Field of Study – Geology (N 005)

Peatlands are among the most important terrestrial ecosystems, playing a crucial role in carbon sequestration, water quality regulation, and biodiversity conservation. In Lithuania and across the Baltic region, increasing efforts are being made to restore degraded peatlands in order to reduce greenhouse gas emissions and improve ecosystem health. However, due to their high organic matter content and large surface area, peat soils are also effective at accumulating hydrophobic organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) and pesticides. These pollutants originate from atmospheric deposition, agricultural runoff, urban sources, and combustion processes, with peatland fires acting as an additional major source of PAHs.

Changes in peatland hydrology—both drainage and restoration—can mobilize contaminants that have accumulated over long periods, potentially turning peatlands into secondary sources of pollution for surface and groundwater. Despite this risk, the processes governing the accumulation, origin, and transport of organic pollutants in Lithuanian peatlands remain poorly understood.

The aim of this dissertation is to comprehensively investigate the history of organic contaminant accumulation, their sources, and transport mechanisms in different types of peatlands across Lithuania. The study will focus on representative sites, including bogs and fens, as well as areas subject to varying degrees of anthropogenic impact (e.g., near agricultural land, urban areas, roads, exploited and relatively undisturbed sites), in order to assess the influence of hydrological changes and land use.

An integrated methodological approach will be applied, combining vertical peat core analysis to reconstruct long-term contamination history, hydrological monitoring of pore water, surface water, and groundwater, and chemical fingerprinting techniques (e.g., diagnostic PAH ratios) to identify pollution sources. Laboratory analyses will include extraction, chromatographic cleanup, and gas chromatography–mass spectrometry (GC–MS) for quantifying PAHs and selected pesticides. Hydrological and chemical data will be used to evaluate both vertical and horizontal contaminant fluxes.

Expected outcomes include the development of a regional database of organic pollutant concentrations in Lithuanian peatlands, identification of key migration pathways and seasonal mobilization patterns, and quantitative estimates of pollutant retention and export under different hydrological conditions. Additionally, predictive models will be developed to assess the impact of peatland drainage and restoration on contaminant mobility. The results will help determine whether peatlands function primarily as long-term pollutant sinks or as potential secondary pollution sources, and will provide science-based recommendations for wetland restoration and water quality management in Lithuania and the broader Baltic region.

Managing nature during times of rapid environmental dynamics as well as modelling of the future changes, knowledge of ecosystem response to climatic fluctuations throughout the geological past analysed on diachronic (time) and geographic (space) perspective is required. The Quaternary, geological period with typical dynamics of cold and warm climatic intervals, was characterized by significant fluctuations in the palaeoecosystem regime, therefore this geological period is exceptionally important in assessing long-term trends in similar changes. All together that provide more comprehensive insights into the environmental behaviour and is especially important analysing situation in the transitional environmental (glaciated-subglacial), climatic (oceanic-continental) and floristic (boreo-nemoral) zones, where most pronounced fluctuations might have occurred. Insights into the pattern of these changes are crucial to predicting future environmental and climatic regimes. Furthermore, this is very important in modelling the dynamics of future ecosystems or their individual components and in developing tools and methods to prevent undesirable aspects of change.

In the major part of the European territory formation of the modern ecosystems started after the Pleniweichselian Maximum, at about 20 thousand years ago, with the beginning of the degradation of the youngest, Scandinavian, glacier. At that time, the periglacial zone, i.e. territory situated outside the maximum extent of the Scandinavian Ice sheet, are of crucial importance, as numerous processes, including soil formation, forestation and etc., started from these zones to the newly deglaciated areas. Significant number of plants and animals survived cold interval (glaciation) next to the ice sheet establishing to the newly deglaciated areas after the ice retreat of northern and northeaster Europe.

Studies of varying scope, detail and complexity, conducted over many years in the northern, central and western parts of the continent, have made it possible to characterize in quite detail the history of the development of palaeoecosystems after the onset of global warming, including assessing the role of periglacial areas in the formation of ecosystems in glaciated regions (Birks and Birks, 2004; Willis and van Andel, 2004; Giesecke, 2005a,b; Latałowa and van der Knaap, 2006; Margielewski, 2006; Birks and Willis, 2008; Binney et al., 2009). In addition, the main features of the vegetation history, glacier dynamics, soil erosion, etc. in the aforementioned parts of the continent have been described within high chronological reliability (Lowe et al., 2008; Rasmussen et al., 2007; Walker et al., 1999, 2012; Syrykh et al., 2021; Pł´ociennik et al., 2022; Andreev et al., 2021; Salonen et al., 2024). Meanwhile, the eastern part of the European continent is significantly less studied in terms of paleoecosystem knowledge. Moreover, paleoenvironmental dynamics data from regions spanning the eastern part of the continent have highlighted notable discrepancies in the nature, scale, and even chronological allocations of recorded paleoecosystem fluctuations (Wohlfarth et al., 1999, 2002, 2004, 2006, 2007; Subetto et al., 2002; Stančikaitė et al., 2008, 2009; Zernitskaya et al., 2015; Herzschuh et al., 2023; Renssen and Isarin, 2001; Herzschuh et al., 2023). It is obvious that scientific discussions analyzing the history of paleoecosystems across Europe after the Pleniweichselian Maximum require additional detailed, comprehensive studies along the eastern gradient. Alongside with this, knowledge of the interaction of ecosystem components on the various time scales is of vital importance, as these are unlikely to be linear.

Due to the geographical situation of the Ukrainian territory, a major part of the country is attributed to the periglacial zone of the Late Weichselian Glaciation, i.e. was free of ice during the Pleniweichselian maximum, this region provides exceptional opportunities for multi-proxy palaeoenvironmental and palaeoclimatic reconstructions. Meantime region host various types of paleo-records, i.e. lake sediments, peat deposits, marine, delta and fluvial deposits, speleothemes, loess deposits, tree ring, archaeological data and etc. Beside that country is located at the conjunction of Atlantic, Mediterranean and Siberian air masses that determined strong climatic regimes during the various intervals of the geological past. At the same time, the region was characterized by significant biodiversity, which was very important for the survival of both plants and animals or insects in the territory (refugee area) during maximum glaciation and for their subsequent spread into the deglaciated areas. It is obvious that in order to study the history of ecosystem development in the deglaciated areas, it is necessary to understand the “prehistory” of these transformations, i.e. to study the processes and transformations and the causes that determined them in periglacial zones, linking the information obtained with the ecosystem formation processes that took place further north. Obviously, territory of Ukraine might be indicated as a key region constructing central-northeastern-northern European gradient with the further integration of existing databases.

Identification of the palaeoecosystem dynamics applying multidisciplinary (geological, geomorphological, lithological, paleobotanical, isotopic and etc.) approach, alongside the gradient following from the periglacial zone in Ukraine to the eastern Baltic region after the Pleniweichselian maximum (over the past 18-20 thousand years) directly influenced by the glacier, is the main aim of the planned research.

Achieving the main aim of the doctoral studies, it is planned to carry out detailed lithological (LOI, grain-size and MSus), paleobotanical (palynological and plant macroremains) and isotopic (14C) studies in western Ukraine. Based on the information obtained, assessing the vegetation composition, regime of the sedimentological basin and climatic changes in the territory after the Pleniweichselian maximum will be analysed. Availability of the data characterizing the history of palaeoecosystem development in the Ukraine is quite poor i.e. of low stratigraphic resolution, lacking independent chronological information and regional data correlation or interpretation (Kremenetski, 1995; Huhmann et al., 2004; Kalinovych, 2004, 2013; Stachowicz-Rybkaet al., 2009; Kołaczek et al., 2016; Kalinovych, 2004, 2013; Stachowicz-Rybka et al., 2009). The latter fact is particularly important incorporating a new data into European data sets, therefore, the research will emphasize the interpretation of the information obtained in the local and regional context. Also, based on the identified (a)biotic markers we are going to characterize the sedimentary response of lacustrine systems during the periods of climatic shifts of different magnitude. Alongside with this exploration of the vegetation history and sedimentary dynamics will be discussed emphasising pattern of local and regional changes. Summarizing the original research data obtained, the correlation of the obtained data along the NE-W European gradient will be performed, emphasizing the relationship of the identified changes with the fluctuations recorded in the Northern Hemisphere and globally. The application of new available data analysis methods, including statistical information evaluation, correlation and interpretation tools, can significantly contribute to the formation of a modern model of the development of palaeoecosystems based on the assessment of their dynamics.

 Vegetation is a key reservoir of biological diversity on our planet; one of its major ecological, social and economic services. Unfortunately, in the context of the current global crisis it is suffering from both climatic factors and anthropogenic pressure. Anticipating and modelling vegetation response to future challenges needs information on past reactions to similar forcing. Reliable reconstructions of the postglacial vegetation dynamics are crucial improving our understanding of the past ecosystem dynamics giving an opportunity for future scenarios testing.

This project aims to achieve new understanding of the spatiotemporal dynamics of the tree species in the south-eastern margin of the Scandinavian Glaciation throughout the Lateglacial and Holocene combining palaeoecological and genetic approach. To address described challenge, we suggest the high-resolution multi-proxy palaeoecological and palaeo-genomics (molecular) investigations of plant macro remains, including identification of genetic lineages, of the common tree taxa (Pinus, Picea, Betula and etc.). With these data we will assess new information concerning, refugial areas and respective migration routes of the particular taxa, re-colonisation pattern of the deglaciated territories and subsequent formation of the vegetation cover, including identification of the genetic lineages, in the transitional palaeoenvironmental (glacial-subglacial), climatic (oceanic-continental) and floristic (boreo-nemoral) zone, close to the limits of the species natural distribution range. Although numerous plant species have been investigated with regard to their postglacial history incorporation of palaeoecological data and that describing the genetic variations of the particular taxa in the geological past is limited in the Eastern Baltic so far.

Analysis of the obtained data, including the application of the statistical approach, will provide more comprehensive insights into the palaeovegetation behaviour and that is especially important analysing situation in context of both internal and external drivers as well as making future forecast.

The Zhytomyr region of Ukraine has been severely affected by the military conflict. In order to overcome its consequences and ensure sustainable development in line with environmental standards, it is necessary to accurately record, study and assess the extent of the ecological catastrophe, and to develop a system of indicators describing these phenomena. Explosions, fires and accidents of various magnitudes, including incidents at oil storage facilities, have occurred in the study area. The damage caused leads to risks such as erosion, soil contamination, and disruption of geo- and bio-ecosystems.

Contaminants accumulate in the soil and are subsequently released into other environments. The mobility of pollutants in the environment depends on the physicochemical properties of the soil, including its granulometric and mineralogical composition, humus content, cation exchange capacity, pH level, etc. The prediction of contaminant migration can be facilitated by the identification of landscape and geochemical barriers. Planning for the restoration of the geo-environment should take into account the level of pollution, the extent of damage, and the landscape and geochemical conditions that influence the transport of pollutants.

The study will analyse satellite imagery to identify war-damaged areas and assess the extent of damage. Soil samples will be taken in the affected areas to determine concentrations of heavy metals such as mercury, lead, iron, zinc, cadmium, aluminium and copper. These metals are the most frequent sources of contamination to soil from explosive devices. In addition, the presence of sulphur and nitrogen compounds from petroleum products will be assessed. The adsorptive, structural and textural properties of soils and their role in contaminant transport will be investigated, as well as the influence of geochemical barriers on contaminant retention.

The results will be used to develop recommendations to address soil contamination and erosion, as well as to propose monitoring protocols and strategies for the protection of damaged areas.