Extreme Environmental Conditions Research Articles

Stamens enclosed by petals in Berchemia (Rhamnaceae): a unique mechanism for pollen presentation

IntroductionPollen is usually presented by the anthers after maturity. However, in some plants, pollen is presented to pollinators on other floral structures (other than the anthers), or via particular expulsion mechanisms, resulting in secondary pollen presentation. The unusual petal morphology in Berchemia mediates pollen presentation, characterised by a combination of secondary pollen presentation and primary pollen presentation. However, the function, the role in reproduction, and the evolutionary significance of the unusual petals remain unclear.MethodsIn this study, we took Berchemia flavescens and Berchemia polyphylla var. leioclada as examples, and used field observations, semi-thin sections technology, scanning electron microscopy, and pollination ecology detection methods to explore the unique pollen presentation strategies, petal functions, and reproductive strategies in Berchemia.ResultsThis is a unique pollen presentation process mediated by petals. In the advanced bud stage, petals curl inward, enclosing the stamens. Following anther dehiscence, pollen is released into the petal tube, where the filament and cone-shaped anthers act as pistons, extruding pollen or pollen clumps through gaps at the petal tube apex (secondary pollen presentation). Subsequently, as the anthers emerge from the petal tube, residual pollen is directly presented to pollinators (primary pollen presentation).DiscussionIn Berchemia, the petals enclosing the stamens, effectively shield the pollen from extreme environmental conditions. The petal-stamen complex slow movement (first centrifugal, later centripetal) and pollen presentation in Berchemia suggest a unique reproductive strategy. This mechanism promotes outcrossing, minimizing interference between the pistil and stamens, and offers reproductive assurance by delayed self-pollination.

Tolerance to NSAIDs in Actinobacteria From a Mexican Volcano Crater: Genomics and Bioremediation Potential.

Non-steroidal anti-inflammatory drugs (NSAIDs) are emerging contaminants that pose significant health and environmental risks due to their persistence, including their presence in drinking water. Bioremediation, particularly through microorganisms such as actinobacteria, offers a sustainable approach to mitigate these pollutants. Actinobacteria from poly-extreme environments exhibit unique genetic and metabolic adaptations, enabling resistance to and degradation of various contaminants. This study aimed to evaluate the tolerance of actinobacteria to NSAIDs and conduct a genomic analysis of a selected strain. Actinobacteria were isolated from the crater of the Chichonal volcano [Chiapas, Mexico), resulting in 16 isolates. Among these, Micrococcus luteus P8SUE1, Micrococcus yunnanensis P9AGU1, and Kocuria rhizophila P1AGU3 demonstrated tolerance to diclofenac, ibuprofen, and paracetamol at concentrations of 1 ppm, 10 ppm, and 100 ppm, respectively. Whole-genome sequencing of M. yunnanensis P9AGU1 identified genes linked to the degradation of aromatic compounds and adaptations to extreme environmental conditions, highlighting its potential for bioremediation applications.

Unveiling climate extremes: A bibliometric odyssey through resilience, adaptation, and sustainable development goal synergies

Abstract In order to achieve sustainable development, it is critical to comprehend the intersectionality of severe events and the tactics used for their mitigation and adaptation as the effects of climate change become more widespread. This study explores the complex relationship between environmental challenges, climate change, and the Sustainable Development Goals (SDGs). It highlights the significant threat posed by environmental degradation, driven by both natural and anthropogenic factors, and its impact on global climate patterns. The study emphasizes the role of greenhouse gases in altering climate systems and the disproportionate effects on developing countries. It underscores the importance of sustainable development, as outlined in the 2030 Agenda for Sustainable Development, and the need for urgent action to combat climate change (SDG 13). The paper explores various theoretical perspectives on development, including the modernization theory and dependency theory, and their implications for environmental sustainability. It discusses the environmental Kuznets curve (EKC) hypothesis, which suggests a relationship between economic growth and environmental degradation, and presents contrasting views from contemporary research. The study also examines the socio-economic impacts of extreme environmental conditions and the importance of disaster risk reduction frameworks like the Sendai Framework. It highlights the ongoing challenges of climate change, such as increased greenhouse gas emissions and their effects on human health, agriculture, and water resources. Furthermore, the paper delves into the concept of sustainability and sustainable development, emphasizing the need for a balanced approach that integrates economic growth, environmental protection, and social equity. It reviews the historical evolution of sustainable development goals and the critical role of international cooperation in achieving these objectives. The findings of this paper provide valuable insights for policy makers, researchers, and practitioners working towards a more sustainable and resilient future. By addressing the complex interplay between climate change and sustainable development, the study aims to contribute to the global discourse on environmental sustainability and the achievement of the SDGs by 2030.

Numerical Analysis and Modeling of a Semi-Submersible Floating Wind Turbine Platform with Large Amplitude Motions Subjected to Extreme Wind and Wave Loads

The objective of this study is to predict the large amplitude motions of floating wind turbine platforms and to emphasize the significance of nonlinear forces when these platforms are subjected to combined wind and wave loads. The analysis utilizes the 5 MW OC4 semi-submersible model. First, we couple the OpenFAST v3.1.0 with SIMDYN, validate the effectiveness of the coupled program, and highlight the considerable impact of nonlinearity on the results, particularly in relation to the heave and pitch motions of offshore wind platforms under extreme environmental conditions. We then discuss the primary reasons for this phenomenon. Ultimately, this study proposes an optimized model aimed at mitigating the nonlinear effects associated with such conditions.

Evaluating Pipeline Inspection Technologies for Enhanced Corrosion Detection in Mining Water Transport Systems

Water transport pipelines in the mining industry face significant corrosion challenges due to extreme environmental conditions, such as arid climates, temperature fluctuations, and abrasive soils. This study evaluates the effectiveness of three advanced inspection technologies—Guided Wave Ultrasonic Testing (GWUT), Metal Magnetic Memory (MMM), and In-Line Inspection (ILI)—in maintaining pipeline integrity under such conditions. A structured methodology combining diagnostic assessment, technology research, and comparative evaluation was applied, using key performance indicators like detection capability, operational impact, and feasibility. The results show that GWUT effectively identifies surface anomalies and wall thinning over long pipeline sections but faces depth and diameter limitations. MMM excels at detecting early-stage stress and corrosion in inaccessible locations, benefiting from minimal preparation and strong market availability. ILI provides comprehensive internal and external assessments but requires piggable pipelines and operational adjustments, limiting its use in certain systems. A case study of critical aqueducts of mining site water supply illustrates real-world technology selection challenges. The findings underscore the importance of an integrated inspection approach, leveraging the complementary strengths of these technologies to ensure reliable pipeline integrity management. Future research should focus on quantitative performance metrics and cost-effectiveness analyses to optimize inspection strategies for mining infrastructure.

Hydrogen-Bonded Organic Framework Films Integrated with Wavy Structured Design for Wearable Bioelectronics.

The integration of hydrogen-bonded organic frameworks (HOFs) with flexible electronic technologies offers a promising strategy for monitoring detailed health information, owing to their inherent porosity, excellent biocompatibility, and tunable catalytic capabilities. However, their application in wearable and real-time health monitoring remains largely unexplored, primarily due to the mechanical mismatch between the traditionally fragile HOFs particles and the softness of human skin. Herein, this study demonstrates an epidermal biosensor that maintains reliable sensing capability even under extreme deformation and complex environmental conditions by integrating HOFs films with wavy bioelectrodes. This wearable biosensor demonstrates ultrasensitive detection capabilities, with a limit of detection of 49.64nM, and accurately measures nutritional content in sweat while conforming to curved skin surfaces. The sensor's performance is comparable to those obtained using high-performance liquid chromatography (HPLC). More strikingly, scratched HOFs films can be regenerated through a simple solvent rinsing process, enabling their reuse in the fabrication of new biosensors and offering a significant advantage over conventional sensing materials. This work has the potential to inspire the development of more flexible electronic devices, leveraging the structural adaptability and diversity of HOFs for personalized healthcare applications and real-time health monitoring.

Model predictive control for risk-based inspection and maintenance planning of offshore wind turbines

ABSTRACT Offshore wind turbines (OWTs) are highly susceptible to fatigue deterioration under extreme environmental conditions, making optimal inspection and maintenance (I&M) planning critical for their safe and sustainable operation. The dynamic nature of weather and complex deterioration processes challenge the long-term effectiveness of maintenance strategies. Moreover, I&M policies often become outdated when deterioration models are updated. Unlike traditional approaches that rely on a fixed life-span horizon, effective I&M planning must adapt to evolving conditions and varying planning horizons. This paper introduces a model predictive control (MPC) method for adaptive, risk-based I&M planning of OWTs. The closed-loop MPC approach provides flexibility by dynamically adjusting inspection and maintenance strategies based on evolving fatigue risks. We propose an augmented state-space model that captures the impact of probabilistic I&M actions on fatigue failure risks over time. A finite-horizon optimal control problem is then formulated to derive the MPC controller, which balances fatigue risk and I&M costs over the planning horizon. The proposed method is demonstrated using a fatigue-prone OWT component. Results show that the MPC controller effectively manages the trade-off between fatigue risk and maintenance costs while remaining adaptable to different planning horizons and decision-making preferences.

Environmental monitoring of La Concordia mine (Salta province, Argentina): assessing heavy metal bioaccumulation and physiological responses of Parastrephia quadrangularis.

The Puna region is distinguished by its extreme environmental conditions and highly valuable mining resources. However, the unregulated management of mine tailings poses a significant threat to the ecological integrity of this region. This study assesses the environmental impacts of mine tailings at La Concordia mine (Salta province, Argentina) and examines the physiological and biochemical adaptations of Parastrephia quadrangularis (Meyen) Cabrera that enable its survival under this extreme conditions. Our findings reveal that prolonged weathering of mine tailings results in the generation of acid mine drainage characterized by low pH levels (< 3.5) and elevated concentrations of As, Fe, Cu, Pb, and Zn. These levels exceed drinking water standards by 5-10 times for As, 6-13 times for Zn, 80-120 times for Pb, 20-380 times for Fe, and 4-10 times for Cu. Soil analyses highlight low pH, high salinity, and elevated concentrations of Zn (310mgkg-1), Pb (153mgkg-1), and Cu (128mgkg-1). Despite these harsh environmental conditions, 7 plant species where identified, with Parastrephia quadrangularis being the only species present at the most polluted site. This species exhibits high heavy metal bioaccumulation and robust tolerance mechanisms against heavy metal-induced oxidative damage, as evidenced by stable total chlorophylls and malondialdehyde content, and increased levels of carotenoids, proline, and phenolic compounds. These findings emphasize Parastrephia quadrangularis as a promising candidate for revegetation and phytostabilization for sustainable mine closure programs in La Puna region.

Evaluation of oat varieties for yield and disease resistance in the northern forest-steppe of the Novosibirsk Ob region

For the forest-steppe conditions of the Ob region with its sharply continental weather conditions, oat selection must combine high productivity of varieties with complex disease resistance. The purpose of the study is to evaluate oat varieties for disease resistance and adaptability in the northern forest-steppe of the Novosibirsk Ob region. The studies were conducted in 2018-2023. in the collection crop rotation and in the phytopathological section of the plant gene pool laboratory of SibNIIRS a branch of the Federal Research Center ICG SB RAS (located 17 km from Novosibirsk). The research material was 9 varieties of spring oats of Siberian origin (Krasnoobsky, Novosibirsky 5, Rovesnik, Sig, Orion, Otrada, Fakel, Sibirsky Hercules, Tobolyak). The varieties were assessed according to the following indicators: general adaptability to environmental conditions, resistance to extreme environmental conditions, stability of yield formation in contrasting conditions and resistance to three pathogens (red-brown spot, dusty and covered smut). High overall adaptability to environmental conditions was shown by: Fakel, Otrada, Tobolyak and Siberian Hercules (K = 1.07 1.04). The highest yield potential was formed by: Tobolyak (1359 g/m2), Otrada (1270 g/m2) and Orion (1236 g/m2). Resistance to stress (the smallest difference between maximum and minimum yields) had: Torch (-365 g/m2), Siberian Hercules (-420 g/m2). Compensatory ability (the highest average yield in contrasting conditions) is characterized by: Tobolyak (1090 g/m2), Fakel (987 g/m2) and Otrada (970 g/m2). Stable yields in contrasting conditions were demonstrated by: Fakel (31 %), Siberian Hercules (36 %) and Tobolyak (39 %). Complex resistance to three pathogens (red-brown spot, dusty and covered smut) was shown by: Siberian Hercules, Fakel and Novosibirsk 5.

Extremophilic hemoglobins: The structure of Shewanella benthica truncated hemoglobin N.

Truncated hemoglobins (TrHbs) have an ancient origin and are widely distributed in microorganisms where they often serve roles other than dioxygen transport and storage. In extremophiles, these small heme proteins must have features that secure function under challenging conditions: at minimum, they must be folded, retain the heme group, allow substrates to access the heme cavity, and maintain their quaternary structure if present and essential. The genome of the obligate psychropiezophile Shewanella benthica strain KT99 harbors a gene for a TrHb belonging to a little-studied clade of globins (subgroup 2 of group N). In the present work, we characterized the structure of this protein (SbHbN) with electronic absorption spectroscopy and X-ray crystallography, and inspected its structural integrity under hydrostatic pressure with NMR spectroscopy and small-angle X-ray scattering. We found that SbHbN self-associates weakly in solution and contains an extensive network of hydrophobic tunnels connecting the active site to the surface. Amino acid replacements at the dimeric interface formed by helices G and H in the crystal confirmed this region to be the site of intermolecular interactions. High hydrostatic pressure dissociated the assemblies while the porous subunits resisted unfolding and heme loss. Preservation of structural integrity under pressure is also observed in non-piezophilic TrHbs, which suggests that this ancient property is derived from functional requirements. Added to the inability of SbHbN to combine reversibly with dioxygen and a propensity to form heme d, the study broadens our perception of the TrHb lineage and the resistance of globins to extreme environmental conditions.

Increased Durability of Concrete Structures Under Severe Conditions Using Crystalline Admixtures

This study investigates the durability of concrete structures under severe environmental conditions, focusing on the effects of thermal stress, saline exposure, and seismic activity. The research employs a dual approach, combining laboratory experiments and field case studies to analyze various environmental impacts, mix designs, and the use of crystalline admixtures. Two concrete mix designs, CMD-01-C30/37 (mass concrete) and CMD-02-C35/45 (underwater concrete), were developed and tested for strength, permeability, and self-healing properties. The results demonstrate that both mix designs met or exceeded the required strength specifications, with improved resistance to water penetration and permeability depths lower than the code requirements set by European standards from EC2. The incorporation of crystalline admixtures in the mix designs significantly enhanced durability and performance, aligning with the priority of developing zero-carbon concrete solutions. The study also observed the self-healing capabilities of concrete treated with crystalline admixtures, as evidenced by the sealing of cracks at expansion and construction joints over time. These findings contribute to the development of a robust methodology for creating resilient structures adaptable to climate change, with potential implications for enhancing seismic resistance and structural longevity. The study underscores the importance of considering environmental factors and innovative admixtures in concrete design to improve durability and resilience, particularly in areas prone to seismic activity and extreme environmental conditions. Future research directions should focus on further investigating self-healing mechanisms, exploring the integration of durable and self-healing cement-based materials in engineering practice, and evaluating applications for both new construction and retrofitting existing structures.

Non-linear strain based FE model for free vibration analysis of stiffened functionally graded folded plates in hygrothermal environment

Stiffened functionally graded (FG) folded plates are being widely used these days in aeronautical, automotive, and naval applications which are often exposed to extreme environmental conditions characterized by high temperature and moisture concentrations. However, a numerical model to estimate the dynamic response of such structures in hygrothermal environment is almost non-existent. It is from this perspective that, a MATLAB-based finite element (FE) model is developed to assess the free vibration characteristics of stiffened FG folded panels in hygrothermal environment and is presented for the first time in this article. The governing equation is derived following the first order shear deformation theory including hygro-elastic and thermo-elastic relations. Temperature and moisture concentrations are assumed to vary both linearly and uniformly through the plate’s thickness to numerically simulate hygrothermal environment. Non-linear strains are incorporated in the present FE model to consider the hygrothermal effect. Another FE model is also developed in COMSOL Multiphysics software for these structures and is compared with the MATLAB-based model. Numerical simulations reveal that the free vibration characteristics of stiffened FG folded plates are significantly affected by hygrothermal environment. The present FE models can be effectively utilized by engineers and researchers to analyze and optimize the dynamic behavior of stiffened FG folded plates. The results are also expected to serve as a benchmark for future research works.

Assessing the impact of sewage and wastewater on antimicrobial resistance in nearshore Antarctic biofilms and sediments

BackgroundDespite being recognised as a global problem, our understanding of human-mediated antimicrobial resistance (AMR) spread to remote regions of the world is limited. Antarctica, often referred to as “the last great wilderness”, is experiencing increasing levels of human visitation through tourism and expansion of national scientific operations. Therefore, it is critical to assess the impact that these itinerant visitors have on the natural environment. This includes monitoring human-mediated AMR, particularly around population concentrations such as visitor sites and Antarctic research stations. This study takes a sequencing discovery-led approach to investigate levels and extent of AMR around the Rothera Research Station (operated by the UK) on the Antarctic Peninsula.ResultsAmplicon sequencing of biofilms and sediments from the vicinity of Rothera Research Station revealed highly variable and diverse microbial communities. Analysis of AMR genes generated from long-reads Nanopore MinION sequencing showed similar site variability in both drug class and resistance mechanism. Thus, no site sampled was more or less diverse than the other, either in the biofilm or sediment samples. Levels of enteric bacteria in biofilm and sediment samples were low at all sites, even in biofilm samples taken from the station sewage treatment plant (STP). It would appear that incorporation of released enteric bacteria in wastewater into more established biofilms or associations with sediment was poor. This was likely due to the inactivation and vulnerability of these bacteria to the extreme environmental conditions in Antarctica.ConclusionsOur results suggest minimal effect of a strong feeder source (i.e. sewage effluent) on biofilm and sediment microbial community composition, with each site developing its unique niche community. The factors producing these niche communities need elucidation, alongside studies evaluating Antarctic microbial physiologies. Our data from cultivated bacteria show that they are highly resilient to different environmental conditions and are likely to thrive in a warmer world. Our data show that AMR in the Antarctic marine environment is far more complex than previously thought. Thus, more work is required to understand the true extent of the Antarctic microbiota biodiversity, their associated resistomes and the impact that human activities have on the Antarctic environment.

Volcanic aerosols captured by plants: A study of nanoparticles and their chemical composition.

Nanoparticles (NPs) exhibit high reactivity and mobility in the environment, and a significant capacity to penetrate living organisms, potentially leading to harmful effects. Volcanoes are the second major source of natural NPs emitted into the atmosphere, with an estimated flux of 342 Tg/year. Few studies have focused on their fate. Thanks to technological advances in single-particle inductively coupled plasma mass spectrometry (spICP-MS), this trend is starting to reverse. La Soufrière volcano in Guadeloupe, chosen as a case study, exhibits increasing hydrothermal activity since its last eruption in 1530. This study aims to characterize NPs produced during volcanic activity by analysing ancient ash deposits, as well as those formed during periods of volcanic inactivity by examining condensates near fumaroles, as ultrafine particles are primarily generated through gas condensation. In this study, plants are utilized as samplers for NPs produced by fumarole activity. The use of a ICP-MS time-of-flight in single particle mode (spICP-ToF-MS), combined with data processing techniques such as hierarchical agglomerative clustering, enables the detailed characterization of NPs by determining their multi-element composition, concentration, and mass distribution. The results demonstrate that plants can effectively serve as samplers, even under the extreme environmental conditions present at the volcano's summit. However, differences in their efficiency at trapping particles on leaf surfaces can be attributed to varying physical characteristics of the plants. The spICP-ToF-MS analysis identified three types of multi-elemental NPs (NP-Al+Si, NP-Al+Fe, NP-Ti+Al) and three mono-elemental NPs (NP-Al, NP-Si, NP-Fe). Additionally, NPs containing trace elements were detected exclusively in undiluted Sphagnum pore water, where one tri-elemental NP (Sr-Ce-La), one bi-elemental NP (CeLa), and nine mono-elemental NP families (Cr, Cu, Zn, Sr, Y, Zr, Ba, La, Ce) were identified. Elements with potential negative effects on biota such as Cu, Zn, and Cr were also highlighted. Furthermore, the composition of the total of NPs (excluding families) is compared with elemental ratios from materials of different origins (volcanic, detrital, atmospheric) to validate their volcanic source.

Phylogeography of Antarctic soil invertebrate fauna reveals ancient origins, repeated colonization and recent evolution

Abstract Antarctica is populated by a diverse array of terrestrial fauna that have successfully adapted to its extreme environmental conditions. The origins and diversity of the taxa have been of continuous interest to ecologists since their discovery. Early theory considered contemporary populations as descendants of recent arrivals; however, mounting molecular evidence points to firmly established indigenous taxa far earlier than the Last Glacial Maximum, thus indicating more ancient origins. Here we present insights into Antarctica's terrestrial invertebrates by synthesizing available phylogeographic studies. Molecular dating supports ancient origins for most indigenous taxa, including Acari (up to 100 million years ago; Ma), Collembola (21–11 Ma), Nematoda (~30 Ma), Tardigrada (&gt; 1 Ma) and Chironomidae (&gt; 49 Ma), while Rotifera appear to be more recent colonizers (~130 Ka). Subsequent population bottlenecks and rapid speciation have occurred with limited gene transfer between Continental and Maritime Antarctica, while repeated wind- or water-borne dispersal and colonization of contiguous regions during interglacial periods shaped current distributions. Greater knowledge of Antarctica's fauna will focus conservation efforts to ensure their persistence.

Ecological and Functional Changes in the Hindgut Microbiome of Holstein Cows at High Altitudes.

The extreme environmental conditions of the Qinhai-Tibetan Plateau (QTP) challenge livestock survival and productivity, yet little is known about how high-altitude environments impact the gut microbiota of dairy cows. To fill this gap, we systematically investigated the differences in the hindgut microbiome between 87 plateau Holstein cows and 72 plain Holstein cows using 16S rRNA gene sequencing. Our analysis revealed that the hindgut microbiota of the plateau group exhibited lower species richness but higher evenness than that in the plain group. Additionally, significant separation in hindgut microbiota composition between the two groups was observed based on altitude, while parity, days in milk, and age did not show a comparable impact. Moreover, altitude had a lasting impact on bacterial communities and their co-occurrence networks, resulting in reduced microbial interactions and lower modularity in the plateau group. Furthermore, we identified four key microbial taxa, the Bacteroidaceae and Rikenellaceae families, as well as the Prevotella and Treponema genera, which were associated with the regulation of carbohydrate digestion and energy metabolism and might help the Holstein cows adapt to the plateau environment. Our findings provide insights into strategies for enhancing the adaptability of dairy cows to high-altitude environments through microbiota modulation, which could ultimately contribute to improving livestock management and sustainability in these extreme environments.

Characterization and Modelling of Potential Seaborne Disasters, in the ANA Region

Shipping activities continue to experience growth across a multitude of industrial sectors within the Arctic, hence there are risks in terms of severity and likelihood of accidents. The Arctic region is inherently dangerous to transportation and human existence due to its extreme climate and environmental conditions, and hence the complexities associated with emergency situations within the maritime domain are amplified when operating within the Arctic and North-Atlantic (ANA). The definition and characterisation of potential seaborne disasters and catastrophic incidents in the ANA region are significant enablers in providing a set of critical and sustainable tools for Search and Rescue (SAR), Oil Spill Response (OSR), and emergency management practitioners. Therefore, in this paper we aim to identify and characterise high-priority potential seaborne disasters and catastrophic incidents in the ANA region such as cruise ship accidents, oil leaks, radiological leaks, and fishing boat groundings. These were compiled as an outcome of a set of workshops carried out as part of the ARCSAR, EU Horizon 2020 funded project , and from analysis of the literature. We also provide root cause analysis techniques, tools for strategic decision-making, and means of mitigation. We demonstrate how such tools can be used by applying some of them to a selective case study and drawing lessons learned from the application of root cause analysis, which can help emergency response organisations with preparedness work and hence more efficient response. In doing so, we provide a set of tools that can be used for strategic and operational learning. Such approaches can help standardise the definition and characterisation of potential seaborne disasters and catastrophic incidents in the ANA region in both prospective and retrospective analysis.

Rooting for microbes: impact of root architecture on the microbial community and function in top- and subsoil

Abstract Background and aims Climate change and associated weather extremes pose major challenges to agricultural food production, necessitating the development of more resilient agricultural systems. Adapting cropping systems to cope with extreme environmental conditions is a critical challenge. This study investigates the influence of contrasting root system architectures on microbial communities and functions in top- and subsoil. Methods A column experiment was performed to investigate the effects of different root architectures, specifically deep (DRS) and shallow (SRS) root systems of wheat (Triticum aestivum L.) on microbial biomass, major microbial groups, and extracellular enzyme activities in soil. We focused on β-glucosidase (BG) activity, which is an indicator for microbial activity, during different plant growth stages, using destructive and non-destructive approaches. Results We found that the DRS promoted microbial biomass and enzyme activity in subsoil, while the SRS increased the microbial biomass and enzyme activity in topsoil. In-situ soil zymography provided fine-scale spatial insights, highlighting distinct patterns of BG activity near root centers and formation of enzyme activity hotspots, which were defined as regions where enzyme activity exceeds the mean activity level by 50%. Temporal changes in BG activity further underscored the dynamic nature of root-microbe interactions. Extracellular enzyme activities indicated varying carbon, nitrogen and phosphorus acquisition strategies of rhizosphere microorganisms between top- and subsoil. Conclusion This study underscores the need to consider root system architecture in agricultural strategies, as it plays a crucial role in influencing microbial communities and enzyme activities, ultimately affecting carbon and nutrient cycling processes in top- and subsoil.

Molecular Phylogeny and Morphology Reveal Four New Species of Conocybe (Bolbitiaceae, Agaricales) from the Qinghai-Xizang Plateau, China.

The Qinghai-Xizang Plateau, known for its high altitude, geological history of plate collision, crustal uplift, and special ecology factors, provides an ideal environment for studying fungal biodiversity in extreme environmental conditions. Some species within the Conocybe, containing secondary metabolites such as psilocybin, phallotoxins, and amatoxins, have potential medicinal value for treating psychiatric disorders and for use in drug development. This study investigates Conocybe (Bolbitiaceae, Agaricales) on the Plateau, based on specimens collected over the past decade, using morphological and molecular phylogenetic analyses. Seven species were identified, including four new species: C. alticola, C. alticoprophila, C. versicolor, and C. yadongensis. Molecular analyses, utilizing multi-gene sequence data (ITS, nrLSU, and tef-1α), support the taxonomic position of these new species within this genus as new species. Detailed descriptions, illustrations, photographs, line drawings, and comparisons with related species are provided for the new taxa. This study enriches the species diversity of Conocybe on the Qinghai-Tibet Plateau, further enhancing our understanding of fungal biodiversity in this region.

A Quantitative Analysis of Internal and External Loads in Aviation Firefighting Using a Simulated Scenario.

Aviation firefighting is a strenuous occupation that requires individuals to engage in intense physical activity amidst elevated stress levels and extreme environmental conditions. Despite this, there has been limited investigation regarding the internal and external loads associated with aviation firefighting tasks, which include hose dragging, stair climbing, casualty evacuation, and fire extinguishing in airports and aircrafts. The aim of this study was to examine the internal and external loads placed on aviation firefighters. By identifying these demands, this study seeks to inform the development of targeted training strategies, improve job safety, and lower the risk of musculoskeletal injuries. Sixteen Australian aviation firefighters (35.13 ± 8.2 years) were recruited and assigned specific roles to complete an aircraft firefighting scenario. Measures of heart rate (HR), oxygen consumption (V˙O2), and rating of perceived exertion (RPE) were used to quantify internal load, while measures of completion time and distance travelled were used to quantify external load. The median scenario completion time was 21 min (IQR = 5), with each role travelling a median distance of 245-541 m. During the scenario, median average HR values ranged between 61.1 and 72.0% HRmax and median maximal HR values ranged between 77.8 and 84.4% HRmax. As the only group to record V˙O2, driver firefighters operated at a median average V˙O2 of 49% of their V˙O2max and achieved a median maximal V˙O2 of 78% of their V˙O2max. This study effectively identified the task-specific internal and external loads associated with aviation firefighting, offering valuable insights for developing specific training protocols for firefighters to ensure appropriate physical capacity to perform their job roles safely.