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Abstract Recent publications on the successful mineralisation of carbon dioxide in basalts in Iceland and Washington State, USA, have shown that mineral storage can be a serious alternative to more mainstream geologic carbon storage efforts to lock away permanently carbon dioxide. In this study we look at the pore solution chemistry and mineralogy of basaltic glass and crystalline basalt under post-injection conditions, i.e. after rise of the pH via matrix dissolution and the first phase of carbonate formation. Experimental findings indicate that further precipitation of carbonates under more alkaline conditions is highly dependent on the availability of divalent cations. If the pore water is deficient in divalent cations, smectites and/or zeolites will dominate the secondary mineralogy of the pore space, depending on the basalt matrix. At low carbonate alkalinity no additional secondary carbonates are expected to form meaning the remaining pore space is lost to secondary silicates, irrespective of the basalt matrix. At high carbonate alkalinity, some of this limited storage volume may additionally be occupied by dawsonite −if the Na concentration in the percolating groundwater (brine) is high. Using synthetic seawater as a proxy for the groundwater composition and thus furnishing considerable amounts of divalent cations to the carbonated solution, results in massive precipitation of calcite, magnesite, and other Ca/Mg-carbonates under already moderate carbonate alkalinity. More efficient use of the basaltic storage volume can thus be attained by promoting formation of secondary carbonates compared to the inevitable formation of secondary silicate phases at higher pH. This can be done by ensuring that the pore water does not become depleted in divalent cations, even after carbonate formation. Using seawater as carbonating fluid or injection of CO2 into the basaltic oceanic crust, where saline fluids percolate, can reach this goal. However, such an approach needs sophisticated reactive transport modelling to adjust CO2 injection rates in order to avoid too rapid carbonate deposition and clogging of the pore space too close to the injection well.

China is confronted with an unprecedented water crisis regarding its quantity and quality. In this study, we quantified the dynamics of China?s embodied water use and chemical oxygen demand (COD) discharge from 2010 to 2015. The analysis was conducted with the latest available water use data across sectors in primary, secondary and tertiary industries and input?output models. The results showed that (1) China?s water crisis was alleviated under urbanisation. Urban consumption occupied the largest percentages (over 30%) of embodied water use and COD discharge, but embodied water intensities in urban consumption were far lower than those in rural consumption. (2) The ?new normal? phase witnessed the optimisation of China?s water use structures. Embodied water use in light-manufacturing and tertiary sectors increased while those in heavy-manufacturing sectors (except chemicals and transport equipment) dropped. (3) Transformation of China?s international market brought positive effects on its domestic water use. China?s water use (116?80 billion tonnes (Bts))(9) and COD discharge (3.95?2.22 million tonnes (Mts)) embodied in export tremendously decreased while its total export values (11?25 trillion CNY) soared. Furthermore, embodied water use and COD discharge in relatively low-end sectors, such as textile, started to transfer from international to domestic markets when a part of China?s production activities had been relocated to other developing countries.

Polycyclic aromatic hydrocarbons (PAHs) are airborne pollutants that are deposited on soils. As climate change is already altering temperature and solar radiation, the global warming is suggested to impact the environmental fate of PAHs. This study was aimed at evaluating the effect of climate change on the PAH photodegradation in soils. Samples of Mediterranean soils were subjected to different temperature and light radiation conditions in a climate chamber. Two climate scenarios were considered according to IPCC projections: 1) a base (B) scenario, being temperature and light intensity 20°C and 9.6W/m(2), respectively, and 2) a climate change (CC) scenario, working at 24°C and 24W/m(2), respectively. As expected, low molecular weight PAHs were rapidly volatilized when increasing both temperature and light intensity. In contrast, medium and high molecular weight PAHs presented different photodegradation rates in soils with different texture, which was likely related to the amount of photocatalysts contained in both soils. In turn, the hydrogen isotopic composition of some of the PAHs under study was also investigated to verify any degradation process. Hydrogen isotopes confirmed that benzo(a)pyrene is degraded in both B and CC scenarios, not only under light but also in the darkness, revealing unknown degradation processes occurring when light is lacking. Potential generation pathways of PAH photodegradation by-products were also suggested, being a higher number of metabolites formed in the CC scenario. Consequently, in a more or less near future, although humans might be less exposed to PAHs, they could be exposed to new metabolites of these pollutants, which might be even more toxic.

Abstract An assessment of the human impact on the global water cycle requires estimating the volume of water withdrawn for irrigated agriculture. A key parameter in this calculation is the irrigation efficiency, which corrects for the fraction of water lost between irrigation withdrawals and the crop due to management, distribution or conveyance losses. Here we show that the irrigation efficiency used in global irrigation models is flawed for it overlooks key ambiguities in partial efficiencies, irrigation technologies, the definition of ‘large-scale’ irrigated areas or managerial factors. Once accounted for, these uncertainties can make irrigation withdrawal estimates fluctuate by more than one order of magnitude at the country level. Such variability is larger and leads to more extreme values than that caused by the uncertainties related with climate change. Our results highlight the need to embrace deep uncertainties in irrigation efficiency to prevent the design of shortsighted policies at the river basin-water-agricultural interface.

In wetlands, a distinct zonation of plant species composition occurs along moisture gradients, due to differential flooding tolerance of the species involved. However, "flooding" comprises two important, distinct stressors (soil oxygen demand [SOD] and partial submergence) that affect plant survival and growth. To investigate how these two flooding stressors affect plant performance, we executed a factorial experiment (water depth x SOD) for six plant species of nutrient-rich and nutrient-poor conditions, occurring along a moisture gradient in Dutch dune slacks. Physiological, growth, and biomass responses to changed oxygen availability were quantified for all species. The responses were consistent with field zonation, but the two stressors affected species differently. Increased SOD increased root oxygen deprivation, as indicated by either raised porosity or increased alcohol dehydrogenase (ADH) activity in roots of flood-intolerant species (Calamagrostis epigejos and Carex arenaria). While SOD affected root functioning, partial submergence tended more to reduce photosynthesis (as shown both by gas exchange and 13C assimilation), leaf dark respiration, 13C partitioning from shoots to roots, and growth of these species. These processes were especially affected if the root oxygen supply was depleted by a combination of flooding and increased SOD. In contrast, the most flood-tolerant species (Juncus subnodulosus and Typha latifolia) were unaffected by any treatment and maintained high internal oxygen concentrations at the shoot : root junction and low root ADH activity in all treatments. For these species, the internal oxygen transport capacity was well in excess of what was needed to maintain aerobic metabolism across all treatments, although there was some evidence for effects of SOD on their nitrogen partitioning (as indicated by 865N values) and photosynthesis. Two species intermediate in flooding tolerance (Carex nigra and Schoenus nigricans) responded more idiosyncratically, with different parameters responding to different treatments. These results show that partial submergence and soil flooding are two very different stressors to which species respond in different ways, and that their effects on physiology, survival, and growth are interactive. Understanding species zonation with water regimes can be improved by a better appreciation of how these factors affect plant metabolism independently and interactively.

AbstractFloating photovoltaic system for reservoirs is a recent innovative technology that is highly advantageous in reducing evaporation while generating solar power. In addition, the integration of floating photovoltaic systems with the existing hydroelectric power plants will increase renewable power production. The present study aims to assess the electrical performance of floating photovoltaic systems in major reservoirs with existing hydroelectric power plants in India. The reservoirs with large water surface area were selected for the study, and a model floating photovoltaic system with a 5-MW capacity was designed for the selected reservoirs. The numerical analysis showed that installing floating photovoltaic systems will result in an annual energy yield of 160 GWh. Further, the systems also save 1.40 million cubic meters of water per day and also help in generating additional energy of 514.80 MWh/day from the saved water through its integration with hydroelectric power plants. A single-axis tracking mechanism to the floating photovoltaic systems will increase the annual energy generation by 11%. The detailed cost analysis and carbon emission analysis were also carried out. The results indicate that the tracking mechanisms increase the total installation cost of the systems. The annual carbon emission reduction from the floating photovoltaic systems accounts for about 3.30 million tons of CO2. The obtained results highlight the suitability of this innovative technology for installation in Indian reservoirs and its effectiveness in reducing evaporation and carbon emission. Graphic abstract

In this paper we argue for the need to apply a cognitive approach to understand deep dynamics and determinants of technological evolutions. After examining main contributions from innovation studies to the conceptualization of innovation and change in complex socio-technical environments, we highlight the contribution coming from the application of the cognitive approach to evolutionary studies on technologies and we introduce the concept of technological memory as an interpretative tool to understand those changes. We discuss our hypothesis with reference to several observations carried out in different local contexts – Mexico, India and Italy – in relation to technological change in the water sector. In those cases deliberate attempts to substitute traditional technologies with modern ones led to interesting trajectories of change ranging from the collapse of old technologies to the development of multifaceted hybridization patterns. Tema. Journal of Land Use, Mobility and Environment, 2014: INPUT 2014 - Smart City: planning for energy, transportation and sustainability of the urban system