This model is based on the concept of transport concentration, defined as the time-averaged concentration in a given location of a lagoon, which determines the long-term net transport of sediments as ...the sum of a dispersive and an advective flux. Dispersive net flux of sediments is due to the alternate components of the tidal flow, while the advective net flux of sediments is due to the residual (Eulerian) component of the tidal, fluvial and littoral flow and possibly to the asymmetry between flow and ebb tide.
The long-term deposition (or erosion) rate in a given location is expressed as proportional to the difference between the local transport concentration and the local equilibrium concentration, depending in turn on the local stirring action by waves and currents.
The two-dimensional model is able to reproduce the ontogeny of a tidal lagoon as a consequence of a breaching of the littoral dune line. During the ontogenetic phase, the system tends rapidly toward a quasi-equilibrium condition apparently characterized by a stable planimetric configuration of the channel network. The structure of the channels and their watersheds is qualitatively similar to the Venice Lagoon's ones. After the relatively fast ontogenetic phase, the subsequent morphological evolution of the bottom continues at a slower pace until a stable bathymetric configuration of the lagoon is reached. The model is able to reproduce the morphological effects of subsequent perturbations of natural or anthropogenic origin.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Ectopleura crocea is an Anthomedusan hydroid, frequently recorded and abundant on artificial substrates. Here we examine whether the abundance of this species varies seasonally on a shipwreck in the ...Northern Adriatic at a depth of 10–12 m. Individuals were first found in late autumn when temperatures had dropped below 15 °C, forming scattered colonies composed of a few, small hydranths bearing immature gonophores. Substratum cover and density increased throughout late winter and spring, reaching a peak in April. At temperatures of about 19 °C, colonies were no longer present in June and remained absent throughout the summer. The polyp gut contents comprised mostly crustaceans.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Background The presence of species belonging to genus Paramphitrite (Terebellidae) has been recorded in the Temperate Northern Atlantic and Arctic regions (Iberian Atlantic, Norwegian and Russian ...seas). This paper describes the first occurrence of Paramphitrite birulai (Ssolowiew, 1899) in the Mediterranean Sea. Methods Sampling surveys were carried out in the North Adriatic Sea about 30 nm offshore Chioggia (Italy) on soft seabed at depths ranging from 29 to 32 meters. The sampling plan provided 18 stations. Results Seventy-four Paramphitrite birulai specimens were examined from a morphological point of view and described in comparison with the existing literature. The species was collected in sandy sediments. Conclusions The record of P. birulai in the North Adriatic Sea represents the first report of the genus Paramphitrite in the Mediterranean Sea extending the distribution range of this species into different ecological and environmental conditions if compared with those where it was previously recorded.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
► A novel survey of 129I levels in the marine environment of the North Adriatic. ► 129I accumulates in marine sediment, the Mediterranean mussel Mytilus galloprovincialis and the alga Fucus ...virsoides. ► The content of 129I in the sea water of the North Adriatic. ► To follow 129I trends, pathways and cycling of the Adriatic and the Mediterranean.
Compared to the pre-nuclear era, large amounts of 129I have been released to the marine environment, especially as liquid and gaseous discharges from two European reprocessing plants located at Sellafield and La Hague. Their liquid discharges influence Northern Europe and most research was conducted in the area of the North Atlantic Ocean and the Baltic Sea. In this article data on 129I content and 129I/127I ratios observed in the North Adriatic Sea, which is a rather enclosed basin of the Mediterranean Sea, are presented. To the best of our knowledge no data on 129I in the Mediterranean Sea have previously been reported. As this area is isolated from direct liquid discharges, the main transport pathway is probably gaseous releases from reprocessing plants. Surface sea water, the marine alga Fucus virsoides, an iodine accumulator, and the Mediterranean mussel Mytilus galloprovincialis collected in 2009 and 2010, and marine sediment collected in 2005 and 2009 were analysed. The 129I/127I isotopic ratios observed were in the range from 0.8 to 3.0×10−08 for seawater, from 0.06 to 0.35×10−08 for marine sediment, from 0.05 to 0.10×10−08 for F. virsoides and from 0.3 to 0.9×10−08 for M. galloprovincialis.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Current global trends will lead to large-scale changes in climate patterns, ocean circulation and stratification; increased atmospheric CO
2
levels will cause acidification of the oceans, with ...significant impacts on marine biogeochemical cycles and calcareous organisms. In the Mediterranean area, the northern Adriatic Sea is one of the most suitable sites for studying the responses of marine pH to such occurrences because it is the northernmost basin affected by dense water formation during winter, and is also one of the most productive areas in the Mediterranean. The first comparison between two sets of data relating to the dense cold waters of the northern Adriatic, formed in the winters of 1982-1983 and 2007-2008, is presented here. pH values on the Nation Bureau Standard scale from the old dataset have been converted to the 'total hydrogen ion concentration scale' adopted for the new dataset, and are expressed as μmol H
. Results at 25 °C show acidification (−0.063 pH
T
units) and a decrease in carbonate ion concentration (−19.6 μmol H
) in the dense water mass between 1983 and 2008, whereas total alkalinity, carbonate alkalinity, dissolved inorganic carbon and CO
2
fugacity exhibit net increases of 74.4, 77.8 and 110.3 μmol H
, and 108.3 μatm, respectively, over the same period.
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BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Beach nourishment (i.e. the addition of sediments transported from other source locations) is increasingly used to counteract erosion of coastal areas. We tested whether sediment descriptors (grain ...size structure and organic content) and macrobenthic assemblages (species composition and abundance) differed among replicated shores previously exposed to nourishment alone (N), nourishment in combination with pre-existing hard structures (N
+
H) or no nourishment (NoN) along about 50
km of shores of the Emilia Romagna region (North Adriatic Sea, Italy). There was large variation among shores. Two out of three N shores were nearly defaunated, while one N shore had species composition and abundances comparable to NoN shores. There were also large differences between N and N
+
H shores, the latter possessing higher abundances of organisms and the presence of species that do not usually occur in the nearshore surf habitats in this region. More than 50% of the variability in the benthic assemblages was related to variations in the grain size structure of the sediments among shores. The results suggest that beach nourishments may lead to modifications of sedimentary environments and inhabiting fauna, but the resulting effects may be strongly related to local conditions, which dictate the rate at which added sand is redistributed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The distributions of sterols and organic-walled dinoflagellate cysts (dinocysts) in five NW Adriatic Sea surface sediment samples were investigated. Samples are representative of areas differently ...influenced by freshwater inputs, mainly coming from the Po River. All the investigated samples exhibit the same suite of principal sterols, with cholest-5-en-3β-ol (cholesterol), 4α,23,24-trimethyl-5α-cholest-22
E-en-3β-ol (dinosterol), 24-ethylcholest-5-en-3β-ol (sitosterol) and 24-methylcholesta-5,22
E-dien-3β-ol (brassicasterol or epibrassicasterol) displaying the highest concentrations and relative abundances. The distribution of sterols in the samples is not related to their distance from the coast and/or with the C/N ratios and suggests a prevalent input of marine, autochthonous organic matter in the surface sediments. In particular, the high abundance of dinosterol underlines the importance of dinoflagellate productivity in this area and its contribution to the organic matter in sediments. However, absolute and relative abundances of dinosterol do not follow the trend observed for dinocyst concentrations in the investigated samples, with the exception of
Spiniferites spp. cysts and cysts produced by
Gonyaulax species.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Characterization of surface-active organic substances in the North Adriatic Sea, in surface and bottom layers, during the year 2000 has been performed. Surface-active substances (SAS), their ...hydrophobicity and acidity, were estimated with alternating current voltammetry (in-phase mode) using
o-nitrophenol as an electrochemical probe. Depending on hydrophobicity and acidity of SAS present, the electrochemical characteristics of the
o-nitrophenol probe change in a specific way. Normalization of the change of prepeak height as an indication of organic matter acidity to shift of peak potential as a measure of hydrophobicity gives an indication of relative acidity of the SAS present. Experiments with model substances showed that humic and fulvic acids contribute the most to the relative acidity, while biogenic surface-active organic substances such as proteins, polysaccharides and lipids contribute less to the relative acidity.
The surface water layer is characterized by higher phytoplankton excretion during the whole year, resulting in a higher contribution of freshly produced biogenic organic substances to the surfactant activity (SA). Humic and fulvic substances dominate in SA in the bottom layer. Proteinaceous material is found in a heterodispersed fraction during supposed phytoplankton blooms that occurred in March, July, September and even December, in the northern Adriatic, in connection with unexpectedly high temperatures. SA of the particulate fraction was found to be mainly less than 10%. Exceptions were obtained in April and October when SA of the particulate fraction contributed up to 55 and 20%, respectively.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A seasonal study of the quantitative and qualitative distribution of heterotrophic bacterial community was carried out in the Adriatic Sea between April 1995 and January 1996, in order to evaluate ...its spatial and temporal variability and metabolic potential in the degradation processes of organic matter.
The culturable bacteria (CFU) ranged between 0.1 and 22% of total bacterioplankton with a maximum percentage in surface samples of coastal zones. Their distribution was generally affected by the prevailing hydrological conditions. At the coastal stations about 44–75% of CFU variance could be explained by river runoff. The changes in the composition of heterotrophic bacterial community showed a seasonal succession of main bacterial groups, with a prevalence of Gram negative, non fermenting bacteria in the cold period (April–January) and an increase of
Vibrionaceae and pigmented bacteria in summer. The seasonal variations were more important at the stations influenced by rivers than offshore. The bacterial community showed a greater versatility for organic polymers hydrolysis in the offshore station than in the coastal areas. Over 60% of all isolated heterotrophic bacteria expressed peptidase, lipase and phosphatase ectoenzymes activities, in all seasons and showed an increasing trend in warm period (in July–October). The α- and β-glucosidase potentials of bacteria were lower (20% on average) and showed different pattern during the year. These results suggest different role of the bacterial community in the decomposition of organic matter in the Adriatic Sea. Since only 20% of bacterial strains expressed glucosidase activity, carbohydrate-rich polymers such as mucilage might accumulate.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Net-zooplankton data collected monthly at one coastal station of the Gulf of Trieste (Northern Adriatic Sea) from 1970 to 1980 were analysed in order to test the existence of any successional trend ...among the copepod community. No periodicity was evident for single species. However, a clear periodicity was found for two species groups obtained by cluster analysis. One group was characterized by Acartia clausi and Temora longicornis and showed a regular appearance in late spring–summer. The other group was characterized by Temora stylifera and Oncaea sp. and showed a regular appearance in autumn–winter. Time-series analysis of the diversity of the copepod community showed a clear 12-month periodicity with winter maxima corresponding to the highest level of stability. However, a decreasing trend of the copepod biomass appears to have originated in the mid-1970s. The biomass decrease was probably caused by Noctiluca miliaris and Pelagia noctiluca blooms.
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