Trophic impact, metabolism, and biogeochemical role of the marine cladoceran Penilia avirostris and the co-dominant copepod Oithona nana in NW Mediterranean coastal waters

In this work we studied the trophic ecology and feeding impact of the cladoceran Penilia avirostris and the cyclopoid copepod Oithona nana, the two dominant zooplankters in the summer communities of the coastal NW Mediterranean, on the naturally occurring microbial communities. In order to ascertain carbon surplus for growth and reproduction and the contribution to carbon and nitrogen recycling of these two species, we also determined their basal metabolism and excretion rates. The experiments conducted during summers 2002, 2003, and 2004 indicate that P. avirostris grazed mostly upon small flagellates, dinoflagellates, and diatoms, whereas O. nana had a narrower prey range, selecting motile organisms such as ciliates and occasionally dinoflagellates. The grazing impact of both species accounted, on average, for <10% of the standing stock of the microbial groups considered. In spite of the oligotrophic conditions, the feeding activity of P. avirostris is in general sufficient to compensate basal metabolism and allows a surplus for growth and reproduction. This was not the case for O. nana, its daily rations being often lower than the carbon basal demands. Regarding excretion rates, both species presented different N:P excretion ratios, the ones of O. nana falling within values typical for copepods, whereas the absence of detectable phosphorus excretion by P. avirostris implied an unbalance recycling with respect to typical Redfield ratio composition of marine seston.     

Screening-level ecological risk assessment of polychlorinated dibenzo-p-dioxins and dibenzofurans in sediments and aquatic biota from the Venice Lagoon, Italy

Recent monitoring data indicate that portions of Italy's Venice Lagoon ecosystem have been degraded due to biological and chemical pollution from a variety of potential sources. Using polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) data collected from sediment, fish and shellfish in the Lagoon, a screening-level ecological risk assessment (ERA) was performed to evaluate the risks to representative aquatic biota and wildlife receptors. Risks to aquatic invertebrates posed by PCDD/Fs in sediment were evaluated by comparing measured tissue concentrations in fish and shellfish to appropriate ecotoxicological reference values. For mammalian and avian receptors, risks posed by theoretical exposures to PCDD/Fs through the food chain were calculated using conservative wildlife exposure models. Results of the screening-level approach indicate that the potential for adverse effects to fish and aquatic invertebrate receptors from PCDD/Fs in surficial sediments are unlikely. Adverse effects to wildlife are possible but highly uncertain, and warrants further investigation in a more comprehensive ERA.     

Including risk in stated-preference economic valuations: Experiments on choices for marine recreation

Stated-preference surveys for the economic valuation of environmental resources typically assume no uncertainty in the hypothetical valuation scenarios. However, the outcomes of environmental policies are uncertain. We explored the effects of including information on probabilities of attribute improvement and provision in choice experiments. Our results suggest that stating explicitly a high probability for the occurrence of the valuation scenario can improve the goodness of fit of choice models and the consistency of choices. As the general public becomes more aware of the uncertainty of environmental outcomes under global change, omitting information on scenario risk may contribute to hypothetical bias and impair the validity of stated-preference valuations.     

Lay perceptions of carbon capture and storage technology

The extent of social acceptance of carbon capture and storage (CCS) is likely to significantly influence the sustainable development of CO₂ storage projects. Acceptance of CCS by the key stakeholders (policy makers, the general public, the media and the local community), linked to specific projects, as well as how the technology is communicated about and perceived by the public, have become matters of interest for the social sciences. This article reports on an investigation of the public perception of CCS technology in Spain. Individuals’ views on CCS are analysed through focus groups with lay citizens using “stimulus materials”. As the analysis shows, lay views of CCS differ significantly from the views of decision-makers and experts. Public concerns and reactions to CCS technology and potential projects, as well as the degree of consensus on its acceptance or rejection are detailed. Implications for the future use of CCS are discussed.     

Purification of carbonic anhydrase from bovine erythrocytes and its application in the enzymic capture of carbon dioxide

This work presents a study of industrially applicable techniques to obtain a biologically supported carbon dioxide capture system, based on the extraction of carbonic anhydrase from bovine blood. Carbonic anhydrase is a metalloenzyme which catalyzes the reversible hydration of carbon dioxide. The objective of this study was to establish conditions to obtain carbonic anhydrase from bovine erythrocytes and apply it in the capture of carbon dioxide. To achieve this, two different purification techniques were evaluated: one by extraction with the organic solvents chloroform and ethanol, where different solvent proportions were studied; and the other by ammonium sulfate precipitation, testing percent saturations between 10% and 80%. Carbon dioxide was enzymatically captured by its precipitation as calcium carbonate with the enzyme obtained by both techniques. The enzyme extracted by ethanol and chloroform showed an activity of 2623 U mL⁻¹, recovery of 98% and purification factor of 104-fold. That precipitated by ammonium sulfate showed an activity of 2162 U mL⁻¹, recovery of 66% and purification factor of 1.4-fold using 60% ammonium sulfate saturation. The results obtained in the carbon dioxide capture experiments showed that the carbonic anhydrase extracted in this study not only enhanced the hydration of CO₂, but also promoted the formation of CaCO₃.     

Electrochemical incineration of indigo. A comparative study between 2D (plate) and 3D (mesh) BDD anodes fitted into a filter-press reactor

This paper compares the performance of 2D (plate) and 3D (mesh) boron-doped diamond (BDD) electrodes, fitted into a filter-press reactor, during the electrochemical incineration of indigo textile dye as a model organic compound in chloride medium. The electrolyses were carried out in the FM01-LC reactor at mean fluid velocities between 0.9?≤?u?≤?10.4 and 1.2?≤?u?≤?13.9 cm s^?1 for the 2D BDD and the 3D BDD electrodes, respectively, at current densities of 5.63 and 15 mA cm^?2. The oxidation of the organic matter was promoted, on the one hand, via the physisorbed hydroxyl radicals (BDD(^●OH)) formed from water oxidation at the BDD surface and, on the other hand, via active chlorine formed from the oxidation of chloride ions on BDD. The performance of 2D BDD and 3D BDD electrodes in terms of current efficiency, energy consumption, and charge passage during the treatments is discussed.     

Textiles for health: a review of textile fabrics treated with chitosan microcapsules

Environmental Chemistry Letters - The&nbsp;textile industry has recently&nbsp;been developing innovative products that integrate functional properties within commodity textiles. In...     

Mapping Cumulative Environmental Risks: Examples from the EU NoMiracle Project

We present examples of cumulative chemical risk mapping methods developed within the NoMiracle project. The different examples illustrate the application of the concentration addition (CA) approach to pesticides at different scale, the integration in space of cumulative risks to individual organisms under the CA assumption, and two techniques to (1) integrate risks using data-driven, parametric statistical methods, and (2) cluster together areas with similar occurrence of different risk factors, respectively. The examples are used to discuss some general issues, particularly on the conventional nature of cumulative risk maps, and may provide some suggestions for the practice of cumulative risk mapping.