Search Results (65)

This comprehensive study investigates the spatial distribution of metals in surface water, their accumulation in fish tissues, and their impact on the gut microbiome dynamics of fish in the Qi River, Huanggang City, Hubei Province. Three distinct sampling regions were established: the mining area (A), the transition area (B), and the distant area (C). Our results revealed that metal concentrations were highest in the mining area and decreased with increasing distance from it. The bioaccumulation of metals in fish tissues followed the order of gut > brain > muscle, with some concentrations exceeding food safety standards. Analysis of the gut microbiota showed that Firmicutes and Proteobacteria dominated in the mining area, while Fusobacteriota were more prevalent in the distant area. Heavy metal pollution significantly altered the composition and network structure of the gut microbiota, reducing microbial associations and increasing negative correlations. These findings highlight the profound impact of heavy metal pollution on both fish health and the stability of their gut microbiota, underscoring the urgent need for effective pollution control measures to mitigate ecological risks and protect aquatic biodiversity. Future research should focus on long-term monitoring and exploring potential remediation strategies to restore the health of affected ecosystems. Full article

The sharp decline in streamflow prediction accuracy with increasing lead times remains a persistent challenge for effective water resources management and flood mitigation. In this study, we developed a coupled deep learning model for daily streamflow prediction in the Hanjiang River Basin, China. The proposed model integrates self-attention (SA), a one-dimensional convolutional neural network (1D-CNN), and bidirectional long short-term memory (BiLSTM). The model’s effectiveness was assessed during flood events, and its predictive uncertainty was quantified using kernel density estimation (KDE). The results demonstrate that the proposed model consistently outperforms baseline models across all lead times. It achieved Nash-Sutcliffe Efficiency (NSE) scores of 0.92, 0.86, and 0.79 for 1-, 3-, and 5-days, respectively, showing particular strength at these extended lead time predictions. During major flood events, the model demonstrated an enhanced capacity to capture peak magnitudes and timings. It achieved the highest NSE values of 0.924, 0.862, and 0.797 for the 1-, 3-, and 5-day forecasting horizons, respectively, thereby showcasing the strengths of integrating CNN and SA mechanisms for recognizing local hydrological patterns. Furthermore, KDE-based uncertainty analysis identified a high prediction interval coverage in different forecast periods and a relatively narrow prediction interval width, indicating the strong robustness of the proposed model. Overall, the proposed SA-CNN-BiLSTM model demonstrates significantly improved accuracy, especially for extended lead times and flood events, and provides robust uncertainty quantification, thereby offering a more reliable tool for reservoir operation and flood risk management. Full article

Background: Ulva is a globally distributed genus with ecological and economic significance, yet the codon usage bias of the Ulva chloroplast genome remains poorly understood. Methods: We assessed the Ulva chloroplast genome codon usage patterns and their drivers by analyzing 30 genomes across 16 Ulva species. Results: The nucleotide composition analysis demonstrated that Ulva chloroplast genomes are rich in A/T, and prefer to use codons that ended with A/T. The relative synonymous codon usage analysis suggested that related species have similar codon usage patterns. A total of 25 high-frequency codons and 7–14 optimal codons were identified in these chloroplast genomes. The ENC values ranged from 31.40 to 32.76, all of which are less than 35, illustrating a strong codon bias of the Ulva genus. Our comparative analyses suggested that natural selection played the main role in the formation of the codon usage bias. Furthermore, the correlation analysis indicated that an influence of the base composition and gene expression levels on the codon usage bias. Conclusions: This study provides the first comprehensive analysis of the codon usage patterns in Ulva chloroplast genomes, improving our understanding of the genetics and evolution of these economically and ecologically important macroalgae. Full article

The Miocene Hanjiang Formation (HJF) is a remarkable exploration target in the Pearl River Mouth Basin (PRMB). However, challenges such as bias in current sequence stratigraphic schemes, limitations in high-resolution stratigraphic schemes, and incomplete understanding of genetic mechanisms may present obstacles for refining hydrocarbon exploration strategies. This study integrates gamma ray (GR) logging data, lithological variations, sequence stratigraphy, and cyclostratigraphy to delineate connections between sequence stratigraphy and astronomical forcing. The analysis utilizes gamma-ray logging data from boreholes LFA (1250–1960 m) and LFB (1070–1955 m) in the HJF. We constructed an absolute astronomical time scale anchored at the HJF’s top boundary (10.221 ± 0.4 Ma), identifying 6 third-order sequences through detailed analysis. Notably, 18 long-eccentricity cycles (405 kyr) and distinctive 1.2-Myr obliquity modulation signals were detected in the stratigraphic record. Our study demonstrates distinct connection between third-order sequence boundaries and the 1.2-Myr obliquity cycles, congruent with both global eustatic sea-level fluctuations and regional sea-level changes in the PRMB. The integration of cyclostratigraphic methods with sequence stratigraphic analysis proves particularly valuable for objective stratigraphic subdivision and understanding third-order sequence evolution in the divergent continental margin settings of the South China Sea. This approach enhances temporal resolution on a regional scale while revealing astronomical forcing mechanisms governing sedimentary cyclicity. Full article

Background/Objectives: Abiotic stresses severely constrain the yield of Brassica juncea, and aldehyde dehydrogenases (ALDHs) play a pivotal role in plant stress resistance. This study aims to systematically identify the ALDH gene family members in B. juncea and elucidate their expression patterns under salt and drought stress. Methods: Using the Arabidopsis thaliana AtALDH proteins as seed sequences, BLASTp alignment was performed against the B. juncea whole-protein sequence database, combined with the conserved domain PF00171 of the ALDH proteins. A total of 39 BjALDH gene family members were identified, and their physicochemical properties, structures, phylogenetic relationships, interspecies collinearity, and intraspecies collinearity were analyzed. The qRT-PCR method was employed to quantify the relative expression levels of the BjALDH genes potentially associated with stress resistance under various treatments, and their effects on drought and salt stress tolerance were evaluated. Results: The results demonstrated that BjALDH were universally significantly upregulated under salt stress, while exhibiting predominantly upregulated trends under drought stress. These findings suggest that BjALDH may enhance plant resistance to both salt and drought stress by modulating the aldehyde metabolic pathways. Conclusions: This study provides a theoretical basis for elucidating the functional roles and molecular genetic mechanisms of the BjALDH gene family in B. juncea under salt and drought stress. Full article

Chilli veinal mottle virus (ChiVMV) severely compromises the quality and yield of solanaceous crops. The helper component protease (HCPro) of ChiVMV functions as a multifunctional RNA silencing suppressor that subverts host antiviral defenses through diverse strategies, However, the underlying mechanisms remain mechanistically unresolved. In this study, HCPro-overexpressing (HCPro-OX) and wild-type (WT) plants were inoculated with ChiVMV to monitor the physiological and molecular changes. Transcriptome analysis identified 11,815 differentially expressed genes (DEGs) under viral infection, among which 1115 genes were specifically regulated by HCPro. KEGG enrichment analysis revealed that the DEGs were significantly associated with plant hormone signal transduction pathways, indicating their crucial role in host–virus interactions. Furthermore, functional clustering of HCPro-regulated DEGs specifically identified key components in ethylene biosynthesis pathways. GO analysis of DEGs between virus-inoculated WT and HCPro-OX plants annotated ethylene biosynthesis-related genes NtACO and NtACS. qPCR validation confirmed that the expression of ethylene biosynthesis-related genes was suppressed by HCPro. Exogenous treatments with the ethylene precursor ACC demonstrated that ethylene suppressed viral accumulation, enhanced POD activity, and reduced the ROS accumulation induced by viral infection. In conclusion, our results demonstrate that HCPro promotes viral infection by suppressing ethylene biosynthesis, which in turn attenuates peroxidase activity, leading to ROS accumulation. Full article

Xiangyang City is the core area of soil erosion in the Han River Basin, with serious problems of soil erosion and a weak soil conservation capacity. The spatiotemporal evolution characteristics and influencing factors of soil conservation in Xiangyang City, Han River Basin, from 2000 to 2020 were analyzed using the InVEST-SDR model and the PLUS contribution methodology. The results show the following: (1) The amount of soil conservation per unit area in Xiangyang in 2000, 2010, and 2020 was 1.84 × 10⁵ t/km², 1.59 × 10⁵ t/km², and 1.96 × 10⁵ t/km². This was concentrated in some areas, such as Baokang County, Nanzhang County, and Gucheng County. The soil conservation in Zaoyang, Xiangzhou, Yicheng, and Laohekou was relatively low, while the soil conservation capacity in the Xiangcheng and Fancheng areas was weakest. (2) The areas with the highest value of soil conservation were mainly concentrated in the forest areas in the southwest and northwest of Xiangyang, where the vegetation coverage is high and the altitude is low. The areas with low soil conservation were mainly concentrated in the eastern central part of Xiangyang, which is mainly farmland, with less vegetation and relatively flat terrain. (3) The amount of soil conservation is mainly influenced by two factors—vegetation coverage and terrain—indicating that vegetation management strategies should be tailored to local conditions. This article differs from previous watershed research areas by exploring the influencing factors of soil conservation in Xiangyang City and deeply analyzing the changes in importance and the spatiotemporal differentiation of ecosystem service functions. This conclusion can provide data support for environmental management and decision-making in the Xiangyang region, helping to achieve the sustainable development of the regional ecological environment and economic society. Full article

A SWAT (soil and water assessment tool) model was built to elucidate the spatiotemporal dynamic changes in blue/green water resources during 1980–2019 in the Hanjiang River Basin, China. Several scenarios were constructed to analyze the spatiotemporal differentiation between green and blue water resources in diverse climate and land utilization conditions. The results showed that (1) the mean blue water and green water resources were 392.24 and 410.48 mm/year; (2) the blue water resources showed a non-significant fluctuating decreasing trend, while the green water resources showed a non-significant increasing trend in volume; (3) the high-value areas of the blue water resources were concentrated in the western, northeastern, and southeastern parts of the Hanjiang River Basin, whereas the western region had more abundant green water resources; (4) compared with the effects of land use change, the climate factors contributed much more to variations in the blue/green water resources of the Hanjiang River Basin. Overall, the blue/green water resources in most areas of the Hanjiang River Basin had a downward trend during 1980–2019. The findings may offer theoretical support for the optimal allocation and management of water resources in the Hanjiang River Basin, China, under climate change. Full article

Optimizing the joint drawdown operation of mega reservoirs presents a significant opportunity to enhance the comprehensive benefits among hydropower output, water release, and carbon emission reduction. However, achieving the complementary drawdown operation of mega reservoirs while considering reservoir carbon emissions poses a notable challenge. In this context, this study introduces an innovative multi-objective optimization framework tailored for the joint drawdown operation of mega reservoirs. Firstly, a multi-objective optimization model, leveraging an intelligent evolutionary algorithm, is developed to minimize reservoir carbon emissions (Objective 1), maximize hydropower output (Objective 2), and maximize water release (Objective 3). Subsequently, a multi-criteria decision-making approach to search for the optimal scheme is employed. The proposed framework is applied to seven mega reservoirs within the Hanjiang River basin, China. The results show that the framework is effective in promoting comprehensive benefits, improving hydropower production by 8.3%, reservoir carbon emission reduction by 5.6%, and water release by 6.2% from the optimal solution under wet scenarios, compared to standard operation policies. This study not only provides a fresh perspective on the multi-objective drawdown operation of mega reservoirs but also offers valuable support to stakeholders and decision-makers in formulating viable strategic recommendations that take potential carbon emissions and advantages into account. Full article

A new species of Asian horned toad, Boulenophrys, is described from Yongzhou City, Hunan Province, China. The species is a phylogenetically sister to B. yunkaiensis, based on 16S rRNA and COI genes. The new species differs from its congeners, possessing the following combination of characters: (1) moderate body size: SVL 37.6–40.2 mm (38.9 ± 1.3, n = 7) in adult males and SVL 41.8–45.9 mm (43.6 ± 2.1, n = 3) in adult females; (2) tympanum boundary clear: TD/ED 0.48–0.57 in males and 0.47–0.57 in females; (3) the presence of a small horn-like tubercle at the edge of the upper eyelid; (4) vomerine ridge present and vomerine teeth absent; (5) margin of tongue rounded, not notched posteriorly; (6) rough dorsal skin: a discontinuous “V”-shaped ridge with two discontinuous dorsolateral ridges on two sides on the back, dense tubercles on the skin of the ventral surface of the dorsal shank and thigh, and spiny tubercles surrounding the cloaca; (7) slender hindlimbs with heels overlapping when the flexed hindlimbs are held at right angles to the body axis; tibio-tarsal articulation reaching forward between anterior margin of tympanum and posterior corner of eye when leg stretched forward; (8) relative finger length IV < II < I < III, with a subarticular tubercle present at the base of each finger; (9) distinct supernumerary tubercles below the base of I and II toes; (10) toes without lateral fringes and with rudimentary webbing (webbing formula: I1 − 1-II1 − 2-III2 − 3IV3- − 2V). Full article

As a vital part of the geo-environment and water cycle, ecosystem health and human development are dependent on water resources. Water supply and demand are influenced significantly by land use and cover change (LUCC) which shapes the surface ecosystems by altering their structure and function. Under future climate change scenarios, LUCC may greatly impact regional water balance, yet the impact is still not well understood. Therefore, examining the spatial relationship between LUCC and water yield services is crucial for optimizing land resources and informing sustainable development policies. In this study, we focused on the Hanjiang River Basin and used the patch-generating land use simulation (PLUS) model, coupled with the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model, to assess water yield services under three Shared Socioeconomic Pathway and Representative Concentration Pathway (SSP-RCP) scenarios. For the first time, we considered the impact of future changes in socio-economic and water use indicators on water demand using correction factors and ARIMA projections. The relationship between water supply and demand was explored using this approach, and LUCC’s effects on this balance are also discussed. Results indicate that: (1) The patterns of LUCC are similar for the three scenarios from 2030 to 2050, with varying levels of decrease for cropland and significant growth of built-up areas, with increases of 6.77% to 19.65% (SSP119), 7.66% to 22.65% (SSP245), and 15.88% to 46.69% (SSP585), respectively, in the three scenarios relative to 2020; (2) The future supply and demand trends for the three scenarios of produced water services are similar, and the overall supply and demand risks are all on a downward trend. Water demand continues to decline, and by 2050, the water demand of the 3 scenarios will decrease by $96.275\times {10}^8\mathrm{t}$, $81.210\times {10}^8\mathrm{t}$, and $84.13\times {10}^8\mathrm{t}$ relative to 2020, respectively; while supply decreases from 2030 to 2040 and rises from 2040 to 2050; (3) Both water supply and demand distributions exhibit spatial correlation, and the distribution of hotspots is similar. The water supply and demand are well-matched, with an overall supply-demand ratio greater than 1.5; (4) LUCC can either increase or decrease water yield. Built-up land provides more water supply compared to other land types, while forest land has the lowest average water supply. Limiting land use type conversions can enhance the water supply. Full article

Monthly runoff prediction is crucial for water resource allocation and flood prevention. Many existing methods use identical deep learning networks to understand monthly runoff patterns, neglecting the importance of predictor selection. To enhance predictive accuracy and reliability, this study proposes an RFECV–SSA–LSTM forecasting approach. It iteratively eliminates predictors derived from SSA decomposition and PACF using recursive feature elimination and cross-validation (RFECV) to identify the most relevant subset for predicting the target flow. LSTM modeling is then used to forecast flows 1–7 months into the future. Furthermore, the RFECV–SSA framework complements any machine-learning-based runoff prediction method. To demonstrate the method’s reliability and effectiveness, its outputs are compared across three scenarios: direct LSTM, MIR–LSTM, and RFECV–LSTM, using monthly runoff historical data from Yangxian and Hanzhong hydrological stations in the Hanjiang River Basin, China. The results show that the RFECV–LSTM method is more robust and efficient than the direct LSTM and MIR–LSTM counterparts, with the smallest number of outliers for NSE, NRMSE, and PPTS under all forecasting scenarios. The MIR–LSTM approach exhibits the worst performance, indicating that single-metric-based feature selection may eliminate valuable information. The SSA time–frequency decomposition is superior, with NSE values remaining stably around 0.95 under all scenarios. The NSE value of the RFECV–SSA–LSTM method is greater than 0.95 under almost all forecasting scenarios, outperforming other benchmark models. Therefore, the RFECV–SSA–LSTM method is effective for forecasting highly nonlinear runoff series, exhibiting high accuracy and generalization ability. Full article

The hydrological cycle is altered by climate change and human activities, amplifying extreme precipitation and heightening the flood risk regionally and globally. It is imperative to explore the future possible alterations in flood risk at the regional scale. Focusing on the Hanjiang river basin (HRB), this study develops a framework for establishing a scientific assessment of spatio-temporal dynamics of future flood risks under multiple future scenarios. In this framework, a GCMs statistical downscaling method based on machine learning is used to project future precipitation, the PLUS model is used to project future land use, the digitwining watershed model (DWM) is used to project future runoff, and the entropy weight method is used to calculate risk. Six extreme precipitation indices are calculated to project the spatio-temporal patterns of future precipitation extremes in the HRB. The results of this study show that the intensity (Rx1day, Rx5day, PRCPTOT, SDII), frequency (R20m), and duration (CWD) of future precipitation extremes will be consistently increasing over the HRB during the 21st century. The high values of extreme precipitation indices in the HRB are primarily located in the southeast and southwest. The future annual average runoff in the upper HRB during the near-term (2023–2042) and mid-term (2043–2062) is projected to decrease in comparison to the baseline period (1995–2014), with the exception of that during the mid-term under the SSP5-8.5 scenario. The high flood risk center in the future will be distributed in the southwestern region of the upper HRB. The proportions of areas with high and medium–high flood risk in the upper HRB will increase significantly. Under the SSP5-8.5 scenario, the area percentage with high flood risk during the future mid-term will reach 24.02%. The findings of this study will facilitate local governments in formulating effective strategic plans for future flood control management. Full article

Water ecological problems involve flood, drought, water pollution, destruction of water habitat and the tense relationship between humans and water. Water ecological problems are the main problems in the development of countries all over the world. In terms of ecological protection, China has put forward the ecological red line policy. Water ecology is an important component of the ecosystem, and the delineation of the water ecological red line is an important basis for ecological protection. Based on ecosystem services, this paper tries to determine the red line of the water ecology space and tries to solve various water problems comprehensively. Based on the ecosystem services accounting method, the SWAT (soil and water assessment tool) model was used to simulate the spatial–temporal dynamic quantities of water purification and rainwater infiltration services in the upper reaches of the Hanjiang River. The basin was divided into 106 sub-basins and 1790 HRUs (hydrological response units). Water quality data taken from 8 sites were used to verify the simulation results, and the verification results have high reliability. The grid scale spatialization of water quality and rainwater infiltration is realized based on HRU. The seasonal characteristics of hydrological regulation and control services were analyzed, the red line of hydrological regulation and control in the upper reaches of the Hanjiang River was defined, and the dynamic characteristics of water ecological red line were analyzed. According to the research results, the water ecological protection strategy of the basin is proposed. The prevention and control of water pollution should be emphasized in spring and summer, the prevention and control of rain flood infiltration in autumn and winter, and the normal monitoring and management should be adopted in the regulation and storage. The results of this study can provide scientific reference for water resources management and conservation policy making. Full article

Based on the principle of water supply and demand flow and the natural flow of water, this paper analyzes the flow direction and discharge of water resources in the study area. In order to provide scientific and systematic implementation suggestions for regional water resource protection management and ecological compensation, a SWAT (Soil and Water Assessment Tool) model was constructed to quantify the water resource supply of the upper Hanjiang River basin at three spatial scales: pixel, sub-basin, and administrative unit. The water demand at the three spatial scales was calculated using the LUCC (Land Use and Land Coverage) and water consumption index. The supply and benefit zones under different spatial and temporal scales were obtained. Simultaneously, this study uncovered the spatiotemporal dynamics inherent in water resource supply and demand, alongside elucidating the spatial extent and flow attributes of water supply. The ecological compensation scheme of water resource supply–demand was preliminarily determined. The findings indicate an initial increase followed by a decrease in both the water supply and demand in the upper reaches of the Han River, accompanied by spatial disparities in the water supply distribution. The direction of the water supply generally flows from branch to main stream. The final ecological compensation scheme should be combined with natural conditions and economic development to determine a reasonable financial compensation system. Full article