Browsing by Author "Szczuciński, Witold"
Now showing 1 - 20 of 22
Results Per Page
- Item26 December 2004 tsunami deposits left in areas of various tsunami runup in coastal zone of Thailand(TERRAPUB, 2012-10) Szczuciński, Witold; Rachlewicz, Grzegorz; Chaimanee, Niran; Saisuttichai, Darunee; Tepsuwan, Thawatchai; Lorenc, StanisławThe tsunami deposits left by the 26 December 2004 tsunami in the coastal zone of Thailand were studied within two months of the event and before any significant postdepositional changes could occur. The sediment structure and texture (grain size), as well as its thickness and spatial distribution, were documented for the tsunami deposits in 12 shore-perpendicular transects from areas of various tsunami runup and wave heights. The tsunami deposits were as thick as 0.4 m and were located as far as 1.5 km inland. They were composed mostly of poorly sorted sand and often consisted of one to four normally graded, massive or laminated layers. The deposits generally became finer in the landward direction; however, landward thinning trend of the deposits is not clear, and the maximum accumulation often is not located close to the shoreline but rather is further inland. In comparable coastal environments with similar available sediment sources the tsunami size (represented as the tsunami runup height) is reflected in the resulting deposits. Larger tsunamis are associated with deposits that are thicker, have a maximum accumulation located farther inland, include a finer sediment fraction (likely from deeper offshore areas) and frequently are composed of normally graded layers.
- ItemCoexistence of Lobelia dortmanna and Cladium mariscus, an ecological and paleobotanical study(2021) Milecka, Krystyna; Kowalewski, Grzegorz; Lewandowska, Agnieszka; Szczuciński, Witold; Goslar, TomaszLobelia dortmanna L. (Lobeliaceae family) is an indicator species that is predominantly found in oligotrophic and acidic lakes. They are mainly distributed in northwestern Europe. Their occurrence in Poland is highly threatened by the increasing grade of human activity and environmental eutrophication; however, new sites of Lobelia were discovered in the last few decades, for example, in Lake Krzywce Wielkie situated in Bory Tucholskie National Park (BTNP), Poland. The existence of Lobelia in this lake was unexpected because Cladium mariscus was also found in the lake. Cladium has different ecological demands and is regarded as a species typical of calcareous habitats where calcium is found in abundance in the substrate. To explain the coexistence of both species in Krzywce Wielkie, pollen analysis of organic sediments was performed for four short cores collected from the littoral zone of the lake and for one long deep-water core. Additionally, macrofossil analysis was done for all the short cores. Pollen analysis revealed the existence of Cladium from the early Holocene period up to the present time. Pollen and seeds of Lobelia were found to be present since the beginning of the 20th century. Development of L. dortmanna and Myriophyllum alterniflorum populations and a decrease in the number of aquatic macrophytes in the eutrophic water indicate oligotrophication of water. This process started following the construction of drainage canal and the consequent water level decrease. This situation can be attributed to the abandonment of the agricultural areas adjoining the lake, which causes a decrease in the inflow of nutrients into the lake. Development of pine forest and establishment of BTNP enabled the protection and conservation of the surrounding catchment areas, thus restricting the potential eutrophication of the habitats.
- ItemControls on coastal flooding in the southern Baltic Sea revealed from the late Holocene sedimentary records(2022-06-11) Leszczyńska, Karolina; Stattegger, Karl; Moskalewicz, Damian; Jagodziński, Robert; Kokociński, Mikołaj; Niedzielski, Przemysław; Szczuciński, WitoldClimate change and related sea-level rise pose significant threats to lowland coasts. However, the role of key controlling factors responsible for the frequency and landward extent of extreme storm surges is not yet fully understood. Here, we present a high-resolution sedimentary record of extreme storm surge flooding from the non-tidal southern Baltic Sea, spanning two periods: 3.6–2.9 ka BP and 0.7 ka BP until present. Sediments from coastal wetland, including sandy event layers, were analyzed by sedimentological (grain size, loss-on-ignition, micromorphology), geochronological (14C), geochemical (XRF), mineralogical (heavy minerals) and micropaleontological (diatoms) methods. The results show that both periods were characterized by high-frequency of storm surge flooding, in order of 1.3–4.2 events per century. These periods correlate with phases of enhanced storminess in northwest Europe and took place during both rising and fluctuating sea levels. The study shows that the frequency and landward extent of coastal inundation, largely depended on the development of natural barriers (e.g. beach ridges and aeolian foredunes). Thus, in the context of the future coastal storm-surge hazard, the protection of existing coastal barriers and their morphology is essential.
- ItemCryoconite – From minerals and organic matter to bioengineered sediments on glacier's surfaces(Elsevier, 2022) Rozwalak, Piotr; Podkowa, Paweł; Buda, Jakub; Niedzielski, Przemysław; Kawecki, Szymon; Ambrosini, Roberto; Azzoni, Roberto S.; Baccolo, Giovanni; Ceballos, Jorge L.; Cook, Joseph; Di Mauro, Biagio; Ficetola, Gentile Francesco; Franzetti, Andrea; Ignatiuk, Dariusz; Klimaszyk, Piotr; Łokas, Edyta; Ono, Masato; Parnikoza, Ivan; Pietryka, Mirosława; Pittino, Francesca; Poniecka, Ewa; Porazinska, Dorota L.; Richter, Dorota; Schmidt, Steven K.; Sommers, Pacifica; Souza-Kasprzyk, Juliana; Stibal, Marek; Szczuciński, Witold; Uetake, Jun; Wejnerowski, Łukasz; Yde, Jacob C.; Takeuchi, Nozomu; Zawierucha, KrzysztofCryoconite is a mixture of mineral and organic material covering glacial ice, playing important roles in biogeochemical cycles and lowering the albedo of a glacier surface. Understanding the differences in structure of cryoconite across the globe can be important in recognizing past and future changes in supraglacial environments and ice-organisms-minerals interactions. Despite the worldwide distribution and over a century of studies, the basic characteristics of cryoconite, including its forms and geochemistry, remain poorly studied. The major purpose of our study is the presentation and description of morphological diversity, chemical and photoautotrophs composition, and organic matter content of cryoconite sampled from 33 polar and mountain glaciers around the globe. Observations revealed that cryoconite is represented by various morphologies including loose and granular forms. Granular cryoconite includes smooth, rounded, or irregularly shaped forms; with some having their surfaces covered by cyanobacteria filaments. The occurrence of granules increased with the organic matter content in cryoconite. Moreover, a major driver of cryoconite colouring was the concentration of organic matter and its interplay with minerals. The structure of cyanobacteria and algae communities in cryoconite differs between glaciers, but representatives of cyanobacteria families Pseudanabaenaceae and Phormidiaceae, and algae familiesMesotaeniaceae and Ulotrichaceae were the most common. The most of detected cyanobacterial taxa are known to produce polymeric substances (EPS) that may cement granules. Organic matter content in cryoconite varied between glaciers, ranging from 1% to 38%. The geochemistry of all the investigated samples reflected local sediment sources, except of highly concentrated Pb and Hg in cryoconite collected from Europeanglaciers near indus-rialized regions, corroborating cryoconite as element-specific collector and potential environmental indicator of anthropogenic activity. Our work supports a notion that cryoconite may be more than just simple sediment and instead exhibits complex structure with relevance for biodiversity and the functioning of glacial ecosystems.
- ItemDrift-dependent changes in iceberg size-frequency distributions(Nature Publishing Group, 2017-11) Kirkham, James D.; Rosser, Nick J.; Wainwright, John; Vann Jones, Emma C.; Dunning, Stuart A.; Lane, Victoria S.; Hawthorn, David E.; Strzelecki, Mateusz C.; Szczuciński, WitoldAlthough the size-frequency distributions of icebergs can provide insight into how they disintegrate, our understanding of this process is incomplete. Fundamentally, there is a discrepancy between iceberg power-law size-frequency distributions observed at glacial calving fronts and lognormal size-frequency distributions observed globally within open waters that remains unexplained. Here we use passive seismic monitoring to examine mechanisms of iceberg disintegration as a function of drift. Our results indicate that the shift in the size-frequency distribution of iceberg sizes observed is a product of fracture-driven iceberg disintegration and dimensional reductions through melting. We suggest that changes in the characteristic size-frequency scaling of icebergs can be explained by the emergence of a dominant set of driving processes of iceberg degradation towards the open ocean. Consequently, the size-frequency distribution required to model iceberg distributions accurately must vary according to distance from the calving front.
- ItemEvidence of probable paleotsunami deposits on Kho Khao Island, Phang Nga Province, Thailand(Springer, 2012) Yawsangratt, Supawit; Szczuciński, Witold; Chaimanee, Niran; Chatprasert, Sirapapa; Majewski, Wojciech; Lorenc, StanisławThe 2004 tsunami deposits and probable paleotsunami deposits were studied at the southern Kho Khao Island, on Andaman Sea coast of Thailand. The 2004 tsunami laid down about 8cm of fining upward medium sand and locally about 40cm of massive coarse sand with common mud clasts. The sediments were characterized by the presence of marine foraminiferal assemblage; however, already after 5years many of carbonate foraminiferal tests were partly or completely dissolved. The probable paleotsunami deposits form layer about 1m thick. It consists of massive very coarse sand with common big shells and mud clasts. Its composition suggests a marine origin and the presence of mud clasts, and similarity to the 2004 tsunami deposits suggests that the layer was left by paleotsunami, which took place probably during the late Holocene, even though two shells within the layer gave 14C ages of 40,000years or more.
- ItemFires, vegetation, and human - The history of critical transitions during the last 1000 years in Northeastern Mongolia(2022-09) Słowiński, Michał; Obremska, Milena; Avirmed, Dashtseren; Woszczyk, Michał; Adiya, Saruulzaya; Łuców, Dominika; Mroczkowska, Agnieszka; Hałaś, Agnieszka; Szczuciński, Witold; Kruk, Andrzej; Lamentowicz, Mariusz; Stańczak, Joanna; Rudaya, NataliaFires are natural phenomena that impact human behaviors, vegetation, and landscape functions. However, the long-term history of fire, especially in the permafrost marginal zone of Central Asia (Mongolia), is poorly understood. This paper presents the results of radiocarbon and short-lived radionuclides (210Pb and 137Cs) dating, pollen, geochemical, charcoal, and statistical analyses (Kohonen's artificial neural network) of sediment core obtained from Northern Mongolia (the Khentii Mountains region). Therefore, we present the first high-resolution fire history from Northern Mongolia covering the last 1000 years, based on a multiproxy analysis of peat archive data. The results revealed that most of the fires in the region were likely initiated by natural factors, which were probably related to heatwaves causing prolonged droughts. We have demonstrated the link between enhanced fires and “dzud”, a local climatic phenomenon. The number of livestock, which has been increasing for several decades, and the observed climatic changes are superimposed to cause “dzud”, a deadly combination of droughts and snowy winter, which affects fire intensity. We observed that the study area has a sensitive ecosystem that reacts quickly to climate change. In terms of changes in the vegetation, the reconstruction reflected climate variations during the last millennium, the degradation of permafrost and occurrence of fires. However, more sites with good chronologies are needed to thoroughly understand the spatial relationships between changing climate, permafrost degradation, and vegetation change, which ultimately affect the nomadic societies in the region of Central and Northern Mongolia.
- ItemFossil organic carbon utilization in marine Arctic fjord sediments by subsurface micro-organisms(2023-07) Ruben, Manuel; Hefter, Jens; Schubotz, Florence; Geibert, Walter; Butzin, Martin; Gentz, Torben; Grotheer, Hendrik; Forwick, Matthias; Szczuciński, Witold; Mollenhauer, GesineRock-derived or petrogenic organic carbon has traditionally been regarded as being non-bioavailable and bypassing the active carbon cycle when eroded. However, it has become apparent that this organic carbon might not be so inert, especially in fjord systems where petrogenic organic carbon influxes can be high, making its degradation another potential source of greenhouse gas emissions. The extent to which subsurface micro-organisms use this organic carbon is not well constrained, despite its potential impacts on global carbon cycling. Here, we performed compound-specific radiocarbon analyses on intact polar lipid–fatty acids of live micro-organisms from marine sediments in Hornsund Fjord, Svalbard. By this means, we estimate that local bacterial communities utilize between 5 ± 2% and 55 ± 6% (average of 25 ± 16%) of petrogenic organic carbon for their biosynthesis, providing evidence for the important role of petrogenic organic carbon as a substrate after sediment redeposition. We hypothesize that the lack of sufficient recently synthesized organic carbon from primary production forces micro-organisms into utilization of petrogenic organic carbon as an alternative energy source. The input of petrogenic organic carbon to marine sediments and subsequent utilization by subsurface micro-organisms represents a natural source of fossil greenhouse gas emissions over geological timescales.
- ItemIce tectonics and bedrock relief control on glacial sedimentation – an example from Hansbreen, Spitsbergen(Pracownia Sztuk Plastycznych Sp. z o.o., 2000) Rachleiwcz, Grzegorz; Szczuciński, WitoldHansbreen, a tidewater glacier in southern Spitsbergen, was investigated to reveal the relationship between its tectonic and mode of deposition. In the land terminating zone the bedrock threshold plays major role in sedimentation by creating compression conditions. It causes the most of sediment to be released supraglacially, and redeposited in form of debris flows. The upward debris transport is done mostly by folding deformation of basal ice layer with a minor participation of thrusts. In observed outcrops no subglacial deformed layer of till was found. The debris occurrence was associated only with the debris-rich basal ice layer. However on the foreland exists subglacial till, partly formed in flutings, also with micromorphological evidence of deformations. Various bedrock morphology is supposed to differentiate basal conditions. The flat, but undulated, regelation favouring conditions, leads to the debris-rich basal ice layer formation, however inclined but non undulated relief prefers deformed subglacial sediments development. No structural or sedimentological evidence of surge events were found in the tributary glaciers (Fuglebreen, Tuvbreen), hence this phenomenon is thought to be limited to the main ice stream.
- ItemLate Holocene Sedimentation and Environmental Change Record in Billefjorden, Svalbard(2004) Szczuciński, Witold; Lorenc, StanisławThe Late Holocene sedimentation in Billefjorden (Svalbard) was studied through investigations of modern sedimentation conditions and their effects recorded in sediments. Sedimentation in the fjord is dominated by settling from surface turbid water plumes originating from rivers and subglacial outflows of tidewater glacier. Sedimentation is confined to the summer season (July - August) and is largely influenced by flocculation. It results in high particulate matter fluxes (up to 100 g m-2 day-1), poorly sorted sediments, and trapping of most of the sediments in the proximal few hundred meters (in case of rivers ending on tidal flats – flocculation occurs on tidal flat) to a couple of km in the case of tidewater glacier (flocculation happens after reaching the fjord waters). In the fall season, sedimentation rates are much smaller – mainly due to a smaller sediment supply but also in the effect of a largely diminished flocculation process. The latter one was found to be controlled primarily by the mixing of fresh and saline waters (so by freshwater inflow) and not by SPM concentrations. Sediment accumulation rates decrease exponentially from the source with more than 4 cm per year in the proximal settings to about 0.1 cm y-1 in the central basin. Sedimentation from icebergs has at least one order of magnitude lower rates. Fjord bottom sediments are mostly muds with bimodal grain size distribution (due to at least two sedimentation processes: suspension settling and iceberg rafting). Differences in their chemical (major, trace elements, and REE) mineralogical and coarse grain fraction composition are small but distinct. The deposits can be divided into regions supplied by local sources (e.g. Adolfbukta, Petuniabukta, Mimerbukta, central basin, entrance sill), supporting the conclusion of sediment trapping in proximal settings. The influence of rafted sediments is visible – especially in central basin sediments because the bulk of them is supplied from catchments of different geology. In the studied cores, early diagenesis is exemplified by compaction, small sediment mixing (through bioturbation and physical processes), and chemical processes associated with the redox zone. The most spectacular one is shown by the dissolution of benthic agglutinated foraminifera cement and their sharp decline in the upper few cm of sediment cores. A study of the multiproxy signal revealed several changes associated with environmental as well as anthropogenic changes. The most striking are changes in sediment accumulation rates in the fjord central basin. In the period 1300 AD to about 1895 (maximum extent of LIA glaciers), the rates were at least one order of magnitude lower than after LIA. The latter is also the highest in the whole Holocene period. Smaller fluctuations were also associated with tidewater proximal cores where they decrease with increasing distance from the sediment source (glacier retreat). An unusual situation was observed in the core located in the vicinity of Pyramiden (coal mine and settlement active between 1945 and 1998) where in the 50s sediment accumulation rates were elevated possibly in association with earthworks in the settlement and in the mining area. The sediment chemical composition also changed through time – the most distinct change happened around the 1950s, when in the central basin cores increased the relative ratio between carbonate-related elements (local catchments) and silica and aluminosilicate-related elements (partly controlled by input from icebergs). It well correlates with tidewater glacier retreat into the shallower water area and consequently decreasing iceberg production. One of the most striking changes in the sediments associated with anthropogenic activity is significantly elevated coal sand and dust content in the sediments, which concentrations well correlates with the intensity of coal mining in the Pyramiden. In light of projected future climatic changes in this part of the Arctic, the main changes are expected in sediment budget. With increasing freshwater (due to increasing precipitation and ablation) and consequently in sediment delivery, the average sediment accumulation rate will increase. However, it will be even more concentrated in proximal settings (prolonged and intensified conditions for the flocculation process). The input of deposition from icebergs will be likely smaller since the only tidewater glacier is retreating into a more and more shallow setting. Parts of the thesis were published as: Szczuciński, W., Zajączkowski, M., 2012 – Factors controlling downward fluxes of particulate matter in glacier-contact and non-glacier contact settings in a subpolar fjord (Billefjorden, Svalbard). Sediments, Morphology and Sedimentary Processes on Continental Shelves: Advances in technologies, research and applications (Special Publication 44 of the IAS), Li M., Sherwood C., Hill P. (eds). Wiley-Blackwell Publishing, 369-386. (https://onlinelibrary.wiley.com/doi/10.1002/9781118311172.ch18) Szczuciński, W., Zajączkowski, M., Scholten, J., 2009 – Sediment accumulation rates in subpolar fjords – impact of post-Little Ice Age glaciers retreat, Billefjorden, Svalbard. Estuarine, Coastal and Shelf Science 85(3): 345-356. (https://www.sciencedirect.com/science/article/abs/pii/S0272771409004193)
- ItemLate Holocene Vistula River floods recorded in grain size distributions and diatom assemblages of marine sediments of the Gulf of Gdańsk (Baltic Sea)(Elsevier, 2023-05-01) Szcześniak, Marta; Kokociński, Mikołaj; Jagodziński, Robert; Pleskot, Krzysztof; Zajączkowski, Marek; Szczuciński, WitoldDuring the large flood of the Vistula River in 2010, the riverine brackish water surface plume extended up to 70 km into the Gulf of Gdańsk (Baltic Sea), leaving a thin layer of medium-grained sand deposits. It inspired a search for palaeoflood records in marine sediments. Thus, we aimed to identify the most useful flood indicators and apply them to reveal palaeoflood records in sediment cores from the Gulf of Gdańsk. The study is based on analyses of surface samples, collected during and one year after the 2010 flood, and two long sediment cores, which were subjected to high-resolution grain size, diatom, and geochemical analyses, while chronology was based on the combined AMS 14C, 210Pb and 137Cs dating. It was found that, in a water depth of less than 30 m, modern large flood deposits were not preserved after a year. Sediment cores retrieved from greater water depths (over 60 m) were composed of sandy mud, and most of the 1 cm thick sediment samples were characterized by unimodal grain size distribution. However, some of the samples were bimodal, with the additional mode in fine-grained fractions, which is interpreted to be the result of direct deposition from riverine flood surface water plume. The diatom assemblages revealed a moderate downcore variability, except for the intervals characterized by bimodal grain size distributions. They contained elevated amounts of benthic oligohalobous (freshwater) and decreased euhalobous and mesohalobous taxa, supporting the likely interpretation of these layers as deposited during river flood events. During the last c. 4 ka, a dozen major flood events were identified. However, their application to flood climate reconstruction is challenging because of relatively frequent and partly unknown changes in major river mouth positions in the past. We suggest that thin deposits of major floods left on the seafloor and subjected to further mixing maybe still recognized using a combination of high-resolution grain size distribution and diatom analyses supplemented by a good understanding of the depositional system history.
- ItemLate Weichselian and Holocene palaeoceanography of Storfjordrenna, southern Svalbard(2015) Łącka, Magdalena; Zajączkowski, Marek; Forwick, Matthias; Szczuciński, WitoldMultiproxy analyses (including benthic and planktonic foraminifera, δ18O and δ13C records, grain-size distribution, ice-rafted debris, XRF geochemistry and magnetic susceptibility) were performed on a 14C-dated marine sediment core from Storfjordrenna, located off of southern Svalbard. The sediments in the core cover the termination of Bølling–Allerød, the Younger Dryas and the Holocene and reflect general changes in the oceanography/climate of the European Arctic after the last glaciation. Grounded ice of the last Svalbard–Barents Sea Ice Sheet retreated from the coring site ca. 13 950 cal yr BP. During the transition from the subglacial to glaciomarine setting, Arctic Waters dominated the hydrography in Storfjordrenna. However, the waters were not uniformly cold and experienced several warmer spells. A progressive warming and marked change in the nature of the hydrology occurred during the early Holocene. Relatively warm and saline Atlantic Water began to dominate the hydrography starting from approximately 9600 cal yr BP. Although the climate in eastern Svalbard was milder at that time than at present (smaller glaciers), two periods of slight cooling were observed in 9000–8000 and 6000–5500 cal yr BP. A change in the Storfjordrenna oceanography occurred at the beginning of the late Holocene (i.e. 3600 cal yr BP) synchronously with glacier growth on land and enhanced bottom current velocities. Although cooling was observed in the Surface Water, Atlantic Water remained present in the deeper portion of the water column of Storfjordrenna.
- ItemMultiproxy paleoceanographic study from the western Barents Sea reveals dramatic Younger Dryas onset followed by oscillatory warming trend(Springer Nature, 2020-09) Łącka, Magdalena; Michalska, Danuta; Pawłowska, Joanna; Szymańska, Natalia; Szczuciński, Witold; Forwick, Matthias; Zajączkowski, MarekThe Younger Dryas (YD) is recognized as a cool period that began and ended abruptly during a time of general warming at the end of the last glacial. New multi-proxy data from a sediment gravity core from Storfjordrenna (western Barents Sea, 253 m water depth) reveals that the onset of the YD occurred as a single short-lived dramatic environment deterioration, whereas the subsequent warming was oscillatory. The water masses in the western Barents Sea were likely strongly stratified at the onset of the YD, possibly due to runoff of meltwater combined with perennial sea-ice cover, the latter may last up to several decades without any brake-up. Consequently, anoxic conditions prevailed at the bottom of Storfjordrenna, leading to a sharp reduction of benthic biota and the appearance of vivianite microconcretions which formation is favoured by reducing conditions. While the anoxic conditions in Storfjordrenna were transient, the unfavorable conditions for benthic foraminifera lasted for c. 1300 years. We suggest that the Pre-Boreal Oscillation, just after the onset of the Holocene, may have been a continuation of the oscillatory warming trend during the YD.
- ItemPreliminary evidence of an endangered species benefiting from moderate climate warming: A palaeolimnological study of the charophyte Lychnothamnus barbatus(John Wiley & Sons Ltd., 2021) Brzozowski, Michał; Kowalewski, Grzegorz; Szczuciński, Witold; Kaczmarek, Lech; Pełechaty, Mariusz1. In a time of rapid environmental changes, identification of the effects of climate warming on charophytes (Characeae, Charophyta) will enable the optimization of conservation measures, especially for extremely rare species. Lychnothamnus barbatus is one of the rarest charophytes worldwide, which has decreased in the number of occupied sites over the last century. However, the recolonization of former sites has been observed in recent years (e.g. Lake Ku znickie, Poland). The study aimed to analyse the effects of climatic changes and human pressure on the L. barbatus population. 2. Three 30 cm sediment cores were collected from minimum, average, and maximum depths of L. barbatus occurrence to determine the past vegetation composition. Sediment cores were dated using the radioisotopes lead-210, caesium-137, and carbon-14. A spatial analysis of the lake catchment changes during the last 120 years was also conducted. 3. The study demonstrated L. barbatus presence in Lake Kuźnickie at the beginning of the 16th century. However, a sharp increase in the proportion of this species in the vegetation community occurred in the 19th century and during climate warming at the end of the Little Ice Age. Factors that significantly influenced the present occurrence of the L. barbatus population included improvement in water quality and the oospore bank deposited in the bottom sediments. 4. This study is the first palaeoreconstruction in a modern lake dominated by L. barbatus. Based on the history of L. barbatus in Lake Kuźnickie after the end of the Little Ice Age, the positive effect of climate warming on the contemporary recovery of this charophyte is postulated. 5. The reaction of L. barbatus to climate warming appears to differ from commonly accepted scenarios for aquatic macrophytes because its recovery in the past and at present coincided with increases in air temperature. This research indicated the appropriate management and conservation practices for lakes with L. barbatus populations.
- ItemSedimentary evidence for a mid-Holocene iceberg-generated tsunami in a coastal lake, west Greenland(2015-12) Long, Antony J.; Szczuciński, Witold; Lawrence, ThomasWe report sedimentological evidence for a tsunami from a coastal lake at Innaarsuit, Disko Bugt (west Greenland), which was most likely generated by a rolling iceberg. The tsunami invaded the lake c. 6000 years ago, during a period of time when relative sea level (RSL) was falling quickly because of isostatic rebound. We use the background rate of RSL fall, together with an age model for the sediment sequence, to infer a minimum wave run-up during the event of c. 3.3 m. The stratigraphic signature of the event bears similarities to that described from studies of the early-Holocene Storegga slide tsunami in Norwegian coastal basins. Conditions conducive to iceberg tsunami include a supply of icebergs, deep water close to the shore, a depositional setting protected from storms or landslide tsunami, and a coastal configuration that has the potential to amplify the height of tsunami waves as water depths shallow and the waves approach and impact the coast. Future warming of polar regions will lead to increased calving and iceberg production, at a time when human use of polar coasts will also grow. We predict, therefore, that iceberg-generated tsunami will become a growing hazard in polar coastal waters, especially in areas adjacent to large, fast-flowing, marine-terminating ice streams that are close to human populations or infrastructure.
- ItemSmall impact cratering processes produce distinctive charcoal assemblages(2022-11) Losiak, Anna; Belcher, C. M.; Plado, J.; Jõeleht, A.; Herd, C. D. K.; Kofman, R. S.; Szokaluk, Monika; Szczuciński, Witold; Muszyński, Andrzej; Wild, E. M.; Baker, S. J.The frequency of crater-producing asteroid impacts on Earth is not known. Of the predicted Holocene asteroid impact craters of <200 m diameter, only ~30% have been located. Until now there has been no way to distinguish them from “normal” terrestrial structures unless pieces of iron meteorites were found nearby. We show that the reflective properties of charcoal found in the proximal ejecta of small impact craters are distinct from those produced by wildfires. Impact-produced charcoals and wildfire charcoals must derive from different heating regimes. We suggest that charcoal with specific reflective properties may help to recognize the meteoritic origin of small craters.
- ItemSubmarine geomorphology at the front of the retreating Hansbreen tidewater glacier, Hornsund fjord, southwest Spitsbergen(Taylor & Francis Online, 2018-03-01) Ćwiąkała, Joanna; Moskalik, Mateusz; Forwick, Matthias; Wojtysiak, Kacper; Giżejewski, Jerzy; Szczuciński, WitoldA 1:10,000 scale bathymetric map as well as 1:20,000 scale backscattering and geomorphological maps of two bays Isbjørnhamna and Hansbukta in the Hornsund fjord (Spitsbergen) present the submarine relief that was primarily formed during and after the retreat of the Hansbreen tidewater glacier. Geomorphological mapping was performed using multibeam bathymetric data and seismoacoustic profiling. The identified landforms include two types of transverse ridges interpreted as terminal and annual moraines, flat areas that are depressions filled with glaciomarine sediments, iceberg-generated pits and ploughmarks, pockmarks and fields of megaripples. Most of the identified landforms are genetically related to the retreat of Hansbreen since the termination of the Little Ice Age at the beginning of the twentieth century. Although Hansbreen has been speculated to be a surge-type glacier, no evidence of surging was identified in the submarine landform assemblage, which is in accordance with the absence of historically documented surges for that period.
- ItemSubmarine landform assemblages and sedimentary processes related to glacier surging in Kongsfjorden, Svalbard(2015-12) Streuff, Katharina; Forwick, Matthias; Szczuciński, Witold; Andreassen, Karin; Ó Cofaigh, ColmHigh-resolution swath-bathymetry data from inner Kongsfjorden, Svalbard, reveal characteristic landform assemblages formed during and after surges of tidewater glaciers, and provide new insights into the dynamics of surging glaciers. Glacier front oscillations and overriding related to surge activity lead to the formation of overridden moraines, glacial lineations of two types, terminal moraines, associated debris lobes and De Geer moraines. In contrast to submarine landform assemblages from other Svalbard fjords, the occurrence of two kinds of glacial lineations and the presence of De Geer moraines suggest variability in the landforms produced by surge-type tidewater glaciers. All the landforms in inner Kongsfjorden were deposited during the last c. 150 years. Lithological and acoustic data from the innermost fjord reveal that suspension settling from meltwater plumes as well as ice rafting are dominant sedimentary processes in the fjord, leading to the deposition of stratified glacimarine muds with variable numbers of clasts. Reworking of sediments by glacier surging results in the deposition of sediment lobes containing massive glacimarine muds. Two sediment cores reveal minimum sediment accumulation rates related to the Kongsvegen surge from 1948; these were 30 cm a-1 approximately 2.5 km beyond the glacier front shortly after surge termination, and rapidly dropped to an average rate of 1.8 cm a-1 in ∼1950, during glacier retreat.
- ItemTemperature increase altered Daphnia community structure in artificially heated lakes: a potential scenario for a warmer future(Springer Nature, 2020-08) Dziuba, Marcin; Herdegen‑Radwan, Magdalena; Pluta, Estera; Wejnerowski, Łukasz; Szczuciński, Witold; Cerbin, SławekUnder conditions of global warming, organisms are expected to track their thermal preferences, invading new habitats at higher latitudes and altitudes and altering the structure of local communities. To fend off potential invaders, indigenous communities/populations will have to rapidly adapt to the increase in temperature. In this study, we tested if decades of artificial water heating changed the structure of communities and populations of the Daphnia longispina species complex. We compared the species composition of contemporary Daphnia communities inhabiting five lakes heated by power plants and four non-heated control lakes. The heated lakes are ca. 3–4 °C warmer, as all lakes are expected to be by 2100 according to climate change forecasts. We also genotyped subfossil resting eggs to describe past shifts in Daphnia community structure that were induced by lake heating. Both approaches revealed a rapid replacement of indigenous D. longispina and D. cucullata by invader D. galeata immediately after the onset of heating, followed by a gradual recovery of the D. cucullata population. Our findings clearly indicate that, in response to global warming, community restructuring may occur faster than evolutionary adaptation. The eventual recolonisation by D. cucullata indicates that adaptation to novel conditions can be time-lagged, and suggests that the long-term consequences of ecosystem disturbance may differ from short-term observations.
- ItemThe First International Conference on ‘Processes and Palaeo-Environmental Changes in the Arctic: From Past to Present’ (PalaeoArc)(Instytut Geologii UAM, 2019-08) Lyså, Astrid; Benediktsson, ĺvar Örn; Emery, Andy; Gregoire, Lauren; Jennings, Anne; Morigi, Caterina; Müller, Juliane; O´Regan, Matt; Sarala, Pertti; Stokes, Chris; Szczuciński, Witold; Winsborrow, Monica