Triassic stretching directions in Iberia and North Africa inferred from magnetic fabrics

During the Triassic, Iberia and western North Africa displayed a unique situation in relation with the Central and North Atlantic opening and westward expansion of the Tethys. Unravelling the stretching direction in Triassic deposits of the studied area can help in our understanding of this scenario. The tectonic setting is characterized by localized basins with strong thickness variations greatly influenced by previous post‐Variscan mechanical discontinuities. In this work, we revise and compile magnetic fabric data from eight Triassic depocentres in terms of defining the stretching direction (i.e. magnetic lineation), resulting from extensional deformation of this period. Data show the importance of the opening of the Atlantic rift as the leading process during the Triassic. Dextral transtension can explain the deflection of the extensional direction observed in most studied depocentres that is caused by the activity of previous major oblique faults.     

Magnetic Basement Depth Inversion in the Space Domain

We present a total-field anomaly inversion method to determine both the basement relief and the magnetization direction (inclination and declination) of a 2D sedimentary basin presuming negligible sediment magnetization. Our method assumes that the magnetic intensity contrast is constant and known. We use a nonspectral approach based on approximating the vertical cross section of the sedimentary basin by a polygon, whose uppermost vertices are forced to coincide with the basin outcrop, which are presumably known. For fixed values of the x coordinates our method estimates the z coordinates of the unknown polygon vertices. To obtain the magnetization direction we assume that besides the total-field anomaly, information about the basement’s outcrops at the basin borders and the basement depths at a few points is available. To obtain stable depth-to-basement estimates we impose overall smoothness and positivity constraints on the parameter estimates. Tests on synthetic data showed that the simultaneous estimation of the irregular basement relief and the magnetization direction yields good estimates for the relief despite the mild instability in the magnetization direction. The inversion of aeromagnetic data from the onshore Almada Basin, Brazil, revealed a shallow, eastward-dipping basement basin.     

First record of Prorocentrum lima (Dinophyceae) inside harbor areas and along the Abruzzo region coast, W Adriatic

Prorocentrum lima (Ehrenberg) Dodge has been found for the first time during the summer of 2007 inside Ortona harbor and along the coast of the Abruzzo region, a slightly eutrophic area influenced by runoff from a nearby river. The investigations were conducted in two harbors and at six coastal sampling stations. Samplings were conducted using a phytoplankton net and with a pump. Average P. lima cellular concentrations were 3.2 × 10⁴ cells L⁻¹. Other well-known toxic and potentially toxic phytoplankton species have been considered. The number of toxic cells from net samples were higher than the numbers of toxic cell samples collected without the net. Occurrences of P. lima with abiotic factors revealed that temperature was positively correlated with P. lima abundance (p = 0.01), while salinity was highly negatively correlated with P. lima presence (p = 0.001). The total phytoplankton community was studied.     

Vibrios in association with sedimentary crustaceans in three beaches of the northern Adriatic Sea (Italy)

In the marine environment, vibrios adhere to a number of substrates including chitin-rich organisms such as crustaceans. Their wide diffusion in coastal waters and pathogenic potential require knowledge of the lifestyle and environmental reservoirs of these bacteria. To test the presence of culturable vibrios in coastal areas and their association with benthic crustaceans, vibrios were isolated from water, sediments and crustaceans (copepods and anphipods) at three stations placed in front of heavily used tourist beaches of the Adriatic Sea. We observed significant correlations between vibrios and temperature. Benthic and planktonic copepods harboured vibrios in summer, while benthic amphipods harboured these bacteria in spring and autumn. Vibrio alginolyticus and Vibrio parahaemolyticus strains gave positive results using primers for Vibrio cholerae toxR and toxS. Sedimentary crustaceans may extend Vibrio persistence in seawater and may represent an additional aquatic reservoir of these bacteria.     

An Advanced Puff Model Based On A Mixed Eulerian/Lagrangian Approach For Turbulent Dispersion In The Convective Boundary Layer

An advanced model aimed at describing the problem of dispersion in theconvective boundary layer is proposed. The pollutant particles are groupedin clusters and modelled as Gaussian puffs. The expansion of each puff ismodelled according to the concept of relative dispersion and expressed interms of the spectral properties of the energy containing eddies of the turbulent field. The centre of mass of each puff is moved along a stochastic trajectory, obtained using a Lagrangian stochastic model and filtering the velocity with a recursive Kalman filter. At any instant, a filtering procedure, depending both on travel time and on puff size, acts to select spectral components involved in the expansion and in the meandering of the puff. Such an approach requires only a moderate number of puff releases, so that the proposed model is faster to run than a standard Lagrangian model. On the other hand, unlike the traditional puff model, it allows us to simulate both expansion and meandering of the puff. Therefore, it is well suited to simulate dispersion when the turbulent structures are larger thanthe plume dimensions, as for example in convective conditions. Being based onspectral formulations in both Eulerian and Lagrangian parts, the model is consistent in all the turbulent parameterizations utilised. Comparisons with a standard Lagrangian particle model as well as with a classical convective experimental dataset show good performance of the proposed model.     

Comparative Magnetotelluric Modeling of Smooth 2D and 3D Conducting Bodies Using Rayleigh-Fourier Codes

—Recently, a method for 3D magnetotelluric modeling was developed, which is based on the application of the Rayleigh scattering theory. This method, RF-3D, is especially capable of modeling multilayered structures with smooth irregular boundaries. The formulation allows inclusion of layers with vertically anisotropic electrical conductivity.¶Using RF-3D, the response of smooth structures of practical interest is calculated and the importance of 3D effects is evaluated. Two models consisting of a 3D conductive body in the presence of a 2D shallow distortion are analyzed. In the first model, the direction of maximum elongation of the body is perpendicular to the strike direction of the 2D upper structure, and in the second one both directions coincide. In addition, the case of a small 3D shallow conductor over a regional 2D structure is also considered.¶3D effects are compared to those generated by 2D models with identical cross sections. In all the cases, the 3D responses differ from those of the 2D, especially directly over the bodies. A good agreement between the 2D transverse magnetic response and the corresponding components of the 3D response, along centrally located transverse profiles, is expected for elongate, prismatic conductors. Then, the differences obtained for the models considered in this study, particularly for the second and third models, are a consequence of the smooth geometry. They can be explained in terms of galvanic effects produced by boundary charges, which are greater near the vertical sides of a prism than on the sides of a body with smooth contours.¶Equivalent 2D models of the first and second structures are also obtained. In these models, the thickness of the conductor is underestimated, respectively, by about 30% and 24%.¶For the third model, when vertical anisotropy is analyzed, it is found that only the anisotropy of the first layer can be detected. This is because the effect of vertical anisotropy decreases strongly with depth and appears to be important only near the 3D anomaly.     

Modeling biodiversity benefits and external costs from a keystone predator reintroduction policy

In this paper, an economic model was constructed to determine the optimal wolf population and distribution across the Northern Rocky Mountains. Both ecological and economic concepts were incorporated in an implicitly spatial social welfare maximization problem. This interdisciplinary model relies on multiple data sources, including current wolf population and distribution information, opportunity cost to local landowners, and contingent valuation studies to determine willingness-to-pay for wolves. Economic models tend to externalize ecological concerns and ecological models often omit the complex human dimensions of conservation policy. Accordingly, this model can serve as a guide for integrating best practices from both fields. The model presented here is sufficiently general to apply to wolves in other ecosystems and to other highly interacting species such as beavers and bison. The Northern Rocky Mountain wolf was used as an example of how this economic model works, but this model can be applied far more broadly.     

Improved prediction of vegetation composition in NW European softwater lakes by combining location,water and sediment chemistry

Isoetids, as indicators of near-pristine softwater lakes, have a high priority in national and international (European Water Directive Framework) assessments of ecological lake quality. Our main goal was to identify the most important environmental factors that influence the composition of plant communities and specifically determine the presence and abundance of the isoetid Lobelia dortmanna in NW European softwater lakes. Geographical position and composition of surface water, porewater, sediment and plant communities were examined in 39 lakes in four regions (The Netherlands, Denmark, West Norway and East Norway) distributed over a 1,200-km long distance. We confirmed that lake location was accompanied by significant changes in environmental variables between NW European lakes. Lake location was the single most important determinant of vegetation composition and it had significant individual contributions independent of the coupling to environmental variables. This influence of location was supported by a significant decline of community similarity with geographical distance between pairs of lakes at regional, inter-regional and international scales. Combining the geographical position with environmental variables for surface water, porewater and sediment significantly improved prediction of vegetation composition. Specifically, the combination of latitude, surface water alkalinity, porewater phosphate and redox potential offered the highest correlation (BIO ENV correlation 0.66) to vegetation composition. This complex analysis can also account for high sediment variability in the littoral zone of individual lakes, by using site-specific physico-chemical sediment factors, and offer better predictions of vegetation composition when lake water chemistry is relatively homogeneous among lakes within regions.     

Life history of Cornularia cornucopiae (Anthozoa: Octocorallia) on the Conero Promontory (North Adriatic Sea)

The life cycle of the stoloniferan Cornularia cornucopiae (Pallas, 1766) (Anthozoa: Octocorallia) was studied from March 2009 to October 2010 on the rocky cliff of the Conero Promontory (North Adriatic Sea, 43°34.865′ N, 13°34.320′ E). In this area the species showed unusual high densities never recorded in other sites of the Mediterranean Sea. The density trend of the species showed a marked seasonal cycle, with a winter minimum of about 1000 polyps m^?2 and a summer maximum of about 30,000 polyps m^?2. In accordance with other Mediterranean literature data, polyps were fertile during spring–summer, from March to August, but the number of eggs per polyp continuously decreased during this span of time. Variations of polyp density were strongly correlated to water temperature, which can be considered the main environmental factor triggering this seasonal behaviour. The possibility, for C. cornucopiae, to face adverse winter conditions is probably related to the presence of a characteristic perisarcal envelope covering the stolon and the calyx of each polyp, which isolates the living tissues from the exterior. During winter, polyps degenerate but the stolons remain dormant inside their envelopes. The perisarc covering represents a morphological convergence of C. cornucopiae with benthic hydrozoans. As the latter, the studied stoloniferans are able to live in habitats characterized by periodic favourable conditions thanks to a seasonal life strategy. A similar trend is shared also by other important components (cnidarians and some sponges) of the filter‐feeding community of the North Adriatic Sea. Differently to the Western Mediterranean basin, this area is characterized by high food availability all year around, so benthic organisms are strongly constrained by the very low winter temperatures.     

Associations between outdoor air quality and birth weight: a geostatistical sequential simulation approach in Coastal Alentejo,Portugal

Several environmental health studies suggest birth weight is associated with outdoor air pollution during gestation. In these studies, exposure assignments are usually based on measurements collected at air quality monitoring stations that do not coincide with health data locations. So, estimated exposures can be misleading if they do not take into account the uncertainty of exposure estimates. In this article we conducted a semi-ecological study to analyze associations between air quality during gestation and birth weight. Air quality during gestation was measured using a biomonitor, as an alternative to traditional air quality monitoring stations data, in order to increase spatial resolution of exposure measurements. To our knowledge this is the first time that the association between air quality and birth weight is studied using biomonitors. To address exposure uncertainty at health locations, we applied geostatistical simulation on biomonitoring data that provided multiple equally probable realizations of biomonitoring data, with reproduction of observed histogram and spatial covariance while matching for conditioning data. Each simulation represented a measure of exposure at each location. The set of simulations provided a measure of exposure uncertainty at each location. To incorporate uncertainty in our analysis we used generalized linear models, fitted simulation outputs and health data on birth weights and assessed statistical significance of exposure parameter using non-parametric bootstrap techniques. We found a positive association between air quality and birth weight. However, this association was not statistically significant. We also found a modest but significant association between air quality and birth weight among babies exposed to gestational tobacco smoke.