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1.
Macroalgal survival in ballast water tanks   总被引：1，自引：0，他引：1  
Despite a large amount of research into invasive species and their introductions, there have been no studies focused on macroalgal transport in ballast water. To address this, we collected replicate samples of ballast water from 12 ships in two Mediterranean harbours (Naples and Salerno). Filtered samples were kept in culture for a month at Mediterranean mean conditions (18 degrees C, 12:12h LD, 60micromol photons m(-2)s(-1)). Fifteen macroalgal taxa were cultured and differed according to the geographic origin of the ballast water. Most of the cultured algae were widely distributed species (e.g. Ulva spp. and Acinetospora-phase). However, Ulva ohnoi Hiraoka and Shimada, described from Japan, was hitherto unknown in the Mediterranean Sea. We show for the first time that ballast water can be an important vector for the transport of microscopic stages of macroalgae and that this can be a vector for the introduction of alien species.  相似文献   

2.
The bacteriological quality of bathing waters is examined for two coastlines with very different environmental characteristics, namely Whitley Bay in the north east of England and the Bay of Naples in the Mediterranean. The Whitley Bay beach is contaminated by sea outfalls, but tidal action is vigorous, the water is cool and sunlight is not very strong. The water does not meet the EEC standards for bathing water quality at the present time, but a new sewerage system soon to be completed should effect a substantial improvement.In the Bay of Naples there is very little tide, the water is warm and sunlight is usually strong in the bathing season. The water quality meets the EEC standards for most of the authorized beaches and pollution is restricted to a few well defined zones in the Bay.  相似文献   

3.
Available gravity and magnetic data of the Phlegraean Fields geothermal area, Naples, Italy, have been interpreted and the obtained structural models discussed in the light of the other available geological, volcanological and geophysical data.On the basis of the results of a previous seismic reflection survey in the Gulf of Naples and in the Pozzuoli Bay, which delineated a basement characterized by a seismic velocity of 4–6 km/s, it has been possible to evaluate the gravity anomaly connected with the morphology of this horizon ( = 2.7 g/cm3).The residual anomaly map, obtained after subtraction of the regional long-wavelength components relative to mantle and deep crustal structures and the computed components relative to the above-mentioned seismic basement, shows up as a circular low with an amplitude of 10 mgal centred in the Pozzuoli Bay. This gravity low has been interpreted as due to the occurrence, in the centre of Pozzuoli Bay, of light (Δ = −0.2 g/cm3) material with a maximum thickness of about 2 km. However, a contribution to the anomaly due to a narrow magmatic body intruded in the basement, as suggested by volcanological and ground deformation data, cannot be excluded.The aeromagnetic map of the Phlegraean Fields is characterized by three main anomalies which have been fitted by superficial tridimensional parallelepipedic bodies, schematically representing lava flows and domes. Their anomalies have been subsequently subtracted from the observed field, obtaining as a residual a large anomaly centred in the southwestern area of the Pozzuoli Bay. It has been interpreted as being due to a lowmagnetized body which, taking into account the thermal state of the area, should represent that part of the pyroclastic sequence which has lost part of its magnetization by thermo-chemical alteration.  相似文献   

4.
About 190 anthropogenic sinkholes occurred within the territory of the city of Naples (Southern Italy) between 1915 and 2010.In the study area, the genesis of sinkholes can be ascribed to two major factors, often strongly interacting with each other: the existence of a complex network of underground man-made cavities, and the inadequacy of the sewage disposal system.Rainfall has been identified as the main triggering factor combined with anthropogenic activity. Based on such predisposing factors, in addition to the geological setting, a susceptibility map of the territory has been realised.  相似文献   

5.
The nearshore sediments in the Bay of Naples show a buildup of organic carbon and increased levels of lead, copper and chromium as a result of discharge of domestic and industrial waste water. Twenty to twenty-five square kilometres of bottom area have been contaminated by the buildup of anoxic muds with elevated heavy metal concentrations.  相似文献   

6.
For almost one century an important steel plant has been active at the Bagnoli industrial area (Naples, Southern Italy). The environmental survey of near shore and offshore sediments has been carried out as fundamental part of a clean up project. The characteristics of the area, supposed type of pollution, national and international protocols in force were taken into consideration in designing sampling schemes and selecting analytical parameters. For this work, sediment grain size, PAHs, PCBs, trace elements, total hydrocarbons and organic matter were considered. Factor analysis evidenced two main types of pollution in the proximity of the industrial plant, both probably attributable to the activity of the industrial site. The first one, due to Cd, Pb, Zn and Mn seems determined by localised activities at the southern part of the plant. The second one, due to Fe and Mn, appears directly linked to the whole contaminated area.  相似文献   

7.
--A distribution-free statistical approach is proposed for tackling the problem of regionalization devoted to the study of magnitude-intensity relationships in the Mediterranean area. The training-set constitutes a compilation of more than 2000 earthquakes which occurred in the Mediterranean region since the end of the nineteenth century, when instrumental data became available, with epicentral or maximum intensity S VI and MS magnitude values. Firstly an empirical magnitude-intensity correspondence has been computed for each intensity class by using the entire data set in the assumption of homogeneity at the regional scale. Residuals of such relation have been analyzed by a distribution-free statistical approach in order to evaluate the opportunity of a regionalization able to locally improve the performances of magnitude-intensity relationships. The analysis indicates that data concerning larger earthquakes (intensity S VII) do not suggest the opportunity of zonation, and that unbiased estimates of macroseismic magnitude can also be obtained in the assumption that magnitude-intensity correspondences are uniform over the entire Mediterranean area. Therefore, better constrained relations determined for the entire Mediterranean region should be preferred to ill-defined local ones. As concerns smaller events (intensity VI), the procedure suggests that medium/small-scale lateral variations (on a wavelength lower than 102 km) should be taken into account if an efficient estimate of magnitudes from maximum observed intensity is pursued, but that data presently available are not sufficient to suggest any reliable zonation of the area under study.  相似文献   

8.
A new method of tide gauge data analysis is described for detecting ground deformation in active volcanic areas. This method was tested in the Phlegraean Fields, an active volcanic area near Naples where, in 1970 after a large ground uplift, a dense tide-gauge network was installed. The results of the tide-gauge analysis were checked with levelling data, and a good agreement between the data sets has been found. The observational continuity of the tide-gauge network gave the time evolution of the ground deformation and showed short time oscillations. The good results obtained at the Phlegraean Fields using the tide-gauge network and the data analysis procedure are encouraging.  相似文献   

9.
The energy cone concept has been adopted to describe some kinds of surge deposits. The energy cone parameters (height and slope) are evaluated through a regression technique which utilizes deposit thicknesses and the correspondent quotes and heights of the energy cone. The regression also allows to evaluate a coefficient of proportionality linking the deposit thickness to the distance between topographic surface and energy line for a given eruption. Moreover, if an accurate topography is available (in this case a reconstruction of a digitalized topography of the Phlegrean Fields and of the Vesuvius), the energy cone parameters, obtained by the backfitted technique, can be used to evaluate the order of magnitude of the deposit volumes.The hazard map for a surge localized at the Solfatara (Phlegraean Fields, Naples) has been computed. The values of the energy cone parameters and the volume have been assumed to be equal to those estimated with the regression technique applied to a past surge eruption in the same area.  相似文献   

10.
Ischia is the emergent top of a large volcanic complex that rises more than 1,000 m above the sea floor, at the north-western end of the Gulf of Naples. Caldera resurgence in the central part of the island has resulted in the formation of differentially displaced blocks, among which Mt. Epomeo (787 m a.s.l.) is the most uplifted. Deformation and slope instability have been recognised as common features induced by a block resurgence mechanism that causes uplift and favours gravitational loading and flank failure. The Monte Nuovo block, a topographic high on the north-western flank of Mt. Epomeo, has recently been interpreted as a block affected by deep-seated gravitational slope deformation. This block may undergo a catastrophic failure in the case of renewal of magmatic activity. This paper investigates the potential failure of the Monte Nuovo block as a rockslide-debris avalanche, the consequent tsunami generation and wave propagation, and discusses the catastrophic effects of such an event. Mobilization-prone volume has been estimated at about 160·106 m3 and would move from a maximum elevation of 400 m a.s.l. The landslide itself would sweep away a densely populated territory as large as 3.5 km2. The highest waves generated by the tsunami, on which this paper is mainly focussed, would hit the northern and western shores of Ischia. However, the high coast would prevent inundation and limit devastation to beaches, harbours and surrounding areas. Most of the tsunami energy would head towards the north-east, hitting the Campania coast. Severe inundation would affect an area of up to 20 km2 around the mouth of the Volturno river, including the urban area of Castel Volturno. In contrast, less energy would travel towards the south, and the Gulf of Naples would be perturbed by long persisting waves of limited damaging potential.  相似文献   

11.
The flamingo Phoenicopterus ruber roseus frequents Mediterranean wetlands. In recent decades, the population of this species has increased significantly in the Mediterranean region, despite the reclamation of many wetlands. The increase is thought to reflect the opportunistic behaviour of flamingos. They visit some sites more frequently than others in response to human activities such as organic pollution, conservation measures and better management of breeding areas on the northern side of the Mediterranean. Tunisian wetlands are major wintering and nursery habitats for the flamingo that in very wet years can also become important breeding areas. These areas can support up to half the population of the western Mediterranean, which is estimated at around 80 000 to 90 000 birds. To demonstrate the changes in the wintering population in Tunisia, the key site of Essijoumi, which has up to 25 000 wintering flamingos, was selected as a case study area. It has been shown that Essijoumi, an urban wetland in Tunis, has changed from a hypersaline to a brackish waterlogged site for most of the year. The change can be traced to the recent urban extension of Tunis which led to a water balance surplus due to increased runoff and decreased agricultural land in the catchment area. Organic pollution is playing a major role in the nutrification of water resources leading to better feeding habitats. This, in turn, has influenced the distribution of flamingos and the carrying capacity of the wetland. Increased water depth to about 3 m has made the northern part of Essijoumi inaccessible. However, the southern and eastern parts of this wetland have become more attractive to flamingos and to a diversity of waterfowl. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

12.
The polycyclic aromatic hydrocarbons (PAHs) pollution in the Sarno River and its environmental impact on the Gulf of Naples (Tyrrhenian Sea, Central Mediterranean Sea) were estimated. The 16 PAHs identified by the USEPA as priority pollutants and perylene were determined in the water dissolved phase (DP), suspended particulate matter (SPM) and sediments. Total PAHs concentrations ranged from 23.1 to 2670.4 ng L(-1) in water (sum of DP and SPM) and from 5.3 to 678.6 ng g(-1) in sediment samples. Source analysis revealed that PAHs mainly came from combustion process. Contaminant discharges of PAHs into the sea were calculated in about 8530 gd(-1) showing that this river should account as one of the main contribution sources of PAHs to the Tyrrhenian Sea.  相似文献   

13.
By conducting a historical review of this large seismic event in the Mediterranean, it has been possible to identify both the epicentral area and the area in which its effects were principally felt. Ever since the nineteenth century, the seismological tradition has offered a variety of partial interpretations of the earthquake, depending on whether the main sources used were Arabic, Greek or Latin texts. Our systematic research has involved the analysis not only of Arab, Byzantine and Italian chronicle sources, but also and in particular of a large number of never previously used official and public authority documents, preserved in Venice in the State Archive, in the Marciana National Library and in the Library of the Museo Civico Correr. As a result, it has been possible to establish not only chronological parameters for the earthquake (they were previously uncertain) but also its overall effects (epicentral area in Crete, Imax XI MCS). Sources containing information in 41 affected localities and areas were identified. The earthquake also gave rise to a large tsunami, which scholars have seen as having certain interesting elements in common with that of 21 July 365, whose epicentre was also in Crete. As regards methodology, this research made it clear that knowledge of large historical earthquakes in the Mediterranean is dependent upon developing specialised research and going beyond the territorial limits of current national catalogues.  相似文献   

14.
Ocean Dynamics - A dense network of instruments has been deployed within harbors along the Mediterranean coast, in the Toulon Metropole area, between the Hyères islands and the Sanary Bay in...  相似文献   

15.
The Campanian Ignimbrite (36000 years B.P.) was produced by the explosive eruption of at least 80 km3 DRE of trachytic ash and pumice which covered most of the southern Italian peninsula and the eastern Mediterranean region. The eruption has been related to the 12-x15-km-diameter caldera located in the Phlegraean Fields, west of Naples. Proximal deposits on the periphery of the Phlegraean Fields comprise the following pyroclastic sequence from base to top: densely welded ignimbrite and lithic-rich breccias (unit A); sintered ignimbrite, low-grade ignimbrite and lithic-rich breccia (unit B); lithic-rich breccia and spatter agglutinate (unit C); and low-grade ignimbrite (unit D). Stratigraphic and componentry data, as well as distribution of accidental lithic types and the composition of pumice clasts of different units, indicate that coarse, lithic-rich breccias were emplaced at different stages during the eruption. Lower breccias are associated with fines-rich ignimbrites and are interpreted as co-ignimbrite lag breccia deposits. The main breccia unit (C) does not grade into a fines-rich ignimbrite, and therefore is interpreted as formed from a distinct lithic-rich flow. Units A and B exhibit a similar pattern of accidental lithic types, indicating that they were erupted from the same area, probably in the E of the caldera. Units C and D display a distinct pattern of lithics indicating expulsion from vent(s) that cut different areas. We suggest that unit C was ejected from several vents during the main stage of caldera collapse. Field relationships between spatter agglutinate and the breccia support the possibility that these deposits were erupted contemporaneously from vents with different eruptive style. The breccia may have resulted from a combination of magmatic and hydrothermal explosive activity that accompanied extensive fracturing and subsidence of the magma-chamber roof. The spatter rags probably derived from sustained and vigorous pyroclastic fountains. We propose that the association lithic-rich breccia and spatter agglutinate records the occurrence of catastrophic piecemeal collapse.  相似文献   

16.
The common mussel Mytilus galloprovincialis was selected as unique biomonitor species to implement a regional monitoring programme, the CIESM Mediterranean Mussel Watch (MMW), in the Mediterranean and Black Seas. As of today, and upon standardization of the methodological approach, the MMW Network has been able to quantify (137)Cs levels in mussels from 60 coastal stations and to produce the first distribution map of this artificial radionuclide at the scale of the entire Mediterranean and Black Seas. While measured (137)Cs levels were found to be very low (usually < 1 Bq kg(-1) wet wt) (137)Cs activity concentrations in the Black Sea and North Aegean Sea were up to two orders of magnitude higher than those in the western Mediterranean Basin. Such effects, far from representing a threat to human populations or the environment, reflect a persistent signature of the Chernobyl fallout in this area.  相似文献   

17.
Summary Measurements of phase velocities along several paths in southeastern Europe and along one path in the Eastern Mediterranean have been made in the period range 15 to 60 sec for the fundamental mode of Rayleigh waves. The data are fitted by layered models of the crust and upper mantle. The crust in the Balkan peninsula is thicker than the normal continental crust by about 10 km while the crust in the northern Aegean Sea has the normal continental thickness. The existence of a low shear velocity layer of thickness equal to 140 km with its top in a depth of 90 km interpretes the data well for the longer periods. The data for the eastern Mediterranean show that this region has an oceanic character. The mean crustal thickness in this area is of the order of 20 km.  相似文献   

18.

Earthquake magnitude calibration using hydrophone records has been carried out at Campi Flegrei caldera, an active area close to the highly populated area of Naples city, partly undersea. Definite integrals of the hydrophone records amplitude spectra, between the limits of 1 and 20 Hz, were calculated on a set of small volcano-tectonic earthquakes with moment magnitudes ranging from 1 to 3.3. The coefficients of a linear relationship between the logarithm of these integrals and the magnitude were obtained by linear optimization, thus defining a useful equation to calculate the moment magnitude from the hydrophone record spectra. This method could be easily exported to other volcanic areas, where submerged volcanoes are monitored by networks of hydrophones and seismic sensors on land. The proposed approach allows indeed magnitude measurements of small magnitude earthquakes occurring at sea, thus adding useful information to the seismicity of these volcanoes.

  相似文献   

19.
The common mussel Mytilus galloprovincialis was selected as unique biomonitor species to implement a regional monitoring programme, the CIESM Mediterranean Mussel Watch (MMW), in the Mediterranean and Black Seas. As of today, and upon standardization of the methodological approach, the MMW Network has been able to quantify 137Cs levels in mussels from 60 coastal stations and to produce the first distribution map of this artificial radionuclide at the scale of the entire Mediterranean and Black Seas. While measured 137Cs levels were found to be very low (usually <1 Bq kg−1 wet wt) 137Cs activity concentrations in the Black Sea and North Aegean Sea were up to two orders of magnitude higher than those in the western Mediterranean Basin. Such effects, far from representing a threat to human populations or the environment, reflect a persistent signature of the Chernobyl fallout in this area.  相似文献   

20.
The explosive eruption on the island of Santorini in ∼1630 B.C. in Minoan times had a large environmental impact over the eastern Mediterranean region. It has even been suggested that the Mn-enriched layer (the “Marker Bed”) above the most recent sapropel (S1) in sediments of a crestal area of the Mediterranean Ridge gained Mn from a hydrothermal source related to the Santorini eruption. Radiocarbon dating of two cores from this area sampled at high resolution demonstrate that this large Mn peak in fact pre-dates the Santorini event by ∼2.8 ky and forms part of a pattern seen in Mn profiles from all over the eastern Mediterranean. This same Mn profile shape is altered in areas that experienced substantial deposits of either the tephra layer emitted by the Santorini eruption or the turbidites that were triggered by it. Evidence of both of these perturbations is readily identified from compositional element/Al and Sr/Ca profiles that are distinct from those of the enclosing sediments. In one core with a 37 cm thick Santorini ash layer an oxidation front succeeded in penetrating the whole ash layer after emplacement to form a Mn peak but is now retreating. In cores where thin (< 15 cm) Santorini turbidites or ash layers lie above S1, oxidation fronts initially form additional Mn peaks on top of the turbidites and subsequently alter the characteristic double peaked Mn profile shape usually observed above sapropel S1.  相似文献   

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