Study on the formation and transport of ozone in relation to the air quality management and vegetation protection in Tenerife (Canary Islands)

An experimental study on the formation and transport of ozone in ambient air was performed in Tenerife (Canary Islands) in order to investigate the processes affecting ozone levels and air quality. The special features of Tenerife (prevalence of the trade wind pattern (NE), orography and the specific location of the local ozone sources) permit to quantify the role of the ‘long-range transport from northern latitudes' versus the ‘formation and transport of ozone downwind of the main urban areas' of Tenerife. Levels of O₃, NO₂ and O_X were monitored in different types of environments to achieve this purpose. The results showed that: (1) upwind of the urban areas ozone is mainly transported from the ocean by trade winds, (2) local ozone titration (by NO) and ozone replenishment from the ocean are the main causes of ozone variations in urban and suburban areas, and (3) photochemical ozone production occurs downwind of the urban areas. Photochemical production causes daylight O₃ and O_X levels downwind of urban areas to be frequently (60% and 35% days/year, respectively) higher than upwind of the urban sites (O₃ and O_X excess frequently in the range 5–20 ppbv). Due to the above processes, different daily ozone cycles occur in short distances (<30 km), with maximum O₃ levels during daylight or night depending on the site. Ozone phytotoxicity was assessed by calculating the AOT40 index upwind and downwind of the main urban areas. The critical value for the 5-day-AOT40 index was simultaneously exceeded at the two sites (few times/year) during long-range transport events. During the additional exceedances of the critical value downwind of the urban area, relatively high 5-day-AOT40 values were recorded upwind of the urban site. Thus, long-range transport from northern latitudes may produce relatively high 5-days-AOT40 levels in the oceanic boundary layer. These results are important for the protection of the large number of endemic plants in the Canaries. The conceptual model discussed in this study may be qualitatively applied to other islands which possess features similar to those of Tenerife.     

Patterns of animal diversity in different forms of tree cover in agricultural landscapes.

As tropical regions are converted to agriculture, conservation of biodiversity will depend not only on the maintenance of protected forest areas, but also on the scope for conservation within the agricultural matrix in which they are embedded. Tree cover typically retained in agricultural landscapes in the neotropics may provide resources and habitats for animals, but little is known about the extent to which it contributes to conservation of animal species. Here, we explore the animal diversity associated with different forms of tree cover for birds, bats, butterflies, and dung beetles in a pastoral landscape in Nicaragua. We measured species richness and abundance of these four animal taxa in riparian and secondary forest, forest fallows, live fences, and pastures with high and low tree cover. We recorded over 20,000 individuals of 189 species including 14 endangered bird species. Mean abundance and species richness of birds and bats, but not dung beetles or butterflies, were significantly different among forms of tree cover. Species richness of bats and birds was positively correlated with tree species richness. While the greatest numbers of bird species were associated with riparian and secondary forest, forest fallows, and pastures with >15% tree cover, the greatest numbers of bat species were found in live fences and riparian forest. Species assemblages of all animal taxa were different among tree cover types, so that maintaining a diversity of forms of tree cover led to conservation of more animal species in the landscape as a whole. Overall, the findings indicate that retaining tree cover within agricultural landscapes can help conserve animal diversity, but that conservation efforts need to target forms of tree cover that conserve the taxa that are of interest locally. Preventing the degradation of remaining forest fragments is a priority, but encouraging farmers to maintain tree cover in pastures and along boundaries may also make an important contribution to animal conservation.     

Atmospheric particulate matter and air quality in the Mediterranean: a review

This article synthesises the results obtained in several projects on atmospheric aerosol (particulate matter – PM) pollution developed during the last years in the Western Mediterranean. It focuses on particulate matter sources and the strategies for suitable monitoring in ambient air. The article has been structured in several sections that give response to the main questions that prompted these studies. After analysing the main PM features in the Mediterranean, a brief review of the main factors differentiating the particulate matter composition with respect to Central Europe is presented. Finally, the suitability of the different metrics or parameters for monitoring ambient air PM levels in different types of environments is discussed. Selected article from the 6th European Meeting on Environmental Chemistry, University of Belgrade, Serbia and Montenegro organized by Prof. Dr. Branimir Jovancicevic (www.research.plymouth.ac.uk/ace).     

Fullerenes toxicity and electronic properties

Nanotechnology globally represents a new direction within scientific development, where the atomic and electronic properties of molecules are used in a unique fashion to produce and construct new and exotic materials and products. Fullerenes (Bucky balls, C₆₀) constitute a particular group within the field of nanotechnology. Fullerenes find applications in medicine, industrial chemistry and electronics. However, there are several unanswered questions about fullerenes and their toxicological properties. Most toxicological studies on fullerenes evolve around the in vitro and in vivo aspects of pristine C₆₀ along with chemically modified C₆₀ molecules. We reviewed toxicology reports on C₆₀. We bring a critical and challenging evaluation of the electronic and quantum properties of C₆₀ molecules in context with the implications on cellular factors and metabolites. The evaluation shows that the reactivity and quantum chemical properties of C₆₀ can have unexpected effects in the cell, by principally absorbing metabolites, such as OH^? and H⁺ ions and alter its reactivity. We thus challenge the present view of C₆₀ solely based on empirical studies, based on the electronic properties of C₆₀ that vary considerably with their size and reaction path. A further example of this is the absorption of divalent zinc ions, which shows an increase in reactivity of the C₆₀ that presents an important pattern of chemical state, reactivity and toxicological potential. The results evaluate the toxicological potential of C₆₀ from a different angle than conventional, by applying a blend of critical review of the findings on C₆₀ toxicity, their chemical and electronic properties.     

Mercury in the Mediterranean. Part 2: processes and mass balance

Mass balance of contaminants can provide useful information on the processes that influence their concentrations in various environmental compartments. The most important sources, sinks and the equilibrium or non-equilibrium state of the contaminant in individual environmental compartments can also be identified. Using the latest mercury speciation data, the results of numerical models and the results of recent studies on mercury transport and transformation processes in the marine environment, we have re-evaluated the total mercury (HgT) mass balance in the Mediterranean Sea. New calculations have been performed employing three distinct marine layers: the surface layer, the thermocline and the deep sea. New transport mechanisms, deep water formation and density-driven sinking and upwelling, were included in the mass balance calculations. The most recent data have even enabled the calculation of an approximate methylmercury (MeHg) mass balance. HgT is well balanced in the entire Mediterranean, and the discrepancies between inputs and outputs in individual layers do not exceed 20 %. The MeHg balance shows larger discrepancies between gains and losses due to measurement uncertainties and gaps in our knowledge of Hg species transformation processes. Nonetheless, the main sources and sinks of HgT (deposition and evasion) and MeHg (fluxes from sediment, outflow through the Gibraltar Strait) are in accordance with previous studies on mercury in the Mediterranean Basin. Mercury in the Mediterranean fish harvest is the second largest MeHg sink; about 300 kg of this toxic substance is consumed annually with sea food.     

Spatial distribution patterns of the soft corals Alcyonium acaule and Alcyonium palmatum in coastal bottoms (Cap de Creus, northwestern Mediterranean Sea)

Current knowledge on the abundance and distribution patterns of different soft coral species is relatively limited when compared to other benthic suspension feeders such as gorgonians and hard coral species. To overcome this scarcity of information, the distribution patterns of the soft corals Alcyonium acaule and Alcyonium palmatum were investigated in northwestern Mediterranean benthic communities over a wide geographical (60 km of coastline) and bathymetrical (0–70 m depth) extent using a remotely operated vehicle. A. acaule was the most abundant species in the study area with highest recorded density of 18 col m^?2 found at depths of 35–45 m in areas that are directly exposed to strong near-bottom currents. Conversely, A. palmatum was only found as scattered solitary colonies at greater depths in soft bottoms, with maximum density of 2.4 col m^?2. Medium and large colonies of A. acaule were preferentially found on sloping and vertical rocky bottoms where they form dense patches. High-density patches of A. acaule were preferentially found on vertical rocky bottom, while isolated colonies were preferentially observed on coralligenous substrata as well as on flat soft and maërl substrates. A. acaule biomass distribution showed highest values between 40 and 45 m depth, and between 60 and 65 m depth. This suggests that deeper populations are formed by colonies that are bigger than the equivalent shallower ones. Although both species are almost genetically identical, ecologically they are very different. For this reason, conservation plans should consider the differential ecological traits shown by these two soft coral species.     

Agricultural landscapes as multi-scale public good and the role of the Common Agricultural Policy

During the last 50 years, the Common Agricultural Policy (CAP) has impacted the evolution of European agricultural landscapes by driving changes in land use and farming practices. We propose a typology characterising the scales relevant for agricultural landscapes management and argue that action is required on three scales: (1) a landscape oriented management at the farm level; (2) the coordination of land managers’ actions at the landscape level; and (3) the conservation of the diversity of agricultural landscapes in the EU. We provide evidence that until now the CAP has mainly focused on the first scale. We also illustrate how agricultural policy could encourage coordinated actions at the landscape- and EU-scales. In particular, we propose policy instruments to coordinate actions of individual land owners (e.g. collective bonus in agro-environmental contracts or support to environmental cooperatives (scale 2)). We also analyse how the recognition and transposition of the European Landscape Convention could promote trans-frontier landscape cooperation in order, not only to conserve high-quality rural landscapes, but also to ensure the conservation of the diversity of EU landscapes (scale 3). This paper provides a knowledge base to support an integrated CAP design in the direction of improved landscape management, as an important component of the EU project towards more sustainable agriculture.     

Feeding by larvae of intertidal invertebrates: assessing their position in pelagic food webs

One of the leading determinants of the structure and dynamics of marine populations is the rate of arrival of new individuals to local sites. While physical transport processes play major roles in delivering larvae to the shore, these processes become most important after larvae have survived the perils of life in the plankton, where they usually suffer great mortality. The lack of information regarding larval feeding makes it difficult to assess the effects of food supply on larval survival, or the role larvae may play in nearshore food webs. Here, we examine the spectrum of food sizes and food types consumed by the larvae of two intertidal barnacle species and of the predatory gastropod Concholepas concholepas. We conducted replicated experiments in which larvae were exposed to the food size spectrum (phytoplankton, microprotozoan and autotrophic picoplankton) found in nearshore waters in central Chile. Results show that barnacle nauplii and gastropod veligers are omnivorous grazers, incorporating significant fractions of heterotrophs in their diets. In accordance with their feeding mechanisms and body size, barnacle nauplii were able to feed on autotrophic picoplankton (<5 microm) and did not consume the largest phytoplankton cells, which made the bulk of phytoplankton biomass in spring-summer blooms. Balanoid nauplii exhibited higher ingestion rates than the smaller-bodied chthamaloid larvae. Newly hatched C. concholepas larvae also consumed picoplankton cells, while competent larvae of this species ingested mostly the largest phytoplankton cells and heterotrophic protozoans. Results suggest that persistent changes in the structure of pelagic food webs can have important effects on the species-specific food availability for invertebrate larvae, which can result in large-scale differences in recruitment rates of a given species, and in the relative recruitment success of the different species that make up benthic communities.