Search Results (75)

Constructing heterojunctions can combine the superior performance of different two-dimensional (2D) materials and eliminate the drawbacks of a single material, and modulating heterojunctions can enhance the capability and extend the application field. Here, we investigate the physical properties of the heterojunctions formed by the contact of different atom planes of Janus MoSSe (JMoSSe) and graphene (Gr), and regulate the Schottky barrier of the Gr/JMoSSe heterojunction by the number of layers and the electric field. Due to the difference in atomic electronegativity and surface work function (WF), the Gr/JSMoSe heterojunction formed by the contact of S atoms with Gr exhibits an n-type Schottky barrier, whereas the Gr/JSeMoS heterojunction formed by the contact of the Se atoms with Gr reveals a p-type Schottky barrier. Increasing the number of layers of JMoSSe allows the Gr/JMoSSe heterojunction to achieve the transition from Schottky contact to Ohmic contact. Moreover, under the control of an external electric field, the Gr/JMoSSe heterojunction can realize the transition among n-type Schottky barrier, p-type Schottky barrier, and Ohmic contact. The physical mechanism of the layer number and electric field modulation effect is analyzed in detail by the change in the interface electron charge transfer. Our results will contribute to the design and application of nanoelectronics and optoelectronic devices based on Gr/JMoSSe heterojunctions in the future. Full article

Retention forestry creates anthropogenic ecotones that diversify forest landscapes in terms of age and biomass. Such diversification can have ambiguous ecological impacts, raising uncertainties, particularly for black alder swamp woodlands, which are considered sensitive and are prioritized in EU conservation policy. This study aimed to examine the effects of adjacent clear-cutting on ground cover vegetation in 12 black alder stands in the hemiboreal zone in Latvia 11 to 120 years since the harvest. Ground cover vegetation was recorded by species along 40 m transects. The effects of the time since adjacent stand harvesting and exposure to the edge on species richness and Shannon diversity were assessed using linear mixed-effects models. A detrended correspondence analysis was used to explore the main environmental gradients. A total of 103 species were recorded: 15 in the tree and shrub layer, 66 in the herbaceous layer, and 22 in the moss and lichen layer. The exposure to the adjacent stand had a moderate positive effect on species diversity, while the effects of edge age were complex and varied by stand type. The scale of disturbance (the absolute length of the analyzed edge), rather than edge age or exposure, had the most pronounced effect on ground cover vegetation composition, suggesting persistent secondary edge effects that should be considered in forest management and conservation planning. Full article

Hexavalent chromium (Cr(VI)), a highly toxic and carcinogenic contaminant, presents a significant hazard to aquatic ecosystems and human health. Developing environmentally friendly, cost-effective, biodegradable, and easily recyclable adsorbents is critical for efficient Cr(VI) removal. Here, we present an innovative solution using a Mg/Al layered double hydroxide (LDH)-modified sphagnum cellulose gel (MgAl/LDH@SMCG), prepared by pre-treating sphagnum cellulose, crosslinking with polyvinyl alcohol, and doping with LDH. The resulting porous composite gel features abundant -COOH and -OH chelating groups, significantly enhancing its adsorption capacity and structural stability. The material’s structure and surface modifications were systematically characterized using SEM, TGA, FT-IR, and XPS. Batch adsorption experiments were conducted to assess the influence of adsorbent dosage, initial Cr(VI) concentration, pH, contact time, and temperature on performance. Adsorption kinetics, isotherms, and thermodynamics analyses revealed a primary mechanism of monolayer chemical adsorption, with experimental data closely fitting the Freundlich isotherm and pseudo-second-order kinetic models. The modified gel exhibits increased surface roughness and adsorption sites, resulting in markedly improved Cr(VI) removal efficiency. This study not only provides theoretical insights into Cr(VI) adsorption but also highlights the potential of LDH-functionalized cellulose gels for heavy metal wastewater treatment, offering a sustainable pathway for addressing global water contamination challenges. Full article

Retention forestry is the dominant practice in Northern Europe, with large-scale clear-cuts following natural disturbances becoming more frequent as the climate changes. Despite its widespread use, clear-cutting is criticized for its potential adverse effects on species diversity and ecosystem recovery, particularly in understory vegetation. This study examines early vegetation changes after large-scale clear-cutting in Latvia’s hemiboreal forests. The sampling was conducted in 2017 and 2020, three and six years post-harvest, using 210 systematically placed plots (1 × 1 m) to assess species abundance and vegetation cover across moss/lichen, herbaceous, and shrub/tree layers. The findings indicate that species diversity was initially higher following clear-cutting but declined after six years, with the herbaceous layer most affected. While clear-cutting temporarily increases species diversity, negative effects become evident over time. Recovery is prolonged, with succession progressing faster in wet areas. To fully understand the long-term impacts of clear-cutting, continued monitoring is necessary. Full article

Bryophytes, including liverworts, mosses, and hornworts, play an irreplaceable role in soil moisture retention, erosion prevention, and pollution monitoring. The precise identification of bryophyte species enhances our understanding and utilization of their ecological functions. However, their complex morphology and structural symmetry make identification difficult. Although deep learning improves classification efficiency, challenges remain due to limited datasets and the inadequate adaptation of existing methods to multi-scale features, causing poor performance in fine-grained multi-classification. Thus, we propose MOSSNet, a lightweight neural network for bryophyte feature detection. It has a four-stage architecture that efficiently extracts multi-scale features using a modular design with symmetry consideration in feature representation. At the input stage, the Convolutional Patch Embedding (CPE) module captures representative features through a two-layer convolutional structure. In each subsequent stage, Dual-Branch Multi-scale (DBMS) modules are employed, with one branch utilizing convolutional operations and the other utilizing the Dilated Convolution Enhanced Attention (DCEA) module for multi-scale feature fusion. The DBMS module extracts fine-grained and coarse-grained features by a weighted fusion of the outputs from two branches. Evaluating MOSSNet on the self-constructed dataset BryophyteFine reveals a Top-1 accuracy of 99.02% in classifying 26 bryophyte species, 7.13% higher than the best existing model, while using only 1.58 M parameters, 0.07 G FLOPs. Full article

Dicranum is one of the most diverse and widespread genera within the family Dicranaceae, encompassing ca. 110 accepted species worldwide. However, the taxonomy of this genus remains notoriously complex, with the circumscription of several species still unresolved, thereby limiting our understanding of the Dicranum’s diversity. During a recent survey of Dicranum in China, we found an intriguing species characterized by a unique combination of morphological traits including stiff and fragile leaves, sharply denticulate leaf apices, elongated, rectangular and porose laminal cells throughout, bistratose or partially bistratose laminal cells in the distal part, 1–2 stratose alar cells, and a transverse section of the costa in the lower portion of leaf with two stereid bands and undifferentiated epidermal layers. Morphological and molecular phylogenetic analyses, based on five chloroplast markers and one nuclear marker, support the recognition of this moss as a new species, which we described here as Dicranum motuoense sp. nov. Furthermore, we present the complete organellar genomes of this newly identified species. The chloroplast genome of D. motuoense is 123.94 kb in length, while the mitochondrial genome is 105.77 kb in length. A total of 127 genes and 66 genes were identified in the chloroplast and mitochondrial genomes, respectively. This study not only advances our understanding of species diversity with Dicranum but also contributes to the broader knowledge of its evolution. Additionally, a key for the identification of Dicranum species with fragile leaves is included. Full article

Biological soil crusts (BSCs) play a fundamental role in desert ecosystems by stabilizing soil, cycling nutrients, and retaining moisture. However, the assembly processes governing bacterial communities within BSCs remain largely unknown. This study aimed to reveal the spatiotemporal variations in the bacterial community diversity, co-occurrence patterns, and ecological assembly processes of BSCs and their underlying soils across different desert and seasonal conditions. We systematically analyzed the spatial differences in the bacterial diversity, co-occurrence networks, and community assembly processes of BSCs and their underlying soils using samples collected at various soil depths from different BSC types in different deserts. We discovered that BSC type and soil depth were the primary factors driving bacterial community assembly, while seasonal effects were weaker and more indirect, and mainly regulated community dynamics through changes in resource availability and environmental conditions. The underlying soils of moss- and lichen-BSCs exhibited higher bacterial diversity and richness than those of algae BSCs. In contrast, cyano-BSCs exhibited a lower diversity, but Cyanobacteria demonstrated the highest photosynthetic function. Among the different deserts, the community assembly of samples from the eastern Inner Mongolia deserts was largely influenced by environmental selection, whereas stochastic processes were more prominent in the central and western desert regions. A β-nearest taxon index (βNTI) analysis indicated that stochastic processes were dominant in surface BSC samples, while environmental selection played a stronger role in deeper layers. A co-occurrence network analysis revealed that surface BSC samples had a high degree of network connectivity, with those from moss- and lichen-BSCs being particularly high, and they also exhibited high modularity and local clustering that promoted the functional stability of the microbial communities. This study revealed the integrated effects of soil depth, BSC type, desert type, and resource availability on microbial community assembly in desert ecosystems. These findings provide a theoretical basis for the microbial management of BSCs and scientific insights to support restoration strategies in desert ecosystems. Full article

This study investigated the impact of forest fertilization on ground vegetation in deciduous and conifer stands across different forest site types (forests with drained mineral soils, forests with drained organic soils, and dry upland forests), stand age groups (young, middle-aged, and pre-mature), and fertilizer types (ammonium nitrate (NH₄NO₃) and wood ash alone, and both together). Ground vegetation was surveyed one to three years after fertilizer application, with the projected ground cover of individual species in the moss and herb layers determined. Thus, results reflect short-term impact of fertilization. Species richness and diversity (Shannon diversity index, H′) were compared between fertilized and control (unfertilized) plots. The results show that species diversity in the moss layer of silver birch stands was significantly affected by fertilization, while species richness was significantly influenced by the interaction between fertilization and forest site type. Differences between control and fertilized plots in birch stands suggest a potentially negative response of the moss layer to fertilization. In contrast, no significant effect of fertilization was observed in Norway spruce stands, where site type and stand age emerged as significant factors. In Scots pine stands, where NH₄NO₃ was applied alone, fertilization had a significant impact on both species richness and diversity in the herb layer. In the moss layer, a marginally significant effect was found for the interaction between fertilization and stand age. NH₄NO₃ alone appeared to enhance herb layer richness, although its effect on species diversity was more variable. Our study highlights the context-dependent nature of fertilization effects on species richness and diversity in Latvian hemiboreal forest ecosystems. Full article

The development of state-of-the-art gas sensors based on metal oxide semiconductors (MOS) to monitor hazardous and greenhouse gas (e.g., methane, CH₄, and carbon dioxide, CO₂) has been significantly advanced. Moreover, the morphological and topographical structures of MOSs have significantly influenced the gas sensors by means of surface catalytic activities. This work examines the impact of morphological and topological networked assembly of zinc oxide (ZnO) nanostructures, including microparticles and nanoparticles (0D), nanowires and nanorods (1D), nanodisks (2D), and hierarchical networks of tetrapods (3D). Gas sensors consisting of vertically aligned ZnO nanorods (ZnO–NR) and topologically interconnected tetrapods (T–ZnO) of varying diameter and arm thickness synthesized using aqueous phase deposition and flame transport method on interdigitated Pt electrodes are evaluated for methane detection. Smaller-diameter nanorods and tetrapod arms (nanowire-like), having higher surface-to-volume ratios with reasonable porosity, exhibit improved sensing behavior. Interestingly, when the nanorods’ diameter and interconnected tetrapod arm thickness were comparable to the width of the depletion layer, a significant increase in sensitivity (from 2 to 30) and reduction in response/recovery time (from 58 s to 5.9 s) resulted, ascribed to rapid desorption of analyte species. Additionally, nanoparticles surface-catalyzed with Pd (~50 nm) accelerated gas sensing and lowered operating temperature (from 200 °C to 50 °C) when combined with UV photoactivation. We modeled the experimental findings using a modified general formula for ZnO methane sensors derived from the catalytic chemical reaction between methane molecules and oxygen ions and considered the structural surface-to-volume ratios (S/V) and electronic depletion region width (L_d) applicable to other gas sensors (e.g., SnO₂, TiO₂, MoO₃, and WO₃). Finally, the effects of UV light excitation reducing detection temperature help to break through the bottleneck of ZnO-based materials as energy-saving chemiresistors and promote applications relevant to environmental and industrial harmful gas detection. Full article

Biological soil crusts are complex biological soil layers formed by mosses, lichens, cyanobacteria, and the underlying soil, which together with plants affect rainfall infiltration, surface runoff, soil evaporation, and water movement in the soil. The soil desertification and soil erosion in the ecologically fragile areas of central Ningxia are serious problems, and the ecological environment is extremely fragile. Effective ecological restoration technologies are urgently needed. This study took the grassland in the ecologically fragile area of central Ningxia as the object and investigated the impact of three plant communities and symbiotic patterns of biological soil crusts on soil erosion through field simulated rainfall experiments. The results showed that: (1) At a rainfall intensity of 90 mm h⁻¹, the initial runoff time of each slope was significantly positively correlated with plant community type and biological soil crust coverage, and prolonged with the increase of plant community type and biological soil crust coverage. (2) With the extension of rainfall duration, the cumulative runoff on each slope exhibited an increasing trend. (3) The sediment concentration in runoff on slopes under different plant community and biological soil crust symbiotic patterns was significantly different, with the sediment concentration decreasing as the type of plant community and the coverage of biological soil crusts increased. (4) With the increase in the diversity of plant communities and the coverage of biological crusts, there was a gradual reduction in the volume of accumulated sediment. This study offers scientific management strategies and practical guidance for soil and water conservation efforts in the ecologically vulnerable areas of central Ningxia, highlighting the importance of promoting these symbiotic models within the region. Full article

This study examines a boreal peatland (the Sagnes peatland, Fanay, Limousin, France) with a depth of 1 m. This peatland is currently in the late stages of organic deposition, as evidenced by the growth of Carex species, along with Sphagnum mosses, in the uppermost level. To gain molecular insights, we conducted an analysis of the lignin and polyphenolic counterparts using HMDS (hexamethyldisilazane) thermochemolysis, enabling the identification of lignin degradation proxies. The goal was to develop characteristic indicators for the state of lignin degradation based on the relative distribution of lignin phenols, measured by gas chromatography coupled with mass spectrometry (GC-MS) after the HMDS thermochemolysis. For that purpose, the singular contribution of the 11 aromatic moieties yielded, along with SGC (sum of lignin moieties) and the most lignin degradation proxies, were applied. It has been shown that HMDS thermochemolysis exhibited the capacity to reveal oxidized and degraded lignin fractions, following the increasing trend yielded for most moieties and SGC proxy, in the mesotelm and catotelm layers. In addition, the C/G (Cinnamyl/Guaiacyl) and S/G (Syringyl/Guaiacyl) ratios showed their highest input in the upper half of the core. This bias in the aforementioned ratios could indicate that HMDS thermochemolysis is to be applied for geological samples, where low G-compounds exist. For the sake of validating HMDS thermochemolysis’ application, Principal Component Analysis (PCA) was then applied to the molecular fingerprint. For ratios and proxies of aromatic moieties of HMDS thermochemolysis, the PCA approach exhibited a higher contribution (79%). This indicates the efficiency of these ratios in describing the molecular fingerprint of peat depth records. In addition, a higher separation between the contributions of the investigated variables (molecular proxies) along the first two PCs was noticed. In other words, the variables that showed a high contribution towards PC₁ exhibited a low contribution towards PC₂, and vice versa. These findings indicate the high reliance of applying the ratios and proxies of HMDS thermochemolysis. Full article

Between 2023 and 2024, a type of green alga was observed for the first time settling on Oil-tea Camellia leaves and branches in the eastern Oil-tea Camellia planting area of Hainan Island, forming a layer of gray-green moss with a rough surface that seriously interfered with the leaves’ normal photosynthesis. To further research the issue, this study used the plant photosynthesis measurement system and the paraffin sectioning technique to compare and analyze the changes in photosynthetic characteristics and anatomical structure of healthy and green algal-covered Oil-tea Camellia leaves. At the same time, the algal strain was effectively separated and purified using the plate delineation method, and its species classification was determined by combining morphological observation and molecular identification based on SSU-ITS sequences. The results of the study demonstrated that the coating of green alga facilitated the lignification of the leaf’s epidermal cell walls. After being covered by the green alga, the intercellular CO₂ concentration (Ci) increased significantly by 21.5%, while the net photosynthetic rate (Pn), transpiration rate (Tr), and stomatal conductance (Gs) all significantly decreased by 72.8%, 30.4%, and 24.9%, respectively. More specifically, the green alga that covers the leaves of Oil-tea Camellia was identified as Desmodesmus armatus of Chlorophyta. Notably, the green alga had a long growth cycle, did not undergo a decline phase within one month, had an optimal growth pH of 11.0, and could flourish in excessively alkaline conditions. In conclusion, this study not only reported for the first time the phenomena of D. armatus infesting Oil-tea Camellia leave, but also showed its unique physiological and ecological properties, providing a foundation for future research on relevant prevention and control approaches. Full article

Begonia rex cv. DS-EYWA is an important plant for indoor and outdoor cultivation, and cv. DS-EYWA is a rare unique cultivar with curly, colorful leaves. Due to their importance, applying plant tissue culture techniques for mass and healthy production in a short period of time without seasonal limitation is of immense economic value. Applying several concentrations of silver nitrate (AgNO₃) in combination with varied concentrations of cytokinins including 6-benzylaminopurine (BAP), thidiazuron (TDZ) (0, 0.5, 1, 1.5 mgL⁻¹), and 1-naphthaleneacetic acid (NAA) auxin (0, 0.5, 1 mgL⁻¹) via focusing on transverse thin cell layer (tTCL) petiole explants for high-scale production was used to establish an efficient in vitro propagation protocol. Our results showed that even low concentrations (25 mgL⁻¹) can control internal bacterial infection and increase shoot direct regeneration efficiency. A combination of 1.5 mgL⁻¹ BAP, 0.5 mgL⁻¹ NAA, and 25 mgL⁻¹ AgNO₃ was the best treatment to increase the number of direct regenerated shoots, and a lower concentration of BAP (0.5 mgL⁻¹) can be suggested for shoot elongation. Elongated shoots were successfully rooted in MS basal medium and acclimatized in a 1:1 peat moss/perlite sterilized pot mixture. Full article

The distribution of Scots pine (Pinus sylvestris L.) forests, particularly the Vaccinio myrtillo-Pinetum type, is determined by edaphic conditions, and although clear-cutting is used to promote regeneration, it remains controversial. This study evaluated the changes in non-living (forest floor and dead wood) and living (mosses, herbs, and dwarf shrubs) ground cover in clear-cut areas and reforested Scots pine stands. Continuous ground cover studies were conducted in clear-cuts, with samples collected over three years after clear-cutting, while data from 8–80-year-old and mature Scots pine stands were collected using the chronological series method with a consistent methodology in temporary plots. The research has shown that, as ecosystem recovery progresses, similarity to the mature forest increases, and a threshold stand age has been identified, beyond which the ecological changes induced by clear-cutting diminish. The study findings demonstrated that clear-cutting in Pinetum vaccinio-myrtillosum-type forest stands lead to a rapid increase in herb and dwarf shrub cover due to reduced competition for light and nutrients. However, clear-cutting caused a significant decline in forest-specific species and a drastic reduction in forest floor and dead wood mass, with a gradual recovery of moss cover over 10–30 years. These findings highlight the importance of managing clear-cutting practices to balance immediate vegetative responses with long-term ecosystem stability and biodiversity conservation. Full article

Extensive green roofs provide for many ecosystem services in urban environments. The efficacy of these services is influenced by the vegetation structure. Despite their key role in plant performance and productivity, but also their contribution to nitrogen fixation or carbon sequestration, green roof microbial communities have received little attention so far. No study included a spatiotemporal aspect to investigate the core microbiota residing in the substrates of extensive green roofs, although these key taxa are hypothesized to be amongst the most ecologically important taxa. Here, we identified the core microbiota residing in extensive green roof substrates and investigated whether microbial community composition is affected by the vegetation that is planted on extensive green roofs. Eleven green roofs from three different cities in Flanders (Belgium), planted either with a mixture of grasses, wildflowers and succulents (Sedum spp.; Sedum–herbs–grasses roofs) or solely species of Sedum (Sedum–moss roofs), were seasonally sampled to investigate prokaryotic and fungal communities via metabarcoding. Identifying the key microbial taxa revealed that most taxa are dominant phylotypes in soils worldwide. Many bacterial core taxa are capable of nitrogen fixation, and most fungal key taxa are stress-tolerant saprotrophs, endophytes, or both. Considering that soil microbes adapted to the local edaphic conditions have been found to improve plant fitness, further investigation of the core microbiome is warranted to determine the extent to which these stress-tolerant microbes are beneficial for the vegetational layer. Although Sedum–herbs–grasses roofs contained more plant species than Sedum–moss roofs, we observed no discriminant microbial communities between both roof types, likely due to sharing the same substrate textures and the vegetational layers that became more similar throughout time. Future studies are recommended to comprehensively characterize the vegetational layer and composition to examine the primary drivers of microbial community assembly processes. Full article