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This paper presents a case study from the Hiem cave (Hoà Bình province, North Vietnam) showing how a multidisciplinary approach in archaeological research can develop knowledge on the everyday life of the hunter-gatherer Hoabinhian groups occupying the cave during the early Holocene (8500-8200calBC). The archaeological analysis presents the characteristic Hoabinhian artefacts and their usage, while archeozoological, malacological and archaeobotanical research throw light on the way of life, including plant and animal elements of a daily diet as well as the settlement seasonality of the cave.

Despite the increasing interest in spring-fed fens’ sediments as a palaeoenvironmental archive, their potential as high-precision climatic records is rarely used to its full extent. Here, we present a detailed early to mid-Holocene record of environmental changes in the Turtul hanging spring-fed fen, northeastern Poland, to test whether the well preserved and accurately subsampled alternating peat and tufa sediments allow us to recognise short-duration local and regional climatic changes. Our reconstructions are based on a loss-on-ignition analysis of the sediment, carbon and oxygen stable isotope values of tufa, and biotic proxies: plant macrofossil and malacological analyses. A detailed environmental reconstruction was possible due to the combination of detailed sampling (1 cm intervals) and high sediment accumulation rates. The two sediment sequences collected from the fen revealed the congruent palaeoenvironmental history; however, the temporal shift associated with the distance of the coring site from the water outflow was also apparent, stressing the need for careful selection of the coring site in palaeoenvironmental research. Peat deposition at Turtul started at 10,300 cal yr BP; however, tufa precipitation did not begin before 9250 cal yr BP. During the most active tufa deposition, from 7850 to 6100 cal yr BP, a high sedimentation rate was observed (0.11–0.25 cm yr−1). We found several abrupt and short-duration declines in carbonate deposition corresponding to climatic fluctuations recorded in geological archives from the southeastern Baltic region. The carbonate drops at 8200–8130, 7900–7850, 7400–7300, 6600–6500, 5980–5870 and 5400 cal yr BP were associated with climate cooling or drying, whereas those at 10,200–9250, 8450–8340 and 6160–6100 cal yr BP can be attributed to drying with no cooling. We conclude that the evident sensitivity of the Turtul fen to climatic shifts that emerge from our high-resolution (one sample every 17 years on average) reconstruction complements the still rare high-resolution palaeoenvironmental records in the area.

Northern peatlands store globally-important amounts of carbon in the form of partly decomposed plant detritus. Drying associated with climate and land-use change may lead to increased fire frequency and severity in peatlands and the rapid loss of carbon to the atmosphere. However, our understanding of the patterns and drivers of peatland burning on an appropriate decadal to millennial timescale relies heavily on individual site-based reconstructions. For the first time, we synthesise peatland macrocharcoal re-cords from across North America, Europe, and Patagonia to reveal regional variation in peatland burning during the Holocene. We used an existing database of proximal sedimentary charcoal to represent regional burning trends in the wider landscape for each region. Long-term trends in peatland burning appear to be largely climate driven, with human activities likely having an increasing influence in the late Holocene. Warmer conditions during the Holocene Thermal Maximum (similar to 9e6 cal. ka BP) were associated with greater peatland burning in North America's Atlantic coast, southern Scandinavia and the Baltics, and Patagonia. Since the Little Ice Age, peatland burning has declined across North America and in some areas of Europe. This decline is mirrored by a decrease in wider landscape burning in some, but not all sub-regions, linked to fire-suppression policies, and landscape fragmentation caused by agricultural expansion. Peatlands demonstrate lower susceptibility to burning than the wider landscape in several instances, probably because of autogenic processes that maintain high levels of near-surface wetness even during drought. Nonetheless, widespread drying and degradation of peatlands, particularly in Europe, has likely increased their vulnerability to burning in recent centuries. Consequently, peatland restoration efforts are important to mitigate the risk of peatland fire under a changing climate. Finally, we make recommendations for future research to improve our understanding of the controls on peatland fires.(c) 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

This paper summarises the results of multidisciplinary research, including pollen, plant macroremains, diatoms, Cladocera, molluscs and geochemistry from a 14C dated core and geomorphological records, which reconstruct the palaeoenvironmental conditions faced by Late Palaeolithic hunter-gathers in western Poland. Particular attention was paid to evidence for both human activity and the degree to which Late Palaeolithic groups may have affected the local environment, as recorded by the biogenic sediments in lakes located close to their campsites. Vegetation first appears locally in the Oldest Dryas, and consisted of subarctic tundra vegetation. During the Bølling period the landscape was generally open, with dwarf shrubs and scattered patches of Juniperus and Hippophaë shrubs. Betula (tree birch) expanded locally in the area only in the later Allerød; during the second part of the Allerød period, Pinus and Populus joined birch as a sparse woodland developed. During the Younger Dryas, the landscape changed significantly in comparison to the preceding warm period, as result of cooling and drying of the climate. The presence of microscopic charcoal and charred herbaceous plant particles made it possible to detect human activity. These analyses allowed us to reconstruct fire events near the site during its occupation by Hamburg and Federmesser cultural groups. An increase in the proportion of biogenic elements such as Na, K and Mg in the sediments indicate soil erosion, reflecting the activity of Hamburg groups. A relative increase in the frequency of Cladocera which favour eutrophic and turbid water was recorded in the period linked to Federmesser group activities. The intense use of this area was also indicated during the Younger Dryas.

Shell middens are common finds recorded at Polish archaeological sites dating from the Neolithic to Iron Age; however, very little is known about the acquisition and exploitation of mussels by preh...

Calcite cements are found within the glaciotectonically-deformed coarse-grained glaciofluvial sediments of the Saalian age (MIS 6) at the Koczery site (E Poland). Their sedimentation was controlled by the occurrence of permafrost (Mleczak et al., 2021). Under these conditions, aggradation rate of a glaciomarginal fan was high, and freezing of freshly-deposited sediments was relatively quick. Advancing ice sheet deformed these frozen glaciofluvial sediment in its foreland, creating single faults along with gently and tight folds. These deformed sediments were covered with a subglacial till creating a dome-like shaped landforms reassembling a Cupola hill. This calcite-cemented conglomerate occupies the uppermost part of coarse-grained glaciofluvial sediments. Its thickness ranges from 0.02–0.05 m up to 0.70 m and depends on the inter-limb angle of folds. The higher the inter-limb angle of folds, the thicker the conglomerate. Its greatest thickness is generally recorded on the lee side of major bed obstacles, i.e. glaciotectonically-deformed folds, in this case.Precipitation of calcite within the glaciotectonically-deformed glaciofluvial sediments resulted from a progressive freezing of the basal water film that occurred on the side site of deformed structures. The water froze due to the drop in water pressure on the lee site of folds, which in turn led to the precipitation of calcite. The results of oxygen and carbon stable isotope studies (δ18O, δ13C) indicate limestone clasts embedded in the glaciofluvial deposits as the source of carbonates involved in the cementation process (δ18O from -6 to -3‰ V-PDB, δ13C – from -1.4 to +0.9‰ V-PDB). Two types of calcite cements were recognized in the studied conglomerate. Each of them is thought to be a record of different basal conditions during the ice-sheet advance. The precipitation of sparite cement took place during the early stages of freezing under open-system conditions (i.e. continuous flow of water within the film). Micrite cement which overlies the sparite one was precipitated during the final freezing under closed-system conditions (i.e. water flow in the film is dominated by locally produced water involved in the regelation sliding proces; Sharp et al., 1990). Moreover, it is known that micrite precipitates from water which is more supersaturated with respect to calcite than that from which sparite precipitates.A thin (up to 1 mm thick) manganese-rich layer was registered between the layers of sparite and micrite cements. The precipitation of calcite is characterized by δ18O and δ13C values ranging from -6.9 up to -6.2‰ (V-PDB) and from -9.0 up to -5.5‰ (V-PDB), respectively. No significant differences in the isotope notation between micrite and sparite were observed, which clearly indicates similar parameters of the host water. Mleczak, M., Woronko, B., Pisarska-Jamroży, M., Bujak, Ł., 2021. Permafrost as the main factor controlling the fluvial sedimentation style on glaciomarginal fans. Sedimentary Geology. 422, 105971. https://doi.org/10.1016/j.sedgeo.2021.105971Sharp M., Tison J.L., Fierens G., 1990. Geochemistry of Subglacial Calcites: Implications for the Hydrology of the Basal Water Film. Arctic and Alpine Research, 22, 2, 141-152.

We conducted year-round, monthly monitoring of the stable isotope composition of DIC and water in hypereutrophic Lake Kierskie, western Poland, along with isotope measures of calcite collected in sediment traps installed at 16 and 30 m water depth in the lake. Isotope data were supplemented by previously published data on physico-chemical variables in the lake water column. We sought to determine how carbon and oxygen isotopic disequilibria in calcite deposited in the lake’s laminated sediments vary seasonally, and what factors drive this variability. Deposition of calcite out of equilibrium with DIC and water was documented over the entire study period. For δ18O, the disequilibrium difference between successive months far exceeded the amplitude of the seasonal variability in the isotope composition of water. The biggest difference between the measured and calculated δ13Ccalcite and δ18Ocalcite values was observed during late autumn and winter sediment resuspension and redeposition (2.4‰ and 5.4‰, respectively). In the spring, δ13Ccalcite and δ18Ocalcite offsets from equilibria, 0.5‰ and 1.3‰, respectively, resulted from rapid precipitation of large calcite crystals. During summer, intense productivity and processes related to calcifying algae (“vital effects”) caused lower δ13C (0.5–1.8‰) and δ18O (2.8–2.9‰) in calcite. Differences between isotope values of calcite collected from the two water depths were small, and might have resulted from different settling velocities of small and large crystals, and/or preferential dissolution of smaller grains. We suggest that winter laminae should be excluded from isotope studies of varved sediments whenever possible, as they likely contain redeposited carbonate in which the isotope value is not indicative of conditions in the lake at the time of laminae formation. We also recommend supplementing isotope analysis of calcite in varved lake sediments with seasonally resolved analysis of carbonate content. It appears that major shifts in the proportion of carbonate deposited across seasons can cause notable changes in mean annual values of δ18Ocalcite and δ13Ccalcite, even if DIC and water isotopic compositions remain stable.

Accurate lake sediment-derived palaeoenvironmental reconstructions require in-depth knowledge on sediment record formation processes. In order to understand formation of laminated sediments in the eutrophic Lake Kierskie (western Poland) we conducted a year-round (November 2015–October 2016), monthly sediment trap study along with physico-chemical water properties, water transparency, hardness, alkalinity, nutrients and solute content, trophic state indices, and the phytoplankton assemblage monitoring. Sedimentation in Lake Kierskie primarily resulted from the activity of photosynthetic organisms. The maxima of biogenic silica accumulation were synchronous with the bloom of centric diatoms observed in March and April. These were followed by the most intensive precipitation of CaCO3 noted between mid-April and mid-June, that corroborated with the domination of Stephanodiscus hantzschii and small flagellate forms acting as nucleation sites for crystal formation. At the same time shift from the diatom-dominated assemblages to the communities composed of chlorophytes, cryptophytes, and dinoflagellates, the groups with cellulose external covering, resulted in decreased proportion between SiO2 and organic matter. CaCO3 precipitation continued in the summer months, however its amount decreased simultaneously with a drop in S. hantzschii biomass. The significant overall flux of biogenically mediated materials from epilimnion was promoted by eutrophic towards hypertrophic conditions in Lake Kierskie revealed by the trophic state indices. Mixing of the water column in autumn triggered resuspension and redeposition of the previously deposited sediments resulting in the second, after the early spring, maximum sediment flux. Minima of sediment accumulation were observed during the winter water stratification when the smallest particles sedimented from suspension. The sediment flux to the lake bottom recorded by us in a 1-year, monthly sediment trap study matches a sequence of pale, whitish lamina deposited during spring and summer, followed by dark, grayish or black lamina deposited in the autumn and winter, observed in the macroscopic investigation of the short (0.5 m) core from Lake Kierskie. Preservation of distinct laminations in the dimictic Lake Kierskie is supported by anoxic hypolimnion developed under the high supply of organic matter from epilimnion of this highly eutrophic lake.

Here we present results of high-resolution palaeoecological studies of the organic deposits accumulated in Lake Jaczno, located in the north-eastern Poland. Plant macrofossils and malacological analyses complimented by radiocarbon dating (AMS) were undertaken to reconstruct Early Holocene succession of the pioneer wetland plants and molluscs in the lake ecosystem. Numerous presence of charcoal pieces (>1 mm) and fungal remains (sclerotia) in the peat layer accumulated on the mineral ground document dry habitat what coincides with warm and dry climate conditions in the early Holocene recorded in this part of Europe. Change to lacustrine environment documented by accumulation of the carbonate gyttja on the highly decomposed peat layer took place ca. 10,500 cal yr BP. The current morphology of Lake Jaczno, in which several basins can be distinguished, suggests that different age of sediments accumulated at the bottom part at our sampling sites might result from different sizes of the buried dead ice blocks, and their heterochronous final melting. The first aquatic plants that appeared in Lake Jaczno were Chara sp., Ceratophyllum demersum and Nymphaea alba. The appearance of Cladium mariscus in Lake Jaczno ca. 9400 cal yr BP was synchronous with the substantial spread of this plant in this region which coincided with increased climate humidity. The first molluscan species that colonized the lake ecosystem were Gyraulus crista and Bithynia tentaculata, species living on macrophytes, and Valvata piscinalis, typical for habitats characterized by a thick layer of plant detritus.

The paper presents records of lithofacial succession in the sediments of the Bagno Staw alkaline fen (Western Polesie Lowland, Eastern Poland), documenting the phase of rapid morphogenetic transformations during LG/H in the Lublin chalkland. Environmental conditions responsible for the morphogenesis and evolution of the site (from a shallow periglacial lake to an alkaline fen) were reconstructed. A detailed geological survey in combination with the analysis of Cladocera assemblages revealed the presence of numerous palaeodepressions under the plain covered today by the alkaline fen, which were initially small shallow lakes with a well-developed phytolittoral zone. Geochemical data and the analysis of stable O and C isotopes indicated that these lakes were supplied by ascending waters. Karstic phenomena under periglacial conditions, including subsidence at the bottom of biogenic accumulation basins, played an important role in the transformation of this site. These changes were largely determined by the chronology and dynamics of permafrost degradation.

Although the contribution of current summer warming to the widespread drying of European peatlands is undeniable, summer temperature fluctuations alone are unable to explain all the hydrological shifts of these ecosystems. We aim to determine whether the current coupling of high summer temperatures and low water tables of peatlands in northern Poland is recent or has been stable over long timescales, and to infer the climatic context driving past relationships between temperature and peatland hydrology. We compare the previously published 4000-year long paleohydrological record from Kusowo bog with a new chironomid-based summer temperature record covering the last 4.5 ka from nearby (~7 km) Lake Spore. Although several simultaneous shifts in our hydrological and temperature reconstructions are evident on multi-decadal to centennial timescales, for instance during the peak cooling of the Migration Period or Little Ice Age (~1.4 and 0.4 cal ka, respectively), the records reveal mostly independent fluctuations. However, the relatively high uncertainty of our quantitative estimates suggests caution is warranted when inferring the strength of the relationship between the reconstructed variables at this temporal resolution. Howeverm, at centennial to millennial timescales, the relationship between the records is surprisingly strong. Overall, warmer summers (mean July temperature = 18.7 °C) before ~2.3 cal. ka corresponded well with lower ground water tables at Kusowo bog (mean = 11.2 cm), whereas cooler summers in the following period (mean = 17.4 °C) were accompanied by higher water tables (mean = 7.9 cm). Particularly wet bog conditions during the last ~0.7 ka were also the coldest. The finding that on long timescales the dring of Kusowo bog coincided with warming suggests a persistent regional climate pattern in which drought conditions change along with summer temperatures. If this millennial-scale pattern holds for the projected warming, further peatland drying can be expected in northern Poland.

In this study, we focus on the environmental changes recorded in the San River valley (Stubno–Naklo site, south-eastern Poland) at the beginning of the Holocene. This multi-proxy study for the first time in the region of the northern foreland of the Western Carpathians included quantitative thermal reconstruction based on Chironomidae and high-stratigraphic resolution of 14C AMS dating. We hypothesised that (i) climate events during the Early Holocene contributed to ecosystem turnovers via stimulating disturbances related to the river's fluvial activity and (ii) woodland and oxbow lake ecosystems became more resilient to flood disturbances along with the advance of forest succession on the floodplain. The results revealed that the response of ecosystems on the Early Holocene warming was strongly linked with the decrease in fluvial activity of the river. The reconstruction of the mean July temperature based on Chironomidae revealed the exceptionally high rate of warming during the period of ca. 11,490–11,460 cal. BP (at least 1 °C per decade) up to values > 2 °C than modern ones. During this period, the lake trophy and productivity started to increase with a simultaneous spread of Betula woodlands on the alluvial plain. The “Preboreal oscillation” cooling was dated at ca. 11,450–11,250 cal. BP. At that time, an increased climate instability led to a higher rate of extremal events such as flood at ca. 11,400–11,330 cal. BP, which probably led to the disruption of the Betula population. The development of riparian woodlands, initiated by the expansion of Ulmus from ca. 11,100 cal. BP, and further spread of Quercus and Fraxinus excelsior on the alluvial plain and lower river terraces increased plant transpiration and therefore limited the river runoff and its fluvial activity. This, together with the expansion of reed belt communities, probably limited the impact of floods on the oxbow lake. However, ca. 10,010–9880 cal. BP traces of higher fluvial activity, but of lower impact, were recorded.

We document the long-term development of a spring-fed fen assessing its sensivity to climate changes over the last ca. 4000 years. Our investigation is based on high-resolution, continuous plant macrofossil remains and mollusc records, complemented by pollen, geochemical analysis and radiocarbon dating of Valea Morii, located in the Feleac Hills (Transylvanian Depression) in NW Romania, Central Eastern Europe. Based on our palaeocological data we have distinguished three stages of wet habitat conditions: two stages between 4000 and 2450 cal yr BP and one in the last 800 cal yr BP, and one dry stage between ca. 2450 and 800 cal yr BP. These local habitat conditions appear to reasonably reflect regional climate characteristics. High-resolution analysis of two replicated cores documented a mostly comparable pattern of local plant and mollusc succession, and stable isotope values from ca. 500 cal yr BP. The appearance of C. mariscus during the last two centuries may be related to increased wetness and associated active CaCO3 precipitation, which allowed this plant to colonise the spring-fed fen studied. However, it can be not excluded that the occurrence and spread of a Cladium mariscus population at this site during the last two centuries might have been partly favoured by the warming of the climate after the Little Ice Age. The potential of carbonate oxygen stable isotope values as an indicator of major trends in climatic change, both temperature and humidity, in mountain spring-fed fen deposits is shown. Carbon isotopes in the carbonates were found to be useful in reconstruction of changes in vegetation, soil development and the dissolution of bedrock carbonates, primarily as a reaction to changes in climate humidity.

This article presents the first multi-proxy study of palaeoecosystem changes during the Late Weichselian and Early Holocene in western Ukraine. The site is a former oxbow lake situated in the Dniester River valley (western Ukraine). We hypothesised that this area may have been one of the nuclei for the Holocene expansion of elm (Ulmus), a primary arboreal taxon in riparian woodlands, in the Central and Eastern European lowlands. Our study was undertaken on a profile encompassing the period ca. 12,900–9880 cal. BP. We applied selected palaeobotanical, palaeozoological and geochemical analyses. During the Younger Dryas the area was dominated by well-developed Pinus sylvestris-Betula woodlands. Drier habitats were overgrown by Juniperus shrublands and steppe communities. Patches of tundra with Betula nana were also present. Ulmus started to spread on the lower river terraces before ca. 11,840 cal. BP i.e., during the late Younger Dryas, which suggests this area as a nucleus for its Holocene expansion. A chironomid-based reconstructed mean July temperature (MJT) of 15–17 °C is suggested during the Younger Dryas. The main Ulmus expansion started ca. 11,160 cal. BP and its optimum in local woodlands lasted until ca. 10,340 cal. BP, when Pinus sylvestris rapidly expanded. The reconstructed MJT varied between 18 and 21 °C during the Ulmus optimum; however, it rapidly declined to 16 °C around ca. 10,800 cal. BP. Fire activity increased before ca. 10,870 cal. BP, concurrent with the climate warming at the Younger Dryas-Holocene transition, but did not affect the population of Ulmus, a taxon intolerant of fires. Wildfires probably affected patches of steppe vegetation and Pinus sylvestris-Betula woodlands occupying higher elevations of the valley and watersheds. However, changes in the fire activity may have stimulated Ulmus retreat at ca. 10,340 cal. BP.

Oxygen (δ18O) and carbon (δ13C) stable isotope analyses are among the standard methods applied in the studies of past environment, including climate. In lacustrine sediments, δ18O and δ13C values can be measured in various carbonates including charophyte encrustations. Application of the stable isotope record of lacustrine carbonates requires knowledge about the possibilities and limitations of the method. Thus, this study presents the oxygen stable isotope composition of carbonate encrustations precipitated by modern charophytes (δ18OCARB) and of ambient waters (δ18OWATER). The study objects were widely distributed and morphologically different charophyte species, large and branchy Chara tomentosa L. and small and slender Chara globularis Thuill. Each species was studied in five lakes located in western Poland, at three sites per lake. The study demonstrated that δ18OCARB values were similar for the two charophyte species and were lake-dependent. δ18OCARB and δ18OWATER relationships were also similar for the studied charophytes with carbonate encrustations 18O-depleted compared to ambient waters. The shift of mean δ18O values between C. tomentosa and C. globularis encrustations and ambient waters, 2‰ and 3.2‰, respectively, was evidenced in all studied lakes which may indicate potential applicability of δ18OCARB of the two species in paleolimnological studies.

This study focuses on the inter- and intra-specific variability in δ13C and δ18O values of shells and opercula of gastropods sampled live from the littoral zone of Lake Lednica, western Poland. The δ13C and δ18O values were measured in individual opercula of Bithynia tentaculata and in shells of Bithynia tentaculata, Gyraulus albus, Gyraulus crista, Lymnaea sp., Physa fontinalis, Radix auricularia, Theodoxus fluviatilis and Valvata cristata. The gastropods selected for the study are among the species most commonly found in European Quaternary lacustrine sediments. The carbon isotope composition of the gastropod shells was species-specific and the same order of species from the most to the least13C-depleted was observed at all sites sampled. Differences in shell δ13C values between species were similar at all sampling sites, thus the factors influencing shell isotopic composition were interpreted as species-specific. The δ18O values of shells were similar in all the species investigated. Significant intra-specific variability in shell δ13C and δ18O values was observed not only within the populations of Lake Lednica, which can be explained by heterogeneity of δ13C DIC, δ18O water and water temperature between the sites where macrophytes with snails attached were sampled, but also between individuals sampled from restricted areas of the lake’s bottom. The latter points to the importance of factors related to the ontogeny of individual gastropods.

Mountainous areas of Central and Eastern Europe were crucial for the survival of temperate deciduous trees during the Weichselian glaciation. The distribution of these tree refugia was one of the key factors for the migration and composition of temperate forests during the Late Glacial and Holocene. In this article, a palaeoenvironmental reconstruction from the landslide palaeolake located within a lower montane zone in the northern part of the Western Carpathians (Beskid Makowski Mountains) is presented. A multiproxy approach, involving several biotic proxies, combined with organic carbon and nitrogen content and their isotopic ratio, supported by high stratigraphic accelerator mass spectrometry (AMS) 14 C dating was applied for the reconstruction of vegetation changes and their influence on the small lake ecosystem. The results revealed that forests dominated by Pinus sylvestris , Betula , and Picea abies , in which Pinus cembra and Larix decidua were an admixture, were present from at least ca. 11,240 cal BP. From ca. 11,130 cal BP, elm ( Ulmus ) started to spread, and ca. 70 (± 30) years later, it probably has become a prominent constituent of the local forests. This process was coincident with an increased fire activity and the retreat of P. cembra and L. decidua . The early spread of Ulmus in the lower mountainous forest ecosystem is an indirect evidence of the presence of its Late Glacial refugia in the Western Carpathians. The lake, functioning during that time, was characterised by high sedimentation rate (0.16–0.2 cm year − 1 ), low primary productivity, low Cladocera diversity mainly dominated by Chydorus sphaericus complex, and low Chironomidae concentration. The spread of aquatic vegetation, among them Potamogeton obtusifolius and Potamogeton friesii , in the lake was simultaneous to Ulmus expansion and the constant presence of P. abies macrofossils.

Here, for the first time in SE Poland, we document the long-term development of a rich fen and assess its sensitivity to climate change and human impacts over the last ca. 3500 years. Our results are based on a high-resolution, continuous plant macrofossil remains, mollusc and pollen record, complemented by geochemical, mineral magnetic and physical characterisation, and radiocarbon dating from Bagno Serebryskie rich fen located in SE Poland. Based on the palaeoecological data we distinguished five stages of wet habitat conditions: 5000–3300, 2800–2150, 1600–1100, 750–230, 150–10 cal yr BP and five dry periods at ca. 3300–2800, 2150–1600, 1100–750, 230–150, 10 to − 64 cal yr BP. The pollen and geochemistry records, particularly Pb, show that the first human activity in the study area occurred ca. 3200 cal yr BP and increased markedly from 500 cal yr BP affecting local plant development including the population size of Cladium mariscus. Our study has shown that despite human impact (drainage, fire), Bagno Serebryskie peatland has hosted rare, presently protected species, such as Cladium mariscus for hundreds of years. We conclude that, in common with ombrotrophic bogs, rich fen ecosystems can provide a reliable source of palaeoclimatic and palaeohydrological data. Our study also shows that a large peatland (376 ha) can be as sensitive a palaeohydrological archive as smaller mires.

The Wietrzychowice Cultural Park protects one of the last preserved megalithic barrows of the Funnel Beaker Culture people at the Kuyavia Lakeland (Central Poland). Archaeological excavations of the lake palaeolittoral zone were conducted on the nearby Karania Lake shore. Numerous Mesolithic and Neolithic remains were excavated including: flint artefacts, potsherds, arrowheads, and mammal bones with traces of human processing. The SM9G2 core from the miey site covers gyttias and peats with the Holocene history of Karania Lake. The age-depth model is based on 3 AMS and 3 LSC radiocarbon dates as well as cultural remains. The bottom section of the core (275-190cm b.g.l.) includes the record of the early to mid-Holocene layers that fall on the Mesolithic and Neolithic in the region. The multi-proxy study (geochemistry, plant macrofossils, pollen, Mollusca, Cladocera and Chironomidae analyses) were conducted on the Mesolithic-Neolithic section of the core. Additionally, Chironomidae subfossil analysis was conducted on the SM1 core from another part of the Karania Lake shore zone, documenting the mid-Holocene age of the lake littoral shore development.

The stable carbon isotope composition of the carbonate encrustations (δ13CCARB), organic matter (δ13CORG) and the dissolved inorganic carbon (δ13CDIC) in the ambient lake waters were analysed for two common but morphologically different and, thus, representing different growth forms of Chara species. We hypothesized that the relationships between δ13CCARB, δ13CORG and δ13CDIC are species specific and related to the different growth forms of the studied charophytes. For each species (Chara tomentosa and Chara globularis), 10 individuals and water samples from above the macrophytes were collected in five lakes at three sites per lake in mid-summer. Opposing shifts were found between δ13CCARB and δ13CDIC values with 13C enrichment in C. tomentosa and 13C depletion in C. globularis. In addition, C. globularis exhibited more negative values of δ13CORG than C. tomentosa, even under similar conditions. The δ13CCARB and δ13CORG values were positively correlated in both species, but δ13CCARB and δ13CDIC as well as δ13CORG and δ13CDIC were positively correlated in C. tomentosa only. The differences found result from the different proportions between 13C and 12C in DIC used as a CO2 source for photosynthesis, which is linked to the different growth forms represented by the two studied charophytes and, thus, are species specific as we hypothesized.

Many regions around the world experienced abrupt climate change with far-reaching societal and environmental effects at ca. 4.2 cal. ka BP. As one of the most distinct climatic events of the last 11.7 ka, it has been used to establish the formal boundary between the mid- and late-Holocene. Although the 4.2 ka event was not pronounced in East-Central Europe, its exact impact on the area has yet to be evaluated. The aim of this paper is twofold: (1) to reconstruct the functioning of the selected lake and terrestrial ecosystems from northern Poland around the time of the 4.2 ka event, and (2) to disentangle the drivers of the recorded environmental changes (local factors vs. climate impact). We studied the sedimentary record of Lake Spore, focusing on the period between 3.8 and 4.5 cal. ka BP using numerous biotic and abiotic proxies, such as chironomids, cladocerans, pollen and spores, δ13Corg, δ15Norg, δ18Ocarb, δ13Ccarb, TOC/N, Fe, S, LOI550, and LOI950. The chironomid-derived reconstruction of mean July air temperature did not change during the 4.2 ka event. Pollen accumulation rate (PAR) data showed lower pollen production of some tree taxa during the period 4.0–4.25 cal. ka BP that is consistent with low PARs recorded for the corresponding period in the sediments of nearby (~75 km) Lake Suminko. This change might have occurred due to either regional-scale forest disturbance or cooler winters resulting from an exceptionally strong Siberian High during the 4.2 ka event. Distinct peaks of Fe and δ13Ccarb at 4.2 cal. ka BP likely record a pulse of podzolization. Although soil transformation processes were common in East-Central Europe after ca. 5 cal. ka BP due to general climate cooling, they could have been enhanced at Lake Spore during the 4.2 ka event, if winters were more severe. The δ13Corg, δ15Norg, TOC/N and δ18Ocarb records point to a water level rise after 4.2 cal. ka BP that most likely resulted from soil transformation in the catchment, not a change in effective precipitation. The composition of the terrestrial vegetation and the lake fauna and flora remained largely unaffected by the 4.2 ka event.

This study aimed to: (1) investigate intra-sample variability in the stable isotope composition (δ13C and δ18O values) measured in several individual mollusc shells; and (2) determine the optimum number of individual mollusc shells required to obtain stable isotope values representative of the mean climate signal for a sediment sample. Seven hundred and six gastropod shells were analysed, representing eight species. These eight species were most abundant and consistently present in the sediment sequence of the Paddenluch outcrop, Brandenburg, northeast Germany. Significant differences between minimum and maximum δ13C and δ18O values of the shells were recorded within all sediment samples and for all analysed species. Within the sediment samples, the greatest mean variability in both δ13C and δ18O values was found for Hippeutis complanatus, 5.84 and 5.23 ‰, respectively. The greatest intra-specific variability in C and O isotope values within individual sediment samples, however, was 10.2 and 6.8 ‰, respectively. Significant differences between minimum and maximum δ13C and δ18O values of individual mollusc shells within the same sediment sample are probably the result of population isotope variability, variations in species life span, thickness of the sediment sample, sediment accumulation rate, and environmental fluctuations during the time span when the sediment was deposited. Shells were randomly selected to determine the optimum number of shells necessary to obtain stable isotope values that are representative of the mean climate signal, from a 1-cm sample of sediment. For each layer of the Paddenluch sediment sequence, 15 or more shells (N ≥ 15) was the required sample size to provide representative isotope values and yield a reliable mean isotope value. Sample sizes with fewer shells displayed more variable mean δ13C and δ18O values. Stable isotope composition of the analyzed molluscs was species-specific, with differences in mean δ13C and δ18O values of 2.5 and 3 ‰, respectively. This illustrates the need to use mono-specific samples throughout a sediment sequence to generate reliable data.

The study reports and discusses the differences in δ 13 C and δ 18 O values of shells between several species of freshwater snails. Shells were derived from sediment samples collected from depths of 0.5, 1, 2 and 3 m along transects in two shallow eutrophic lakes located in mid-western Poland. Mean δ 13 C values of the shells ranged between −7.5 and −3.8‰ in Lake Jaroslawieckie and between −8.1 and −5.2‰ in Lake Rosnowskie Duze, whereas mean δ 18 O values ranged between −2.2 and −0.2‰ and between −2.2 and 0.4‰ respectively in the studied lakes. A similar order of species in terms of shell isotope values, from least to most 13 C and 18 O-depleted was observed in both lakes and seems to indicate constancy of the factors controlling the stable isotope compositions of snail shells. We postulate that the nearly 4‰ difference in the mean carbon stable isotope values between the species was primarily controlled by the amount of metabolic carbon incorporated into the shells and the δ 13 C values of the snail food. Different growth cessation temperatures and microhabitats of the species studied result in temporally and spatially varied DIC δ 13 C values, water δ 18 O values and water temperature of shell precipitation, and may thus differentiate the δ 13 C and δ 18 O values of shells. The range of δ 13 C and δ 18 O values of individual shells from a sediment sample (mean 2.35 and 2.15‰, respectively) is interpreted as reflecting an intraspecific variability of isotope compositions in shells from a population and changes of the ambient conditions during the accumulation of the sediment layer. The species-specificity and intraspecific variability in C and O isotopic compositions of shells allow concluding that in palaeolimnological studies, stable isotope analyses should be performed on a set of mono-specific shells representing mean isotope compositions of the species for the interval studied rather than single shells or multispecific bulk shell material.

In this study we investigated the relationships between charophyte abundance and water chemistry in four well vegetated lakes in western Poland differing in morphometry, catchment basin characteristics, and intensity of human pressure. Species composition and abundance (expressed as cover and, additionally, as PVI values, defined as per cent volume of water infested by plants) of vegetation patches dominated by Chara tomentosa L. were determined along with water physicochemical characteristics at nine permanent study sites monthly from spring through autumn. We hypothesised that the species composition of C. tomentosa meadows is lake-specific whereas the abundant growth is the cause rather than a response to water quality of the studied lakes. C. tomentosa formed dense swards in every studied vegetation patch, irrespective of water depth, with negligible contributions of vascular plants to species richness and abundance. Although 15 macrophyte species were identified in the studied meadows, including eight charophytes, C. tomentosa dominated throughout the growing season. Heterogeneity observed in the species composition and cover was site-specific rather than related to physicochemical differences among the lakes. PVI values were positively correlated with water temperature and pH, and negatively correlated with water conductivity, hardness and Ca2+ concentrations. The results indicate a preference for high water clarity by most charophyte species found in the studied patches and highlight the possible influence of charophyte meadows on water quality, primarily on solute content, hardness and, thereby, as a positive feedback, on water clarity.

This article presents potential errors related to the construction of absolute chronologies for Late Glacial and Early Holocene sediments accumulated in oxbow lakes in Central Europe and their influence on palaeoecological reconstruction. Our study is based on two sediment cores: (i) from the San River (Stubno-Naklo site in south-eastern Poland; S-N) and (ii) from the Dniester River (Luka site in western Ukraine) valleys. Accelerator mass spectrometry (AMS) 14C dating was performed on terrestrial plant macrofossils from each site to produce Bayesian age–depth models and to calculate sedimentation rates (SRs). The SR in both sites was characterised by high variability reflecting the developmental stage of oxbow lake. The highest SR values (1.18–1.23 cm yr-1) were identified at the S-N site at the beginning of the Holocene (ca. 11,550–11,470 cal. BP) and related to enhanced overbank deposition. The lowest SR values (0.01–0.02 cm yr-1) were identified in the transitional layer between the Younger Dryas and the Preboreal chronozone (ca. 11,810–11,160 cal. BP) in the Luka profile; this may have been related to the sedimentary gap(s) caused by falls in the water table and/or temporary desiccation of the water body. Moreover, our study revealed the presence of three distinctly aged AMS 14C dates in the Younger Dryas section of the Luka profile. These radiocarbon inversions were completely undetected by pollen analysis, which indicated the domination of Pinus and Betula without any significant fluctuations throughout the entire subsection. The presence of such ‘cryptic’ insertions of older material could lead to erroneous palaeoenvironmental reconstruction. Similarly the S-N site revealed anomalously ‘aged’ dates which were also difficult to detect by pollen analysis.

High-resolution biological proxies (pollen, macrofossils, Cladocera and diatoms), geochemical data (μ-XRF element scans, TOC, C/N ratios, δ 18 O carb and δ 13 C org values) and a robust chronology based on varve counting, AMS 14 C dating and tephrochronology were applied to reconstruct lake system responses to rapid climatic and environmental changes of the Trzechowskie palaeolake (TRZ; Northern Poland) during the late Allerod – Younger Dryas (YD) transition. Palaeoecological and geochemical data at 5–15 years temporal resolution allowed tracing the dynamics of short-term shifts of the ecosystem triggered by abrupt climate change. The robust age control together with the high-resolution sampling allowed the detection of leads and lags between different proxies to the climate shift at the Allerod-Younger Dryas transition. Our results indicate (1) a water level decrease and an increase in wind activities during the late Allerod and the Allerod-YD transition, which caused intensified erosion in the catchment, (2) a two-decades delayed vegetation response in comparison to the lake depositional system. Comparison with the Lake Meerfelder Maar record revealed slightly different vegetation responses of the Trzechowskie palaeolake at the YD onset.

This paper presents a history of the vegetation in Lake Purwin (NE Poland) and its catchment along with water level changes for the last 8600 cal. BP. The reconstructions are based on a high-resolution plant macroremains analysis and the stable isotope record in authigenic carbonates, a fine fraction that is precipitated within the epilimnion of the lake. The stable isotope records suggest that the lake had throughflow during the Holocene and that isotope data can therefore be used in palaeoclimatic reconstructions. The δ18O values record the thermal maximum of the Holocene and the subsequent cooling of the upper Holocene. Water level changes and the history of the lake's productivity are both recorded in the δ13C values. A chronology is established using radiocarbon dating of terrestrial plant macrofossils. The vegetation and water levels in Lake Purwin reflect regional climate changes. The combination of the lithology along the sedimentary sequence, the results of the plant macroremains analysis and the isotope data allowed several alternating periods of high (8600–7300, 6500–5200, 4400–3500, and 3000–950 cal. BP) and low (7300–6500, 5200–4400, 3500–3000 and 950 to −59 cal. BP) water stands to be distinguished in Lake Purwin. Low water levels are indicated by sediments that are enriched in coarse plant detritus, seeds of Rubus ideaus, fruits of Uritca dioica and more macroremains of Alnus glutinosa and rushes.

Stable carbon and oxygen isotope studies are among the major proxies in investigations of recent and ancient freshwater environments. Mollusc shells are one the most frequently studied carbonates. In the present paper, stable carbon and oxygen isotope compositions of Dreissena polymorpha (Pallas) shells, regarded as the most aggressive freshwater invader worldwide, is compared with the stable isotope composition of ambient water. Macrophytes with modern D. polymorpha shells attached were sampled twice, in June and August 2011, from four transects established within the littoral of Lake Lednica (western Poland). The macrophytes were sampled between 0.5 and 7 m of depth at each site from the restricted area of the lake bottom. In order to avoid the influence of ontogeny on the results obtained the stable isotope compositions of shells of equal or nearly equal sizes within one population were compared. A significant spread was observed in the stable isotope signatures in the D. polymorpha shells, particularly in the δ13C values derived from one population. The spread in δ13C and δ18O values was observed in both juvenile and adult shells; however, it increased with age. It is suggested that stable isotope investigations of D. polymorpha shells should not be performed on single shells, as the isotope values will not be representative of the coeval individuals within population. While the shells of D. polymorpha were close to oxygen isotope equilibrium with the ambient water, they were characterised by a 1.5–2 ‰ depletion in 13C relative to δ13CDIC. Both the spread in δ13C values in the shells and the 13C depletion observed in the shells are interpreted as resulting from a strong metabolic influence on shell composition. Because the offset observed between dissolved inorganic carbon (DIC) and shells is relatively constant, the stable carbon isotope composition of D. polymorpha shells may reflect environmental conditions and thus may be used as a palaeolimnological proxy.

A significant portion of calcium carbonate is deposited in lake sediments as a result of biological processes related to the photosynthetic activity of phytoplankton in the pelagic realm and, in addition, macrophytes in the littoral zone. Lake Wigry, one of the largest lakes in Poland (north-east Poland), is characterized by: (i) carbonate sediments with a CaCO3 content exceeding 80% within the littoral zone; and (ii) large areas of submerged vegetation dominated by charophytes (macroscopic green algae, Characeae family). It is claimed that charophytes are highly effective in utilizing HCO3− and forming thick CaCO3 encrustations. Thus, this study was aimed at evaluating the CaCO3 production by dense Chara stands overgrowing the lake bottom reaching a depth of 4 m. In late July 2009, the fresh and dry mass of plants, the percentage contribution of calcium carbonate and the production of CaCO3 per 1 m2 were investigated along three transects at three depths (1 m, 2 m and 3 m, with each sample area equal to 0·0625 m2) per transect. The composition and structure of phytoplankton and the physico-chemical properties of the water analysed in both the littoral and pelagic zones served as the environmental background and demonstrated moderately low fertility in the lake. The greatest dry plant mass exceeded 1000 g m−2 and CaCO3 encrustations constituted from 59% to over 76% of the charophyte dry weight. Thus, the maximum and average values of carbonates precipitated by charophytes were 685·5 and 438 g m−2, respectively, which exceeded previously reported results. A correlation of carbonate production with the depth of Chara stands was detected, and intermediate depths offered the most favourable conditions for carbonate precipitation (589 g m−2 on average). As precipitated carbonates are ultimately stored in bottom deposits, the results highlight the significance of charophytes in lacustrine CaCO3 sedimentation.

This paper presents a comprehensive palaeoenvironmental data set from Lake Skrzynka, northern Poland. A sediment core from the lake was investigated to reconstruct Lateglacial and Holocene environmental changes in northern Poland using a combination of palynology and stable carbon and oxygen isotope studies of carbonates and sediment geochemistry. The undisturbed sedimentation in Lake Skrzynka continues from the Allerod to the present. Our data suggest the persistence of dead ice in the Lake Skrzynka basin up to the Allerod. The sedimentary record of the lake reflects a considerable difference between the Lateglacial/early Holocene and the middle/late Holocene in terms of environmental conditions. The Lateglacial was characterized by rapid environmental changes, while climatic conditions throughout the Holocene were relatively stable. The trophic state of the lake was strictly dependent on climatically controlled vegetation changes and erosion tendencies in the vicinity of Lake Skrzynka. During the Lateglacial and early Holocene, as a result of predominantly open plant communities and enhanced nutrient export from the watershed, Lake Skrzynka experienced an increased trophy. The stabilization of forest cover and reduced input of nutrients resulted in the establishment of oligotrophic conditions in the lake in the early Boreal. During the late Subatlantic, the lake became eutrophic as a result of human disturbance of the local hydrological balance. The postglacial history of Lake Skrzynka can be regarded as representative of small, alkaline, through-flow lakes in temperate climates.

Stable isotope composition (δ13C and δ18O) was analysed in mineral incrustation of Chara rudis and surrounding waters. This macroalga forms dense and extensive charophyte meadows and may significantly contribute to the calcium carbonate precipitation and deposition of marl lake sediments. The study aimed to find out if charophyte calcium carbonate was precipitated in an isotopic equilibrium with lake water and if the precipitation was related to the environmental conditions. Two apical internodes of 10 individuals of C. rudis were collected monthly between June and late October 2008 at three permanent study sites (1.0 m, 1.5 m and 2.0 m deep) in a small (15.1 ha) and shallow (mean depth: 4.3 m) mid-forest lake with extensively developed charophyte meadows (Lake Jasne, mid-Western Poland). Basic physical–chemical analyses were performed at each study site, and water samples for further laboratory determinations, including stable isotope analyses, were collected from the above searched C. rudis stands and, simultaneously, at three comparative sites in the macrophyte-free pelagial. The difference in δ13C between incrustation and water from above C. rudis exceeded 2‰ V-PDB at each site. In the case of δ18O, it exceeded 2‰ between July and September. Accordingly, it is postulated that calcium carbonate was not precipitated in an isotopic equilibrium with lake water. Incrustation was enriched in heavier carbon isotope, 13C, and water was enriched in 18O. δ13C of incrustation and DIC were positively correlated, whereas negative relation was found between δ18O of incrustation and water. Several dependencies were found with water chemistry above the plants. The content of mineral incrustation in Chara dry weight had negative influence on the δ18O but not on the δ13C. Community depth, structure and PVI had no effect. No significant differences appeared between isotope composition in the pelagic zone and Chara stands.

Late Weichselian and early Holocene climatic and environmental changes are inferred from stable carbon and oxygen isotope records obtained on bulk and biogenic carbonates from the sediment sequence of Lake Lednica, western Poland. Along with sediment and pollen stratigraphic data, a wide range of carbonate components occurring in the sediments was analysed for delta C-13 and delta O-18, including shells of several gastropod species and the bivalve genus Pisidium, carapaces of the ostracod subfamily Candoninae and oogonia of the aquatic macrophyte genus Chara. The development of catchment soils and the onset of authigenic carbonate production in response to the climatic amelioration during the Late Weichselian are clearly reflected by rising carbonate content, distinct isotopic shifts in bulk carbonates and decreasing delta C-13 values of bulk organic matter in the sediments. The GI-1/GS-1 (the Bolling-Allerod Interstadial complex/Younger Dryas Stadial) and the GS-1/Preboreal transitions are marked by significant shifts in delta O-18 values of 2-3 parts per thousand, as well as by distinct changes in carbonate content, indicative of a decrease and a subsequent increase in mean annual temperature. Corresponding delta C-13 records reflect primarily changes in aquatic productivity, with favourable conditions for phytoplankton and macrophytes during GI-1 and the Preboreal resulting in persistent C-13 enrichment. The Younger Dryas Stadial is characterised by depletions in C-13 and O-18, with indications of a climatic tripartition. Consistent offsets in delta C-13 and delta O-18 between records obtained on specific carbonate components reflect vital effects in combination with seasonal characteristics and habitat preferences of the respective carbonate-precipitating biota. Largely parallel first-order variations in delta C-13 and delta O-18 of the different carbonate components demonstrate that individual isotope records may provide important palaeoclimatic information, although more detailed reconstructions can be obtained from multi-component analysis. Copyright (C) 2009 John Wiley & Sons, Ltd.

The aim of this study was to better understand the relations between carbon and oxygen stable isotope values of ambient water, mollusc shells, macrophytes and their carbonate encrustations, commonly used in palaeolimnological studies. Water, molluscs and macrophytes were sampled from the littoral zone in Lake Lednica, NW Poland. The influence of carbon species assimilated during photosynthesis and the net intensity of photosynthesis resulting from the size of charophyte species and the density of their stands were postulated to be the most important factors causing the species-specific δ13C values of charophyte thalli and encrustations. It was suggested that photosynthetic activity of charophytes affected not only the δ13C values of charophyte encrustations but also mollusc shells by changing δ13C values of DIC within charophyte stands. In addition, incorporation of metabolic carbon into the shell was proposed as the main cause of both the 13C depletion of mollusc shells relative to δ13C values of DIC and the species-specific δ13C values of shells. Mollusc shells were precipitated at the isotope equilibrium or close to the equilibrium with δ18O values of lake water. Charophyte encrustations were found to be 18O depleted due to the kinetic isotope effects during intense photosynthesis and thus fast precipitation of the calcite.