Search Results (3,319)

Understanding the spatiotemporal dynamics of coastal intertidal meta-ecosystems in response to sea-level rise (SLR) is essential for understanding the interactions between terrestrial and aquatic meta-ecosystems. However, given that annual SLR changes are typically measured in millimeters, ecosystems may take decades to exhibit noticeable shifts. As a result, the extent of lateral responses at a single point is constrained by the fragmented temporal and spatial scales. We integrated the tidal inundation gradient of a coastal meta-ecosystem—comprising a high-elevation flat (H), low-elevation flat (L), and mudflat—to quantify the potential application of inferring the spatiotemporal impact of environmental features, using China’s Yangtze Estuary, which is one of the largest and most dynamic estuaries in the world. We employed both flood ratio data and tidal elevation modeling, underscoring the utility of spatial modeling of the role of SLR. Our results show that along the tidal inundation gradient, SLR alters hydrological dynamics, leading to environmental changes such as reduced aboveground biomass, increased plant diversity, decreased total soil, carbon, and nitrogen, and a lower leaf area index (LAI). Furthermore, composite indices combining the enhanced vegetation index (EVI) and the land surface water index (LSWI) were used to characterize the rapid responses of vegetation and soil between sites to predict future ecosystem shifts in environmental properties over time due to SLR. To effectively capture both vegetation characteristics and the soil surface water content, we propose the use of the ratio and difference between the EVI and LSWI as a composite indicator (ELR), which effectively reflects vegetation responses to SLR, with high-elevation sites driven by tides and high ELRs. The EVI-LSWI difference (ELD) was also found to be effective for detecting flood dynamics and vegetation along the tidal inundation gradient. Our findings offer a heuristic scenario of the response of coastal intertidal meta-ecosystems in the Yangtze Estuary to SLR and provide valuable insights for conservation strategies in the context of climate change. Full article

The transition toward renewable-powered greenhouse agriculture offers opportunities for reducing operational costs and environmental impacts, yet challenges remain in managing fluctuating energy loads and optimizing agricultural inputs. While second-life lithium-ion batteries provide a cost-effective energy storage option, their thermal and electrical characteristics under real-world greenhouse conditions are poorly documented. Similarly, although plasma-activated water (PAW) shows potential to reduce chemical fertilizer usage, its integration with renewable-powered systems requires further investigation. This study develops an adaptive monitoring and modeling framework to estimate the thermal resistances (R_u, R_c) and internal resistance (R_int) of second-life lithium-ion batteries using operational data from greenhouse applications, alongside a field trial assessing PAW effects on beefsteak tomato cultivation. The adaptive control algorithm accurately estimated surface temperature (T_s) and core temperature (T_c), achieving a root mean square error (RMSE) of 0.31 °C, a mean absolute error (MAE) of 0.25 °C, and a percentage error of 0.31%. Thermal resistance values stabilized at R_u ≈ 3.00 °C/W (surface to ambient) and R_c ≈ 2.00 °C/W (core to surface), indicating stable thermal regulation under load variations. Internal resistance (R_int) maintained a baseline of ~1.0–1.2 Ω, with peaks up to 12 Ω during load transitions, confirming the importance of continuous monitoring for performance and degradation prevention in second-life applications. The PAW treatment reduced chemical nitrogen fertilizer use by 31.2% without decreasing total nitrogen availability (69.5 mg/L). The NO₃⁻-N concentration in PAW reached 134 mg/L, with an initial pH of 3.04 neutralized before application, ensuring no adverse effects on germination or growth. Leaf nutrient analysis showed lower nitrogen (1.83% vs. 2.28%) and potassium (1.66% vs. 2.17%) compared to the control, but higher magnesium content (0.59% vs. 0.37%), meeting Japanese adequacy standards. The total yield was 7.8 kg/m², with fruit quality comparable between the PAW and control groups. The integration of adaptive battery monitoring with PAW irrigation demonstrates a practical pathway toward energy efficient and sustainable greenhouse operations. Full article

Climate change and injudicious nitrogen addition alter the soil physico-chemical properties and microbial activity in oligotrophic forest soil, which disrupts the nitrogen cycle balance. Nevertheless, recommended fertilizer forms and levels are considered to be crucial for stable nitrogen application. We established a short-term field trial for the first time using a randomized complete block design under the yellow larch forest, with six treatments applied, including urea CO(NH₂)₂, ammonium chloride NH₄Cl, and sodium nitrate NaNO₃ at concentrations of 10 and 20 kg N hm⁻² yr⁻¹, each extended by three replicates. The gene abundances were measured using quantitative PCR (qPCR), in which the abundance levels of AOA (amoA) and nirS were higher under high CO(NH₂)₂ 2.87 × 10¹⁰ copies g⁻¹ dry soil and low NO₃⁻ 8.82 × 10⁹ copies g⁻¹ dry soil, compared to CK, representing 2.8-fold and 1.5-fold increases, respectively. We found niche partitioning as revealed despite AOA (amoA) increasing in number, AOB (amoA) contributing more to ammonia oxidation while nirS proved opportunistic under stress conditions. This was supported by distinct significant correlations among factors, in which soil urease enzymatic activity (S-UE) was associated with AOA (amoA) and nirK, while AOB (amoA) and nirS positively correlated with NH₄⁺ content and soil potential of hydrogen (pH), respectively. Among the applied treatments, high-level NO₃⁻ increased total nitrogen content and had a significant effect on soil N-acetyl-β-d-glucosaminidase (S-NAG) and soil acid protease (S-ACPT) activity. In summary, we observed an increase in Larix olgensis growth with high nitrogen retention. Full article

The Sanqi–pine agroforestry (SPA) system is considered a sustainable agroforestry model. However, empirical studies that clearly elucidate the impact of Sanqi cultivation on soil fertility and the heavy metal content within the SPA system are still lacking. This study established monoculture Pinus armandii (MPA) and SPA systems to conduct a comparative analysis of dynamic changes in soil physicochemical properties and the heavy metal content of Sanqi and pine over one year (with semi-monthly sampling), followed by a comprehensive evaluation of soil fertility and heavy metal pollution. Following the land use conversion from MPA to SPA, there was a notable increase in soil moisture (SM), total nitrogen (TN), and nitrate nitrogen (NO₃⁻-N) levels within Sanqi soil. Conversely, total potassium (TK), ammonium nitrogen (NH₄⁺-N), plumbum (Pb), and chromium (Cr) levels experienced a significant reduction. In the case of pine soil, soil moisture (SM), pH levels, and ammonium nitrogen (NH₄⁺-N) content exhibited an increase. However, soil organic carbon (SOC), total phosphorus (TP), total potassium (TK), zinc (Zn), manganese (Mn), plumbum (Pb), and chromium (Cr) contents all significantly decreased. The Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) demonstrated that Sanqi cultivation not only significantly enhanced soil fertility for Sanqi rather than pine but also reduced the heavy metal content in the soil of both Sanqi and pine within the SPA system. Furthermore, the Nemerow pollution index for both Sanqi and pine soils has decreased, transitioning the pollution status from relatively safe to safe. This suggests that the introduction of Sanqi promotes the sustainable development of the SPA system. Full article

The ecotoxicity induced by macrolides has attracted widespread attention, but their impacts on the nitrogen metabolism and symbiotic environmental bacteria of microalgae remain unclear. This study examined the effects of roxithromycin (ROX) on the growth, chlorophyll levels, and nitrogen metabolism of Chlorella pyrenoidosa; investigated the changes in the composition and functions of environmental bacterial communities; and finally, analyzed the relationship between microalgae and environmental bacteria. The results indicated that all concentrations of ROX (0.1, 0.25, and 1 mg/L) inhibited microalgae growth, but the inhibition rates gradually decreased after a certain exposure period. For instance, the inhibition rate in the 1 mg/L treatment group reached the highest value of 43.43% at 7 d, which then decreased to 18.93% at 21 d. Although the total chlorophyll content was slightly inhibited by 1 mg/L ROX, the Chl-a/Chl-b value increased between 3 and 21 d. The nitrate reductase activities in the three treatments were inhibited at 3 d, but gradually returned to normal levels and even exceeded that of the control group at 21 d. Under ROX treatment, the consumption of NO₃⁻ by microalgae corresponded to the nitrate reductase activity, with slower consumption in the early stage and no obvious difference from the control group in the later stage. Overall, the diversity of environmental bacteria did not undergo significant changes, but the abundance of some specific bacteria increased, such as nitrogen-fixing bacteria (unclassified-f-Rhizobiaceae and Mesorhizobium) and organic contaminant-degrading bacteria (Limnobacter, Sphingopyxis, and Aquimonas). The 0.25 and 1 mg/L ROX treatments significantly enhanced the carbohydrate metabolism, cofactor and vitamin metabolism, amino acid metabolism, and energy metabolism of the environmental bacteria, but significantly downregulated nitrogen denitrification. This study provides new insights into the environmental bacteria-driven recovery mechanism of microalgae under antibiotic stress. Full article

White clover (Trifolium repens L.) is known for its ability to fix nitrogen biologically, its high nutritional value, and its adaptability to livestock systems. However, excessive fertilization with synthetic nitrogen alters its symbiosis with Rhizobium and reduces the protein content of the forage. The objective of this study was to evaluate the interaction between nitrogen fertilization (0 and 60 kg N ha⁻¹), cutting time, and post-cutting evaluation on the morphology, yield, and nutritional composition of white clover. A completely randomized block experimental design with three factors, distributed in three blocks, was used. Within each block, three replicates of each treatment were assigned (six interactions), giving a total of 54 experimental units. The data were analyzed using a three-way analysis of variance and Tukey’s multiple comparison test. Exponential models and generalized additive models (GAMs) were applied to the morphology and yield data to identify the best fit. The treatment with 60 kg N ha⁻¹ and cutting at 30 days showed significant increases in plant height (47.42%), fresh weight (59.61%), dry weight (98.41%), and leaf width (27.55%) compared to the control. It also produced the highest protein content (28.44%) compared to the other treatments with fertilization, without negatively affecting digestibility. The GAMs best fit most morphological and yield parameters (except leaf height and width). All fertilized treatments had higher fresh and dry weight yields. In conclusion, applying 60 kg N ha⁻¹ after cutting at 30 days, followed by harvesting between 54 and 60 days, improved both the quality and yield of white clover, which favored sustainable pasture management and reduced excessive nitrogen use. Full article

The prevalence of hyperuricemia with elevated serum uric acid is increasing worldwide. However, the effects of high uric acid on diabetic patients with dyslipidemia and the mechanisms underlying these effects remain unexplored. This study aimed to develop a novel diabetic model of hyperuricemia and dyslipidemia in male hamsters to evaluate the effects of high uric acid on glucolipid metabolism, renal injury and the gut microbiota. Twelve healthy hamsters were randomly divided into two groups and fed with a normal diet and high-fat/cholesterol diet (HFCD), respectively. Twenty-four diabetic hamsters were randomly divided into four groups receiving a normal diet; HFCD; potassium oxonate (PO) treatment (intragastric PO at doses of 350 mg/kg and adenine at doses of 150 mg/kg with 5% fructose water); and PO treatment with HFCD, respectively. After 4 weeks, all animals were dissected for determining serum biochemical indicators, tissue antioxidant parameters, renal pathological changes, target gene expressions, fecal short-chain fatty acids content, and the gut microbiota composition. The results showed that a hamster model with hyperuricemia and dyslipidemia was successively established by the combination of PO treatment and HFCD, in which serum uric acid, glucose, triglyceride and total cholesterol levels reached 499.5 ± 61.96 μmol/L, 16.88 ± 2.81 mmol/L, 119.88 ± 27.14 mmol/L and 72.92 ± 16.62 mmol/L, respectively. PO treatment and HFCD had synergistic effects on increasing uric acid, urea nitrogen, creatinine levels, liver xanthine oxidase activity, plasminogen activator inhibitor-1 and transforming growth factor-β expressions, and the relative abundance of Lleibacterium (p < 0.05); in addition, they caused glomerular mesangial cells and matrix proliferation, protein casts and urate deposition. High uric acid was closely related to decreased antioxidant capacity; decreased renal vascular endothelial growth factor expression; increased acetic acid content; decreased butyric, propanoic, and isobutyric acid levels; decreased Firmicutes to Bacteroidetes ratios (p < 0.05); and altered epithelial integrity and structure of the gut microbiota in diabetic hamsters. The findings indicate that high uric acid affects the glucolipid metabolism, accelerates renal damage, and disrupts the balance of intestinal flora in diabetic animals, which provides a scientific basis for metabolic syndrome prevention and control in diabetes. Full article

As low temperature is a key factor affecting the growth and development of plants and the utilization of agricultural waste has significant research value, this study explores the effects of 16 agricultural wastes on the growth of P. fraseri under natural low-temperature conditions and evaluates its cold resistance capacity. Soil chemical properties were analyzed and all the wastes were found to exhibit alkalinity. The highest total nitrogen content was found in group A (garden soil/coir/municipal sludge = 7:1:2). In this group, the branch number, branch length, and branch diameter were the largest. Interestingly, the plants in group E (garden soil/coir/pig manure = 7:1:2) had the highest average number of new shoots, with 5.72. Analysis of the physiological indexes of leaves revealed that the proline content, superoxide dismutase activity, fresh weight, and dry weight of plants in group L (garden soil/coir/pear residue = 7:1:2) were the highest. The stomatal conductance and transpiration rate of the leaves of plants in group L were the largest, at 86.23 mmol∙m⁻²∙s⁻¹ and 1.67 mmol∙m⁻²∙s⁻¹, respectively. Furthermore, combined with morphological and physiological indicators for membership function analysis, the results show that plants in group A exhibited optimal growth under natural low temperature. Correlation analysis indicated varying degrees of correlation between 38 pairs of indicators, including branch number and branch length, intercellular CO₂ concentration and stomatal conductance, and leaf fresh weight and dry weight. Heatmap analysis showed that branch number, branch length, and branch diameter were highest in group A plants, while the highest levels of proline occurred in group L plants. In this study, groups A and L are recommended for growth under naturally low-temperature conditions. Full article

Plant growth-promoting rhizobacteria (PGPR) are microorganisms that enhance plant growth through various mechanisms. In the context of global agriculture, which faces fertilizer dependency and environmental pollution, developing eco-friendly microbial fertilizers has become crucial for enhancing agricultural sustainability. To identify highly effective PGPR, we isolated 102 bacterial strains from maize rhizosphere soil using the dilution plating method. The strains were screened for growth-promoting abilities using functional media, resulting in the selection of strain YMK25 for its exceptional capabilities in nitrogen fixation, solubilization of inorganic and organic phosphorus, indole-3-acetic acid (IAA) production, and siderophore production. Strain YMK25 produced IAA at a concentration of 80.49 ± 0.68 μg/mL and exhibited a relative siderophore expression level of 43.68%. Morphological analysis, 16S rDNA gene sequence analysis, and whole-genome sequencing confirmed that strain YMK25 is Klebsiella pneumoniae. Whole-genome analysis revealed a total genome length of 5,115,280 bp, a GC content of 57.61%, and it contained 4746 coding genes. Gene annotation results indicated genes involved in siderophore synthesis, phosphatase activity, and other plant growth-promoting functions, which align with the verified characteristics of strain YMK25. Furthermore, this strain exhibited significant metabolic capabilities. The pot experiment demonstrated that strain YMK25 promotes maize plant growth and assists in nutrient fixation in these plants. In conclusion, strain YMK25 is a high-quality PGPR with substantial potential for application in agricultural production, presenting promise for widespread use in sustainable agriculture. Full article

The high-elevation ecosystems of the Tibetan Plateau provide crucial ecosystem services including watershed protection and water provision for downstream human and wildlife communities. Thus, understanding the relationship between soil properties and vegetation under different management regimes is important as a warming climate alters these systems. This study assessed vegetation cover, quantified the distribution of soil nutrients, and examined the relationships among soil chemical properties and plant cover in the high-elevation shrublands (3300 to 3700 m) in the Qilian Mountains on the northeastern Tibetan Plateau of China. These vegetation surveys and soil sample collections were conducted on 15 shrubland plots at different soil depths and soil chemical properties were investigated at each elevation. The content of soil organic matter (SOM), total nitrogen (TN), available phosphorus (AP), and available potassium (AK) fluctuated along the elevational gradient, while soil pH was close to neutral (pH 7.4). At our sites, SOM and TN contents generally increased with elevation, and AK was positively correlated with Salix plant cover. Using PCA, we determined that PC1 captured 43% of the total variance, and SOM and TN were the top contributing features. As climate in the region warms and precipitation becomes more variable, understanding the current soil–vegetation equilibria and how vegetation may migrate in future years is important to predicting changes in this region, especially at high elevations. From a managerial perspective, our goal was to provide additional information for restoring and managing subalpine and alpine shrubland vegetation in the Qilian Mountains to ensure the future sustainable use of these systems. Full article

Bamboo forest density is a factor that critically impacts the growth of moso bamboo, soil quality, and productivity. In this study, four bamboo forest density treatment groups were established under a long-term bamboo-stocking retention model, namely 1200 ± 100, 1800 ± 100, 2400 ± 100, and 3000 ± 100 plants·hm⁻², while a traditional management model focused on selective logging, with a bamboo forest density of 2100 ± 100 plants·hm⁻² (CK), serving as the control group. The study aimed to investigate the impact of bamboo forest density on bamboo shoots, roots, and soil, identify key influencing factors, and determine the optimal management density for this management model. Under the novel management model, bamboo shoot yield and number exhibited a unimodal response to stand density. At a density of 2400 plants·hm⁻², the bamboo shoot yield reached its highest value of 18,822 kg·hm⁻², with 7080 shoots·hm⁻². Under the density of 2400 plants·hm⁻², the specific root length, specific root surface area and total nitrogen, phosphorus and potassium contents of 0–1 mm fine roots were higher, and the contents of soil organic matter, total nitrogen, available phosphorus and available potassium were also better. Correlation analysis showed that the bamboo shoot yield and the number of shoots were closely related to soil quality (water content, organic matter, total nitrogen, available phosphorus and available potassium), and the effect of root total nitrogen content on shoot yield was particularly significant (the explanation rate was 75.7%). The comprehensive growth status assessment (D3 > D4 > D2 > CK > D1) showed that there were differences in the performance of different density treatment groups. This information could help bamboo farmers improve yield while protecting soil quality. Full article

The effective removal of oxygen (O), nitrogen (N), sulfur (S), and oxide inclusions from superalloy reverts is crucial for enhancing service life and achieving cost efficiency. However, refining DZ125 superalloy presents particular challenges, as conventional processes prove ineffective against hafnium (Hf) oxides. This study introduces an innovative purification method combining droplet electron-beam melting (EBM) with centrifugal directional solidification. Through this advanced EBM technique, we successfully produced ultrapure DZ125 superalloy with nitrogen content reduced below 5 ppm and total O + N + S content below 10 ppm. Most significantly, the process nearly eliminated Hf oxides from the reverts, meeting the stringent purity standards for DZ125 superalloy. We conducted a comprehensive analysis of inclusion morphology and composition in three distinct regions: the top slag layer, final solidification zone, and interior section of the ingot processed at varying EBM power levels. Our findings reveal that MC-type carbides at the slag–crucible interface were formed. There are HfO₂, TaC, and Al₂O₃ in the final solidification zone, with notable encapsulation of HfO₂ particulates within Al₂O₃ particles; and few HfO₂ and Al₂O₃ inclusions exist in the ingot interior. It is also found that increasing EBM power from 36 kW to 46 kW significantly improved impurity removal efficiency, as evidenced by substantial reductions in both inclusion quantity and size. This enhanced purification stems from two primary mechanisms: (1) flotation of inclusions during EBM melting, facilitated by Marangoni convection, droplet stirring effects, and centrifugal forces generated by ingot rotation; and (2) decomposition of stable oxides enabled by the high-energy density characteristic of EBM and high-vacuum processing environment. This combined approach demonstrates superior capability in overcoming the limitations of traditional refining methods, particularly for challenging Hf oxide removal, while establishing an effective pathway for superalloy revert recycling. Full article

This study examines the particle size distribution (PSD) of calcareous soils under cultivated and natural conditions in Chenggong District of Kunming, Yunnan Province, China, using single-fractal and multifractal analyses. Soil samples were collected from the profiles of both land use types, and the PSD parameters, organic matter, and total nitrogen were determined. Single-fractal analysis showed that the single-fractal dimension (D) was mainly influenced by the clay content, with higher clay fractions corresponding to larger D values. The generalized dimension spectrum revealed clear differences between natural and cultivated soils: natural soils exhibited greater sensitivity to probability density weight index(q) changes and a more compact particle distribution, whereas cultivation led to broader PSD ranges and higher heterogeneity. The ratio D₁/D₀ was negatively correlated with the clay content, and multifractal spectrum asymmetry (Δf) indicated that fine particles dominate the variability in deeper layers. Compared with natural soils, cultivated soils had higher organic matter and total nitrogen, reflecting the influence of fertilization and tillage on the soil aggregation and PSD. These findings demonstrate that fractal theory provides a sensitive tool for characterizing soil structural complexity and land use impacts, offering a theoretical basis for soil quality assessment and the sustainable management of calcareous soils. Full article

Ultraviolet B (UV-B) radiation is a key environmental factor that limits plant growth and development. High UV-B intensity is a typical environmental feature in Turpan-Hami (Tuha) Basin in Xinjiang, China. In this study, the altitude-dependent UV-B adaptation strategies of plants in Tuha Basin were analyzed. Chlorophyll (Chl) and flavonoid (Fla) play an important role in absorbing UV-B radiation, scavenging free radicals, and maintaining photosynthetic performance under UV-B stress. Principal component analysis indicated that the total chlorophyll (Chl t), Chl a, Chl b, and Fla contents and the Chl a/Chl b ratio are important indicators for evaluating plant tolerance to UV-B. Noticeably, with increased altitudes, the roles of Chl b, Chl a/Chl b, and Fla become markedly significant. The characteristics of stomata, epidermal hair, and wax layer are closely correlated with the UV-B amount that reaches leaves. Epidermal hair density and cuticle thickness in leaves decreased with increased altitudes, whereas hydrogen oxide (H₂O₂) was significantly accumulated, but superoxide anion (O₂⁻) remained unchanged. High altitude significantly increased the stomatal apparatus area, density and specific leaf area. Moreover, plants without epidermal hair had a larger stomatal apparatus area compared with plants with epidermal hair. However, the presence or absence of epidermal hair had no effect on cuticle thickness, H₂O₂ and O₂⁻ levels. The carbon (C), nitrogen (N), and hydrogen (H) contents were high in plant leaves at high altitude, but the sulfur (S) content and C/N ratio were low. Taken together, plants in Tuha Basin could cope with UV-B radiation by synergistically regulating epidermal structures and synthesis of secondary metabolites. Meanwhile, these plants could further allocate and reconstruct organic elements to optimize their resource distribution in adaptation to UV-B radiation with different altitudes. Full article

Subsurface drip irrigation can improve crop water and fertilizer use efficiency, but it can cause soil hypoxia. We report on experiments performed in Aksu Prefecture, Xinjiang (41°17′ N latitude, 80°17′ E longitude), from April 2023 to October 2024 using oxygenated drip irrigation from the surface to 50 cm depth in an apple (Malus pumila Mill.) orchard, to examine the effects of drip irrigation on inter-root hypoxia, tree growth, fruit quality, and yield. Compared with surface oxygenated drip irrigation (CK), irrigating at 10 and 30 cm increased soil water content in the root system, elevated gibberellin, zeatin ribosides, and indoleacetic acid contents and reduced abscisic acid contents in new shoot tips. Compared with CK, branch and leaf nitrogen, phosphorus, and potassium contents were increased with irrigation at depths of 10 and 30 cm. The leaf nitrogen (N), phosphorus (P), and potassium (K) contents were increased by 18.03%, 22.42%, and 16.63%, respectively, in the treatment with a burial depth of 30 cm. Among treatments, irrigation at 30 cm produced the highest average daily plant water potential, and irrigation at 50 cm was the lowest. Maximum leaf soil–plant analysis development (SPAD) values occurred when irrigated at 30 cm, and minimum values occurred at 50 cm. For both years, the largest range of light flux utilization occurred when irrigated at 30 cm and the lowest when irrigated at 50 cm. Significant correlations between indoleacetic acid (IAA), total gibberellin (GA), zeatin riboside (ZRs), leaf N content, leaf K content, plant water potential (PWP), net photosynthetic rate (Pn), SPAD, and apple yield were determined by partial mantel analysis. A significant correlation was found between abscisic acid (ABA), IAA, GA, leaf P and K content, and apple quality. Principal component analysis revealed a burial depth of 30 cm had the highest principal component composite score, indicating that this burial depth, and oxygenation and fertilization regime most favored apple growth, yield, and quality. Full article