Southeastern Mediterranean Research Articles

A dynamic subtropical coastal hotspot of benthic foraminifera in the Southeastern Mediterranean indicates early-stage tropicalization

Due to ongoing ocean warming, subtropical environments are becoming accessible to tropical species. Among these environments are the vermetid reefs of the Southeastern Mediterranean (SEM). In the last decades, these valuable coastal habitats witnessed the proliferation of numerous alien species of tropical origin. Among the meiofauna thriving on these reefs are benthic foraminifera, single cell marine organisms that make a significant contribution to global carbonate production. It has been widely recognized that benthic foraminifera, among other invasive species, thrive in the macroalgal cover, and it has been suggested that their populations are becoming a significant new source of sediment substrate. Here, we report on the first systematic assessment of the population size of the benthic foraminifera, allowing a comparison with data from the native tropical habitat of these species. Our study is based on a seasonal sampling of benthic foraminifera from confined sampling areas at four sites along the vermetid reef platforms of the Israeli SEM coast. Our survey reveals a patchy distribution of each species with peak population densities exceeding 100,000 specimens per m2, making the SEM a hotspot of benthic foraminifera, with population densities comparable to tropical coral reef environments. The assemblages of the SEM hotspot are dominated by cosmopolitan foraminiferal taxa and tropical invaders from the Indo-Pacific (e.g., Amphistegina lobifera, Pararotalia calcariformata, soritids, and Hauerina diversa). In contrast to foraminiferal hotspots in the tropics, which are completely dominated by larger symbiont-bearing taxa, the SEM hotspot stands out due to high abundances of non-symbiont-bearing species Textularia agglutinans and small miliolids. An intriguing observation is the significant heterogeneity in composition and density of foraminiferal assemblages between the vermetid reefs' southern and northern areas (Israel), indicating that the productivity of the dominant species are also modulated by local yet unknown environmental factors.

Abundance, size composition and benthic assemblages of two Mediterranean echinoids off the Egyptian coasts: Paracentrotus lividus and Arbacia lixula

This study is concerned with the variability in abundance, size composition and benthic assemblages of two echinoid species, the common sea urchin Paracentrotus lividus (Lamarck, 1816) and black urchin Arbacia lixula (Linnaeus, 1758) in the Southeastern Mediterranean (SEM) along the coast of Alexandria, Egypt. Four seasonal trips were made during the years 2014–2015 covering 55km of the shore with depths ranging between 3 and 9m. The sea urchin species composition, density and size structure and distribution were compared. The associated macrobenthic invertebrates with prominent presence and biomass were observed as well as other benthic fauna and flora associations. The present results showed that P. lividus was the dominant echinoid spatially and temporally. A. lixula showed frequent occurrence in Sidi Bishr and Sidi Gaber stations in the spring season. The most dominant size class was the medium to large-sized classes for P. lividus and large-sized classes for A. lixula. The commercial size for the edible P. lividus represented 33% of the sampled population. Furthermore, the most dominant macrobenthic assemblages beside the echinoid population were primarily oysters, sea cucumbers, and mussels. Beside these, assemblage of seaweeds (red, green, brown and crustose algae), Porifera, Cnidaria, Crustacea, other Echinodermata, Bivalvia, Gastropoda, Tunicata, Bryozoa and Annelida were found. The present study shows that the investigated area represents stable habitats for the echinoid population with rich and diversified algal assemblages as well as other potential food resources.

Onshore storminess factor: a new tool for regional beach hazard rating and beach safety management

Drowing hazards result from the interaction between bathers and the morphodynamic surf processes related to the regional synoptic setup and regional offshore oceanographic conditions. We focus on the beach hazard rating (BHR) derived from meteorological parameters of synoptic scale that control seasonal swell generation and direction. We suggest a new characterization of the seasonal Mediterranean meteo-oceanographic systems as a relationship between the regional meterological parameters averaged over a given period of time and space and the resulting regional wave climate and direction. Our study area is the entire Mediterranean Sea and its coastlines. We suggest the onshore storminess factor (ONSF) as a proxy to express the amount of energy approaching a given coastal segment, and use ONSF maps of the Mediterranean Sea as a tool for drowning hazard and drowning risk analyses. For beach safety management (BSM), we recommend that the regional ONSF--a macro scale approach--be used before applying a morphodynamic BHR approach, which operates on a micro scale at the local or single beach level. ONSF maps show that the Eastern Libyan, Egyptian, Gaza Strip, Israeli, and Lebanon coasts, all located in the southeastern Mediterranean Sea, are tagged with higher ONSF values. The rest of the coast of Libya and southern Tunis show intermittent ONSF values. The lower ONSF values typically occur along most of the northern and western Mediterranean shores; however most of these shores have very low ONSF values.

Classical Excavations in the Southeastern Mediterranean

Classical Excavations in the Southeastern Mediterranean