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Summary Past climatic fluctuations have played a major role in shaping the current plant biodiversity. Although harbouring an exceptional biota, oceanic islands have received little attention in studies on species demographic history and past vegetation patterns. We investigated the impact of past climatic changes on the effective population size of a tree (Coffea mauritiana) that is endemic to Reunion Island, located in the south‐western Indian Ocean (SWIO). Demographic changes were inferred using summary statistics calculated from genomic data. Using ecological niche modelling and the current distribution of genetic diversity, the paleodistribution of the species was also assessed. A reduction in the effective population size of C. mauritiana during the last glaciation maximum was inferred. The distribution of the species was reduced on the western side of the island, due to low rainfall. It appeared that a major reduction in rainfall and a slight temperature decrease prevailed in the SWIO. Our findings indicated that analyses on the current patterns of intraspecific genetic variations can efficiently contribute to past climatic changes characterisation in remote islands. Identifying area with higher resilience in oceanic islands could provide guidance in forest management and conservation faced to the global climate change.

Bioplastics are alternatives of conventional petroleum-based plastics. Bioplastics are polymers processed from renewable sources and are biodegradable. This study aims at conducting an environmental impact assessment of the bioprocessing of agricultural wastes into bioplastics compared to petro-plastics using an LCA approach. Bioplastics were produced from potato peels in laboratory. In a biochemical reaction under heating, starch was extracted from peels and glycerin, vinegar and water were added with a range of different ratios, which resulted in producing different samples of bio-based plastics. Nevertheless, the environmental impact of the bioplastics production process was evaluated and compared to petro-plastics. A life cycle analysis of bioplastics produced in laboratory and petro-plastics was conducted. The results are presented in the form of global warming potential, and other environmental impacts including acidification potential, eutrophication potential, freshwater ecotoxicity potential, human toxicity potential, and ozone layer depletion of producing bioplastics are compared to petro-plastics. The results show that the greenhouse gases (GHG) emissions, through the different experiments to produce bioplastics, range between 0.354 and 0.623 kg CO2 eq. per kg bioplastic compared to 2.37 kg CO2 eq. per kg polypropylene as a petro-plastic. The results also showed that there are no significant potential effects for the bioplastics produced from potato peels on different environmental impacts in comparison with poly-β-hydroxybutyric acid and polypropylene. Thus, the bioplastics produced from agricultural wastes can be manufactured in industrial scale to reduce the dependence on petroleum-based plastics. This in turn will mitigate GHG emissions and reduce the negative environmental impacts on climate change.

Atmospheric concentrations of the greenhouse gas nitrous oxide (N(2)O) have increased significantly since pre-industrial times owing to anthropogenic perturbation of the global nitrogen cycle, with animal production being one of the main contributors. Grasslands cover about 20 per cent of the temperate land surface of the Earth and are widely used as pasture. It has been suggested that high animal stocking rates and the resulting elevated nitrogen input increase N(2)O emissions. Internationally agreed methods to upscale the effect of increased livestock numbers on N(2)O emissions are based directly on per capita nitrogen inputs. However, measurements of grassland N(2)O fluxes are often performed over short time periods, with low time resolution and mostly during the growing season. In consequence, our understanding of the daily and seasonal dynamics of grassland N(2)O fluxes remains limited. Here we report year-round N(2)O flux measurements with high and low temporal resolution at ten steppe grassland sites in Inner Mongolia, China. We show that short-lived pulses of N(2)O emission during spring thaw dominate the annual N(2)O budget at our study sites. The N(2)O emission pulses are highest in ungrazed steppe and decrease with increasing stocking rate, suggesting that grazing decreases rather than increases N(2)O emissions. Our results show that the stimulatory effect of higher stocking rates on nitrogen cycling and, hence, on N(2)O emission is more than offset by the effects of a parallel reduction in microbial biomass, inorganic nitrogen production and wintertime water retention. By neglecting these freeze-thaw interactions, existing approaches may have systematically overestimated N(2)O emissions over the last century for semi-arid, cool temperate grasslands by up to 72 per cent.

SummaryThe German government has adopted a law that requires sewage plants to go beyond the recovery of phosphorus from wastewater and to promote recycling. We argue that there is no physical global short‐ or mid‐term phosphorus scarcity. However, we also argue that there are legitimate reasons for policies such as those of Germany, including: precaution as a way to ensure future generations’ long‐term supply security, promotion of technologies for closed‐loop economics in a promising stage of technology development, and decrease in the current supply risk with a new resource pool.

Use of a pilot-scale fixed-film bioreactor was investigated for remediation of bromate contamination within groundwater. Bromate reduction with stoichiometric production of bromide was observed, providing supporting evidence for complete reduction of bromate with no production of stable intermediates. Reduction of 87-90% bromate from an influent concentration of 1.1 mg L(-1) was observed with retention times of 40-80 h. Lower retention times led to decreases in bromate reduction capability, with 11.5% removal at a 10 h retention time. Nitrate reduction of 76-99% from a 30.7 mg L(-1) as NO(3)(-) influent was observed at retention times of 10-80 h, although an increase in nitrite production to 2.7 mg L(-1) occurred with a 10 h retention time. Backwashing was not required, with the large plastic packing media able to accommodate biomass accumulation without decreases in operational efficiency. This study has provided proof of concept and demonstrated the potential of biological bromate reduction by fixed-film processes for remediation of a bromate contaminated groundwater source.

Abstract A small reverse osmoisis (RO) plant supplied by a photovoltaic (PV) power supply has been installed at the island of Gran Canaria. On behalf of this system the feasibility of small PV-RO systems (1 m3/d) is investigated. The RO-plant is described in detail concerning its technical specifications, its operation constraints and its energy demand. Furthermore the photovoltaic power supply is described in detail. With simulations it is shown how the system is designed to guarantee a reliability of more than 96% in the water supply. A brief economic analysis shows that the water production costs are still high (about 16 $/m3) but can be lowered in future.

The phosphate (P) fertilizer industry generates a highly hazardous and acidic wastewater. The present study reports the evaluation of an integrated precipitation and Enhanced Biological Phosphorus Removal (EBPR) process for the treatment of fertilizer plant wastewater and effluent detoxification, assessed by microtoxicity and seed germination tests. Effluent samples were collected from a local P fertilizer industry and were characterized by their high fluoride and P content. First, the samples were pre‐treated by precipitation of P and fluoride ions using hydrated lime. The resulting low‐fluoride and phosphorus effluent was then treated with the EBPR process to monitor the simultaneous removal of carbon, nitrogen, and phosphorus. Phosphorus removal included a two‐stage anaerobic/aerobic system operating under continuous flow. Pre‐treated wastewater was added to the activated sludge and operated for 160 days in the reactor. The operating strategy included increasing the organic loading rate from 0.3 to 1.2 g chemical oxygen demand (COD)/L day. The stable and high removal rates of COD, NH4+‐N, and PO43−‐P were then recorded. The mean concentrations of the influent were approximately 3600 mg COD/L, 60 mg N/L and 14 mg P/L, which corresponded to removal efficiencies of approximately 98%, 86%, and 92%, respectively. The microtoxicity of the treated wastewater was then monitored by LUMIStox and its phytotoxicity was investigated on cress, tomato, wheat, maize, ryegrass, and alfalfa seed germination. LUMIStox tests showed that treatment allowed a significant toxicity removal. Moreover, the untreated wastewater inhibited the species germination even when diluted 10 times, whereas a positive effect of treated wastewater was noticed. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 463–471, 2014

Mercury (Hg) represents a growing environmental and health major concern. It originates from natural sources and mainly from anthropogenic processes and it is widely distributed in the natural media. According to the last Global Mercury Assessment (2013), annual global emissions from both sources were estimated to be from 5,000 to 8,000 metric tons per year. Among the different mercury species released to the environment, methylmercury (MeHg) is considered as the most toxic form due to its ability to bioaccumulate, being then threatening even at very low concentrations.Its presence depends onHg(II) bioavailability and global amount.This explains the urgent need to ensure a continuous Hg(II) monitoring. Many efforts have been made in order to develop reliable systems able to deliver quick data and to comply with low detection limits, in accordance with the threshold value delivered by the World Health Organization (1µg L-1/ 5 nM). Spectroscopic techniques such as CV-AFS and CV-AAS are routinely used for Hg(II) determination. Although these methods can afford good sensitivity and low concentrations determination, they require sample preparation step, complex procedures and expensive material, which limits their use for on-site measurements. In this context, electrochemical sensors present excellent candidates for in situ Hg(II) trace analysis, taking in account their numerous advantages compared to spectroscopic techniques: easier handling, simple procedure, low energy consuming, low cost material and portability. In this work, we will propose a new electrochemical approach aiming to conceive and optimize an electrochemical Hg(II) sensor. The method consists in the functionalization of a glassy carbon electrode (GC) with gold nanoparticles (AuNPs) and Diazonium Salts. The main idea is to combine the interesting properties of both AuNPs and Diazonium salts. AuNPs were chosen for their electrocatalytic effect, large surface area, mass transport enhancement and for the strong affinity to mercury which will improve the sensor sensitivity. On the other hand, diazonium salts are used to improve the sensor stability by anchoring the AuNPs to the GC surface. First, nanometricorganic layer were grafted of the polished GC surface, by electrochemical reduction of 1.5 mM4-thiophenol diazonium (SH) using Constant Potential Electrolysis (CPE) in 0.1 M HCl solution at -0.55 V for 300 seconds. Electrochemical characterization performed by Cyclic Voltammetry (CV) and redox probes (ferricyanide and hexaamineruthenium(III)) revealed a total suppression of the signal, confirming the formation of a continuous blocking layer. This was confirmed by Atomic Force Microscopy (AFM)used to estimate the layer thickness, which was found to be 4 nm. Second, AuNPs were electrodeposited, for the first time, onto the diazonium multilayer by CPE in NaNO3 solution containing 0.25 mM HAuCl4for 300 seconds. Once more, redox probes were used to characterize the resulting interface and a total signal restauration and enhancement was observed after AuNPs electrodeposition, which highlights the effective AuNPs onto the organic layers. Field emission gun scanning microscopy (FEG-SEM) was used to provided further evidence and to quantify particle size and density of the AuNPs deposits. Both size and density are dependent on the CPE duration. Small homogeneous AuNPs with 27±3 nm average diameter and 158 NPs/µm2density were observed when the CPE was carried out during 300 seconds, while larger particles with 63±6 nm average diameter and lower density (63 NPs/µm2) were obtained when a longer CPE duration (600 seconds) is used. Finally, AuNPs were activated by cyclic voltammetry in H2SO4 prior to Hg(II) detection in order to homogenize the surface and to rearrange the crystallographic plans of the AuNPs. Herein, the well-known gold oxides reduction peak was observed and used to calculate the electroactive surface area (ESA) of the functionlized electrode. The electrochemical response of the final generated GC/SH/AuNPs interface towards Hg(II) was recorded by Square Wave Anodic Stripping Voltammetry (SWASV) in 0.01 M HCl solution containing different amounts of Hg(II). The SWASV procedure consists on the Hg(II) preconcentration at the electrode surface followed by the preconcentrated Hg(0) reoxidation in Hg(II). Under optimized conditions, and for a preconcentration time of 300 seconds, a well-defined peak, corresponding to Hg(0) reoxidation, was observed around 0.5 V/ECS. The sensor showed a linearity range from 1 up to 10 nM and allowed to reach picomolar level. The stability in HCl, phosphate buffer and air was also studied over several weeks: Once a week, the activation procedure was performed and followed by Hg(II) determination in order to evaluate the analytical performances of the sensor over time. Finally, Hg(II) detection assays were conducted in natural water samples collected from different sampling points. Figure 1

Alpine grasslands on the Qinghai-Tibetan Plateau are sensitive and vulnerable to climate change and human activities. Climate warming and overgrazing have already caused degradation in a large fraction of alpine grasslands on this plateau. However, it remains unclear how human activities (mainly livestock grazing) regulates vegetation dynamics under climate change. Here, alpine grassland productivity (substituted with the normalized difference vegetation index, NDVI) is hypothesized to vary in a nonlinear trajectory to follow climate fluctuations and human disturbances. With generalized additive mixed modelling (GAMM) and residual-trend (RESTREND) analysis together, both magnitude and direction of climatic (in terms of temperature, precipitation, and radiation) and anthropogenic impacts on NDVI variation were examined across alpine meadows, steppes, and desert-steppes on the Qinghai-Tibetan Plateau. The results revealed that accelerating warming and greening, respectively, took place in 76.2% and 78.8% of alpine grasslands on the Qinghai-Tibetan Plateau. The relative importance of temperature, precipitation, and radiation impacts was comparable, between 20.4% and 24.8%, and combined to explain 66.2% of NDVI variance at the pixel scale. The human influence was strengthening and weakening, respectively, in 15.5% and 14.3% of grassland pixels, being slightly larger than any sole climatic variable across the entire plateau. Anthropogenic and climatic factors can be in opposite ways to affect alpine grasslands, even within the same grassland type, likely regulated by plant community assembly and species functional traits. Therefore, the underlying mechanisms of how plant functional diversity regulates nonlinear ecosystem response to climatic and anthropogenic stresses should be carefully explored in the future.