Search Results (125)

Tropical lake ecosystems are vulnerable to degradation due to climate change and anthropogenic pressure. These dual pressures lead to ecological change and alterations in aquatic parameters, including chlorophyll-a (Chl-a). Lake Poso is the third-largest lake in Indonesia; Chl-a variability and phenology in this tropical lake remain understudied due to brief observational records. This study characterizes the spatiotemporal variability and phenology of Chl-a in Lake Poso, Indonesia, over two decades (2003–2025) to establish a multi-decadal baseline and detect early indications of increasing phytoplankton biomass. Chl-a was derived from combined Terra and Aqua MODIS observations processed in Google Earth Engine, followed by trend, phenological, and spatial analyses. Results reveal a significant increase in annual Chl-a and a general upward tendency across the study period. Climatological reconstruction identifies a distinct bimodal phenology, with a primary peak in December and a secondary peak in April. Interannual trends show no significant shift in Start of Season timing; however, primary peak magnitudes tend to increase (+0.079 mg m⁻³ yr⁻¹), largely influenced by extreme episodic anomalies. Spatial analysis reveals heterogeneous increases in Chl-a, particularly in the central and northern zones. These findings suggest a possible early trajectory toward higher phytoplankton biomass and establish the first satellite-derived multi-decadal Chl-a baseline for Lake Poso. Full article

Lake Baikal is a UNESCO World Heritage Site and the largest freshwater reservoir on the planet. It is located in the center of Eurasia, in an industrially developing region—Eastern Siberia. Although a regulatory and legal framework exists, quantitative estimates of the pathways of pollutant transport from industrial sources to the lake water area remain insufficiently studied, particularly in the context of seasonal dynamics and the influence of developing industrial sectors. In the present work, a quantitative analysis of the direct atmospheric transport of pollutants from three groups of stationary sources (the Irkutsk agglomeration, the Republic of Buryatia, and the oil-and-gas production areas of Irkutsk Oblast) to the lake surface was carried out for the first time using the HYSPLIT model for the period 2005–2025. About 4.7 million forward trajectories were computed at three heights (250, 500, 1000 m AGL) for each group of sources. It was established that conditions favorable for the transport of impurities to the lake occur in more than half of the cases. However, the spatial distribution of the impact on the Baikal air basin is heterogeneous: the Irkutsk agglomeration accounts for 67.5% of the “hits” (the main contribution being to the air basin of the Southern Basin), the Republic of Buryatia 18.8% (to the Central Basin), and the oil-and-gas areas 19.9% (to the Northern Basin). On the basis of a multifactor analysis, a combined Potential Impact (PI) index was developed that makes it possible to rank regional sources by the degree of their impact on the lake ecosystem, taking into account the emission volume, the probability of delivery, the residence time, and the height of trajectory passage. The results form a scientific basis for optimizing the spatial placement of environmental monitoring networks and for preliminary zoning of environmental risk assessment over the Lake Baikal water area. Ultimately, this study contributes to the sustainable management of the Baikal Natural Territory by providing actionable insights for balancing regional industrial growth with the long-term ecological preservation of the planet’s largest freshwater reservoir. Full article

Cyanobacterial harmful algal blooms (cHABs) pose increasing ecological and public health risks in shallow lakes subject to nutrient enrichment and climate change. This research describes and evaluates a three-dimensional hydrodynamic ecological modeling framework for Fairy Lake, Ontario, using MIKE 3 FM coupled with ECO Lab to simulate lake circulation, thermal structure, nutrient dynamics, and cyanobacteria (PC3) concentrations, with model calibration using 2022 data observations and validation using 2023 data. Hydrodynamic performance showed moderate agreement for lake levels (NSE 0.47–0.52) and strong predictive capability for water temperature (NSE up to 0.96 across depths). Nutrient simulations reproduced seasonal nitrate and phosphate trends, with sediment parameter adjustments to stabilize internal loading dynamics. Cyanobacteria simulations captured seasonal bloom timing and spatial variability between inflow and central basin zones during the calibration and validation periods. The results demonstrate that integrated 3D hydrodynamic ecological modeling reproduces seasonal bloom dynamics in shallow polymictic lakes employing calibrated models and subsequent data, to predict sediment nutrient processes and periodic reassessments. As a result, this framework provides a quantitative basis for evaluating bloom behavior and the ability to predict management scenarios able to test changing climatic and nutrient conditions. Full article

Shallow lakes are vulnerable to multiple anthropogenic stressors. However, the spatial responses of benthic ecosystems to these composite disturbances and the underlying mechanisms driving them remain poorly understood. Nansi Lake is a strategic water-regulating reservoir of the Eastern Route of the South-to-North Water Transfers. It has long been subjected to multiple human activities, and its aquatic ecological environment exhibits pronounced spatial heterogeneity. A systematic assessment is thus needed to evaluate the spatial distribution patterns of surface-sediment diatom communities and their trophic response characteristics. This study integrates the Trophic Diatom Index (TDI) with multivariate statistical approaches. It analyzes the spatial distribution and driving factors of surface-sediment diatom assemblages based on diatom and water quality data from 62 sampling sites. The results reveal three distinct community zones across the lake. The first is a high-disturbance zone dominated by hydraulic regulation and mining activities. In this zone, Stephanodiscus parvus Stoermer & Håkansson is the absolute dominant species, indicating a clear eutrophic status. The second is a hydrochemically stable zone dominated by Achnanthidium minutissimum (Kützing) Czarnecki, exhibiting relatively high community integrity. The third is a vast central open-water zone characterized by the dominance of Pseudostaurosira brevistriata (Grunow) Williams & Round, representing a mesotrophic transitional state. Partial redundancy analysis (pRDA) shows that multiple explanatory variables jointly explain 28.91% of the community variation. The independent explanatory powers of anthropogenic variables (9.12%) and environmental factors (7.94%) are both higher than that of pure spatial dispersal processes (0.35%). Redundancy Analysis (RDA) indicates that different types of human activities—such as reservoir regulation, coal mining, and estuarine inflows—may influence the spatial distribution patterns of surface-sediment diatoms. They do so by jointly driving variations in lake trophic status and the ionic environment, particularly Mg²⁺ and SO₄²⁻. This study provides a scientific basis for the water resource management of shallow lakes subject to anthropogenic impacts. Full article

Ecological network resilience is an important indicator for evaluating whether regional ecosystems can maintain structural connectivity and functional stability under external disturbance. However, long-term changes in ecological network structure and robustness in the Poyang Lake Eco-economic Zone remain insufficiently understood. Based on land-use data from 1990, 2000, 2010, and 2020, this study integrated Morphological Spatial Pattern Analysis (MSPA), landscape connectivity assessment, the MCR model, complex network analysis, and robustness simulations to evaluate the spatio-temporal evolution of ecological network resilience in the Poyang Lake Eco-economic Zone. The results showed that the area of selected ecological sources in the study area decreased from 39.97% in 1990 to 33.14% in 2020, indicating continuous source-area shrinkage and habitat fragmentation. The ecological resistance surface showed increasing spatial heterogeneity, with relatively low resistance in mountain and lakeside wetland areas and high resistance in the central plain areas affected by agricultural and construction-land expansion. Topological analysis showed that network density increased from 0.10 to 0.15, average path length decreased from 3.04 to 2.53, and network efficiency increased from 0.34 to 0.45, suggesting enhanced local connectivity and transmission efficiency. However, the largest connected component decreased from 37 to 26, indicating a decline in regional-scale connectivity and an increasing risk of network fragmentation. Robustness simulations further showed that the network was relatively tolerant to random disturbance but highly sensitive to the priority failure of key nodes and corridors. Overall, the ecological network evolved from relatively continuous connectivity toward local clustering and residual trunk corridors. These findings suggest that ecological restoration in the Poyang Lake Eco-economic Zone should prioritize major ecological sources, cross-regional corridors, stepping-stone habitats, and critical linkage areas to improve network-level resilience. Full article

Wild waterfowl constitute the primary natural reservoir of influenza A viruses, and wetlands at the convergence of major migratory flyways serve as critical hubs for viral genetic exchange. Baikal Siberia, situated at the intersection of the East African–West Asian, Central Asian, and East Asian–Australasian flyways, represents a unique yet understudied region in this context. Here we report the results of long-term virological surveillance of wild birds in the Lake Baikal basin conducted between 2018 and 2024. A total of 1036 cloacal swab samples from 28 bird species were screened, yielding 42 influenza A virus isolates belonging to 12 HA/NA subtype combinations: H1N1, H3N1, H3N2, H3N5, H3N6, H3N8, H4N6, H6N1, H6N2, H6N3, H6N8, and H12N5. Among the detected subtypes, H6 viruses—identified with four distinct neuraminidase combinations (N1, N2, N3, N8)—are of particular public health relevance owing to their documented capacity for dual-receptor binding and potential for zoonotic transmission to mammals, including humans. Full-genome sequencing followed by cluster analysis of internal gene segments identified 16 distinct segment constellations, indicating extensive reassortment. BLAST searches against the GISAID database revealed closest genetic relatives in Mongolia, South Korea, Japan, China, and Western Siberia, with more distant links to Bangladesh, Europe, and a possible intercontinental connection via the Pacific flyway. Maximum-likelihood phylogenetic analysis of the HA and NA segments confirmed that all isolates belong to the Eurasian genetic lineage, yet they are distributed across multiple clades rather than forming a single monophyletic group, reflecting the role of Buryatia as a mixing zone for genetically diverse viral populations. These findings substantially expand the understanding of influenza A virus ecology in the Lake Baikal basin and underscore the importance of continued surveillance at this key migratory crossroads in Northern Asia. Full article

Wetlands sustained some of the most exceptionally dynamic human–environment relationships in past societies. Tracing their presence and ecological characteristics in antiquity requires integrated recovery strategies that link excavation, systematic sampling, and laboratory analysis. This paper presents new zooarchaeological evidence from Middle and Late Bronze Age Kaymakçı in the Marmara Lake Basin of western Türkiye to present evidence of an ancient wetland. Situated in the middle Gediz Valley within a pulse-lake landscape shaped by seasonal flooding, spring discharge, and ecological verticality extending from the basin floor to approximately 2150 m at the peak of Bozdağ, Kaymakçı is currently the largest-known second-millennium BCE settlement not only in this niche zone, but also in wider western Anatolia. The Kaymakçı Archeological Project (KAP) results show that recovery methods, especially heavy fraction, may significantly affect the resulting data and, therefore, the interpretations. The identified fish remains from KAP, dominated by carp and catfish, confirm a large, shallow, vegetated wetland with fluctuating littoral and flood-zone habitats. Bird remains also evidence a taxonomically diverse bird community typical of large wetland zones with nearby mountain ranges, including waterfowl, marsh-edge, and terrestrial taxa. Compared with contemporaneous Anatolian assemblages from central and southeastern regions of Anatolia, the KAP data extend our understanding of seasonally dynamic wetlands in western Anatolia and further confirm the value of integrated faunal analysis. Full article

Geochemical anomaly detection plays a critical role in mineral exploration, yet conventional methods are often limited by compositional effects, sensitivity to outliers, and insufficient consideration of spatial relationships. To address these issues, this study proposes an integrated analytical framework that combines compositional data analysis and spatial statistics for robust geochemical anomaly identification. The framework incorporates isometric log-ratio (ILR) transformation to eliminate the closure effect, robust principal component analysis (RPCA) to extract stable geochemical patterns, local indicators of spatial association (LISAs) to characterize spatial clustering, and compositional balance analysis (CoBA) to enhance anomaly signals. The method is applied to the Barkol Lake area in the Eastern Tianshan, a key metallogenic belt within the Central Asian Orogenic Belt. The results reveal significant geochemical anomalies characterized by Cu-associated element assemblages (e.g., Cu–Ni–Cr), which are spatially correlated with major fault zones and volcanic–intrusive complexes. The identified anomalies show strong consistency with known mineral occurrences and delineate several prospective targets for copper polymetallic mineralization. Compared with conventional approaches, the proposed framework demonstrates improved robustness to outliers, enhanced sensitivity to weak anomalies, and better integration of compositional and spatial constraints. Full article

Groundwater quality in arid and semi-arid regions is increasingly affected by salinization, evaporation, abstraction, and agricultural return flow. This study evaluates the hydrochemical evolution, isotopic characteristics, ²²²Rn activity, and water-use suitability of groundwater and associated waters in Karbala Governorate, central Iraq. Seventeen groundwater, lake water, and municipal supply water samples were analyzed for physicochemical parameters, major ions, δ¹⁸O, δ²H, and ²²²Rn. Hydrochemical, isotopic, and water-quality assessment methods were applied to evaluate groundwater evolution, salinization, and suitability for drinking and irrigation. The waters are near-neutral, with pH values of 6.18–7.35, but are strongly mineralized. Electrical conductivity ranges from 1440 to 16,305 µS/cm, and total dissolved solids (TDS) range from 592 to 10,191 mg/L. Most samples belong to a Ca–Mg–SO₄–Cl facies, indicating sulfate- and chloride-rich hard water evolution. The highest mineralization occurs near Karbala proper and lake-influenced sites. Ion ratios and chloro-alkaline indices indicate that evaporite dissolution, gypsum/anhydrite dissolution, carbonate interaction, evaporation, and local ion exchange jointly control groundwater chemistry. Stable isotopes indicate meteoric origin with variable evaporative enrichment; however, highly saline but isotopically depleted water, particularly W8, shows that evaporation alone cannot explain salinization. ²²²Rn activities range from below detection to 11.28 Bq/L and mainly reflect local aquifer contact and degassing. High TDS, sulfate, chloride, and very high hardness limit suitability for drinking-water use. For irrigation, the sodium hazard is low, but salinity, hardness, magnesium hazard, and permeability constraints make most samples unsuitable or restricted. Management should prioritize salinity and hardness control, treatment or blending before domestic use, restricted irrigation of the least saline wells under drainage and soil-salinity monitoring, protection of less mineralized recharge zones, and long-term monitoring of lake-adjacent and agriculturally influenced wells. Full article

Determining the relative impacts of climate variability and human activities on vegetation dynamics remains a central theme in paleoecological research. In climate transition zones like the southeastern Marmara region, isopollen maps are important because they allow for the evaluation of spatially diverse pollen records within an integrated regional framework. The aim of this study is to present a spatially holistic reconstruction of Late Holocene vegetation change in the southern Marmara region using isopollen maps based on fossil pollen records obtained from Manyas, Iznik and Sapanca lakes. Isopollen maps were created for five time periods, approximately 2600, 2000, 1250, 800 and 400 yr BP, representing major climatic and historical phases of the Late Holocene, and the spatial distribution patterns of the major tree and herbaceous taxa were reconstructed. The results demonstrate the presence of a continuous west–east variability in the region’s vegetation structure, reflecting the transition between Mediterranean and Black Sea climate regimes. However, the temporal variation patterns show that vegetation responses cannot always be directly explained by climatic phases. In particular, Artemisia highlights the persistence and local expansion of open-area vegetation, reaching approximately 24% of the study area to the present day. Given the region’s long history of settlement, these findings indicate that vegetation dynamics during the Late Holocene were shaped by the combined effects of climatic changes, local environmental conditions and human activities. Therefore, the study emphasizes the importance of spatially integrated approaches in paleoecological reconstructions. Full article

Developing ecological networks is essential for preserving regional ecosystem stability and for reducing risks associated with degraded landscape security and ecological health. However, regional ecological network studies in lake environments that combine long-term temporal comparison with location-specific optimization remain relatively limited. Taking the Chagan Lake region as the study area, this research examined landscape pattern changes in 2000, 2010, and 2020 by integrating Morphological Spatial Pattern Analysis (MSPA) with connectivity metrics to determine major ecological source areas. General and key ecological corridors were then identified and evaluated through the joint use of the Minimum Cumulative Resistance (MCR) model and the gravity model. Based on these results, the evolution of the regional ecological network during the past two decades was analyzed, and an optimization strategy was proposed. The results show that important ecological source areas became increasingly fragmented over time. Although corridor numbers continued to rise, connectivity between the eastern and western sectors and across parts of the central zone remained weak. In response, three supplementary ecological source areas, together with restoration nodes and stepping-stone patches, are proposed to reinforce structural linkage and improve the overall network configuration. The study offers a practical basis for ecological network refinement in the Chagan Lake region and provides methodological support for enhancing landscape connectivity and ecosystem resilience. Full article

In recent years, the distribution of potassium salt resources in the Central Asia–Tarim Basin salt lake chain has shown an asymmetric pattern, and exploration efforts in the northwestern Tarim Basin have not seen significant progress. This study focuses on the central Bachu Uplift within the Central Asia–Tarim Basin salt lake chain. The characteristics of subsurface brines and indicators of potash formation are investigated. By examining various potassium exploration indices, such as the potassium–chlorine coefficient and magnesium–chlorine coefficient, along with comprehensive analysis of hydrogen–oxygen, sulfur, and strontium isotopes, this research serves to evaluate the potential for potash formation in the central Bachu Uplift. Analysis shows a brine salinity of 12.69–88.46 g/L and a potassium concentration of 0.07–0.65 g/L. The hydrochemical coefficients indicate a high nNa/nCl value, with low K × 10³/Cl values. All brine samples plot within the halite phase field of the 25 °C Na⁺,K⁺,Mg²⁺//C1⁻-H₂O Quaternary metastable phase diagram, clustering towards the Na-rich end. This indicates that the brine likely originated from halite dissolution. In the Na⁺,K⁺,Mg²⁺//C1⁻,SO₄²⁻-H₂O Quinary metastable phase diagram, the majority of samples project within the mirabilite phase field, trending toward the sylvite field. This suggests that the shallow subsurface brine may still be in the early to middle stages of sylvite deposition. Hydrogen and oxygen isotopes indicate that the brine samples were influenced by water–rock interaction and strong evaporative concentration; strontium isotopes reveal their marine–continental transitional characteristics; and sulfur isotopes suggest that the sulfur in the samples was derived from the weathering of Meso-Cenozoic gypsum in the western Tarim Basin. This integrated evidence implies that the brines in the central Bachu Uplift contain a deep-seated potassium anomaly, with fault zones likely conveying information about deep potash resources. This provides preliminary evidence for potassium exploration in the area and holds significant indicative value for identifying key prospective targets. Full article

The Central Rift Valley (CRV) of Ethiopia is an ecologically and socioeconomically important region increasingly threatened by environmental degradation driven by unsustainable land and water use, population growth, and climate variability. This review synthesizes existing literature to provide an integrated assessment of hydrological, ecological, and social dimensions in the CRV. The study draws on published data and reports to evaluate water resource depletion, pollution, biodiversity loss, wetland degradation, land use change, and their impacts on livelihoods and habitability. Results indicate that lakes and groundwater resources are under severe stress from agricultural intensification, industrial expansion, and urbanization, leading to declining water availability and deteriorating quality. Land cover change, wetland loss, and deforestation have reduced ecosystem resilience and accelerated biodiversity decline. Governance frameworks remain fragmented and often fail to address the complex interactions between hydrology, ecology, and human activities. The review concludes that adopting a Critical Zone Science (CZS) perspective offers a comprehensive framework for linking land, water, ecological, and social processes, and that integrated land and water management, ecosystem restoration, and climate-resilient strategies are essential to improve sustainability and community well-being. Full article

Although sedimentary zones in Lake Taihu differ in external inputs, hydrodynamic conditions, and sedimentary settings, the spatial differentiation of eukaryotic microbial communities and their assembly mechanisms remain insufficiently understood. This study analyzed sediment cores from four typical sedimentary zones of Lake Taihu: Dapu (DP), Gonghu (GH), the central lake area (HX), and Xuhu (XH). By integrating physicochemical measurements, 18S rRNA gene high-throughput sequencing, redundancy analysis, functional annotation, iCAMP, and co-occurrence network analysis, we characterized the composition, environmental associations, and assembly mechanisms of sedimentary eukaryotic microbial communities. The results showed that eukaryotic microbial communities in Lake Taihu sediments exhibited marked spatial heterogeneity, with dominant taxonomic groups including Chlorophyta, Intramacronucleata, and Diatomea. Alpha diversity was higher in the GH zone and lower in the HX zone, whereas beta diversity showed significant separation among lake zones. NH₄⁺-N, NO₃⁻-N, TN, TP, TOC, D50, MWC, and pH were associated with variation in community composition, but the main associated factors differed among zones. FunGuild annotation showed that annotated fungal functional groups exhibited distinct trophic distribution patterns across sedimentary zones. iCAMP analysis indicated that community assembly was generally dominated by stochastic processes, with dispersal limitation prevailing in the GH zone and ecological drift dominating in the DP, HX, and XH zones. Co-occurrence network analysis further revealed marked differentiation in potential biological associations among sedimentary zones. Overall, this study showed that nutrient conditions and sediment physical properties in different sedimentary environments of Lake Taihu jointly shaped the spatial patterns of eukaryotic microbial communities and their ecological associations, providing baseline information for understanding sedimentary ecological processes in eutrophic shallow lakes. Full article

Dissolved organic matter (DOM) plays a central role in estuarine carbon cycling and exhibits dynamically coupled interactions with chlorophyll-a (Chl-a). Under increasing nutrient loads, elevated Chl-a concentrations and shifts in DOM composition serve as key indicators of eutrophication in estuarine aquatic ecosystems. Previous studies have mainly focused on the composition and fluorescence properties of DOM in rivers and lakes. Here, 84 water samples were collected from the Ganjiang River Estuary of Lake Poyang during wet, normal, and dry seasons across the mainstream, middle, and south branches. The average Chl-a concentration showed wet season (6.61 μg·L⁻¹) > normal season (4.54 μg·L⁻¹) > dry season (2.01 μg·L⁻¹). By employing EEM-PARAFAC, five fluorescent components were identified, including C1, C2, C3, C4, and C5. Notably, microbial humic-like substances remained consistently high during the wet season. Two-dimensional correlation spectroscopy was further employed to evaluate sequential changes in DOM components, while a moving window was used to identify temporal variation characteristics. Based on Noda’s rules, the DOM response sequence was identified as C3→C2→C1→C4→C5. Kernel PCA showed that the variable cluster represented by PC1, which consisted of organic pollutants and nutrients, co-varied negatively with Chl-a, whereas the PC2 cluster, representing biogenic organic matter, co-varied positively with Chl-a. Moreover, partial least squares path modeling showed that humic-like and tryptophan-like substances were positively correlated with Chl-a, with the path coefficients of 0.47 and 0.19, respectively. These findings revealed the interaction patterns between DOM components and Chl-a at the river-lake confluence zone, thereby enhancing our understanding of the factors influencing the spatio-temporal variations in Chl-a concentration, and further providing a guide for the control of algal blooms. Full article