Search Results (15)

The rehabilitation of coal mine sites in semi-arid environments is a step in combating desertification. A promising rehabilitation approach involves the development of anthropic soils that can support vegetation. However, reliable soil quality indicators are needed to evaluate long-term sustainability of rehabilitation strategies. In a coal mine area in northeastern Spain, two anthropic soils (0.5 m thick) were constructed by layering fine-textured coal residues at the bottom, topped with coarse overburden materials. Chemical fertility was enhanced using combinations of semi-liquid manure (25 or 60 mm) and straw (0 or 15 Mg ha⁻¹), resulting in four treatments randomly distributed across both soil surfaces. Two abiotic indicators were selected for sustainability assessment: soil organic carbon (SOC) fractions and microstructure. Seven years after rehabilitation activities were completed, SOC fractions were analyzed. In addition, two years later, soil porosity and specific pore perimeter were also assessed in soil thin section images. The results indicated that the lower manure rate promoted more efficient SOC stabilization, evidenced by a 4–5-fold increase in specific pore perimeter at 0–5 cm depth, and lower fulvic acid content at 5–20 cm depth, compared with the higher manure rate. Micromorphological analysis proved to be a sensitive method for detecting early improvements in the physical quality of anthropic soils, highlighting the importance of adjusting manure rates for sustainable coal mine rehabilitation. Full article

Soil reflects ecosystem processes and is influenced by gradual biospheric changes, which can affect its biotic components. In fairy rings, soil morphology, physicochemical properties, and biota are interconnected within a shared environmental space. In La Bertolina grasslands, while fungal and bacterial genomics have been investigated, the micromorphological soil effects of these rings have not. This study micromorphologically analyzed thin sections of three fairy rings at four zones: the ring center, the zone of peak growth in 2013 (R13), the predicted growth zone for 2019 (R19), and outside the ring. From each zone, two thin soil sections were prepared, totaling 24 samples. Fungal structures were exhaustively described according to morphological criteria following reference by multiple authors. The soil was a calcareous, loamy Regosol, and showed moderately developed crumb or laminar microstructures. Nine types of fungal structures were identified, consistent with genomic findings in the zone. Although fungal abundance did not vary across zones, mesofauna droppings were more frequent in R13 and R19, which was related to higher nutrient or water availability due to the fungal activity. Regarding the groundmass of the topsoil, neither the composition nor the microstructure of the surface horizons varied according to the moment of appearance of the ring at the sampled points. Full article

The water level of Lake Neuchâtel (Switzerland) was lowered 150 years ago, initiating soil formation and colonization by riparian forests of the previously submerged areas. Although the soils of the whole area are young and have probably quite similar parent material (lacustrine sediments and moraine), the present soils show a large diversity of horizon structures and contents. The aim of this study is to describe the respective processes of accumulation, integration, and stabilization of organic matter and assess the soil variables influenced by these processes in the various types of riparian forests with different moisture levels. The investigation employed a semi-quantitative, holistic approach that combined field observations, laboratory analyses, and micromorphological examination of soil thin sections. The results indicate that the accumulation and stabilization of organic matter are primarily governed by physicochemical factors associated with the parent material, particularly soil texture and calcium cation saturation. Soil moisture and groundwater elevation were found to mainly influence biological activity and vegetation types. Additionally, the incorporation of organic matter is affected by both soil texture and bioturbation processes. Overall, this study underscores the complexity of the mechanisms regulating organic matter dynamics in young soils. Full article

The process of anthropogenic pedogenesis has necessarily become an important aspect of the study of today’s soils. The sustainable reclamation or remediation of soils degraded by industrial or mining activities is currently of great interest worldwide. In this field, the study of thin soil sections can provide relevant answers, particularly to questions concerning the evolution of these soils under the impact of reclamation practices. Here, we describe an experiment to reclaim former rare earth element mining sites in China using organic soil amendments and plantations of a local fiber plant, Boehmeria nivea. Two years after the start of the experiment, a study of soil structure, considered as an indicator of soil biofunctioning, was carried out on the different plots, supplemented by monitoring of physico-chemical properties. Morphological (light microscopy) and analytical (SEM-EDX, µ-XRF) characterization of thin sections allowed us to pinpoint some pedological processes as aggregation with particular reference to the contribution of biological factors and mineral species, highlighting the impact of the practices implemented. Using a soil micromorphology approach enabled us to track the rapid evolution of the early stages of pedogenesis of these Technosols and to provide insight into the potential for reclamation of these mined sites in the future. Full article

The Chernevaya taiga is a unique ecosystem formed under the influence of a complex of geogenic and bioclimatic factors located in the foothill border of the southeastern part of Western Siberia. The combination of local climatic conditions and the composition of parent material led to the formation of specific soil conditions on the territory of these habitats. The soils of the Chernevaya taiga have unique morphogenesis. They have a thick podzolized horizon and are fertile, unlike the typical soils of the oligotrophic pine forests of Siberia; however, the microstructure of these soils is poorly studied. The purpose of the research is to analyze the micromorphological organization and microstructure of three types of soils in Western Siberia (two typical soils from the Chernevaya taiga (Greyzemic Phaeozem (Albic) and Albic Stagnic Luvisol (Ochric)) and one from oligotrophic pine stand (Eutric Protoargic Arenosol)). It was found that the soils of the Chernevaya taiga differ greatly from the background (zonal) soils of the region on both the macro- and microlevels. In the Phaeozems and Luvisols of the Chernevaya taiga, there are actively formed organomineral aggregates and the quantity of porous media is more than 50%. At the bottom of the podzolized part of the soil profiles, we noted illuvial processes and a sharp change in the type of microstructure. The presence of pyrogenic materials (charcoal) and coprolitic (vermicular) materials in the humus-accumulative horizon indicates a high rate of material transformation and high biological activity and bioturbation in the soil. The skeleton part of the Chernevaya taiga soils is represented by a quartz–feldspar base with an admixture of sericite; augite; biotite; and a minimal admixture of tourmaline, zircon, and glauconite. Full article

Females of frog-biting midges (Corethrellidae) obtain their blood meals from male calling frogs. While the morphology of the feeding apparatus is well studied in hematophagous Diptera that impact humans, frog-biting midges have received far less attention. We provide a detailed micromorphological examination of the piercing blood-sucking proboscis and maxillary palpus in three Corethrella species using scanning electron microscopy and histological semi-thin sectioning. We also compare the sensilla found on the proboscis tip and the palpus of Corethrella with other piercing blood-sucking Diptera. Corethrella spp. have a proboscis length of about 135 µm, equipped with delicate mandibular piercing structures composing the food canal together with the labrum and hypopharynx. Their proboscis composition is plesiomorphic and more similar to other short-proboscid hematophagous Culicomorpha (e.g., Simuliidae), in contrast to the phylogenetically more closely related long-proboscid Culicidae. As in other short-proboscid taxa, the salivary canal in Corethrella spp. transitions into an open salivary groove with one mandible forming a seal, whereas in Culicidae the salivary canal is closed until the tip of the proboscis. We discuss the possible functional constraints of very short, piercing blood-sucking proboscises (e.g., dimensions of host blood cells) that may limit the size of the food canal. Full article

The investigation of fires and burning within the archaeological record has a long history, and the applied methods are diverse. There have been several investigations of prehistoric archaeological sites, but Middle Bronze Age contexts (2000–1450 BC) of the Carpathian Basin have not been widely studied beyond studies of ritual burning or warfare. In this paper, we aimed to add further details to this topic in the household context via thin-section soil micromorphology and related phytolith and charred plant matter analysis. The combination of these techniques has been proven to be advantageous due to their high-resolution quality, but phytolith analysis of soil/sediment via thin sections (i.e., in fixed environment) has not been largely explored yet. In this study, these methods were used to investigate various burning events that affected a Middle Bronze Age Vatya house within the tell site of Százhalombatta-Földvár, Hungary. Three types of fire/burning events were investigated. One was related to hearth activity, another one to a presumed ‘cleaning’ of the house, and the last one to the termination of the building. In the first two cases, everyday life was under the microscope; the latter was more enigmatic, and probable intentional destruction was demonstrated. Full article

The rumen is an important hallmark organ of ruminants and plays an important role in the metabolism and immune barrier of Tibetan sheep on the Plateau. However, there are few studies on rumen development and metabolism regulation in Tibetan sheep at different ages. Here, we comprehensively analyzed the immune function, fermentation function, rumen epithelial micromorphology and transcriptome profile of Tibetan sheep at different ages. The results showed that the concentration of IgG decreased and the concentration of IgM increased with age (p < 0.05), and the highest concentration of IgA was observed at 1.5 and 3.5 years of age. In terms of rumen fermentation characteristics, VFAs of 4-month-old lambs were the highest, followed by VFAs and NH₃-N of Tibetan sheep at 3.5 years of age. Hematoxylin-eosin staining and transmission electron microscopy section examination of rumen epithelial tissue showed that the rumen papilla width increased with age (p < 0.001), the thickness of the stratum corneum decreased, the cells in the stratum corneum showed accelerated migration and the thickness of the rumen muscle layer increased (p < 0.001). Desmosomal junctions between the layers of rumen epithelium increased at 1.5 and 3.5 years old, forming a compact barrier structure, and the basal layer had more mitochondria involved in the regulation of energy metabolism. RNA-seq analysis revealed that a total of 1006 differentially expressed genes (DEGs) were identified at four ages. The DEGs of Tibetan sheep aged 4 months and 6 years were mainly enriched in the oxidation–reduction process and ISG15-protein conjugation pathway. The 1.5 and 3.5-year-olds were mainly enriched in skeletal muscle thin filament assembly, mesenchyme migration and the tight junction pathway. WGCNA showed that DEGs related to rumen microbiota metabolite VFAs and epithelial morphology were enriched in “Metabolism of xenobiotics by cytochrome P450, PPAR signaling pathway, Butanoate metabolism pathways” and participated in the regulation of rumen epithelial immune and fermentation metabolism functions of Tibetan sheep at different ages. This study systematically revealed the regulatory mechanism of rumen epithelial development and metabolism in the plateau adaptation of Tibetan sheep, providing a new approach for the study of plateau adaptation. Full article

The assessment of the micromorphological characteristics of soils is a powerful tool for studying the transformation of soils under the influence of various weathering mechanisms (physical, biogenic). The central part of Yakutia is characterized by a large area of agricultural lands, some of which has become fallow land and is subject to cryogenic processes, fires and anthropogenic impact. Under the conditions of climate change, the fallow soils of Yakutia can be re-involved in the agricultural complex. To study their state, a method of micromorphological investigation of thin soil sections is proposed. Thin sections of soils were analyzed using a polarizing microscope Leica DM750P. As a result of the work, zonal, fallow, pyrogenic and agricultural soils of the central part of Yakutia were analyzed. The soils were found to be in a degraded state. Zonal soils were characterized by the presence of quartz grains, feldspar, and undecomposed plant tissue, as well as biogenically transformed humus. Fallow soils were characterized by a thick organo-mineral (A) horizon, quartz grains, feldspar, and silty-clay plasma. Pyrogenic soils have differences from natural and fallow soils; as a result of fires and active illuviation of organo-mineral substances. The Anthrosol soils were characterized by a large number of aggregates of various sizes. In their composition there were various minerals, such as quartz, feldspar and mica. The signs of soil cryogenesis were noted only in the underlying horizons (B), while the upper horizon (A) had no signs of cryogenic transformation. Full article

The distinctive features of floral nectaries facilitate identification of ecological and phylogenetic links between related taxa. The structure and functioning of nectaries determine the relationships between plants, pollinators, and the environment. The aim of the study was to determine and compare the micromorphology of the epidermis in the floral nectaries of six Rubus idaeus cultivars belonging to biennial (‘Glen Ample’, ‘Laszka’, ‘Radziejowa’) and repeated fruiting (‘Pokusa’, ‘Polana’, ‘Polka’) groups. Another objective was to characterize the cuticle ornamentation and stomatal morphology, the anatomy of the nectary epidermis, parenchyma, and sub-nectary parenchyma in the initial nectar secretion phase, as well as the ultrastructure of the nectary epidermis and parenchyma cells in the initial and full nectar secretion phases. The study was carried out using light, fluorescence, scanning and transmission-electron microscopy techniques. Semi-thin and ultrathin sections were used for the microscopic analyses. The cuticular ornamentation and stomatal morphology may be helpful elements in the identification of relatedness between Rubus species. The interaction of the extensive system of endoplasmic reticulum membranes, mitochondria, and Golgi apparatus indicates high metabolic activity, and the fusion of transport vesicles with the membrane suggests granulocrine nectar secretion. The results bring new data to the biology of plants. Full article

Micromorphological investigation of soils is a powerful tool for studying the transformation of soils under the influence of various weathering mechanisms. In the Arctic region, under the influence of seasonal freezing/thawing processes, cryohydration is the leading type of weathering. Soils of different-aged islands of the Lena River Delta were investigated. Thin sections of soils were analyzed using a polarizing microscope Leica DM750P (Leica Camera AG, Wetzlar, Germany). X-ray fluorescence analysis was used to determine the chemical composition of the soils. As a result of the work, the rate of weathering of soil minerals was estimated, soil fabric was considered, as well as the chemical composition of the soil. The accumulation of poorly sorted circular striated sand due to active influence of the Lena River was noted on young soil from Samoylov isl. The formation of biogenic sand-silt crumb aggregates was noted at more ancient sites. Physical weathering of soil minerals under the influence of cryogenic processes has been noted. Full article

Human communities at the transition between the Eneolithic period and the Bronze Age had to rapidly adapt to cultural and climatic changes, which influenced the whole Mediterranean. The exact dynamics involved in this crucial passage are still a matter of discussion. As newer studies have highlighted the key role of climatic fluctuations during this period, their relationship with the human occupation of the landscape are yet to be fully explored. We investigated the infilling of negative structures at the archaeological site of Tegole di Bovino (Apulia, Southern Italy) looking at evidence of the interaction between climate changes and human strategies. The archaeological sedimentary deposits, investigated though geoarchaeological and micromorphological techniques, show the presence of natural and anthropogenic infillings inside most structures. Both human intervention and/or natural events occurred in the last phases of occupation of the site and its subsequent abandonment. The transition to unfavorable climatic conditions in the same period was most likely involved in the abandonment of the site. The possible further impact of human communities on the landscape in that period, testified by multiple other archives, might have in turn had a role in the eventual change in land use. Full article

Acromyrmex fracticornis grass-cutting ants construct conspicuous chimney-shaped nest turrets made of intermeshed grass fragments. We asked whether turrets are constructed by merely piling up nearby materials around the entrance, or whether ants incorporate different materials as the turret develops. By removing the original nest turrets and following their rebuilding process over three consecutive days, age-dependent changes in wall morphology and inner lining fabrics were characterized. Micromorphological descriptions based on thin sections of turret walls revealed the building behaviors involved. Ants started by collecting nearby twigs and dry grass fragments that are piled up around the nest entrance. Several large fragments held the structure like beams. As a net-like structure grew, soil pellets were placed in between the intermeshed plant fragments from the turret base to the top, reinforcing the structure. Concomitantly, the turret inner wall was lined with soil pellets, starting from the base. Therefore, the consolidation of the turret occurred both over time and from its base upwards. It is argued that nest turrets do not simply arise by the arbitrary deposition of nearby materials, and that workers selectively incorporate large materials at the beginning, and respond to the developing structure by reinforcing the intermeshed plant fragments over time. Full article

Tana di Badalucco cave is located in Imperia (Liguria, Italy), not far from the French border. This site is scarcely known and it has never been studied accurately, even though different archaeological excavations have returned really important elements, both in the archaeological and the paleoenvironmental aspects. Its stratigraphy ranges from Middle Paleolithic to Metal Ages, thus it has registered important climate and environmental variations specific to the Upper Pleistocene and Holocene. From 2012, the Soprintendenza Archeologia della Liguria, the Museo di Archeologia Ligure, and DiSTAV (University of Genova) have been collaborating in order to finally study this promising and complex stratigraphy, trying to reconstruct the paleoenvironmental context of the region. In this work, we present what we were able to assess thanks to the use of micromorphology, the study of undisturbed thin soil sections. This technique has proven useful in recognizing the alternating of cold and warmer conditions during the Quaternary, as well as in identifying primitive signs of human and animal occupation. Full article

Short-term variations of soil conditions affect the form, mobility and bioavailability of metal pollutants. Released metals migrate toward depth where they are intercepted or precipitate, leading to variable spatial metal distribution patterns, at a macro-, meso- and microscale. Studies at a mesoscale give access to trace metal (TM) associations induced by pedological processes. Although scarcely documented, such meso-scale studies represent an essential step for relevant environmental risk assessment, halfway between field- and molecular-scale investigations. We argued for such approach by performing optical microscopy and micro-X-ray fluorescence on thin sections from two soils, contaminated either by industrial zinc-smelter waste or by urban wastewater. Consistent correlation between key indicators of pedological processes (Fe, Mn, and Ca) and trace metals (Zn, Pb, and Cu) on some 20 elemental maps of TM-hosting soil constituents and pedofeatures reveal distinct coinciding localizations, illustrating TM-accumulation via interception or (co)-precipitation processes. Micromorphological interpretation of characteristic pedofeatures in subsurface horizons (crystals, argillans, ferrans, and mangans) containing significant amounts of TM provide valuable insight into the contaminant dynamics in terms of lixiviation, colloidal transport, redox conditions, or fungal activity. Our mesoscale approach stresses the importance of pedology-based sampling strategies, instead of systematic soil-depth sampling, for soil contamination research in natural ecosystems. Full article