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This paper presents the authors’ research results from an analysis of intermediate foundations as well as slab and pile foundations in the context of soil consolidation. Looking at soil as a building material that changes its properties over time is very important from the point of view of the safety of construction, implementation, and operation of building structures. In addition, soil can be parameterized in such a way as to accurately describe its possible behavior under service loading. Of great interest is the phenomenon of consolidation, which is based on the reduction of soil volume over time under constant loading. This study explores existing piles and replicates soil conditions to understand individual and grouped pile behavior in combined pile–raft foundations (CPRF). To assess pile settlement from primary and secondary consolidation phases, 13 field measurements on concrete columns in gyttja clay were conducted. Analyzing data from these tests allowed engineers to accurately calibrate a numerical model. This calibrated model was instrumental in designing high-rise buildings, ensuring stability and safety. This study emphasizes the importance of understanding soil behavior, particularly consolidation phenomena, in optimizing foundation design and construction practices.

The aim of this study is to characterize the current spatial distribution of three main phyla of phytoplankton (Cyanobacteria, Charophyta and Chlorophyta) from 77 Latvian lakes and ponds, analysed from modern surface sediment samples through a non-pollen palynomorph approach. The Pearson cross-correlation and the principal component analysis were applied to test the potential correlation of phytoplankton with climate (mean winter and summer temperature), water (pH), environmental (land use â forest, agriculture and urban) and sediment (organic and carbonate matter) variables. The results show the dominance of Chlorophyta in Latvian lakes and ponds. Cyanobacteria were dominant in sites closer to human-populated and recreation centres, including urban and agricultural land-use areas. In more turbid and polluted environments, Chlorophyta thrive today. Charophyta dominated in forested areas. Although Chlorophyta dominate in present-day waterbodies, the rather high relative proportion of Cyanobacteria draws attention to a potential threat. As the cross-correlation results indicate a negative correlation between Cyanobacteria and mean winter temperatures, in warmer climates Cyanobacteria can overtake other phytoplankton. The results of this study can be further used in lake and pond management.

Introduction: The increased adoption of proximal sensors has helped to generate peat mapping products: they gather data quickly and can detect the peat-mineral later boundary. A third layer, made of sedimentary peat (limnic layers, gyttja), can sometimes be found in between them. This material is highly variable spatially and is associated with degraded soil properties when located near the surface. Methods: This study aimed to assess the potential of direct current resistivity measurements to predict the maximum peat thickness (MPT), defined as the nonlimnic peat thickness, to facilitate soil conservation andmanagement practices at the field-scale. The results were also compared to a regional map of the MPT from a previous study used and also tested as a covariate. This study was conducted in a shallow (MPT = 8-138 cm) cultivated organic soil from Québec, Canada. The MPT was mapped using the apparent electrical conductivity (ECa) from a Veris Q2800, and a digital elevation model, with and without a regional MPT map (RM) as a covariate to downscale it. Three machine-learning algorithms (Cubist, Random Forest, and Support Vector Regression) were compared to ordinary kriging (OK), multiple linear regression, and multiple linear regression kriging (MLRK) models. Results and discussion: The best predictive performance was achieved with OK (Lin's CCC = 0.89, RMSE = 13.75 cm), followed by MLRK-RM (CCC = 0.85, RMSE = 15.7 cm). All models were more accurate than the RM (CCC = 0.65, RMSE = 29.85 cm), although they underpredicted MPT > 100 cm. Moreover, the addition of the RM as a covariate led to a lower prediction error and higher accuracy for all models. Overall, a field-scale approach could better support precision soil conservation interventions by generatingmore accuratemanagement zones. Future studies should test multi-sensor fusion and other geophysical sensors to further improve the model performance and detect deeper boundaries. [ABSTRACT FROM AUTHOR]

This paper presents the authors' research results from an analysis of intermediate foundations as well as slab and pile foundations in the context of soil consolidation. Looking at soil as a building material that changes its properties over time is very important from the point of view of the safety of construction, implementation, and operation of building structures. In addition, soil can be parameterized in such a way as to accurately describe its possible behavior under service loading. Of great interest is the phenomenon of consolidation, which is based on the reduction of soil volume over time under constant loading. This study explores existing piles and replicates soil conditions to understand individual and grouped pile behavior in combined pile–raft foundations (CPRF). To assess pile settlement from primary and secondary consolidation phases, 13 field measurements on concrete columns in gyttja clay were conducted. Analyzing data from these tests allowed engineers to accurately calibrate a numerical model. This calibrated model was instrumental in designing high-rise buildings, ensuring stability and safety. This study emphasizes the importance of understanding soil behavior, particularly consolidation phenomena, in optimizing foundation design and construction practices. [ABSTRACT FROM AUTHOR]

We present the first record of Holocene fossil insect assemblages from Central Yakutia. A stratigraphic sequence in the locality within the Vilyuy River valley is a buried oxbow. The late Holocene water body inherited an impervious stratum from the late Pleistocene. The organic layer preserved rich fossil assemblages of macrofossils including insects and other invertebrates, plants, and charcoal. The ancient flora and fauna include species that are common in Yakutia as well as those that are rare and absent in the region. The most abundant finds are leech cocoons and bogbean seeds. The macrofossils of some insects were found along with remains of their host plants. Despite the absence of intensive human land use in the area, traces of fires were recorded. The oxbow represents the environment of a floodplain wetland that developed separately from the ecosystem of the adjacent sand dunes. [ABSTRACT FROM AUTHOR]

Human‐induced activities around Lake Lilaste in the central Latvian sandy coastal area have been reconstructed over a 1300‐year period. We use a combination of well‐established geoarchaeological research methods (14C dating, pollen, nonpollen palynomorphs, REVEALS modeling, diatoms, C/N ratio, magnetic susceptibility, loss on ignition) to study the human impact on the environment. Historical context aids focus on records of resource (e.g., timber) exploitation in the area. The continuous record of human indicator pollen and agricultural landscape suggests this area was suitable for habitation well before the studied time period, likely due to the ecosystem services it provided. Our proxy‐based study, combined with historical background, reveals a significant human impact on the terrestrial environment since the 14th century. Deficiency of trees in the northern outskirts of Riga during the 17th–19th century was likely. Anthropogenic activity has led to both deforestation and change in species composition. Our paleo records indicate recognizable human‐driven legacy in current seacoast landscape. [ABSTRACT FROM AUTHOR]

As part of paleogeographic studies on the Curonian Spit (geological section GS 024), a coastal section was studied from the sea in the area of the village of Lesnoy in the place where relict lagoon oozes come out. The granulometric, chemical, and mineral compositions of slope sands were studied for the first time. Heterogeneous conditions for the formation of sand strata were confirmed. A high probability of a secondary change in the composition of sediments as a result of weathering processes was revealed. The results of the study indicate a gradual advance of sand deposits on the coastal part of the lagoon, which began about 10 ka ago. Differentiation of the sand stratum into lower and upper parts with respect to an interlayer marker of coarse-grained sand identified in the section may reflect different stages of generation of the sand stratum: from an alleged shallow-water swell formed during sea level rise to beach and eolian sands. [ABSTRACT FROM AUTHOR]

Continuous sediment cores H1 (11.0 m long) and H2 (8.5 m long), collected from Swan Lake, in the Nebraska Sandhills (USA), contain a sandy silt interval between overlying lake gyttja and underlying marsh peat. The marsh peat is a 3-m-thick layer in core H1 and a 1.5-m-thick layer in core H2, with basal ages of ca. 4790 and 4710 cal yr BP, respectively. Peat samples contain up to ~ 61% organic matter (OM) and lack CaCO3 and opal phases. Gyttja extends from 7.6 to 0 m in core H1 and from 6.6 to 0 m in core H2, with estimated basal ages of 3480 and 3530 cal yr BP, respectively. Gyttja samples contained stratigraphically fluctuating relative amounts of OM, precipitated CaCO3, biogenic (ostracod) CaCO3, and diagenetic mineralogical aggregates with CaCO3-opal-A-opal-CT-quartz or opal-A-quartz. OM content in the gyttja ranged from 15.1 to 32.1% and bulk CaCO3 content ranged from 13.5 to 34.6%. Mineralogical aggregates appeared after ~ 2630 cal yr BP in core H1 and after ~ 2590 cal yr BP in core H2, whereas ostracods were found only after ~ 1250 and ~ 1840 cal yr BP in the two cores, respectively. The discrepancy in the timing of ostracod occurrence may be related to environmental differences at the two locations, which are ~ 100 m apart. The sandy silt interval (0.4 m thick) between the peat and overlying gyttja accumulated between ~ 3700 and 3500 cal yr BP. It has relatively low OM (10.3–15.1%) and calcite content (0–6.1%) and no ostracods or mineralogical aggregates. The sandy silt interval possessed a high clastic content (~ 88%), with up to 3.2% Fe, 0.25% Ti, 108 ppm Rb, 105 ppm Zr, 65.5 ppm Cr, 36.6 ppm La, 10 ppm Th, and 2.6 ppm U. The clastic particles and associated metals were deposited by eolian processes during a dry and windy climate episode at the onset of the late Holocene in the Sandhills region. [ABSTRACT FROM AUTHOR]

We present the first record of Holocene fossil insect assemblages from Central Yakutia. A stratigraphic sequence in the locality within the Vilyuy River valley is a buried oxbow. The late Holocene water body inherited an impervious stratum from the late Pleistocene. The organic layer preserved rich fossil assemblages of macrofossils including insects and other invertebrates, plants, and charcoal. The ancient flora and fauna include species that are common in Yakutia as well as those that are rare and absent in the region. The most abundant finds are leech cocoons and bogbean seeds. The macrofossils of some insects were found along with remains of their host plants. Despite the absence of intensive human land use in the area, traces of fires were recorded. The oxbow represents the environment of a floodplain wetland that developed separately from the ecosystem of the adjacent sand dunes.

A complex of dislocations is described (extended gently dipping faults with a displacement of up to 1 m, dipping towards the center of the lens, steep faults with displacements of 5–20 cm), liquefaction structures (angular pseudonodules of sands in silts), near fault and near-strike-slip fault folds in the section of a large lens of the Mikulinskiy lacustrine–bog sediments (interbedded silt with a horizon of peat and clayey gyttja) of the aseismic region of the Russian Plate (Klin–Dmitrov ridge) in order to compare them with similar structures of the Baltic Shield, the seismogenicity of which is being discussed. It has been shown that the sequence was not subjected to periglacial phenomena such as glaciotectonics, glaciokarst, cryogenic deformations, the presence of which and pseudomorphism along polygonal-veined ice was noted only in the roof of the Mikulinskiy interglacial complex. A model is proposed for the formation of dislocations as a result of slumping of a silt layer with uneven subsidence of the underlying layers of peat sediments, which have been strongly compacted during lithogenesis, which explains the features of the kinematics of faults. The results showed that the dislocations of the Mikulinsky complexes of the Dmitrov quarry do not fundamentally differ from similar structures of the Baltic Shield, which confirms their lithogenic or exogenic (rather than seismotectonic) genesis in both regions. The differences in the dislocation complexes of the two regions are in the different sequence of formation of liquefaction and faults structures: in the Dmitrov section, they were formed synchronously, in the sections of the Baltic Shield, asynchronously. [ABSTRACT FROM AUTHOR]

Copyright of Academic Journal of Agriculture / Akademik Ziraat Dergisi is the property of University of Ordu, Faculty of Agriculture, Academic Journal of Agriculture and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The paper presents the case study of geotechnical investigations reporting connected with expert’s opinion on undrained shear strength of organic sediments in the river valley at the north of Poland according to reinforcement methodology of c.a. 0,7 km highway embankment. Diversification of primary results caused additional research which revealed and confirmed liquid consistency of organic soils – several meters of organic and calcareous sediments – gyttja under the thin cover of peat. The main goal of the paper is a discussion on standardization of consistency of organic soils itself and additionally to point out very rare possibility of liquid consistency, finally not pointed in International Standards ISO 14688. The application of Atterberg limits in organic sediments is moot but even organic soil with water content higher than liquid limit can’t be classified and interpreted as very soft with description as soil which exudes between the fingers when squeezed in the hand. Such identification is practically impossible when it’s hard to squeeze because of gravitationally leaking through the fingers.

Copyright of Journal of Agriculture & Nature / Kahramanmaraş Sütçü İmam Üniversitesi Tarım & Doğa Dergisi is the property of Kahramanmaras Sutcu Imam Universitesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Successful peatland restoration requires a knowledge of peatland stratigraphy in order to understand the hydrological and ecological conditions under which peat formation occurred and to identify realistic objectives and measures for the specific site. So far, the ability to accurately identify peat deposits and lake sediments has been largely restricted to experts. To facilitate identification by others, we provide an identification key for common peatland deposits in Germany and introduce standardised portraits of 17 peat and six gyttja types with extensive descriptions and supporting photographs. We also provide information on the indicative value of the peatland deposits in terms of site conditions at the time of deposition.

Tea and hazelnut cultivated soils are mainly distributed in Black Sea region of Turkey. Low pH value is a primary problem for those soils; therefore, farmers apply lime once every 3-4 years to raise the pH value of soil. Gyttja is highly rich in organic matter (40.59%) and lime (45.67%), and it is a low cost and considerably abundant in Afşin-Elbistan Coal Basin (estimated reserve is around 4.8 billion tons). The aim of this study was to determine the phosphorus (P) sorption characteristics of gyttja, and its efficiency on P availability and soil's pH value. Optimum P sorption conditions (pH, temperature, particle size, amount of sorbent and shaking time) and maximum sorption capacity (b) for gyttja were determined in laboratory condition. Phosphorus was sorbed to gyttja (G1P1) based on its b value, and the experiment was set as pot experiment according to a comletely randomized factorial experimental design with five replications. Applications were control (G0P0), gyttja + P0 (G1P0), sole P (G0P1), and gyttja + P (G1P1). The b value obtained from Langmuir isotherm for gyttja was found as 1.59 mgg-1. The highest available P was obtained at treatment of (G1P1). Also, the treatment G1P1 was significantly different (p < 0.01) from the rest of the treatments. Gyttja application increased soil's pH value from 4.86 to 5.74 in a 6-month time period. Therefore, gyttja can be recommended for amending soil acidity and increasing available P contents in acid soils. Further studies should be conducted in field conditions to increase applicability of the results. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the influence of gyttja applications on some selected soil properties, leaf nutrient contents, yield and quality of hazelnut grown in an acid soil. Gyttja was applied to the soil at the rates of 20, 40 and 80 kg bush-1 along with the control. The experiment was conducted in a completely randomized design with four replications for two years in field conditions. The plant nutrient contents, lime, organic matter and pH of the soil significantly increased with increasing rates of gyttja. Leaf nutrient content, yield and kernel percentage of hazelnut increased significantly as gyttja rates increased as well. The gyttja application of 40 kg bush-1 induced a significant increase of 56% in hazelnut yield, as compared to the control. We suggested that gyttja could be used to improve soil properties and to increase yield and quality of hazelnut under soil acidity. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agriculture & Nature / Kahramanmaraş Sütçü İmam Üniversitesi Tarım & Doğa Dergisi is the property of Kahramanmaras Sutcu Imam Universitesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Several shallow lakes have been drained to make way for additional arable land or pasture in the Mazurian Lakeland (NE Poland) since the 19th century. As a result of these hydrotechnical works, the water level usually decreased by approximately 6 m. Bottom sediments of the former lakes were transformed into surface limnic soils. Part of them, developed from highly calcareous gyttja, may be called limnic rendzinas. However, the present position of these soils in the Polish Soil Classification is unclear. Where the lake has undergone a natural terrestrialisation, the gyttja is covered with peat and mursh. The raw gyttja soils differ in type of organic matter forming the topsoil horizon and are subject to further transformation, the direction of which depends on the sequence of sediments in the profile, mursh formation, mineral admixture and adjoining colluvial phenomena. Common features of all these soils are high content of calcium carbonate in the surface horizons, alkaline reaction, high groundwater level and periodical flooding. The paper presents the variability of limnic rendzinas based on many examples from the Mazurian Lakeland (NE Poland). Finally, new type additions were suggested to the next edition of the Polish Soil Classification.

The Holocene sediments in north-eastern Poland are represented by mineral (alluvial and deluvial) and mineral-organic, as well as organic soil formations - peat, mursh and gyttja. The aim of the research was to determine the total content of selected elements and to investigate the mineralogical composition of the clay fraction of various Holocene sediments in north-eastern Poland. For the study, 288 soil samples were collected and total concentrations of Ca, Mg, Na, K, P, Fe, Mn, Zn, Cu after digestion in a mixture of HClO4 and HNO3 were analysed. Mineralogical composition of the clay fraction was analysed by the X-ray diffraction method. The highest average content of Fe, Mn and Zn was found in alluvial sediments in river valleys. The lowest average Mg, K, P, Fe, Mn, and Cu content was determined in mineral sediments in the moraine landscape. The content of the elements in sediments of alluvial river valleys was positively correlated with the amount of clay fraction and, except Mn, with the amount of TOC, whereas in deluvial sediments, only the Fe content correlated with the amount of clay fraction. The highest accumulation of Mg, K, Zn and Cu was found in mineral-organic sediments, while the highest Ca was in peat and gyttja. In alluvial formations in the riverine landscape, minerals from the group of mixed-packet minerals of illite-smectite dominated, with the content of smectite packages being in the range of 60-90% S. There were also small amounts of minerals from the group of illite and kaolinite. In the moraine landscape and in the landscape of ice-dammed lake origin, illite minerals dominated in the clay fraction of deluvial sediments. The presence of smectites, illite-smectite mixed-packet minerals and pedogenic chlorites was also stated. The mineralogical composition of the clay fraction of the Holocene deluvial sediments was similar to the composition of the Pleistocene accumulation sediments. [ABSTRACT FROM AUTHOR]

The main waste generated during the thermochemical processes of biomass burning used for bioenergy production in cogeneration plants are ash and biochar which can be used as fertilizers in forestry and agriculture. However, several difficulties are attributed to possibilities of practical exploitation of ash and biochar due to the transporting, handling and mode of application. Granulation of energy generation waste has been shown in some circumstances as a cost-effective and environmentally friendly method. Production of granules (pellets) from wood ash and biochar leads to improved recycling and logistics of waste as well as helps to control and avoid undesirable environmental effects such as leaching of nutrient excess. The aim of this study was to prepare granules from wood fly ash and biochar mixed with organic-rich freshwater lake sediments (sapropel) used as a natural binder and a source of organic matter for enrichment of derived granules to be applicable as a soil improver. Characterization of raw materials and derived granules included range of physical and chemical analysis. Applied granulation technology involved homogenization of components following by extrusion and drum granulation, and the process was developed for prospective production of soil improvers. It was estimated that the most optimal mass ratio of raw materials applicable for the process of granulation is 67:100 (fly ash to sapropel) and 30:100 (biochar to sapropel) resulting in production of granules 3–8 mm in diameter. Among the characteristic parameters of granules apparent density, bulk density, compressive strength, total element content and element content by fractions was assessed. Image 1 • Optimal mass ratio for granules – 67:100 fly ash/sapropel; 30:100 biochar/sapropel. • Drum granules have higher mechanical strength and density than extruded granules. • Ash/sapropel granules are richer in elements than biochar/sapropel granules. • Production of granules ⌀ 3–8 mm is applicable for use in agriculture. • Recycling of energy production waste is important at shortage of natural resources. [ABSTRACT FROM AUTHOR]

The Ełk Lakeland (NE Poland) with the area of 263 100 ha was formed during Vistulian glaciation. More than 66% of this region was shaped during the Leszno phase, 15% during the Poznań phase, and 19% during the Pomeranian phase. There are 1854 fens which cover the area of 7.3 % of the Ełk Lakeland mesoregion. Fens have an area of 10.3 ha on average. About 82.5% of the studied fens is located on gyttja deposits, which suggests post-lacustrine origin of the wetlands. Primary the lakes had covered 11% of the Ełk Lakeland, and 6.3% was transformed into fens. Most of them (60%) was formed on organic gyttja, 16% on calcareous gyttja, and 6% on clay gyttja. About 17.5% of fens was formed as a result of paludification. The types of bedrock underlying peats differ depending on the phases of glaciation.

Plant morphological attribute has been reported to be increased through the application of organic material (Gyttja) to the soil. Snapdragons (Antirrhinum majus L.) was studied under plastic house conditions to determine the effect of two different soil depth-SH (0-20 cm and 20- 40 cm), four different gyttja doses-GD (0, 1, 2, and 3%), and three different nitrogen doses-ND (0, 140, and 280 mg kg-1) on some of the plant's morphological characters; Plant Height (PH), Fresh Weight Per Plant (FWP), Number of Leaves Per Plant(NLP), Stem Diameter(SD), Number of Branches Per Plant (NBP), Number of Flower Per Spikes (NFPS) and Flower Spike Length (FSL). The results showed that gyttja application at doses of 3%, significantly increased PH, SD, NBP, NFPS, and FSL, while FWP increased only at 2% gyttja application dose and decreased at the 3% dose. The application of 280 mg kg-1 of nitrogen significantly increased (PH, FWP, NLP, NBP, NFPS and FSL). All parameters increased at (0-20 cm) soil depth, and the GD x SH x ND interaction had a significant effect on (SD, NLP, NFPS and FSL). These results suggest that adding of gyttja with nitrogen fertilizer to the calcareous and infertile soil will enhance the morphological attributes of plants. [ABSTRACT FROM AUTHOR]

Drainage of peatlands affects the fluxes of greenhouse gases (GHGs). Organic soils used for agriculture contribute a large proportion of anthropogenic GHG emissions, and on-farm mitigation options are important. This field study investigated whether choice of a cropping system can be used to mitigate emissions of N2O and influence CH4 fluxes from cultivated organic and carbon-rich soils during the growing season. Ten different sites in southern Sweden representing peat soils, peaty marl and gyttja clay, with a range of different soil properties, were used for on-site measurements of N2O and CH4 fluxes. The fluxes during the growing season from soils under two different crops grown in the same field and same environmental conditions were monitored. Crop intensities varied from grasslands to intensive potato cultivation. The results showed no difference in median seasonal N2O emissions between the two crops compared. Median seasonal emissions ranged from 0 to 919 µg N2Om-2 h-1, with peaks on individual sampling occasions of up to 3317 µg N2Om-2 h-1. Nitrous oxide emissions differed widely between sites, indicating that soil properties are a regulating factor. However, pH was the only soil factor that correlated with N2O emissions (negative exponential correlation). The type of crop grown on the soil did not influence CH4 fluxes. Median seasonal CH4 flux from the different sites ranged from uptake of 36 µg CH4 m-2 h-1 to release of 4.5 µg CH4 m-2 h-1. From our results, it was concluded that farmers cannot mitigate N2O emissions during the growing season or influence CH4 fluxes by changing the cropping system in the field. [ABSTRACT FROM AUTHOR]

The determination of the total carbon storage of peatlands is of high relevance in the context of climate-change mitigation efforts. This determination relies on data about stratigraphy and peat properties, which are conventionally collected by coring. Ground-penetrating radar (GPR) and electrical resistivity imaging (ERI) can support these point data by providing subsoil information in two-dimensional cross-sections. In this study, GPR and ERI were conducted at two groundwater-fed fen sites located in the temperate zone in north-east Germany. The fens of this region are embedded in low conductive glacial sand and are characterised by thick layers of gyttja, which can be either mineral or organic. The two study sites are representative of this region with respect to stratigraphy (total thickness, peat and gyttja types) and ecological conditions (pH-value, trophic condition). The aim of this study is to assess the suitability of GPR and ERI to detect stratigraphy and peat properties under these characteristic site conditions. Results show that GPR clearly detects the interfaces between (i) Carex and brown-moss peat, (ii) brown-moss peat and organic gyttja, (iii) organic- and mineral gyttja, and (iv) mineral gyttja and the parent material (glacial sand). These layers differ in bulk density and the related organic matter content. ERI, however, does not delineate these layers; rather it delineates regions of varying properties. At our base-rich site, pore fluid conductivity and cation exchange capacity are the main factors that determine peat electrical conductivity (reverse of resistivity), whereas organic matter and water content are most influential at the more acidic site. Thus the correlation between peat properties and electrical conductivity are driven by site-specific conditions, which are mainly determined by the solute load in the groundwater at fens. When the total organic deposits exceed a thickness of 5 m, the depth of investigation by GPR is limited due to increasing attenuation. This is not a limiting factor for ERI, where the transition from organic deposits to glacial sand is visible at both sites. Due to these specific sensitivities, a combined application of GPR and ERI meets the demand for up-to-date information on carbon storage of peatlands, which is, moreover, very site-specific because of the inherent variety of ecological conditions and stratigraphy between peatlands in general and between fens and bogs in particular. [ABSTRACT FROM AUTHOR]

Sediments in lakes have been formed under the conditions of sensitive ecosystem functions as historical records of micro- and macrocomponents. Besides others, lake sediments preserve macroremain and chemical evidence reflecting environmental changes and human impact. During the last centuries, sediment composition has been influenced by inconsistent urban and industrial developments. This article presents the multi-proxy data obtained from studies of lake sediment composition, chemical analysis and macroremain signatures in the upper sediment layer from tree small lakes of different origin: Lake Lilaste (lagoonal), Lake Velnezers (glaciokarstic), and Lake Veveri (glacial). The studies of lake sediments revealed that human impact is recognisable in the upper sediment layer of all investigated lakes, but at different depth from the sediment surface. The most recognisable traces of anthropogenic influence can be attributed to the increase of lead (Pb), cadmium (Cd) concentration, number of plant macroremains and charcoal particles in all investigated lake sediments. [ABSTRACT FROM AUTHOR]

Reconstruction of the Holocene palaeoenvironment conditions in Southeastern Latvia is based on multiproxy records from Lake Pilvelis: pollen, plant macrofossil and microfossil analysis; loss-on-ignition (LOI) measurements; 14 C dating; humic substances content; humification index; and elemental composition of gyttja organic mass. The data complex obtained in the result of multiproxy studies of sediments in Lake Pilvelis indicates significant changes in the depositional environment during the lake development. Data from Lake Pilvelis show that the start of organic-rich sediments formation before approximately 9750 cal BP, when birch–pine forest dominated in the surrounding landscape. Diagrams and data sets show six remarkable comparatively short cooling periods during the Holocene, which are related to changes in temperature and water level and influenced values and variability of remains. The investigation recognized the 8.4 ka BP and 4.6 ka BP cold events, while other cooling events can be recognised conditionally. During the events of 4.0 ka BP, the water level decreased extremely and the climate was probably drier, indicated by the comparison of records from Lake Pilvelis, Mazais Svetinu Bog and Lake Razna. A comparison of pollen data from Lake Pilvelis with Lake Kurjanovas, Mazais Svetinu Bog and Lake Razna shows some similarities, revealing features of cooler climatic conditions approximately at the time characterised by an increase of Betula and herb pollen. [ABSTRACT FROM AUTHOR]