Cozzi S.,CNR Marine Science Institute |
Giani M.,National Institute of Oceanography and Applied Geophysics - OGS
Continental Shelf Research | Year: 2011
Runoff and nutrient transport by rivers were analysed in the Northern Adriatic continental shelf, in order to evaluate their interannual and multidecal variability, as well as their current contribution to determine freshwater and nutrient budgets in this marine region. During the years 2004-2007, the runoff in the basin (34.1-64.6km3yr-1) was highly imbalanced, being 84% of freshwater discharged along the western coast, because of the contributions of Po, Adige and Brenta rivers. In the northern and eastern sections of the coast, freshwater discharge by rivers was less important (10 and 6%, respectively), but not negligible in determining the oceanographic properties at sub-regional scales. The oscillations of the transport of biogenic elements (124-262×103tNyr-1 for TN, 72-136×103tNyr-1 for DIN, 4.5-11.1×103tPyr-1 for TP, 2.2-3.5×103tPyr-1 for PO4 and 104-196×103tSiyr-1 for SiO2) were strictly dependant to the differences in the annual runoff. A strong excess of N load in comparison to P load characterised all rivers, both in inorganic nutrient (DIN/PO4=37-418) and total (TN/TP=48-208) pools, particularly in the northern and eastern areas of the basin.The annual runoff showed significant oscillations for Po on multidecadal time scale, whereas a general decrease (-33%) was observed for the other N Adriatic rivers as the recent discharges were compared to those before the 1980s. During the dry years 2005-2007, a strong reduction of river water flows and nutrient loads was experienced by the N Adriatic ecosystem with respect to years characterised by medium-high regimes. An increased frequency of similar drought periods, due to ongoing climate changes or to a larger human usage of continental waters, would be easily able to significantly change the biogeochemistry of this basin. © 2011 Elsevier Ltd.
Taviani M.,CNR Marine Science Institute
Lecture Notes in Earth Sciences | Year: 2011
This paper is focused upon the Miocene-to-Recent deep-sea chemosynthetic ecosystems of the Mediterranean basin with emphasis on their metazoan associates. The life ingredients of this story are basically the "microbes" and the "metazoans", in particular molluscs, whose mutual interplay resulted in a superb variety of situations in response to geologic and oceanographic factors directing the production and availability of geofluids usable by microbial consortia. The astounding complexity and diversity of modern metazoan-bearing deep-sea ecosystems inhabiting the Mediterranean is a step of a long journey whose beginning dates back to more than 3 billion years ago and whose major events are resumed below. © 2011 Springer Berlin Heidelberg.
Pezzutto P.,CNR Marine Science Institute
Coastal Engineering | Year: 2016
Second-order Stokes-like solution of the wavemaker problem involves the participation of first order evanescent modes to the generation of spurious free harmonics. The unwanted free potential, and the paddle signal needed to suppress it, must be evaluated through series summation which, up to now, have been considered non-convergent for certain wavemaker configurations. This paper presents a demonstration of the convergence of these series summation for the historically discarded configurations. Following previous works, the free harmonics second order transfer function can obtained in two different ways. This operation reveals that the two alternative solutions match only if the lateral boundary condition is properly described. In particular, the domain restriction of non-continuous paddle shapes must be represented through left-continuous step functions. Conversely, if the support is limited only adjusting the integration limits, or the unit step function is non-zero at the origin, one of the two methods leads to an incomplete formulation. © 2016
Marini M.,CNR Marine Science Institute |
Frapiccini E.,CNR Marine Science Institute
Chemosphere | Year: 2013
The Po Valley is the most important agricultural and industrial area of Adriatic basin. In this area there are several rivers which transport polycyclic aromatic hydrocarbons (PAHs) into the sea via suspended particulate matter. This study describes the persistence of PAHs in the deep and coastal sediments of the Northern Adriatic. Different environmental conditions were studied: salinity, temperature, sunlight, sediment particle size and organic matter in sediment. The average conditions in the deep areas of the Northern Adriatic are: salinity higher than 37, temperature lower than 11. °C, darkness and clayey sediments with a high organic matter content. These conditions increase the persistence of the PAHs in the deep area of the Northern Adriatic. © 2012 Elsevier Ltd.
Argnani A.,CNR Marine Science Institute
Tectonophysics | Year: 2012
The polarity of subduction in the Corsica-Northern Apennine system is a long-debated issue. Models adopting an original W-dipping subduction and models preferring a flip in the polarity of subduction, from E-dipping to W-dipping present inconsistencies that are mainly due to the 2D approach. A new proposal is presented, using Late Cretaceous to Present-Day kinematic reconstructions of the Central Mediterranean. A wide oceanic embayment is required to the west of the Adriatic Promontory, to account for the Oligocene-Present calcalkaline volcanism and back-arc extension. This implies that the continental collision that originated the Alps s.s. could not continue SW-ward of Adria. The change in subduction polarity, going from the Alps, to the Apennines, is taken as on original feature since the beginning of convergence. Kinematic reconstructions show that the point where subduction polarity changes moved N-ward along the plate boundary, from Late Cretaceous to Eocene. As a result, areas that previously experienced the continental collision of the Adriatic Promontory were subsequently affected by the oceanic subduction of the Tethyan embayment. This sequence of events caused the collapse of Alpine Corsica and led to the opening of the Balearic back-arc basin.A similar kinematic evolution is ongoing in Taiwan, where the N-ward subduction of the Philippine Sea plate is progressively substituting the E-ward subduction of the Eurasian plate, causing the collapse of the orogen in northern Taiwan.The slivers of continental basement rocks that are encased within the uppermost nappe in Corsica have been interpreted as remnants of a microplate that collided with Corsica. Plate kinematics offers an alternative explanation, with these basement rocks being derived from the colliding Adriatic promontory during Paleocene-Eocene; the promontory then passed away laterally, allowing the juxtaposition of the Alpine belt of Corsica with the early Apennines. © 2012 Elsevier B.V.
Corinaldesi C.,Marche Polytechnic University |
Corinaldesi C.,CNR Marine Science Institute
Proceedings. Biological sciences / The Royal Society | Year: 2014
Deep hypersaline anoxic basins (DHABs) of the Mediterranean Sea are among the most extreme ecosystems on Earth and host abundant, active and diversified prokaryotic assemblages. However, factors influencing biodiversity and ecosystem functioning are still largely unknown. We investigated, for the first time, the impact of viruses on the prokaryotic assemblages and dynamics of extracellular DNA pool in the sediments of La Medee, the largest DHAB found on Earth. We also compared, in La Medee and L'Atalante sediments, the diversity of prokaryotic 16S rDNA sequences contained in the extracellular DNA released by virus-induced prokaryotic mortality. We found that DHAB sediments are hot-spots of viral infections, which largely contribute to the release of high amounts of extracellular DNA. DNase activities in DHAB sediments were much higher than other extracellular enzymatic activities, suggesting that extracellular DNA released from killed prokaryotes can be the most suitable trophic resource for benthic prokaryotes. Preserved extracellular DNA pools, which contained novel and diversified gene sequences, were very similar between the DHABs but dissimilar from the respective microbial DNA pools. We conclude that the strong viral impact in DHAB sediments influences the genetic composition of extracellular DNA, which can preserve the signatures of present and past infections.
Argnani A.,CNR Marine Science Institute
Italian Journal of Geosciences | Year: 2013
The front of the W-verging Albanide fold-and-thrust belt and its adjacent foreland have been investigated using a grid of seismic reflection profiles, purposely acquired in the Southern Adriatic Sea. This convergent margin is part of the continental collision that extends from former Yugoslavia to North-Western Greece. At the front of the Albanides, both the structural style of the external part of the fold-and-thrust belt, and the evolution of the related foredeep basin, are strongly controlled by the nature of the Mesozoic units that are progressively accreted to the belt, namely the Apulian Platform and its adjacent deep-water basins. Where a thick carbonate platform is accreted (souther Albania) the frontal mountain range presents a high topography, whereas the foredeep basin is relatively shallow. On the other hand, where the basinal domain is accreted (northern Albania), the topography of the fold-and-thrust belt is subdue, whereas the foredeep basin is very deep. © Società Geologica Italiana, Roma 2013.
Maselli V.,CNR Marine Science Institute |
Trincardi F.,CNR Marine Science Institute
Global and Planetary Change | Year: 2013
The Manfredonia Incised Valley (MIV) is a huge erosional feature buried below the Apulian shelf, on the western side of the Adriatic margin. The incision extends more than 60. km eastward, from the Tavoliere Plain to the outer shelf, not reaching the shelf edge. High-resolution chirp sonar profiles allow reconstruction of the morphology of the incision and its correlation at regional scale. The MIV records a single episode of incision, induced by the last glacial-interglacial sea level fall that forced the rivers draining the Tavoliere Plain to advance basinward, reaching their maximum extent at the peak of the Last Glacial Maximum. The valley was filled during a relatively short interval of about 10,000. yr during the Late Pleistocene-Holocene sea level rise and almost leveled-off at the time of maximum marine ingression, possibly recording the short-term climatic fluctuations that occurred. The accommodation space generated by the lowstand incision was exploited during the following interval of sea level rise by very high rates of sediment supply that allowed the preservation of up to 45. m of valley fill. High-resolution chirp sonar profiles highlight stratal geometries that are consistent with a typical transgressive valley fill of an estuary environment, including bay-head deltas, central basin and distal barrier-island deposits, organized in a backstepping configuration. The highest complexity of the valley fill is reached in the shallowest and most proximal area, where a kilometric prograding wedge formed during a period dominated by riverine input, possibly connected to high precipitation rates. Based on the depth of the valley margins during this interval, the fill was likely isochronous with the formation of sapropel S1 in the Mediterranean region and may have recorded significant fluctuations within the hydrological cycle. © 2012 Elsevier B.V..
La Mesa M.,CNR Marine Science Institute |
Eastman J.T.,Ohio University
Fish and Fisheries | Year: 2012
Among the endemic notothenioid fish of Antarctica, the Antarctic silverfish (Pleuragramma antarcticum) is the only species in which all developmental stages live throughout the water column. It is widely distributed in the shelf waters around the continent, inhabiting both open waters and areas of pack ice at depths from 0 to 900m. In successfully occupying this habitat, it evolved a suite of specific biological, ecological and physiological adaptations to the environmental conditions in the cold and highly seasonal Antarctic waters. Specialization for the pelagic environment evolved over millions of years enabled life under unusual environmental constraints and colonization of the pelagic realm of the Antarctic continental shelf. A sudden change of environmental conditions driven by the current rapid climate change could negatively affect this weak equilibrium, with a catastrophic cascade effecting higher trophic levels. Indeed, as both adults and early life stages of the Antarctic silverfish appear to be strongly dependent on sea-ice, this species would be especially sensitive to climatic or oceanic changes that reduce the extent of sea-ice cover or the timing of formation of coastal polynyas. © 2011 Blackwell Publishing Ltd.
Raicich F.,CNR Marine Science Institute
Continental Shelf Research | Year: 2010
Daily sea level variability in the Adriatic Sea is studied from different data sets using Empirical Orthogonal Functions, in connection with atmospheric pressure and wind stress. The first mode explains 56-69% of total variance and consists of uniform sea level variability all over the basin, correlated with atmospheric pressure through the inverse barometer effect. The second mode explains 13-16% of variance and accounts for an along-basin sea level gradient, which is correlated with the meridional wind stress component. The first two Principal Components are used as proxies to pressure- and wind-induced components of storm surges in the northern Adriatic. The analysis of the frequency of the most intense events in the 1957-2005 period shows that the wind contribution to storm surges has decreased, while no significant trends are found in the contribution of atmospheric pressure. © 2010 Elsevier Ltd.