Table of Content

10 August 2026, Volume 45 Issue 8

Previous Issue   

Species composition and spatial distribution of global lanternfish.

DIAO Qingqing, CHEN Zuozhi, TIAN Han, JIANG Yan’e, ZHANG Jun

2026, 45(8):  2465-2475.  doi:10.13292/j.1000-4890.202608.001

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Lanternfish are vital to the deep-sea ecosystems, with considerable economic potential. We review the research progress on species diversity of lanternfish, the effects of seamounts and ocean currents on their species composition and distribution, as well as the diel vertical migration of lanternfish. To date, 256 species of lanternfish have been documented globally, classified into 2 families (Myctophidae and Neoscopelidae) and 37 genera. Among these, the Myctophidae comprises 34 genera and 250 species, with genus Diaphus (79 species) exhibiting the highest species richness. From the perspective of species diversity, the Pacific Ocean hosts the greatest number of lanternfish species (177), followed by the Indian Ocean (117), the Atlantic Ocean (89), and the Southern Ocean (11). Notably, the South China Sea and the East China Sea host 81 and 15 species of lanternfish, respectively. Seamounts increase the complexity of marine habitats, significantly influencing the spatial distribution and species diversity of lanternfish, and regulating their distribution by limiting the vertical migration depth and altering food supply. The structural complexity of ocean current zones, geographical latitude, and primary productivity levels collectively shape the diversity patterns of lanternfish. Upwelling boosts productivity, drawing lanternfish to aggregate, while fronts and topographic barriers shape their regional distribution. Species diversity of lanternfish peaks in tropical-subtropical seas (e.g., the Australian Current Zone), with regional differentiation driven by currents such as the Kuroshio and South Equatorial Counter Currents. Lanternfish are highly sensitive to mesoscale oceanic structures in their diel stratification behavior, with interspecific differences and regional heterogeneity in their response modes. Controlling factors include photoperiod, prey distribution, and ocean currents. This article would help enhance understanding of lanternfish and their roles in the deep-sea ecosystem and thus provide scientific support for their resource utilization.



Environmental drivers of glass eel (Anguilla japonica) recruitment in the north coastal waters of the Yangtze River Estuary.

ZHANG Chengbin, SONG Dade, LI Guodong, TIAN Tuo, LIU Qiang, WANG Shuyan, LIANG Long, LI Jiayang, XIONG Ying

2026, 45(8):  2476-2484.  doi:10.13292/j.1000-4890.202608.012

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To identify the key environmental drivers of glass eel (Anguilla japonica) recruitment in the north coast of the Yangtze River Estuary, we developed a generalized additive model (GAM) using fishing log data from 21 selected commercial vessels during the licensed fishing seasons (2022-2024) and ten synchronized environmental variables. The results revealed a significant temporal decline in glass eel resources over the three years, with a progressive delay in the timing of peak catches. In the optimal GAM, sea surface salinity, dissolved inorganic phosphorus (DIP), and dissolved inorganic nitrogen (DIN) were the key environmental factors influencing glass eel recruitment, with explanatory contributions of 17.0%, 15.1%, and 13.0%, respectively. DIP showed an oscillating rise with rapid (0.13-0.17 mmol·m^-3), slow (0.17-0.25 mmol·m^-3), and stable (>0.25 mmol·m^-3) phases. DIN exhibited bimodal oscillations, decreasing (5-6 mmol·m^-3), increasing (6-18 mmol·m^-3), and then sharply declining (18-20 mmol·m^-3). Our results indicated that nutrients (DIP and DIN) and sea surface salinity are key environmental drivers influencing glass eel recruitment in the north coast of the Yangtze River Estuary. These findings elevate the role of nutrients from ambiguous background factors to critical determinants of recruitment dynamics, offering a novel perspective for understanding fluctuations in glass eel resources. This new perspective provides a crucial theoretical foundation for the scientific management of glass eel resources.





Dietary structure and the individual and regional differences of Leiocassis longirostris in the Yangtze River Estuary.

TANG Zeping, SHU Chuanjun, YANG Gang, GENG Zhi, ZHAO Feng, ZHANG Tao, LI Shan

2026, 45(8):  2485-2493.  doi:10.13292/j.1000-4890.202608.002

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The Yangtze Estuary is one of the most important fishing grounds in China, providing favorable ecological conditions for the survival and reproduction of numerous aquatic organisms. Following the implementation of the Yangtze River fishing ban, populations of economically valuable species such as Leiocassis longirostris have begun to recover. In this study, L. longirostris specimens were collected in May 2024 from the Yangtze River Estuary. Stomach content microscopic examinations were conducted to analyze dietary composition and spatial variation. A total of 25 prey taxa were identified, dominated by crustaceans, with the zoeae of the Chinese mitten crab (Eriocheir sinensis) overwhelmingly predominant. Diet composition varied across size classes. Juveniles primarily consumed water fleas and E. sinensis zoeae. Subadults mainly fed on E. sinensis zoeae with some individuals beginning to prey on fish, while adults exhibited signs of cannibalism. There was distinct spatial heterogeneity in prey composition among sampling stations, largely influenced by benthic resource distribution and environmental factors. The diversified dietary structure of L. longirostris reflects its strong adaptability to environmental changes, and crustacean resources—especially E. sinensis—showed substantial recovery following the fishing ban. These findings provide essential baseline data and scientific insights for fisheries resource conservation and ecological management in the Yangtze River Estuary.





Fish community structure and environmental drivers in the National Aquatic Germplasm Resources Reserve for Cyprinus carpio and Leiocassis longirostris in the Huaihe River.

ZHOU Yanfeng, ZHANG Huimin, CHEN Yongjin, YU Zhenfei, SUN Qihao, XU Dongpo

2026, 45(8):  2494-2503.  doi:10.13292/j.1000-4890.202608.003

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To clarify the status of fishery resources and the relationships between fish community structure, biodiversity, and environmental factors, we conducted a consecutive five-year (2019-2023) field monitoring in the National Aquatic Germplasm Reserve of Cyprinus carpio and Leiocassis longirostris (Jintu Gorge, Huaihe River). We analyzed the spatiotemporal differentiations of fish community and identified the key driving environmental factors. The results showed that a total of 52 fish species were recorded, belonging to 5 orders, 11 families, and 38 genera. Cypriniformes was the dominant group, accounting for 67.38% of the total species, with obvious interannual variations in dominant species. The Shannon diversity index, Pielou evenness index, Margalef richness index, and Simpson dominance index showed significant temporal differences but spatial convergence, and the overall biodiversity was at a medium level in the Huaihe River Basin. The abundance-biomass comparison (ABC) curve analysis indicated that fish community was unstable from 2019 to 2020 and tended to stabilize during 2021-2023. Redundancy analysis (RDA) revealed that transparency, total nitrogen, and dissolved oxygen were the dominant environmental factors affecting fish community structure, followed by water temperature, ammonium nitrogen, and dissolved total phosphorus.





Seasonal differences of assembly mechanism for zooplankton community in Luoma Lake.

CHEN Kang, JIANG Wanxiang, WU Dayong, CHEN Xinlei, HAN Jiamin, QIN Haiming, CHEN Jing

2026, 45(8):  2504-2514.  doi:10.13292/j.1000-4890.202608.008

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The metacommunity model is an effective approach for characterizing the mechanisms in structuring zooplankton community, and a key method for analyzing the process of environmental filtering and spatial diffusion limiting of zooplankton community. To elucidate the processes underlying zooplankton community assembly and to explore seasonal variations in the driving mechanism, a survey across different seasons was conducted at 20 sampling sites in Luoma Lake. A total of 98 zooplankton species, belonging to 23 families and 54 genera, were recorded. The average zooplankton density was 99.5±14.2 ind·L^-1, and the average biomass was 0.837±0.094 mg·L^-1. Dominant species included Brachionus calyciflorus, Asplanchna priodonta, Microcyclops varicans, Mesocyclops leuckarti, Ceriodaphnia quadrangular, and Bosmina longirostris. The structure and diversity of zooplankton communities showed significant seasonal variation (P<0.01). Environmental filtering and dispersal limiting had different effects on community structure of zooplankton across seasons. In spring, autumn, and winter, environmental filtering and spatial diffusion limiting jointly shaped the zooplankton community structure, driven primarily by dissolved oxygen, phosphate, chemical oxygen demand and medium-scale spatial factors (PCNM2, PCNM3, PCNM5, PCNM7, and PCNM8). In summer, however, environmental filtering played a more dominant role, mainly associated with total nitrogen, nitrate, and medium-to-large scale spatial factors (PCNM3 and PCNM5). Overall, environmental filtering plays a leading role in zooplankton community assembly.





Photosynthetic physiological response of Sargassum horneri to the combined effect of light intensity and inorganic phosphorus.

GUO Xiaoxi, XU Zhiguang, LIU Ting, BAO Menglin, YAN Fang

2026, 45(8):  2515-2521.  doi:10.13292/j.1000-4890.202608.005

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The frequent occurrence of golden tides caused by Sargassum horneri in China’s coastal areas has brought negative impacts on the nearshore ecosystems and coastal economy. Eutrophication of seawater is considered an important inducement for the formation of golden tides. Focusing on two environmental factors (light intensity and inorganic phosphorus concentration) during golden tide outbreaks, we set three light intensities (LL, 10; ML, 60; and HL, 150 μmol photons·m^-2·s^-1) and two inorganic phosphorus concentrations (LP, 0.5 and HP, 50 μmol·L^-1), to explore their combined effects on photosynthetic physiology of S. horneri. The results showed that under low and medium light conditions, high phosphorus concentration did not affect the relative growth rate (RGR) and photosynthesis of S. horneri. Under high light conditions, the RGR of S. horneri in high phosphorus level reached a maximum of 3.51%·d^-1, which was 53.87% higher than that in low phosphorus level. High phosphorus level significantly increased the maximum net photosynthetic rate (P_max), dark respiration rate (R_d), and photosynthetic utilization efficiency (α) at high light level, with the P_max reaching 57.42±6.21 μmol O₂·h^-1·g^-1 FW. Compared with LL+HP and HL+LP treatments, LL+LP treatment promoted the accumulation of chlorophyll c content in S. horneri by 72.12% and 63.87% , respectively. High light intensity promoted the synthesis of soluble protein but reduced the content of soluble carbohydrate, which was not affected by phosphorus concentration. High phosphorus level significantly enhanced phosphorus absorption rate, and reached the highest value (0.254 μmol·d^-1·g^-1 FW) under low light conditions. Photosynthesis and growth rate of S. horneri significantly increased with increasing light intensity, but high phosphorus level significantly promoted photosynthesis and growth of S. horneri under high light conditions. It is speculated that the combination of eutrophic, highphosphorus seawater and high surface light environments may lead to rapid growth of S. horneri, thereby promoting the occurrence of golden tides and accelerating their development.





The impact of herbivorous soil animals on fine root production of typical forests in eastern China.

QIU Yetong, LONG Fuqiang, ZHANG Qixuan, ZHENG Jingxi, WANG Xiuwei, SUN Tao

2026, 45(8):  2522-2530.  doi:10.13292/j.1000-4890.202608.029

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As a key component of carbon cycling in terrestrial ecosystems, the production of fine roots is regulated by both environmental and biological factors. Herbivorous soil animals are an important factor influencing fine root turnover. To elucidate the mechanisms by which herbivorous soil animals influence fine root production across broad geographical gradients, we established 17 plots in natural secondary forests spanning a latitudinal range of 18°36′N-53°26′N in eastern China. We manipulated herbivorous soil animal activity by applying insecticides to control their feeding on roots. Following one-year treatment, fine roots were collected from the 0-20 cm soil layer, classified using the root order classification approach, and their production was quantified to examine differential responses of absorptive fine root (AFR) and transport fine root (TFR) yields to herbivory disturbance. The results showed that: (1) under natural conditions, both AFR and TFR production exhibited a significant increasing trend from north to south sites, with yields in tropical and subtropical regions being significantly higher than those in temperate and cold-temperate regions. Specifically, AFR production in tropical forests was 1.5-2.1 times of that in cold-temperate plots (78-94 g·m^-2), and TFR production was 3-4 times of that in cold-temperate plots (138-150 g·m^-2). Some mid-subtropical plots had lower yields than adjacent areas in the same climatic zone due to micro-environmental differences. (2) After excluding herbivorous soil animals, AFR and TFR production significantly increased  in half of the plots, but the magnitude of response differed significantly across latitude zones. AFR production increased by 20%-25% and TFR production by 25%-30% in low-latitude tropical and subtropical regions, with AFR yields in some subtropical plots being the highest among adjacent latitudes after treatment. AFR production increased by only 10%-15% in high-latitude cold-temperate to temperate regions, with cold-temperate plots becoming low-yield areas and showing no significant geographical gradient. Two-way ANOVA Showed that there was a significant interaction between treatment effects and latitude zones (P<0.05), with a stronger regulatory effect of soil animals on fine root production in low-latitude regions. (3) Fine root production was highly significantly negatively correlated with latitude and significantly positively correlated with mean annual temperature and annual precipitation, confirming that hydrothermal condition is the fundamental driver of geographical differentiation of fine root production. The regulatory effect of herbivorous soil animals showed latitudinal dependency. Low-latitude regions induced plant compensatory growth through feeding pressure, while high-latitude low-temperature environments inhibited soil animal activity, masking their effects by climatic factors. This study provides an important reference for further exploring the relationship between herbivorous soil animals and fine root production in forests, and has important theoretical significance for understanding the relationship between energy flow and material cycling in forest ecosystems.





Altitudinal variations in fine-root traits of different root branch orders of Picea schrenkiana in the Tianshan Mountains.

ZHAO Rui, CHANG Shunli, HE Ailin, SUN Xuejiao, ZHANG Yutao

2026, 45(8):  2531-2540.  doi:10.13292/j.1000-4890.202608.021

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Fine-root morphological and stoichiometric traits are key regulators of plant nutrient use strategies. However, altitudinal variations in these traits and their trade-offs in Picea schrenkiana remain poorly documented. In this study, fine-root samples of P. schrenkiana were collected by excavation at four altitudes (1800, 2100, 2400, and 2700 m) in the Tianshan Mountains. Morphological and stoichiometric traits of different root orders were measured. We investigated the variations in root diameter (RD), specific root length (SRL), specific root area (SRA), root tissue density (RTD), and carbon (C), nitrogen (N), and phosphorus (P) concentrations and ratios (C∶N, C∶P, N∶P) of different root orders across altitude levels to elucidate the resource acquisition strategies. The results showed that: (1) Altitude and root order significantly influenced the morphological traits of fine roots (P<0.01). RD and SRL of the same root order generally increased with altitude, whereas SRA and RTD exhibited a unimodal pattern, peaking at mid-altitudes. At a given altitude, RD and RTD increased with increasing root order, while SRL and SRA decreased. (2) Altitude and root order significantly affected fine-root C, N, and P concentrations and ratios (P<0.01). With increasing altitude, C content in absorptive roots (orders 1-3) increased, while that in transport roots (orders 4-5) remained stable. The N content and N∶P ratio in both root functional categories followed a unimodal pattern, contrasting with the trend of C∶N ratio. The P content increased with altitude, whereas C∶P ratio decreased. Absorptive roots generally had higher N and P contents but lower C content, C∶N, and C∶P than transport roots. (3) Functional traits of P. schrenkiana fine roots revealed two primary dimensions of ecological strategy variation across altitudes: “do-it-yourself versus outsourcing” and “resource acquisition versus conservation”, with distinct strategic preferences at different altitudes.





Temporal variations of soil greenhouse gas fluxes and their responses to freeze-thaw cycles in a broadleaved Korean pine forest of Changbai Mountain.

SHI Qingxian, GUO Chuying, ZHANG Leiming

2026, 45(8):  2541-2552.  doi:10.13292/j.1000-4890.202608.027

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Soil greenhouse gas emissions are a critical component in assessing the function of ecosystems as carbon sources and sinks. Soil freeze-thaw cycles influence these emissions by altering soil carbon (C) and nitrogen (N) cycling. However, there remains a limited understanding about the temporal variations in soil greenhouse gas fluxes during freeze-thaw periods and the regulating factors. We conducted in-situ observations of soil greenhouse gas fluxes with the method of static chambers in a temperate broadleaf Korean pine forest in Changbai Mountain, and analyzed the impact of soil variables on greenhouse gas emissions. The results showed that soils acted as a CO₂ and N₂O source and a CH₄ sink during 2019-2021. The annual cumulative fluxes of soil CO₂, CH₄, and N₂O were 107.96±8.32, -50.99±7.41, and 10.17±2.41 mmol·m^-2·a^-1, respectively. Soil CO₂ emission and CH₄ uptake during the spring freeze-thaw period were significantly lower than those in the growing season, while N₂O emission was much higher. The cumulative fluxes of soil CO₂ and CH₄ during the spring freeze-thaw period contributed 5.51% and 8.44% to the annual total fluxes respectively, while the contribution of N₂O flux reached 51.43%. Multivariate regression analysis revealed that during the spring freeze-thaw period, CO₂ fluxes increased with rising soil temperature, and that soil temperature had minimal effects on CH₄ and N₂O fluxes. In the growing season, CO₂ fluxes were primarily influenced by soil temperature and soil NO₃^- content in surface layer. CH₄ fluxes were mainly regulated by soil moisture, while N₂O fluxes were weakly affected by soil pH. Soil freeze-thaw exerts a remarkable effect on the temporal variations of greenhouse gas emissions. Considering the complexity of soil C and N cycling and soil heterogeneity, more observations are required on greenhouse gas emissions and control mechanisms to accurately assess the role of soil in ecosystem C sequestration.





Drivers of the phylogenetic and functional diversity of evergreen and deciduous broad-leaved trees in the karst forests, eastern Yunnan.

LI Rong, WU Linyan, CHEN Qiuju, YIN Zhi, JIANG Yinping, ZHANG Chao, JIN Yi

2026, 45(8):  2553-2560.  doi:10.13292/j.1000-4890.202608.022

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The karst forests in the subtropical region of Southwest China harbor a rich diversity of deciduous and evergreen broad-leaved trees. Understanding their phylogenetic and functional diversity and the driving factors is key to elucidating mechanisms of community assembly and species coexistence in the karst forests. Focusing on woody angiosperms across 29 forest plots in Junzi Mountain in eastern Yunnan Province, we employed generalized linear models and Mantel test to analyze how environmental conditions and human disturbance shape diversity patterns. The results showed that: (1) Deciduous broad-leaved plants exhibited lower phylogenetic α-diversity (SES.MPD) but higher functional α-diversity (SES.MFPD) than their evergreen counterparts. While their phylogenetic β-diversity (SES.betaMPD) was similar, deciduous species showed significantly higher functional β-diversity (SES.betaMFPD). (2) Phylogenetic α-diversity in both tree types varied with soil type, being higher in black limestone soils than in brown limestone soils. However, their functional α-diversity responded to different drivers, which was correlated with human disturbance intensity in deciduous plants, but with slope aspect in evergreen plants. (3) The phylogenetic β-diversity of deciduous plants was influenced by human disturbance, whereas that of evergreen plants showed no environmental or anthropogenic correlations. Conversely, functional β-diversity varied with human disturbance in deciduous plants, but with slope aspect and soil type in evergreen plants. Our results revealed a clear divergence in the phylogenetic and functional diversity patterns of deciduous and evergreen broad-leaved trees in eastern Yunnan’s karst forests, reflecting their distinct adaptation strategies. These findings underscore the need for differentiated conservation and management approaches tailored to each plant functional type.





Carbon, nitrogen and phosphorus stoichiometric characteristics of leaves, litter, and soil of forests in the fragile region of southeastern Yunnan, China.

LI Jun, YU Jie, GONG Fei, HAN Duo, ZHOU Dekun, ZHAO Yuhui, LIU Honghao, FAN Ruyan, YU Yan

2026, 45(8):  2561-2571.  doi:10.13292/j.1000-4890.202608.020

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Understanding the carbon:nitrogen:phosphorus (C∶N∶P) stoichiometry and coupling in karst rocky-desertified and dry-hot valley forests is essential for nutrient management and ecological restoration. We quantified C, N, and P concentrations in foliage, freshly senesced litter and surface soils across five typical forest types in Mile and Shiping counties, southeastern Yunnan. The results were as follows. (1) Mean foliar C, N, and P concentrations were 426.69, 13.36, and 1.61 g·kg^-1 in Mile and 433.60, 12.19, and 1.26 g·kg^-1 in Shiping, respectively. Across all ecosystem compartments, Mile exhibited consistently lower C but higher N and P concentrations than Shiping. (2) Relative growth rates were below the global mean and followed the order of Mile>Shiping. Higher litter C∶N and C∶P ratios indicated slower decomposition in Shiping, mirroring its lower growth rates. (3) The resorption efficiency of N and P in Shiping was 52.7% and 69.5%, respectively, indicating a strong nutrient resorption effect. This suggests that plants adopt adaptive strategies such as altering root structures to enhance nutrient retention capacity under conditions of nutrient deficiency. (4) Foliar N∶P ratios (<14) revealed pervasive N limitation. However, the nutrient limitations varied among different forest types. Soil C∶P ratios suggested considerable P mineralization potential. We recommend enhancing soil nitrogen availability through N fertilization or replanting nitrogenfixing tree species in the understory. Our results can provide scientific basis for a better understanding of C, N and P biogeochemical cycles, as well as for the conservation and restoration of forest ecosystems in ecologically fragile areas.





Influencing factors of vegetation aboveground biomass recovery in burned areas of Daxing’an Mountains.

XU Xiaopeng, PAN Junxiao, GUO Meng, ZHANG Xinyu

2026, 45(8):  2572-2580.  doi:10.13292/j.1000-4890.202608.024

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Fire disturbance is a significant factor influencing aboveground biomass (AGB) in northern Chinese forests. The post-fire recovery of AGB depends on fire characteristics such as severity, frequency, and time since fire, and is also modulated by forest community structure. Elucidating the factors that drive AGB recovery in burned areas is essential for understanding community succession and carbon sequestration capacity in forest ecosystems. Focusing on the forests in the permafrost region of Daxing’an Mountains, a fire-prone area, we surveyed AGB and community structure in 2020 across 605 plots from large-scale burned areas with different fire histories, i.e., Mohe (burned in 1987), Huma (2003), and Songling (2006), along with 373 control plots, to analyze the effects of fire characteristics and forest community structure on AGB recovery. The results showed that: (1) AGB in the Mohe, Huma, and Songling burned areas (33, 17, and 14 years post-fire, respectively) was 81.1, 64.6, and 93.1 t·hm^-2, respectively. There were significant differences in AGB between burned and control plots in Mohe and Huma (P<0.05), but not in Songling (P>0.05). (2) Community diversity and stand age significantly influenced AGB in burned areas. Diversity and richness indices in burned areas were comparable to or significantly higher than those in control areas. Moreover, AGB in near-mature forests within burned areas more closely approached control levels than that in middleaged forests. (3) High fire severity significantly reduced AGB in burned areas. As fire severity increased (indicated by a decrease in the Normalized Burn Ratio), AGB exhibited a significant declining trend. (4) Fire severity and stand age explained 30% and 22% of the variation in AGB recovery, respectively, with contributions exceeding those of Shannon diversity index (10%) and species richness (5%). This study provides a scientific basis for understanding how fire disturbance and plant community structure jointly shape the patterns and drivers of AGB recovery in forest ecosystems.





Carbon storage of plants and soil organic carbon in the Northwest China desert region and the driving mechanisms.

KAN Zihan, GUO Hao, WANG Mingming, TAO Ye, YIN Benfeng, ZHOU Xiaobing, ZHANG Yuanming

2026, 45(8):  2581-2587.  doi:10.13292/j.1000-4890.202607.009

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Deserts play a crucial role in the global carbon cycle, with plant carbon storage (PCS) and soil organic carbon storage (SOCS) being vital for regional ecological stability and climate regulation. We used structural equation modeling (SEM) to assess the effects of climatic factors, plant functional traits, and soil properties on PCS and SOCS across 56 sites in deserts of northwest China. Results showed that the mean PCS was 13.59 g·m^-2 (CV=0.54) and the mean SOCS reached 642.38 g·m^-2 (CV=0.27), with both exhibiting primary spatial variation at the site level. PCS was primarily influenced by mean annual precipitation, community weighted mean nitrogen content, community weighted mean plant height, and soil water content. Plant traits exerted a significant positive effect on vegetation carbon storage. SOCS was primarily influenced by mean annual temperature and soil total nitrogen. Temperature exerted a significant negative effect on SOCS directly and indirectly through its impact on plant community nitrogen content and soil nitrogen content. Nitrogen cycling played a crucial role in the formation and stabilization of carbon stocks in desert regions. Soil total nitrogen exerted a significant positive effect on SOCS, while plant community nitrogen content also significantly positively influenced PCS. Our results further revealed the spatial heterogeneity of carbon stocks in deserts, with the differences of sampling sites being the primary source of variation, indicating strong spatial variability. This study provides an important theoretical basis for understanding carbon cycling in deserts and offers key strategies for enhancing soil nitrogen retention and water use efficiency in these regions, as well as for addressing the vulnerability of carbon pools.



Effects of intercropping and double-cropping of forage grasses and nitrogen application on soil nutrients and microbial diversity in the southern piedmont of the Greater Khingan Mountains.

WANG Zhe, LI Lijun, WANG Ying, HAN Li, JIN Haoqi, LI Xiaolong

2026, 45(8):  2588-2600.  doi:10.13292/j.1000-4890.202608.013

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To clarify the ecological consequence of efficient forage cropping patterns on soils in the black soil region of the southern foothills of the Greater Khingan Mountains, we used forage oat and forage rape as experimental materials, with a split-plot design being adopted. In the first season, the oat-rape intercropping pattern (FI) was uniformly applied. In the main plots, three double cropping patterns were deployed in the second season: oat monoculture (SO), rape monoculture (SR), and oat-rape intercropping (SI). In the subplots, four nitrogen application levels were set: 0 (N0), 75 (N1), 150 (N2), and 225 (N3) kg·hm^-2. Based on ITS rDNA and 16S rRNA gene sequencing, we investigated the effects of different intercropping and double cropping patterns and nitrogen application levels on soil nutrient contents and microbial community. The results showed that: (1) In terms of community composition, under the N2 treatment, continuous intercropping in the second season (SI) significantly changed the relative abundance of key phyla compared with that in the first season (FI). Specifically, the relative abundances of Gemmatimonadota and Mortierellomycota increased by 9.65% and 10.27%, respectively, while those of Actinobacteriota, Proteobacteria, and Ascomycota decreased by 10.91%, 16.56%, and 3.80%, respectively. (2) In terms of community diversity, cropping pattern and nitrogen application level had a significant interactive effect on the bacterial Chao1 and Shannon indices. Under each nitrogen application level, continuous intercropping in the second season (SI) increased the Chao1 indices of both soil bacteria and fungi compared with that in the first season (FI). The bacterial Chao1 index reached its highest value under the N2 level of the SI pattern. SI and SO patterns had high similarity in bacterial community structure, indicating the dominant regulatory role of oat on soil bacterial community under the intercropping system. LEfSe analysis of differential species further confirmed that the SI pattern had the most significant enrichment effect on characteristic dominant taxa of soil fungal community. (3) Spearman correlation analysis showed that Pseudogymnoascus was significantly positively correlated with soil TN and NO₃^--N, while Humicola and Cladosporium were significantly negatively correlated with soil NO₃--N. These genera can serve as microbial indicators for soil nitrogen cycling. In summary, the continuous intercropping pattern of two seasons per year combined with a nitrogen application level of 150 kg·hm^-2 exhibits significant advantages in optimizing soil microbial community structure, enhancing community diversity, and promoting synergistic nutrient transformation. Our findings provide a solid theoretical basis and technical support for the adjustment of grain-forage structure, efficient forage production, and sustainable utilization of black soil resources in the high-latitude cold pastoral area of the southern foothills of the Greater Khingan Mountains.





Effects of the succession of plateau zokor mounds on soil properties and microbial community in alpine meadow.

CHAI Yu, LI Xilai, LI Chengyi, ZHOU Yizhi, GAO Pei, ZHANG Jing, DU Xinru, ZHOU Xinian, WU Xiluo

2026, 45(8):  2601-2609.  doi:10.13292/j.1000-4890.202608.032

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A large number of bare mounds are formed by plateau zokor (Eospalax baileyi) interference in alpine meadows in the source region of the Yellow River. After the interference disappeared, the bare mounds naturally recover, which may alter the stability of grassland soil microbial community. The responses of soil characteristics and microbial community stability to the succession of bare mounds remain unclear. In this study, we analyzed the variations of soil properties and soil microbial community across three succession stages of zokor mounds in the source region of the Yellow River, including bare mounds (BM), short-term recovery mounds (SM) and long-term recovery mounds (LM), with healthy alpine meadow (YS) as the control. The results showed that soil moisture, soil water-holding capacity, soil bulk density, soil organic carbon and total nitrogen content gradually increased from bare mounds to long-term recovery mounds, with the growth rates being 26.48%, 1.90%, 36.14%, 15.87%, and 39.89% respectively. Soil conductivity gradually decreased, and soil β-glucosidase and alkaline phosphatase activities were higher in the recovery stage. Shannon diversity index, Pielou evenness index, resistance and resilience of soil bacteria and fungi as well as the niche breadth of soil bacteria increased with the recovering succession of bare mounds, Soil bacterial community stability had a strong correlation with soil physical properties (soil moisture, soil water-holding capacity, bulk density and conductivity) and organic carbon content, while soil fungal community stability had a strong correlation with soil β-glucosidase and alkaline phosphatase activities and organic carbon content. This study reveals the variations of soil microbial community stability during the recovering succession of plateau zokor bare mounds, which provides a theoretical basis for understanding the management and restoration strategy of alpine meadows in the source area of the Yellow River.





Effects of nitrogen and phosphorus addition on soil organic carbon components of alpine grassland.

QIN Jiahao, ZHANG Xiaodong, DONG Shikui, SONG Zhaoliang

2026, 45(8):  2610-2620.  doi:10.13292/j.1000-4890.202608.030

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The stability of soil organic carbon (SOC) is a key indicator for assessing the carbon sink function of alpine grasslands, and its dynamics are regulated by the biogeochemical cycles of nitrogen (N) and phosphorus (P). However, the response mechanisms of different carbon components (such as particulate organic carbon (POC) and mineral-associated organic carbon (MAOC)) in alpine grasslands to N and P additions remain unclear. A field experiment was conducted to investigate the response mechanisms of different soil carbon components to N and P additions in an alpine grassland of the Qinghai-Tibet Plateau. The results showed that N addition significantly increased SOC content in the surface soil (0-10 cm) and that the combined N and P addition significantly increased SOC reserves. Both N and P addition caused a significant decrease in soil pH. Single N addition and the combined addition of N and P significantly increased the EC, ASi content, and NH₄⁺-N content in the topsoil (0-10 cm). In the subsurface soil (10-20 cm), N and P addition had no significant effect on most basic soil physical and chemical properties, except for soil SOC and ASi content. Basic soil physical and chemical properties such as SOC, TN, TP, EC, NH₄⁺-N, and ASi all decreased significantly with increasing soil depth. In the surface soil (0-10 cm), N addition significantly promoted the accumulation of POC and MAOC, with their contents reaching the maximum under the synergistic effect of N and P addition. However, single P addition inhibited the formation of POC and MAOC. In the sub-surface soil (10-20 cm), the effects of N and P addition on POC and MAOC were weaker, with MAOC exhibiting higher stability. Correlation analysis showed that the POC content was significantly negatively correlated with soil pH and significantly positively correlated with TN and NH₄⁺-N content, while soil MAOC content was significantly positively correlated with ASi. In summary, N and P addition has a significant synergistic effect on soil carbon storage in alpine grasslands. This study provides important scientific basis for the sustainable management of alpine grasslands and the enhancement of their carbon sink functions. In the future, optimizing nutrient management strategies can promote the conversion of POC to MAOC in alpine grasslands, thereby enhancing the long-term stability of soil carbon pools.





Effects of soil bulk density and aggregate size on nitrous oxide and dinitrogen emissions from Northeast China Mollisols under varying oxygen conditions.

WEI Huanhuan, JIANG Lixing, TAN Yuechen, WU Di

2026, 45(8):  2621-2632.  doi:10.13292/j.1000-4890.202608.036

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The Mollisol belt of Northeast China is currently experiencing problems such as deterioration of soil structure, thinning of topsoil layer, and decline in fertility, which may have an adverse impact on soil nitrogen transformation. We investigated the effects of soil bulk density and aggregate size on nitrogen cycling and gaseous nitrogen losses in Mollisols from Northeast China. Two groups of treatments were established using a Roflow automated helium-based soil incubation monitoring system: one manipulating bulk density (1.0, 1.2, 1.4, and 1.6 g·cm^-3), and the other varying soil aggregate sizes (unfractionated, <1, 1-2, and 2-4 mm). Emissions of N₂O and N₂ were continuously monitored under both aerobic (20% O₂ + 80% He) and anaerobic (100% He) conditions. Coupling these observations with changes in inorganic nitrogen and the N₂O/(N₂O+N₂) ratio, we explored how soil physical structure regulates the emission pathways of N₂O and N₂. Results showed that both bulk density and aggregate size significantly affected N₂O and N₂ emissions. Under aerobic conditions, the 1.4 g·cm^-3 treatment exhibited the highest N₂O emission. Under anaerobic conditions, the 1.6 g·cm^-3 treatment had 55.1% higher cumulative N₂O emission than other treatments. The intermediate aggregate size (1-2 mm) treatment resulted in the highest N₂O emission peaks and cumulative emission and inhibited the reduction of N₂O to N₂. These findings suggest that moderate bulk density promotes nitrification-derived N₂O emissions, whereas high bulk density enhances denitrification-derived N₂O production under anaerobic conditions. Coarser aggregates (2-4 mm) and unfractionated soil (intact structure) exhibited better aeration and higher net nitrification rates, while fine aggregates showed the weakest nitrification potential. There was a significant positive correlation between N₂O emissions and net nitrification rates under varying bulk density treatments, while there was a significant negative correlation under different aggregate size treatments (P<0.01). Those results indicate that micro-environmental changes induced by soil physical structure play a critical role in modulating nitrification and N₂O reduction processes. Overall, our results elucidate the mechanistic differences in nitrogen transformation and N₂O emission pathways regulated by soil structure in the Mollisols of Northeast China. These insights provide a theoretical basis for optimizing soil physical properties to mitigate gaseous nitrogen losses and improve nitrogen use efficiency.





Effects of no-tillage with straw mulching on soil physicochemical properties and maize yield in western Liaoning.

GAN Miao, ZHANG Zhenzi, DONG Zhi, DONG Jun, LIU Yang, HOU Zhiyan, SUN Zhanxiang

2026, 45(8):  2633-2642.  doi:10.13292/j.1000-4890.202608.007

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To construct conservation tillage practices with the aim of maintaining high and stable maize yield in the semi-arid region of western Liaoning, a field experiment was conducted with three treatments: conventional rotary tillage (RT), no-tillage without straw mulching (NT), and no-tillage with straw mulching (NTS). We analyzed the effects of these treatments on soil hydrothermal conditions, physicochemical properties, and maize yield. The results showed that: (1) Under precipitation-deficient conditions during the 2017 and 2018 growing seasons, maize yield under NTS was significantly higher than that under NT and RT. Compared to RT, NTS increased maize yield by 12.44% and 22.96% in 2017 and 2018, respectively. However, in a wet year (2021), the yield-promoting effect of NTS was not significant. (2) Compared to RT, NT improved water retention in the 0-20 cm soil layer, whereas NTS promoted downward water movement and maintained smaller moisture fluctuations during the rainy season (June-September). NTS regulated soil temperature in the 0-20 cm layer, exhibiting a cooling effect in spring and early summer but a warming effect in autumn and winter. (3) Both NT and NTS significantly improved soil physical structure in the 0-20 cm layer, with the impact of NTS being the strongest. The generalized soil structure index for NTS was 8.24% higher than that of NT, while the soil three-phase structure distance was 3.38% lower than that of NT. (4) Surface accumulation of soil organic matter, total nitrogen, and available potassium was more pronounced under NT and NTS. The NTS treatment ensured yield stability by regulating soil moisture, temperature, pH, total nitrogen, and available phosphorus. Notably, continuous no-tillage increased soil bulk density, requiring timely management (e.g., subsoiling tillage) to prevent severe compaction. These findings provide a theoretical basis and technical support for enhancing maize yield and optimizing tillage systems in the semi-arid region of western Liaoning.





The driving mechanism of artificial grass cover duration on N₂O emissions from citrus orchard soils.

YANG Hongbing, ZENG Lixiong, LEI Lei, ZHANG Jiajia, YANG Xin, HUANG Zhilin, XIAO Wenfa

2026, 45(8):  2643-2653.  doi:10.13292/j.1000-4890.202608.010

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To assess the potential of soil greenhouse gas emissions in citrus orchards of the Three Gorges Reservoir Region and to inform management optimization, we examined fertilized non-rhizosphere topsoil (0-10 cm) under four treatments: clean tillage (CK) and cover cropping with smooth vetch (Vicia villosa) established for 4, 7, and 11 years. Gas fluxes from soils were determined by the field in-situ measurement method, and soil physicochemical properties and microbial characteristics were analyzed to explore the driving mechanism of smooth vetch cover duration on nitrous oxide (N₂O) emissions. Smooth vetch cover significantly increased N₂O emission by 42.7%, and enhanced soil capillary porosity, β-glucosidase activity, and CO₂ emission. The N₂O emission presented a dynamic trend of rising first and then declining with increasing cover duration. Cover duration significantly affected soil pH and the mean weight diameter of water-stable aggregates (W_MWD). N₂O flux was negatively correlated with NH₃ and CH₄ fluxes but positively correlated with CO₂ flux (P<0.05). The primary drivers of N₂O flux were soil moisture, W_MWD, and N-acetyl-glucosaminidase activity. Partial least squares path modeling (PLS-PM) indicated that the duration of smooth vetch cover modulated N₂O emission by influencing soil moisture, enhancing aggregate stability, and optimizing the microbial threshold elemental carbon-to-phosphorus ratio (TER C∶P ratio). The synergistic effect of core driving factors explained 95.8% of the variation in N₂O emission. Overall, extending the duration of smooth vetch cover can effectively suppress N₂O emission by strengthening soil aggregate stability and optimizing TER C∶P ratio, providing a scientific basis for N₂O mitigation in citrus orchards of the Three Gorges Reservoir Region.





Effects of straw strip mulching combined with microbial fertilizer on water consumption characteristics and yield of waxy sorghum under extreme drought.

CHEN Yuzhang, CHEN Mingyang, LIU Xin, LI Rui, WANG Licheng

2026, 45(8):  2654-2664.  doi:10.13292/j.1000-4890.202608.009

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Against the backdrop of climate change, extreme drought has become the primary water constraint for agriculture in drylands. A field experiment was conducted in a severe drought year, using the waxy sorghum cultivar “Yiwuhong 4”. There were four treatments: straw strip mulching (SSM), SSM with conventional microbial fertilizer (MSM), SSM with biochar-based microbial fertilizer (BSM), and flat planting without mulching (NM) as the control. Results showed that the SSM, MSM, and BSM treatments significantly increased the average soil water storage in 1-m soil profile by 21.8 mm (a 9.0% increase) while decreased total water consumption by 30.8 mm (an 8.5% reduction) during the sorghum growth period from jointing to maturity. Moreover, these mulching treatments (SSM, MSM, BSM) optimized water consumption structure and reduced soil water depletion by 28.9-31.9 mm, with the majority of this reduction occurring in the shallow surface (0-20 cm) and deep soil layers (below 60 cm). The application of microbial fertilizer further enhanced soil moisture conservation effect of SSM. Compared to SSM alone, the MSM and BSM treatments significantly increased soil water storage by 3.1%-4.9% during the jointing to booting stage. This enhanced water status promoted vegetative growth (plant height, leaf area, stem diameter, and biomass), driving substantial increases in grains per spike (41.5%-55.6%) and grain weight per spike (18.2%-32.5%). Ultimately, these treatments achieved yield increases by 21.8%-27.7% and improved water use efficiency by 30.9%-39.4%, with BSM performing best. Thus, BSM is the recommended practice for water-saving, high-yield sorghum production under extreme drought in the hilly purple soil areas of southwest China.





Morphological and physiological responses of Medicago sativa seedlings to multiple stresses.

LI Meng, HU Mingxin, CHEN Jiahui, ZHANG Yu, LU Shengyuan, TIAN Yu

2026, 45(8):  2665-2671.  doi:10.13292/j.1000-4890.202607.018

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Due to global climate change and the limitations of land resources, the cultivation and growth of Medicago sativa are influenced by multiple stresses. In this study, M. sativa cv. Aohan was subjected to various single and multifactorial stressors. The treatments included stressors of alkaline salt (A, 100 mmol·L^-1 NaHCO₃), neutral salt (S, 100 mmol·L^-1 NaCl), phosphorus deficiency (P, 10% KH₂PO₄ in HoagLand nutrient solution), heavy metal (Cd, 5 μmol·L^-1 CdCl₂), and drought (D, 30% water supply), along with unstressed control (CK, Hoagland nutrient solution). This setup allowed for a comprehensive evaluation of the eco-physiological responses of M. sativa cv. Aohan seedlings to diverse abiotic stressors. The results showed that the inhibitory effects of multifactorial stresses on plants were significantly higher than those of single stress, with the alkaline salt stress playing a dominant role in all combinations. Taking A+D+P stress as an example, aboveground growth and photosynthetic capacity were severely impaired, with plant height reduced by 43.05% and significant decline in relative chlorophyll content. The morphogenesis of root system underwent adaptive reshaping, showing reductions in total root length, surface area, and volume by 83.74%, 81.44%, and 78.92%, respectively, while the average root diameter increased by 16.22%. In addition, to counteract oxidative damage, the superoxide dismutase activity in leaves increased by 136.36%. Our results indicate that M. sativa cv. Aohan seedlings can mitigate adverse effects of multiple stresses through synergistic responses involving root morphological reshaping and antioxidant regulation.





Selenium enrichment and its controlling factors in soil-crop system of the red soil region in South China.

ZHANG Ge, ZHAO Yi, QIU Zitai, LI Shuaibei, WANG Qiugui, XIAO Enzong, XIAO Tangfu

2026, 45(8):  2672-2680.  doi:10.13292/j.1000-4890.202608.033

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Soil Se is primarily derived from parent rocks. However, the mechanisms of Se migration and transformation during weathering and soil development, as well as their effects on crop accumulation, remain unclear. Soils derived from basalt (Xuwen, Zhanjiang) and granite (Yamen, Jiangmen) weathering in the red soil region of South China both exhibit Se enrichment (>0.4 mg·kg^-1). We analyzed the geochemical distribution of Se in the “parent rock-soil-crop” system. The results showed that the Se content in basaltderived soils (1.04 mg·kg^-1) was higher than that in granite-derived soils (0.90 mg·kg^-1), which was closely related to differences in parental rock composition and weathering processes. The migration and transformation of Se at the rock-soil interface were mainly influenced by soil Al, Fe, S, and pH. The Se accumulation capacity in crops was similar in both regions. In the basalt region, 25% of rice samples and all vegetable samples met the Se-rich criteria, while31.25% of rice samples and 77.14% of vegetable samples reached the Se-rich standard in the granite region. Furthermore, the Se content in crops was significantly positively correlated with the Ca content and soil pH, indicating that Ca affects the bioavailability absorption and accumulation of Se in crops mainly by regulating soil acidity and ion balance. These findings provide new insights into the biogeochemical behavior of Se in geological high-background regions and offer a scientific basis for evaluating the mechanisms of natural Se enrichment in soils and its rational utilization.





Response of four Hosta species to cadmium stress and evaluation of their tolerance to cadmium.

SUN Xiaogang, LI Baizhou, ZHU Chunyao, LUAN Lihong, TIAN Ziyuan, LI Bo, MU Jiaqi, YIN Jiahui

2026, 45(8):  2681-2691.  doi:10.13292/j.1000-4890.202607.013

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With the advancement of industrialization in Jilin Province, soil cadmium (Cd) pollution has posed challenges to the cultivation of ornamental horticultural plants. Hosta plants, known for their strong tolerance to Cd stress and outstandingly ornamental characteristics, could be open-field cultivated in Changchun. Taking four Hosta cultivars as experimental materials, namely H. ‘Golden Cadet’, H. ‘Blue Cadet’, H. ‘Flos Lotus’, and H. ‘Golden Tiara’, we investigated the effects of different Cd concentrations (1, 5, 50, 100, and 175 mg·kg^-1) on the growth, photosynthesis, and the antioxidant system of Hosta cultivars. By using principal component, membership function, correlation analysis and clustering analysis, Cdtolerance cultivars and evaluation indicators were screened. The contents of soluble protein and soluble sugar, as well as the activities of superoxide dismutase and peroxidase in all the four cultivars first increased and then decreased with increasing Cd concentration. Under 175 mg·kg^-1 Cd treatment, the increase in soluble sugar content of H. ‘Blue Cadet’ relative to the control was 5.3%, 2.0%, and 5.4% higher than H. ‘Golden Cadet’, H. ‘Flos Lotus’, and H. ‘Golden Tiara’, respectively. Moreover, the increases in peroxidase activity of H. ‘Blue Cadet’ relative to the control were 19% higher than H. ‘Flos Lotus’ under 175 mg·kg^-1 Cd treatment. The comprehensive evaluation value (D) of H. ‘Blue Cadet’ was consistently higher than those of other cultivars across different Cd treatments, indicating that it had the highest Cd tolerance. According to the correlation analysis under 100 mg·kg^-1 Cd treatment, four Hosta cultivars exhibited different Cd tolerance. The D value was significantly positively correlated with plant height, leaf length, leaf number, soluble protein content, and relative water content, which could be used as a key parameter for assessing Cd tolerance. In conclusion, Hosta alleviates the inhibitory effect of Cd stress on photosynthetic intensity by increasing osmoregulatory substance content and antioxidant enzyme activities, and enhancing osmotic adjustment and antioxidant capacities. Our results provide reference for the cultivation of ornamental horticultural plants and landscaping in Cd-contaminated soil in northeast China.





Effects of fertilization status and egg age of Corcyra cephalonica on the parasitism behavior of Trichogramma chilonis.

ZHANG Ye, QIAO Qingyun, ZHOU Jin, WANG Juan, ZHANG Hui, ZHU Wenya, MA Ruiyan

2026, 45(8):  2692-2698.  doi:10.13292/j.1000-4890.202608.006

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Corcyra cephalonica eggs serve as an essential host for the mass production of the parasitoid wasp Trichogramma chilonis, with the age and fertilization status of host eggs  significantly influencing rearing efficiency. We recorded the duration and frequency of parasitic behaviors (egg surface probing, oviposition, resting and feeding) of female T. chilonis on fertilized and unfertilized C. cephalonica eggs aged 0-96 hours. Results showed that visitation frequency of wasp to host areas declined markedly with increasing egg age (e.g., from 4.80 visits at 0 hour old to 2.70 visits at 48 hours old). Wasps spent consistently longer time probing unfertilized eggs compared to fertilized ones, with a significant difference being observed at 72 hours old (23.36 s vs. 20.02 s). At 24 hours old, oviposition frequency was significantly higher on fertilized eggs than on unfertilized eggs (3.70 vs. 2.95 events). Regardless of fertilization status, mean oviposition frequency was greater in the 0-48-hour-age group (1.90-2.05 events) than in the 72-96-hour-age group (1.60-1.75 events). In contrast, host-feeding behavior exhibited no consistent preference related to egg age or fertilization status. These findings demonstrate that the parasitic behavior of T. chilonis is jointly modulated by host egg age and fertilization status, reflecting a clear preference for younger and fertilized hosts, along with a significant decline in area visitation as host age increases. This study provides an ethological basis for optimizing mass production of T. chilonis through the selection of younger, fertilized C. cephalonica eggs.





Fluoride removal performance and mechanism of microbially induced calcite precipitation enhanced by Fe-Al modified oyster shell substrate.

DAI Yile, GUAN Yong, MAO Xin, WANG Xueqi, SONG Jingxin, SUN Junqi, WANG Sen, KONG Fanlong

2026, 45(8):  2699-2708.  doi:10.13292/j.1000-4890.202608.037

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Microbial defluorination has the advantages of green and low-cost relative to other technologies, but  F^- may inhibit the activities of key enzymes of microbial metabolism, thus reducing the removal effect. In this study, a carrier was prepared using oyster shell powder and the activity of carbonic anhydrase (CA) was enhanced through Fe-Al modification, to strengthen the microbially induced calcium precipitation (MICP) process for F^- removal. The orthogonal experiment results showed that the removal effect of F^- was the best (up to 92.0%) when the calcination temperature was 700 ℃, Fe∶Al=2∶1, and the mass ratio of oyster shell powder to sodium alginate (NaAlg) and ammonium bicarbonate (NH₄HCO₃) was 4∶0.1∶0.2. Moreover, after five cycles of regeneration, the removal efficiency could reach 81.5%, showing good regeneration performance. The screened Fe-Al modified substrate was used to enhance MICP for F^- removal, and the removal efficiencies of F^-, NO₃^--N and TP could reach 84.9%, 100% and 53.5%, respectively. By combining enzyme activity analysis and biological precipitation characterization, the mechanism by which the Fe-Al modified substrate enhanced MICP for F^- removal could be attributed to the complexation reaction between Fe and Al and F^-. Such interaction reduced the toxicity of F^- in the solution, improved the tolerance of microorganisms to F^-, and significantly enhanced the activity of microbial CA, thus achieving the simultaneous removal of F^-, NO₃^--N and TP through promoting the MICP process. This study provided theoretical basis and efficient and feasible technical support for treating water containing F^- through the combination of substrate preparation and microbial treatment.





Analysis and optimization of spatiotemporal patterns of the urban thermal environment in Xi’an based on local climate zones.

YAO Jiaqi, YANG Liping, YANG Jiajia, GAO Meiling, DU Bin, SUN Jiajun

2026, 45(8):  2709-2717.  doi:10.13292/j.1000-4890.202608.004

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Alleviating urban thermal environment effect and adjusting urban landscape layout are crucial for improving human settlement comfort and promoting sustainable urban development. Based on multiple Landsat 8 remote sensing data of the main urban area of Xi’an, Shaanxi Province, we explored the spatiotemporal variations of land surface temperature (LST) with the mean-standard deviation and regional analysis methods. Combined with the local climate zone (LCZ) theory, the contribution index was used to quantitatively analyze the influence of 17 LCZs on urban heat island effect, and Cplex solver was utilized to optimize LCZs. The results showed that: (1) The heat island effect exhibited distinct spatial heterogeneity and seasonal variations. In spring, the thermal landscape pattern showed a patchy distribution. In summer, the heat island spatial agglomeration effect was enhanced significantly. There was a "dual core" model in autumn and a unique “cold center and hot periphery” structure in winter. (2) LCZs of built-up area generally had higher LST than natural areas, especially LCZ2 (compact midrise) and LCZ8 (large low-rise). Natural areas such as LCZ11 (dense forest) and LCZ12 (sparse forest) had the lowest LST. LCZ2, LCZ5 (open midrise) and LCZ8 all showed high thermal contribution in spring, summer, and autumn. LCZ17 (water) exhibited the significant cold contribution, and LCZ14 demonstrated the most prominent fractional vegetation cover (FVC) contribution. LCZ1 (compact highrise), LCZ2 and LCZ4 (open high-rise) constituted the primary population agglomeration areas, while LCZ5 stood out in both FVC and population density contribution. (3) After optimization, the areas of LCZ2, LCZ11, LCZ12, and LCZ17 increased by 13.5 to 119.2 km², and those of LCZ3, LCZ5, LCZ7, and LCZ8 decreased by 5.2 to 259.9 km². LST declined from 39.94 to 38.81 ℃. To promote sustainable urban development, the areas of LCZ5 and LCZ8 should be constrained, while those of LCZ11 and LCZ17 should be increased.



Assessing the accessibility of urban park green space in different grades of cities by combining subjective and objective aspects.

WU Wen, LI Liushuxin

2026, 45(8):  2718-2726.  doi:10.13292/j.1000-4890.202608.028

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In the research area of urban green space (UGS), accessibility has emerged as a pivotal area of focus. Among the various analytical tools, the Gaussian two-step floating catchment area method (G2SFCA) has garnered significant academic attention due to its cutting-edge capabilities for quantitative analysis. However, there are two major limitations in current studies. First, they often overlooked the subjective perceptions of residents. Second, there was a notable deficiency in comparative analyses of different urban types at the regional scale. Taking the central and southern Liaoning urban agglomeration as a case study, we constructed a G2SFCA model that integrated both subjective and objective elements. This integrated model was employed to systematically evaluate the accessibility characteristics of UGS across cities of varying grades. The results showed that medium-grade cities exhibited the highest accessibility (99.97), followed by highgrade cities (85.40) and low-grade cities (69.46). Moreover, the spatial differentiation within cities of different grades was markedly distinct. Correlafion analysis excluding other urban-specific characteristics indicated that natural geographical conditions did not exhibit significant correlations with either average accessibility or urban grade. While social and economic factors were not significantly related to average accessibility, they were strongly correlated with urban grade. This suggested that the ranking relationship between urban grade and average accessibility was not affected by other factors. We proposed that urban green space system planning should holistically consider the regional economic development level and the spatial distribution patterns of the population, and implement differentiated strategies accordingly. High-grade cities should prioritize enhancing the quality of existing green spaces. Medium-grade cities should focus on integrating existing resources across districts. Low-grade cities should adopt a “precise supplementation” strategy, moderately developing natural resources on their peripheries. In summary, our results provide a robust scientific foundation for urban park green space planning that balanced regional integrity with urban differences, which would help formulate more targeted hierarchical construction strategies and promote the goal of achieving social equity in the distribution of green resources.





Potential distribution of Alcimandra cathcartii in China under future climate scenarios.

MA Ting, YANG Guanglei, WANG Zijuan

2026, 45(8):  2727-2737.  doi:10.13292/j.1000-4890.202608.015

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Alcimandra cathcartii is a Class II nationally protected plant species in China, facing severe threats from climate change. In this study, we predicted changes in its suitable habitat across China under current conditions and four future periods (2030s, 2050s, 2070s, and 2090s) across three climate scenarios (SSP126, SSP245, and SSP585), by combining an optimized MaxEnt model with multivariate environmental similarity surface (MESS) and most dissimilar variable (MoD) analyses. Results indicated reliable model predictions (area under the receiver operating characteristic curve AUC >0.97, true skill statistic TSS >0.93, continuous Boyce index CBI >0.94). Temperature seasonality, precipitation in the hottest quarter, isothermality, precipitation in the coldest quarter, elevation, and mean temperature in the hottest quarter were identified as the key environmental factors influencing the geographical distribution of this species. The current total area of suitable habitat was 76.62×10⁴ km², accounting for 7.98% of total land area in China, with highly suitable habitat (13.01×10⁴ km²) being concentrated in southwestern to southeastern Yunnan and southern Tibet. Under future climate scenarios, the suitable habitat area showed an overall trend of first increase followed by a gradual slowdown. Under the SSP126 scenario, the highly suitable habitat peaked at 35.50×10⁴ km² in the 2070s before contracting. Under the SSP245 scenario, the overall suitable habitat (lowly, moderately, and highly suitable habitats) remained relatively stable. However, under the high-emission scenario (SSP585), degradation risks were most pronounced. The highly suitable habitat sharply declined to 24.58×10⁴ km² in the 2070s. Although it partially recovered by the 2090s, habitat fragmentation in the core areas continued to intensify. Climate anomaly zones expanded overall with increasing emission intensity. The dominant anomaly factors gradually shifted from precipitation-related factors to temperature factors, with the vulnerability of southern concentrated suitable habitats and southeastern marginal areas significantly increasing. Centroid migration analysis showed that the centroids under the SSP126 and SSP245 scenarios migrated overall toward the northeast compared to the current period, while under the SSP585 scenario the migration direction shifted successively compared to the preceding period during the later periods (2050s-2090s), toward the southwest in the 2050s, toward the northwest in the 2070s, and toward the south in the 2090s, reflecting the high instability of suitable habitats under high-emission scenarios. The Yunnan-southern Tibet region is recommended as a priority core conservation area.





Trade-offs and synergies between tourism and ecosystem services and their influencing factors in  Xin’an River Basin.

GUO Beibei, ZOU Xian, BAO Jie

2026, 45(8):  2738-2746.  doi:10.13292/j.1000-4890.202608.017

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Understanding the social and natural factors that affect the spatial and temporal patterns of ecosystem services in tourist destinations is important for achieving sustainable management and environmental protection. We quantitatively investigated the spatial distribution of ecosystem services in the Xin’an River Basin using the Pearson correlation coefficient method. Geographic probes were introduced to identify the driving factors affecting the spatial distribution of ecosystem services and analyze the intrinsic logic between spatial differences and the development of tourist destinations. The results showed that: (1) Soil conservation in the Xin’an River Basin maintained at 0-713.97 t·hm^-2. Water yield was 286.93-2060.29 mm. Average habitat quality was 0.81. Carbon storage was 2.3-106.55 t·hm^-2. Tourism culture was 0-5922 yuan·hm^-2. (2) The areas with high water yield in the Xin’an River Basin were mainly concentrated in the Huangshan Mountain and the southern hills regions. The areas with low water production value were located around Taiping Lake and the Xin’an River. The areas with high value for soil conservation were found in the Huangshan Mountains, the southern part of Huangshan City, and the border between Huangshan City and Hangzhou City. Low-value areas were mainly found in the central and eastern parts of the basin. Except for the central regions (including the Huangshan Scenic Area, Tunxi District, and Huizhou District) and the Xin’an River, carbon stock and habitat quality showed obvious clustering in other areas. High-value areas for tourism culture were mainly distributed along the Xin’an River and other water bodies, while cultivated land areas had the lowest values. (3) The relationships among the five ecosystem services in the Xin’an River Basin were primarily synergistic. There were trade-off relationships between tourism culture and carbon storage, soil conservation, water supply, as well as between water supply and habitat quality. The most significant trade-off was found between tourism and water supply, while the most prominent synergy was between tourism and habitat quality. (4) Natural factors were the dominant factors influencing the five types of ecosystem services in the Xin’an River Basin, but the impacts of social factors on ecosystem services should not be underestimated.





A review of research content and methodological paradigm shifts in food web stability.

LIU Junwei, LI Xingchun, ZHOU Xuehong

2026, 45(8):  2747-2757.  doi:10.13292/j.1000-4890.202608.019

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The stability of food webs is a hot topic in food web studies. It determines the capacity of food webs to maintain their structure and functions under disturbances, and generally involves multi-dimensional assessments including persistence, resistance, resilience, and robustness. We focused on the theoretical basis of food web stability. Starting from the “complexity-stability paradox” and the controversies it has triggered, we reviewed the structural characteristics of food webs and their responses to disturbances, and summarized the research progress and main research directions of local stability and overall stability. We further reviewed the research methods for food web stability, ranging from traditional field investigations to emerging technologies based on big data and machine learning, highlighting that interdisciplinary integration represents the future trend of methodological development in this field. The traditional modeling methods and emerging technologies such as artificial intelligence each have distinct advantages and limitations. Future research should promote their integration by drawing on each other’s strengths and compensating for respective weaknesses, to advance key research directions including the construction of multi-scale dynamic coupling models, the analysis of critical threshold mechanisms, and the identification of early warning signals. This review provides a systematic framework for understanding the operational mechanisms of food web stability and offers a reference for addressing ecosystem transformations induced by climate change and human activities.





Research progress on the role of cable bacteria in biogeochemical cycling and water environment restoration.

ZHOU Ying, XIONG Xinyan, ZHANG Chi

2026, 45(8):  2758-2768.  doi:10.13292/j.1000-4890.202608.018

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Since the discovery of cable bacteria in sediments in 2012, they have attracted considerable attention for their remarkable capacity in mediating centimeter-scale long-distance electron transport. They are globally distributed in marine and freshwater. Their survival depends on the access to electron donors (sulfides) and acceptors (oxygen), and their species composition and diversity is determined by salinity. Cable bacteria can bridge oxic and sulfidic zones, functioning as biological conductors through electrogenic sulfur oxidation (e-SOx) to spatially separate oxidation and reduction reactions, create suboxic zones, and drive the biogeochemical cycling of key elements, including sulfur, iron, calcium, manganese, nitrogen, and phosphorus. In the restoration of aquatic ecosystems, cable bacteria show considerable potential to alleviate hypoxia and eutrophication, degrade toxic and hazardous pollutants, facilitate heavy metal removal, mitigate greenhouse gas emissions, and improve the rhizosphere conditions of aquatic plants. They can also be coupled with other technologies such as microbial electrochemical snorkels, microbial fuel cells, and aeration, to enhance restoration efficiency. In this review, we systematically summarized the distribution of cable bacteria in aquatic ecosystems and the major environmental factors affecting their survival and composition, analyzed the fundamental role of cable bacteria in the biogeochemical cycling of key elements in sediments, and discussed the exploration of cable bacteria in pollution control and aquatic ecosystem remediation. We highlighted the key discoveries, opportunities, and challenges of their role in aquatic environment remediation, and proposed a constructive outlook.





Application of three-dimensional excitation-emission matrix fluorescence spectroscopy in the study of atmospheric organic aerosols.

ZHAO Jiaming, DENG Junjun, WU Libin, FU Pingqing

2026, 45(8):  2769-2776.  doi:10.13292/j.1000-4890.202608.035

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As an important component of atmospheric aerosols, organic aerosols have complex sources and transformation mechanisms. Threedimensional excitation emission matrix fluorescence spectroscopy (3D-EEM), featuring high sensitivity, convenience, and nondestructive analysis of sample structures, has been widely used in studies to understand the composition, sources, and transformation mechanisms of organic aerosols. By integrating fluorescence parameters with analytical approaches such as peak identification, fluorescence regional integration (FRI), and parallel factor analysis (PARAFAC), the 3D-EEM technique could effectively elucidate the chemical characteristics of fluorescent components across different solubility fractions and quantify chemical composition of aerosols from diverse sources. Moreover, 3D-EEM has also been combined with complementary techniques, such as ultraviolet-visible (UV-Vis) absorption spectroscopy, infrared spectroscopy, gas chromatography, and ultra-high-resolution mass spectrometry, to reveal the relationships between fluorescent chromophores, light absorption properties, and molecular structures of aerosols. To address those gaps, future efforts should prioritize the development of online 3D-EEM monitoring techniques, establish fluorescence parameter frameworks tailored to atmospheric conditions, expand the fluorescence characterization of fully dissolved components, and integrate machine learning to explore the correlations among fluorescence spectra, molecular compositions, and environmental effects. These efforts will further enhance the understanding of the source apportionment and environmental effects of organic aerosols, providing scientific insights for regional pollution control and climate model optimization.





Differences in soluble organic carbon and nitrogen in soil and organic materials: A comparative study based on weak and strong extractants.

ZHU Yi, QUAN Zhi, WEI Fulong, LIU Chang, MA Jian, LU Caiyan, CHEN Xin, SHI Yi, FANG Yunting

2026, 45(8):  2777-2786.  doi:10.13292/j.1000-4890.202608.034

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Extractable carbon and nitrogen fractions are key components in soils and organic materials, directly influencing soil quality and biogeochemical cycling through their contents and variability. We investigated nine soils and six organic materials that were extracted using two extractants, 0.01 M CaCl₂ (weak extraction) and 0.5 M K₂SO₄ (strong extraction), to compare the variations in extractable organic carbon (EOC) and organic nitrogen (EON). The results showed that: (1) EOC and EON concentrations in soils ranged from 13.1 to 390.8 mg·kg^-1 and 3.3 to 30.3 mg·kg^-1, respectively. On average, CaCl₂ and K₂SO₄ extracted EOC accounted for 79%±22% and 88%±16% of total extractable carbon (TEC), while EON represented 10%±10% and 20%±14% of total extractable nitrogen (TEN), respectively. (2) Organic materials exhibited significantly higher EOC (1.2-77.1 g·kg^-1) and EON (0.4-8.5 g·kg^-1) levels, with EOC/TEC (96%-97%) and EON/TEN (71%-85%) markedly exceeding those in soils. (3) There was a significant negative correlation between SUVA₂₅₄ (specific ultraviolet absorbance at 254 nm) and EOC/EON ratios, indicating that low C/N extractable organic components were enriched in aromatic structures. (4) In soils, CaCl₂ extracted EOC and EON accounted for 19%±8% and 44%±20% of K₂SO₄ extracted amounts, respectively, suggesting that weak extraction preferentially mobilized low C/N fractions and that strong extraction released more high C/N fractions. For organic materials, the absence of stabilization mechanisms resulted in negligible differences in extraction efficiency between the two extractants. This study elucidates variations in extractable C/N fractions based on extractant strength, providing methodological insights for the precise assessment of soil C and N turnover and its associated eco-environmental effects.





Scenario-based forecasting of early rice heading date: Integrating effective accumulated temperature with support vector machine.

TIAN Jun, LIU Dan, WU Weixin, WU Jianming

2026, 45(8):  2787-2794.  doi:10.13292/j.1000-4890.202608.014

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To improve the forecasting accuracy of early rice heading date across diverse meteorological regimes, we developed a scenario-based model that integrates effective accumulated temperature (EAT) with support vector machine (SVM), trained on 30 years (1994-2023) of agrometeorological records from Jiangxi Province, China. The applicability and predictive performance of this model were then evaluated. Results showed that the EAT model, calibrated with 15 ℃ base temperature and adjusted for latitude, achieved high overall accuracy for early rice heading date prediction (mean absolute error (MAE)=3.1 d, accuracy=91.6%), and was particularly suitable for long leadtime forecasting under normal weather from tillering to heading. However, when this period experienced any of four abnormal weather regimes—sustained low/warm temperature, stage strong cooling/warming events, the EAT error significantly increased. The SVM model that sequentially ingested key meteorological factors, including the number of cloudy days in mid-May, temperature factors, and sunshine hours from mid-May to early June, as well as sunshine hours and cloudy (rainy) days in mid-June, effectively reduced these errors: among samples where the EAT errors were ≥3 d, SVM lowered MAE from 5.2 d to 3.3 d (a 36.5% reduction). The correction was most pronounced for prolonged low-temperature episodes, with the average forecast error being reduced from 5.7 d to 2.4 d (a 57.9% reduction). Accordingly, we proposed a scenario-adaptive strategy “EAT for normal conditions and SVM correction for abnormal conditions”, that maintains EAT’s advantage under normal weather while improving accuracy under climate extremes, providing an effective solution for precise forecasting of crop development stage under complex climatic conditions.





Construction of an ecological network based on multi-guild bird habitat suitability and identification of key ecological areas: A case study of the Xiuhe River Basin in northwestern Jiangxi Province.

FAN Shasha, GONG Xi, QIAN Yun, ZHANG Weiwei, LI Baoyong, CHEN Jie, CHEN Jiayi

2026, 45(8):  2795-2808.  doi:10.13292/j.1000-4890.202608.023

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Establishing multi-guild bird ecological networks and identifying ecological functional bottleneck areas have become crucial ecological conservation approaches to curb habitat fragmentation and biodiversity decline. We examined three guilds, including forest resident birds (FRB), forest wintering migratory birds (FWB), and aquatic wintering migratory birds (AWB), in the Xiuhe River Basin, an important overwintering habitat for migratory birds in Asia. Considering the differences in their ecological habits, we set differentiated environmental factors and resistance surface parameters suitable for different guilds. Based on the MaxEnt model and circuit theory, we conducted habitat suitability modeling for multiple species, constructed multi-guild ecological networks, and identified key ecological areas. This study aimed to achieve a high degree of matching between ecological response mechanisms and the configuration of spatial modeling parameters, and to provide theoretical support for the refined simulation of multi-species ecological networks. The results showed that: (1) There were significant spatial distribution differences between the suitable habitats and ecological source areas across the three guilds. AWB primarily inhabited Poyang Lake wetlands and adjacent waters. FWB source areas were located in the eastern Jiuling Mountains and near lake inlets. FRB source areas were widely distributed across the Jiuling Mountains, Mufu Mountains, Meiling, and the Xiuhe River lake inlet. (2) Migration pathways varied across the three guilds due to differing source distribution patterns. A total of 129 ecological corridors were identified, comprising 3 major corridors for AWB, 8 for FWB, and 19 for FRB; alongside 11 minor corridors for AWB, 18 for FWB, and 70 for FRB. (3) Six key ecological areas were identified and delineated, showing diverse spatial patterns, such as water-land ecotones and agriculture-forest mosaics. These areas were threatened by urban and agricultural expansion and fragmentation caused by transportation infrastructure. Accordingly, differentiated strategies are proposed to provide a scientific basis for biodiversity conservation and management in the Xiuhe River Basin.



Brown sugar-MFC coupling drives arsenic oxidation: Synergistic effect of bioelectrochemistry and microbial catalysis.

YAO Shuhua, ZHANG Jing, SUN Na, XU Yang, YUAN Meiting, ZHENG Yang

2026, 45(8):  2809-2816.  doi:10.13292/j.1000-4890.202608.031

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Arsenic (As), a highly toxic metalloid, is commonly found in wastewater originating from mining, metallurgical processes, and pesticide production. Due to its bioaccumulative and carcinogenic nature, arsenic poses significant risks to both human health and environmental safety. In this study, simulated brown sugar wastewater was employed as the substrate, and As(Ⅲ)-containing wastewater was used as the anolyte to construct a dual-chamber microbial fuel cell (MFC). Based on the principle of anaerobic oxidation, we examined the effects of initial As(Ⅲ) concentration on the MFC’s output voltage and arsenic and COD removal rates. The results showed that at a substrate concentration of 2 g·L^-1, the MFC maintained a stable voltage for 35 hours, demonstrating optimal electricity generation performance. Under these conditions, an initial As(Ⅲ) concentration of 1 mg·L^-1 led to removal rates of 99.5% for As(Ⅲ) and 98.6% for As(T), outperforming the 85%-95% efficiency of current commercial adsorption-based arsenic removal technologies. At an initial As(Ⅲ) concentration of 2 mg·L^-1, the system exhibited peak power density and maximum COD removal rate. Scanning electron microscopy (SEM) revealed rod-like, block-like, and flake-like deposits on the anode carbon felt. X-ray photoelectron spectroscopy (XPS) analysis showed that As(Ⅴ) constituted 71.11% of total arsenic, indicating substantial oxidation of As(Ⅲ) to As(Ⅴ), which was adsorbed onto the carbon felt. These findings confirm the feasibility and effectiveness of the MFC system in removing arsenic via anaerobic oxidation. High-throughput sequencing identified Proteobacteria, Firmicutes, Azospirillum, and Clostridium_sensu_stricto_1 as the dominant microbial groups. Based on the primciple of anaerobic oxidation, this study achieres concurrent electricity generation and removal of both organic and inorganic pollutants, offering a novel and practical approach for treating arsenic-laden wastewater.