A revisitation of TRIX for trophic status assessment in the light of the European Water Framework Directive: application to Italian coastal waters     

Pettine M  Casentini B  Fazi S  Giovanardi F  Pagnotta R 《Marine pollution bulletin》2007,54(9):1413-1426

The trophic status classification of coastal waters at the European scale requires the availability of harmonised indicators and procedures. The composite trophic status index (TRIX) provides useful metrics for the assessment of the trophic status of coastal waters. It was originally developed for Italian coastal waters and then applied in many European seas (Adriatic, Tyrrhenian, Baltic, Black and Northern seas). The TRIX index does not fulfil the classification procedure suggested by the WFD for two reasons: (a) it is based on an absolute trophic scale without any normalization to type-specific reference conditions; (b) it makes an ex ante aggregation of biological (Chl-a) and physico-chemical (oxygen, nutrients) quality elements, instead of an ex post integration of separate evaluations of biological and subsequent chemical quality elements. A revisitation of the TRIX index in the light of the European Water Framework Directive (WFD, 2000/60/EC) and new TRIX derived tools are presented in this paper. A number of Italian coastal sites were grouped into different types based on a thorough analysis of their hydro-morphological conditions, and type-specific reference sites were selected. Unscaled TRIX values (UNTRIX) for reference and impacted sites have been calculated and two alternative UNTRIX-based classification procedures are discussed. The proposed procedures, to be validated on a broader scale, provide users with simple tools that give an integrated view of nutrient enrichment and its effects on algal biomass (Chl-a) and on oxygen levels. This trophic evaluation along with phytoplankton indicator species and algal blooms contribute to the comprehensive assessment of phytoplankton, one of the biological quality elements in coastal waters.  相似文献   

Stability of C₆₀ and C₇₀ fullerenes toward corpuscular and γ radiation     

Franco Cataldo  Giovanni Strazzulla  Susana Iglesias-Groth 《Monthly notices of the Royal Astronomical Society》2009,394(2):615-623

The stability of C₆₀ and C₇₀ fullerenes in the interstellar medium deposited on dust surface or embedded in meteorites and comets has been simulated with γ irradiation and with He⁺ ion bombardment. It is shown by vibrational spectroscopy that a γ radiation dose of 2.6 MGy (1 Gy = 1 joule absorbed energy per kilogram) causes partial oligomerization of both C₆₀ and C₇₀ fullerenes. Oligomers are made by fullerene cages chemically connected each other which can yield back free fullerenes by a thermal treatment. The amount of irreversibly polymerized fullerenes caused by 2.6 MGy as deduced as the toluene insoluble fraction has been determined as 1.7 and 15 per cent by weight, respectively, for C₆₀ and C₇₀ fullerene. The radiation dose generated by radionuclides decay and expected to be delivered to fullerenes buried at a depth of more than 20 m in comets and meteorites is about 3 MGy per 10⁹ yr. Since fullerenes are by far resistant to such radiation dose they can survive for at least some billion years inside comets and meteorites and in fact have been detected inside certain carbonaceous chondrites. On the other hand, the direct exposure of fullerenes to cosmic rays for instance when they are adsorbed or deposited on the surface of carbon dust corresponds to the delivery of a radiation dose comprised between 30 and 65 MGy per 10⁹ yr. Experimental bombardment of both C₆₀ and C₇₀ fullerenes for instance with He⁺ ions has shown that the complete amorphization occurs at about 250 MGy. Thus in ∼4 Gyr exposure to cosmic rays it is expected a complete amorphization.  相似文献   

Discussion of ‘Deformation during exhumation of medium‐ and high‐grade metamorphic rocks in the Variscan chain in northern Sardinia (Italy) by Carosi et al.’     

Franco Marco Elter  Matteo Padovano 《Geological Journal》2010,45(4):481-482

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Recent Trends Towards Oligotrophication of the Northern Adriatic: Evidence from Chlorophyll <Emphasis Type="Italic">a</Emphasis> Time Series     

Patricija Mozetič  Cosimo Solidoro  Gianpiero Cossarini  Giorgio Socal  Robert Precali  Janja Francé  Franco Bianchi  Cinzia De Vittor  Nenad Smodlaka  Serena Fonda Umani 《Estuaries and Coasts》2010,33(2):362-375

The results of the updated and quality-checked data base of field observations on chlorophyll a (Chl a) collected in the period 1970–2007 in the Northern Adriatic Sea are presented. From the last decade, SeaWiFS satellite information was also considered. Results demonstrate a global tendency towards Chl a reduction in the period of investigation, which is more marked in the eutrophic area under the influence of the Po River. In the rest of the basin, which presents meso- or oligotrophic characteristics, long-term changes are more difficult to detect. The long-term field dataset can be divided into two periods: the last decade characterized by the strong decrease observed in the whole northern Adriatic and the earlier period with no or slight increase. The recent substantial reduction of Chl a concentrations is confirmed all over the basin (−0.11 mg m⁻³ year⁻¹) from satellite-derived information. Results are consistent with recently evidenced decrease in concentrations of phosphate and ammonia and point to the existence of oligotrophication in the Northern Adriatic. Results indicate forcefully that the still common perception of the Adriatic Sea as a very eutrophic basin is no longer appropriate, at least for its northern part and in recent years.  相似文献   

A new approach to landslide geomorphological mapping using the Open Source software in the Olvera area (Cadiz, Spain)     

Franco Mantovani  Francisco Javier Gracia  Pietro Domenico de Cosmo  Andrea Suma 《Landslides》2010,7(1):69-74

This paper presents the preliminary results of a geomorphological survey of the Olvera area (Cadiz province, Betic Ranges, Spain) and the use of the Geographic Information System (GIS) Open Source (OS) software plus Database Management System (DBMS) for making available and distributing the landslide data over the Web. In the geomorphologic survey, different landforms have been identified in the area, including structural, anthropogenic, fluvial, karst, and slope forms. In particular, the majority of the slope forms are complex (from topple to rotational slides and falls), but there are also minor forms like debris flows and mudslides. To manage geomorphological data, an Open Source GIS was used, which contained the following components: QuantumGIS, System for Automated Geoscientific Analyses (SAGA), GIS and Geographic Resources Analysis Support System (GRASS), GIS for Digital Elevation Model (DEM) generation. A key aim was to make the project-derived data available over the Web. This was achieved using MapServer which allows for the representation of the derived geospatial data with pMapper providing the graphical Web interface. Our study highlights the process dynamics of run-off erosion in Olvera derived through the use of advanced computer-based mapping tools. The resulting map products and interpretations are available via the Internet. To date, derivative maps have been produced to improve maintenance of roads and transport and of the construction of new infrastructure.  相似文献   

Butyltin compounds,sterility and imposex assessment in Nassarius reticulatus (Linnaeus, 1758), prior to the 2008 European ban on TBT antifouling paints,within Basque ports and along coastal areas     

J. Germán Rodríguez  Itziar Tueros  Ángel Borja  Javier Franco  J. Ignacio García Alonso  Joxe Mikel Garmendia  Iñigo Muxika  Cristina Sariego  Victoriano Valencia 《Continental Shelf Research》2009,29(8):1165-1173

Levels of imposex (superimposition of male characters, upon females) and the presence of sterile females are assessed in the gastropod Nassarius reticulatus (L.), at 35 locations in the Basque Country. At 18 of these localities, organotin bioaccumulation (tributyltin (TBT); dibutyltin; monobutyltin) was evaluated, using isotope dilution GC–ICP–MS. Higher imposex levels and TBT body burden were found in confined harbours, with large vessel traffic or the presence of an offshore fleet. The highest values were found for the port of Pasaia, near to a shipyard (a relative penis size index of up to 92%, and TBT body burden up to 405 ng g^?1 – given on a dry weight basis as Sn). Imposex effects were evaluated also in parasitized females, at some of the sampling sites. The percentage of presence of c-type Vas Deferens sequence stages (i.e., with vas deferens beginning at the oviduct opening) was higher in parasitized females. In turn, there was an absence of highly convoluted oviduct in parasitized females.  相似文献   

Chronology and dispersal characteristics of recently (last 5000 years) erupted tephra of Cotopaxi (Ecuador): implications for long-term eruptive forecasting     

F. Barberi  M. Coltelli  A. Frullani  M. Rosi  E. Almeida 《Journal of Volcanology and Geothermal Research》1995,69(3-4)

Cotopaxi, the highest active volcano on earth and one of the most dangerous of Ecuador is constituted by a composite cone made up of lava and tephra erupted from the summit crater. The activity of the present volcano begun with large-volume plinian eruptions followed by a succession of small-volume lava emissions and pyroclastic episodes which led to the edification of a symmetrical cone. The growth of the cone was broken by an episode of slope failure, the scar of which is now obliterated by recent and historical products. Volcanic history, eruptive frequency and characteristics of the activity were investigated by studying the stratigraphy of tephra and carrying out fifteen new ¹⁴C dating on paleosols and charcoals. The investigated period is comprised between the slope failure and the present. The deposit of the volcanic landside (dry debris avalanche of Rio Pita), previously believed to be between 13,000 and 25,000 yr B.P., is now considered to have an age slightly older than 5000 yr B.P. The stratigraphy of tephra of the last 2000 years reveals the existence of 22 fallout layers. Seven of them were dated with ¹⁴C whereas three were ascribed to the eruptions of 1534, 1768 and 1877 on the basis of comparison with historical information.Maximum clast size distribution (isopleths) of 9 tephra layers points out that the sustained explosive eruptions of Cotopaxi during the last 2000 years are characterized by very high dispersive power (plinian plumes with column heights between 28 and 39 km) and high intensity (peak mass discharges from 1.1 to 4.1 × 10⁸kg/s). The magnitude (mass) of tephra fallout deposits calculated from distribution of thickness (isopaches) are, however, moderate (from 0.8 to 7.2 × 10¹¹ kg). The limited volume of magma erupted during each explosive episode is consistent with the lack of caldera collapses. Small-volume pyroclastic flows and surges virtually accompanied all identified tephra fallouts. During such an activity large scale snow/ice melting of the summit glacier produced devastating mudflows comparable in scale to those of 1877 eruption. By assuming a 1:1 correspondence between fallout episodes and generation of large-scale lahar, we have estimated an average recurrence of one explosive, lahartriggering event every 117 years over the last two millennia. This value compares well with that calculated by considering the period since Spanish Conquest. The probability of having an eruption like this in 100 or 200 years is respectively of 0.57 and 0.82. Such an high probability underscores the need for quick actions aimed at the mitigation of Cotopaxi lahar hazard along all the main valleys which originate from the volcano.  相似文献   

The campanian ignimbrite: a major prehistoric eruption in the Neapolitan area (Italy)     

F. Barberi  F. Innocenti  L. Lirer  R. Munno  T. Pescatore  R. Santacroce 《Bulletin of Volcanology》1978,41(1):10-31

A geological, chemical and petrographical study of the Campanian ignimbrite, a pyroclastic flow deposit erupted about 30,000 years ago on the Neapolitan area (Italy), is reported. The ignimbrite covered an area of at least 7,000 km²; it consists of a single flow unit, and the lateral variations in both pumice and lithic fragments indicate that the source was located in the Phlegraean Fields area. Textural features, areal distribution and its morphological constraints suggests that the eruption was of the type of highly expanded low-temperature pyroclastic cloud. The original composition was strongly modified by post-depositional chemical changes involving most of the major and trace elements. No primary differences in the composition of the magma have been recognized. The Campanian ignimbrite is a nearly saturated potassic trachyte, similar to many other trachytes of the Quaternary volcanic province of Campania. Its chemistry indicates an affinity with the so-called «low-K association» of the Roman volcanic province.  相似文献   

Silicic peralkaline volcanic rocks of the afar depression (Ethiopia)   总被引：1，自引：0，他引：1  

F. Barberi  R. Santacroce  J. Varet 《Bulletin of Volcanology》1974,38(2):755-790

Three main types of recent volcanism may be distinguished in the Afar Depression: 1) oceanic volcanism of the axial ranges; 2) volcanism along the margins where an attenuated sialic crust probably occurs; 3) mainly fissural volcanism of Central-Southern Afar, with associated central volcanoes, similar as a whole to the volcanism of the Ethiopian Rift Valley. Peralkaline silicic volcanic rocks are found in all the three groups but showing some different characteristics which seem related to their geological location and which probably reflect different sources. Moreover emplacement of peralkaline granitic bodies, associated with volcanics of the same composition, marks the first stage of formation of the Afar Depression, in the Early Miocene. Axial Ranges: Erta’Ale and Boina volcanic ranges indicate that peralkaline rocks are the final liquids produced by fractionation of basalt in shallow magma chambers of central volcanoes. The parental magma is a transitional type of basalt with a mildly alkalic affinity, which fractionated under lowpH₂O-pO₂ conditions. Transition to peralkaline liquids is realized without passing a «true» trachytic (low silica) stage. The first peralkaline liquid is a low silica comendite and evidence exists that «plagioclase effect» was active in determining the first peralkalinity. Within the peralkaline field a fractionation mainly controlled by alkali feldspar progressively increases the peralkalinity and silica oversaturation of residual liquids (transition from comendites to pantellerites). The most peralkaline pantellerites of Boina are produced by fractionation of an alkali feldspar of constant composition (Ab_65–68 Or_35–32) suggesting that these liquids lie on a «low temperature zone» of the peralkaline oversaturated system. Marginal Units: On the borders of the depression peralkaline silicics are found in volcanic massifs mainly made of metaluminous silicic products. Petrology and geochemistry suggest a complex origin. Crystal fractionation, contamination with sialic crust and chemical changes related to a volatile rich phase, all these processes probably played a role in the genesis of these peralkaline silicic rocks. Central-Southern Afar Fissural Volcanism: Mildly alkaline basalts are associated with peralkaline and metaluminous silicics; intermediate rocks are very scanty. Fractionation from deep seated magmatic bodies with selective eruptivity and partial melting at depth of associated basalts or of a common source material are possible genetic mechanisms.  相似文献   

Recommendations for further studies on the peralkaline oversaturated volcanic rocks     

R. Macdonald  D. K. Bailey  F. Barberi 《Bulletin of Volcanology》1974,38(2):828-860

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