Search results for "oceanography"
showing 10 items of 1567 documents
Evaluation of the Potential Energy from Wave Motion on the Sicilian coast
2013
The purpose of this articles is quantitatively evaluate the wave climate variations of the northern Sicilian coasts. In particular, the objective of the study is Castellammare del Golfo, a marine site between Trapani and Palermo. In particular in this research, the wave energy of the Sicily has been studied by an analysis of wave data carried out in a 10- year period, using the measurements of buoyant of RON. The north-western and southern coasts of Sicily have a lower potential with average wave power ranging between 2.5 and 6.5 kW/m.
Piecewise planar underwater mosaicing
2015
A commonly ignored problem in planar mosaics, yet often present in practice, is the selection of a reference homography reprojection frame where to attach the successive image frames of the mosaic. A bad choice for the reference frame can lead to severe distortions in the mosaic and can degenerate in incorrect configurations after some sequential frame concatenations. This problem is accentuated in uncontrolled underwater acquisition setups as those provided by AUVs or ROVs due to both the noisy trajectory of the acquisition vehicle — with roll and pitch shakes — and to the non-flat nature of the seabed which tends to break the planarity assumption implicit in the mosaic construction. These…
The Portuguese Man-of-War Has Always Entered the Mediterranean Sea—Strandings, Sightings, and Museum Collections
2022
A search of records from different kinds of sources namely, scientific and grey literature, social media, and zoological museum collections, has been carried out to review the incidence of Physalia physalis (Linnaeus, 1758), the Portuguese man-of-war, in the Mediterranean Sea. The temporal frame of the records, considered valid if documented with images or collected specimens, ranged from the second half of the eighteenth century to the year 2021. Thanks to colonies preserved in some Italian historical museum collections, originating from the western basin, it was possible to date the putative first documented record of P. physalis of the Mediterranean Sea in 1850. The dataset shows some ma…
Disentangling conditional effects of multiple regime shifts on Atlantic cod productivity
2020
AbstractRegime shifts are increasingly prevalent in the ecological literature. However, definitions vary, and many detection methods are subjective. Here, we employ an operationally objective means of identifying regime shifts, using a Bayesian online change-point detection algorithm able to simultaneously identify shifts in the mean and(or) variance of time series data. We detected multiple regime shifts in long-term (59-154 years) patterns of coastal Norwegian Atlantic cod (>70% decline) and putative drivers of cod productivity: North Atlantic Oscillation (NAO); sea-surface temperature; zooplankton abundance; fishing mortality (F). The consequences of an environmental or climate-relate…
Deep-sea Tardigrada from South Shetland Islands (Antarctica) with description of Angursa antarctica sp. nov. (Arthrotardigrada, Halechiniscidae)
1998
A new species of marine tardigrade is described coming from the muddy sediment of the Antarctic deep sea. Angursa antarctica sp. nov. is characterized by the presence of balloon-shaped primary clavae, long lateral cirri, long cephalic cirri, spines on legs I, hemispherical capsule-shaped papillae on legs IV, and short external peduncles. Geographical distribution of the genus Angursa extends to Antarctic waters, suggesting a cosmopolitan distribution for this bathyal and abyssal genus. A table comparing the main differentiating characteristics of the species of Angursa is presented.
Benthic hydroids from the south of Livingston Island (South Shetland Islands, Antarctica) collected by the Spanish Antarctic expedition Bentart 94
2006
Twenty-five species of benthic hydroids were collected during the Spanish Antarctic expedition Bentart 94 from the south of Livingston Island (Antarctica). All species are considered regarding autecology and geographical distribution. The systematic position amongst allied species is discussed when considered necessary. Antarctoscyphus asymmetricus and Symplectoscyphus nesioticus are reported for the second and the third time, respectively.
Heterogeneous vertical structure of the bacterioplankton community in a non-stratified Antarctic lake
2013
10 páginas, 4 figuras, 2 tablas.
Geomorphological evolution of the River Loukkos estuary around the Phoenician city of Lixus on the Atlantic Littoral of Morocco
2009
The ancient city of Lixus, today situated on a hill on the right bank of the River Loukkos, 4km from the coast, was founded on the shore of a brackish lagoon that was sheltered from Atlantic storms. This geographical context provided the city with one of the best Phoenician harbors and abundant fishing resources, and allowed access to the Gharb cattle farming resources and cereal production systems. In this study, the historical evolution of the Loukkos estuarine environment is reconstructed through geomorphological and sedimentological analyses, combined with cartographic, archaeological, and geographical data. The outcomes reveal the progressive infilling of the estuarine lagoon of Lixus …
Shoreline Evolution and Environmental Changes at the NW Area of the Gulf of Gela (Sicily, Italy)
2021
Coastal areas are among the most biologically productive, dynamic and valued ecosystems on Earth. They are subject to changes that greatly vary in scale, time and duration and to additional pressures resulting from anthropogenic activities. The aim of this work was to investigate the shoreline evolution and the main environmental changes of the coastal stretch between the towns of Licata and Gela (in the Gulf of Gela, Sicily, Italy). The methodology used in this work included the analysis of: (i) shoreline changes over the long- and medium-term periods (1955–2019 and 1989–2019, respectively), (ii) dune system fragmentation and (iii) the impact of coastal structures (harbours and breakwaters…
Coupling a hydro-maritime model and remotely sensed techniques to assess the shoreline positioning uncertainty: the Marsala coast study case
2010
The severe erosion phenomena affecting the Mediterranean coasts are strictly related to geophysical characteristics and socio-economic pressures. This suggests the need of monitoring and modelling the phenomenon in order to quantify its strength. In fact, the shoreline position, as well as its temporal evolution, provides important information for designing defence structures and for the development of a coastal management plan. The shoreline has a dynamic nature as it changes both in the short and long period. Those changes are caused by geo-morphological (e.g. bars and barrier island development etc.) and hydrodynamic (wave motion, tides and flows) processes, as well as by sudden and fast…