Abstract Aim and purpose The present work explores the isolated Magnetotactic bacteria and their magnetic nanoparticles for their biomedical application potential based on their magnetic properties. Findings MTB isolates were obtained from soils of dy lakebeds and different mineral rich mountains of Southern Karnataka, India and best two isolates were characterized by 16 S rDNA sequencing as Klebsiella species AK01 and Priestia species AK02 (NCBI GenBank (PP886460.1 and PP869085.1 respectively). The magnetosomes as nanoparticle packets were isolated and characterized by XRD, Sem-EDAX and FTIR analysis which confirmed complex of Fe and related metal magnetic materials in the system. The nanoparticles were functionalized by glutaraldehyde fixation of commercially available fungal alpha amylase and activity analysis procedures. The immobilization of enzymes was confirmed by FTIR stretches. Using 3D printer, Microfluidic cell mould was prepared which was used further for preparing basic microfluidic system consisting of 3% agarose and starch respectively. The magnetic actuation of microbial flow in the channels was recorded and images were taken. Conclusion The isolated MTB and magnetosome nanoparticles were characterized and latter were functionalized with enzyme and evaluated for actuation and external controls for potential biomedical applications. The potential application of MTB and their nanoparticles has immense potential in various microrobotic vistas of biotechnology and biomedicine. The present work enhances this repertoire of microbial application in bacteria hitherto not reported before.

ABSTRACT Soil organic carbon stocks (SOCS) play a critical role in mitigating atmospheric CO2 and enhancing ecosystem resilience, yet their controls in high-mountain environments remain insufficiently constrained. Using an integrated framework combining field sampling, remote sensing, machine learning, and multi-source environmental datasets, this study quantifies SOCS variability along elevation gradients across the climatically diverse region of Gilgit-Baltistan, northern Pakistan. Results reveal three dominant patterns. First, SOCS distribution is jointly regulated by elevation and climate, with humid mid-to-high altitudes functioning as net carbon sinks, whereas lower-elevation semi-humid and semi-arid regions exhibit persistent SOCS declines. This spatial–altitudinal coupling highlights the sensitivity of mountain SOCS to aridity across both vertical and horizontal landscapes. Second, climatic drivers exert contrasting effects: precipitation enhances SOCS accumulation in humid zones by promoting vegetation productivity, while rising temperatures in semi-humid and semi-arid belts accelerate carbon losses through enhanced decomposition. Third, vegetation–soil interactions amplify sequestration potential along elevation gradients. Grasslands developed on loamy soils at mid-to-high elevations store significantly higher SOCS than other land use–soil combinations, while carbon stocks decline sharply with soil depth, reflecting the vertical constraints imposed by shallow mountain soils. Together, these findings demonstrate that SOCS dynamics in fragile high-mountain ecosystems emerge from the interaction of elevation, climate variability, vegetation cover, and soil properties. Recognizing this multidimensional control is essential for designing zone-specific management strategies that enhance carbon sequestration, reduce vulnerability to climate change, and support regional contributions to global climate mitigation and sustainable development goals.

Apples in China are planted mainly in nutrient-poor mountain soil, and a large amount of fertilizer input results in resource waste and a decrease in nutrient utilization efficiency. Controlled-release fertilizer (CRF) has been shown to be environmentally friendly and increase crop yield, but nutrient release cannot be precisely synchronized with apple demand. Here, a suitable secondary fertilization method was established by a two-year apple field experiment with CRF and common compound fertilizer (CF) at various ratios under a 25% reduction in application. The application of CF and CRF changes the temporal and spatial distributions of soil NPK nutrients, decreasing NPK losses and NH3 emissions. The NH3 emissions under CF and CRF decreased by 17.98–44.86%, as N loss decreased by 11.59–29.81% and by 4.45–8.19%, with respect to those under CF alone, while the soil pH and electrical conductivity increased by 8.28–17.12% and 10.73–18.29%, compared with those under CF alone. The increase in soil P and K also decreased losses by 8.28–17.12% and 10.73–18.29%. The combined application of CF and CRF can increase soil microbial diversity and functional taxa and nutrient cycling genes, resulting in efficient nutrient transformation and supply for apple trees. The regulation of nutrients and microbes by the secondary application of CF and CRF drives an increase in apple yield of 23.71–54.32%, resulting in high economic benefits. In total, the application ratio of CF and CRF at 3:7 in March and July was an effective way to balance apple productivity and the soil ecological environment, providing a sustainable solution for mountainous orchard ecosystems globally.

Two novel bacterial strains designated CR2-8T and HWE2-09T were isolated from mountain soil and plant root, respectively, and characterized using a polyphasic taxonomic approach. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain CR2-8T shared the highest sequence similarity with Sphingobium limneticum 301T (98.0%), and HWE2-09T with Sphingobium rhizovicinum CC-FH12-1T (97.8%). The genome-based comparison indicated that both CR2-8T and HWE2-09T shared the highest relatedness with Sphingobium cupriresistens CU4T, sharing 84.05% and 84.7 % orthologous average nucleotide identity and 29.3% and 30.3 % digital DNA-DNA hybridization, respectively, all of which were clearly below the suggested cutoffs for species distinction. For both strains, the major fatty acids were two summed features, one consisting of C16 : 1 ω7c and/or C16 : 1 ω6c and the other consisting of C18 : 1 ω7c and/or C18 : 1 ω6c, and also C14 : 0 2OH and C16 : 0. The major ubiquinone was Q-10, and the main polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and phosphatidyldimethylethanolamine for both strains. The DNA G+C content of strain CR2-8T was 63.16 %, and that of strain HWE2-09T was 63.26 %. The phenotypic, chemotaxonomic and phylogenetic analyses indicate that each of the strains CR2-8T and HWE2-09T should be classified as a new species of Sphingobium, for which the names Sphingobium wonjuense sp. nov. (type strain=CR2-8T=KCTC 8939T=JCM 36935T) and Sphingobium erigeronicola sp. nov. (type strain=HWE2-09T=KCTC 8940T=JCM 36936T) are proposed.

The spatial distribution of risk elements and the impacts of acidification on mountain soils affected by anthropogenic emissions are poorly understood due to the limited number of corresponding case studies. This work examines the distribution of Ca, Mn, and Zn in topsoils of the mountain terrains of the Beskids along the eastern part of the Czech-Polish state border, which have been locally impacted by emissions of acid gases and dust from metallurgy in the 20th century. Samples of the top stratum of mineral soil horizons, rock fragments, and birch leaves were collected from 140 sites within an approximately 12 x 12 km area in mountain ridges and slopes, primarily covered by forests. Concentrations of Mn and Zn in soils and leaves were subjected to interelement correlations and spatial distribution analyses. Soil Mn and Zn concentrations were corrected using Fe as a lithogenic reference element to correct a part of natural geochemical variability of the bedrock. While topsoil Mn and Zn concentrations directly reflect contamination, the uptake of Mn and Zn by birch was also enhanced by low soil Ca levels. The probabilistic nature of the factors controlling soil contamination and the topographically-driven distribution of emission loads necessitate the use of less conventional data-mining tools. The variable probability that emission contamination has been really recorded in individual environmental samples requires the application of robust regression, quantile statistics, and/or rational data post-stratification. Visual examination of geochemical maps with quantile-classified layers and geographically weighted regression (GWR) proves advantageous in data mining, because conventional hotspot analysis using geostatistics is weakened by considerable spatial noise. Point contamination of the Beskid soils is maximal on slopes exposed to Třinec at a distance of approximately 15 km and at elevations between 600 and 700 m a.s.l. The spatial heterogeneity of soil Mn and Zn concentrations arises from uneven emission scavenging depending on landscape topography, horizontal emission deposition, and the translocation of Ca and Mn ions downslopes.

Analysis of cadmium sources in surface soil in typical karst regions: Anthropogenic input contribution and atmospheric transport impact.

In nutrient-limited high-elevation ecosystems, plants rely on arbuscular mycorrhizal (AM) fungi to provide mineral phosphorus (P) in the form of phosphate (PO43-). AM fungi gather these nutrients from phosphorus-cycling bacteria (PCBs) that can mineralize PO43- from organic matter and solubilize mineral-bound P. How climate, soil factors, and nutrient limitation influence AM fungi and PCB assembly remains unclear. We collected soil from montane meadows across a 1,000-m elevation gradient on three replicate mountainsides and analyzed AM fungal marker genes, P-cycling genes from shotgun metagenomes, and edaphic measurements. High-elevation soils had nearly 50-fold less soil PO₄³⁻ and 60% more AM fungal hyphae than low-elevation soils. AM fungal turnover was linked to changes in pH, organic carbon, and PO₄³-. The composition of 198 P-cycling genes was influenced by the AM fungal community structure. Drivers of individual PCB functional genes, including pH and organic carbon, varied with gene phylogeny. We found a trade-off in P-cycling strategies across elevation: P-rich, low-elevation soils supported root-colonizing AM fungi and organic P-mineralizing bacteria. P-poor, high-elevation soils were dominated by stress-tolerant AM fungi and mineral P-solubilizing bacteria. Our results suggest that AM fungi and PCB community turnover across elevation are both shaped by pH, organic carbon, and P availability. With continued climate warming, the structure and function of mountaintop ecosystems might shift to resemble lower elevations, disrupting long-established and specialized microbial assemblages, with consequences for P-cycling dynamics and the total P available to plant communities.IMPORTANCEPhosphorus (P) limits plant productivity in high-elevation ecosystems, yet the microbial networks that mobilize P, including arbuscular mycorrhizal (AM) fungi and phosphorus-cycling bacteria (PCBs), remain under-characterized in these nutrient-poor soils. We show that across a 10,00-m elevation gradient, AM fungi and P-cycling gene assemblages shift predictably with pH, organic carbon, and phosphate availability. Higher elevations, with less available P, select for stress-tolerant AM fungal taxa and PCB strategies geared toward mineral solubilization, while low-elevation sites favor root colonization by AM fungi and organic P mineralization. These results suggest that nutrient limitation can constrain microbial community assembly in consistent ways across landscapes. High mountain soils are low in P and rely on a network of underground AM fungi and PCB to deliver nutrients to plants. This study shows how those underground relationships reorganize with elevation and how climate change could collapse long-standing microbial strategies by pushing high-elevation ecosystems toward lowland conditions. As soils warm and dry, the microbial scaffolding that supports alpine plant life may become increasingly unstable.

This study provides the first integrated characterization of soils associated with natural populations of Capparis herbacea Willd. in southern Kazakhstan. Field surveys and soil sampling were conducted in June-July 2023 across three contrasting sites: (Population 1, Sogeti Gorge), piedmont plain (Population 2, Merki), and semi-arid lowland (Population 3, Saryagash) environments. Standard profile descriptions and laboratory analyses followed national GOST and classical pedological methods. Across sites, soils were alkaline (pH 7.8-8.9) and carbonate-rich, with low humus (0.18-6.3%). Texture ranged from light loam (P1) to medium loam (P2) and sandy loam (P3); moisture distribution varied from higher values in mountain soils (up to 21.6%) to more uneven patterns in semi-arid lowlands (6.5-20.7%). Available macronutrients were generally limited: P2 showed near-absent phosphorus, while P3 had relatively higher potassium. Salinity contrasted sharply: P1-P2 non-saline (total salts ~0.037-0.062%), whereas P3 exhibited moderate to strong salinity (0.082-0.910%), with upper horizons moderately saline and deeper horizons strongly saline, dominated by sulfates and calcium ions. These findings represent the first base-line data on soils supporting Capparis herbacea Willd. in southern Kazakhstan. Capparis herbacea Willd. demonstrates strong ecological plasticity, tolerating both carbonate non-saline and sulfate-enriched saline soils. Its adaptability highlights potential for use as a soil quality indicator and in restoration of degraded lands in Central Asia.

Mineralogical drivers of fertility and pedogenetic processes in tropical mountain soils of southeastern Brazil

Abstract The knowledge of the influence of environmental factors on soil properties and spatial distribution of soil organic carbon (SOC) and soil particle size fractions is crucial to soil management and sustainable productivity. SOC provides an insight about soil capacity to perform ecosystem services while soil particle size fractions influence several key soil characteristics. This study assessed the impacts of environmental elements on spatial changes in SOC and sand, silt and clay using random forest (RF), regression kriging (RK), cubist regression (CR), multiple linear regression (MLR) and ordinary kriging (OK) models. Sixty (60) composite soil samples were obtained at 0-30 cm depth and distance of 200-500 m apart, and analyzed for physicochemical properties. The digital elevation model (DEM) of the area was acquired at the spatial resolution of 30 m from USGS and processed. The models were evaluated using bias, coefficient of determination (R2), correlation concordance coefficient (CCC), mean square error (MSE) and root mean square error (RMSE). The soil had sandy clay loam, sandy loam and loam texture with strongly acidic pH (pH <5.5) and high OC (2%). Available P and exchangeable cations were all low while cation exchange capacity and base saturation were high. Soil pH> SAVI (soil adjusted vegetation index)> NDVI (normalized difference vegetative index) > rainfall were found to be the top four environmental variables influencing OC prediction while temperature and slope had the least effect. Again, MLR model better predicted OC (R2 of 0.324, CCC of 0.537, MSE of 0.585, RMSE of 0.764), OK better predicted clay (MSE=2.680, RMSE=3.490), CK in sand (MSE = 7.434, RMSE =5.568). Also, MLR, CK and OK proved to have the best capacity in prediction SOC and sand, silt and clay in mountainous soils. The findings could therefore could be used by policy makers and planners as tools for decision making on sustainable soil and environmental management alternatives and precision agriculture.

The areal representativeness in the state system of specially protected natural areas (SPNA) (nature reserves, national parks and wildlife sanctuaries) of the soil cover of large regions with similar natural conditions—plain and mountain soil provinces of the Soil-Ecological Zoning (SEZ) Map of the Russian Federation of scale 1:8 000 000—was assessed by the method of geoinformation analysis. The highest representation of soil cover in SPNA areas was found for the Eurasian polar soil-bioclimatic region, the lowest—for the Central deciduous-forest, forest-steppe and steppe soil-bioclimatic region. It has been shown that out of 101 SEZ’ provinces 14 (11 plain and 3 mountain) haven’t specially protected natural areas. On average, 3.4 % of the soil provinces’ area in Russia is protected in SPNA, mountain provinces are 2 times more provided with territorial nature protection compared to plain ones. A detailed analysis of the typological representativeness of the protected area system in relation to main soils of soils’ provinces was conducted using the example of the plain provinces of the Central deciduous-forest, forest-steppe and steppe soil-bioclimatic region. It is shown that at present 7 soils—legend units of the Soil Map of Russia of scale 1:2 500 000—which predominate in area in 9 plain SEZ’ provinces, are not provided with territorial protection. In total, they occupy 229.3 thous km2 in Russia. The most significant areas of these soils are located in the Ciscaucasia and in the south of Western Siberia. Most of these territories have been changed by economic activity, the need for additional environmental and soil monitoring sites is high, and the possibilities of their organization are small. In order to ensure territorial protection of the last fragments of provinces’ main soils with natural complexes and to create ecological monitoring sites there, it is necessary to survey the soil cover of regional protected areas and consider the possibilities of increasing the protection level for the most representative areas. In order to ensure territorial protection of the last fragments of provinces’ main soils with natural complexes and to organize ecological monitoring sites there, it is necessary to survey the soil cover of regional protected areas and consider the possibilities of increasing the protection level for the most representative areas.

Antibiotic resistance is a global health crisis, but environmental pathways of resistance dissemination to farm workers remain poorly understood. Agricultural soils represent critical but underexplored reservoirs of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs), particularly in orchards where antibiotics such as streptomycin and oxytetracycline are widely used for fire blight control. Here, we conducted a nationwide investigation of orchard soils in South Korea, integrating high-throughput qPCR, 16S rRNA gene sequencing, and quantitative microbial risk assessment (QMRA). We detected 297 ARGs and 52 MGEs, with eight core genes [aac(3)-VIa, tetL, aadE, sul1, qacH_351, tnpA-1, IS6100, and intI1] significantly enriched in orchard soils but absent in non-orchard soils, such as national parks or mountain soils. Aminoglycoside- and tetracycline-resistance genes were dominant, directly reflecting the application of streptomycin and oxytetracycline. QMRA estimated that orchard farmers ingest resistance genes through soil contact, with aac(3)-VIa posing the highest risk (~29 ingestion events per farmer annually), followed by qacH_351, tetL, and tnpA-1. These results demonstrate the quantifiable occupational risks of ARG exposure in orchard environments. By combining resistome profiling, microbial networks, and QMRA, this study establishes a framework for assessing the public health implications. Although the ingestion of ARGs may not immediately cause impacts on human health, such exposure has the potential to enrich antibiotic resistance within the gut microbiome of farm workers, thereby increasing the probability of treatment complications if infections occur.IMPORTANCEAntibiotic resistance is widely recognized as one of the most concerning threats to public health, yet the pathways through which resistance emerges and spreads remain underexplored. Orchard soils, where antibiotics are sprayed to control plant diseases, represent an overlooked environment where resistance may develop and circulate to people who work the land. By examining soils from orchards at a nationwide scale, we found resistance genes that mirror the antibiotics used in these settings and showed that farm workers are regularly exposed to them through routine contact with soil. This study provides the direct evidence that orchard farming can contribute to human exposure to resistance, heralding the need to include agricultural environments in efforts to prevent the spread of resistance. Our work offers a way to measure these risks and can guide protective strategies for workers and communities.

Microplastic pollution in Morocco's High Atlas: First evidence and selective impact on soil microbiome across an elevational gradient.

This study evaluated an innovative protocol for the accelerated vegetative propagation of Euphorbia antisyphilitica (candelilla), an endemic shrub threatened by unsustainable harvesting in Mexico’s arid regions. Three propagation systems were compared, combining hydroponics, nursery, and open-field approaches with natural biostimulants and conventional rooting agents. Hydroponics with a natural biostimulant blend of Rosmarinus officinalis, Lens culinaris and Cinnamomum zeylanicum extracts yielded the fastest and most vigorous rooting, achieving functional root systems within four weeks, a reduction of over 90% compared to traditional timelines. Survival exceeded 99%, demonstrating the reliability of this approach. In contrast, indolebutyric acid proved ineffective in hydroponics due to its instability in aqueous media. Nursery propagation highlighted the importance of substrate selection, with native mountain soil outperforming commercial and agricultural substrates, likely due to its favorable pH and natural mycorrhizal associations. Overall, the integration of hydroponics and natural biostimulants provided the most sustainable and reproducible protocol, offering significant advantages for ecological restoration, ex situ conservation, and community-based management of arid ecosystems. These results establish a scientific foundation for scaling up vegetative propagation of candelilla and similar species, reducing dependence on wild populations while promoting restoration in degraded arid landscapes.

Elevational control on microbial residues contributions to soil organic carbon: Dual regulation by soil moisture and total nitrogen dynamics in semi-arid mountain soils

Abstract Monitoring of soil organic carbon (SOC) is a part of the Partial Monitoring system – Soil (ČM S-P). ČM S-P consists of two subsystems. One of them is a subsystem of the key monitoring sites (16) in sampling repetition every year. The key monitoring localities cover all soil types, soil use (cropland, grassland) and a wide range of altitudes (111 – 975 m). In 16 key monitoring localities the content of SOC in topsoil is measured every year. This article shows the development of SOC content for a 30-year period on all key monitoring sites, separately on cropland, grassland and sites with land use changes, in lowland (< 300 m) and mountain soils (> 300 m). The 30-year monitoring period was divided into three time periods. On all key monitoring localities, separately on grassland and cropland and on lowland and mountain soils, the lowest median SOC content in the first time period was found. The reason could be substantial changes in Slovakia´s agriculture, mainly a sharp drop in organic fertiliser consumption on 90-ties. Between the first and second time period, SOC content is statistically significantly increased. We assume that it was caused by the state subsidy policy to increase the content of organic matter in the soil. Between the second and the third time period, changes of SOC content were negligible. Our results also show that the main driving forces affecting SOC content are altitude (statistically significantly higher SOC content on mountain soils compared to lowland), land use and land use changes (statistically significant higher SOC content on grassland compared to cropland).

Historical and future dynamics of soil organic carbon and driving mechanisms in mountainous soils of China

ABSTRACT Ecological security serves as a critical metric for assessing regional sustainable development. Climate change and human activities have intensified the deterioration of global ecosystems, which cause deterioration of ecosystem health and land degradation, and threaten ecological security. Consequently, this study addresses land degradation and ecosystem health by employing the United Nations Land Degradation Neutrality (LDN) assessment framework and the Vigor‐Organization‐Resilience‐Service (VORS) model. It visualizes the states of land degradation and ecosystem health from qualitative and quantitative perspectives. Based on the four‐quadrant model, the study investigates the ecological security zoning of the mountainous soil conservation area in southern Jiangxi Province from 2006 to 2022. The results of the study are as follows, (1) land productivity degradation was the dominant factor of land degradation in the study area, while soil organic carbon improvement was the dominant factor of land improvement; (2) The research area exhibited a net gain in land improvement compared with degradation, achieving the goal of LDN advocated by the United Nations, from 2006 to 2022; (3) the area of diseased, sub‐healthy and healthy ecosystems increased by 1.01%, 49.88%, and 1.56%, respectively, and the area of sickness and fragile healthy areas decreased by 2.44% and 49.92%, respectively, from 2006 to 2022; (4) the areas of insecure area and lowly secure area decreased by 6.54% and 42.93%; the areas of moderately secure and secure area increased by 2.25% and 31.15%, from 2006 to 2022. Based on the research results, it is recommended that each administrative region should formulate soil conservation plans according to local conditions, especially by focusing on curbing land degradation and ecosystem deterioration to enhance the regional ecological security. The findings can provide references for controlling soil erosion and improving ecosystem quality in the study area, as well as offer insights into ecological zoning management and restoration in the region.

• Analysis of SOC stocks and stability across 170 soil pits in the Western Alps, encompassing diverse elevations, climates, and lithological contexts. • SOC characterization based on mid-infrared spectroscopy and Rock-Eval® thermal analyses. • Conventional methods overestimate SOC stocks in mountain regions by up to twofold, primarily due to neglecting high coarse fragment content. • SOC stabilization shifts from organo-mineral interactions in developed lowland soils to climate-driven stabilization in less developed highland soils. • SOC stocks at the subalpine-alpine boundary are particularly vulnerable to climate change impacts. Estimating SOC stocks and stability, as well as modeling their response to rising temperatures, is crucial for predicting climate change impacts. This is particularly true in mountainous regions, where low temperatures slow down SOC decomposition, resulting in higher SOC stocks compared to soils at lower elevations. However, these stocks are also more vulnerable to warming, increasing the risk of SOC depletion. Such conditions create the potential for a positive feedback loop in which warming accelerates SOC losses, further amplifying climate change impacts on these sensitive ecosystems. To better understand the factors controlling SOC stocks and stability in mountain soils, we sampled 170 soil profiles along 29 elevation gradients in the western Alps from 280 to 3160 m a.s.l. We assessed SOC stocks and chemical composition using mid-infrared spectroscopy method and SOC stability with Rock-Eval® thermal analysis. Our findings, based on an unprecedented dataset, reveal a clear elevational pattern in SOC properties. SOC stocks increase with elevation up to the montane belt (1200–1500 m a.s.l.), remain relatively stable through the subalpine zone, and then decline beyond the subalpine/alpine boundary (2200–2400 m a.s.l.). Notably, this transition is also marked by a significant drop in SOC stability, suggesting a shift in the dominant stabilization processes at higher elevations. Our results also indicate that SOC stocks and stability are influenced by a complex interplay of factors. At higher elevations, climate emerges to be the dominant factor, whereas lithology and weathering play a more significant role at lower elevations. These results suggest that at high-elevations, harsh climatic conditions favor stabilization of SOC, while less developed soils limit organo-mineral interactions. In contrast, at warmer, lower elevations with higher carbon fluxes, more developed soils facilitate organo-mineral interactions, thereby enhancing SOC stability in the long term. Consequently, alpine grasslands, which contain substantial stocks of labile carbon stabilized by climatic conditions, appear to be particularly vulnerable to the effects of climate warming.

Mountain-soil microaggregates play a crucial role in carbon storage and the transport of heavy metals. However, their biogeochemical behavior along elevation gradients is not well understood. In this study, we examine the chemistry of microaggregates from 200 m to 1,140 m on Tongbai Mountain, located in Central China. We employ a range of surface- and bulk-sensitive techniques, including X-ray photoelectron spectroscopy, scanning electron microscopy with energy-dispersive spectroscopy, X-ray fluorescence, Fourier-transform infrared spectroscopy, and X-ray diffraction. Our analysis reveals three distinct altitudinal regimes in elemental distribution. At low elevations (<600 m), microaggregate surfaces are enriched in Mn and Fe (XPS Mn up to 1.61% and Fe ≈ 3.37% at 200 m), reflecting exogenous inputs and reducing conditions that favour metal mobility. Mid-elevations soils (600–700 m) host elevated P and Al, signalling intense weathering and biological turnover in this transition zone. Above 700 m, cooler and wetter conditions promote the formation of organo-mineral complexes that sequester C, N and Fe; the C-N component in XPS spectra rises from 19.2% at 200 m to 26.4% at 1,140 m, while pyridinic-N increases from 21.1% to 44.4%. Concurrently, Fe3+ becomes the dominant iron species, consistent with enhanced humification and oxidative weathering at higher elevations. These trends point to an altitudinal threshold near 600–700 m. Below this break point, weaker organo-mineral associations allow greater heavy-metal mobility and carbon loss. Above it, robust complexes act as sinks for both carbon and metals, buffering soils against disturbance. Management should therefore be stratified: stringent pollution controls at low elevations, vegetation reinforcement on mid-slopes and conservation of high-elevation refugia. Our findings provide a mechanistic framework for mountain soil stewardship under global change. Projected warming and altered precipitation are likely to intensify metal leaching at lower elevations while underscoring the role of high-elevation soils as critical reservoirs for carbon and metal retention within China’s north–south climatic transition zone.