Sedge Peat Research Articles

Aerobic and anaerobic decomposition rates in drained peatlands: Impact of botanical composition

Drained peatlands in temperate climates are under threat from climate change and human activities. The resulting decomposition of organic matter plays a major role in regulating the associated land subsidence rates, yet the determinants of aerobic and anaerobic peat decomposition rates are not fully understood. In this study, we sought to gain insight into the drivers of decomposition rates in botanically diverse peatlands (sedge, reed, wood, and moss dominant) under oxic and anoxic conditions. Peat samples were collected from the anoxic zone and incubated for 24 h (short) and 15 weeks (long) under either oxic or anoxic conditions. CO2 emissions, hydrolytic and oxidative exoenzyme potential activities, phenolic compound concentrations, and several edaphic factors were measured at the end of each incubation period.We found that 15 weeks of oxygen exposure of anoxic peat samples accelerated the average CO2 emissions by 3.9-fold. Reed and sedge peat respired more than wood and moss peat under anoxic conditions. Interestingly, CO2 emissions from anoxic peat layers under permanently anoxic conditions were substantial and given the thickness of peat deposits in the field, such activities may play an important role in long-term land subsidence rates and total CO2 emissions from drained peatlands. The results from the long-term incubations showed that decomposition rates appear to be also controlled by factors other than oxygen intrusion such as substrate availability. In summary, the botanical composition of the peat matrix, incubation conditions and time of incubation are all important factors that need to be considered when predicting peat decomposition and subsequent land subsidence rates.

Evaluation of a Method to Induce Hydrophobicity on Sand

Methods to evaluate soil water repellency (SWR) require extensive studies on field soils and are subject to the heterogeneity of SWR throughout the soil profile as well as plant/soil interactions. The objectives of this study were to develop a synthetic method to create hydrophobic sand, and to determine if that hydrophobic sand would affect the establishment of bermudagrass (Cynodon dactylon L. Pers. × C. transvaalensis Burtt-Davy, cv. Tifeagle) sprigs. Two techniques were developed to render sand hydrophobic: soap:sand method (hydrophobic sand; HSS) and sand:peat method (hydrophobic sand and read sedge peat; HSP). Both HSS and HSP remained severely hydrophobic at 0 cm depth for only 7 d, and at the 1- to 6-cm depth for 77 continuous days, as determined by water drop penetration time. Bermudagrass establishment, root growth, or shoot growth in two greenhouse experiments with four root zone substrates–HSS, HSP, WSAND (wettable sand), and WSP (wettable sand and reed sedge peat)—were not consistent. In conclusion, both HSS and HSP were shown to be safe and effective methods to synthetically produce hydrophobic sand for potential use in laboratory research, but further evaluation is needed to determine the feasibility of using HSS and HSP for turfgrass growth evaluations.

76 Digestibility of a diet with or without reed sedge peat in exercised horses

An experiment was conducted to determine the effect of a concentrate diet containing Reed Sedge Peat (RSP) on nutrient digestibility, and serum glucose and insulin concentrations in mature exercised horses. The addition of RSP to the diet may effect nutrient digestibility and glucose metabolism in exercising horses. Six stock-type geldings (μ 546 kg), ranging from 8 to 19 yr of age, were fed a diet consisting of coastal Bermudagrass hay and a concentrate with or without RSP in a duplicated 3 × 3 Latin-square design. Three dietary treatments consisted of: control, no RSP (C); 10 lb/ton RSP (RSP10; Kent Nutrition Group, Muscatine, IA); and 20 lb/ton RSP added (RSP20). The 12-wk study consisted of 3 21-d adjustment periods followed by a 3-d fecal collection period. Total feces voided was collected every 4 h. Blood was collected 30 min pre-feeding, 30 min post-feeding, 8 h post-feeding, 30 min pre- Standard Exercise Test (SET); then 30 s, and 10, 30, 60, and 120 min post-SET. Horses were fed hay at a minimum 2% body weight per day and 2.2 kg/d of each dietary treatment. Feed and feces were analyzed for dry matter (DM), crude protein (CP), ether extract (EE), acid detergent fiber (ADF), neutral detergent fiber (NDF), ash, Ca, and P concentrations. Blood serum was analyzed for fasting insulin and glucose concentrations. Data for nutrient digestibilities, and serum glucose and insulin concentrations were analyzed using theProc Mixed Procedure of SAS v. 9.4. Significant differences between means were declared at P < 0.05. There was an effect of period on apparent DM (P = 0.02), NDF (P = 0.04), ADF (P = 0.01), Ca (P = 0.03), and P (P = 0.01) digestibility. There was an effect of treatment (P = 0.03) on pre- and post-prandial serum glucose concentrations. Horses consuming RSP20 (95.5 mg/dL) had greater overall mean serum glucose concentrations compared with horses consuming RSP10 (87.2 mg/dL) and C (86.6 mg/dL). Overall post-prandial serum insulin concentrations (17.81 uIU/mL) were greater (P < 0.01) compared with pre-prandial (7.1 uIU/mL) and 8 h post-prandial (6.52 uIU/mL). Immediately following exercise, mean serum glucose concentrations decreased (P < 0.01) from 86.43 mg/mL pre-SET to 80.13 mg/dL. Serum insulin concentrations decreased (P < 0.01) from 5.56 ulU/mL pre-SET to 3.05 ulU/mL post-SET. The data suggests no benefits were observed in nutrient digestibility when RSP was added to horses’ diets. However, greater glucose concentrations with the RSP20 diet may provide more energy for performance of the horse. Therefore, further research may be warranted to investigate effects of RSP on glucose and insulin dynamics in exercising horses.

Quantitative Description and Classification of Growing Media Particle Morphology through Dynamic Image Analysis

The physical properties of growing media are dependent on the morphological characteristics of the particles composing them. Thus, their characteristics can be more precisely altered for specific purposes by a better morphological design of materials to optimize the use of raw materials and increase water efficiency. There are many references on the relationship between basic particle size and physical properties, but the arrangement of the particles and the resulting physical properties are also affected by the shape of the particles. Growing media have seldom been characterized by shape criteria and, therefore, their influence remains unknown. A dynamic image analyzer, the QicPic device, was used to assess particle shape and size for a wide diversity of growing media constituents. As well as FeretMAX and ChordMIN diameters describing individual particle length and width, respectively, individual particle shape was analyzed in terms of several descriptors (aspect ratio, circularity, roundness, and convexity). A classification was established to discern different particle shapes and all materials were described accordingly. Correlations between particle morphology descriptors were reported, showing that the greater the particle length, the smaller the width/length ratio, circularity, roundness, and convexity. Circularity, roundness, particle length, and its associated relative span were identified as the most relevant parameters describing materials’ morphology. This work shows a large diversity in particle morphology of growing media constituents, which were categorized into four classes of materials. Three classes were mainly described according to their particle shapes, with a decreasing elongation and an increasing circularity, roundness, and convexity: (1) fine and coarse wood and coir fibers; (2) all Sphagnum white peats, milled or sod; and (3) black peats, sedge peat, coir pith, fresh and composted pine bark, green waste compost, and perlite. A fourth class was represented by coir medium (mixing pith and fibers) and was above all characterized by high diversity in particle length. These findings extend the characterization of the materials for a more thorough evaluation of the links between particle morphology and physical properties.

Lake Tagimaucia Montane Lake as a Potential Late Holocene Environmental Archive in Fiji's Volcanic Highlands

Lake Tagimaucia, a montane volcanic lake on Taveuni Island, is Fiji's only high-elevation lake. This study examined a lacustrine sediment core to explore the lake's potential as a palaeoenvironmental archive through the Late Holocene. Dating reveals no simple age–depth relationship due to sediment age-reversals. However, phases of fire activity are evidenced by two distinct charcoal bands. Catchment burns were probably related to significant ENSO-driven drought, although fire ignition by volcanic eruptions on Taveuni cannot be ruled out. Above the dominant charcoal band, the sediment profile exhibits notable positive shifts in organic matter, bulk density, δ13C, and C:N ratio. These peaks suggest a phase of accelerated catchment erosion, possibly triggered by post-burn instability. We introduce a conceptual model to explain the influence of sedge peat swamps on lake sedimentation processes. Surrounding sedge-dominated peatlands have extensively encroached Lake Tagimaucia. Floating peat mats, gradually accumulating through time, act as a repository of organic material that is stored directly on the lake surface. Episodes of drought and fire release old organics directly into the lake itself, probably contributing to the complex chronological sequence in the Late Holocene stratigraphy.

Anti-Allergic Properties of Humic Acids Isolated from Pine-Sphagnum-Cotton Sedge Peat.

The course administration of humic acids isolated by the sodium pyrophosphate method from pine-sphagnum-cotton sedge peat reduced the general anaphylaxis reaction in mice and guinea pigs immunized with ovalbumin and decreased serum content of IgG1 and IgE in mice. The serum from mice treated with humic acids and sensitized with ovalbumin did not increase the rate of degranulation of mast cells isolated from intact Wistar rats in the presence of ovalbumin in comparison with the serum of control animals.

Landless Urban Rooftop Farming Context of Soilless Culture for Microbe Frees Cultivation, Roof Security and Environmental Sustainability

Landless rooftop farming is an artificial cultivation on the roof which uses organic solid or liquid media called solution culture “media culture” or water culture “hydroponics”. Media culture and hydroponics has been used sporadically throughout the world in rooftop and tissue culture also has been used the world as commercial means of growing both food and ornamental plants. It supplies fresh vegetables in countries with limited arable land as well as in small countries with large populations. Plants grown by hydroponics have concisely superior quality, high yield, rapid harvest, and high content, at present it is used widely in research facilities as a technique for studying plant nutrition. Gravel or sand is sometimes used in soilless systems to provide plant support, and retain some nutrients and water. The retention and water can be for their improvement through the used materials, but others such as rice hulls, bagasse, sedge peat, and sawdust are used sometime as constituents in soilless mixture straw bales have been used as the growing medium in England and Canada. Rockwool (porous stone fiber) is used in Europe. Since the major constituent of the media in artificial growing systems may be solid or liquid, it is appropriate to use the term soil culture in reference to this general type of growing system and reserve the term hydroponics for those in which water is the principal constituent. Soilless organic media preparation and use has a tremendous effect in land less culture. It is basically used in Rooftop vegetable cultivation.

Thickness of peat influences the leaching of substances and greenhouse gas emissions from a cultivated organic soil

The off-site effects of agricultural organic soils include the leaching of N, P, and organic carbon (OC) to watercourses and CO2, CH4, and N2O emissions into the atmosphere. The aim of this study was to quantify how the thickness of organic layers affects these loads. A 19.56-ha experimental field drained by subsurface pipes was established in Ruukki, northwestern Finland. Three plots had a 60–80 cm-thick sedge peat layer and three others had a thickness of 20 cm or less. The drainage pipes lie in mineral soil that, in this field, contains sulfidic material. This study documents the experimental settings and reports on the leaching of substances in the first two years, as well as CO2, CH4 and N2O emissions during eight weeks in one summer. Total N (TN) and OC loads were higher from the thicker peat plots. The mean TN loads during a hydrological year were 15.4 and 9.2 kg ha−1 from the thicker and thinner peat plots, respectively, with organic N representing 36% of TN load. Total P (TP) load averaged 0.27 kg ha−1 yr−1. Dissolved P load represented 63 and 36% of TP in the thicker peat area and only 23 and 13% in the thinner peat area, and was thus increased upon peat thickness. These N and P loads through the subsurface drainage system represented roughly 83% of TN and 64% of TP loads from this field. There were no clear differences in greenhouse gas emissions among the plots during the eight-week monitoring period. Slowly oxidizing sulfide in the subsoil resulted in annual leaching of 147 kg S ha−1, almost ten times that of non-sulfidic soils. Our first results emphasize the effect of the peat thickness on the leaching of substances and warn about considering all organic soils as a single group in environmental assessments.

Distribution, morphometry, and ice content of ice‐wedge polygons in Tombstone Territorial Park, central Yukon, Canada

AbstractInvestigations of the regional distribution of ice‐wedge polygons and wedge‐ice volume allow for the assessment of the vulnerability of permafrost landscapes to thaw‐induced disturbances and related ecological feedbacks. Ice‐wedge polygons have been described in multiple studies in flat terrain and low‐gradient hillslopes, but few studies have examined ice‐wedge polygons in mountainous terrain. This study investigates the distribution, morphometry, and wedge‐ice content of ice‐wedge polygons in Tombstone Territorial Park, a mountainous permafrost region in central Yukon. Results show that ice‐wedge polygons occupy 2.6% of the park and preferentially develop in woody sedge peat, glaciofluvial, and alluvial deposits along the lower reaches of the Blackstone and East Blackstone rivers on hillslopes ≤1°. The morphometry of five of six polygonal sites studied showed statistically similar polygon sizes and trough angles, while showing different development stages based on vegetation type, surface wetness, and spatial pattern. The estimation of wedge‐ice volumes in the ice‐wedge polygons is 8–22% and is comparable to that of other Arctic regions. However, the estimated wedge‐ice volume represents a minimum value because older generations of ice wedges are truncated 3–4 m below the surface with no evidence of surface polygons, and the polygonal network can be obscured by slope processes, vegetation, and ice‐wedge inactivity. This study provides insights into the application of morphometric and soil parameters for the assessment of ice‐wedge polygon distribution and development stages.

Analysis of peat soil organic carbon, total nitrogen, soil water content and basal respiration: Is there a ‘best’ drying temperature?

Soil needs to be dried in order to determine water content, soil organic carbon content (SOC) and total nitrogen content (N). Water content is commonly measured using standard methods that involve drying temperatures of 105–110 °C. Recommended drying temperatures differ for the determination of SOC and N. However, at moderate drying temperatures, microbial activity might lead to organic matter mineralisation and nitrification, and thus to an underestimation of SOC and N. Furthermore, low drying temperatures might not dewater soils sufficiently to correctly determine water content or bulk density. Chemical processes such as thermal decomposition and volatilisation might occur at higher temperatures. This raises the question of whether the same sample can be used to determine water content, SOC and N. Further, the effect of drying, especially at different temperatures, on basal respiration of peat soils determined by incubation experiments is so far unknown. Effects of drying temperature might be especially severe for peat soils, which have high SOC and water contents.This study systematically evaluated the effect of different drying temperatures (20, 40, 60, 80 and 105 °C) on the determination of mass loss (proxy for water content), SOC and N over a wide range of 15 different peat soils comprising amorphous, Sphagnum and sedge peat substrate. The investigated peat soils had SOC contents ranging from approximately 16.8–52.5% with different degrees of decomposition. They were thus separated into two ‘peat groups’ (amorphous and weakly decomposed). In a subsequent investigation, an incubation experiment was carried out on a subset of five peat soils to investigate the pre-treatment effect of different drying temperatures on basal respiration. The results showed that amorphous samples should be dried at 105 °C to determine water content. The weakly decomposed peat soils in the study had reliable water contents for drying temperatures above 60 °C. For temperatures below 80 °C, the determined SOC and N were biased by residual water. This could be corrected for weakly decomposed samples, but for amorphous samples only for drying temperatures ≥60 °C. Thus, mineralisation of soil organic matter is likely to take place at lower drying temperatures which are not recommendable especially for amorphous peat prone to high mineralisation rates. This is supported by the results of the incubation experiment: The effect of peat type (amorphous topsoil vs. weakly decomposed subsoil) was greater than the effect of different drying temperatures, which nonetheless affected respiration rates. The differences between all five soils were consistent, irrespective of the drying temperature. Thus, incubation experiments might be possible using peat dried at moderate temperatures.

51 Digestibility of a diet with or without reed sedge peat in exercised horses

An experiment was conducted to determine the effect of a concentrate diet containing Reed Sedge Peat (RSP) on nutrient digestibility, and serum glucose and insulin concentrations in mature exercised horses. The addition of RSP to the diet in horses may be beneficial to increasing nutrient digestibility and performance factors of the horse. Six stock-type geldings, ranging from 8 to 19 yr of age, in a duplicated 3 × 3 Latin-square design were fed a diet consisting of Coastal Bermudagrass hay and a concentrate with or without RSP. Three diet treatments consisted of: control, no RSP added (C); 4.5 kg/ton RSP added (RSP10; Kent Nutrition Group, Muscatine, IA); and 9.0 kg/ton RSP added (RSP20). The 12-wk study consisted of 3 21-d adjustment periods followed by 3-d fecal collections. Blood collections were taken pre- and post-prandial, before, and immediately following a Standard Exercise Test (SET) on d 21 of each period. Horses were fed hay at 2% body weight per day and 2.2 kg/d of a concentrate diet with or without added RSP. Representative samples of feed and feces were analyzed for dry matter, crude protein (CP), crude fiber, ether extract, acid detergent fiber (ADF), neutral detergent fiber, and ash content. Serum was analyzed for glucose and insulin concentrations by Michigan State University Veterinary Diagnostic Endocrinology Department. Data for nutrient digestibilities, and serum glucose and insulin concentrations were analyzed using the Proc Mixed Procedure of SAS v. 9.4. Significant differences between means were declared at P

Digital, Three-Dimensional Visualization of Root Systems in Peat

Belowground plant structures are inherently difficult to observe in the field. Sedge peat that mainly consists of partly decayed roots and rhizomes offers a particularly challenging soil matrix to study (live) plant roots. To obtain information on belowground plant morphology, research commonly relies on rhizotrons, excavations, or computerized tomography scans (CT). However, all of these methods have certain limitations. For example, CT scans of peat cores cannot sharply distinguish between plant material and water, and rhizotrons do not provide a 3D structure of the root system. Here, we developed a low-cost approach for 3D visualization of the root system in peat monoliths. Two large diameter (20 cm) peat cores were extracted, frozen and two smaller peat monoliths (47 × 6.5 × 13 cm) were taken from each core. Slices of 0.5 mm or 1 mm were cut from one of the frozen monoliths, respectively, using a paper block cutter and the freshly cut surface of the monolith was photographed after each cut. A 3D model of the fresh (live) roots and rhizomes was reconstructed from the resulting images of the thinner slices based on computerized image analysis, including preprocessing, filtering, segmentation and 3D visualization using the open-source software Fiji, Drishti, and Ilastik. Digital volume measurements on the models produced similar data as manual washing out of roots from the adjacent peat monoliths. The constructed 3D models provide valuable insight into the three-dimensional structure of the root system in the peat matrix.

Roots, Tissues, Cells and Fragments—How to Characterize Peat from Drained and Rewetted Fens

We present analyses of macroscopic and microscopic remains as a tool to characterise sedge fen peats. We use it to describe peat composition and stages of peat decomposition, to assess the success of rewetting of a formerly drained fen, and to understand the workings of these novel ecosystems. We studied two percolation fen sites, one drained and one drained and rewetted 20 years ago. Years of deep drainage have resulted in a layer of strongly decomposed peat which lacks recognizable macro-remains. We could associate micro-remains with macro-remains, and thus still characterise the peat and the plants that once formed it. We show that the strongly decomposed peat is of the same origin as the slightly decomposed peat below, and that is was ploughed. We present descriptions of eight types of the main constituent of sedge peat: plant roots, including Carex rostrata type, C. lasiocarpa/rostrata type, C. limosa type, C. acutiformis type, C. echinata type, Phragmites australis type, Cladium type, Equisetum type. We describe three new non-pollen palynomorph types (microscopic remains) and five new subtypes. The rewetted fen provides insights into plant succession after rewetting and the formation of peat that predominantly consists of roots. Results indicate that leaf sheaths may be a consistent component of the peat.

Preliminary data on formation and depositional environments of lake Chaika in the central part of the Curonian Spit (Kaliningrad region, Russia, South-Eastern Baltic)

Lake Chaika is the only major water body present in the sand barriers of the entire territory of South-Eastern Baltic shoreline. The article provides new insights into the formation of Lake Chaika, based on data acquired through a lithological investigation of the lake sediment core combined with an organic matter content analysis, a macrofossil analysis, a radiocarbon AMS-dating and a bathymetric survey. The study revealed that Lake Chaika was formed around 500 years ago. The kettle of the lake appears to have not been submerged during the Littorina transgressions. During the mid-late Holocene, the kettle of the lake was occupied by the peat-forming ecosystems of alder carrs and sedge fens with scattered alder. The accumulation of ligneous and sedge peat occurred. The sand horizon, separating the gyttja layer from peat deposits, is considered to be a time marker for the so-called “sand disaster”, which began in the study site 200-250 years earlier than in the main territory of the Curonian Spit. There are three main formation phases of the lake’s ecosystem: the period of carrs (5390–510 cal. yr BP), the “sand disaster” period (≈550–500 cal. yr BP) and the proper lake period (500 cal. yr BP – present time).

Wat doet die bronzen pot daar bij de kei van Tijnje (Fr.)?

What is that bronze cauldron doing at the boulder of Tijnje (province of Friesland)? In 1937, a bronze cauldron was discovered at the occasion of the translocation of a huge boulder near the village of Tijnje. This boulder had been left behind after the retreat of the Pleistocene icecap. Starting in the Bronze Age, the landscape gradually became overgrown by peat, initially reed sedge peat and carr peat and later sphagnum peat. The boulder was probably never completely covered by peat. In the 11th and 12th centuries AD, land reclamation started in the area. Soon agriculture caused oxidation of the sphagnum peat, resulting in severe subsidence. Villages were abandoned. It was not until the 17th century that commercial companies started the exploitation of these now uninhabited peatlands by cutting turfs for fuel. It is argued that the cauldron was deposited at the foot of the boulder as a ritual offering on the occasion of the start of the exploitation of the area in the 17th century.

Holocene floodplain evolution in a central European loess landscape – geoarchaeological investigations of the lower Pleiße valley in NW Saxony

Abstract. Undisturbed sediments are an important source for the reconstruction of the Holocene development of valleys. Wide floodplains with relatively small rivers in a region settled since 5500 BCE offer opportunities for investigations regarding climatic and anthropogenic landscape change. In the context of a motorway construction, excavations were carried out by the Saxonian Heritage Office in the year 2015. At one of the sites it was possible to get a view of the sediments of the Pleiße valley less than 100 m distance from large cross sections described by Neumeister (1964) in a former open cast mine. Archaeological finds and features, plant remains and radiocarbon dating as well as micromorphological and geochemical investigations helped to decipher the age and the characteristics of the Holocene sediments: above Weichselian loamy sands a sedge peat developed in small depressions during the Preboreal and Boreal. The sands and the sedge peat are covered by a “black clay”, which was still the topsoil during the Atlantic period. The sedimentation of 2.3 m thick overbank fines began after 4000 BCE. A depth of 1 m below the surface a medieval Slavic find layer was excavated. These results show that sedimentation processes in the lower Pleiße valley significantly changed after 4000 BCE. It is obvious that the increase in silty material in the floodplain is caused by the land clearance in the Neolithic period. More than half of the silty overbank fines were deposited before the Middle Ages began.

CHARACTERISTICS OF HORNY ALTAI PEATS AND THEIR BIOLOGICAL ACTIVITY IN PLANT TISSUE CULTURE

The search for new raw materials of biologically active substances of natural origin is an urgent task for the modern period. Peat in this respect is a relatively cheap and almost unlimited raw material base. Peat of swamps can be used widely in agriculture for receipt of biologically active substances are of great interest in the territory of the Gorny Altai. The purpose of this work is to study the composition of organic matter of peats of the Gorny Altai, to choose peat raw materials for biologically active production and to study their biological activity. The object of the study was 46 swamps of the Gorny Altai. The following analyses were carried out in peats: botanical composition, degree of decomposition, ash content, group composition of peat organic matter. The composition of humic acids (ha) was analyzed by IR spectroscopy. For determine of the biological activity of humic acids was used plant tissue cultured . The results of the research allowed to distinguish peats by the content of HA: buckbean peat (47.0% of HA), wood peat (50.0% of HA), fern peat (55.0% of HA), grass peat (30.0–45.0% of HA), sedge peat (5.6–58.0% of HA), grass-buckbean peat (43.0–56.5% of HA) and to outline the raw material base for the production of BAS – peatland Turochak. According to the optimal characteristics of HAs, a sample was taken from a depth of 325-375 cm, HA was isolated. The biological activity In humic acid was determined with the use of plant tissue culture. High biological activity are proven of the preparations of HA from the peatland Turochak, which resulted in the acceleration of microclonal propagation of plants in vitro.

Interaction of natural organic matter with acid mine drainage: In-situ accumulation of elements

Natural organic matter (NOM) within the dispersion train of Novo-Ursk tailings (Salair Ridge, Kemerovo region, Russia) is composed of remnant sedge peat mounds and is located either on the surface or is buried under cyanide wastes. The organic material interacts with AMD and with the wastes, which leaves imprint on its composition. This interaction produces geochemical anomalies (g/t: 1582 Cu, 41,300 Zn, 6060 Se, 11,700 Hg, 114–155 Au, 534 Ag, 416 I). The contents of elements depend on Fe in three groups of NOM samples that contain <10 wt% Fe (group I), 10–22 wt% Fe (group II), and >22 wt% Fe (group III). NOM with higher Fe enrichment contains less Cu, Zn, Se, Hg, Ag and I, as well as Cd, Ba, Sr and Rb, Y, Zr, Nb, Mo, Sn, Sb, and Te but more As. Yet, gold may reach high concentrations in NOM with any Fe contents. Accumulation of elements by NOM during its prolonged interaction with wastes and AMD is maintained by physical, chemical, biochemical, and mineralogical processes. They are, respectively, migration of waters controlled by permeability of material in the dispersion train depending on its grain sizes and by AMD flow direction; oxidative dissolution of sulfides, complexing, and adsorption on organic matter and Fe(III) hydroxides; microbial mediation; and secondary mineralization. The chemistry of waters interacting with NOM at the time of its deposition can be reconstructed with regard to several factors, including microbial mediation. Namely, local geochemical anomalies with ultrahigh element concentrations may arise because microorganisms can immobilize Hg to make it less toxic; sulfate-reducing bacteria can maintain precipitation of Zn, Cu, and Cd sulfides; microbial activity can mediate redistribution of elements between clastic and organic materials, etc. The inferred inheritance of AMD geochemical signatures by NOM has implications for the conditions and mechanisms of element accumulation.

A submerged pine forest from the early Holocene in the Mecklenburg Lake District, northern Germany

For the first time, evidence of a submerged pine forest from the early Holocene can be documented in a central European lake. Subaquatic tree stumps were discovered in Lake Giesenschlagsee at a depth of between 2 and 5 m using scuba divers, side‐scan sonar and a remotely operated vehicle. Several erect stumps, anchored to the ground by roots, represent an in situ record of this former forest. Botanical determination revealed the stumps to be Scots pine (Pinus sylvestris) with an individual tree age of about 80 years. The trees could not be dated by means of dendrochronology, as they are older than the regional reference chronology for pine. Radiocarbon ages from the wood range from 10 880±210 to 10 370±130 cal. a BP, which is equivalent to the mid‐Preboreal to early Boreal biozones. The trees are rooted in sedge peat, which can be dated to this period as well, using pollen stratigraphical analysis. Tilting of the peat bed by 4 m indicates subsidence of the ground due to local dead ice melting, causing the trees to become submerged and preserved for millennia. Together with recently detected Lateglacial in situ tree occurrences in nearby lakes, the submerged pine forest at Giesenschlagsee represents a new and highly promising type of geo‐bio‐archive for the wider region. Comparable in situ pine remnants occur at some terrestrial (buried setting) and marine (submerged setting) sites in northern central Europe and beyond, but they partly differ in age. In general, the in situ pine finds document shifts of the zonal boreal forest ecosystem during the late Quaternary.

The impact of postglacial palaeoenvironmental changes on the properties of sediments in the kettle hole at the site of Jurki (NE Poland)

This research is focused on a small kettle hole located within the Morąg moraines (Ilawa Lake District, NE Poland). The study objective was to determine the impact of palaeoenvironmental changes in sedimentation and properties of sediments filling the bottom of the kettle hole. Sedimentological, geochemical, and palaeobotanical studies enabled us to distinguish several development phases of the kettle hole, and cluster analysis performed on physicochemical data yielded seven local geochemical zones (Ju I/I to Ju I/VII ). The beginning of biogenic sedimentation in the conditions of a small water body, functioning in the Late Glacial period (4.20–4.10 m), was determined on the basis of palaeobotanical research. Sediments deposited in the lake during its further evolution were rich in microelements such as Ca, Na, Mg, and K, and to a smaller extent – Fe and Mn (Ju I/I–III local geochemical zones). The Late Glacial lacustrine period ended with the accumulation of very silty, pollen-free gyttja, with a stratigraphic hiatus (Ju I/IV , 3.40–3.20 m). The sediments were enriched with SiO2ter, which indicates an increased rate of slope erosion, and concretions of Fe-Mn occurring below this layer (Ju III ) provide evidence for lowering of the water level and even desiccation. In the Holocene, the lacustrine period ended with the accumulation of coarse detrital gyttja (3.20–2.60 m). Palaeobotanical data indicate that the next group of sediments were deposited in the Late Subboreal and Subatlantic periods (2.60–0.0 cm, Ju I/V–VII ; sedge peat). Their properties were varied and related to hydrologic conditions, limited denudation, and vegetation succession. There was also a significant change in the trophic conditions of the water and consequently in the sediments of the kettle hole, which changed during the lacustrine period from basic to acid, and strongly acid in the surface layer. This reaction may be related to a change in the water regime as well as to human impact in the environment, which led to the colonization of the peat bog by Sphagnum moss.