Search results for "Ocean"

2017

From 2000 to 2015, tsunamis and storms killed more than 430,000 people worldwide and affected a further >530 million, with total damages exceeding US$970 billion. These alarming trends, underscored by the tragic events of the 2004 Indian Ocean catastrophe, have fueled increased worldwide demands for assessments of past, present, and future coastal risks. Nonetheless, despite its importance for hazard mitigation, discriminating between storm and tsunami deposits in the geological record is one of the most challenging and hotly contended topics in coastal geoscience. To probe this knowledge gap, we present a 4500-year reconstruction of “tsunami” variability from the Mediterranean based on str…

Preliminary patterns of distribution and abundance of loggerhead sea turtles, Caretta caretta , around Columbretes Islands Marine Reserve, Spanish Me…

2003

Aerial surveys were conducted to estimate the abundance and distribution of loggerhead turtles (Caretta caretta) in the Columbretes Islands Marine Reserve and surrounding waters (western Mediterranean). Four surveys were carried out during 2000 and 2001, following the line transect methodology. Loggerheads appeared to be present at high densities in the area throughout the whole year, although density varied between seasons, being more abundant during the spring. Mean density in the study area was 0.322 turtles/km2 (range 0.200–0.516) and the mean abundance was 1,324 turtles (range 825–2,124). The turtles were distributed homogeneously throughout the study area, we found no difference in lo…

The possible influence of sea level rise on the precarious dunes of Devesa del Saler Beach, Valencia, Spain

1991

The Saler Beach dune field in Spain was partially destroyed between 1970 and 1973 due to building development. Presently great efforts to restore some dunes has begun. The possible consequence of a sea level rise for the Saler dune field is discussed according to different scenarios.

Littoral Demosponges from the Banks of the Strait of Sicily and the Alboran Sea

1987

The material of this study has been collected from the South-Western Mediterranean in the course of two expeditions by the Italian Research Vessel “Bannock”. The primary collection method employed was SCUBA diving. The sampled area is affected by an important inflow of water from the Atlantic. Fifty-nine species have been studied. One of them, Stylostichon equiosculatus, is new to science. Some ecological considerations are also discussed.

Holocene millennial-scale productivity variations in the Sicily Channel (Mediterranean Sea)

2008

[1] The calcareous nannofossil assemblages of Ocean Drilling Program Hole 963D from the central Mediterranean Sea have been investigated to document oceanographic changes in surface waters. The studied site is located in an area sensitive to large-scale atmospheric and climatic systems and to high- and low-latitude climate connection. It is characterized by a high sedimentation rate (the achieved mean sampling resolution is <70 years) that allowed the Sicily Channel environmental changes to be examined in great detail over the last 12 ka BP. We focused on the species Florisphaera profunda that lives in the lower photic zone. Its distribution pattern shows repeated abundance fluctuations of …

Mediterranean Coastal Lagoons

2018

On the eastern coast of the Iberian Peninsula—between the Ebro Delta and Cape Palos—the conditions during the Pleistocene, and especially after the Flandrian transgression, favoured the development of beach barrier systems and lagoons along large segments of the coast. The very small tidal range made connections between the sea and lagoons difficult, and this favoured sedimentation processes, which was often accelerated by human activity. Three very different sectors have been differentiated: the Gulf of Valencia, where the largest number of lagoons is found; the cliffed Betic structural sector between Cape Sant Antoni and Cape de les Hortes, in which there are just a few very small lagoons…

Trace element accumulation and elutriate toxicity in surface sediment in northernTunisia (Tunis Gulf, southern Mediterranean)

2017

International audience; Metal concentrations in sediments were investigated in the Gulf of Tunis, Tunisia, in relation to anthropic activities along the Mejerda River and Ghar El Melh Lagoon, with effluents discharged into the gulf. Distribution of grain size showed that the silty fraction is dominant with 53%, while sand and clay averages are 34 and 12% respectively. Zn concentration increased in the vicinity of the Mejerda River while Pb was at its highest levels at the outlet of Ghar El Mehl Lagoon. Sediment elutriate toxicity, as measured by oyster embryo bioassays, ranged from 10 to 45% abnormalities after 24 h, but no relation was found between metal concentration and sediment toxicit…

Human settlements in the Mediterranean and the sea level changes from 12 ka to the present

2012

Understanding past sea-level change plays an important role in determining the underlying causes, and also allows the extrapolation of past sea levels to locations and epochs for which there are no instrumental data. A compilation of global sea-level estimates based on deep-sea oxygen isotope ratios at millennial-scale resolution or higher was published since ‘70. These global sea level curves do not take in account isostasy and tectonics. Observed sea level change can be reconstructed from dated fossils, coral reef terraces, speleothems, emerged and forming terraces on coastal areas, archaeological and other markers well connected with sea level. Because of the lack of coral reefs in the M…

Sedimentary, stable isotope and micropaleontological records of paleoceanographic change in the Messinian Tripoli Formation (Sicily, Italy)

2002

Abstract The Tripoli Formation (6.96–5.98 Ma) of the Central Sicilian Basin provides a good record of the paleoceanographical changes that affected the Mediterranean during the transition from slightly restricted conditions to the onset of the Messinian Salinity Crisis. The Falconara/Gibliscemi section has been selected for an integrated approach at a high resolution scale using sedimentology, stable isotopes of the carbonates and microfossils. The sedimentary succession includes 46 precession-controlled cycles resulting from the periodical increase in biosiliceous productivity (diatomites) that followed the deposition of marls and pinkish laminites, which appear as sapropel-type deposits i…

Astronomic forcing on the planktonic foraminifera assemblage in the Piacenzian Punta Piccola section (southern Italy)

2006

[1] A high-resolution quantitative analysis of the calcareous planktonic assemblages (planktonic foraminifers and calcareous nannofossils) at the Punta Piccola section (at the base of which, the global standard stratotype-section and point of the Piacenzian stage is defined) provided a more accurate biostratigraphy for the Mediterranean middle Pliocene (2.6–3.6 Ma). In particular, an astronomically calibrated age of 2.87 Ma was estimated for the Pliocene first occurrence of Neogloboquadrina atlantica instead of the younger previously proposed age of 2.72 Ma. Spectral analysis performed on the Globigerinoides species (spp.) planktonic foraminifera assemblage along with cross-spectral analysi…