Search Results (1,380)

As vital carbon pools within terrestrial ecosystems, wetlands store sediment organic carbon (SOC), a process influenced by plant communities, seasonal variations, and wetland types. Microbial communities, fundamental to wetland ecosystems, are hypothesized to regulate carbon storage. We investigated sediment microbial communities and carbon storage in different seasonal and plant conditions in two types of wetlands. Sediment organic carbon, the associated environmental factors, and microbial community characteristics were detected to explore the impacts of seasons and plants on SOC. Plants and seasons significantly influenced the content of SOC in constructed wetland, while only altered the content of dissolved organic carbon (DOC) in river wetland. In river wetland, plants increased the microbial function of Amino Acid Metabolism through the input of exogenous dissolved organic carbon (DOC) and the effect on moisture content. The functional traits of Carbohydrate Metabolism in sediment were higher in river wetland than that in constructed wetland. Our results indicated that plants and seasons influenced SOC in wetlands through their effects on sediment microbial community and function. Compared with the river wetland, the constructed wetland had more stable microbial communities and might be easier to fix organic carbon from plants. This study highlights the importance of the carbon sequestration potential of constructed wetlands due to the stable microbial communities. Full article

Catechol (benzene-1,2-diol) is a highly versatile chemical motif that plays a central role in both terrestrial and marine systems, where its reactivity is governed by a combination of enzymatic oxidation and non-enzymatic interactions. This review examines the diverse enzymatic pathways responsible for catechol oxidation, including polyphenol oxidases, laccases, peroxidases, and microbial dioxygenases, and highlights how these conserved systems are adapted to distinct ecological functions such as plant defense, carbon cycling, bioadhesion, and material formation. A key focus is placed on the non-enzymatic formation of boron–catechol complexes, which can significantly modulate catechol reactivity. These complexes, formed through reversible interactions between boron species and the 1,2-diol group, can act as inhibitors of catechol oxidation by limiting substrate availability and altering redox behavior. Importantly, the extent of this inhibition is strongly dependent on pH, which governs both the speciation of boron (e.g., boric acid vs. borate) and the stability of borate esters, as well as the activity of oxidative enzymes. In terrestrial systems, variable pH conditions and soil chemistry influence the balance between oxidation, complexation, and degradation, whereas in marine environments, relatively stable and slightly alkaline conditions favor distinct modes of regulation. By integrating enzymatic and non-enzymatic perspectives, this review underscores the importance of boron–catechol interactions as a previously underappreciated control on catechol oxidation across ecosystems, with implications for biogeochemical cycling and the design of bioinspired materials. Full article

This study aims to resolve the genetic origin of crude oils accumulated in the D Subsag and to assess the potential cross-sag hydrocarbon migration from the adjacent Haizhong Sag. The D Subsag, situated on the western margin of the Weixinan Sag in the Beibuwan Basin, is a significant petroleum province with proven reserves exceeding 10 million tons in the Weizhou Oilfield. However, the origin of these oils and the contribution from the Haizhong Sag source kitchen remain poorly constrained, hindering accurate resource assessment. To address this, we integrated organic geochemical analyses of nine source rock samples from the Haizhong Sag (Well H1) and eight crude oil samples from the D Subsag reservoirs. Bulk geochemical and biomarker signatures reveal distinct organic facies within the Paleogene succession. Type III kerogen, characterized by terrigenous higher plant input (high C₁₉₊₂₀ tricyclic terpanes and C₂₉ regular steranes, Pr/Ph > 2.5) deposited under oxic freshwater conditions, dominates source rocks from the third member of the Weizhou Formation (EWZ₃). In contrast, the second and third members of the Liushagang Formation (Els₂ and Els₃) contain mixed Type II₂-III kerogen with elevated contributions from lacustrine algae and aquatic organisms (elevated C₂₃ tricyclic terpanes and C₂₇ regular steranes). Thermal maturity assessment (with T_max of 436 to 448 °C) confirms that all source intervals are within the oil generation window. Two genetically distinct oil groups are identified in the EWZ₃ reservoirs. Group 1 oils (Well W4) exhibit a lacustrine algal signature (C₂₇/C₂₉ sterane > 1.15; low Pr/Ph 1.54–1.68) that does not correlate with the analyzed Haizhong Sag source rocks, suggesting localized, intra-sag source contributions. In contrast, Group 2 oils (Wells W6 and W6-2) display strong geochemical affinities with the Els₂ and Els₃ source rocks, evidenced by mixed terrestrial/aquatic signatures (∑nC₂₁⁻/∑nC₂₂⁺ < 1.0). These findings confirm that fault systems acted as conduits for long-distance migration from the Haizhong Sag, while also highlighting a previously unrecognized contribution from local source intervals. This refined petroleum system model provides critical constraints for delineating remaining hydrocarbon potential and reducing exploration risk in the Beibuwan Basin. Full article

The efficiency with which solanaceous crops are pollinated is determined by pollinator behavioral preferences. Although Bombus terrestris typically outperforms Apis mellifera in this respect, the chemo-ecological mechanisms underlying their divergent olfactory responses remain insufficiently determined. We combined behavioral assays, gas chromatography–mass spectrometry, and electroantennogram recordings to compare the responses of these bee species to the volatile organic compounds (VOCs) emitted by tomato, pepper, and eggplant flowers. Whereas B. terrestris showed a strong foraging preference for all three crop plants, A. mellifera displayed distinct avoidance. Chemical analyses identified 82, 63, and 60 VOCs in tomato, pepper, and eggplant flowers, respectively. Among the 14 VOCs commonly emitted by all three crops, linalool, nerol, (E,E)-2,4-decadienal, 2-hexenal, tridecanal, and (E,Z)-2,6-nonadienal elicited significantly different electrophysiological responses in the two bee species, and are, thus, considered key compounds mediating their behavioral differences. Moreover, in behavioral assays, A. mellifera and B. terrestris showed significantly different responses to four concentration levels of linalool, nerol, (E,E)-2,4-decadienal, and tridecanal. This study elucidates the plant–pollinator olfactory interactions that contribute to determining the different foraging behaviors of two bee species in pollinating solanaceous crops, thereby providing a theoretical basis for optimizing pollinator attraction strategies. Full article

Low temperature severely constrains the growth and ecological application of submerged macrophytes in aquatic ecosystem restoration. Although brassinolide (BR) has been shown to alleviate abiotic stress in terrestrial plants, its role in submerged macrophytes remains poorly understood. This study investigated the effects of different BR concentrations (0, 0.05, 0.1, and 0.5 mg L⁻¹) on growth, photosynthesis, antioxidant defense, and osmotic adjustment in Hydrilla verticillata under low-temperature stress (2 °C) over 15 days. Exogenous BR significantly alleviated low-temperature-induced damage in H. verticillata in a concentration-dependent manner. Among all treatments, 0.05 mg L⁻¹ BR showed the strongest overall effect, increasing fresh weight, dry weight, and plant height by 16.22%, 22.67%, and 9.52%, respectively, compared with the control. It also promoted photosynthetic performance, with Fv/Fm and Y(II) increasing by 251.93% and 262.83%, respectively, on day 10, and enhanced stress resistance, as reflected by a 32.44% increase in SOD activity and a 112.59% increase in soluble sugar content on day 15. In contrast, higher BR concentrations (0.1 and 0.5 mg L⁻¹) were less effective overall. Membership function analysis ranked the treatments as 0.05 mg L⁻¹ (0.95) > 0.1 mg L⁻¹ (0.47) > 0.5 mg L⁻¹ (0.19) > 0 mg L⁻¹ (0.09). These results indicate that BR enhances low-temperature tolerance in H. verticillata through coordinated regulation of photosynthetic performance, antioxidant defense, and osmotic adjustment, providing a physiological basis for its application in submerged macrophyte restoration under low-temperature conditions. Full article

This systematic review was conducted and reported according to the PRISMA 2020 statement to synthesize evidence published between January 2020 and January 2025 on food-derived antihypertensive peptides, with emphasis on mechanisms of action, molecular stability, bioavailability, and functional food applications. PubMed, Scopus, and Web of Science were searched using combined terms related to bioactive or ACE-inhibitory peptides, stability or bioavailability, and alternative protein sources. Original peer-reviewed studies in English evaluating antihypertensive or ACE-inhibitory peptides from plant, marine, insect, fungal, dairy, or terrestrial animal matrices were considered eligible when they reported experimental evidence on activity, stability, transport, or in vivo efficacy. Three reviewers independently screened records and extracted data. A total of 177 studies were included. Plant and marine matrices accounted for approximately 72% of the evidence base, with a strong focus on low-molecular-weight peptides (<3 kDa) and multistage validation pipelines integrating in silico screening, in vitro enzymatic assays, Caco-2 transport models, ex vivo assays, and spontaneously hypertensive rat studies. Overall, the evidence supports the antihypertensive potential of selected food-derived peptides, particularly through ACE inhibition and related vascular mechanisms. Encapsulation and advanced delivery approaches improved peptide stability and bioavailability in several studies. Food-derived antihypertensive peptides represent promising candidates for functional foods and nutraceuticals; however, greater methodological standardization, formal risk-of-bias assessment in primary studies, and well-designed human trials remain necessary to strengthen translation into practice. Full article

Monacha cartusiana (O. F. Müller, 1774), native to the Mediterranean region and Europe, is a terrestrial gastropod recognized as a highly destructive agricultural pest that causes significant damage to crop plants, fruit trees, vegetables, ornamentals, and natural ecosystems. Despite its broad geographic distribution, the evolutionary history and phylogeographic relationships of M. cartusiana populations remain globally unexplored. This study reports the first molecularly confirmed record of M. cartusiana in Pakistan and investigates its genetic diversity and phylogeographic structure within a global context using mitochondrial markers. After morphological identification, genomic DNA was extracted from collected specimens using the CTAB method, followed by amplification and sequencing of the mitochondrial COI and 16S rRNA genes. The resulting sequences were subsequently analyzed using DnaSP and PopART software to estimate genetic diversity, perform neutrality tests, and construct haplotype networks. Published sequences of M. cartusiana retrieved from GenBank were incorporated to provide a global comparative framework. The COI dataset (555 bp) revealed 52 haplotypes, whereas the 16S rRNA dataset (269 bp) identified 14 haplotypes across global populations. High haplotype diversity (Hd = 0.946 for COI; Hd = 0.831 for 16S rRNA) and moderate nucleotide diversity (π = 0.010 for COI; π = 0.01253 for 16S rRNA) indicated substantial genetic variability within the species. Neutrality tests produced negative and insignificant values for Tajima’s D for COI and significant values for 16S rRNA (−1.428 for COI; −0.20586 for 16S rRNA) and Fu’s Fs (−29.776 for COI; −1.263 for 16S rRNA), suggesting historical population expansion. Phylogenetic reconstruction and haplotype network analyses identified two major clades (Clade A and Clade B), reflecting genetic relationships among populations from different geographic regions. AMOVA based on COI and 16S rRNA sequences revealed significant population structuring, with 29.98–51.30% of the total genetic variation occurring among populations and high fixation indices (FST = 0.299–0.51398, p = 0.001), indicating pronounced genetic differentiation and restricted gene flow. Pairwise FST analyses indicated that the Pakistani population is most closely related to populations from Italy and Central Europe, suggesting a closer genetic affinity with Southern or Central European populations. However, FST alone does not allow definitive inference of introduction directionality, and additional analyses would be required to robustly identify the source population. Overall, this study provides the first comprehensive molecular and phylogeographic assessment of the M. cartusiana species from Pakistan within a global context. These findings contribute important baseline data for understanding the evolutionary dynamics, dispersal history, and population connectivity of this economically important pest species. The pronounced genetic differentiation among populations and the suggested genetic affinity of the Pakistani population with European lineages have direct implications for biosecurity monitoring, invasion pathway tracing, and targeted pest management strategies. Future research integrating nuclear markers with the mitochondrial data presented here will be essential for a more complete understanding of gene flow and local adaptation in this species. Full article

The extensive use of agrochemicals and plastic materials has led to the accumulation of persistent pollutants in agricultural soils, raising concerns about agroecosystems through posing potential risks to soil and environmental health. This review synthesizes recent knowledge on these pollutant sources, including their distribution, fate, transformation pathways, and detection methods, as well as their impacts on soil physicochemical properties, microbial populations, plants, and ecosystems. Existing findings indicate that agrochemicals and micro-nano plastics (MPs-NPs) can significantly impede the stability of soil aggregation, increase soil water holding capacity (WHC) and porosity, reduce bulk density and infiltration, alter soil structure, and affect soil pH, cation exchange capacity (CEC), electrical conductivity (EC), and nutrient retention capacity. Moreover, exposure to these pollutants alters soil microbial communities, enzymatic activity, nitrification and denitrification processes, and arbuscular mycorrhizal fungi (AMF), thereby affecting carbon pools and fluxes as well as nutrient cycling. However, the magnitude and direction of these effects are strongly influenced by soil type, pollutant class, concentration, and physicochemical properties. Furthermore, terrestrial and aquatic ecosystems are negatively affected due to the presence of such persistent pollutants by impairing their physiological processes. Despite these findings, mechanistic understanding remains limited due to a lack of long-term field investigation and proper detection methods, particularly regarding NPs. A comprehensive understanding of agrochemical and MP-NP interactions is essential for developing sustainable soil management strategies and agroecosystems. Future studies should address the development of standardized NP detection methods and the conducting of long-term field studies to elucidate MP-NP and agrochemical interactions, soil impacts, and crop uptake mechanisms. Full article

Snail mucus is increasingly investigated as a biologically compatible source of multifunctional biomolecules for pharmaceutical and dermatological use. However, the chemical profile and biological activities of mucus from the Moroccan endemic terrestrial snail Otala tingitana remain poorly characterized. In addition, the influence of heliciculture diet on the composition and functional properties of the mucus remains unclear. Here, O. tingitana was reared for 140 days under controlled conditions and fed a basal flour diet or the same diet supplemented with 3% Rosmarinus officinalis, Origanum compactum, or Thymus zygis subsp. zygis. Mucus from wild snails was included for comparison. Mucus samples were chemically profiled by GC–MS and evaluated for antibacterial activity, antioxidant capacity, wound-healing efficacy in mice, and histological anti-inflammatory effects, and evaluated semi-quantitatively based on the degree of inflammatory cell infiltration. GC–MS identified 13 compounds and demonstrated clear diet-dependent shifts in dominant components. All mucus samples exhibited broad-spectrum antibacterial activity against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella Typhimurium (inhibition zones 10.31–14.30 mm; MIC 120–240 µg/mL), with predominantly bactericidal profiles (MBC/MIC < 4) and significantly enhanced activity in plant-supplemented groups (p < 0.05). Antioxidant performance improved markedly with medicinal-plant supplementation, reaching low IC₅₀ values (best ≈ 1.18 mg/mL) compared with basal-diet mucus. In vivo, topical application accelerated wound closure, achieving complete healing in <21 days, versus 28 days in untreated controls. In addition, histological assessment showed faster resolution of inflammatory cell infiltration in treated groups. Collectively, these findings provide the first integrated evidence that O. tingitana mucus possesses antibacterial, antioxidant, wound-healing, and anti-inflammatory activities, and that heliciculture diet is a practical lever to optimize its bioactive profile. Further studies should prioritize standardized manufacturing, contaminant control, and safety/toxicology assessment before translational development. Full article

Pasture plants can contribute to ruminant nutrition and may, depending on composition, influence rumen fermentation and methane production. This study evaluated the nutritional composition, bioactive compounds, and methane production potential of 32 terrestrial plant species commonly foraged by goats in Malta. Dried plant samples were analysed for proximate composition using near-infrared spectroscopy, total polyphenols using the Folin–Ciocalteu assay, antioxidant activity using the DPPH assay, and methane production using an in vitro rumen fermentation system incubated for 48 h, with rumen fluid pooled from three goats (analyses performed in triplicate). Crude protein ranged from 1.16 to 31.97% DM, neutral detergent fibre from 12.29 to 48.89%, and ash from 9.69 to 17.20% across species. Total polyphenolic content varied from 0.07 to 1.30% (w/w), while antioxidant activity (IC₅₀) ranged from 0.37 to 55.9 mg/mL. Methane production after 48 h ranged from 30.39 to 198.26 L CH₄ kg⁻¹, indicating variation in fermentation characteristics among species. These results indicate that Rumex bucephalophorus and Urtica pilulifera demonstrated relatively high protein or bioactive values and comparatively lower in vitro methane-related parameters under the conditions tested. Full article

Microplastic (MP) and nanoplastic (NP) pollution has emerged as a pervasive and still insufficiently quantified pressure on terrestrial ecosystems, yet its consequences for wild herbivores remain incompletely understood. As key links between primary producers and higher trophic levels, wild herbivores occupy a critical ecological position and may serve both as exposed receptors and as biological vectors of plastic contamination. This manuscript presents a narrative review that synthesizes recent advances in understanding the physiological, behavioural, and ecological implications of MP and/or NP exposure in free-ranging herbivorous mammals, integrating evidence from field surveys, experimental studies, ecological modelling, and supportive mechanistic findings from livestock and experimental mammalian systems. Available evidence indicates that MPs and NPs are consistently detected in wild herbivores from both human-modified and protected landscapes, demonstrating widespread terrestrial exposure. Reported biological effects include oxidative stress, digestive dysfunction, inflammatory and immune responses, altered gut microbial communities, impaired nutrient assimilation, and organ-level damage, although much of the mechanistic evidence derives from controlled laboratory or livestock-based studies rather than direct wildlife investigations. Behavioural responses remain comparatively underexplored, particularly in large-bodied herbivores, with limited evidence for altered foraging, habitat use, and stress-related behaviours. At the ecosystem level, emerging studies suggest that herbivores may contribute to the landscape-scale redistribution of MPs and NPs through movement and faecal deposition, with potential downstream effects on soil processes, nutrient cycling, and plant–herbivore interactions. However, the current evidence base is constrained by major methodological and conceptual limitations, including the lack of standardized detection and reporting protocols, limited ecological realism in exposure studies, taxonomic and geographic biases, and poor resolution of long-term population-level and food-web consequences. Overall, the available literature indicates that MP and NP pollution represent a multifaceted and emerging risk to wild herbivores and the ecosystems they inhabit. Future research should prioritize standardized contamination-controlled monitoring, non-invasive faecal surveillance, ecologically realistic chronic exposure studies, and integrated conservation frameworks that recognize wild herbivores as sentinel species for terrestrial plastic pollution. Full article

Grasslands are key terrestrial ecosystems in which root dynamics regulate soil carbon and nutrient cycling. Although grazing constitutes the predominant land use practice in grassland ecosystems, its impacts on root dynamics remain inadequately elucidated, particularly across a gradient of grazing intensities. In this two-year field experiment, an improved root window method was applied to investigate the effects of four grazing intensities (no grazing, light grazing, moderate grazing, heavy grazing) on root production, root mortality, root standing crop, root turnover, and root lifespan in the saline–alkaline grassland in northern China. The results showed that root production and root mortality exhibited pronounced seasonal dynamics, with peaks in June and August for root production and in September for root mortality. These seasonal patterns were primarily driven by precipitation and were not significantly altered by grazing intensity. Moderate grazing significantly increased root production by 51.2% through changes in soil bulk density and selective livestock grazing, supporting the intermediate disturbance hypothesis. Root turnover was predominantly shaped by plant community composition and interannual precipitation, as opposed to grazing intensity. Overall, these findings indicate that moderate grazing promotes root growth, providing important insights into the sustainable utilization of saline–alkali grassland resources. In other words, appropriate measures must be taken to effectively manage grazing activities in the fragile saline–alkaline grasslands of northern China. Full article

This study conducts a cradle-to-gate Environmental Life Cycle Assessment (E-LCA) of tea production in Sri Lanka, comparing smallholder and estate-owned plantations processed by Orthodox and Crush–Tear–Curl (CTC) methods. Unlike most tea LCA studies that treat cultivation as a single undifferentiated phase, this work explicitly incorporates the perennial nature of tea by using a modular life cycle framework that separates the agronomic stages alongside factory processing up to the packed-tea gate. This approach allows a more precise allocation of long-term environmental burdens over the entire productive lifespan of the tea plant, addressing a methodological gap in the literature. Four production scenarios were evaluated: Smallholder-Orthodox, Smallholder-CTC, Estate-Orthodox, and Estate-CTC, with the functional unit set to 1 tonne of processed tea. Primary data were gathered through structured surveys of 30 plantations (25 smallholders, 5 estates) and 5 tea factories, supplemented by secondary data from Ecoinvent v3.11 and national statistics. The CML-IA Baseline method in SimaPro v9.5 was applied to characterize impacts across eight impact categories: global warming potential (GWP), abiotic element depletion, fossil fuel depletion, acidification, human toxicity, terrestrial ecotoxicity, freshwater ecotoxicity, and eutrophication. Results indicate that Smallholder-Orthodox systems have the highest GWP (3304 kg CO₂ eq per tonne), whereas Estate-CTC systems show a lower GWP (2894.87 kg CO₂ eq). Acidification potential ranges from 47.21 kg SO₂ eq for Smallholder-Orthodox to 41.25 kg SO₂ eq for Estate-CTC. Overall, the findings suggest that the scale of plantation management has a greater impact on environmental performance than processing technology, highlighting the need to focus sustainable practices on the cultivation stage, exactly where the perennial crop modeling approach used here provides the greatest analytical benefit. Full article

Phosphorus (P) limitation is prevalent in terrestrial ecosystems. Plants can improve soil P availability through the exudation of organic acids and symbiotic interactions with microorganisms. However, associations between different plant functional groups and phosphorus cycling in P limited karst ecosystems remain poorly understood. To investigate this, the exudation rates of oxalic, citric and acetic acids from fine roots, the contents of carbon, nitrogen, and P in leaves and fine roots, and the contents of oxalic, citric and acetic acids, total P, available P (AP), and microbial biomass P in rhizosphere soils were measured across different plant functional groups in a karst ecosystem in southwestern China. Additionally, the activities of acid and alkaline phosphatases were also analyzed, as well as the relative abundance, community structure, diversity, and co-occurrence network patterns of arbuscular mycorrhizal fungi (AMF) and alkaline phosphatase-encoding (phoD) gene-harboring bacteria. The results showed that both the exudation rates and the contents of organic acids and AP were highest in the tree group, followed by the shrub and grass groups. The AP content of the legume group was significantly higher than that of the non-legume group. The exudation rates of oxalic acid were significantly greater than those of citric and acetic acids. AMF diversities were highest in the shrub and legume groups. The diversities of phoD-harboring bacteria decreased from the tree group to the shrub group and then to the grass group, yet there were no significant differences between the legume and non-legume groups. The communities of both AMF and phoD-harboring bacteria exhibited significant differences among these plant functional groups. The prevalent genera of phoD-harboring bacteria across all groups were Pseudomonas and Halomonas, with Halomonas being particularly prevalent in the legume group. The AMF community was dominated by Glomus, which attained its highest relative abundance in the tree and legume groups. Furthermore, the increased exudation rate and content of oxalic acid were associated with higher relative abundances of Glomus in AMF and Pseudomonas and Bacillus among phoD-harboring bacteria. Structural Equation Model (SEM) analysis demonstrated that plant-exuded organic acids, especially oxalic acid, were positively associated with P availability indirectly through their linkages with the diversity and abundance of AMF and phoD-harboring bacteria. The crucial role of oxalic acid was particularly prominent in the tree and legume groups. Our findings suggest that screening AMF and phoD-harboring bacteria with highly efficient P transformation activity and inoculating them into the rhizosphere of plants with high oxalic acid exudation could help improve plant resilience to P limitation and support sustainable restoration in karst ecosystems. Full article

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/N_atom), 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/N_atom, 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. Full article