Human disturbance in the Arctic is increasing. Abrupt changes in vegetation may be expected, especially when spots without vegetation are made available; additionally, climate change alters competition between species. We studied whether 34- to 35-year-old seismic operations had left imprints on local vegetation and whether changes could be related to different soil characteristics. The study took place in Jameson Land in central east Greenland where winter seismic operations in search of oil took place from 1985 to 1989. This area is dominated by continuous dwarf shrub heath with Cassiope tetragona, Betula nana, and Vaccinium uliginosum as dominant species. Using point frame analyses, we registered vascular plants and other surface types in frames along 10-m transects in vehicle tracks (hereafter damages) and in undisturbed vegetation parallel to the track (hereafter references) at eleven study sites. We also measured temperature and pH and took soil samples for analysis. Damaged and reference vegetation types were compared with S & oslash;rensen similarity indices and detrended correspondence analyses. Although most vascular plant species were equally present in damaged vegetation and in references the detrended correspondence analyses showed that at ten out of eleven study sites the damages and references still differed from each other. Graminoids and the herb Polygonum viviparum had the highest occurrence in damages. Shrubs and the graminoid Kobresia myosuroides had the highest occurrence in references. Cassiope tetragona was negatively impacted where vehicles had compacted the snow. Moss, organic crust or biocrust, soil, and sand occurred more often in damages than in references, whereas lichens and litter had the highest occurrence in references. The richness of vascular plant species varied between the eleven study sites, but between damages and references the difference was only up to four species. Temperature was the soil parameter with the most significant differences between damages and references. Total recovery of the damaged vegetation will most likely not occur within several decades. The environmental regulations were important to avoid more serious impacts.
Bats are indispensable members of the natural world, supporting its delicate balance. Bats have vital roles in controlling insect populations and enhancing soil fertility. They also help in the harvesting and dispersal of seeds, pollination in plants, and nutrient recycling and distribution. However, through evolution over millions of years, they have also adapted their immune system so that they may carry numerous types of pathogens, the majority of which are viruses, without these pathogens having any serious ill effects on bats themselves. Their anatomical adaptation to flight and the reduced immune response to DNA damage during flight have also contributed to bats becoming reservoirs of deadly pathogenic diseases. This review discusses the different adaptations of bats with a special focus on the immune system that have helped them evolve as a reservoir for various viruses. The study also enumerates how the increase in global warming, the consequent changes in climatic conditions, habitat destruction, and bushmeat consumption increase the chances of an outbreak of novel zoonotic disease when humans come in contact with bats.
Permafrost degradation on the Tibetan Plateau (TP) has triggered widespread retrogressive thaw slumps (RTSs), affecting hydrology, carbon sequestration and infrastructure stability. To date, there is still a lack of long-term monitoring of RTSs across the TP, the thaw dynamics and comprehensive driving factors remain unclear. Here, using time-series Landsat imagery and change detection algorithm, we identified RTSs on permafrost regions of the TP from 1986 to 2020. Existing RTSs inventories and high-resolution historical imagery were employed to verify the identified results, the temporal validation of RTSs disturbance pixels demonstrated a high accuracy. In the study area, a total of 3537 RTSs were identified, covering a total area of 5997 ha, representing a 26-fold increase since 1986, and 69.2 % of RTSs formed since 2010. Most RTSs are located on gentle slope (4-12 degrees) at elevations between 4500 m and 5300 m, with a tendency to form in alpine grassland and alpine meadow. Annual variations in RTSs area exhibited a significant positive correlation with minimum air temperature, mean land surface temperature, and annual thawing index, while it showing a significant negative correlation with the decrease in downward shortwave radiation. Spatially, RTSs were more common in areas with higher soil water content and shallower active layer. Landsat imagery captured the vast majority of RTSs on the TP and revealed interannual disturbance details, but the 30 m resolution remains inadequate for delineating the refined boundaries of some micro-scale (< 0.18 ha) RTSs. Detected RTSs disturbances on the TP will aid in hazard management and carbon feedback assessments, and our findings provide novel insights into the impacts of climate change and permafrost environments on RTSs formation.
Rare earth elements (REEs) are a type of frequently reported emerging pollutant that affects plant growth. The harm caused by continuous exposure to low-dose REEs has rarely been studied. Quickly, accurately, and noninvasively monitoring the continuous influence of low-dose REEs on plant growth in situ is key to indicating and warning of its harm to plants and ecosystems. In this study, after continuous exposure to low-dose lanthanum [La(III), a REE] for 14 days, invisible damage occurred in leaf cells, and La accumulated continuously in the soybean plants (leaves > stems > roots > pods > seeds), causing potential human health risks. Two proteins [vitronectin-like protein (VN) and arabinogalactan proteins (AGP)] in leaf cells that bound La(III) were selected as biomarkers, and changes in these two proteins were detected by constructing dual-sensors in living leaf cells after continuous exposure to low-dose La(III) for 14 days. The results showed that the electrochemical outputs from leaf cells-the electron transfer resistance Ret(VN) and Ret(AGP)-were related to the damage indices such as MDA, chlorophyll content, electrolyte leakage, cell vitality, fresh and dry weight of leaves, and leaf area. Using this output, two warning intervals of visible damage were obtained: Ret(VN) was 8.53 %-47.22 %, and Ret(AGP) was 12.75 %-51.31 %. This study successfully demonstrated the real-time in situ detection of plant cell biomarker changes and invisible damage under low-dose La(III) exposure, providing methods for early warning monitoring of plant damage caused by low-dose continuous exposure to REEs.
Waves can cause significant accumulation of pore water pressure and liquefaction in seabed soils, leading to instability of foundations of marine hydrokinetic devices (MHKs). Geostatic shear stresses (existing around foundations, within slopes, etc.) can substantially alter the rate of pore pressure buildup, further complicating the liquefaction susceptibility assessments. In this study, the development of wave-induced residual pore water pressure and liquefaction within sandy seabed slopes supporting MHK structures is evaluated. Unlike most earlier studies that excluded the impact of shear stress ratios (SSR) on the residual pore pressure response of sloping seabeds, asymmetrical cyclic loadings are considered herein for a range of SSRs. To obtain wave-induced loading in the seabed (and cyclic shear stress ratios, CSRs), the poroelasticity equations governing the seabed response, coupled with those for fluid and structure domains, are solved simultaneously. Utilizing an experimental model based on anisotropic cyclic triaxial test data that includes CSR and SSR impacts, an equation for the rate of pore pressure buildup is developed and added as a source term to the 2D consolidation equation. Numerical investigations were performed by developing finite element models in time domain. The models were calibrated using particle swarm optimization method and validated against wave flume experimental data. The results indicate that the consideration of static shear stresses has led to sudden rise in residual pore pressures followed by fast dissipations at early and late time steps, respectively, beneath the structure. The exclusion of SSR is shown to cause significant overestimation of pore pressure accumulations at late cycles, potentially causing significant overdesign of MHK foundations. The impact of proximity to the free drainage boundary, CSR amplitude, and loading frequency on the accumulation of residual pore pressure is illustrated. The residual liquefaction susceptibility of the seabed is shown to decline by increase of the seabed slope angle.
The present work introduces an analytical framework based on the limit-equilibrium method for the determination of the local factor of safety (FS) and global factor of safety (FSG), and local displacements along the critical slip surface using the Morgenstern-Price (MP) method of slices. This proposed work computes displacements along the critical slip surface in addition to a single FSG. The unsaturated shear strength models, in conjunction with the soil-water characteristic curve (SWCC), are considered. The MP-based equilibrium equations to determine FSG are utilized as an objective function in the metaheuristic search algorithm of particle swarm optimization to determine the critical center, critical radius, and minimum FSG for unsaturated finite slopes. It is recommended to use a particle size of 75 and conduct 50 iterations for optimal results. The effects of SWCC fitting parameters on the critical slip surface, FSG, point FS, and point displacements are also investigated. Two distinct benchmark slope scenarios with and without negative pore water considerations are utilized in the current study. This approach enables a detailed investigation into the influence of various unsaturated soil parameters, such as af (related to the air-entry value), nf (related to the slope of the SWCC), and mf (related to the residual water content), as well as constitutive model parameters including the linear shear modulus (G) and the fitting parameter (rho). The maximum displacement occurs at the slope's top crest. Under benchmark conditions, the first scenario shows a reduction in point displacement by 3.30%, 1.98%, and 10.23% for SWCC-1, SWCC-2, and SWCC-3, respectively. However, in the second scenario with SWCC-3, the critical slip surface's position changes, affecting local displacements. This results in an increase of 32.72% (i.e., from 21.45 to 28.47 mm) in point displacement at the top when comparing SWCC-3 with no SWCC consideration. The current study advocates that the effect of fitting parameters of the SWCC should be used to better understand the local FS and displacement, because the critical slip surface is contingent on the values of the SWCC. Ignoring SWCC parameters can lead to an underestimation of slope displacement, because they significantly influence the critical slip surface position and displacement magnitude. Their inclusion is essential for accurately assessing slope stability and preventing errors in displacement prediction.
To enhance the safety and reliability of urban buried water supply networks, this study developed a monitoring and early warning system based on wireless transmission networks and Internet of Things (IoT) technology. Through numerical simulations, the structural tilt warning thresholds for ductile iron pipes were determined. Additionally, in conjunction with meteorological data, monitoring pore water pressure serves as a supplementary indicator for detecting potential pipeline leakage. This study further analyzed pipeline strength warning thresholds based on strength theory. In practical engineering applications, the proposed system enables real-time monitoring of the operational status, service environment, and structural integrity of buried water supply networks. Data analysis revealed the influence mechanisms of backfill soil conditions, daily operations, and third-party construction activities on the structural behavior and stress state of water supply pipelines. Results indicate that during the initial backfilling phase, uneven backfilling and soil settlement induce significant variations in pipeline tilt angle and stress distribution. Furthermore, longitudinal stress in the pipeline exhibits a strong correlation with ambient temperature fluctuations, with a pronounced increase observed during colder months. Notably, third-party construction activities were identified as a major contributor to pipeline anomalies, with all recorded early warnings in this study being attributed to such external interferences.
The southern regions of China are rich in ion-adsorbed rare earth mineral resources, primarily distributed in ecologically fragile red soil hilly areas. Recent decades of mining activities have caused severe environmental damage, exacerbating ecological security (ES) risks due to the inherent fragility of the red soil hilly terrain. However, the mechanisms through which multiple interacting factors influence the ES of rare earth mining areas (REMA) remain unclear, and an effective methodological framework to evaluate these interactions dynamically is still lacking. To address these challenges, this study develops an innovative dynamic ES evaluation and earlywarning simulation framework, integrating Variable Weight (VW) theory and the Bayesian Network (BN) model. This framework enhances cross-stage comparability and adapts to evolving ecological conditions while leveraging the BN model's diagnostic inference capabilities for precise ES predictions. A case study was conducted in the Lingbei REMA. The main findings of the study are as follows: (1) From 2000 to 2020, the overall ES of the mining area exhibited a dynamic trend of deterioration, followed by improvement, and ultimately stabilization. (2) Scenario S27 (high vegetation health status and high per capita green space coverage) significantly reduces the probability of the ES reaching the extreme warning level. (3) The evaluation and simulation framework developed in this study provides a more accurate representation of the ES level distribution and its variations, with probabilistic predictions of ES demonstrating high accuracy. This study is of great significance for improving regional ES, supporting the optimization of ecological restoration strategies under multi-objective scenarios, and promoting the coordinated development of nature and resource utilization.
Cycas panzhihuaensis inhabits regions where summer temperatures can exceed 40 degrees C, and these extreme conditions may intensify with ongoing global warming. However, how this species adapts to such thermal extremes is not well understood. To investigate the responses of C. panzhihuaensis to heat stress, some physiological characteristics along with lipid and fatty acid profiles were analyzed. The results show that heat stress induced soil water loss but did not cause leaf water loss and visible symptoms of leaf damage. However, photoinhibition was induced and heat dissipation was inhibited under the stress. In the recovered plants, both heat dissipation and maximum photochemical efficiency exhibited significant increases compared to the stressed plants but did not return to the control level. Most lipid categories including phospholipids and saccharolipids accumulated significantly following both the stress and subsequent recovery. However, the content of total neutral glycerolipids maintained unchanged after various treatments. The ratio of phosphatidylcholine/phosphatidylethanolamine decreased significantly and the ratios of both digalactosyldiacylglycerol/monogalactosyldiacylglycerol and triacylglycerol/diacylglycerol increased significantly in the stressed plants. Compared to the control plants, the relative content of polyunsaturated fatty acids significantly increased, while that of both saturated and monounsaturated fatty acids significantly declined in both stressed and recovered plants. Under stress conditions, the unsaturation levels of total neutral glycerolipids and their constituent components significantly increased, whereas those of phosphatidylglycerol and total saccharolipids exhibited a marked decrease. In conclusion, C. panzhihuaensis can tolerate extremely high temperatures to some extent which might be associated with the adjustments in lipid composition and unsaturation levels.
A heavy armed conflict erupted in Tigray region of Ethiopia in 2020, and the crisis continued up to 2022. This study investigates the impacts of this crisis on the status of natural resources, and Soil and Water Conservation (SWC) efforts. We collected primary data through field observations, measurements, interviews and group discussions during the wartime. We also reviewed published articles and official archives to complement the primary data, which were often challenging to obtain due to the war. We found that vegetated landscapes were damaged by artillery fire and bombings. The average depth of the surveyed bomb craters along the asphalts was 1.15 +/- 0.47 m (n 1/4 16), whereas the average surface diameter of the craters and their rim was 2.66 +/- 0.67 m. In addition, the construction of numerous military trenches along croplands and hillsides exposed the soil particles into erosion and water pollution. The conflict also halted SWC efforts on various land uses, which were carried out annually during peacetime. For instance, 20,591 km/year of stone bunds were not constructed per year due to the crisis. Moreover, terraces and stone bunds were demolished to construct temporary ground fortifications. Indirectly, the critical energy crisis further increased pressure on forests. In this context, the poor farmers shift their livelihood strategies from the long-term sustainability to immediate economic recovery during the critical time. To conclude, the pathways of the warfare undermined the status of natural resources, and the ongoing decades of re-greening programs. Therefore, our ground-based findings can be used to prioritize and rehabilitate the war-damaged landscape services. (c) 2024 International Research and Training Center on Erosion and Sedimentation, China Water and Power Press, and China Institute of Water Resources and Hydropower Research. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY- NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).