Active Tectonics and Seismic Zonation of the Urban Area of Florence, Italy

—?The city of Florence possesses a concentration of cultural and artistic treasures which is unique in the world. In this sense it has a particularly high seismic exposure and a potentially high vulnerability. In order to better evaluate its seismic hazard and risk, we analyzed the seismic response of the urban area of Florence by performing a multidisciplinary study on the effects of earthquakes on the city. By a computer aided methodology we re-evaluated the seismic intensity reports of the May 18 and June 6, 1895 earthquakes in different parts of the city and compared these data with recent studies on surface geology, active tectonics and actual fault movements in the Florence basin. We concluded that more detailed studies of soil response are needed to form a basis for public policy.     

Protection of a monumental building against traffic-induced vibrations

To preserve an ancient building in Rome against traffic-induced vibrations, an anti-vibration system was introduced under the paving of the near Lungotevere road. An experimental investigation was recently carried out by ENEA in order to analyse the traffic-induced vibrations in the basement of the building and the effectiveness of the intervention. Wave propagation in the soil around the building in presence of the anti-vibration paving was compared with that in absence of the anti-vibration paving. The study showed the importance of the taking into account the contribution of other structures in the area to the dynamic behaviour of the whole system.     

Model sensitivity experiments on data assimilation,downscaling and tides for the representation of the Cape São Tomé Eddies

Ocean Dynamics - The impacts of data assimilation, downscaling, and tidal forcing were investigated with focus on the representation of the Cape São Tomé Eddy (CSTE). Sea level anomaly...     

The key role of the sea urchin Diadema aff. antillarum in controlling macroalgae assemblages throughout the Canary Islands (eastern subtropical Atlantic): an spatio-temporal approach

Diadema aff. antillarum performs a key role in organizing and structuring rocky macroalgae assemblages in the Canary Islands. Densities of D. aff. antillarum higher than 2 individuals m(-2) are found to drastically reduce non-crustose macroalgal cover to below 30% and wave exposure appears as a major factor determining sea urchin density, which decreases with exposure level. Substrates containing >20% sand limit urchin to under 1 individual m(-2) but high relief rocky habitats show higher density. Moreover, several anthropogenic factors (number of islanders and tourists per coastal perimeter, and number of operational fishing boats) were positively correlated with urchin abundance. A trend of increasing urchin density through time was found, although well structured marine systems found at Mar de Las Calmas Marine Protected Area and at the no-take area of La Graciosa Marine Protected Area do not seem to follow this general trend.     

Pingüino In-bearing polymetallic vein deposit,Deseado Massif,Patagonia, Argentina: characteristics of mineralization and ore-forming fluids

The Pingüino deposit, located in the low sulfidation epithermal metallogenetical province of the Deseado Massif, Patagonia, Argentina, represents a distinct deposit type in the region. It evolved through two different mineralization events: an early In-bearing polymetallic event that introduced In, Zn, Pb, Ag, Cd, Au, As, Cu, Sn, W and Bi represented by complex sulfide mineralogy, and a late Ag–Au quartz-rich vein type that crosscut and overprints the early polymetallic mineralization. The indium-bearing polymetallic mineralization developed in three stages: an early Cu–Au–In–As–Sn–W–Bi stage (Ps₁), a Zn–Pb–Ag–In–Cd–Sb stage (Ps₂) and a late Zn–In–Cd (Ps₃). Indium concentrations in the polymetallic veins show a wide range (3.4 to 1,184 ppm In). The highest indium values (up to 1,184 ppm) relate to the Ps₂ mineralization stage, and are associated with Fe-rich sphalerites, although significant In enrichment (up to 159 ppm) is also present in the Ps₁ paragenesis associated with Sn-minerals (ferrokesterite and cassiterite). The hydrothermal alteration associated with the polymetallic mineralization is characterized by advanced argillic alteration within the immediate vein zone, and sericitic alteration enveloping the vein zone. Fluid inclusion studies indicate homogenisation temperatures of 308.2–327°C for Ps₁ and 255–312.4°C for Ps₂, and low to moderate salinities (2 to 5 eq.wt.% NaCl and 4 to 9 eq.wt.% NaCl, respectively). δ³⁴S values of sulfide minerals (+0.76‰ to +3.61‰) indicate a possible magmatic source for the sulfur in the polymetallic mineralization while Pb isotope ratios for the sulfides and magmatic rocks (²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb ratios of 17.379 to 18.502; 15.588 to 15.730 and 38.234 to 38.756, respectively) are consistent with the possibility that the Pb reservoirs for both had the same crustal source. Spatial relationships, hydrothermal alteration styles, S and Pb isotopic data suggest a probable genetic relation between the polymetallic mineralization and dioritic intrusions that could have been the source of metals and hydrothermal fluids. Mineralization paragenesis, alteration mineralogy, geochemical signatures, fluid inclusion data and isotopic data, confirm that the In-bearing polymetallic mineralization from Pingüino deposit is a distinct type, in comparison with the well-known epithermal low sulfidation mineralization from the Deseado Massif.     

Is net ecosystem production higher in natural relative to constructed wetlands?

Ecosystem metabolism is an important measure of wetland restoration efficiency, and serves to indicate if the system is capable of processing energetic resources. Despite its value, ecosystem metabolism has rarely been included in monitoring programs. In this study, we aimed to achieve the following objectives: (i) compare net ecosystem production (NEP) rates of constructed vs. natural wetlands; (ii) identify the highest NEP rate habitats; and (iii) define the main environmental factors regulating NEP in different wetland types. Pelagic and benthic NEP rates and physicochemical features were measured in three natural and five constructed wetlands in the middle Ebro River floodplain (NE Spain). Statistical analyses showed pelagic NEP rates peaked in natural wetlands, which produced up to 187.5 mg C m^?3 h^?1 compared to lower rates in constructed wetlands (up to 46.2 mg C m^?3 h^?1). Pelagic NEP responded positively to temperature, total dissolved solids, and nutrients. Benthic NEP rates were 3 to 30-fold greater than pelagic in natural (up to 994.9 mg C m^?3 h^?1) and constructed (up to 1,551.5 mg C m^?3 h^?1) wetlands, and were heavily influenced by habitat type, with NEP peaking in areas dominated by submerged vegetation and fine organic sediment. Rapid recovery in aquatic communities (i.e. macroinvertebrate diversity) has been previously reported for the studied wetlands; however, our study suggests a slower recovery of functional processes (i.e. pelagic NEP) in constructed habitats. We therefore strongly advocate the inclusion of ecosystem function in the design and evaluation of restoration projects to optimise long-term wetland ecosystem sustainability.     

Efficiency of calcein tagging on juveniles of the sea urchins Diadema africanum and Paracentrotus lividus

We evaluated the effectiveness of chemical tagging with the fluorescent marker calcein for two key species of herbivorous sea urchins, Diadema africanum and Paracentrotus lividus, to facilitate medium‐ and long‐term ecological experiments. In total, 98 juveniles of D. africanum and 98 P. lividus were tagged with this fluorescent marker, with 12 combinations of different tagging techniques (chemical bath or injection), concentrations of calcein (2, 10 and 20 mg · l^?1), and soaking times (2, 4 and 24 h). Respective control treatments were conducted by means of seawater injection and bathing. The success of tagging was assessed after a month of feeding individuals ad libitum with the algae Dictyota sp. Sea urchins were dissected and their Aristotle's lanterns cleaned with 10% sodium hypochlorite to examine these structures under UV light using a binocular microscope. Each species was evaluated in terms of survival, percentage of tagged individuals and intensity of the resulting tag. The results showed that the method of soaking individuals of both species for 24 h in concentrations of calcein of 10 and 20 mg · l^?1 gave the highest percentage survival (100%) and the resulting tags were clearly visible.     

Lithological classification assisted by the joint inversion of electrical and seismic data at a control site in northeast Mexico

In this paper, evidence is presented that the combination of geospectral images and geophysical signatures (resistivity–velocity cross-plots) is a good tool to provide a natural visualization of the distribution and variations of lithological features in a test site. This was confirmed by the correlation between the electrical resistivity and seismic velocity values obtained after cross-gradient joint inversion at two profiles and geotechnical information provided by shallow boreholes in a site located in the Earth Sciences School grounds in Linares, Northeastern Mexico. The results obtained from this study show how the cross-gradient joint inversion facilitates the analysis of hydrological estimates and assists in lithological classification of subsurface materials.