Variable within-brood maternal provisioning in newly extruded embryos of Homarus gammarus

Offspring quality of decapod crustaceans has been widely studied, with special emphasis on the sources of variability determining embryonic and larval quality. Nevertheless, maternal provisioning has commonly been overlooked as a potential source of offspring within-brood variability. In the present study, the existence of variable maternal provisioning was assessed through the analysis of the fatty acid (FA) profile of newly extruded embryos from different regions of the brooding chamber of Homarus gammarus. Significant differences in the FA profile of embryos sampled from different pleopods and sides of the brooding chamber were recorded. Significant deviations of the overall mean of each surveyed female were also observed for essential FA, particularly 20:4n-6, 20:5n-3 and 22:6n-3. Lipid energy available to fuel embryogenesis also varied among embryos sampled from different regions of the brooding chamber. Results suggest variable female investment at oocyte production, which may be amplified during the incubation period of developing embryos by differential lipid catabolism. For the first time, maternal provisioning is evidenced as an additional source for within-brood variability in the FA profile of embryos.     

Characterization of fulvic acids during olive mill waste composting (Elemental,Thermal and fluorescence analyses)

Elemental analysis, fluorescence spectroscopy and differential scanning calorimetry (DSC) were applied to the study of fulvic acids isolated from different stages during olive mill waste composting. The fulvic extracted acids are characterized by a high nitrogen content and O/C ratio values that may result from the high degree of humification and the synthesis of more condensed humic complexes. This was confirmed by fluorescence spectroscopy in the synchronous-scan mode by the decrease of shoulder intensities at intermediate wavelengths indicating the increase of polycondensation and conjugation of unsaturated structures and the greater uniformity of fluorophores. Fluorescence spectra in the emission, excitation and synchronous modes became simpler with compost maturation. This was confirmed by DSC results which proved the high degree of polycondensation of aromatic nuclei of fulvic acid molecules during olive mill waste composting.     

Life history strategy of a southern European population of brown shrimp (Crangon crangon L.): evidence for latitudinal changes in growth phenology and population dynamics

This study provides a comprehensive examination of the life cycle dynamics of the brown shrimp (Crangon crangon L.) in the Mondego estuary, Portugal, a habitat located near the southern edge of the range of this species in European waters. The phenology of all life stages was documented (from the occurrence of ovigerous females, developing embryos, planktonic larvae and benthic post-larvae), and migration patterns of larvae into and out of the estuary were examined. Temperature-dependent functions of egg and larval development were combined with data on field abundance to predict the timing and magnitude of occurrence of larvae and recruits. Compared to brown shrimp at higher latitudes, southern conspecifics grow slower, mature earlier and have smaller brood sizes, and larvae have a more protracted settlement period. The Mondego estuary, besides acting as nursery area, is a dynamic platform for C. crangon to use in different stages, sizes and seasons.     

Activity patterns and predatory behavior of an intertidal nemertean from rocky shores: Prosorhochmus nelsoni (Hoplonemertea) from the Southeast Pacific

Understanding the impact of environmental stressors on predator activity is a prerequisite to understanding the underlying mechanisms shaping community structure. The nemertean Prosorhochmus nelsoni is a common predator in the mid-intertidal zone on rocky shores along the Chilean coast, where it can reach very high abundances (up to 260 ind m⁻²) in algal turfs, algal crusts, barnacle crusts, and mixed substrata. Tidal and diurnal scans revealed that the activity of P. nelsoni is primarily restricted to night and early-morning low tides and is relatively low when air temperatures are high. On average, larger worms crawled faster than smaller worms, with their maximum velocity being influenced by substratum type. Their estimated rate of predation is 0.092 prey items nemertean⁻¹ day⁻¹, just below the laboratory rate of ~0.2 amphipods nemertean⁻¹ day⁻¹ previously estimated for this species. P. nelsoni consumes a diverse spectrum of prey items (i.e., amphipods, isopods, decapods, barnacles, and dipterans) and is possibly exerting a significant influence on its prey populations. We suggest that the opportunistic predatory behavior of this intertidal predator is caused by the trade-off between immediate persistence (e.g., avoidance of desiccation) and long-term survival through successful foraging.     

An indexed dispersion criterion for testing the sex-biased dispersal of lek mating behavior of capercaillies

Traditionally it has been assumed by ecologists that the dispersion of positions with respect to leks of female capercaillies during the mating season is superior to the dispersion of positions of male capercaillies. However some recently published articles suggest the idea that dispersion is not sex-biased, but both sexes show a similar dispersion. This article introduces a mathematical model to approach the study of the above question by means of an indexed dispersion criterion. This model is developed in detail thus deriving its main mathematical properties. On this basis, the model is applied to the analysis of the motivating problem with real data of positions of leks and female and male capercaillies. The results derived by means of the model put into doubt the traditional assumption of a superior dispersion of females supporting the new theories, that is, both sexes show a similar dispersion.     

The Impact of Biodegradable Plastics in the Properties of Recycled Polyethylene Terephthalate

Journal of Polymers and the Environment - Since biodegradable materials are unwittingly mixed with synthetic materials, this work aimed to study the feasibility of reliably identifying some...     

Influence of climate on grape production and wine quality in the Rías Baixas, north-western Spain

Climate exerts an important role on grape production and wine quality. For one of the main areas protected under the denomination of origin Rías Baixas, in Galicia, Spain, we explore the relationships among grape production, wine quality, rainfall and temperature for the period 1987–2005. The influence of climatic variability was analysed in terms of the relationship between the productivity of the grapevines and the main meteorological teleconnection patterns affecting the North Atlantic region. We also investigate the daily variation in atmospheric circulation through the study of the influence of weather types derived using an automated daily classification. We consider three bioclimatic indices for viticultural zoning, Winkler and Huglin, and the hydrothermic index of Branas, Bernon and Levadoux. While significant trends were identified in the Winkler and Huglin indices, there were no significant trends in the Branas, Bernon and Levadoux index, for the period 1958–2005. For the coming decades, using the scenario A1B evaluated by the regional climate models used in the ENSEMBLES project, the positive trends of Winkler and Huglin indices continue, while Branas, Bernon and Levadoux implies a negative trend. In all cases, these trends induce significant changes in the viticulture of the region.     

Efficiency of a protected-area network in a Mediterranean region: a multispecies assessment with raptors

Three different systems of designating protected areas in a Mediterranean region in southeastern Spain were studied, referring to their effectiveness and efficiency for protecting both the breeding territories and the suitable habitat of a set of ten raptor species. Taking into consideration the varying degrees of endangerment of these species, a map of multispecies conservation values was also drawn up and superimposed on the three protected-area systems studied. In order to compare the levels of protection afforded by the three systems, we considered two indices that measured their relative effectiveness and efficiency. The effectiveness estimated the proportion of territories or optimal habitat protected by the networks while efficiency implicitly considered the area of each system (percentage of breeding territories or optimal habitat protected per 1% of land protected). Overall, our results showed that the most efficient system was that formed by the set of regional parks and reserves (17 protected breeding territories per 100 km²), although, given its small total area, it was by far the least effective (only protecting the 21% of the breeding territories of all species and 17% of the area of high conservation value). The systems formed by the Special Protection Areas (designated under the EU “Birds Directive”) and by the Special Conservation Areas (designated under the EU “Habitats Directive”) notably increased the percentages of protected territories of all species (61%) and area of high conservation value (57%), but their efficiency was not as high as expected in most cases. The overall level of protection was high for all species except for the Lesser Kestrel (Falco naumanni), an endangered falcon that inhabits pseudo-steppe and traditional agricultural habitats, which are clearly underrepresented in the protected-area network of the study region.     

A review of the distribution of particulate trace elements in urban terrestrial environments and its application to considerations of risk

We review the evolution, state of the art and future lines of research on the sources, transport pathways, and sinks of particulate trace elements in urban terrestrial environments to include the atmosphere, soils, and street and indoor dusts. Such studies reveal reductions in the emissions of some elements of historical concern such as Pb, with interest consequently focusing on other toxic trace elements such as As, Cd, Hg, Zn, and Cu. While establishment of levels of these elements is important in assessing the potential impacts of human society on the urban environment, it is also necessary to apply this knowledge in conjunction with information on the toxicity of those trace elements and the degree of exposure of human receptors to an assessment of whether such contamination represents a real risk to the city’s inhabitants and therefore how this risk can be addressed.     

Stereotypy and variation of the mating call in the Lusitanian toadfish, <Emphasis Type="Italic">Halobatrachus didactylus</Emphasis>

Signal attributes should show different degrees of variability depending on the information to be conveyed. Species identity is usually associated with stereotyped features of a signal, whereas other types of information such as individual quality and motivation are associated with signal plasticity. Lusitanian toadfish males form aggregations during the breeding season and emit a tonal advertisement call (the boatwhistle) to attract mates to their nests. We test the hypothesis that the boatwhistle can convey information both on individual identity and motivation by checking how signal parameters vary with time. We study how the physical (tide level) and social (calling alone or in a chorus) environments and male calling rate affect this advertisement signal and how all these external and internal factors (environment, social and male motivation) blend to modulate the Lusitanian toadfish’s advertisement call. Boatwhistles of each male were very stereotyped in short periods of time (minutes), but intra-male signal variability greatly increased in a longer time scale (days). Nevertheless, significant differences among males could still be found even in a long time scale. Pulse period was the acoustic feature that most contributed to discriminate among males. Tide level and male calling rate modulated boatwhistle characteristics, and there was a differential effect of tide on call attributes depending on male calling rate. Social acoustic environment only affected calling rate. These results suggest that inter-individual differences in call characteristics and call plasticity may mediate both male–male assessment and mate choice.