Adriatic Sea Basin Research Articles

Nuclear and mitochondrial DNA sequence data reveal the evolutionary history of Barbus (Cyprinidae) in the ancient lake systems of the Balkans

Freshwater fauna of ancient lakes frequently contain endemic taxa thought to have originated during the long existence of these lakes, yet uncertainties remain as to whether they represent distinct genetic lineages with respect to more widespread relatives and to the relative roles of isolation and dispersal in their evolution. Phylogenetic analyses of sequence variation at nuclear and mitochondrial genes were used to examine these issues for the freshwater fish genus Barbus in two European ancient lake systems on the Balkan Peninsula. The nuclear and mitochondrial data yielded concordant phylogeographic patterns though incomplete sorting of nuclear haplotypes between some mitochondrial clades was detected. The distributions of two currently recognized species investigated here do not match the distributions of evolutionary lineages revealed by phylogenetic analyses. The Prespa barbel, Barbus prespensis, is not endemic to the lakes Prespa as previously thought but is instead found to be widespread in the south-eastern Adriatic Sea basin, with a distribution largely corresponding to the basin of the now extinct Lake Maliq historically connected with Lake Prespa. On the other hand, a cryptic phylogenetic subdivision in a widespread species, B. rebeli, was discovered to be more distant from B. rebeli than from other Barbus species and to be endemic to the system of connected lakes Ohrid and Shkodra. The division coincides with the hydrogeographical boundary delimiting distributions of other freshwater fishes, and we suggest that this newly discovered evolutionary lineage represents a distinct species. These findings support the emerging pattern that endemic taxa have evolved not through isolation of individual lakes, but in systems of currently and historically interconnected lakes and their wider basins.

Classification of Cyclone Tracks over the Apennines and the Adriatic Sea

Abstract Cyclones that appear in the Adriatic Sea basin strongly influence the climate and weather conditions in the area. In particular, apart from the usually mild climate, cyclone activity in the Adriatic and the central Mediterranean Sea provide both the main hydrological forcing and the trigger mechanisms for a range of extreme weather phenomena. Therefore, a basic understanding of the cyclogenesis over the Adriatic Sea is essential. In particular, the classification of different types of cyclogenesis in the area is fundamental because it will help the understanding and prediction of the relevant weather phenomena. In this study, based on the analysis of the 4-yr (2002–05) operational European Centre for Medium-Range Weather Forecasts T511 dataset, various types of cyclone tracks are classified and the mesocyclogenesis areas in the vicinity of the Adriatic Basin are isolated. This analysis indicates that the following four types of cyclogenesis over the Adriatic Sea can be identified: 1) type A: cyclones connected with preexisting Genoa cyclones [with two subcategories, (A-I) continuous track: Genoa cyclones crossing over the Apennines to the Adriatic Sea, and (A-II) discontinuous track: new surface cyclones generated over the Adriatic Sea under the influence of a parent cyclone generated in the Gulf of Genoa (Genoa cyclones) and moving toward the Adriatic but blocked by the Apennines]; 2) type B: cyclones developed in situ over the Adriatic Sea without any connections with other preexisting cyclones in the surrounding area; 3) type AB: mixed types A and B cyclones, including cases where two cyclones coexist and stride over the Apennines (twin or eyeglass cyclones); and 4) type C: cyclones moving from the Mediterranean Sea, but not from the Gulf of Genoa (non-Genoa cyclones) [with 2 subcategories: (C-I) continuous track: a non-Genoa cyclone is able to cross over the Apennines to the Adriatic Sea continuously, and (C-II) discontinuous track: a non-Genoa cyclone is blocked by the Apennines and a new surface cyclone is generated over the Adriatic Sea]. The relevant dynamics of the above types of cyclones are discussed along with characteristics of the cyclones and their synoptic situations at the lower and upper troposphere.

Water resources and waste water management in Bosnia and Herzegovina, Croatia and the State Union of Serbia and Montenegro

This work provides an inventory of water resources and presents the current status of water supply, water quality as well as wastewater management in Bosnia and Herzegovina, Croatia and the State Union of Serbia and Montenegro, established after the break-up of the former Yugoslavia. All three countries are very rich in water resources, pertaining in a large percentage to the Adriatic and Black Sea basins. However, this richness is not adequately reflected in the current status of the public water supply. Water supply is satisfactory only in bigger cities, whereas rural populations still largely depend on the local sources. Furthermore, with respect to integrated water management, there is a big discrepancy between the capacities of water supply and drainage and those for municipal and industrial wastewater treatment. Only a small percentage of wastewaters receive at least some treatment, putting those receiving natural waters at considerable risk. Nevertheless, available reports on the water quality of ambient waters do not reveal the existence of this problem on a wider scale, but indicate only few hot spots. Microbiological pollution near big cities and patchy elevated levels of heavy metals and organic pollutants around industrial plants and agricultural lands belong to these exceptions. Such a relatively favourable situation is, partly, a consequence of a significant decrease in economic activities, which is characteristic of all transition countries, but it also reveals the impact of the recent wars in the region. Political and military conflicts in the region generated mutual distrust and lack of cooperation between the three countries. However, attempts are being made to resolve most of the issues related to cross-border contamination by signing international and regional treaties. As a part of pre-accession activities, all three states are harmonizing their legislation with the EU and are joining scientific projects on the water protection of other western countries. This is expected to bring considerable benefits to the local population and to make economic development more vigorous.

Microalgal lipid markers for paleoclimatic research

Primary producers, mainly represented in the marine environment by microalgae, synthesize a wide variety of lipid constituents, some of which are recognized as ‘biomarkers’ that can be used to identify sources of organic matter. Furthermore, as phytoplankton rapidly reflect climate variations, the identification of organic matter in sediments may help to understand present or ancient specific environmental conditions. To highlight differences in some lipid constituents (hydrocarbons, sterols and fatty acids) of different taxa of microalgae, we determined these compounds in the diatom Cylindrotheca closterium and dinoflagellate Scrippsiella trochoidea isolated from the Adriatic Sea and grown in batch cultures. Total lipids were extracted in chloroform-methanol and, after separation, analysed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The only hydrocarbons present in these species were cis-3,6,9,12,15,18-heneicosahexaene (HEH) and squalene. Analysis of sterols in C. closterium revealed that only 4-desmethylsterols were present. Conversely, in S. trochoidea, 2 different groups of sterols (4-desmethylsterols and 4a-methylsterols) were identified. Besides the fatty acid 16:0, which predominated in both species, high percentages of 16:1n-7 and 20:5n-3 were observed in C. closterium, whereas 18:4n-3 and 22:6n-3 were detected in S. trochoidea. Differences in lipid patterns were observed between C. closterium and S. trochoidea. These differences might help understand the Adriatic Sea Basin’s paleoclimatic history.

Plinian activity during the early eruptive history of the Sabatini Volcanic District, Central Italy

The early activity of the Sabatini Volcanic District (SVD; central Italy) was characterised by highly explosive eruptions that produced widespread subplinian and plinian fall deposits. In this study, four major eruptive units—informally named as units A, B, C and D—were recognised in the 514–449 ka age interval. In particular, unit D was emplaced during the early phase of the 449 ka Tufo Rosso a Scorie Nere pyroclastic flow-forming eruption, the most important event in the whole SVD activity history. Estimates of relevant eruptive parameters indicate tephra fall volumes up to 4 km 3 for individual units, peak eruption column heights in the range of 14–29 km and corresponding mass eruption rates of 7.8×10 6–1.3×10 8 kg/s. Isopach and isopleth maps of fallout deposits—as well as the distribution of the proximal lag-breccia of the Tufo Rosso a Scorie Nere—consistently indicate a common vent area, which does not correspond to any volcanic centre identified up to now in the SVD. This was located along NE–SW-trending tectonic lineaments that also controlled the location of the other major volcanic centres of the SVD. The characterisation by means of field aspects, grain size, componentry and density and chemical composition of juvenile clasts, renders the studied fall deposits as valuable stratigraphic markers for the SVD and well beyond it. In fact, their wide areal dispersals toward the E and SE may allow correlations on a regional scale for the Quaternary successions of intermountain basins of the Central Apennine and the Adriatic Sea basin successions. Finally, the correct identification of distal tephra from plinian and co-ignimbrite plumes and their attribution to specific explosive eruptions of the SVD and the other volcanic districts of the Roman Province—rather than to local intra-Apennine centres—provides crucial implications for geodynamic reconstructions.

ESTIMATION OF NOBLE CRAYFISH (ASTACUS ASTACUS L.) POPULATION SIZE IN THE VELIKA PAKLENICA STREAM (CROATIA)

Astacus astacus is one of four native European crayfish species living in Croatian freshwaters. It is naturally distributed in rivers belonging to the Black Sea Basin. To some rivers of the Adriatic Sea Basin, however, it had been introduced by man. According to the information from local people it is most likely that A. astacus has been introduced into the Velika Paklenica Stream during the first half of the 20 th century. Our study stream, draining the Velebit Mountain, is situated in Paklenica National Park, Middle Adriatic. The fieldwork of our study was performed during July 2000 and 2002, respectively. To estimate the population size we used mark-recapture techniques (Jolly-Seber Method, Schnabel Method and Schumacher and Eschmeyer Method). Crayfish were trapped with baited LiNi traps that were set along the stream banks at 10 m intervals and left there overnight. Caught animals were individually marked by piercing holes into the uropods and telson and then released. In July 2000 we caught 233 crayfish in total, from which 70 specimens were trapped more than once. In July 2002 we caught 296 crayfish, from which 86 were trapped more than once. Differences in the population size between the two years are discussed.

DISTRIBUTION OF AUSTROPOTAMOBIUS PALLIPES (Lereboullet) IN CROATIA AND NOTES ON ITS MORPHOLOGY

In order to get a better insight into the distribution of white-clawed crayfish (Austropotamobius pallipes) in Croatia, we pooled together all of the available historical data and recent ones. The historical data on the distribution were compiled from the literature and the Croatian Natural History Museum collection, while fieldwork, to evaluate the current distribution of crayfish, took place from 1995 to 2003 on all types of suitable habitats. The distribution of Austropotamobius pallipes is restricted to limestone region and therefore the species is found widely spread in rivers belonging to the Adriatic Sea basin (from the NW to the SE part of Croatia). Those waters are mainly unpolluted and substrate of the bottom consists of rocks and stones and crayfish could be found near banks, where the current is slower and where aquatic plants are abundant. During our research we also occasionally found crayfish in subterranean habitats. Nevertheless, they show no troglomorphic adaptations as they probably enter underground habitats accidentally from original epigean populations. According to the literature data in coastal rivers, apart from A. pallipes, lives A. torrentium. But to date, we have not yet personally recorded its presence there, while we recorded presence of Astacus astacus. While studying the data from literature, we were frequently confronted with contradictory findings. Consequently, we are planning intensive field research in coastal region to get a clear picture on detailed distribution of freshwater crayfish in that part of Croatia.

The Adriatic Sea General Circulation. Part I: Air–Sea Interactions and Water Mass Structure

Abstract A comprehensive historical hydrographic dataset for the overall Adriatic Sea basin is analyzed in order to define the open ocean seasonal climatology of the basin. The authors also define the regional climatological seasons computing the average monthly values of heat fluxes and heat storage from a variety of atmospheric datasets. The long term mean surface heat balance corresponds to a heat loss of 19–22 W m−2. Thus, in steady state, the Adriatic should import about the same amount of heat from the northern Ionian Sea through the Otranto Channel. The freshwater balance of the Adriatic Sea is defined by computing the average monthly values of evaporation, precipitation, and river runoff, obtaining an annual average gain of 1.14 m. The distribution of heat marks the difference between eastern and western Adriatic areas, showing the winter heat losses in different parts of the basin. Climatological water masses are defined for three regions of the Adriatic: (i) the northern Adriatic where seasonal ...

Dealing with the problem of eutrophication in the Adriatic Basin: the institutional framework and policies

The process of eutrophication in the Adriatic Sea Basin has emerged over recent decades as a problem that demands special consideration and treatment; one of the most important reasons is the damage to the economy due to its undesired effects. Scientific knowledge concerning this process, while not exhaustive, is sufficient as a basis for directing action. But the experience acquired to date demonstrates that scientific knowledge alone cannot steer practical action, assuring the use of all existing (limited) knowledge to define the best practicable actions in a given time and place. In other terms, the institutional framework has not been able to use this knowledge for improving the environmental state of the Basin. To overcome this unsatisfactory situation, a different definition of the problem is proposed, as well as a different way for designing suitable solutions.

Physical properties of the lithosphere—asthenosphere system in Europe

All the geophysical fields considered evidence a clear structural difference between the Adriatic Sea-Ionian Sea basin on one side and the Tyrrhenian Sea-Western Mediterranean basin on the other. The former displays continental type characteristics, while the latter shows features definitely related to young ocean basins. Lateral variations in the thickness of the high-velocity sub-crustal layer, the “lid”, are clearly evidenced in the whole European area. The lateral changes in the shear-wave velocities of the lithosphere-asthenosphere system are quite pronounced. Gravity data imply a positive density contrast (0.03–0.07 g/cm 3) in the upper mantle related to almost aseismic high-velocity lithospheric roots, which seem to characterize many orogenic belts. The analysis of a transect along the longitudinal axis of the Alps seems to indicate that relevant lateral variations in density are present in the lithospheric part of the mantle.