[en] The harmonic constants of the tides at Alexandria, in the eastern Mediterranean sea, have been recalculated by means of a new method. Long period evolution of the sea level in the years 1985-1986 has been also considered

[en] Black Sea, Aegean, Mediterranean and Marmara Sea, which surround the Turkey, have not been examined with respect to the Geological, Geophysical and other natural sciences sufficiently. In fact, it is not attach importance the Turkish seas adequately and abandoned with respect to the scientific researches. The most important reason of this situation is the lack of the education of the Marine Sciences in the Turkish Universities. In this study, it is tried to construct a crustal structure data base of the surrounding seas of the Turkey by collecting crustal structure data sets done by different authors in different times so far. The data acquired in the base are collected from different data base sources by dragging. The Moho depth in the eastern and western basin of the Black sea is 22 km and 19 km, respectively. In the Marmara Sea the Moho depth is 24 km. The moho value in the southern Aegean is 20 km, in the northern Aegean the moho depth is 30 km. on the other hand, the moho depth value in the eastern and western basin of the Mediterranean Sea are 15-20 km and 25-30 km, respectively

[en] Seabed sediment samples were collected in 1998, 2000 and 2001 at 20 sites located in the Baltic Sea and 4 sites in the Skagerrak. The objectives of the sampling campaigns were (i) to establish the coastal sediment distribution of ¹³⁷Cs, (ii) to evaluate the vertical core distribution of ¹³⁷Cs, (iii) to study the sediment accumulation rates, and (iv) to assess the sediment inventories of ¹³⁷Cs. The results show a very high variation in ¹³⁷Cs concentrations and an almost 100-fold difference in inventories, showing predominance of Chernobyl derived ¹³⁷Cs in the Baltic Proper compared to the western Baltic and the Skagerrak areas. Sediment accumulation rates were highly dependent on sediment types and ranged from 0.05 to 1.8 cm/y

[en] We studied the currents mode of the Azov Sea on the basis of instrumental measurements of R/V Deneb in 2018 and 2019. Using ADCP current meters, water exchange between the Azov Sea and the Black Sea through Kerch Strait was estimated. The very strong dependence of the current velocities on the wind speed and direction was shown. With moderate northerly winds, the advection of water to the south to the Black Sea can be 5–6 times more than to the north to the Azov Sea. With southern winds the entire studied cross section could be filled with water of the northern component with a velocity and volume up to 30 times higher than the average discharge of the Don River, which is typical of the present low-water period. On the basis of instrumental measurements, the drift nature of the currents in the Azov Sea was confirmed and flows of saline Black Sea waters were recorded. Based on the results of field observations of the Southern Science Center, Russian Academy of Sciences, a classification of water stratification in Taganrog Bay was constructed, four stratification types were defined, and the restructuring of types of stratification in connection with the salinization of the sea was noted.

[en] Tidal sand ridges are large-scale rhythmic bedforms that are observed on the offshore parts of shelf seas where sand is abundantly available. Spacings between successive ridges are several kilometres, they evolve on centennial time scales, and their crests are cyclonically rotated with respect to the direction of the principal tidal currents. Here, an overview will be presented of the current knowledge about these ridges with respect to their manifestation in different seas, their observed behaviour, the basic mechanisms that explain their initial formation and their evolution towards finite heights and the ability to model them. It will be shown that both tides, waves and changes in mean sea level have a profound impact on the evolution of the ridges.

[en] In this paper the eigenperiods of the Tyrrhenian sea are examined by an hydrodinamical model in two dimensions. The knowledge of these eigenperiods is important to evaluate the seiches that often appear, in some point or circumstance, stronger than the tides. This investigation is performed by energizing the basin through the Sardinia channel, in the same way as it was already done for the tides. This excitation simulates a large set of waves inducing oscillations inside the basin. The periods of the waves are narrow and their amplitude equal. An analogous method of investigation is that of the fluorescence. In addition, the results are compared with those previously obtained leaving the basin swinging, after having increased the sea level by an uniform displacement. The response of the bidimensional model agrees with that of a monodimensional one as far as possible; thus the last one can give useful information, also for a sea that does not have a channel shape, like the Tyrrhenian Sea. Nevertheless, this basin has other openings, besides the Sardinia channel, it seems that they do not influence the eigenperiod behaviour. This has been confirmed by performing the same computations over a sea 500m less deep: the uniform lowering of the sea surface is equivalent to close the four minor openings. The results carried out in this case agree with the previous one. Among all the periods pointed out by our investigation, one is always exhibited in every point and by each system. The period is that of 5.70h and it can be considered a fundamental mode of the Tyrrhenian Sea

No abstract available

[en] In the framework of the developments of the European system RODOS (Real-time On-line DecisiOn support System) for emergency response to nuclear accident, the computer code POSEIDON, that was developed to assess the radiological consequences of radioactive releases into marine environment, was adapted to cope with emergency conditions, in situations of radioactive discharges into the oceans from direct deposition from the atmosphere, sunken ships and containers, from discharges of rivers and estuaries and from coastal run-off. Based on the box model developed within the 'Marina' project, POSEIDON can calculate the dose effects from radionuclide releases in the coastal waters of Europe integrated over long time periods. A dynamic food chain model was implemented to deal with the short-term dynamical uptake of radioactivity by specific marine plants and organisms. POSEIDON has been installed on a UNIX platform to be fully compatible with RODOS input/output databases and on a Windows platform with an interface based on web technology. The 3D hydrodynamic model THREETOX is a part of the POSEIDON/RODOS system. It has been applied to coastal areas of the Baltic Sea, the Black Sea, and the North Sea, to derive the parameters for a flexible system of well-defined model compartments to be adapted to emergency conditions. The activity concentrations in water and in the marine food web were calculated by means of POSEIDON for radioactive fallout resulting from bomb testing, from the Chernobyl accident, and from routine discharges from nuclear facilities. POSEIDON's model results were compared with measurement data, and with calculation results from THREETOX. The model results agreed with the measurement data sufficiently

[en] The authors measured the thermoluminescence (TL) depth of the GT89/3 shallow-water Ionian sea core. This profile has been transformed into a time series using the accurate sedimentation rate previously determined by radiometric and tephroanalysis methods. The TL measurements were performed in samples of equal thickness of 2 mm, corresponding to a time interval of 3.096 y. The TL time series spans ∼ 1800 y. The DFT power spectral densities in the decadal periodicity range of this TL series show significant periodicities at 10.7, 11.3 and 12 y closely similar to the periodicities present in the sunspot number series. These results confirm that the TL signal in recent sea sediments faithfully records the solar variability, as we previously proposed

No abstract available