Salt lakes account for nearly half of the world's inland water area and play an irreplaceable role as "carbon conversion and stabilization factories," making substantial contributions to the global carbon cycle. Central to this function is the transformation of dissolved organic carbon (DOC) and its accumulation into recalcitrant dissolved organic carbon (RDOC), which together underpin internal carbon processing in these systems. However, the pathways through which DOC is converted to RDOC in salt lakes, and how these pathways are shaped by salinity and microbial communities, remain poorly resolved. Here, using Yuncheng Salt Lake as a within-lake system, we combined field-based in situ characterization with long-term incubation experiments to examine how contrasting salinity regimes were associated with microbial and dissolved organic matter (DOM) variation. Higher salinity was associated with reduced bacterial and dissolved organic matter diversity, stronger deterministic bacterial assembly, and a restructured bacteria-DOM association network. Under the standardized nutrient-replete incubation conditions used here, samples from the higher-salinity regime exhibited higher biodegradable DOC, lower RDOC preservation, and greater overall DOC loss over the 100-day experimental timescale. Salinity-related differences in microbial community composition, metabolomic profiles, and dissolved organic matter characteristics were closely associated with variation in RDOC dynamics, suggesting that these carbon-processing differences were accompanied by coordinated microbial and metabolic reorganization. Together, these results provide process-relevant, condition-specific evidence that contrasting salinity regimes within Yuncheng Salt Lake were associated with differences in microbe-DOM coupling and in DOC/RDOC outcomes.

To elucidate the sources and spatial variations in organic matter in surface sediments from Lingdingyang of the Pearl River Estuary, 18 surface sediment samples were collected and analyzed for obtaining total organic carbon (TOC), total nitrogen (TN), atomic TOC/TN ratio (C/Natom), stable carbon and nitrogen isotopes (δ13C, δ15N), and glycerol dialkyl glycerol tetraethers (GDGTs). A three-endmember framework was constructed using the BIT and δ13C to constrain the sources of the organic matter. The results showed a significant positive correlation between TOC and TN, with relatively higher values in Jiaoyi Bay and western Lingdingyang, lower values in eastern Lingdingyang, and intermediate values in Shenzhen Bay. The C/Natom, δ13C, and δ15N results revealed that the sedimentary organic matter in the study area exhibits mixed-source characteristics, influenced by soil, C3 plants, and marine autochthonous organic matter. Among the subregions, Jiaoyi Bay is more strongly influenced by terrestrial inputs, while Shenzhen Bay receives relatively higher contributions from marine autochthonous organic matter. The GDGTs results showed that Jiaoyi Bay is characterized by elevated abundances of both brGDGTs and isoGDGTs, whereas isoGDGTs were also relatively enriched in Shenzhen Bay. brGDGTs exhibited a significant negative correlation with δ13C, whereas BIT showed no significant correlation with either brGDGTs or δ13C, indicating that BIT cannot be simply regarded as a unique proxy for soil input, but rather reflects the combined effects of in situ production, changes in archaeal lipids, and sedimentary preservation. The three-endmember model further revealed significant spatial variations in the sources of organic matter in surface sediments from Lingdingyang. Overall, the combined use of multiple proxies is more effective than any single proxy in revealing the sources and spatial differentiation of sedimentary organic matter in this subtropical, complex estuarine environment.

Underestimated environmental risks: Sediment stability weakening from accumulation of biomass in a eutrophic lake induced by microplastics

Grazing can adversely affect soil physicochemical properties and, despite its potential benefits on restored areas, may ultimately lead to the ecosystem degradation. Given that shrubs can partially buffer these effects, we investigate their potential as a Nature-based Solution to enhance soil nutrient storage in grazed, post-mining pastures. We assessed the combined influence of legume shrubs (plots with vs. without shrubs) and grazing (plots with vs. without a fence to prevent browsing and trampling) on soil C: N:P stoichiometry, as well as on C-N-P and exchangeable cations’ stocks in a rehabilitated coal mine. The natural colonization of legume shrubs in post-mining Mediterranean pastures maintained C: N:P stoichiometry and nutrient stocks at levels comparable to those in ungrazed areas. Specifically, the presence of shrubs increased total soil organic carbon, nitrogen, and phosphorus stocks by approximately 15%, 18%, and 12%, respectively, compared to grazed areas without shrubs. In addition, exchangeable potassium (K+) and magnesium (Mg+ 2) stocks increased by approximately 20% and 16%, respectively, under shrub canopies. In contrast, exchangeable calcium (Ca+ 2) and sodium (Na+) stocks exhibited divergent trends. In Mediterranean post-mining grasslands with low grazing pressure, native leguminous shrubs can effectively replicate the benefits of grazing exclusion by significantly enhancing soil nutrient storage. Variations in soil organic matter and structural properties accounted for 75% and 76% of the variability in nutrient stocks, respectively, underscoring their key mediating roles. These findings highlight the importance of integrating shrub management with grazing practices to support nutrient cycling and soil restoration in degraded grassland ecosystems. Legume shrubs have the same effect as livestock exclusion in storing soil nutrients. Shrubs and grazing influence soil nutrients via soil organic matter and structure. Shrubs as NbS in grazed post-mining pastures to increase soil nutrient storage. Grazing and shrub management joint strategies for soil nutrient storage in pastures. Shrubs in post-mining pastures with moderate grazing balance soil nutrient storage.

A Multi-Scale Framework for Predicting Continuous Soil Properties Using Ranked Sentinel-2 Images and Zone-Level Soil Data: From a Farm Case Study to a Regional Application

Spectroscopic and chromatographic comparison of dissolved organic matter variation to expose operational defects of municipal wastewater treatment plant resulting from carbon source dosing strategy

From Leaf to Topsoil, a Semi-quantitative Assessment of the Organic Matter Variations in Riparian Forests on a Lake Shore

The Lower Cambrian black shale in the southwestern margin of the Yangtze Block not only records the early life explosion and paleoclimate fluctuation events, but also contains abundant shale gas resources. However, due to the influence of tectonic-sedimentary differentiation, the sedimentary paleoenvironment and organic matter enrichment mechanism in this area are not completely clear, which restricts the effective exploration and development of shale gas. Based on regional drilling data and analysis of major, trace, and rare earth elements from profile samples across different facies belts, this study determines variations in marine depositional conditions and organic matter (OM) enrichment mechanisms during the Early Cambrian. The results show that: (1) In the study area, the depositional setting changes from a continental margin in the west to a continental island arc toward the east. The detritus was derived mainly from the Kangdian Oldland. The paleoclimate shifted from dry and cold to warmer and more humid conditions, with moderate chemical weathering. During the deposition of the first Member of Qiongzhusi Formation(Q1), Hydrothermal activity was intense in the eastern area and decreased gradually to the west. (2) The depositional environment of the Q1 on the southwestern margin of the Yangtze Block evolved from restricted and anoxic in the west to weakly-restricted and anoxic in the east. During the subsequent deposition of the Second member of Qiongzhusi Formation (Q2), a marine regression transformed the basin. This shift resulted in predominantly oxic conditions, more open marine circulation, and a relative increase in terrigenous sediment supply. Dysoxic conditions persisted only locally within the trough valley. (3) Primary productivity was higher in Q1 than in Q2, with the deep-water trough and hydrothermal zones providing ample nutrients for OM enrichment. (4) In Q1, OM enrichment in the western provenance-influenced area was redox-controlled (preservation model), while in the eastern upwelling zone, increased nutrient input led to productivity-dominated control (productivity model). High-quality source rocks in the trough were co-controlled by high productivity and anoxic conditions: transgression brought nutrient input and formed anoxic bottom water, jointly promoting OM enrichment. In Q2, the preservation model dominated. These findings provide a scientific basis for selecting favorable targets for shale gas exploration.

The exploration of Doggerland, the prehistoric landscape that once connected Britain to the continent, remains one of Europe’s most significant archeological challenges. This paper presents a study into the palaeolandscape and the paleoenvironmental development of Doggerland, through the geochemical analyses of a core (ELF019) taken from the southern North Sea. The thermal properties divided the core into three sedimentary zones based on the variations in organic matter and carbonate content. Organic biomarkers were used to distinguish between terrestrial and aquatic vegetation inputs, revealing alternating freshwater, terrestrial, and marine input influences. Chemostratigraphy defined six depositional zones that corresponded with the identified thermal and biomarker data. Radiocarbon dating of peat-derived humic fractions anchored the key environmental transition between freshwater and saline deposition to the Greenlandian period of the Lower Holocene (10,243–10,199 Cal BP). The integrated geochemical evidence suggests a transformation from freshwater silts, low organic content, and sandy clay deposit to saline clay marine deposit. The progressive transformation may reflect the inundation sequence that led to the final submergence of Doggerland.

The sertu purification process is an essential aspect of Islamic jurisprudence for removing najis mughallazah (severe impurities), such as contamination from dogs or pigs and their descendents. A key requirement in this process involves using water mixed with soil. However, ambiguity remains regarding the specific types and characteristics of soil that are suitable for use. This uncertainty raises practical and legal concerns, particularly as sertu is increasingly practiced in both personal and industrial contexts, and commercial soil products for sertu become more common. This study aims to evaluate the suitability of different soils for use in the sertu process based on their physical and chemical properties. Seven soil samples of varying origins and depths were analyzed using laboratory tests including particle size distribution, specific gravity, pH, organic content, X-ray diffraction (XRD), X-ray fluorescence (XRF), and cation exchange capacity (CEC). The results were assessed to determine whether differences in soil composition affect their performance and compliance with fiqh requirements. Findings indicate that while most soils share similar mineral compositions, variations in acidity, texture, and organic matter may influence their effectiveness. This study offers a scientific basis for selecting appropriate soil for sertu, supporting both technical validation and fiqh clarity in religious purification practices. The integration of geotechnical data with Islamic jurisprudence enhances the understanding and reliability of sertu, ensuring its correct implementation across various settings

In northwestern Ecuador, where more than 90% of the original forest cover has been lost, it is unknown how soil chemistry influences bat diversity. This study evaluated bat diversity, non-herbaceous plant community structure, and soil nutrients in 30 plots distributed across crops on two farms separated by 32 km. Soil analyses revealed variations in organic matter and nutrients, identifying calcium, magnesium, zinc and iron as the most influential. A total of 1662 individuals of 24 non-herbaceous plant species and 193 individuals of 16 bat species were recorded, dominated by frugivorous and nectarivorous guilds. Generalized linear mixed models showed significant relationships between bat diversity indices and soil nutrients. These elements improve tree growth, fruiting, and flowering, which increases the quality and availability of food resources for bats. In return, these mammals provide key ecosystem services such as pollination, seed dispersal, and insect control. Our findings highlight that soil chemistry indirectly regulates bat communities by influencing vegetation structure and resource availability. This integrated approach underscores the importance of soil–plant–animal interactions in tropical agricultural landscapes, offering practical guidance.

This study investigated the influence of landscape position and parent material on soil physicochemical properties and biological functioning along the Çankırı–Acıçay River toposequence. Our objectives were to (i) characterize six representative soil profiles, (ii) quantify the range and spatial variation of key hydrolytic enzyme activities (urease, phosphatase, arylsulfatase, and β-glucosidase), and (iii) evaluate the relationships between soil properties and enzymatic activity. The transect encompasses distinct lithologies: right-bank soils developed on Quaternary alluvial deposits (terraces/floodplains), while left-bank soils evolved from a complex mix including Oligo-Miocene gypsum and rock-salt strata (steep slopes). These differences resulted in classifications as Entisols, Inceptisols, and Mollisols, and distinct variations in particle-size distribution and organic matter (OM) accumulation across the profiles. Results showed that topography-driven erosion and deposition strongly controlled soil OM dynamics, which was the primary regulator of enzymatic activity. OM correlated with all enzymes, r = 0.81** to 0.89**. The old river terrace soils (depositional areas) exhibited the highest enzyme activities due to greater OM and finer texture, confirming their function as biological "hotspots". Conversely, upper-slope and gypsiferous soils displayed minimal enzymatic potential. In conclusion, variations in landscape position and parent material fundamentally alter both soil development and enzyme-mediated nutrient cycling within the semi-arid landscape of the Çankırı–Acıçay River basin.

Sources and temporal-spatial variations of sedimentary organic matter and black carbon in Zhanjiang Bay: Insights into coastal carbon burial.

Per- and polyfluoroalkyl substances (PFAS), a diverserange ofanthropogenic organic compounds, pose significant concerns to societydue to their potential harmful impacts on human health and ecosystems.While there are other methods for removing PFAS from water, adsorptionremains a viable and efficient option. The present research reportsan adsorptive nanofiber membrane prepared through electrospinningin the presence of poly­(vinyl alcohol) (PVA) and a cationic surfactant,cetyltrimethylammonium chloride (CTAC), blended solution. This modifiedPVA membrane was observed to achieve nearly 100% capture of all 10target PFAS, each at 10 μg/L in deionized water. The pseudo-second-ordermodel most accurately represented the adsorption kinetics, characterizedby rapid adsorption (within 60 s). The Toth isotherm model effectivelyfitted the isotherm data, indicating that the adsorption of PFAS ontothe membrane involved complex interactions. The hypothesized adsorptionmechanisms, including electrostatic and hydrophobic interactions,were validated through detailed adsorption kinetics, isotherms, thermodynamicanalyses, and physicochemical characterization. Remarkably, the performanceof the modified system remained unaffected by variations in solutionpH and natural organic matter, while being slightly affected by ionicstrength, with 90–100% removal effectiveness of PFAS in stormwater.This work highlights the significance of electrospun nanofiber membrane-basedadsorbents for the efficient removal of PFAS from real water.

Recent advances in wastewater treatment technologies: Innovations and new insights

This study focused on the assessment of capacity of farm soils to sequester carbon under different rice-based cropping patterns. The results of this study may be valuable for the formulation of soil and crop management for climate change mitigation in the agriculture sector in Ilocos Norte, Philippines. This study was conducted in major cultivated areas in the City of Batac, characterized by intensified and diversified cropping patterns centered around rice cultivation. A quantitative research design was employed to determine the different cropping patterns and their influence on soil organic carbon (SOC). The dominant cropping patterns observed in Batac City was rice, followed by any of the following crops; corn, shallot, eggplant, rice, tomato, pepper, garlic and tobacco. These cropping patterns are assumed to have an influence in soil pH, organic matter (OM), % carbon, phosphorus (P), potassium (K), bulk density, soil texture, moisture content, and soil carbon stock (SOC). Results showed that soil organic matter content in various cropping patterns was proportional to the soil carbon stock in the soil. The analysis of variance between cropping patterns exhibited high variability in OM and SOC with an F-value >1. Rice-tobacco exhibited the highest carbon stock (1.80%), while rice-garlic (0.63%) and rice-corn (0.60%) had the lowest. Understanding the influence of crop biomass and management through this study can be beneficial in the design of informed decision-making strategies and advocacy on cropping pattern management, which can be disseminated to farmers to enhance the carbon sequestration potential of agricultural lands.

Methanotrophic communities play a vital role in regulating methane fluxes in wetland ecosystems. This study examined the composition and environmental drivers of methanotrophs in estuarine and nearshore wetlands of the Qinghai Lake basin. Soil samples from six sites across three tributaries showed clear spatial and vertical variation in organic matter, nitrogen forms, and salinity. The Heima River estuarine wetland exhibited the highest methanotrophic diversity and functional potential. Dominant genera included Methylobacter, Methylosinus, and Methylocystis, with site-specific distributions. Redundancy analysis identified soil organic matter, nitrate nitrogen, pH, and electrical conductivity as key factors shaping community structure. These findings reveal how water-salt interactions and nutrient status influence methane-oxidizing microbes, offering insights into carbon cycling dynamics in high-altitude wetlands and supporting ecological restoration efforts in plateau regions.

Variations in organic matter and microbial community responses to microplastic stress at different soil depths in landfills

This paper presents an investigation of the isotopic characteristics of organic matter in Upper TriassicJurassic sediments of the West Siberian Basin, which are crucial for understanding the processes of oil and gas formation in the region. Based on detailed isotopic studies of bitumoids, a pattern of isotopic characteristic changes is demonstrated, driven by the influence of facies conditions of sedimentation. The aim of the study was to identify and systematize the regularities of carbon isotope distribution in autochthonous organic matter to create a genetic picture of its formation in various paleogeographic settings of the Jurassic period. Isotope-fractionation analysis of bitumoids allowed us to identify five groups, reflecting the link between the isotopic composition of organic matter and sedimentation conditions within the Frolovsko-Shaimsky, Yamalo-Gydansky, and Urengoy facies regions. The obtained results are of great importance for regional geology and petroleum geology, contributing to the optimization of hydrocarbon exploration and development strategies in the West Siberian Basin and providing new tools for assessing the hydrocarbon potential of sedimentary basins in general.

Hyperspectral imaging of lake sediment cores offers a promising analytical method being both high-resolution and non-destructive. In this study, we investigate the potential of an industry-standard hyperspectral (VNIR) camera combined with a custom developed software package to provide indirect data on past changes in sediment accumulation conditions of a mid-elevation lake in the Caucasus Mountains. The software allows for automated core fragment stitching, crack removal and spectral analysis. We introduce the technique of wavelength correlation mapping as a tool to trace within-core variations of spectral properties (i.e. absorption features). The absorption feature around 670 nm wavelength marks a characteristic distinction between organic-rich and organic-poor sections of the studied sediment core. This part of the spectrum corresponds to absorption of electromagnetic radiation by chlorophyll a , a pigment ubiquitous in photosynthetic organisms. In this study, we use the techniques of relative absorption band depth (RABD) and area (RABA) with various spectral spans to calculate and compare the 670 nm derived spectral indices. The selected RABD 660;670 index serves as a high-resolution (229 μm/px) proxy for downcore variations of autochthonous organic matter and provides the reconstruction of lake productivity for the period 3000–1000 BP with subannual resolution. The results are supported with independent biogenic proxies – total organic carbon, loss-on-ignition and concentration of bromine in the sediment.