Northeastern Estonia Research Articles

Deformation structures as key hints for interpretation of ice sheet dynamics - A case study from northeastern Estonia

Late Pleistocene glaciolacustrine sediments in the northern part of Estonia show a wide spectrum of ductile and brittle deformation structures like: (1) injection structures, dish structures, load casts, pseudonodules, ball-and-pillow structures, flame structures and fragments of broken-up sandy laminae all occurring in three internally deformed layers separated by undeformed layers, (2) large-scale upright gentle folds of outcrop size, (3) faults and fractures, and (4) water-escape structures (hydrofractures). We investigate the potential trigger mechanisms for the development of these deformation structures, their relationship in space and time as well as the lithological and geometrical features of soft-sediment deformation structures necessary to recognise deformation mechanisms. Based on comprehensive geological and numerical investigations, we link their origin to two major processes: (1) glacial rebound of Earth's crust causing earthquakes and (2) proglacial and submarginal glaciotectonic processes related to local oscillation of the ice-sheet front. We suggest criteria which allow us to recognise these two trigger mechanisms and propose a new proxy for reconstructing glacigenic processes and environments based on recognised soft-sediment deformation structures and their interrelationships. Our findings also highlight the significance of water saturation levels in glacigenic sediments and their impact on deformation processes. Furthermore, we introduce new types of water-escape structures that develop in proglacial marginal and/or submarginal settings. Our results contribute to a more nuanced interpretation of glacial activity and environmental conditions during the Late Pleistocene period in the study area.

The number of Estonian black fungus gnats (Diptera, Sciaridae) doubled: the first records of 64 species.

Adult sciarid flies are small to medium-sized, delicate insects, typically black in colour and belonging to the superfamily Sciaroidea within the order Diptera. They exhibit a uniform appearance. Distinguishing them from other families of Sciaroidea is primarily achieved through their typical wing venation. Sciaridae are common in both natural and semi-natural ecosystems, where they play a significant role in decomposition during their larval stage. Prior to the current study, only one specific research project had been conducted on Sciaridae in Estonia. The number of sciarid species identified in Estonia was set at 67. This research, conducted in north-eastern Estonia during 2015 and 2016, presents a comprehensive overview of Sciaridae diversity, shedding light on previously understudied aspects of Estonia's biodiversity. A total of 1038 specimens were identified, representing 91 species, amongst which 64 were previously unknown to Estonia. Notably, Corynopterawinnertzi (Mohrig, 1993) emerged as the most abundant species, followed by Corynopterairmgardis (Lengersdorf, 1930), Corynopteracrassistylata (Frey, 1948) and Bradysiatrivittata (Staeger, 1840). The genus Corynoptera Winnertz, 1867 exhibited the highest diversity, consistent with findings from broader European studies. This study underscores the importance of ongoing surveys for better understanding the distribution and composition of Sciaridae species in Estonia, emphasising the need for further research to delve into the intricate ecology and biology of these insects.

Underground mining magnifies drought impacts in an adjacent protected raised bog

AbstractStable and high water levels are crucial for wetland ecosystems, impacting their state, vegetation and conservation. To make informed conservation decisions, it is essential to consider the full range of ecosystem‐level threats associated with artificially lowered water levels. This becomes particularly challenging when dealing with diffuse and indirect impacts, such as ombrotrophic bogs near underground mining activities that extract groundwater. In this study, we monitored water tables using automatic pressure loggers over an 11‐year period in a protected hemiboreal bog and in drained peatland surrounding it in northeastern Estonia. The bog is located within the groundwater cone of depression caused by an adjacent oil‐shale mine, approximately 60–70 m deep. By comparing monitoring points along the bog‐drained forest gradient and analysing time series data, we were able to distinguish the influences of climate and mining activities on water levels in the bog. Our findings indicate that mining activities have clear effects on deeper bedrock aquifers and the bog itself, exacerbating the impacts of recent drought events. The dynamics of the hydraulic heads at different monitoring points reveal local infiltration ‘windows’ within the bog, likely resulting from underlying fracture zones in the bedrock. Considering the escalating intensity of climate change, mires' vulnerability to these combined impacts is expected to increase. Therefore, adopting a precautionary and forward‐thinking conservation strategy is crucial when addressing ongoing or future drainage and mining activities near protected wetlands.

U–Pb geochronology of detrital zircon from the Ediacaran and Cambrian sedimentary successions of NE Estonia and Volyn region of Ukraine: Implications for the provenance and comparison with other areas within Baltica

Trends in detrital zircon age distribution patterns are used to constrain the paleotectonic and paleogeographic conditions during deposition of the late Ediacaran - Early Cambrian sedimentary successions in northwestern, western, and southwestern Baltica. Detrital zircons from three sandstone samples collected from a drill-core drilled in northeastern Estonia and four sandstone samples collected from three drill-cores located in the Volyn region of Ukraine were dated using the U-Pb LA-ICP-MS isotope technique. The resulting age patterns are compared with the published data for southwestern Ukraine and Moldova, eastern Poland, Belarus, and northwestern Russia to constrain the late Ediacaran - Early Cambrian evolution of the sedimentary basins developed on Baltica. All sedimentary basins from these areas of Baltica show a transition during that interval from a passive continental margin to collisional settings, which has been triggered by the pre-Schythides and Santacrusades orogenies along the south-southwestern and, to a lesser extent, by the Timanian Orogeny along the north-northeastern and eastern (in modern coordinates) margins of Baltica.

Coxiella burnetii Seroprevalence and Associated Risk Factors in Cattle, Sheep, and Goats in Estonia.

Q fever, a disease caused by Coxiella burnetii (CB), is an emerging zoonotic health problem. The prevalence data from potential sources are valuable for assessing the risk to human and animal health. To estimate the prevalence of CB antibodies in Estonian ruminants, pooled milk and serum samples from cattle (Bos taurus) and pooled serum samples from sheep (Ovis aries) and goats (Capra hircus) were analyzed. Additionally, bulk tank milk samples (BTM; n = 72) were analyzed for the presence of CB DNA. Questionnaires and herd-level datasets were used to identify the risk factors for exposure using binary logistic regression analysis. The prevalence of CB-positive dairy cattle herds (27.16%) was significantly higher than that in beef cattle herds (6.67%) and sheep flocks (2.35%). No CB antibodies were detected in the goat flocks. CB DNA was found in 11.36% of the BTM samples. The odds of seropositivity were higher in dairy cattle herds, with an increasing number of cattle in the herd, and with location in southwestern, northeastern and northwestern Estonia. Dairy cattle herds had higher odds of testing positive for CB in BTM if the dairy cows were kept loose and lower odds if the herd was located in northwestern Estonia.

Bedrock deformations in northeastern Estonia based on ground-penetrating radar data

Bedrock deformations in northeastern Estonia based on ground-penetrating radar data

GEOLOGY AND GEOCHEMISTRY OF A PALEOPROTEROZOIC IRON MINERALIZATION IN NORTH-EASTERN ESTONIA

The Estonian Precambrian basement is considered as a southern continuation of the Fennoscandian Shield of the East European Craton. Magnetite and sulphide mineralization is historically known in the Jõhvi structural zone, North-eastern Estonia. The mineralized beds are subvertical, with complicated internal structural outlines and a large range of rock types. The newly presented data of 1700 structural measurements and 110 geochemical samples are based on the analysis of two new inclined boreholes drilled in 2019–2020. Magnetite occurs as anhedral grains elongated along the rock fabric, as rounded inclusions in other minerals, or as tiny platelets along grain edges and along cleavage planes of amphibole and biotite. Sulphides are present as pyrite, pyrrhotite in addition to minor chalcopyrite, arsenopyrite and iron arsenide – loellingite, galena and sphalerite. Loellingite and arsenopyrite are commonly related to quartz-feldspar veining. Several samples show elevated Au content (up to 205 ppb), which is often observed in magnetite-sulphide mineralized beds, but sometimes in surrounding garnet gneisses as well. The study reveals unusually high manganese contents of 0.2–13.6 wt% in a number of mineralized samples and occasionally in the surrounding gneisses. The new drill core data support the understanding that the Jõhvi Zone is geologically similar to Bergslagen in Sweden and possibly to Orijärvi in southern Finland.

A Meta-Analytical Investigation of the Gap between Measured and Predicted Inter-Population Genetic Diversity in Species of High Conservation Concern-The Case of the Critically Endangered European Mink Mustela lutreola L., 1761.

Although properly designed sampling in population genetic studies is of key importance for planning evidence-informed conservation measures, sampling strategies are rarely discussed. This is the case for the European mink Mustela lutreola, a critically endangered species. In order to address this problem, a meta-analysis aiming to examine the completeness of mtDNA haplotype sampling in recent studies of M. lutreola inter-population genetic diversity was conducted. The analysis was performed using the sample-size-based rarefaction and extrapolation sampling curve method for three populations—the Northeastern (Russia, Belarus and Estonia), the Western (France and Spain), and the Southeastern (Romania). The extrapolated values of the Shannon–Wiener index were determined, assuming full sample coverage. The gap between the measured and predicted inter-population genetic diversity was estimated, indicating that the identified level of sample coverage was the lowest for the NE population (87%), followed by the SE population (96%) and the W population (99%). A guide for sampling design and accounting for sampling uncertainty in future population genetic studies on European mink is provided. The relatively low sample coverage for the Russian population clearly indicates an urgent need to take conservation measures for European mink in this country.

Comparative Pathology of Domestic Pigs and Wild Boar Infected with the Moderately Virulent African Swine Fever Virus Strain "Estonia 2014".

Endemically infected European wild boar are considered a major reservoir of African swine fever virus in Europe. While high lethality was observed in the majority of field cases, strains of moderate virulence occurred in the Baltic States. One of these, “Estonia 2014”, led to a higher number of clinically healthy, antibody-positive animals in the hunting bag of North-Eastern Estonia. Experimental characterization showed high virulence in wild boar but moderate virulence in domestic pigs. Putative pathogenic differences between wild boar and domestic pigs are unresolved and comparative pathological studies are limited. We here report on a kinetic experiment in both subspecies. Three animals each were euthanized at 4, 7, and 10 days post infection (dpi). Clinical data confirmed higher virulence in wild boar although macroscopy and viral genome load in blood and tissues were comparable in both subspecies. The percentage of viral antigen positive myeloid cells tested by flow cytometry did not differ significantly in most tissues. Only immunohistochemistry revealed consistently higher viral antigen loads in wild boar tissues in particular 7 dpi, whereas domestic pigs already eliminated the virus. The moderate virulence in domestic pigs could be explained by a more effective viral clearance.

Organic-walled microfossils in the Ediacaran of Estonia: Biodiversity on the East European Platform

Precambrian organic-walled microfossils are not only a source for studying evolution but also increasingly associated with stratigraphic correlation, based on key fossils and assemblage composition. For this reason, two drill cores from north-eastern Estonia have been studied for their content and stratigraphic distribution of organic-walled microfossils (OWM), analysing samples from the Precambrian Gdov, Kotlin, and Voronka formations. The recovered assemblages are generally well-preserved and diverse consisting of abundant sphaeromorphs, such as Leiosphaeridia spp. and Pterospermopsimorpha spp., filamentous cyanobacteria, e.g. Cephalonyx geminatus and Palaeolyngbya catenata, and different types of cellular/colonial aggregates. In contrast, acanthomorphic acritarchs are rare with only a few unidentified examples present. The presence of taxa such as Pomoria rhomboidalis and Primoflagella speciosa in combination with the absence of large acanthomorphs suggests a late Ediacaran age of the studied samples. All in all, 38 species within 22 different genera are described herein, as are 9 taxa of unknown taxonomic affiliation. Another 11 taxa are briefly mentioned and depicted in order to provide for a better overview of the diversity of the assemblage. The stratigraphic distribution of the recognized taxa and assemblages can provide a powerful tool for correlation on the East European Platform as well as between Baltica and other palaeogeographic regions during the Ediacaran.

Lithogeochemistry and depositional environments of sedimentary rocks of the upper Vendian and lower Cambrian of the North-West Baltic monocline

«Вестник Санкт-Петербургского университета. Науки о Земле» — научно-теоретический рецензируемый журнал, обобщающий результаты исследований в области геологии, гидрогеологии и геохимии, петрологии и экологии, ландшафтного планирования и геоморфологии, экономической и социальной географии.

Why Isn’t Latvia the “Next” Crimea? Reconsidering Ethnic Integration

In the aftermath of Russia's military incursion in Ukraine and the annexation of Crimea in 2014, a flurry of articles predicted the next territorial conquest of President Vladimir Putin's Russian revanchism. High on the list were the Baltic countries, which sit precariously on the edge of Europe and historically have been the “bloodlands” between East and West in author Timothy Snyder's phrasing. More specifically, journalists and analysts pointed to the “Russian enclaves” in northeastern Estonia and southeastern Latvia, where, by many accounts, large ethnic Russian populations were prepared to rise up against Baltic governments with a bit of provocation from across the eastern border. However, six years on, there is little indication that Russian speakers in the Baltic countries are on the brink of causing an internal uprising. While there are multiple factors that can help explain the Baltic “dog that didn’t bark,” this essay considers an often overlooked variable in the equation: the depth of civic and cultural integration among Russian speakers in Latvia.

Magnetic anomaly of the Jõhvi iron ore, northeastern Estonia, controlled by subvertical remanent magnetization

Magnetic anomaly of the Jõhvi iron ore, northeastern Estonia, controlled by subvertical remanent magnetization

Mutual contacts and lexical relations among the Finnic varieties of western Ingria and northeastern Estonia

The aim of this article is 1) to describe the historical language contact situation between the genetically closely related Finnic varieties of western Ingria, 2) to give examples of the numerous loanwords originating from mutual contacts among local Finnic varieties as well as areal diffusion, and 3) to discuss the method of investigating contacts and borrowing among closely related varieties. The data are taken from old dialectal materials published in vocabularies and dictionaries as well as preserved in archives. The words that are analysed and discussed etymologically in more detail are drawn from Vote, Ingrian, and Estonian. Although it is often difficult to confirm the direction of borrowing among closely related varieties, I seek to determine the direction of diffusion in the varieties whose development cannot be described merely in terms of a traditional binary family tree model. Examples of mutual borrowing between Vote, Ingrian, Estonian, and Finnish are presented. Estonian loanwords in Vote and Ingrian can usually be recognised by their distribution. Most vocabulary originating as loans (in Vote, Ingrian, and Estonian) has been borrowed from Finnish. Loans in both Vote and Estonian often have a distribution not only in Ingrian but also in Finnish. Because of the phonetic similarity of these varieties, the donor variety usually cannot be defined. Vote loanwords occur only sporadically in Ingrian and Estonian: they may also form a substratum.
 The speakers of Finnic varieties in western Ingria used to live in old rural communities with long-term multilingualism, villages with a mixed population, and vague language boundaries. The arrival of new inhabitants from the countries, which ruled this area and the foundation of St. Petersburg in 1703 changed the ethnographic balance between different peoples in Ingria. This increased linguistic diversity and altered the hierarchy of the languages leading gradually to accelerating language and identity shift of the local peoples of Ingria.

Spatio-temporal variability and seasonal dynamics of snow cover regime in Estonia

Climate warming influences highly on snow cover regime in the midlatitudes. Snow cover conditions, in turn, affect human activity very much. The aim of this study was (a) to analyse spatial and temporal variability of snow cover duration, (b) to analyse spatial and temporal variability of the start and end dates of the period with the permanent snow cover, (c) to describe spatial, temporal and seasonal variability of median and maximum snow depth in Estonia and (d) to determine the presence of long-term changes and trends in these parameters during the period 1950/51–2015/16. Time series of daily snow depth at 22 stations for that period were processed in order to obtain reliable estimates of changes in the snow regime. Snow cover data are non-normally distributed, therefore, median and quartile range were used to describe the mean state and variability of snow cover. Only these dates were included into the analysis when snow cover was observed at least on 50% of days in the time series. Trend analysis was made using the Mann-Kendall test and trend values were found using the Theil-Sen’s method. A large spatio-temporal variability of snow cover duration was found. The median number of days with snow cover at the 22 stations was 112, varying between 61 and 130 days. In the coastal regions of Estonia and especially on the western coast of Saaremaa Island snow cover duration has been much lower than in the continental part. The longest snow cover period is observed on uplands in south-eastern and north-eastern Estonia. It was found that, in the average, the period with the permanent snow cover in the continental Estonia begins on 19 December and ends on 18 March. There was a negative trend in snow cover duration due to the earlier snow melting in spring at the majority of stations. The end date of the permanent snow cover has shifted earlier by 10–30 days in 66 years and its duration has decreased accordingly. The maximum snow depth has been recorded on uplands of south-eastern Estonia with the median value 38 cm. There was a decreasing multiannual trend in snow depth from January to the end of March. Changes in snow depth were largest in the end of February and in March when the trend was statistically significant. In the average, snow depth has decreased by 0.5–1.5 cm per decade, i.e. by 2–9 cm throughout the whole study period.

Kinetics of phenol degradation by selected bacterial strains with different genetic properties

The major environmental problem in the northeastern Estonia is the semi-coke mounds in oilshale industry areas, Alternatives to the chemical methods (sorption, ozonation) for removingxenobiotic compounds from leachate are biological methods, like bioaugmentation, where theproperly selected microorganisms are used. Determination of the kinetic constants (maximumspecific growth rates (µmax), lag times (A.), half saturation constants (Kso for oxygenatingactivity and Ksa for growth) and inhibition constants (Ki)) will give us information about therate of pollutant degradation and is the basis for the selection of the most effective bacteria forbioaugmentation. In phenol degradation the initial and rate-limiting enzyme is phenolhydroxylase, encoded by different genes, The aim of this work was to carry out a kineticstudy of the aerobic degradation of phenol using single strains (Pseudomonas mendocinaPC 1, P. fluorescens PC 18, PC20 and PC24) isolated from river water continuously pollutedwith phenolic compounds, The strains PC 1 and PC 18 contain genes for multicomponentphenol hydroxylase, whereas single-component phenol hydroxylase (pheBA operon)characterizes the strains PC20 and PC24, The phenol-oxygenating activity (Kso) was obtainedfrom substrate-dependent oxygen uptake data (oxygen concentrations were measured with aClark-type oxygen electrode) using Michaelis-Mentens model. Specific growth rates µ andlag times). were calculated from absorbance growth curves on phenol concentrations 0,2-10.6mM and the growth kinetic constants (µmax, Ksa, Ki) were estimated using Haldanes, Edwardsand Aiba-Edwards model. The Kso values for phenol were one order of magnitude lower instrains PC 1 and PC 18 than in strains PC20 and PC24.

Between sustainability, social cohesion and security. Regional development in North-Eastern Estonia

In 2012, the European Parliament (EP) established Sulphur Emission Control Areas (SECA) in Northern Europe comprising the North Sea, the Baltic Sea and the English Channel where from 2015 ships are obliged to use bunker fuel with a sulphur content not exceeding 0.1%. Estonia is a maritime fuel producer due to its oil shale reserves in the North-Eastern parts of the country (Ida-Virumaa County). A large part of oil shale is used for the production of maritime bunker oil. Unfortunately, the sulphur content of oil shale is higher than it is allowed by the SECA regulations. The Estonian oil shale industry represents up to 5% of the national economy and plays an important role in a weakly developed Ida-Virumaa County, which shares a common border with Russia and hosts the majority of Russian-speaking Estonians. Approximately half of this regional workforce is employed directly or indirectly in this industry giving the oil shale industry an important role in the county's economic well-being. In addition, periods of low oil prices are putting extra pressure on the oil sector, which endangers the traditional business model of the Estonian oil shale industry. The research investigates the impact of the environmental regulations in the shipping sector on the socio-economic situation in North-Eastern Estonia and discusses political consequences for the region. The paper highlights possible regional development strategies for Ida-Virumaa County and their impact on sustainability, social cohesion and security issues in the context of the integration of Russian speaking Estonians into the Estonian society. Methodically, the research is based on expert interviews, a survey, a case study, and a further exploration of potential political options to improve the social coherence in North-Eastern Estonia.

Deletion at the 5\u2019-end of Estonian ASFV strains associated with an attenuated phenotype

African swine fever (ASF) was introduced into the Eastern European Union in 2014 and led to considerable mortality among wild boar. In contrast, unexpected high antibody prevalence was reported in hunted wild boar in north-eastern Estonia. One of the causative virus strains was recently characterized. While it still showed rather high virulence in the majority of experimentally infected animals, one animal survived and recovered completely. Here, we report on the follow-up characterization of the isolate obtained from the survivor in the acute phase of infection. As a first step, three in vivo experiments were performed with different types of pigs: twelve minipigs (trial A), five domestic pigs (trial B), and five wild boar (trial C) were inoculated. 75% of the minipigs and all domestic pigs recovered after an acute course of disease. However, all wild boar succumbed to infection within 17 days. Representative samples were sequenced using NGS-technologies, and whole-genomes were compared to ASFV “Georgia 2007/1”. The alignments indicated a deletion of 14560 base pairs at the 5’ end, and genome reorganization by duplication. The characteristic deletion was confirmed in all trial samples and local field samples. In conclusion, an ASFV variant was found in Estonia that showed reduced virulence.

Hazardous radioactivity levels and heavy mineral concentrations in beach sediments of Lake Peipsi, northeastern Estonia

Abstract The present study discusses results of heavy mineral analyses and radioactivity of beach sediments of Lake Peipsi. Such analyses are commonly done globally, but had not yet been conducted for the fourth largest lake in Europe. The average heavy mineral content in Lake Peipsi beach sediments along the northern and western coast is higher than usual for Estonian coastal and Quaternary sediments. Concomitantly, elevated radioactivity levels have been measured in several places, with the highest concentrations observed at Alajõe (1885.5 Bq/kg), which is over five times more than the recommended limit. The aim of the present study is to find sites with higher radioactivity levels, because the northern coast of Lake Peipsi is a well-known recreational area.

Biological characterization of African swine fever virus genotype II strains from north-eastern Estonia in European wild boar.

Due to its impact on animal health and pig industry, African swine fever (ASF) is regarded as one of the most important viral diseases of pigs. Following the ongoing epidemic in the Transcaucasian countries and the Russian Federation, African swine fever virus was introduced into the Estonian wild boar population in 2014. Epidemiological investigations suggested two different introductions into the southern and the north-eastern part of Estonia. Interestingly, outbreak characteristics varied considerably between the affected regions. While high mortality and mainly virus-positive animals were observed in the southern region, mortality was low in the north-eastern area. In the latter, clinically healthy, antibody-positive animals were found in the hunting bag and detection of virus was rare. Two hypotheses could explain the different behaviour in the north-east: (i) the frequency of antibody detections combined with the low mortality is the tail of an older, so far undetected epidemic wave coming from the east, or (ii) the virus in this region is attenuated and leads to a less severe clinical outcome. To explore the possibility of virus attenuation, a re-isolated ASFV strain from the north-eastern Ida-Viru region was biologically characterized in European wild boar. Oronasal inoculation led to an acute and severe disease course in all animals with typical pathomorphological lesions. However, one animal recovered completely and was subsequently commingled with three sentinels of the same age class to assess disease transmission. By the end of the trial at 96days post-initial inoculation, all animals were completely healthy and neither virus nor viral genomes were detected in the sentinels or the survivor. The survivor, however, showed high antibody levels. In conclusion, the ASFV strain from north-eastern Estonia was still highly virulent but nevertheless, one animal recovered completely. Under the experimental conditions, no transmission occurred from the survivor to susceptible sentinel pigs.