This paper presents new data describing the Holocene environmental history of the Briaunis palaeolake, Eastern Lithuania. Shortly before 9600 cal yr BP, sedimentation began in an oligotrophic deep-water basin, whereas the Early Holocene instability of the environmental regime caused the influx of detrital sediment into the basin. A birch forest dominated in the surrounding landscapes, and at ca. 9600 cal yr BP, the spread of Ulmus, Alnus, Populus and Corylus began, suggesting a short-lived climatic amelioration. A subsequent drop of the water table and increasing influx of the terrigenous material continued from 9600 to 9300–9200 cal yr BP. The ensuing climatic stability caused the formation of a deciduous forest and the regional spread of Picea. Some instability, i.e. a decline in the thermophilous species, as well as the appearance of boreal and northern alpine diatoms, could be associated with the so-called “8.2 ka event”. This reversal was followed by amelioration and prospering of the water plants typical of the Holocene climatic optimum from 7900 to 7200–7100 cal yr BP. At aproximatelly 6600–6500 cal yr BP, a small rise of the water table was documented and bog-forming processes dominated until ca. 3600–3400 cal yr BP, when a small-scale deepening of the basin occured.
Keywords: Pollen; Plant macrofossils; Diatoms; Vegetation changes; Sedimentation history; Holocene; East Lithuania
The position of offshore ice margins, especially in the Baltic Sea, is poorly known. Based on hydroacoustic surveys, we mapped a field of submarine eskers on the seafloor of the shoal Adler Grund, southwestern Baltic Sea. The eskers comprise discontinuous, branching ridge structures with zigzag-shaped crests. These features are elevated up to 7 m above the surrounding seafloor with slope angles approaching 26o. The ridges are composed of gravel and boulders. Their interpretation as glacio-tectonic features is unlikely due to branching ridge crests and a continuous reflector at the base of several ridges. Based on their morphology and distribution, the ridges are interpreted as concertina eskers formed by meltwater outbursts close to an ice margin. Their good state of preservation indicates that the eskers were most likely formed during the last advance of the Weichselian glaciation across the study region.
Keywords: Multibeam echo sounder; Submarine esker; Adler Grund; Baltic Sea
This paper aims to analyse the sensitivity of patterns of numerically simulated potential sediment transport along the eastern Baltic Sea coast. The study area extends from the Sambian (Samland) Peninsula to Pärnu Bay in the Gulf of Riga. The magnitudes of net and bulk transport depend largely on how the shoaling and refraction of the waves are resolved. The qualitative patterns of net and bulk sediment transport are almost insensitive with respect to the details of wave transformation in the nearshore and with respect to grain size. The overall counter-clockwise transport along the study area contains two persistent reversals along the coast of the Baltic Sea proper and two frequently recurring reversals along the eastern margin of the Gulf of Riga. Individual years with normal levels of wind speed may host completely different patterns of sediment transport. The location of the most persistent convergence and divergence areas of the net transport acceptably matches the granulometric composition of the nearshore seabed up to a few km from the shoreline.
Keywords: Alongshore sediment transport; Coastal processes; CERC model; Geological composition of the nearshore; Baltic Sea; Gulf of Riga
The objective of this study was to analyse changes in the land use patterns of agricultural land and forests in Polish and Lithuanian trans-border rural areas. A studied territorial complex comprises two Polish voivodships (Warmia and Mazury, Podlasie) and two Lithuanian counties (Marijampolė and Alytus). The principal research sites were Polish counties (Polish: powiat, the second-level unit of local government and administration in Poland) and Lithuanian municipalities (Lithuanian: savivaldybė, the second-level unit of local government and administration in Lithuania), which represent corresponding territorial units in the respective national administrative structures. The analysed dataset covers the period of 2005–2010 and supports the identification of changes in the land use structure of farmland and forests which have taken place since the introduction of political and economic transformations in Poland and Lithuania. The dynamics and direction of changes were compared against different historical and economic backgrounds to assess the prevailing trends in land use profiles in both countries.
Keywords: Agricultural land; Forest cover; Land use patterns; Rural areas; Poland; Lithuania
A model of the coastline dynamics along the Palanga Beach, Lithuania is developed through coupling of the GENESIS software with the external wave model RCPWAVE that accounts for the recent bottom topography. Analysis of the calibration and verification results of the coupled model shows that it reproduces the coastline dynamics reasonably well and can serve as an effective tool for coastal management. The largest discrepancies between the observed and modelled behaviour of the coastline occur near the Rąžė River mouth.
Keywords: Coastline dynamics; Model calibration; Model verification; GENESIS; RCPWAVE; Palanga Beach; Lithuania
In this study, three methods of evaporation estimation (temperature-based ETo [evapotranspiration] equations, radiation-based ETo equations, and mass-transfer based ETo equations) were applied to calculate the evaporation from the Curonian Lagoon. Estimation of evaporation by various methods showed that the annual mean of evaporated water from this shallow water basin during 1971–2011 ranged between 512–643 mm (average: 586 mm). The study revealed that Thornthwaite, Schendel, and Vikulina equations gave the most accurate assessment and the lowest uncertainties of evaporation (R of the calculated and the measured data ranged between 0.78–0.96). The value of evaporation depended on differences in estimated water surface area of the basin. The calculated evaporation using a constant surface area differed more than 10% from the one estimated according to the relationship between surface area and water level. However, these differences are minor in the context of the total water balance of the Curonian Lagoon, comprising only 0.06%–0.31% of the total water volume.
Keywords: Evaporation; Estimating methods; Uncertainty; Curonian Lagoon
The removal of ordnance and ammunition followed by high levels of impulsive noise is implemented yearly in the Lithuanian area of the Baltic Sea. During the international naval exercise Open Spirit (Summer 2013), an acoustical survey (using submersible cable hydrophone) was conducted in order to measure the underwater impulsive noise levels produced by controlled detonation and to assess their potential ecological impacts. The findings indicate a high noise energy level of explosions having a particularly small weight of charges, reaching up to 190 dB (in low-frequency bands) and theoretical estimations of the initial shock wave of 276 dB.
Keywords: Acoustics; Underwater explosion; Aquatic life
This paper focuses on the deep geothermal energy utilisation from the Lower Cambrian sandy siltstone aquifer as a potential supply to the district heating system in Nīca, a small municipality in southwest Latvia. Based on this case study, we argue that it is technically and economically feasible to develop efficient geothermal heat stations in small municipalities rich in geothermal resources under three key preconditions: -sufficient extractable heat resources of the aquifer; – ready availability of a nearby deep well; and – a plan for environmentally acceptable disposal of the cooled geothermal water to the surface waters. If these conditions are met, the deep geothermal energy utilisation in a small-scale district heating system might be economically viable and possibly more sustainable than a larger district heating system, where high-pressure re-injection of the cooled geothermal water into deep rock aquifers is necessary.
Keywords: South Baltic Geothermal Region; Rural municipalities; Deep geothermal energy; Cooled brine disposal; Kriging; Deep well restoration
Palaeo-incisions (palaeo-tunnels, tunnel valleys, buried valleys, etc.) comprise the most prominent features in the sub-Quaternary surface covered by the Scandinavian continental ice sheets. An exception is the Scandinavian crystalline bedrock region. Palaeo-incisions are objects of Quaternary geology both from scientific and practical point of view and have been previously mapped along the Lithuanian coastal area using gravimetric and transient electromagnetic methods, complemented by traditional drilling. This paper presents an approach for high-resolution identification of the palaeo-incisions in the Šventoji–Būtingė coastal area of north-western Lithuania. Several geophysical methods have been tested, including shallow seismic reflection profiling, electrical tomography and ground-penetrating radar. A combination of shallow seismic reflection and electrical tomography profiling provides an optimal survey strategy for high-resolution investigations of palaeo-incisions.
Keywords: Palaeo-incision; Gravimetric survey; Seismic survey; Electrical tomography; Ground-penetrating radar; Lithuanian coastal area