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Abstract Anaerobic treatment of palm oil mill effluent (POME) was studied using a 16-litre laboratory scale up-flow anaerobic sludge blanket reactor (UASB) run over a range of influent concentrations from 5.1 to 42.5 g Chemical Oxygen Demand (COD) per litre at a constant hydraulic retention time of four days. Methane production, volatile fatty acid conversion, net sludge growth and Chemical Oxygen Demand reduction were monitored. Over 96% Chemical Oxygen Demand was removed at loadings up to 10.6 g COD l −1 day −1 . At the highest influent concentration reactor instability was observed. Up to this point the results indicated that the UASB could treat POME more effectively than other systems reviewed.

Widespread tree mortality associated with drought has been observed on all forested continents and global change is expected to exacerbate vegetation vulnerability. Forest mortality has implications for future biosphere-atmosphere interactions of carbon, water and energy balance, and is poorly represented in dynamic vegetation models. Reducing uncertainty requires improved mortality projections founded on robust physiological processes. However, the proposed mechanisms of drought-induced mortality, including hydraulic failure and carbon starvation, are unresolved. A growing number of empirical studies have investigated these mechanisms, but data have not been consistently analysed across species and biomes using a standardized physiological framework. Here, we show that xylem hydraulic failure was ubiquitous across multiple tree taxa at drought-induced mortality. All species assessed had 60% or higher loss of xylem hydraulic conductivity, consistent with proposed theoretical and modelled survival thresholds. We found diverse responses in non-structural carbohydrate reserves at mortality, indicating that evidence supporting carbon starvation was not universal. Reduced non-structural carbohydrates were more common for gymnosperms than angiosperms, associated with xylem hydraulic vulnerability, and may have a role in reducing hydraulic function. Our finding that hydraulic failure at drought-induced mortality was persistent across species indicates that substantial improvement in vegetation modelling can be achieved using thresholds in hydraulic function.

Abstract Two different strains of microalgae, one raphidophyte and one dinoflagellate, were tested under different abiotic conditions with the goal of enhancing lipid production. Whereas aeration was crucial for biomass production, nitrogen deficiency and temperature were found to be the main abiotic parameters inducing the high-level cellular accumulation of neutral lipids. Net neutral lipid production and especially triacylglycerol (TAG) per cell were higher in microalgae (>200% in Alexandrium minutum, and 30% in Heterosigma akashiwo) under treatment conditions (25°C; 330 μM NaNO3) than under control conditions (20°C; 880 μM NaNO3). For both algal species, oil production (free fatty acids plus TAG fraction) was also higher under treatment conditions (57 mg L−1 in A. minutum and 323 mg L−1 in H. akashiwo). Despite the increased production and accumulation of lipids in microalgae, the different conditions did not significantly change the fatty acids profiles of the species analyzed. These profiles consisted of saturated fatty acids (SAFA) and polyunsaturated fatty acids (PUFA) in significant proportions. However, during the stationary phase, the concentrations per cell of some PUFAs, especially arachidonic acid (C20:4n6), were higher in treated than in control algae. These results suggest that the adjustment of abiotic parameters is a suitable and one of the cheapest alternatives to obtain sufficient quantities of microalgal biomass, with high oil content and minimal changes in the fatty acid profile of the strains under consideration.

AbstractGlobal impact models represent process-level understanding of how natural and human systems may be affected by climate change. Their projections are used in integrated assessments of climate change. Here we test, for the first time, systematically across many important systems, how well such impact models capture the impacts of extreme climate conditions. Using the 2003 European heat wave and drought as a historical analogue for comparable events in the future, we find that a majority of models underestimate the extremeness of impacts in important sectors such as agriculture, terrestrial ecosystems, and heat-related human mortality, while impacts on water resources and hydropower are overestimated in some river basins; and the spread across models is often large. This has important implications for economic assessments of climate change impacts that rely on these models. It also means that societal risks from future extreme events may be greater than previously thought.

Carbon capture and storage (CCS) has been proposed as a potential technology to mitigate climate change. However, there is currently a huge gap between the current global deployment of this technology and that which will be ultimately required. Whilst CO2 can be captured at any geographic location, storage of CO2 will be constrained by the geological storage potential in the area the CO2 is captured. The geological storage potential can be evaluated at a very high level according to the tectonic setting of the target area. To date, CCS deployment has been restricted to more favourable tectonic settings, such as extensional passive margin and post-rift basins and compressional foreland basins. However, to reach the adequate level of deployment, the potential for CCS of regions in different tectonic settings needs to be explored and assessed worldwide. Surprisingly, the potential of compressional basins for carbon storage has not been universally evaluated according to the global and regional carbon emission distribution. Here, we present an integrated source-to-sink analysis tool that combines comprehensive, open-access information on basin distribution, hydrocarbon resources and CO2 emissions based on geographical information systems (GIS). Compressional settings host some of the most significant hydrocarbon-bearing basins and 36% of inland CO2 emissions but, to date, large-scale CCS facilities in compressional basins are concentrated in North America and the Middle East only. Our source-to-sink tool allows identifying five high-priority regions for prospective CCS development in compressional basins: North America, north-western South America, south-eastern Europe, the western Middle East and western China. We present a study of the characteristics of these areas in terms of CO2 emissions and CO2 storage potential. Additionally, we conduct a detailed case-study analysis of the Sichuan Basin (China), one of the compressional basins with the greatest CO2 storage potential. Our results indicate that compressional basins will have to play a critical role in the future of CCS if this technology is to be implemented worldwide. This research was performed within the framework of DGICYT Spanish Projects CGL2015-66335-C2-1-R and PGC2018-093903-B-C22, Grup Consolidat de Recerca “Geologia Sedimentària” (2017-SGR-824), and was also funded by the China Scholarship Council (CSC) (201806450043). JA received funding by EIT Raw Materials – SIT4ME Project (17024) and is now funded by MICINN (Juan de la Cierva fellowship - IJC2018-036074-I). EGR acknowledges funding by the AGAUR (Agència de Gestió d’Ajuts Universitaris i de Recerca) of the Generalitat de Catalunya (“Beatriu de Pinós” fellowship 2017SGR-824) and the Spanish Ministry of Science, Innovation and Universities (“Ramón y Cajal” fellowship RYC2018-026335-I). GJ is funded by the University of Strathclyde Faculty of Engineering. Peer reviewed