Search results for "Mediterranean Sea."
showing 10 items of 830 documents
Effects of structural complexity on epifaunal assemblages associated with two intertidal Mediterranean seaweeds
2023
Brown foundation seaweeds are key elements increasing substrate heterogeneity and shaping the biodiversity in rocky coastal ecosystems. They are, however, vulnerable species that are declining due to multiple anthropogenic and climate change stressors, leading to a shift to less structural complex habitats. We investigate the role of structural attributes of two intertidal macroalgae, Ericaria amentacea and Laurencia obtusa, in shaping the abundance and diversity of their associated epifaunal assemblages. For this aim, we measured seaweeds’ biomass, thallus volume and length (used here as proxy of substrate complexity), and explored which seaweeds’ substrate attribute explained better varia…
The trophic structure of a pipefish community (Pisces: Syngnathidae) from a western Mediterranean seagrass meadow based on stable isotope analysis
2004
Syngnathus abaster and S. typhle (Pisces. Syngnathidae) from a dense Cymodocea nodosa meadow in the western Mediterranean Stagnone di Marsala (Italy) were studied using δ13C and δ15N analysis. Because of the presence of these two species in the same habitat and the specialized parental care by the male, the effect of species and sex on the isotopic composition was also studied to investigate the different feeding strategies between and within species. S. abaster and S. typhle exhibited enriched 13C and 15N values throughout the sampling period (δ13C mean ± s.e. = -10.5 ± 1.8‰ and -10.8 ± 2.0‰, δ15N mean ± s.e. = 11.9 ± 0.7‰ and 10.6 ± 1.0‰ respectively), suggesting that these species receiv…
Unmanned aerial vehicle technology to assess the state of threatened biogenic formations: The vermetid reefs of mediterranean intertidal rocky coasts
2021
Abstract Vermetid bioconstructions are biogenic formations, built by sessile gastropod molluscs belonging to the family Vermetidae worldwide distributed, occurring in the intertidal and upper subtidal in the rocky shores. In the Mediterranean basin, they occur in complex and tridimensional structures that enhance the local biodiversity, allowing to qualify the structuring species as ecosystem engineers. Due to their ecological relevance and considerable extension along the coasts, we assessed their structural complexity using unmanned aerial vehicle (UAV) technology, as tool of littoral cartography analysis of these bioconstructions, and plaster hemispheres dissolution as a descriptor index…
Crushing predation of the spiny star Marthasterias glacialis upon the sea urchin Paracentrotus lividus
2009
Literature data report that only fish predators are able to crush sea urchin tests in Mediterranean rocky reefs. This experimental study showed that the spiny star Marthasterias glacialis is able to break Paracentrotus lividus tests and that the breaking event is more likely to occur for small-sized sea urchins than for big ones. Our results show that the role of M. glacialis in regulating P. lividus population density can be important in specific locations. They may have important implications, moreover, for the use of tethering techniques aimed at identifying predator types of sea urchins.
Impact of Heavy Metals in Eggs and Tissues of C. caretta along the Sicilian Coast (Mediterranean Sea)
2022
In this study we compared the heavy metal concentration found in different tissues and eggs of the loggerhead sea turtle and evaluated the potential ecotoxicological risk for this important species. Eighteen heavy metal elements were determined in different tissues (liver, gonads, fat, kidney, heart, brain, and spleen) of nine individuals of Caretta caretta found stranded along the coasts of Messina (Sicily, Italy) and in the shell and yolk of six eggs from the island of Linosa (Sicily, Italy). For the analysis of the heavy metals, we used the analytical procedures in accordance with the EPA 200.8 method supplemented by EPA 6020b with three replicates for each measurement. The elements anal…
Searching for the competitive ability of the alien seagrass Halophila stipulacea with the autochthonous species Cymodocea nodosa
2023
The tropical seagrass Halophila stipulacea (Forsskål) Ascherson, 1867 entered in the Mediterranean Sea through the Suez Canal more than 100 years ago. In coastal-marine ecosystems the spatial niche of H. stipulacea is often overlapped with that of native Mediterranean Sea seagrasses and therefore it might out-compete them. Aiming to better understand its invasiveness potential, we monitored a Southern Mediterranean shallow coastal-marine water habitat from August 2010 to August 2011, where H. stipulacea co-occurred with the native seagrass Cymodocea nodosa (Ucria) Ascherson, 1870. Besides, the year-round dynamics of H. stipulacea was also monitored in four periods. To test the hypothesis th…
Il dovere di proteggere e il principio di non-refoulement. Storia e confinamenti di una legge ancestrale
2019
Il contributo ripercorre la storia dell'asilo ritrovandone le radici nella legge ancestrale dell'ospitalità e nell'antico dovere di proteggere positivizzato, nell'età dei diritti, nel principio di non refoulement affermato dal diritto internazionale dei rifugiati. L'effettività di questo principio viene quindi posta in questione alla luce delle politiche migratorie contemporanee di chiusura dei confini, guardando a come esse si attuano oggi nel contesto del Mediterraneo centrale dove si assiste a un paradossale rovesciamento di ruoli tra chi viola e chi rispetta ancora il dovere di proteggere.
Introduction: Mediterranean Movements and the Reconfiguration of the Military-Humanitarian Border in 2015
2018
This article deals with the transformations occurred in the government of refugees in the Mediterranean since 2013, when the military-humanitarian operation Mare Nostrum was launched by the European Union. The paper analyses how military and humanitarian practices are entangled in governing refugees and develops the notion of military-humanitarianism. The Mediterranean borderzone has undergone radical reconfigurations over the last few years. Particularly, new technologies of control for strengthening the role of the Mediterranean Sea as a pre-frontier of Europe have been put in place. The production and the declaration of a "refugee crisis" in Europe has contributed to producing important …
Mediterranea: Città negata
2020
C’è una città dei morti, in fondo al Mediterraneo, che se i suoi abitanti parlassero ancora racconterebbe tutti gli orrori del misconoscimento della condizione umana, tutti i suoi mali: ogni ingiustizia giace lì, irredimibile. Ma se le città dovrebbero essere quelle dei vivi, più che mai il Mediterraneo è oggi città impossibile, città negata. Perché una città è tale quando una collettività condivide almeno un certo grado di appartenenza ad essa, e ancor di più quando diventa comunità e possiede anche il potere diffuso – seppure solo nelle utopie in misura veramente eguale – di deciderne funzionamenti e modalità di governo. Una città è tale, a prescindere dalle sue dimensioni o dalla moltepl…
Il Mare di mezzo: storie di naviganti, di lotta per il diritto e di luci nel buio della frontiera
2022
This paper analyses the way in which, and the reasons why, the Mediterranean Sea, from being a limes between lands, has become the frontier we know today: the space of an emblematic struggle for law and rights, which contrasts the policies of governments with the forced movements of people in migration and with civil society organizations that try to promote and protect fundamental rights. In this context, the direct experience of some search and rescue missions in the Mediterranean Sea has been used to highlight the extent of this conflict with respect to the violation of the national and domestic legal frameworks carried out by the European states, Italy in the lead, also through the invo…