Sublethal responses in caged organisms exposed to sediments affected by oil spills

This study was performed to determine sublethal responses of two invertebrate species by using field deployments in areas affected by oil spills, which are acute in the Galician Coast (NNW, Spain) and chronic in the Bay of Algeciras (SSW, Spain). The organisms employed were the crab Carcinus maenas and the clam Ruditapes philippinarum, and during 28 days the animals were exposed to contaminated sediments in cages under field conditions. Different biomarkers of exposure were determined after a 28-day period exposure: ethoxyresorufin O-deethylase (EROD), phase I detoxification enzyme, glutathione-S-transferase (GST) phase II detoxification enzyme but also implicated in oxidative stress events, glutathione peroxidase (GPX) and glutathione reductase (GR), both antioxidant enzymes. In addition, histopathological effects in target tissues of the deployed organisms were evaluated. Biomarker measurements were linked with the concentration of chemicals in the sediments in order to elucidate the type, source and bioavailability of contaminants that produce adverse effects in the bioindicator species. Results obtained in this study have shown how the application of the selected battery of biomarkers under field bioassays allows for the identification of alternative sources of stress that are not observable in laboratory experiments.     

Perceptions of Wood in Rivers and Challenges for Stream Restoration in the United States

This article reports a study of the public perception of large wood in rivers and streams in the United States. Large wood is an element of freshwater aquatic ecosystems that has attracted much scientific interest in recent years because of its value in biological and geomorphological processes. At the heart of the issue is the nature of the relationship between scientific recognition of the ecological and geomorphological benefits of wood in rivers, management practices utilizing wood for river remediation progress, and public perceptions of in-channel wood. Surveys of students’ perceptions of riverscapes with and without large wood in the states of Colorado, Connecticut, Georgia, Illinois, Iowa, Missouri, Oregon, and Texas suggest that many individuals in the United States adhere to traditionally negative views of wood. Except for students in Oregon, most respondents considered photographs of riverscapes with wood to be less aesthetically pleasing and needing more improvement than rivers without wood. Analysis of reasons given for improvement needs suggest that Oregon students are concerned with improving channels without wood for fauna habitat, whereas respondents elsewhere focused on the need for cleaning wood-rich channels for flood risk management. These results underscore the importance of public education to increase awareness of the geomorphological and ecological significance of wood in stream systems. This awareness should foster more positive attitudes toward wood. An integrated program of research, education, and policy is advocated to bridge the gap between scientific knowledge and public perception for effective management and restoration of river systems with wood.     

Options for National Parks and Reserves for Adapting to Climate Change

Past and present climate has shaped the valued ecosystems currently protected in parks and reserves, but future climate change will redefine these conditions. Continued conservation as climate changes will require thinking differently about resource management than we have in the past; we present some logical steps and tools for doing so. Three critical tenets underpin future management plans and activities: (1) climate patterns of the past will not be the climate patterns of the future; (2) climate defines the environment and influences future trajectories of the distributions of species and their habitats; (3) specific management actions may help increase the resilience of some natural resources, but fundamental changes in species and their environment may be inevitable. Science-based management will be necessary because past experience may not serve as a guide for novel future conditions. Identifying resources and processes at risk, defining thresholds and reference conditions, and establishing monitoring and assessment programs are among the types of scientific practices needed to support a broadened portfolio of management activities. In addition to the control and hedging management strategies commonly in use today, we recommend adaptive management wherever possible. Adaptive management increases our ability to address the multiple scales at which species and processes function, and increases the speed of knowledge transfer among scientists and managers. Scenario planning provides a broad forward-thinking framework from which the most appropriate management tools can be chosen. The scope of climate change effects will require a shared vision among regional partners. Preparing for and adapting to climate change is as much a cultural and intellectual challenge as an ecological challenge.     

Assessing visitor satisfaction with tourism rejuvenation policies: the case of Rimini,Italy

This paper assesses the appeal of potential interventions on the tourism offer of Rimini, a popular Italian seaside holiday destination, by means of a choice modelling analysis. Tourism can be viewed as a composite good, its overall utility depending on the arrangement of the component characteristics. The discrete choice experiments here incorporate as attributes a number of possible changes to current tourist activities (the subject of public debate), including them in hypothetical alternative holiday packages. The conditional logit analysis indicates that tourists show lesser preference for interventions aimed at protecting the environmental integrity of the beach and greater preference for those, such as the creation of a pedestrianised seafront with late-night opening of amenities and facilities, that are likely to diminish the role of the traditional sea, sun and sand component of the overall holiday experience.     

Development and validation of an objective intra‐organizational career success measure for managers

This study aimed to develop and validate a new objective measure of intra‐organizational career success, that is the Managerial Career Success Measure (MCSM). Although there has been a recent emphasis in the careers literature on the subjective career, there is still a need for a valid operationalization of ‘traditional’, objective career success as this construct is still considered relevant by many occupational and national groups; furthermore, many studies continue to use objective career success as a (dependent) variable. With regard to content validity, it appears that the measure that was developed incorporates some elements of the commonly used measures of objective career success (i.e. managerial level, number of promotions, salary and salary progression) while steering clear of some of the issues with each of them separately. Concurrent and discriminant validity were explored by analysing data from three empirical studies that were carried out in a large heterogeneous managerial population (N = 1101). Results indicate that the MCSM displays higher levels of content and construct validity than do other, commonly used measures of objective career success. Copyright © 2008 John Wiley & Sons, Ltd.     

Application of flow field-flow fractionation and laser sizing to characterize soil colloids in drained and undrained lysimeters

This paper reports the use of a new technique, flow field-flow fractionation (FlFFF), for the characterization of soil sampled under grassland. FlFFF can be used to determine the fine colloidal material in the <1 microm fraction obtained by gravitational settling of 1% m/v soil suspensions. The aim of this work was to determine the potential of FIFFF to characterize soil colloids in drained and undrained field lysimeters from soil cores sampled at different depths. Two different grassland lysimeter plots of 1 ha, one drained and one undrained, were investigated, and the soil was sampled at 20-m intervals along a single diagonal transect at three different depths (0-2, 10-12, and 30-32 cm). The results showed that there was a statistically significant (P = 0.05) increase in colloidal material at 30- to 32-cm depth along the transect under the drained lysimeter, which correlates with disturbance of the soil at this depth due to the installation of tile drains at 85-cm depth backfilled to 30-cm depth with gravel. Laser sizing was also used to determine the particles in the size range 1 to 2000 microm and complement the data obtained using FlFFF because laser sizing lacks resolution for the finer colloidal material (0.1-1.0 microm). The laser sizing data showed increased heterogeneity at 30- to 32-cm depth, particularly in the 50 to 250 microm size fraction. Therefore FIFFF characterized the finer material and laser sizing the coarser soil fraction (<2000 microm) at depth in drained and undrained grassland. This is of importance as colloidal material is more mobile than the larger material and consequently an important vector for contaminant transport from agricultural land to catchments.     

A phytochelatin-based bioassay in marine diatoms useful for the assessment of bioavailability of heavy metals released by polluted sediments

The aim of the present work was to develop a new bioassay involving the presence of phytochelatins (PCs), detoxifying intracellular metal-binding peptides, in microalgae as response to metal bioavailability in re-suspensions of metal-polluted marine sediments. For this purpose, the synthesis of PCs has been studied in laboratory cultures of three marine diatoms, namely Phaeodactylum tricornutum, Thalassiosira weissflogii and Skeletonema costatum, exposed to elutriates of sediments collected in a polluted coastal area in the province of Pisa (Tuscany, Italy). Short- and long-term incubations in the elutriates of two marine sediments (named A and B) exhibited an increase of PCs synthesis in all the phytoplanktonic species examined, when the elutriate concentration increased from 0% to 100%. Elutriate B, which was mainly contaminated by Cd, was shown to be more effective to induce PCs than elutriate A, which was richer in Cu and TOC. The results show that the PCs response, in the microalgae examined, was species-specific. Our data also show that the PCs synthesis occurred before the growth rate was affected, thereby indicating that PCs can be considered as an early warning response of metal exposure. The PCs response in exponentially growing cultures of T. weissflogii, which was found to be the most sensitive alga, increased when the initial cellular density decreased. Finally, the positive relationship obtained between the cellular PCs concentration in T. weissflogii and the degree of metal contamination of the elutriates from twelve sediments collected in a metal-polluted coastal area, confirmed that the PCs-induction test can be applied in field studies. In conclusion, the response of these marine microalgae suggests that these cellular peptides could represent an excellent biomarker of metal exposure, which is useful for the assessment of sediment toxicity, by carrying out PCs-induction tests on sediment elutriates.     

Effect of different types of clouds on surface UV-B and total solar irradiance at southern mid-latitudes: CMF determinations at Córdoba,Argentina

The effect of clouds on total and UV-B irradiance in Córdoba, Argentina, was studied employing the TUV 4.1 model and measurements obtained with YES UVB-1 and YES TSP-700 radiometers, and a spectral radiometer Ocean Optics USB-4000. The experimental measurements were selected from a 10 years dataset (1999–2008). Clouds were classified by direct observation as cirrus, cumulus, and stratocumulus. The broadband Cloud Modification Factors (CMFs) have been calculated in the range of the total and the UV-B radiation for these types of clouds. The relations between them were analyzed for a significant number of days. The broadband CMF values range from around 0.1 up to 1.25, depending on the wavelength interval and on the cloud type. The CMF_UVB versus CMF_T plots for different clouds have shown good adjustments and significant differences, which allows the distinction between them.Stratocumulus clouds show large attenuations and a linear relation with larger slopes as the solar zenith angle (SZA) increases. For this type of clouds an average slope of (1.0 ± 0.2) was found. The relation between the CMF for cumulus clouds is linear with an average slope of (0.61 ± 0.01). No dependence with the SZA was observed. Cirrus clouds plots show an exponential behavior with fit parameters equal to (0.48 ± 0.08) and (0.68 ± 0.15). However, when small SZA intervals are analyzed a linear relation is found. When the relations between the CMF were similar (cumulus and cirrus), the spectral variation in the UV range (320–420 nm) of a modified CMF (CMF_m) was used to distinguish them. Hence, the spectral differences among the three types of clouds have been also analyzed for several days and SZA. Here, it was found that the effect of cirrus is essentially wavelength independent while cumulus and stratocumulus clouds show exponential decay relations but with different ordinates.In the analyzed relations the microphysical properties of the clouds seem to determine its behavior while the optical thickness leads to the different degrees of attenuation.The results obtained in this work are in agreement with those found for other authors.     

Antioxidant responses and reactive oxygen species generation in different body regions of the estuarine polychaeta Laeonereis acuta (Nereididae)

The aim of this study was to analyze the total antioxidant capacity (TOSC), generation of reactive oxygen species (ROS) and lipid peroxidation (LPO) in the different body regions of the estuarine polychaeta Laeonereis acuta (Nereididae) sampled at non-polluted (NOPOL) and polluted (POL) sites from Lagoa dos Patos (Southern Brazil). Organisms collected at POL during summer showed similar (p>0.05) TOSC values along the body, but worms collected at NOPOL presented higher (p<0.05) TOSC values in the posterior (P) region in respect of anterior (A) region and middle (M) region. TOSC in the P region at NOPOL was higher (p<0.05) compared with the same body region of worms at POL. In summer, ROS concentration was higher in A and M regions of worms at POL in respect of the organisms at NOPOL. During winter all the regions showed higher ROS in worms sampled at POL. It was registered absence of season influence on LPO content, but in the P region at NOPOL in summer there were lower LPO levels compared with the others regions (p<0.05). In vitro assays showed that P region, despite a higher basal ROS, presented a higher competence to cope with pro-oxidants compared with A and M regions (p<0.05), corroborating the field results. A lower proteic sulfhydril content was observed in P in respect of the other regions (p<0.05) supporting the idea of a highest oxidant condition in this region. The results indicate that worms collected at the POL site are confronted to higher ROS concentrations, affecting its antioxidant capacity, a result that depends of body regions.     

A study on PCB, PCDD/PCDF industrial contamination in a mixed urban-agricultural area significantly affecting the food chain and the human exposure. Part I: soil and feed

This study deals with a PCB, PCDD and PCDF contamination in Brescia, a city in the North-West of Italy, affecting an area with about 11000 inhabitants. The area is close to an industrial plant that produced, in total, some 31,000 ton of PCB. A relevant part of the polluted area is agricultural soil, where cattle were fed with polluted forage and farmers were consuming their own products, so that contamination led eventually to human exposure. Total levels of PCDD/Fs varied from 8 to 592 pgTE(WHO)/g for soil samples and when the dioxin-like PCBs (dl-PCBs) are included, the levels varied from 14.6 to 1033.7 pgTE(WHO)/g. In several cases, the legal limit was exceeded by more than one order of magnitude, with the highest contamination in some agricultural areas and in the surrounding zones. For the forage samples, total levels of PCDD/Fs varied from 0.29 to 2.04 pgTE(WHO)/g and, when dl-PCBs are included, this range increased from 2.04 to 4.75 pgTE(WHO)/g. PCB contamination of the forage through vapor condensation seemed to be relevant. The toxic contribution of dl-PCBs is always relevant and must be considered for risk management. The main component of the contamination source is probably a heavy PCB mixture, such as Aroclor 1262. The study dealt generally with the contamination transfer of PCBs, PCDDs and PCDFs from soil up to humans across the food chain. Results on soils and forages are shown, while measurements concerning the contamination of the animals fed with contaminated forage, and the exposure of the farmers (through human serum analyses), as compared to general population, will be reported in a dedicated paper.