing socioeconomic development with water resources among cities is critical for the sustainable development of urban agglomerations. Despite this urgent need to analyse balanced development, a recognized method to measure and improve the balanced degree in urban agglomerations impacted by water resource constraints is still lacking. This study proposes a framework to evaluate the balanced development degree and simulate the impacts of interactions and management policies of economy-society-water on balanced development in urban agglomerations. This paper establishes a balanced development degree index using the coupling coordinated degree (CCD) model; constructs a system dynamic (SD) model to simulate economy-society-water interactions; and designs future scenarios to evaluate the impacts of industry, population, water, and comprehensive regulation policies on balanced development. The integrated framework that couples the above three methods was validated in the Beijing-Tianjin-Hebei (BTH) region in China. The results showed that (a) industrial and population regulations slightly increase the level of balanced development by 0.0025 and 0.0024 in the BTH region but will increase water scarcity in Hebei; (b) improving water use efficiency is an effective way to relieve water stress; and (c) the balanced degree increases by 15% under comprehensive regulatory policies. Integrated water-economy-society management makes it possible to achieve co-development without increasing the water crisis in the BTH region. This study provides support for policy-makers and promotes sustainable development of the water-economy-society in urban agglomerations.

Treatment of Wastewater Effluent with Heavy Metal Pollution Using a Nano Ecological Recycled Concrete

Water pollution exacerbates water stress and poses a great threat to the ecosystem and human health. Construction and demolition waste (CDW) due to rapid urbanization also causes heavy environmental burdens. A major proportion of CDW can be effectively converted into recycled aggregates, which can be reused in many fields, including environment remediation. In this study, a nano ecological recycled concrete (nano-ERC) was produced with recycled aggregates and copper oxide nanoparticles (nCuO) to remove heavy metals (HMs) from a simulated wastewater effluent (SWE) for further treatment. Recycled aggregates were obtained from CDW, thereby simultaneously reducing the treatment cost of the SWE and the environmental burden of solid waste. The adsorption capacity of nano-ERC was presumed to be significantly enhanced by the addition of nCuO due to the unique large surface-to-volume ratio and other properties of nanoparticles. The SWE containing five common HMs, arsenic (As), chromium (Cr), cadmium (Cd), manganese (Mn) and lead (Pb), was filtered through a control ERC and nano-ERCs, and the concentrations of these HMs were determined with ICP-MS in the SWE and the filtrates. Results showed the nano-ERCs could significantly remove these HMs from the SWE compared to the control ERC, due to the enhanced adsorption capacity by nCuO. The relative weighted average removal percentage (RWAR%) was in the range of 53.05–71.83% for nano-ERCs and 39.27–61.65% for control ERC. Except for Cr, concentrations of these HMs in the treated wastewater effluent met the requirements for crop irrigation or scenic water supplementation; the Cr may be removed by multiple filtrations. In conclusion, nano-ERC can serve as a cost-effective approach for the further treatment of wastewater effluent and may be applied more widely in wastewater treatment to help relieve water stress.

Spatial equilibrium model-based optimization for inter-regional virtual water pattern within grain trade to relieve water stress

Abstract Realizing water usability and management sustainability represents one of the Sustainable Development Goals. Since grain cultivation consumes tremendous amounts of water, the inter-regional grain trade causes virtual water flow, increasing water stress in certain water-scarce regions. As the second-longest river in China, the Yellow River bears increasingly severe water stress. Considering water and food security, this study proposes a spatial equilibrium model (SEM) that combines partial equilibrium theory and transport models to maximize net social revenue and to balance grain supply and demand, thereby optimizing inter-regional grain trade to relieve water stress. According to different natural, technical and social conditions, we conceived five scenarios to predict regional water stress characterized with different water supplies, demographic structures, food demand compositions and water-saving technologies. Our simulation results suggest that the developed SEM can realize spatial equilibrium of food and water resources within the Basin, which is capable of resolving the problem of food demands in regions with varying extents (13%–55%), optimizing inter-regional grain trade and mitigating water stress. Finally, we recommend some constructive policies for different scenarios to relieve water stress.

An Environmentally Friendly Soil Amendment for Enhancing Soil Water Availability in Drought-Prone Soils

Applying soil amendments plays a critical role in relieving water stress in arid and semiarid areas. The natural clay mineral attapulgite (ATP) can be utilized to adjust the balance of water and soil environment. In this study, we investigated four different particle size distribution typical soils in the Loess Plateau: (1) lou soil (LS), (2) dark loessial soil (DS), (3) cultivated loess soil (CS), (4) sandy soil (SS). Five ATP application rates (0, 1%, 2%, 3%, and 4%) were selected to test the effect of ATP on the soil water retention curve, soil saturated hydraulic conductivity, and soil structure. The results showed that applied ATP significantly increased the soil clay content, and the relative change of SS with 3% ATP applied increased by 53.7%. The field water holding capacity of LS, DS, CS, and SS with 3% ATP applied increased by 8.9%, 9.6%, 18.2%, and 45.0%, respectively. Although applied ATP reduced the saturated hydraulic conductivity, the values of CS and SS were opposite when the amount of ATP applied was >3%. The relative change in the amount of 0.25–1 mm soil water-stable aggregates of SS was 155.9% when 3% ATP was applied. Applied ATP can enhance soil water retention and soil stability, which may improve limited water use efficiency and relieve soil desiccation in arid and semiarid areas or similar hydrogeological areas.

Effect of chloride ions on the corrosion behavior of carbon steel in an iron bacteria system.

Reclaimed water used as circulating cooling water can effectively relieve water stress, but the corrosion problem in it is very prominent. In particular, Cl− and iron bacteria (IB) are important influencing factors of corrosion behavior in a circulating water environment, and both of them often coexist in circulating water systems, so it is crucial to study their synergistic effects. This paper investigated the effect of Cl− on the corrosion behavior of carbon steel in the IB system by use of weight loss measurements, electro-chemistry and X-ray photoelectron spectroscopy (XPS). In the first 1–9 days of the experiment, the increase of Cl− concentration led to an increase of corrosion rate and a decrease of anode potential and charge transfer resistance at the interface. The corrosion rate of the 4ClIB condition reached 0.45 mm a−1 in the 1st day, which was 1.47 and 1.15 times that of 3ClIB and 1ClIB, and its anode potential was 22.6% and 33.8% lower than that of 3ClIB and 1ClIB. This indicates that a higher concentration of Cl− made the anodic reaction easier and the corrosion more severe. However, after 9 days, a decline in the corrosion rate was recorded at similarly high Cl− concentrations. On the 15th day, the corrosion rates for 3ClIB and 4ClIB were 7.0% and 15.6% lower compared to the 1ClIB condition. At this stage, the anode potential and film resistance had increased significantly, to become the dominant factors controlling the corrosion reaction. On the 15th day, the βa values of 1ClIB, 3ClIB and 4ClIB were 1.2, 1.5 and 1.7 times higher than those of the 1st day, and the highest Rb value of 1592.1 Ω cm2 was obtained for the 4ClIB condition, which was 1.9 times higher than that of Rct. In the early stage of corrosion, the surface of the carbon steel was enriched in Cl− due to their high concentration, and the Cl− could easily destroy the developing corrosion product film and promote the generation of Fe2+. At the same early stage, the growth of IB was enhanced, and the metabolism of IB was promoting local corrosion. However, in the later stage of corrosion, biofilms had an increasing effect on corrosion. A high concentration of Cl− accelerated biofilm growth and densified the corrosion product layer which subsequently hindered the anodic reaction and thus inhibited corrosion.

Carbon response of tundra ecosystems to advancing greenup and snowmelt in Alaska

The ongoing disproportionate increases in temperature and precipitation over the Arctic region may greatly alter the latitudinal gradients in greenup and snowmelt timings as well as associated carbon dynamics of tundra ecosystems. Here we use remotely-sensed and ground-based datasets and model results embedding snowmelt timing in phenology at seven tundra flux tower sites in Alaska during 2001–2018, showing that the carbon response to early greenup or delayed snowmelt varies greatly depending upon local climatic limits. Increases in net ecosystem productivity (NEP) due to early greenup were amplified at the higher latitudes where temperature and water strongly colimit vegetation growth, while NEP decreases due to delayed snowmelt were alleviated by a relief of water stress. Given the high likelihood of more frequent delayed snowmelt at higher latitudes, this study highlights the importance of understanding the role of snowmelt timing in vegetation growth and terrestrial carbon cycles across warming Arctic ecosystems.

Does the drought tolerance of guar [Cyamopsis tetragonoloba (L.) Taub.] extend belowground to root nodules?

AbstractIn cultivating guar [Cyamopsis tetragonoloba (L.) Taub], a drought‐tolerant legume, producers anticipate soil N credits through biological N fixation (BNF), but it has been speculated that root nodulation is poor under dry conditions and little is known about how nodules recover from drought stress. To provide better insight, two greenhouse studies were conducted to investigate static (25%, 50%, 75% and 100% ET replacement in two soils) and dynamic (50%, 75% and 100%, plus 50% and 75% relieved to 100% at 20 and 30 days after planting) water regimes on guar over 50 days. Water stress generally had the greatest negative impact on nodule weight, followed by aboveground biomass, reproductive nodes, height and then nodule number. Parameter responses were either linear or quadratic with ET replacement and response slopes differed between soils for nodule weight and biomass. The relatively minor effect on nodule number indicated the basic machinery for BNF (nodules) remained largely intact until water stress was extreme. This was likely a key factor that enabled strong and rapid recovery of nodule growth following relief of water stress. Biomass recovery was likewise robust, with production equal to the stress‐free control, regardless of the intensity and duration of the stress. These results show that nodule growth in guar is highly sensitive to water stress, but the plant is resilient in maintaining nodules under water stress and recovering nodule growth upon moisture restoration.

Living at the Water’s Edge: A World-Wide Econometric Panel Estimation of Arable Water Footprint Drivers

As part of the Sustainable Development Goal (SDG) for ensuring clean water and sanitation worldwide by 2030, SDG target 6.4 seeks to attain sustainable withdrawals of freshwater through efficiency gains with a view to relieving water stress in vulnerable populated areas. The water footprint (WF) is a key metric to measure this concept, although the dynamics of the drivers of the WF through space and time remain relatively under-researched, whilst in foresight studies, the WF is often subject to simplistic assumptions. Thus, constructing a panel dataset of 130 countries and 156 crops for the period 2002–2016, this paper empirically assesses the sign and magnitude of WF drivers of agricultural crop activities, employing a careful selection of demographic, economic and climatic drivers. The study uncovers evidence of significant deviations in WF drivers across regions segmented by relative wealth, relating specifically to the stage of economic development and the presence (absence) of economies of scale, whilst we confirm that geographical coordinates have a major bearing on the climatic WF driver. Moreover, examining the temporal dimension, there is compelling evidence supporting a structural break in the role that technical progress exerted on the WF prior to, and in the wake of, the 2008 financial crisis.

Water stress assessment integrated with virtual water trade and physical transfer water: A case study of Beijing, China

With the increase in population and economic development, urban water demand has increased significantly over the past decades, and physical transfer water (i.e., freshwater transported from water source regions to water intake regions through channels or pipelines) and virtual water (i.e., freshwater used in the production of goods and services along their supply chains, abbreviated as VW) have gradually become viable water sources for many cities to relieve water stress. This study used Beijing as the research object and systematically analyzed the impact of physical transfer water, VW, and local water on urban water stress from 2000 to 2016. The results show that VW inflow related to food trade has increased from 3.55 billion m3 in 2000 to 16.76 billion m3 in 2016, and that energy’s VW inflow increased from 52.76 million m3 to 137.47 million m3 over the same period. Before 2011, Beijing’s water demand was largely met by local water resources; however, after 2011, external water resources (including physical transfer water and VW) accounted for majority of the city’s water demand, and VW’s contribution increased from 47% in 2011 to 53% in 2016. Although Beijing has significantly reduced local water use in favor of external sources, its water stress index in 2016 remained considerable, far exceeding the upper limit of available water. This study also proposes some measures to ensure Beijing’s water security based on the sustainability of external water supply.

Water and energy circulation characteristics and their impacts on water stress at the provincial level in China

Water and energy circulate between provinces and sectors through products and services. The multi-scale input–output method can quantify the resources embodied in direct consumption, domestic trade and foreign trade and the resources in intermediate input and final consumption. In this study, this method is used to calculate the embodied water intensity and embodied energy intensity at the provincial level in China. The impacts of interprovincial water and energy transfers on provincial water stress were analyzed with reference to their water stress index. The results show that direct consumption is the main component of the embodied water intensity, with an average proportion of 52.21%. However, differences among provinces are significant, ranging from 14.82 to 80.11%. The embodied energy intensity is mainly reflected in domestic imports, with a national average of 61.01%. Domestic exports (3.69 × 1011 m3), urban household consumption (2.01 × 1011 m3), and gross fixed capital formation (1.49 × 1011 m3) share the largest proportion of final consumption, and they are also the main components in the final consumption of energy. Provincial water and energy transfers do not play major roles in relieving water stress in the net inflow areas but increase water stress in the net outflow areas. Provinces with high embodied water intensity and energy-induced water intensity tend to transfer more water to other provinces, while provinces with low intensity receive more supplies from other areas. Therefore, it is important to focus on improving the water use efficiency in provinces with active trade and high water and energy intensities, pay more attention to the demand side and avoid the continuous expansion of indirect consumption due to excessive restrictions on direct consumption.

The evolution of virtual water flows in China's electricity transmission network and its driving forces

Abstract Long-distance electricity transmissions could transfer water stress associated with electric power generation from the consumption side to the production side. In China, the rapidly growing scale of west-to-east electricity transmission is contributing to rising water stress in the arid northwestern regions. This study investigates the historical evolution and driving forces of virtual water network embodied in inter-provincial electricity transmissions in China during the past decade (2006–2016), measured by both volumetric and stress-weighted water consumption. Results show that electricity production hubs and load centers increasingly diverged in China. Driven by both growing electricity demand in eastern regions and an increasing share of imported electricity, stress-weighted virtual water export from the water-deficient northwestern provinces increased by 120% during the study period. Water efficiency improvements in thermoelectric power generation have offset 35% of the potential growth in total volumetric virtual water transfers, and more than 50% for stress-weighted virtual water transfers. However, the effect of water efficiency improvements has diminished since 2012. Considering China's ambitious plan to boost west-to-east electricity transmissions in the future, increasing the penetration of wind and solar photovoltaic power in electricity mix in northwestern regions should play a more significant role in relieving water stress in major electricity-exporting provinces.

Pseudomonas syringae Increases Water Availability in Leaf Microenvironments via Production of Hygroscopic Syringafactin.

The epiphytic bacterium Pseudomonas syringae strain B728a produces the biosurfactant syringafactin, which is hygroscopic. The water-absorbing potential of syringafactin is high. Syringafactin attracts 250% of its weight in water at high relative humidities but is less hygroscopic at lower relative humidities. This finding suggests that the benefit of syringafactin to the producing cells is strongly context dependent. The contribution of syringafactin to the water availability around cells on different matrices was assessed by examining the water stress exhibited by biosensor strains expressing gfp via the water-stress-activated proU promoter. Wild-type cells exhibited significantly less green fluorescent protein (GFP) fluorescence than a syringafactin-deficient strain on dry filters in atmospheres of high water saturation, as well as on leaf surfaces, indicating greater water availability. When infiltrated into the leaf apoplast, wild-type cells also subsequently exhibited less GFP fluorescence than the syringafactin-deficient strain. These results suggest that the apoplast is a dry but humid environment and that, just as on dry but humid leaf surfaces, syringafactin increases liquid water availability and reduces the water stress experienced by P. syringaeIMPORTANCE Many microorganisms, including the plant pathogen Pseudomonas syringae, produce amphiphilic compounds known as biosurfactants. While biosurfactants are known to disperse hydrophobic compounds and to reduce water tension, they have other properties that can benefit the cells that produce them. Leaf-colonizing bacteria experience frequent water stress, since liquid water is present only transiently on or in leaf sites that they colonize. The demonstration that syringafactin, a biosurfactant produced by P. syringae, is sufficiently hygroscopic to increase water availability to cells, thus relieving water stress, reveals that P. syringae can modify its local habitat both on leaf surfaces and in the leaf apoplast. Such habitat modification may be a common role for biosurfactants produced by other bacterial species that colonize habitats (such as soil) that are not always water saturated.