Interaction between shallow and deep aquifers in the Tivoli Plain (Central Italy) enhanced by groundwater extraction: A multi-isotope approach and geochemical modeling     

Valentina Carucci  Marco PetittaRamon Aravena 《Applied Geochemistry》2012

In the Tivoli Plain (Rome, Central Italy) the interaction between shallow and deep groundwater flow systems enhanced by groundwater extraction has been investigated using isotopic and chemical tracers. A conceptual model of the groundwater flowpaths has been developed and verified by geochemical modeling. A combined hydrogeochemical and isotopic investigation using ion relationships such as DIC/Cl⁻, Ca/(Ca + Mg)/SO₄/(SO₄ + HCO₃), and environmental isotopes (δ¹⁸O, δ²H, ⁸⁷Sr/⁸⁶Sr, δ³⁴S and δ¹³C) was carried out in order to determine the sources of recharge of the aquifer, the origin of solutes and the mixing processes in groundwater of Tivoli Plain. Multivariate statistical methods such as principal component analysis and Cluster analyses have confirmed the existence of different geochemical facies and the role of mixing in the chemical composition of the groundwater.  相似文献   

Anomalous birefringence in andradite–grossular solid solutions: a quantum-mechanical approach     

Valentina Lacivita  Philippe D’Arco  Roberto Orlando  Roberto Dovesi  Alessio Meyer 《Physics and Chemistry of Minerals》2013,40(10):781-788

The static linear optical properties (refractive indices, birefringence and axial angle) of andradite–grossular (Ca₃Fe₂Si₃O₁₂–Ca₃Al₂Si₃O₁₂) solid solutions have been computed at the ab initio quantum-mechanical level through the Coupled Perturbed Kohn–Sham scheme, using an all-electron Gaussian-type basis set. Geometry relaxation after substitution of 1–8 Al for Fe atoms in the primitive cell of andradite yields 23 non-equivalent configurations ranging from cubic to triclinic symmetry. Refractive indices vary quite regularly between the andradite (1.860) and grossular (1.671) end-members; the birefringence δ and the axial angle 2V at intermediate compositions can be as large as 0.02° and 89°, respectively. Comparison with experiments suffers from inhomogeneities and impurities of natural samples; however, semi-quantitative agreement is observed.  相似文献   

DNA damage in the gill cells of the marine scallop Mizuhopecten yessoensis during anoxic stress and aerobic recovery   总被引：2，自引：0，他引：2  

Valentina V. Slobodskova  Avianna F. Zhukovskaya  Victor P. Chelomin 《Ocean Science Journal》2012,47(2):95-100

Anoxia-induced DNA damage in the gill cells of the marine scallop Mizuhopecten yessoensis was assessed with the alkaline comet assay (single-cell gel electrophoresis). The alkaline comet assay method for detecting DNA strand breaks and alkali labile sites in individual cells. DNA damage was determened in the scallops (M. yessoensis) gill cells. The scallops were exposed to air for 8 h showing a clear increase in the levels of DNA damage. After the air exposure, M. yessoensis were re-submersed for a period of 12 h, leading values to return to a pre-aerial exposure level. Control animals were kept immersed during the whole period. The resulting data demonstrate that natural influences, such as oxygen depletion (anoxia) in seawater, can be responsible for the induction of DNA damage. If the scallops were re-immersed in oxic conditions, the anoxically induced breaks were repaired. The main mechanisms influencing the integrity of the DNA structure are discussed in this paper.  相似文献   

Mediterranean warming is especially due to summer season   总被引：2，自引：2，他引：0  

Giorgio Bartolini  Valentina di Stefano  Giampiero Maracchi  Simone Orlandini 《Theoretical and Applied Climatology》2012,107(1-2):279-295

We created a new homogenized daily minimum and maximum temperature data set (1955–2007) for the central Mediterranean area of Tuscany (Italy). Yearly and seasonal long-term trends of some climatic and extreme climatic indices were investigated. The results highlighted a positive trend for mean temperature of about 0.9°C per 50 years with a slightly more pronounced increase in maximum temperature. Seasonal analysis revealed a by far much greater increase in summer (June, July, August) and spring (March, April, May) temperature in respect of autumn and winter, this finding consistent with most recent Mediterranean evidences. Warm extremes showed an overall tendency to increase, while a slight not significant decrease trend was found in regard to frost days and cold extremes. Comparisons with different patterns of Mediterranean warming confirmed the magnitude of recent very fast rise in temperature, especially during summer. This change could be due to last decades modifications of general circulation patterns and land–temperature, land–precipitation positive feedback processes dependent from soil moisture. All these results confirm that the Mediterranean is a region especially responsive and thus very vulnerable to climate change.  相似文献   

High‐resolution synchrotron X‐ray fluorescence investigation of calcite coralloid speleothems: Elemental incorporation and their potential as environmental archives     

Valentina Vanghi  Andrea Borsato  Silvia Frisia  Daryl L. Howard  Gertruida Gloy  John Hellstrom  Petra Bajo 《Sedimentology》2019,66(7):2661-2685

Synchrotron high‐resolution and micro‐X‐ray fluorescence elemental mapping of two coeval coralloid speleothems from Lamalunga Cave (Italy) are complemented with petrographic, morphological and microstratigraphic studies. The importance of these speleothems relies on their direct and indirect association with a complete Neanderthal skeleton (‘Altamura Man’) found inside the cave. The coralloids grew discontinuously between 64·6 ka and the Holocene and reveal exceptionally high concentrations of Mg, Sr and Si, particularly on convex surfaces, where evaporation is more intense. The incorporation of trace elements depends on several factors including location, shape and geometrical evolution during their growth, as well as climate and environmental parameters. This resulted in calcite precipitation with Sr compositions from 100 to 1200 ppm and an average concentration of 7000 ppm Mg. An unusually high Si content (up to 16%) is possibly derived from volcanic ash transported as particulate and in solution inside the cave. The most common fabrics observed consist of non‐fluorescent elongated columnar calcite forming clean isopachous bands and fluorescent fibre‐like crystals associated with laminated, lenticular bands high in Sr, Mg and Si. Variability in Sr, Mg and Si concentrations appears to induce fabric changes in the coralloids. Elongation and lattice distortion of the crystals was found to coincide with high Mg concentrations. The transition from compact elongated to open to fibre‐like, is here interpreted as due to high concentrations of Si and Sr, which are preferentially incorporated in the speleothem at crystal boundaries and intra‐laminae. It is here inferred that coralloid fabric changes and their elemental content potentially record local rainfall variations through time, with the clean compact calcite marking high infiltration and open fibre‐like and micrite fabrics recording dry periods.  相似文献   

Using tracer tests and hydrological observations to evaluate effects of tunnel drainage on groundwater and surface waters in the Northern Apennines (Italy)   总被引：1，自引：0，他引：1  

Valentina Vincenzi  Alessandro Gargini  Nico Goldscheider 《Hydrogeology Journal》2009,17(1):135-150

The impact of a railway tunnel on groundwater and surface waters in the Northern Apennines (Italy) was demonstrated and characterised by multi-tracer tests and hydrological observations. The 15-km-long Firenzuola tunnel crosses turbidite marls and sandstones previously not considered as aquifers. During the drilling, water inrushes occurred at fracture zones, and the tunnel still continues to drain the aquifer. The water table dropped below the level of the valleys, and gaining streams transformed into losing streams or ran completely dry, as did many springs, causing severe damage to the aquatic fauna and other elements of the ecosystem. Two multi-tracer tests, each using uranine and sulforhodamine G, were carried out in two impacted catchments in order to confirm and quantify the stream–aquifer–tunnel interrelations. The results proved connection between losing streams and numerous water inlets in the tunnel, with maximum linear distances of 1.4 km and velocities up to 135 m/d. Several of the demonstrated flowpaths pass under previous groundwater divides (mountain ridges), proving that the tunnel has completely modified the regional flow system. Water balance estimations demonstrate that the observed water losses cannot be explained by climate change but can largely be attributed to the tunnel drainage.  相似文献   

Geophysical investigations of the plumbing system of Stromboli volcano (Aeolian Islands,Italy)     

Mario Mattia  Marco Aloisi  Giuseppe Di Grazia  Salvatore Gambino  Mimmo Palano  Valentina Bruno 《Journal of Volcanology and Geothermal Research》2008

In this work, we report the results of an integrated approach using both seismological and geodetic data provided by the INGV-CT (Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania) Stromboli volcano monitoring systems, in order to improve the knowledge of its plumbing system. In particular, we investigated the relationships between the June 1999 seismic swarm, occurring in the area of Stromboli, and the possible activation of the NE–SW oriented volcano-tectonic structure. We analyzed this seismic swarm proposing new locations and a morphological analysis of the waveforms. This approach allowed us to demonstrate that there are relationships between the tectonic activity near Stromboli and the rising of magma. This evidence supports the hypothesis that during the 1999 swarm an intrusive process started from a crustal level where earthquakes were located (about 10–15 km b.s.l.).  相似文献   

Magnetic indicator of global paleoclimate cycles in Siberian loess–paleosol sequences     

Vadim A. Kravchinsky  Valentina S. Zykina  Vladimir S. Zykin 《Earth and Planetary Science Letters》2008,265(3-4):498-514

The loess–paleosol sequences of China, Siberia, Alaska and many other regions, along with lake sediments and glaciers, provide the only accurate paleoclimatic terrestrial records for intervals of thousands to hundreds of thousand years. The frequency dependence (FD) of magnetic susceptibility (MS) in such sequences has become the leading parameter for analyzing climatic change and Milankovitch (astronomical) periodicity in Siberian sequences; it is always higher in soil horizons than in loess. The enhanced FD parameter in soils is associated with ferromagnetic minerals, mostly magnetite, produced during pedogenesis. The MS and FD parameters of 670 samples from five sections in Siberia are reported here. Inter-section correlation is used to produce a combined FD time series for the studied sections. Chronological control is established by absolute dating and stratigraphic correlation. Spectral analysis of the FD time series reveals the presence of Milankovitch signals at ～100 kyr (eccentricity), ～40 kyr (obliquity) and ～23 kyr (precession) and demonstrates that Siberian loess–paleosol sequences are excellent continental recorders of long-term paleoclimatic changes. This suggests that the FD parameter can potentially be used more widely for evaluation of climate periodicity in loess/paleosol sequences in other parts of the world.  相似文献   

Biogeochemical effects of disturbance in shallow water sediment by macroalgae harvesting boats     

Lenzi M  Finoia MG  Persia E  Comandi S  Gargiulo V  Solari D  Gennaro P  Porrello S 《Marine pollution bulletin》2005,50(5):512-519

In the shallow water of Orbetello lagoon, macroalgae harvesting boats produce sediment disturbance. To evaluate the effect of this, during 2001-2002, a trial study was carried out in the lagoon in order to: verify seasonal and diurnal trends in nutrients and estimate the quantity of resuspended organic sediment. An unbalanced and balanced ANOVA (one and two way) analysis was applied. The disturbance did not produce strong and lasting eutrophication effects. In the seasonal survey, dissolved inorganic nitrogen (DIN) and soluble reactive phosphorus (SRP) showed significant decreases in disturbed areas at the end of the trial, while the control area showed a constant, significant increase. Dissolved organic nitrogen (DON) and phosphorus (DOP) significantly increased everywhere. In disturbed areas, sediment redox (Eh((NHE))) increased and porosity values decreased, contrary to the control area. Total organic carbon (TOC) remained unchanged in disturbed areas, but increased in the control area, where the C:P ration increased. The fall-out of sedimentary material resuspended by boat action for as far as 50 m from the boat route, was 189 g(dw)m(-2) made up mainly of organic matter. This disturbance could be the cause of change in vegetation in the lagoon.  相似文献   

Monitoring a Marine Coastal Area: Use of Mytilus galloprovincialis and Mullus barbatus as Bioindicators     

Ilaria Corsi  Michela Mariottini  Valentina Menchi  Christiana Sensini  Cristiana Balocchi  Silvano Focardi 《Marine Ecology》2002,23(S1):138-153

Abstract. Samples of Mytilus galloprovincialis and Mullus barbatus were collected in eight coastal sites along the South Adriatic and Ionic coasts of Italy in spring 2000 for a survey of coastal pollution in the Mediterranean basin. Specimens were analysed using an integrated approach based on residue analysis of common aquatic pollutants like organochlorines such as hexachlorobenzene (HCB), DDTs and polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), heavy metals and nonylphenols (NPnE) and biomarker responses such as acetylcholinesterase (AChE) activity, and the two specific P450 activities benzo(a)pyrene monooxygenase (BPMO) and 7-ethoxyre-sorufin-(9-deethylase (EROD). Biological and morphological parameters like somatic liver index (SLI), gonadosomatic index (GSI) and gonadal and gamete histology (eggs and sperms) were also evaluated in red mullet samples. A contamination gradient in which several hot spots occur were revealed in this study. The hot spots account for high levels of organochlorines in both species near incinerators and of PAHs in harbour areas. Levels of both NPnE and AChE activity were highest in two protected marine areas and were within detectable limits in others. This finding was confirmed by P450 activities, in which maximum levels were detected in harbours and protected marine areas. No morphological alterations of male and female gonads were observed on the histological level.  相似文献