scholarly journals Vortices of the Mediterranean Sea: An Altimetric Perspective

2006 ◽  
Vol 36 (1) ◽  
pp. 87-103 ◽  
Author(s):  
Jordi Isern-Fontanet ◽  
Emilio García-Ladona ◽  
Jordi Font

Abstract The presence of coherent vortices makes observed mesoscale fields of the ocean resemble two-dimensional turbulence. Using this analogy, a common definition of a coherent structure has been used to study the statistical properties of Mediterranean Sea vortices observed by satellite altimeters over a 7-yr period. A vortex has been defined as the simply connected region with values of the Okubo–Weiss parameter W < −0.2σW, where σW is the spatial standard deviation of W, and the same sign of vorticity. This definition is shown to be appropriate to detect and characterize, statistically, properties such as size, mean kinetic energy, and amplitude of vortices in the Mediterranean basin from sea level anomaly maps corresponding to the period from October 1992 to October 1999. The distribution of such properties for the Mediterranean vortices suggests a heuristic criterion to extract and select very coherent and long-lived vortices from the whole set of structures identified in altimetric maps. Such coherent vortices appear to be selected for amplitudes greater than 2σW, where the amplitude has been defined in terms of the Okubo–Weiss parameter rather than vorticity, and strongly correspond to those reported from observations with independent data. Systematic locating and tracking of such vortices provide, for the first time, a general picture of their preferential paths in the Mediterranean basin, which are characterized by complex but rather well defined patterns.

Author(s):  
Joshua M. White

This book offers a comprehensive examination of the shape and impact of piracy in the eastern half of the Mediterranean and the Ottoman Empire’s administrative, legal, and diplomatic response. In the late sixteenth and seventeenth centuries, piracy had a tremendous effect on the formation of international law, the conduct of diplomacy, the articulation of Ottoman imperial and Islamic law, and their application in Ottoman courts. Piracy and Law draws on research in archives and libraries in Istanbul, Venice, Crete, London, and Paris to bring the Ottoman state and Ottoman victims into the story for the first time. It explains why piracy exploded after the 1570s and why the Ottoman state was largely unable to marshal an effective military solution even as it responded dynamically in the spheres of law and diplomacy. By focusing on the Ottoman victims, jurists, and officials who had to contend most with the consequences of piracy, Piracy and Law reveals a broader range of piratical practitioners than the Muslim and Catholic corsairs who have typically been the focus of study and considers their consequences for the Ottoman state and those who traveled through Ottoman waters. This book argues that what made the eastern half of the Mediterranean basin the Ottoman Mediterranean, more than sovereignty or naval supremacy—which was ephemeral—was that it was a legal space. The challenge of piracy helped to define its contours.


2021 ◽  
Author(s):  
Valeria Vaccher ◽  
Stefano Furlani ◽  
Sara Biolchi ◽  
Chiara Boccali ◽  
Alice Busetti ◽  
...  

<p>The Mediterranean basin displays a variety of neotectonics scenarios leading to positive or negative vertical displacement, which change the vertical position of former coastlines. As a result, the best locations to evaluate former sea levels and validate sea-level models are tectonically stable areas. There are a number of coastal areas considered to be stable based on the elevation of paleo sea-level markers, the absence of historical seismicity, and by their position far from major Mediterranean faults. We report here the results of swim surveys carried out at such locations following the Geoswim approach described by Furlani (2020) in nine coastal sectors of the central Mediterranean Sea (Egadi Island - Marettimo, Favignana, Levanzo, Gaeta Promontory, Circeo Promontory, North Sardinia - Razzoli, Budelli, Santa Maria, NW Sardinia – Capocaccia, Maddalena Archipelago, Tavolara Island, East of Malta - Ahrax Point, Bugibba-Qawra, Delimara, Addura, Palermo, Ansedonia Promontory). All the sites are considered to be tectonically stable, as validated by the elevation of sea-level indicators. In fact, modern and MIS5.5 (last interglacial) m.s.l. altitudes fit well with accepted figures based upon field data and model projections. Starting from precise morphometric parameters such as the size of tidal notches and indicative landforms and biological structures, we have developed a procedure that integrates multiple geomorphological and biological descriptors applicable to the vast spectrum of locally diverse coastal situations occurring in the Mediterranean Sea. We took detailed measurements of features such as modern and MIS5.5 tidal notches at 146 sites in all the areas, the absence of modern tidal notch at Circeo promontory, shore platforms, and MIS5.5 marine terraces at Egadi islands, Malta, and Palermo. Biological structures were also measured. In particular, vermetid platforms at Egadi, Palermo and Malta. The morphometric characteristics of these indicators depend on 1) local geological and structural constraints, 2) local geomorphotypes, 3) climate, sea, and weather conditions that affect geomorphic and biological processes, and 4) the sea level change history.</p>


2016 ◽  
Vol 48 (2) ◽  
pp. 125 ◽  
Author(s):  
Marco A. Bologna

<em>Sitarobrachys</em> <em>thoracica</em>, belonging to a monotypic Mediterranean-Macaronesian genus of Meloidae Nemognathinae, is recorded for the first time from southern Turkey. The genus results widely distributed around the Mediterranean Basin and in the eastern Canary Islands.


2019 ◽  
Vol 6 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Giovanni Pasini ◽  
Alessandro Garassino ◽  
Marco Sami

An assemblage of axiidean and brachyuran decapods is reported from the late Miocene pre-evaporitic (early-middle Messinian) limestone of Cò di Sasso, nearby Brisighella (Ravenna, Emilia- Romagna), located in Romagna Apennines (NE Italy). Except Monodaeus bortolottii Delle Cave, 1988 (Xanthidae MacLeay, 1838), which is reported here for the first time in Miocene, all the other specimens have been assigned to species previously known in the Italian Miocene (Messinian s.l.), but never reported in this area. The report of Galathea cf. G. weinfurteri Bachmayer, 1950 (Galatheidae Samouelle, 1819) and Medorippe ampla Garassino, De Angeli, Gallo and Pasini, 2004 (Dorippidae MacLeay, 1838) enlarges the stratigraphic range of these Miocene species. This report enlarges our limited knowledge on the composition and distribution of the axiidean, anomuran, and brachyuran decapods during the early-middle Messinian before the evaporitic event in the Mediterranean Basin.


Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2196 ◽  
Author(s):  
Vinet ◽  
Bigot ◽  
Petrucci ◽  
Papagiannaki ◽  
Llasat ◽  
...  

Recent events in Western Attica in Greece (24 deaths in November 2017), in the Balearic Islands (13 deaths in October 2018), and in southern France (15 deaths in October 2018) show that flood-related mortality remains a major concern in Mediterranean countries facing flash floods. Over the past several years, many initiatives have arisen to create databases on flood-related mortality. An international initiative started in 2011 pooling regional and national databases on flood mortality from region and/or countries bordering the Mediterranean Sea. The MEditerranean Flood Fatality Database (MEFF DB) brings together, in 2018, six Mediterranean regions/countries: Catalonia (Spain), Balearic Islands (Spain), Southern France, Calabria (Italy), Greece, and Turkey, and covers the period 1980–2018. MEFF DB is on progress and, every year, new data are included, but for this study, we kept only the preliminary data that were geolocated and validated on 31st of December 2018. This research introduces a new step in the analysis of flood-related mortality and follows the statistical description of the MEFF DB already published. The goals of this paper are to draw the spatial distribution of flood mortality through a geographical information system (GIS) at different spatial scales: country, NUTS 3 (Nomenclature of Territorial Units for Statistics. Level 3) regions, catchment areas, and grid. A fatality rate (F: number of deaths/year/million of inhabitants) is created to help this analysis. Then, we try to relate mortality to basic (human or physical) drivers such as population density, rainfall seasonality, or rainfall frequency across the Mediterranean Basin. The mapping of F shows a negative mortality gradient between the western and the eastern parts of the Mediterranean Sea. The south of France appears to be the most affected region. The maps also highlight the seasonality of flood-related deaths with the same west–east gradient. It confirms that flood mortality follows the climatological seasonal patterns across the Mediterranean Basin. Flood-related fatalities mainly occur during the early fall season in the western part of the Mediterranean area, while the Easter Basin is affected later, in November or during the winter season. Eastern Turkey introduces another pattern, as mortality is more severe in summer. Mortality maps are then compared with factors that potentially contribute to the occurrence of flood fatalities, such as precipitation intensity (rainfall hazard), to explain geographical differences in the fatality rate. The density of a fatal event is correlated to the population density and the rainfall frequency. Conversely, the average number of deaths per event depends on other factors such as prevention or crisis management.


2009 ◽  
Vol 6 (4) ◽  
pp. 647-662 ◽  
Author(s):  
I. E. Huertas ◽  
A. F. Ríos ◽  
J. García-Lafuente ◽  
A. Makaoui ◽  
S. Rodríguez-Gálvez ◽  
...  

Abstract. The exchange of both anthropogenic and natural inorganic carbon between the Atlantic Ocean and the Mediterranean Sea through Strait of Gibraltar was studied for a period of two years under the frame of the CARBOOCEAN project. A comprehensive sampling program was conducted, which was design to collect samples at eight fixed stations located in the Strait in successive cruises periodically distributed through the year in order to ensure a good spatial and temporal coverage. As a result of this monitoring, a time series namely GIFT (GIbraltar Fixed Time series) has been established, allowing the generation of an extensive data set of the carbon system parameters in the area. Data acquired during the development of nine campaigns were analyzed in this work. Total inorganic carbon concentration (CT) was calculated from alkalinity-pHT pairs and appropriate thermodynamic relationships, with the concentration of anthropogenic carbon (CANT) being also computed using two methods, the ΔC* and the TrOCA approach. Applying a two-layer model of water mass exchange through the Strait and using a value of −0.85 Sv for the average transport of the outflowing Mediterranean water recorded in situ during the considered period, a net export of inorganic carbon from the Mediterranean Sea to the Atlantic was obtained, which amounted to 25±0.6 Tg C yr−1. A net alkalinity output of 16±0.6 Tg C yr−1 was also observed to occur through the Strait. In contrast, the Atlantic water was found to contain a higher concentration of anthropogenic carbon than the Mediterranean water, resulting in a net flux of CANT towards the Mediterranean basin of 4.20±0.04 Tg C yr−1 by using the ΔC* method, which constituted the most adequate approach for this environment. A carbon balance in the Mediterranean was assessed and fluxes through the Strait are discussed in relation to the highly diverse estimates available in the literature for the area and the different approaches considered for CANT estimation. This work unequivocally confirms the relevant role of the Strait of Gibraltar as a controlling point for the biogeochemical exchanges occurring between the Mediterranean Sea and the Atlantic Ocean and emphasizes the influence of the Mediterranean basin in the carbon inventories of the North Atlantic.


2020 ◽  
Author(s):  
Roberto Sabia ◽  
Estrella Olmedo ◽  
Giampiero Cossarini ◽  
Aida Alvera-Azcárate ◽  
Veronica Gonzalez-Gambau ◽  
...  

&lt;p&gt;ESA SMOS satellite [1] has been providing first-ever Sea Surface Salinity (SSS) measurements from space for over a decade now. Until recently, inherent algorithm limitations or external interferences hampered a reliable provision of satellite SSS data in semi-enclosed basin such as the Mediterranean Sea. This has been however overcome through different strategies in the retrieval scheme and data filtering approach [2, 3]. This recent capability has been in turn used to infer the spatial and temporal distribution of Total Alkalinity (TA - a crucial parameter of the marine carbonate system) in the Mediterranean, exploiting basin-specific direct relationships existing between salinity and TA.&lt;/p&gt;&lt;p&gt;Preliminary results [4] focused on the differences existing in several parameterizations [e.g, 5] relating these two variables, and how they vary over a seasonal to interannual timescale.&lt;/p&gt;&lt;p&gt;Currently, to verify the consistency and accuracy of the derived products, these data are being validated against a proper ensemble of in-situ, climatology and model outputs within the Mediterranean basin. An error propagation exercise is also being planned to assess how uncertainties in the satellite data would translate into the final products accuracy.&lt;/p&gt;&lt;p&gt;The resulting preliminary estimates of Alkalinity in the Mediterranean Sea will be linked to the overall carbonate system in the broader context of Ocean Acidification assessment and marine carbon cycle.&lt;/p&gt;&lt;p&gt;References:&lt;/p&gt;&lt;p&gt;[1] J. Font et al., &quot;SMOS: The Challenging Sea Surface Salinity Measurement From Space,&quot; in Proceedings of the IEEE, vol. 98, no. 5, pp. 649-665, May 2010. doi: 10.1109/JPROC.2009.2033096&lt;/p&gt;&lt;p&gt;[2] Olmedo, E., J. Martinez, A. Turiel, J. Ballabrera-Poy, and M. Portabella,&amp;#160; &amp;#8220;Debiased non-Bayesian retrieval: A novel approach to SMOS Sea Surface Salinity&amp;#8221;. Remote Sensing of Environment 193, 103-126 (2017).&lt;/p&gt;&lt;p&gt;[3] Alvera-Azc&amp;#225;rate, A., A. Barth, G. Parard, J.-M. Beckers, Analysis of SMOS sea surface salinity data using DINEOF, In Remote Sensing of Environment, Volume 180, 2016, Pages 137-145, ISSN 0034-4257, https://doi.org/10.1016/j.rse.2016.02.044.&lt;/p&gt;&lt;p&gt;[4] Sabia, R., E. Olmedo, G. Cossarini, A. Turiel, A. Alvera-Azc&amp;#225;rate, J. Martinez, D. Fern&amp;#225;ndez-Prieto, Satellite-driven preliminary estimates of Total Alkalinity in the Mediterranean basin, Geophysical Research Abstracts, Vol. 21, EGU2019-17605, EGU General Assembly 2019, Vienna, Austria, April 7-12, 2019.&lt;/p&gt;&lt;p&gt;[5] Cossarini, G., Lazzari, P., and Solidoro, C.: Spatiotemporal variability of alkalinity in the Mediterranean Sea, Biogeosciences, 12, 1647-1658, https://doi.org/10.5194/bg-12-1647-2015, 2015.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;


Author(s):  
Daria Sanna ◽  
Paolo Merella ◽  
Tiziana Lai ◽  
Sarra Farjallah ◽  
Paolo Francalacci ◽  
...  

The bluespotted cornetfish (Fistularia commersonii) is an Indo-Pacific species that in the last ten years colonized a large part of the Mediterranean basin. The aim of this study was to sequence some portions of the mitochondrial DNA (D-loop II, 16S, 12S and Cyt b) of this fish from different localities of the Mediterranean Sea, in order to evaluate the level of its genetic variability in this area. The genetic analysis performed on specimens from seven localities of Sardinia, Tunisia and Libya revealed the presence of at least five mitochondrial lineages. The results obtained, compared with previous studies, indicate that the use of a sufficient number of mitochondrial regions may allow a more accurate estimate of genetic variability in lessepsian invasions.


2009 ◽  
Vol 10 (2) ◽  
pp. 63 ◽  
Author(s):  
C. MIFSUD ◽  
M. TAVIANI ◽  
S. STOHR

The MARCOS cruise, which took place in the South Central Mediterranean Sea on board the RV ‘Urania’, resulted in the collection of 27 species of Echinodermata from shallow to bathyal depths, many from around Malta (the Fisheries Management Zone). The fauna is represented by common to rare taxa already reported from the Mediterranean with the exception of the amphi-Atlantic ophiuroid Ophiotreta valenciennesi rufescens (Koehler, 1896), recorded from the Mediterranean Basin for the first time. Odontaster mediterraneus (von Marenzeller, 1893) and Luidia sarsi Lutken, 1858 are also first records for the Maltese Islands.


2021 ◽  
Author(s):  
Marc Diego-Feliu ◽  
Valentí Rodellas ◽  
Aaron Alorda-Kleinglass ◽  
Júlia Domínguez-Gabarró ◽  
Maarten Saaltink ◽  
...  

&lt;div&gt;&lt;span&gt;Fluxes of nutrients, metals, contaminants, among others dissolved compounds transported from land to oceans have a direct impact on coastal biogeochemical cycles. One of these land-ocean interaction mechanisms, recently recognized as an important source of these compounds, is the flow of groundwater from continental margins to the coastal ocean, commonly known as Submarine Groundwater Discharge (SGD). The Mediterranean coastline is characterized by the presence of ephemeral streams, geomorphological settings that act as preferential flow paths for both runoff and groundwater towards the sea. The Mediterranean Basin is highly influenced by strong precipitation events (&gt;50 mm) that commonly occur during fall and spring seasons such as isolated depression at high levels events, locally named &amp;#8216;gota-freda&amp;#8217;. In such situations, runoff causes several social and environmental impacts along ephemeral streams that have been long recognized. However, when the surface water flow ceases, the subterranean part of ephemeral streams may continue supplying water and solutes to the coastal ocean via SGD. This process and its effects for coastal ecosystems have been largely overlooked. In this study, we evaluated the influence of a &amp;#8216;gota-freda&amp;#8217; event on both the role of ephemeral streams as preferential areas for groundwater discharge and on the magnitude of SGD and SGD-derived nutrient fluxes. To do so, three seawater sampling campaigns were performed in a Mediterranean coastal region dominated by ephemeral streams (Maresme, Catalunya) after heavy rainfall events (~50 mm) and in baseflow conditions. Results of this study indicate that SGD flows are between 5 and 7 times higher after a strong precipitation event than in baseflow conditions indicating that the supply of nutrients and other dissolved compounds to the Mediterranean Sea is highly dependent on these events. This study highlights that this mechanism is a relevant process for coastal biogeochemical cycles of semi-arid regions such as the Mediterranean basin. &lt;/span&gt;&lt;/div&gt;


Sign in / Sign up

Export Citation Format

Share Document