Coastal barriers account for approximately one-eighth of the world’s coastline. Barriers are the most common landform type in the southern part of the Baltic Sea area. Despite the long history of ...research, the issue of barrier coast evolution remains unresolved. The topic of this research is to determine the conditions under which the barrier coast evolved in the Holocene and to explain the local, different histories of its development. A 35 km long stretch of the coastal zone in the eastern Pomeranian Bay (southern Baltic) was explored using boreholes, seismoacoustic and GPR profiling, as well as radiocarbon and OSL dating, biostratigraphic studies and lithological analysis. Three main groups of deposits were identified: barrier subsoil deposits, barrier deposits (marine and aeolian sand, as well as interdune peat) and Rega River delta deposits. In the early Northgrippian (~8000 yr b2k), the coastline was located from about 2 to 12 km north of its present position. In the period 8000–6000 yr b2k, the coastline migrated southwards (landwards), initially at a rate of up to 22 m/yr and later up to 2 m/yr. The main driving forces at that time were climate warming and rapid sea level rise. When the Holocene transgression ceased, there were three different histories of the barrier coast development in the study area: a barrier that was still transgressive, a barrier that evolved from transgressive to progradational, and a barrier that evolved from transgressive trough progradational to transgressive again. The main determinants of these different histories were the lithology and relief of the barrier subsoil (accommodation space) and the time-varying amount of sand available for barrier formation, which varied in different parts of the study area.
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Sea-level changes of the Baltic Sea have been in the focus since the beginning of Baltic history studies. The main goal of the study is to reconstruct Holocene sea-level changes in the eastern part ...of Pomeranian Bay and the Szczecin Lagoon. For this purpose, 171 radiocarbon dates were used for the eastern part of Pomeranian Bay and 131 radiocarbon dates for the Szczecin Lagoon. The data allow reconstructing sea-level changes in the last 8500 years in the eastern part of Pomeranian Bay and 7500 years in the Szczecin Lagoon. The sea level 8500 yr b2k was ca. 16 m in Pomeranian Bay, while 7500 yr b2k in the Szczecin Lagoon, it was ca. 8 m below the present sea level. Initially, the fast sea-level rise (up to 9.0 mm/yr) slowed down about 6000 yr b2k to ca. 1.0 mm/yr. In the last 5000 years, the sea level rose at a rate of 0.5 mm/yr in both sites. Analysed data allow distinguishing an extreme event (or events) that disturbed a rather regular course of sea-level rise, which occurred between 7314 and 7022 yr b2k. The history of sea-level changes was similar in the eastern part of Pomeranian Bay and the Szczecin Lagoon despite differences in the geological structure of the pre-Quaternary bedrock and potential various trends in vertical crustal movements. Similarities to some other regions of the southern Baltic and the world ocean allow assuming that sea-level changes in the study area in the last 9000 years in general were eustatic in nature.
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The Younger Dryas-Holocene transition represents a period of significant thermal change, comparable in magnitude to modern warming, yet in a colder context and without the effect of anthropogenic ...disturbance. This is useful as a reference to tackle how biodiversity is affected by temperature in natural conditions. Here, we addressed the thermal change during this period in a southern Baltic coastal lake (Konarzewo Lake, Poland), as inferred by chironomid remains. We evaluated changes in chironomid communities and used Hill numbers to explore how commonness and rarity underlie biodiversity changes attributable to warming. We found evidence of warming at Konarzewo Lake during the Younger Dryas-Holocene transition, with inferred temperatures in the Younger Dryas period supporting the NW–SE gradient in Younger Dryas summer temperatures across Europe. Chironomid communities drastically changed during the thermal transition. However, Hill numbers showed no response to temperature when rare morphotypes were emphasized (order
q
= 0) or a weak response when they were balanced with common morphotypes (order
q
= 1). Hill number of order
q
= 2, emphasizing the most common morphotypes, consistently increased with temperature across different sample sizes or coverages. This illustrates how common morphotypes, rather than the rare ones, may boost biodiversity facing warming.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The Swiss‐Norwegian training model established in 2011 has been used across Europe to infer past mean July air temperatures using Chironomidae subfossils. It combines reference sites from Norway and ...the Swiss Alps but lacks representative localities from the central European plains belt. This gap complicates reconstructions from temperate European latitudes, and thus, a Polish training set (TS) was developed. Data from 102 lakes, mainly from Pomerania and the Masurian Lakelands, as well as the Polish Plain, the Sudetes, and the Carpathian Mountains were included. After selecting and merging suitable chironomid taxa, the Swiss‐Norwegian‐Polish TS includes 357 lakes and 134 chironomid morphotypes, and it has a mean July air temperature range of 3.5 to 20.0 °C. The weighted averaging‐partial least squares (WA‐PLS) and artificial neural network (ANN) transfer function based on the extended TS performs well: R2jack = 0.91/0.95 and root mean squared error of prediction (RMSEP) = 1.39 °C/1.34 °C, respectively. The transfer function applied to the Żabieniec Lake sequence (central Poland) reveals higher summer temperatures (2.5–4.0 °C) for the Lateglacial and for the Holocene (1.0 °C) compared to the Swiss‐Norwegian model. The reconstruction based on the Swiss‐Norwegian TS shows an increasing trend from the Bølling‐Allerød Interstadial to the Meghalayan period, whereas the new model reconstruction shows no increasing trend when using WA‐PLS and a slightly decreasing trend when using ANN. Summer temperatures in the Lateglacial in Żabieniec inferred using the Swiss‐Norwegian TS are consistent with other temperature reconstructions for 50–55°N in Europe, while those based on the Swiss‐Norwegian‐Polish TS (SNP TS) show closer affinity to more western sites than the eastern European ones. Despite being uncommon, the application of ANN can be a good equivalent of the WA‐PLS technique especially in situations where the available database is limited to fewer than a few hundred variables.
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The results of archaeological research carried out on the early medieval stronghold in Santok prove that from the 2
half of the 8
century it functioned in the contact zone between Baltic trade ...centres and inland, as one of the points in the network of goods exchange. We present the centre in a broader context, not only from the perspective of discovered artefacts but from the natural and ideological elements of the landscape of this place created by the communities inhabiting the Warta and Noteć valleys in the 8
and 9
centuries. The settlement was founded in a convergence of waterways in a way that perfectly uses elements of the topography of the area. Wetlands were important ecological niches for residents whose lifestyle was associated with exploring both the valley and upland zones. Santok is difficult to interpret merely as a mere reflection of the practicality of power or economic activity, including manufacturing and trade. It is a clearly legible place in the landscape, with a symbolic structure that represents the concepts of the cosmological order related to the spatial organization of the exchange point and the communication node. So far Santok is the only recognized trading post on a waterway, in this part of the Slavic region, with such an early chronology. Thus we have attempted to present the landscape of this place, considering its many elements, at different levels of perception and in a broad context.
All dunes within a dunefield usually show a similar response to the wind regime. However, in the late‐Holocene coastal dunefield in NW Poland the surface topography suggests that slipface orientation ...may vary significantly with distance from the coast, which is rarely reported in the literature. The dunefield was stabilized with forest in the mid‐19th century, preserving a unique record of atmospheric circulation in the South Baltic region at the end of the Little Ice Age. To elucidate the Holocene processes occurring along the study site a pseudo‐3D GPR data set was collected. Six grids of parallel GPR lines combined with 400 m of GPR profiles (2D) were collected across the dunefield and displayed using GOCAD for interpretation and geostatistical analysis. The geophysical data revealed that the larger dunes almost entirely consist of steeply laminated facies. Most importantly the pseudo‐3D data, supported by geostatistical estimates of strata dip directions, revealed the existence of three zones parallel to the coastline with the mean dip direction almost perpendicular to the coast in the northern coastal strip and almost parallel to it in the southern part. Spreads of the dip directions in pseudo‐3D GPR data sets recorded on the stoss slopes of dunes and crests suggested initial deposition on transverse dunes, which later were transformed into barchanoid dunes. This can probably be linked to changes in the wind regime, i.e. reduction in velocity of the northern and northwestern winds leading to reduced sediment supply from the coast. While the data provide a new interpretation of Holocene dunefield dynamics at this site, they also suggest that the minimum number of pseudo‐3D GPR grids required to establish general trends using geostatistical analysis should be at least 10, with even more data needed at larger, or more complex dunefields.
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The climate variability and related sea-level changes during the Holocene are still under discussion, especially in a regional context. Very little information comes from the southern and ...south-eastern Baltic coast. The aim of the paper is to gain insight on the history of regional environmental changes, particularly sea-level and storminess, and their driving forces. The investigations were located on a peatland on the coast of Puck Lagoon (Gulf of Gdańsk, southern Baltic Sea). The analysis of peat core comprised: radiocarbon dating, analysis of stable isotopes 18O and 13C and chemical components, as well as palynological and diatomic studies. Results showed the 1.0 m peat section accumulated over 1500 years, with a time resolution of 100 years per sample. The average water level in the Puck Lagoon rose by ca. 0.85 m during the last 1500 years in a cyclic mode, with a period cycle of ca. 600–550 years and an amplitude not exceeding 0.5 m. The accelerated sea level rise and frequent storminess occurred during the first half of the Dark Ages (1500−1300 years b2k) and LIA (750−450 years b2k) and since the beginning of the 20th century. Recognized environmental changes are well correlated with both temperature changes in the North Atlantic and changes in total solar irradiance, suggesting synchronous Northern Hemisphere-wide fluctuations. The solar forcing was an important constituent of natural climate variability in the past and of forcing climate warming during modern times - after the Little Ice Age.
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