Sea Topography of the Ionian and Adriatic Seas Using Repeated GNSS Measurements

The mean sea surface topography of the Ionian and Adriatic Seas has been determined. This was based on six-months of Global Navigation Satellite System (GNSS) measurements which were performed on the Ionian Queen (a ship). The measurements were analyzed following a double-path methodology based on differential GNSS (D-GNSS) and precise point positioning (PPP) analysis. Numerical filtering techniques, multi-parametric accuracy analysis and a new technique for removing the meteorological tide factors were also used. Results were compared with the EGM96 geoid model. The calculated differences ranged between 0 and 48 cm. The error of the results was estimated to fall within 3.31 cm. The 3D image of the marine topography in the region shows a nearly constant slope of 4 cm/km in the N–S direction. Thus, the effectiveness of the approach “repeated GNSS measurements on the same route of a ship” developed in the context of “GNSS methods on floating means” has been demonstrated. The application of this approach using systematic multi-track recordings on conventional liner ships is very promising, as it may open possibilities for widespread use of the methodology across the world.

Disentangling relationships between the amphi-Adriatic Euphorbia spinosa and Balkan endemic E. glabriflora (Euphorbiaceae)

The Mediterranean region is one of the 25 biodiversity hotspots, with several species distributed on both sides of the Adriatic Sea, i.e. on the Apennine and the Balkan Peninsulas. One of these is Euphorbia spinosa, distributed in the coastal regions of the Ligurian, Tyrrhenian, Ionian and Adriatic Seas, whereas its closest relative, E. glabriflora, occurs in continental regions of the western and southern Balkan Peninsula, mostly on serpentine substrates. They differ morphologically, but transitional forms resembling E. glabriflora can be found within the range of E. spinosa and in the overlapping areas of both species, and phylogenetic relationships between them remain unclear. Using nuclear ribosomal ITS sequences, we here show that these two species form a monophyletic group closely related to the E. acanthothamnos alliance, but the relationships between them remain unresolved. Also, amplified fragment length polymorphism (AFLP) fingerprints are weakly structured, but indicate a north-west to south-east trend in genetic differentiation and two main genetic groups; however, these are not entirely congruent with morphological species boundaries. In addition, morphometric analyses indicate only weak differentiation between the taxa, mostly due to occurrence of morphologically transitional forms in contact areas between the two genetic groups. Based on our results we propose to treat both taxa as subspecies of E. spinosa and provide a taxonomic treatment with descriptions. Finally, based on the high genetic variability on the Balkan Peninsula, we hypothesize a trans-Adriatic dispersal from the Balkans to the Apennine Peninsula, probably during the Pleistocene. This is in line with previous studies of different plants with amphi-Adriatic distributions, with the exception that in E. spinosa the distributions on both peninsulas are of similar size, whereas in most other cases the distribution area on the Balkan Peninsula is larger than on the Apennine Peninsula.

Two Seas for One Great Diversity: Checklist of the Marine Heterobranchia (Mollusca; Gastropoda) from the Salento Peninsula (South-East Italy)

The Salento peninsula is a portion of the Italian mainland separating two distinct Mediterranean basins, the Ionian and the Adriatic seas. Several authors have studied the marine Heterobranchia (Mollusca, Gastropoda) fauna composition living in the Ionian Sea, but to date further knowledge regarding this interesting group of mollusks is still needed. Recent studies have corroborated the peculiarity of the Mediterranean Sea showing high levels of endemism and cryptic diversity. On the other hand, marine sea slugs have been revealed to be important indicators of the marine ecosystem’s health, due to their species-specific diet that consist of a vast variety of sessile and benthic invertebrates. A baseline study of the marine Heterobranchia diversity is therefore a necessary step to reveal the hidden diversity and to monitor the possible presence of alien species. The present study shows results from approximately 600 scientific dives carried out during a nine-year period in all of the main submarine habitats of the studied area, while accounting for the marine Heterobranchia from both the Ionian and Adriatic Seas. With this contribution, the list of marine Heterobranchia inhabiting the Salento Peninsula rises to 160. Furthermore, it also reports, for the first time, the presence of one alien species and three new records for Italian waters. Ecological notes and geographical distribution for each added species are provided together with animal iconography, consisting mainly of in situ photographs, for species identification.

Settlement and Spreading of the Introduced Seaweed Caulacanthus okamurae (Rhodophyta) in the Mediterranean Sea

In this study, we report the first finding of the non-indigenous seaweed Caulacanthus okamurae (Rhodophyta) in the Ionian and Adriatic Seas (Mediterranean). Specimens were identified through molecular analyses based on the plastid ribulose-1,5-bisphosphate carboxylase/oxygenase (rbcL) marker. The sequences obtained during this study represent the first molecular evidence of the presence of this taxon in the Mediterranean Sea. Stable populations have been detected in some areas of the Mar Piccolo of Taranto (Italy) and in the whole lagoon of Venice, forming dense patches of low turf that reach high biomasses. Turf-forming algae are common in the intertidal zones of tropical regions, but are rare in temperate ones. The particular environmental conditions of transitional water systems, such as the Mar Piccolo of Taranto and the Venice Lagoon, together with the water temperature increase observed in the last years could have favored the settlement and spread of this introduced species.

Nostoi and Material Culture in the Area of the Classical-Hellenistic Ionian and Adriatic Seas

This chapter draws on a combination of material and epigraphic evidence, presenting and analysing four case studies which indicate that nostoi were exploited by communities so as to define themselves in relation to their neighbours. In this way, nostoi served to shape communal as opposed to personal identity.