Santrauka The aim of the study was to analyse the sequence of winter (“warm”) upwelling and lake-effect snow (LES) events that deposited up to 50 cm of snow along the North Estonian coast in January–February 2021. Based on weather and aerological data, four episodes of LES were documented. Heavy, localized lake-effect enhanced precipitation occurred along a 30–50 km wide coastal strip bordering the Gulf of Finland when a cold air mass from the north advected over the warmer, unfrozen sea surface. A temperature difference of up to 20°C was revealed between the air mass temperatures measured at the 850 hPa level and at the sea surface. The LES events, in turn, were preceded by upwelling in the southern Gulf of Finland, which was generated by persisting easterly winds. Even when occasionally interrupted by a wind change, the upwelled water still kept sea surface temperature (SST) in the southern half of the Gulf higher, as documented by the water temperature records from the coastal stations of Estonia, SST and salinity imagery retrieved from the SatBaltyk system, and sea ice distribution charts. Differently from summer (cold) upwelling, winter upwelling brought up warmer (2–4°C) water from the sub-surface layers replacing the already cooled down (0–1°C) surface water. Thus, winter upwelling enhanced LES in two ways. Firstly, by not letting the Gulf freeze over, and therefore by providing a fetch. And secondly, by increasing the SST (and therefore also the 850 hPa level – surface temperature difference) by up to 4°C.
Raktažodžiai sea-effect precipitation; atmospheric instability; warm upwelling; sea surface temperature; sea ice; Baltic Sea
Santrauka One of the United Nations Sustainable Development Goals regarding “conservation and sustainable use of the oceans, seas, and marine resources” emphasizes the urgency of eliminating harmful effects on the sea and its biota, where the role of anthropogenic activities is crucial. The global trend of merchant shipping is increasing, thus enlarging underwater noise levels. As a result, greater noise can harm aquatic animals in their habitats. In the Baltic Sea, the underwater sound pressure levels are now being evaluated utilizing noise measurement, modelling, and mapping. In areas such as narrow ship passages, namely lagoons, channels, or straits, the ambient underwater noise modelling becomes very complex, even though these EU inland waters are regarded by legislation as part of the marine basin. For instance, the Klaipėda Channel (Klaipėda Strait), connecting the Baltic Sea and the Curonian Lagoon, is regarded by the national Lithuanian legislation as part of marine waters, where the environmental status should be evaluated according to the EU Maritime Strategy Framework Directive. In this narrow channel, an alternative to the modelling of ambient sound pressure levels can be applied to understand the long-term trends of vessel-sourced noise emissions. In this paper, an example of application of ship noise emission modelling for a narrow Klaipėda Harbour area is presented, along with the results obtained throughout 2015–2017. The modelled noise levels in the harbour area reached the median levels of 112.5 dB in 2015 and 102.6 dB re 1 µPa2 in 2017. The maximum emitted instantaneous sound pressure levels by ships reached 173.7 dB in 2015 and 179.4 dB re 1 µPa2 in 2017 in the area of interest.
Raktažodžiai Baltic Sea; harbour area; ships source levels; noise predictions
Raktažodžiai spatio-temporal analysis; Mcomp; b-value; Dc-value; Z-value
Šaltiniai The 2011–2012 data on the hydrochemical mode of the transboundary River Viliya (Neris) and two of its tributaries in the territory of the Republic of Belarus and on structure of the phytoplankton community therein are presented. High phytoplankton biomass was determined in the summer period. For the first time, the presence of microcystin synthase genes (mcyE) was detected in the River Viliya (Neris), and four variants of microcystins were determined employing the MALDI-TOF method. Similarities in the species composition (including toxic species) of cyanobacteria from the River Viliya (Neris) and from the Curonian Lagoon of the Baltic Sea were noted. It can be assumed that the phytoplankton community structure of rivers can influence algal community formation in the downstream areas as well as in the coastal estuarine lagoons that eventually receive water from these rivers.
Raktažodžiai biomass; cyanobacteria species composition; toxic species; microcystins
Santrauka The Dizi Series is exposed within the Southern Slope zone of the Greater Caucasus, in the core of the Svaneti anticlinorium. It is mainly composed of terrigenous, volcanogenic and carbonate rocks faunistically dated from the Devonian to the Triassic inclusive. Regional and contact metamorphism of the Dizi Series rocks was studied. It is stated that the degree of regional metamorphism corresponds to the chlorite-sericite subfacies of the greenschist facies, occurring at a temperature of 300–350°C and a pressure of 1.5–2.3 kbar. As a result of the action of the Middle Jurassic intrusive rock bodies, the regionally metamorphosed rocks of the Dizi Series underwent contact metamorphism. Three zones of contact metamorphism were distinguished corresponding to albite-epidote-hornfels, andalusite-biotite-muscovite-chlorite-hornfels and andalusite-biotite-muscovite-hornfels subfacies. Contact metamorphism took place at a significantly higher temperature and lower pressure than the preceding regional metamorphism. The maximum temperature of the contact metamorphism reached ≈ 570°С, while pressure varied within the range of ≈ 0.3–0.8 kbar. The evolution of rock associations of regional and contact metamorphism of the Dizi Series was studied. The fields of facies and subfacies of regional and contact metamorphism are shown in the Ps-T diagram. Three age populations of zircons were identified using U-Pb LA-ICP-MS dating of the diorite-porphyrite intrusion in the Dizi Series: Zrn1 (ca. 2200 Ma) and Zrn2 (458 ± 29 Ma) that were captured by the diorite-porphyrite magma from the ancient magmatic and metamorphic rocks of the crystalline basement, and Zrn3 (166.5 ± 4.6 Ma) that corresponds to the age of diorite-porphyrite crystallization.
Raktažodžiai low-temperature regional metamorphism; contact metamorphism zones; Ps-T conditions of metamorphism; magmatism; U-Pb zircon dating
Santrauka In recent years, Latvian, Lithuanian, and the Oblast of Kaliningrad coastal zones have been experiencing a particularly intense and rapid anthropisation of the coastline due to political, social, and economic changes at the end of the Soviet period. These pressures are exerting on a highly sensitive environment, which has remained relatively untouched by any major development due to the militarisation of the coasts. The human stakes increased considerably in the coastal zone of the south-eastern Baltic with tourism, industrial development, and urban expansion. The environmental impacts and issues of the post-soviet anthropisation are analysed in this article through a bibliographic compilation related to the evolution of the coastal management policies reconciling environmental protection and economic development.
Raktažodžiai environmental issues; coastal zone; coastal management; anthropic pressure; South-Eastern Baltic
Aldona Damušytė, Miglė Stančikaitė, Algirdas Girininkas, Tomas Rimkus, Linas Daugnora, Žana Skuratovič, Domas Uogintas, Darius Valūnas, Giedrė Vaikutienė, Vladas Žulkus
Raktažodžiai lithology; grain-size; pollen; palaeoenvironmental dynamics; Final Palaeolithic; Eastern Baltic
Santrauka This article presents results of the test conducted on the undrained shear strength of till clayey soils of Eastern Lithuania, which are characterized by rigid and very stiff consistency and low plasticity. According to the classification of soils presented in LST EN ISO 14688–2:2018 Geotechnical Investigation and Testing – Identification and Classification of Soil − Part 2: Principles for a Classification, the tested soils are classified as sandy low plasticity clays. The undrained shear strength was tested using the triaxial compression (unconsolidated undrained) method. The test results showed that peculiarities of the particle size distribution had a crucial impact on the undrained strength of these soils, i.e. on the correlation of clay and fine silt fractions with the rest of soil components.
Raktažodžiai particle size distribution; tills; optimal soil mixture; soil framework