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Abstract Coordination engineering of high-valent Fe(IV)-oxo (FeIV=O) is expected to break the activity-selectivity trade-off of traditional reactive oxygen species, while attempts to regulate the oxidation behaviors of heterogeneous FeIV=O remain unexplored. Here, by coordination engineering of Fe-Nx single-atom catalysts (Fe-Nx SACs), we propose a feasible approach to regulate the oxidation behaviors of heterogeneous FeIV=O. The developed Fe-N2 SACs/peroxymonosulfate (PMS) system delivers boosted performance for FeIV=O generation, and thereby can selectively remove a range of pollutants within tens of seconds. In-situ spectra and theoretical simulations suggest that low-coordination Fe-Nx SACs favor the generation of FeIV=O via PMS activation as providing more electrons to facilitate the desorption of the key *SO4H intermediate. Due to their disparate attacking sites to sulfamethoxazole (SMX) molecules, Fe-N2 SACs mediated FeIV=O (FeIVN2=O) oxidize SMX to small molecules with less toxicity, while FeIVN4=O produces series of more toxic azo compounds through N-N coupling with more complex oxidation pathways.

Arsenic exposure has long been a significant global health concern due to its association with various human diseases. The adverse health effects of arsenic can be influenced by multiple factors, resulting in considerable individual variability. Individuals with inflammatory bowel disease (IBD) are particularly vulnerable to the effects of toxin exposure, yet the specific impact of arsenic in the context of IBD remains unclear. In this study, we employed a non-targeted metabolomics approach to investigate how arsenic exposure affects metabolic homeostasis in an IBD model using Helicobacter trogontum-infected interleukin-10 deficient mice. Our results demonstrated that arsenic exposure disrupted the balance of various metabolites, including tryptophan, polyunsaturated fatty acids, purine and pyrimidine metabolites, and branched-chain amino acids, in mice with colitis but not in those without colitis. Notably, several crucial metabolites involved in anti-inflammatory responses, oxidative stress, and energy metabolism were significantly altered in mice with colitis. These results indicate that arsenic exposure in an IBD context can lead to extensive metabolic disturbances, potentially exacerbating disease severity and impacting overall health. This study underscores the necessity of evaluating arsenic toxicity in relation to IBD to better understand and mitigate associated health risks.

Land use/land cover represents the interactive and comprehensive influences between human activities and natural conditions, leading to potential conflicts among natural and human-related issues as well as among stakeholders. This study introduced economic standards for farmers. A hybrid approach (CA-ABM) of cellular automaton (CA) and an agent-based model (ABM) was developed to effectively deal with social and land-use synergic issues to examine human–environment interactions and projections of land-use conversions for a humid basin in south China. Natural attributes and socioeconomic data were used to analyze land use/land cover and its drivers of change. The major modules of the CA-ABM are initialization, migration, assets, land suitability, and land-use change decisions. Empirical estimates of the factors influencing the urban land-use conversion probability were captured using parameters based on a spatial logistic regression (SLR) model. Simultaneously, multicriteria evaluation (MCE) and Markov models were introduced to obtain empirical estimates of the factors affecting the probability of ecological land conversion. An agent-based CA-SLR-MCE-Markov (ABCSMM) land-use conversion model was proposed to explore the impacts of policies on land-use conversion. This model can reproduce observed land-use patterns and provide links for forest transition and urban expansion to land-use decisions and ecosystem services. The results demonstrated land-use simulations under multi-policy scenarios, revealing the usefulness of the model for normative research on land-use management.

Predicting and allocating surface water resources are becoming increasingly important tasks for addressing the risk of water shortages and challenges of climate change, especially in reservoir basins. However, surface water resource management includes many systematic uncertainties and complexities that are difficult to address. Thus, advanced models must be developed to support predictive simulations and optimal allocations of surface water resources, which are urgently required to ensure regional water supply security and sustainable socioeconomic development. In this study, a soil and water assessment tool-based interval linear multi-objective programming (SWAT-ILMP) model was developed and integrated with climate change scenarios, SWAT, interval parameter programming, and multi-objective programming. The developed model was applied to the Xinfengjiang Reservoir basin in South China and was able to identify optimal allocation schemes for water resources under different climate change scenarios. In the forecast year 2025, the optimal water quantity for power generation would be the highest and account for ∼60% of all water resources, the optimal water quantity for water supply would account for ∼35%, while the optimal surplus water released from the reservoir would be the lowest at ≤5%. In addition, climate change and reservoir initial storage would greatly affect the surplus water quantity but not the power generation or water supply quantity. In general, the SWAT-ILMP model is applicable and effective for water resource prediction and management systems. The results from different scenarios can provide multiple alternatives to support rational water resource allocation in the study area.

Apportioning pollution sources under compound pollution conditions is challenging in river pollution source analysis. The positive matrix factorization (PMF) model is widely used to analyze river pollution sources. However, the identification of pollutants in this model relies primarily on the subjective experience of the researchers, leading to ineffective identification of different contaminants from similar sources. In this study, we propose a comprehensive deviation index (CDI) to quantitatively identify pollution source types based on the PMF and observed source profiles. Taking the subtropical Xizhijiang River Basin as a case study, we quantitatively identified the pollution sources and their contributions to dissolved organic carbon (DOC), total nitrogen (TN), and total phosphorus (TP) using observed water quality and pollution sources data. The results showed that the eight major pollutants in the study region exhibited significant positive correlations, indicating the similarity of pollutant sources in the watershed. The PMF model identified three primary pollution sources with coefficients of determination for observed versus predicted concentrations ranging from 0.60 to 0.98. The CDI unveiled that the watershed's three pollution sources were farmland, rural, and wastewater treatment plants (WTPs). Farmland emerges as the predominant contributor to DOC (68.04 %), TC (63.29 %), and TDP (44.51 %). Rural notably contributes to NH3-N, PO43−, TDP, and TN, with percentages of 86.37 %, 57.65 %, 41.40 %, and 30.45 %, respectively. WTPs significantly contribute to NO2−, NO3−, and TN, accounting for 71.81 %, 57.39 %, and 37.26 %, respectively. Incorporating source fingerprints into the PMF model, the CDI can accurately identify pollution sources, improve the interpretability of source identification, and mitigate uncertainty in the multiple-source unknown receptor model. These findings have immediate and practical implications for river ecosystem management and pollution control, providing a more effective method for identifying and addressing pollution sources.

Abstract Chibiraga is a mall East Asian genus in the family Limacodidae (slug-moths). The latter includes many agricultural pests. Mitochondrial genome analysis is an important tool for studying insect molecular identification and phylogenetics. However, there are very few mitogenome sequences available for Limacodidae species, and none for the genus Chibiraga at all. To explore the mitogenome features of Chibiraga and verify its phylogenetic position, the complete mitogenome of Chibiraga houshuaii was sequenced and annotated. The complete 15,487 bp genome encoded 37 mitochondrial genes, including 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, and a control region (CR). Most of the PCGs had typical ATN start codons and terminated with TAA or a single T residue. UUA (Leu2), AUU (Ile), UUU (Phe), AUA (Met) and AAU (Asn) were the five most frequently used codons. All tRNAs were folded into cloverleaf secondary structure, except for trnS1, which lacked the DHU arm. Phylogenetic analyses within the superfamily Zygaenoidea were performed based on multiple datasets from mitochondrial genes. The results showed that the families Phaudidae, Limacodidae and Zygaenidae were respectively recovered as monophyly; C. houshuaii was clustered in a clade with nettle type larvae in Limacodidae.

Abstract In this research, a modeling approach of rainfall generator coupled with high resolution rainfall products were proposed to generate designed rainfall events under multiple spatial and temporal distributions, which was then employed to analyze the impacts of spatial and temporal rainfall heterogeneities on peak runoff for watersheds. Three scenarios were developed under multiple degrees of impermeable underlying surface areas within an urban watershed in south China. Detailed runoff processes were analyzed through the adoption of a distributed hydrological model (GSSHA). A covariance analysis method combined with rainfall spatio‐temporal heterogeneity characteristic were used to quantify heterogeneity effects on peak runoff. Results indicated that coupling short period (2008–2016) remotely rainfall data and RainyDay results could successfully reproduce designed rainfall events, spatio‐temporal heterogeneity of rainfall contributed significantly to the peak runoff, which was greater than those by rainfall duration and capacity, and the increase in impermeable underlying surface enhanced the complexities of the effects. Over each rainfall duration with increasing rainfall return period, the indicator of rainfall peak coefficient (RWD) would decrease and then increase. Regarding the total rainfall center (tg), 25 mm/h threshold rainfall spatial coverage (A25) decreased with increasing imperviousness, 1‐h maximum rainfall (Rmax) surged with increasing imperviousness at rainfall duration of 2 and 24 h. Innovations of this research lied in: combination of a rainfall generator model based on a stochastic storm transposition technique and remote‐sensing rainfall data to generate designed rainfall events, a rainfall spatial and temporal heterogeneities index system was developed to reveal how the changing characteristics of rainfall distribution and the impacts on peak runoff, and in‐depth analysis of the impacts on runoff peak under multiple urban development scenarios for increasing capability in flood control/prevention.

Environmental DNA technology develops rapidly in the field of biodiversity detection. Selecting appropriate primers may be one of the key questions. However, there is currently a lack of systematic studies on differences in primer detection efficiencies. This research investigates the efficiency of six universal primers (12S, 16S, 18S, MiFish, Cytb, and COI) in detecting fish species across diverse aquatic ecosystems using an environmental DNA approach. The research spans five study areas, representing marine, river, wetland, lake, and reservoir ecosystems. Illumina MiSeq sequencing and bioinformatics tools were employed for primer performance evaluation. Results indicate that MiFish consistently outperforms other primers, detecting the highest number of fish species across all ecosystems and exhibiting superior taxonomic coverage. Furthermore, marine ecosystems consistently show higher detection numbers across all primers. The absence of commonly identified species detected by all primers emphasizes the necessity of using multiple primers for a comprehensive assessment. This study provides valuable insights into the strengths and limitations of universal primers, highlighting the importance of primer selection for accurate eDNA-based fish monitoring. The findings contribute to the scientific basis for the comprehensive management of aquatic ecosystems, assisting researchers and ecosystem managers in screening suitable fish universal primers for eDNA methods. The study also calls for further research into factors influencing primer performance and encourages the refinement of primers to enhance biodiversity monitoring precision in various ecosystems.

To address global phosphorus reduction challenges, we establish a quantitative framework for anthropogenic phosphorus emissions using a lifecycle model and decomposition analysis. Focusing on China's Pearl River Delta urban agglomeration, we highlight persistent difficulties in controlling phosphorus emissions from agricultural fertilizers and the emerging issue from industrial products. Emission intensity is a crucial factor for phosphorus reduction, yet gradually offset by affluence and population growth. Prioritizing agricultural control with supplementary industrial reduction, we delve into the decoupling challenge between phosphorus emissions, population expansion, and economic development. Proposing green economic development, our approach contributes to achieving sustainable phosphorus management goals.

Extreme heat-precipitation events, such as heatwaves and extreme precipitation, can have substantial impacts on the population, particularly in urbanized watersheds. However, few studies have investigated individual and compound extreme heat-precipitation events, causing much valuable information loss for watershed climate risk management. This study focuses on the Pearl River Basin (PRB), a highly urbanized area in southern China, and aims to predict changes in population exposure to extreme heat-precipitation events. To achieve this, a ranked ensemble global climate model (GCM) was used to generate projections for individual extreme precipitation, heatwaves, and sequential and coincident heat waves and precipitation extremes (SHWPs and CHWPs) under three future scenarios (SSP-RCPs). The main findings of the study are as follows: Precipitation extremes represent increasing extreme days and intensity under all three scenarios across the PRB. Towards the end of the 21st century, the SSP5-8.5 scenario predicts that heat waves will last ten times longer than historical records. Comparing two types of compound extreme events, we conclude that the 21st century will see a near-term high risk for SHWPs and a long-term high risk for CHWPs in the PRB. Furthermore, in both individual and compound heat-precipitation events, five hotspot cities in the PRB (i.e., Guangzhou, Dongguan, Foshan, Shenzhen, and Huizhou) will face higher population exposure to extreme heat-precipitation events. These cities share common characteristics: key to economic development, coastal, and densely populated. This study can provide insight into extreme climate risk management in other tropical and subtropical basins.

Microplastics (MPs), including conventional hard-to-biodegrade petroleum-based and faster biodegradable plant-based ones, impact soil structure and microbiota in turn affecting the biodiversity and functions of terrestrial ecosystems. Herein, we investigated the effects of conventional and biodegradable MPs on aggregate distribution and microbial community composition in microhabitats at the aggregate scale. Two MP types (polyethylene (PE) and polylactic acid (PLA) with increasing size (50, 150, and 300 μm)) were mixed with a silty loam soil (0–20 cm) at a ratio of 0.5 % (w/w) in a rice–wheat rotation system in a greenhouse under 25 °C for one year. The effects on aggregation, bacterial communities and their co-occurrence networks were investigated as a function of MP aggregate size. Conventional and biodegradable MPs generally had similar effects on soil aggregation and bacterial communities. They increased the proportion of microaggregates from 17 % to 32 %, while reducing the macroaggregates from 84 % to 68 %. The aggregate stability decreased from 1.4 mm to 1.0–1.1 mm independently of MP size due to the decline in the binding agents gluing soil particles (e.g., microbial byproducts and proteinaceous substances). MP type and amount strongly affected the bacterial community structure, accounting for 54 % of the variance. Due to less bioavailable organics, bacterial community composition within microaggregates was more sensitive to MPs addition compared to macroaggregates. Co-occurrence network analysis revealed that MPs exacerbated competition among bacteria and increased the complexity of bacterial networks. Such effects were stronger for PE than PLA MPs due to the higher persistence of PE in soils. Proteobacteria, Bacteroidetes, Chloroflexi, Actinobacteria, and Gemmatimonadetes were the keystone taxa in macroaggregates, while Actinobacteria and Chloroflexi were the keystone taxa in microaggregates. Proteobacteria, Actinobacteria, and Chloroflexi were the most sensitive bacteria to MPs addition. Overall, both conventional and biodegradable MPs reduced the portion of large and stable aggregates, altering bacterial community structures and keystone taxa, and consequently, the functions.

Precipitation events exhibit a spatiotemporal continuity since they move across both space and time, however, the joint spatiotemporal characteristics of precipitation events are often neglected, and the role of Atmospheric rivers (ARs) and tropical cyclones (TCs) in the events has not been systematically explored. To solve these problems, this study seeks to detect and characterize the three-dimensional (latitude + longitude + time) structures of spatiotemporally contiguous precipitation events, distinguish the heavy events associated with ARs or TCs, and systematically explore the different roles of these events. We do so by combining Forward-in-Time algorithm, an object-based physical event detecting algorithm, with TMPA precipitation estimates to detect spatiotemporally contiguous precipitation events over China, and an AR detection technique considering a combination of fixed lower limit and Integrated Water Vapor Transport percentile threshold is adopted to identify ARs. The heavy events are defined to analyze the differences of the events associated with TCs and ARs as a function of precipitation total, duration, and intensity. Results show that approximately half or more of precipitation events are shorter than 6-hour, and the precipitation total of each event is strongly correlated with maximum intensity and average intensity across China. The heavy events normally occur in southern, center, northern, and southwestern regions, where have approximately 10 to 40 heavy events at each grid. The fraction of heavy events associated with TCs generally increase for events with larger precipitation totals and for events with higher maximum intensity, until all of events are associated with TCs. The percentages of events associated with ARs as well normally increase as precipitation totals and maximum intensity increase up to around 150 mm and 30 mm/h, respectively. Our findings show that the events associated with TCs or ARs exhibit distinct different characteristics, and suggest that the different spatiotemporal dynamics should be sufficient considered in contiguous events analyses in different regions.

Documenting the joint probability of meteorological-hydrological, meteorological-agricultural, and hydrological-agricultural drought can be invaluable for understanding drought evolution under climate change in a high-diversity watershed of south China. Through constructing the edge and joint distribution functions of multi drought indices (SPEI, SPI, SSI, and SWI) based on SWAT and copula methods, we explored the evolution of multi droughts under climate change in the East River basin. During 1997–2017 and 2023–2099, we used logistic, generalized pareto, and normal distributions to construct edge distribution functions of SPEI, SPI, SWI, and SSI. For the four indices, the probability of slight drought increased with rcp2.6, 4.5, 6.0, and 8.5, and it was higher than moderate drought. Also, Clayton, Frank, Gumbel, and Gaussian copula functions were used to construct joint distribution functions of SPEI and SSI, SPEI and SWI, SSI and SWI to quantify their interactions. During 1997–2017, the probability of slight drought was 26.15 to 41.06 %, and the return period changed from 3.8 to 2.4 years. The joint probability of meteorological-hydrological, meteorological-agricultural, and hydrological-agricultural drought in slightly was 24.4 to 31.32 %, 14.95 to 22.63 %, and 6.18 to 22.05 %, respectively. During 2023–2099, the joint probability of droughts in moderately was 3.76 to 14.19 %, and the return period was 7 to 26.6 years. Our results provide a quantitative assessment of single and joint probability of meteorological, hydrological and agricultural drought, which could be used to support watershed water resource management.

The Guangdong–Hong Kong–Macao Greater Bay Area (GBA) is a national initiative aimed at building a world-class city cluster in China and whose trends, socioeconomic drivers of CO2 emissions, and mitigation pathways are of great significance to the high-quality regional economic development. This study compiled the CO2 emission inventories of the GBA from 2000 to 2019 and explored the key drivers of CO2 emissions using the logarithmic mean Divisia index method. The results showed that CO2 emissions in GBA slowed significantly after 2017 and have already been decoupled from gross domestic product (GDP) growth. Economic growth and energy intensity are the major factors driving and inhibiting the increase in GBA’s CO2 emissions, respectively. The energy production and heavy manufacturing sectors have reduced their roles in driving the growth of GBA’s CO2 emissions. GBA achieved remarkable results in low-carbon development through industrial restructuring and upgrading. Industrial upgrades in Shenzhen and Hong Kong and technological advances in Shenzhen, Guangzhou, and Foshan have significantly curbed the growth in the GBA’s CO2 emissions. The heterogeneity of cities in the GBA greatly increases the complexity of formalizing the allocation of emission reduction tasks and developing a roadmap for regional carbon neutrality. Graded emission reduction strategies and carbon peaking and neutrality policy recommendations for GBA cities are proposed. This study provides a scientific basis for the development of an action program for carbon peaking and neutrality in GBA cities and low-carbon development plans for other cities and regions.

Spotted seals, a protected species, face multifaceted threats to their habitat, which in turn impact the closely associated trophic networks. These threats will lead to irreversible structural variations within the ecosystem. Therefore, investigating the topological variability of trophic networks in spotted seals is important. Applying environmental DNA methods, field sample collection was conducted in 2021 during both the sea fishing moratorium period and the fishing period to decode fish diversity. Assessing the current status of fish resources by using the multivariate statistics approach. Applying dietary information establishes the spotted seals’ trophic network. Selecting 12 network indexes to analyze the spatiotemporal patterns of network topological attributes. As a result, about 51 families, and 76 genera species were identified. During the sea fishing moratorium and the fishing period, there are 12 and 18 different food resources available for spotted seals, respectively. The diversity index revealed that the FP had greater species richness and diversity than the SP. Comparatively, the Fishing period exhibited higher species richness and biodiversity, likely influenced by habitat heterogeneity and anthropogenic activities. Additionally, the topological features of networks reflected the high clustering coefficients (CC=0.35) and the proportion of omnivorous species (O≈60%), indicating that the network structure in this region tends to form higher trophic-level clustering patterns, which facilitate the formation of weaker interactions between clusters, enhancing the robustness of the network. The higher connectivity complexity index during the fishing period (SC=12.3) supported that the spotted seal’s trophic network was relatively more stable in this period. Thus, during the fishing period, it is crucial to pay more attention to the intensity of human fishing on mid-to-high trophic-level omnivorous fish resources to ensure the sustainability of these potential food resources for spotted seals. This comprehensive study achieved three key objectives: (a) utilizing eDNA to characterize fish diversity during distinct periods, (b) establishing trophic networks of spotted seals, and (c) discerning topological attributes and spatiotemporal patterns within the ecological network. Overall, this study can provide technical and data support for integrated ecological network management and propose suggestions for protecting and recovering spotted seals.

Intensive human and economic activities in urban areas have had adverse effects on local resources and ecology, leading to a decline in ecological resilience. Enhancing ecological resilience is crucial for improving the urban ecosystem's ability to withstand and recover from external risks. However, quantitative research on urban ecological resilience remains somewhat ambiguous, with many studies lacking comprehensive assessment methods from multiple perspectives. In this study, we established a comprehensive framework to assess urban ecological resilience based on four regime attributes. The study's results indicated the following key findings: The average urban ecological resilience value exhibited a trend of initially declining and then recovering. Cities proposed different approaches when considering and managing social and ecological relationships during the development process. A significant correlation between urbanization levels and ecological resilience was observed, with urban ecological resilience increasing in areas with low urbanization levels and sharply decreasing in areas with high urbanization levels. The findings from this study provide a specific theoretical foundation for decision-makers involved in urban planning and development strategies.

In rivers, riverbeds are considered to have dual properties as a short-term sink and a source of further mobilization for microplastics. To better understand the sources, storage, and fate of microplastics in river systems, this study quantified the formation of microplastic hotspots in riverbeds and seasonal variations in microplastic inventories in riverbeds, especially for small-sized microplastics (

The projection of future ecosystem service (ES) dynamics under SSP-RCP scenarios would be beneficial for the development of effective climate mitigation strategies for policymakers. However, current projection frameworks generally neglect the downscaling of high-resolution climate and land use data, leading to uncertainties in the simulation of ESs under the SSP-RCP scenarios. To address this issue, this study proposes an integrated analysis framework to downscale climate and land use data. We first identified areas of high risk in terms of inadequate water-related ESs in the Pearl River Basin (PRB) of China. Subsequently, we analyzed key socio-environmental factors driving the dynamics of water-related ESs under future SSP-RCP scenarios. The results indicate that 1) water-related ESs in the PRB are expected to show an overall increasing trend, 2) the sub-watersheds located in the downstream is at a higher risk of experiencing insufficient supply capacity for water-related ESs, and 3) under the coupling effects of climate change, land use change, and socio-economic development, drastic changes in future land use are expected to have a stronger impact on watershed ESs than the climate (i.e., global warming). Our work provides valuable insights for policymakers and managers regarding future water and land resource planning. The proposed framework can be integrated with other hydrological or land surface models to project the spatial–temporal evolution characteristics of future watershed ESs with finer temporal resolution.

Aquatic ecosystem restoration is a crucial aspect of ecological management. However, current research tends to concentrate on single factors, such as water quality or biodiversity, rather than ecological restoration strategies based on the characteristics of an ecological network system. Due to the large number of parameters to be considered, the latter approach presents still full of challenges in practical implementation. This study introduces a food web dynamic model that can guide and facilitate aquatic ecological network restoration. The model calculates the network-based interaction relationships of species in the food web, predicting the changes in ecosystem structure and function. We test our food web model by conducting a case study. The food web considered 9 kinds of species nodes, 12 links, and 1 uncertain predator–prey interaction. Our model simulations presented a strong correlation with the measured data (R2 = 0.837). We performed sensitivity analysis on 12 parameters and also conducted link prediction analysis, which revealed that there was no predator–prey relationship between species A and N (A + N = 0). By comparing population dynamics under 3 conditions, we determined that the mass reproduction of nonnative species and the population decline of native species were both related to indirect food web interactions. Finally, we comprised 27 scenarios, including fishing and stock enhancement approaches, to predict the potential restoration effects. The results showed that the fishing approach was more effective in removing alien species when the fishing frequency was shorter. It was also found that selecting catches and releasing native or endangered species back into the environment (F4, F5, F6, and F12) was necessary. On the other hand, the stock enhancement approach was concluded to be effective in increasing the number of native species as long as the frequency of enhancement was high (per 1 year, S1, S2, and S3). However, it was found to be challenging to rely on this approach to reduce the population of nonnative species. This research will enhance the previous studies in terms of (a) including whole species interactions in the ecological network; (b) considering the influence of abiotic factors, such as water quality, terrigenous carrying capacity, shoreline substrate, and hydrological connection in our model; and (c) coupling significant parameters in ecological restoration practices. This research will provide a valuable tool for managing aquatic ecological networks and decision-making suggestions for determining restoration schemes in complex aquatic food webs.

In the current study, to investigate the impacts of the wetness–dryness encountering of the upstream inflow and downstream salt intrusion on the water supply of the Pearl River Delta, we developed a water evaluation and planning (WEAP)-based water resources allocation model to calculate water supply schemes for the Pearl River Delta under 10 different scenarios. The impact of the scenarios on the water supply scheme of the Pearl River Delta was investigated. The results showed that (1) the water shortage of the Pearl River Delta is highly dependent upon the dryness combination of the upstream runoff during the dry period, in particular to the cities at the Pearl River Delta estuary, the water shortages are seriously influenced by saltwater intrusion; and (2) the water transfer projects could alleviate the water supply pressure of the Pearl River Delta when there is an extreme or more dryness encounter of upstream runoff. However, when extreme dryness events are impacting the upstream runoff of the West River, the impact of the water transfer projects is weakened and much of the critical upstream runoff for saltwater suppression cannot be satisfied, which largely impacts water withdrawals at the downstream cities in the Pearl River Delta estuary. HIGHLIGHTS A water evaluation and planning (WEAP)-based water allocation model was developed for coastal urban agglomerations like the Pearl River Delta (PRD).; Water allocation schemes under different scenarios of upstream inflow and downstream salt intrusion were worked out.; The response of the water allocation scheme to the wetness–dryness encountering of the upstream inflow and downstream salt intrusion was revealed.;

The hydrological process in the dry–warm valley of the mountainous area of southwest China has unique characteristics and has attracted scientific attention worldwide. Given that this is an area with fragile ecosystems and intensive water resource conflicts in the upper reaches of the Yangtze River, a systematic identification of its hydrological responses to climate and land use variations needs to be performed. In this study, MIKE SHE was employed and calibrated for the Anning River Basin in the dry–warm valley. Subsequently, a deep learning neural network model of the long short-term memory (LSTM) and a traditional multi-model ensemble mean (MMEM) method were used for an ensemble of 31 global climate models (GCMs) for climate projection. The cellular automata–Markov model was implemented to project the spatial pattern of land use considering climatic, social, and economic conditions. Four sets of climate projections and three sets of land use projections were generated and fed into the MIKE SHE to project hydrologic responses from 2021 to 2050. For the calibration and first validation periods of the daily simulation, the coefficients of determination (R) were 0.85 and 0.87 and the Nash–Sutcliffe efficiency values were 0.72 and 0.73, respectively. The advanced LSTM performed better than the traditional MMEM method for daily temperature and monthly precipitation. The average monthly temperature projection under representative concentration pathway 8.5 (RCP8.5) was expected to be slightly higher than that under RCP4.5; this is contrary to the average monthly precipitation from June to October. The variations in streamflow and actual evapotranspiration (ET) were both more sensitive to climate change than to land use change. There was no significant relationship between the variations in streamflow and the ET in the study area. This work could provide general variation conditions and a range of hydrologic responses to complex and changing environments, thereby assisting with stochastic uncertainty and optimizing water resource management in critical regions.

Ecosystems become increasingly similar to each other, based on species composition. Despite the inevitability of homogenized ecosystems due to global change, few studies have specifically addressed the identification of homogeneous systems in food webs. This study focuses on identifying different patterns of marine food web homogenization by selecting 41 marine food webs and establishing an indicator system. The research classifies the food webs into seven main types based on three different homogenization processes (I, II, III, IV, V, VI, and VII), with approximately 60.1%, 46.3%, and 61% of the homogenization being structural, functional, and resource homogenization, respectively. It highlights the importance of homogenization processes in marine ecosystems, which are mainly driven by interactions between structural and resource homogenization. The research found that Type V exhibited universality in both temporal and spatial dimensions, while Type III also showed universality when the food webs were dominated by resource homogenization. On the other hand, Type I, which was associated with human activities, showed locality when the food web only manifested structural homogenization. Functional homogenization often occurred alongside structural homogenization, as seen in Type IV and Type VII. Yet, when the food web exhibited functional homogenization (Type II), it was directly linked to human activities over the past 20 years. The research aimed to improve the methodology in terms of (a) identifying different food web homogenization patterns; (b) establishing indicators system to quantify food web homogenization; and (c) clarifying the ecological significance of food web homogenization. The study provided a comprehensive understanding of food web homogenization and its associated risks, which could inform nature-based ecosystem management strategies to mitigate the impacts of future climate change.

Climate change and intensive anthropogenic activities have severely challenged the water quality of China’s Pearl River Estuary (PRE). Further investigations into long-term water quality variation and associated driving mechanisms are therefore necessary to support the sustainable development of the PRE’s Greater Bay Area (GBA). This study used remote sensing retrieval to address long-term spatiotemporal chlorophyll-a (Chl-a) variation characteristics in the PRE and the relationship between Chl-a concentrations and socioeconomic/environmental indicators. Three decades of Landsat satellite images and measured data were collected, and a two-band global algorithm was used to retrieve Chl-a concentration data. Results reveal significant spatiotemporal variability in Chl-a concentrations. The space-averaged Chl-a concentration exhibited a slight downward trend during the past three decades, and the multi-year mean value was 5.20 mg/L. Changes to environmental protection policies in recent years have improved overall PRE water quality. The western section of the PRE had the highest Chl-a concentration (i.e., 5.92 mg/L average) while the eastern section had the lowest (i.e., 3.98 mg/L average). This discrepancy was likely caused by the western section’s more intensive industrial activities, resulting in a higher overall wastewater discharge volume. Affected by climatic conditions, winter Chl-a concentrations were evenly distributed while summer concentrations were significantly higher. Additionally, Chl-a concentrations significantly and positively correlated with total phosphorus (TP), total nitrogen (TN), ammonia nitrogen (NH3-N), and the biotic oxygen demand (BOD5). Chl-a concentrations also correlated with external factors (i.e., climate and anthropogenic activities). Among these factors, industrial wastewater discharge and the proportion of primary industries in coastal cities significantly and positively correlated with water quality. This study is intended to help direct water quality improvement management and urban sustainable development in the GBA.

Study region: A deep reservoir between Xiluodu (XLD) dam and Xiangjiaba (XJB) dam, located in the lower reaches of Jinsha River. Study focus: Dam construction, especially high dam construction, normally caused the supersaturated total dissolved gas (TDG) downstream of the dam and reduced the flow velocity of the reservoir, which hindered the safe migration of fish. In this research, an eco-friendly reservoir operation model with a multi-objective optimization method was established to reduce supersaturated TDG level and increase reservoir flow velocity in this key ecological zone to restore fish migration pathways. The model consisted of three modules: supersaturated TDG prediction module, reservoir velocity prediction module and multi-objective optimization module. In order to re-establish suitable migratory habitat for fish migration, ecological constraints were added to the reservoir multi-objective operational method including minimum supersaturated TDG level and maximum reservoir flow velocity. And, a 2-D TDG transport diffusion model was adopted to verify the effectiveness of eco-friendly reservoir operation results. The study aims to re-establish fish migration channel of large reservoirs by using eco-friendly reservoir operation methods. New hydrological insights: The proposed reservoir operation model was efficient in reducing the maximum residence time of supersaturated TDG and increasing the reservoir flow velocity. The area between Xiluodu (XLD) dam and Xiangjiaba (XJB) dam was used as a studying case to analyze the usability of the developed method. The best simulation result was obtained under the scenario with comprehensive consideration of power generation and ecological objectives, and the maximum residence time of 140% supersaturated TDG level was 4 h, which was consistent with the designed worst Mean Lethal Time (LT50) of 4 h for fish. The worst simulation result was obtained in the pattern targeting power generation only, with a maximum residence time of 8 h for supersaturated TDG level at 140%, which exceeded the corresponding LT50 of fish. Under all three scenarios, the XLD hydropower station was generating at full capacity and the minimum flow velocity in the XJB reservoir would be above 0.2 m/s. Overall, this study provides an opportunity to reconstruct the fish migration habitat in the reservoir area.

The rapid expansion of aquaculture in coastal areas is typically associated with ecological negligence and low water quality owing to the economic exploitation of these areas. However, evaluation of these water bodies tends to be laborious, time-consuming, and costly. Therefore, to overcome the limitations of field surveys, in this study, we evaluated the water quality of the cultured water in the Beibu Gulf of Guangxi, obtained spectral reflectance by unmanned aerial vehicle with multispectral sensors, and constructed inverse models of 11 water quality parameters, namely, ammonia nitrogen (NH3-N), chemical oxygen demand (COD), active phosphate (PO4−), dissolved oxygen, nitrate nitrogen (NO3-N), nitrite nitrogen (NO2-N), inorganic nitrogen, total nitrogen, total phosphorus, suspended solids (SS), and chlorophyll a (chl-a), based on the partial least squares method to invert the water quality distribution of regional aquaculture. Furthermore, we compared the retrieval accuracy of different water quality parameters. The following results were obtained: 1) the constructed model’s results showed that the retrieval models for COD, NO3-N, SS, and chl-a had better accuracy compared with those of other parameters; 2) application of the model to the validation set data yielded a correlation coefficient of 0.93 between the measured and predicted SS values, with a mean absolute error of prediction of 4.65 mg L−1; this parameter constructed the best prediction model. According to the validation set results, the correlation coefficients of chl-a, COD and NO3-N are all greater than 0.8, which had better performance effects compared with the remaining models, which are 0.87, 0.86, and 0.81 respectively. This study provides a reference for remote sensing monitoring of water quality in mariculture in cloudy and rainy areas.

Although numerous studies have investigated environmental occurrence, human exposure, and toxic effects of bisphenol analogues including bisphenol A (BPA), little is known about closely related chemical classes namely, bisphenol A diglycidyl ethers (BADGEs) and novolac glycidyl ethers (NOGEs), which are widely used in a variety of industrial and consumer products. In this review, we compiled available information on production and usage, analytical challenges, dietary and non-dietary sources of exposure, occurrence in human and environmental matrices, toxicity, and regulations on BADGEs and NOGEs. Human exposure to BADGEs and NOGEs is widespread, with exposure doses in the range of several hundreds of nanograms (ng) to few micrograms (μg) per kilogram (kg) body weight (bw) per day (d) from diet and

In this study, a new concept concerning comprehensive characteristics of water resources utilization as an index for risk modeling within the water allocation management model is proposed to explore the tolerance of unbalanced allocation problem under the water–energy nexus. The model is integrated with interval two-stage stochastic programming for reflecting system uncertainties. These uncertainties are associated with the industrial production feature and the decision-making process. With respect to the water–energy nexus, energy proposed is mainly focused on the consumption intensity of water purification and transportation from different water sources. The developed model is applied for industrial water resources allocation management in Henan province, China. Multiple scenarios related to disparate energy consumption control and the comprehensive risk levels are simulated to obtain a reasonable trade-off among system profit, comprehensive risk, and energy consumption. The results indicated that the strict comprehensive risk management or energy consumption control measures could cause damage to system benefit owing to decreasing the flexibility of industrial water resources distributions, and the preliminary energy consumption or the comprehensive risk control would be beneficial to moderate the conflict between industrial sectors and water resources, and accelerate industrial structure transformation in the future. HIGHLIGHTS A comprehensive risk-oriented industrial water resources management model is proposed.; Uncertainties are reflected as stochastic and interval information.; Energy–water nexus is a constraint index for water purification and transportation.; The tolerance of unbalanced allocation problem is explored.; Trade-off among system profit, comprehensive risk, and energy consumption is analyzed.;

Floating offshore wind power, an emerging technology in the offshore wind industry, has attracted increasing attention for its potential to cooperate with other renewable energies to decarbonize energy systems. The environmental effects of the floating offshore wind farm in deep-sea areas should be considered, and methods to enhance the low-carbon effect should be devised. There have been a few studies assessing the environmental effects of the floating offshore wind farm, but the scales of these studies were relatively small. This study evaluated the environmental impacts of a floating wind farm with 100 wind turbines of 6.7 MW using life cycle assessment (LCA) method, based on the Chinese core life cycle database. Results showed that the carbon footprint of the wind farm was 25.76 g CO2-eq/kWh, which was relatively low in terms of global warming potential. Additionally, the floating offshore wind farm contributed most to eutrophication potential. A ± 20% variation in steel resulted in a ±3% to ±15% variation in the indicator score of each environmental category, indicating that the environmental performance of the wind farm was mainly influenced by this parameter. Moreover, scenario analysis showed that electric arc furnace routes can reduce the cumulative greenhouse gas emissions from upstream process of the floating offshore wind farm by 1.75 Mt CO2-eq by 2030. Emission reduction of the steel industry will further reduce the carbon footprint of the floating offshore wind farm. In the future, more baseline data need to be collected to improve the reliability of LCA. The effects of the floating offshore wind farm on marine ecology and atmospheric physical characteristics remain to be investigated in depth.

The resilience of the urban ecological network is an indispensable aspect of reflecting the recovery capacity after the external risk shock. Improving the resilience of the ecological network is conducive to enhancing the ecological benefits. However, the current studies are lack of resilience evaluation from a comprehensive perspective. Thus, in this study, taking three typical urban agglomerations as cases, a comprehensive evaluation framework was proposed to assess ecological network resilience. First, we selected the comprehensive reserve as ecological sources and combined them with ecological corridors to construct the ecological network. Then we evaluated the resilience of ecological networks from the perspectives of robustness and redundancy. Finally, we analyzed the resilience of the network under different importance nodes failed. The results showed that (1) the average values of the comprehensive reserve value (CRV) in three urban agglomerations were over than 0.8. (2) the resilience of ecological networks in three urban agglomerations was blow the optimal value throughout during the period from 1985 to 2020. (3) the resilience change trends of multiple urban agglomerations were significant differences after removing certain important nodes, indicating the current ecological network is redundant. The research will help to improve the evaluation of urban ecological resilience and enhance the improvement of sustainable urban management and ecological restoration.

Neonicotinoid insecticides (NEOs) are widely used in many urban regions. Studies on NEOs residues in urban tidal streams and the associated ecological risks are limited. In this study, the occurrence, spatiotemporal distribution, and ecological risks of seven selected NEOs in the Wuchong Stream in Guangzhou, China were investigated. Moreover, the correlation between typical urban factors and the ecological risk of NEOs was discussed. In the Wuchong Stream, the concentrations of NEOs in the water samples ranged from 0.97 to 175.92 ng. L-1 in the dry season and 3.15 to 312.92 ng. L-1 in the wet season.The most commonly used neonicotionoids were acetamiprid and imidacloprid in the Wuchong Sream basin. The concentrations of NEOs in the midstream were higher than that in the downstream and upstream. The results of the ecological risk indicated that NEOs were likely to biologically impair the urban stream ecosystem, especially in the dry season. For three typical aquatic organisms, the current concentrations of NEOs posed a significant threat to aquatic insects. Compared to other urban factors, residentidal district and farmland area were the main socioeconomic factors affecting the ecological risk of NEOs in the Wuchong Stream basin. Therefore, the correct and reasonable application of NEOs and continuous improvement of the applicant methods can reduce the environmental risks of urban streams.

High-strength alterations in the water level due to extreme climate change and increased anthropogenic activities have implications for methane (CH4) and carbon dioxide (CO2) emission variations in shallow lakes. However, the consistency of the carbon emission flux in response to water-level fluctuations and temperature is still unclear. Here, we evaluated the water depth (WD) on the magnitude and variation sensitivity of CH4, CO2, and GHG, and then the temperature dependence of carbon emissions was estimated at different water levels. The water depth threshold indicated a maximum CH4 (97.5 cm) and CO2 (10 cm), resulting in a water depth threshold of GHG at 54.6 cm. Inside the whole WD, the effect of rising water depth on CH4, CO2 and GHG sensitivity shifted from a positive effect to a negative effect at a WD of 97.5 cm. And CH4, CO2 and GHG in 10 cm

The impact of waves on the morphological changes of sheltered mudflats is less well studied compared to that on open flats. To investigate the sensitivity of low-energy sheltered mudflats to hydrodynamics such as waves, we carried out in situ measurements of bed level, currents, and waves on the middle flat of a sheltered mudflat in a bay in southern China. Two 1-month measurements, March 26–26 April 2021, and July 8–8 August 2021, were performed for repetition. We found that the sheltered system was not as stable as it appeared. The maximum intratidal bed-level variation, ΔZ, was

High-intensity human activities have caused dramatic changes in land-use structure in Guangzhou. It is essential to understand the spatiotemporal dynamics of land use and the induced ecological risks. In this research, a framework was developed for landscape ecological risk (LER) prediction based on a patch-generating land use simulation (PLUS) model through incorporating analysis of land expansion strategies, CA model based on multi-type random patch seeds and LER assessment model. The results showed: 1) the urbanization process of Guangzhou was obvious in the past 20 years. Proximity to railways, highways, and secondary roads have the primary impact on the expansion of cultivated land, grassland and construction land, respectively, 2) Guangzhou's future urban expansion is inevitable based on the PLUS model prediction, 3) during 2000–2020, the overall LER in Guangzhou was at a relatively low level. The higher ecological risk area was mainly distributed in the southern sea area, and 4) from 2020 to 2040, Guangzhou's higher ecological risk areas are on an overall decreasing trend under three scenarios. This research can provide a reference for the planning of regional ecological environmental protection and sustainable development of land resources, as well as LER prediction.

As amplified by climate changes and anthropogenic activities, mobile generalist species have been dominating the food web succession in a closed ecosystem. However, compared to marine ecosystem, the internal mechanism of generalist species affecting freshwater community were paid less attentions. In this study, the association of mobile generalist species and native apex predator was identified in Chenghai Lake, where was taken as the study case of a closed ecosystem to create the succession dynamic of food web from 1983 to 2019. Weighted food web analysis (WFWA) approach was applied to determine keystoneness and interaction strength of each species node, which is achieved through the quantification of the direct impacts on food web nodes from its biomass. As shown in the results, in the food web of 1983, there were nearly 25 nodes and 80 links, while in 2009, there were 22 nodes and 58 links, however, in 2019, there were 16 nodes and 25 links. In 2019, the three original specialized apex predator nodes were disappear. The keystoneness of each species was − 0.048, − 0.109 and − 0.742 respectively. During the nearly 40-year succession, including 13 native species had gone within 10 years, which were difficult to find its trace. The omnivorous alien species have occupied an absolute dominant niche, exhibiting the characteristics of mobile generalist species in 2019. The keystoneness of these species was − 0.194, − 0.235 and − 0.236 respectively. In general, from 1983 to 2019, the nodes have decreased by 36% and links have dropped by 68.75% on average in Chenghai Lake food web. In this study, (a)revealing the associations between mobile generalist species and native apex predators; (b) distinguishing the keystone species affecting food web structural; (c) developing food web analysis approach and determining the succession dynamic of Chenghai Lake. These findings improve the understanding of potential impacts from mobile generalist species in closed ecosystem.

A new species of Pachypaederus Fagel, 1958, P. kongshuhensis Li, sp. nov., is described from Yunnan Province, China. This species represents the third member of the genus from the Oriental region. Color plates of the habitus, labrum, mandibles, sternites VII–IX of the male and female, as well as the aedeagal structures are provided. A key to Oriental Pachypaederus species is provided.

Two new species of the genus Pseudolathra Casey, 1905 from mainland China are reported in this paper, namely Pseudolathra gansuensis Li & Zhou, sp. nov. and P. assingi Li & Zhou, sp. nov. This genus is reported for the first time from Gansu Province, Northwest China. Both species are described in detail and supplemented with color plates of normal light photos of the habitus, sternites VII–IX and details of aedeagal structures in different views.

Perturbations of the gut microbiome are often intertwined with the onset and development of diverse metabolic diseases. It has been suggested that gut microbiome perturbation could be a potential mechanism through which environmental chemical exposure induces or exacerbates human diseases. Microplastic pollution, an emerging environmental issue, has received ever increasing attention in recent years. However, interactions between microplastic exposure and the gut microbiota remain elusive. This study aimed to decipher the responses of the gut microbiome upon microplastic polystyrene (MP) exposure by integrating 16S rRNA high-throughput sequencing with metabolomic profiling techniques using a C57BL/6 mouse model. The results indicated that MP exposure significantly perturbed aspects of the gut microbiota, including its composition, diversity, and functional pathways that are involved in xenobiotic metabolism. A distinct metabolite profile was observed in mice with MP exposure, which probably resulted from changes in gut bacterial composition. Specifically, untargeted metabolomics revealed that levels of metabolites associated with cholesterol metabolism, primary and secondary bile acid biosynthesis, and taurine and hypotaurine metabolism were changed significantly. Targeted approaches indicated significant perturbation with respect to the levels of short-chain fatty acids derived from the gut microbiota. This study can provide evidence for the missing link in understanding the mechanisms behind the toxic effects of microplastics.

DNA-based taxon identification is improving the assessment and management of biodiversity in rivers. However, the lack of comprehensive DNA barcode reference libraries and globally highly unequal coverage are still hindering the application prospects of this method worldwide. Here, we analyzed the COI barcode gap in two reference libraries, Barcode of Life Data Systems (BOLD) and NCBI GenBank, with a focus on three aquatic animal groups (freshwater fish, aquatic insects and molluscs) in Chinese rivers. Our data show gaps in barcode coverage (e.g., organisms without barcodes) of ca. 40–70% of taxa in these groups in the BOLD or NCBI GenBank database, respectively. These gaps can rise even further if the barcode thresholds are set to contain at least five reference sequences per taxon. Furthermore, most barcodes are from non-local samples, and only 14.4% (BOLD) and 28.8% (NCBI GenBank) of reference sequences were from organisms sampled in China, respectively. The pairwise genetic distance of local barcodes is 3 to 5 times lower than non-local barcodes, indicating that the latter may not be a good substitute. When looking at individual catchments, ca. 60% of the potentially occurring aquatic species have one or more barcodes, yet the barcode coverage varies slightly across ten major river catchments, ranging from 54.3% (Liao River basin) to 68.2% (Huai River basin). The taxa Salmoniformes and Perciformes in freshwater fish, Odonata and Diptera in aquatic insects, and Bivalvia in molluscs have the best barcode coverage in most catchments (mean coverage >70%). This study gives the first overview and current status of barcode reference libraries of three major aquatic animal groups in Chinese rivers. Our results will help to better interpret current metabarcoding studies from China, and also provide a basis to develop a strategy of filling the gaps in the reference libraries of aquatic species in China.

The complete mitochondrial genome of Aleochara postica Walker, 1858 was determined in this study. It is 15,473 bps in length, containing 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a 778 bp A + T-rich control region. Most PCGs use the conventional ATN start codon, except for cox1 and nad1. Two genes (cox1 and cox3) use single T residue as stop codon rather than the routinely used TAA or TAG. All tRNAs, except for TrnS1, exhibit the cloverleaf secondary structure. ML phylogenetic analysis using 13 PCGs of 52 beetle species indicated that A. postica was clustered with other members of the subfamily Aleocharinae as conventional taxonomy predicted.

A new species, Queskallion saetosum sp. nov., is described herein from Sichuan Province, China. It is diagnosed from a closely related species, Q. tangi Smetana, 2015. Color images and line drawings of the adult of the new species, as well as its genitalia are provided. In addition, a checklist of species, an updated key to species and a geographical distribution map of all known species in the genus Queskallion Smetana are included.

A male of the very rare and phylogenetically puzzling species, Quelaestrygon puetzi Smetana, 1999, is described for the first time based on a single specimen from Sichuan Province, China. High quality color images and line drawings of the male external and genitalic traits are provided.

Lasiochira wuzhishanensis Yin, sp. nov. is described herein from the island province of Hainan, China. It is diagnosed from a similar species, Lasiochira jianfengensis Yin, Wang & Park, 2014. Both species are sympatric in Hainan province, but the latter is also known in northern Vietnam. Lasiochira pallidiptera Yin, Wang & Park, 2014 is recorded for the first time from China. Color images of the adults and genitalia of the above three species are provided. In addition, a checklist and a geographical distribution map of all species of Lasiochira Meyrick are included.

Agri-products have an impact on food security, ecology protection, and crucial strategic deployment. With this respect, the economic value of agri-products should be paralleled with a non-monetary assessment of ecological value for humans. This study set up an emergy-based life-cycle assessment (Em-LCA) framework to calculate the ecosystem service (ES) and ecosystem dis-services (EDS) that was applied to six typical crops, exploring the implementation path of the agricultural eco-product value. The results showed the agriculture system mainly depends on non-renewable resources. EDS generated by China’s agri-products is higher than the ES provided by them. Nevertheless, there is a low correlation between the current price of agri-products and their greenness, but, economic value presents a rising trend with agri-product greenness increasing. Further to discussing effective approaches to sustainable agriculture, it can be seen that 1) sustainable agriculture will lead to increased greenness, but it is impossible to improve greenness indefinitely. 2) Improving greenness is an effective way to implement ecological value, another way to preserve and raise ecological value is to reduce EDS generation. 3) Reducing energy consumption leads to a decrease in EDS but it is not an appropriate way to achieve sustainable development. These findings provide meaningful suggestions for decision-makers to realize the ecological value of agri-products.

Neonicotinoid insecticides (NEOs) are commonly used to prevent unwanted insects in urban fields. Degradation processes have been one of the important environmental behaviors of NEOs in an aquatic environment. In this research, hydrolysis, biodegradation, and photolysis processes of four typical NEOs (i.e., thiacloprid (THA), clothianidin (CLO), acetamiprid (ACE), and imidacloprid (IMI)) were examined through the adoption of response surface methodology–central composite design (RSM-CCD) for an urban tidal stream in South China. The influences of multiple environmental parameters and concentration levels on the three degradation processes of these NEOs were then evaluated. The results indicated that the three degradation processes of the typical NEOs followed a pseudo-first-order reaction kinetics model. The primary degradation process of the NEOs were hydrolysis and photolysis processes in the urban stream. The hydrolysis degradation rate of THA was the highest (1.97 × 10−5 s−1), and that of CLO was the lowest (1.28 × 10−5 s−1). The temperature of water samples was the main environmental factor influencing the degradation processes of these NEOs in the urban tidal stream. Salinity and humic acids could inhibit the degradation processes of the NEOs. Under the influence of extreme climate events, the biodegradation processes of these typical NEOs could be suppressed, and other degradation processes could be further accelerated. In addition, extreme climate events could pose severe challenges to the migration and degradation process simulation of NEOs.

Commonalities and asynchronous experiences of realizing zero-waste of water, energy, and food resources between the world and China have critical global importance to support sustainable development, especially for Guangdong-Hong Kong-Macao Greater Bay Area (GBA) urban agglomeration. In this study, a comprehensive assessment framework for the zero-waste city was proposed to evaluate zero-waste construction in the world (e.g., San Francisco, New York, and Tokyo) and China (e.g., Beijing, Shanghai, and GBA) from the perspective of water, energy, and food. The results showed that the zero-waste construction level of the GBA cities was weaker than that of the benchmark city and other world-class cities. The average score of the GBA cities was the lowest, 2.5% lower than the benchmark city and 11.8% lower than other world-class cities. Macao had apparent advantages in the social-economic and ecological-environment system, while the Pearl River Delta cities were considerably better than Macao and Hong Kong in the water and food systems. Future work could improve the level of zero-waste construction by learning from foreign zero-waste cities’ advanced experience, increasing efforts to promote the implementation of a circular economy, and building an all-around government sharing mechanism with public participation.

Summary: The deep-sea environment creates the largest ecosystem in the world with the largest biological community and extensive undiscovered biodiversity. Nevertheless, these ecosystems are far from well known. Deep-sea equipment is an indispensable approach to research life in extreme environments in the deep-sea environment because of the difficulty in obtaining access to these unique habitats. This work reviewed the historical development and the state-of-the-art of deep-sea equipment suitable for researching extreme ecosystems, to clarify the role of this equipment as a promoter for the progress of life in extreme environmental studies. Linkages of the developed deep-sea equipment and the discovered species are analyzed in this study. In addition, Equipment associated with researching the deep-sea ecosystems of hydrothermal vents, cold seeps, whale falls, seamounts, and oceanic trenches are introduced and analyzed in detail. To clarify the thrust and key points of the future promotion of life in extreme environmental studies, prospects and challenges related to observing equipment, samplers, laboratory simulation systems, and submersibles are proposed. Furthermore, a blueprint for the integration of in situ observations, sampling, controllable culture, manned experiments in underwater environments, and laboratory simulations is depicted for future studies.

In this research, an integrated approach is developed through the incorporation of systems dynamics (SD), catastrophe progression (CP), and coupled coordination degree (CCD) analysis within a general modelling framework. The developed SD-CP-CCD is then employed to simulate and evaluate relationships among the water-energy-food (WEF) and the economic systems. It will improve traditional methods for WEF nexus analysis through a) incorporating urban WEF connections and changes into the cross-system coupling analysis framework, b) evaluating its coordination with economic growth and a multi-scale and regional disparity, and c) promoting policy recommendations to ensure the guarantee of urban WEF under economic growth. The approach is then verified through WEF nexus system of Urban Agglomerations of Pearl River Delta City Cluster (PRDCC) in China. Temporal and spatial characteristics of CCD in the region were analyzed. The results revealed their performance in cities with multiple economic backgrounds. Also, the fragile factors of each city were reflected by multi-scale exploration. Regional inequality and spatial agglomeration effects were considered. The results showed that CCD has noticeable temporal and spatial differences. Geographically, CCD varied from uncoordinated to high-level coordination. The eastern cities were much better coordinated than the western cities. Due to the increasing pressure of population and economic growth in the future, the upward trend of CCD would occur in most cities. The vulnerability factors of each city were explored. Simultaneously, apparent spatial inequality and agglomeration patterns were observed, with a downward trend over time. The temporal and spatial patterns of CCD revealed in this study indicated that PRDCC policymakers should formulate policies that suit the characteristics of cities and reduce the targeted regional imbalances.

Climate warming and eutrophication caused by anthropogenic activities strongly affect aquatic ecosystems. Submerged macrophytes usually play a key role in shallow lakes and can maintain a stable clear state. It is extremely important to study the effects of climate warming and eutrophication on the growth of submerged macrophytes in shallow lakes. However, the responses of submerged macrophytes to climate warming and eutrophication are still controversial. Additionally, the understanding of the main pathways impacting submerged macrophytes remains to be clarified. In addition, the influence of seasonality on the growth responses of submerged macrophytes to climate warming and eutrophication requires further elucidation. In this study, we conducted a series of mesocosm experiments with four replicates across four seasons to study the effects of rising temperature and nutrient enrichment on the biomass of two submerged macrophytes, Potamogeton crispus and Elodea canadensis. Our results demonstrated the seasonality and species specificity of plant biomass under the influence of climate warming and eutrophication, as well as the main explanatory factors in each season. Consistent with the seasonal results, the overall results showed that E. canadensis biomass was directly increased by rising temperature rather than by nutrient enrichment. Conversely, the overall results showed that P. crispus biomass was indirectly reduced by phosphorus enrichment via the strengthening of competition among primary producers. Distinct physiological and morphological traits may induce species-specific responses of submerged macrophytes to climate warming and eutrophication, indicating that further research should take interspecies differences into account.

Coastal wetlands such as salt marshes have been increasingly valued for their capacity to buffer global climate change effects, yet their long-term persistence is threatened by environmental changes. Whereas, previous studies largely focused on lateral erosion risk induced by stressors like sea level rise, it remains poorly understood of the response of lateral expansion to changing environments. Seedling establishment is a key process governing lateral marsh expansion as seen in many coastal regions such as Europe and East Asia. Here, we evaluate mechanistically the response of seed bank dynamics to changing physical disturbance at tidal flats, using the globally common coastal foundation plant, cordgrass as a model. We conducted a large-scale field study in an estuary in Northwest Europe, where seed bank dynamics of cordgrass in the tidal flats was determined and linked to in situ hydrodynamics and sediment dynamics. The results revealed that wave disturbance reduced the persistence of seeds on the surface, whereas amplified sediment disturbance lowered the persistence of both surface and buried seeds. Overall, this indicates that increasing storminess and associated sediment variability under climate change threatens seed bank persistence in tidal flats, and hence need urgently be incorporated into models for long-term bio-geomorphological development of vegetated coastal ecosystems. The knowledge gained here provides a basis for more accurate predictions on how climatically driven environmental changes may alter the fitness, resilience and persistence of coastal foundation plants, with significant implications for nature-based solutions with coastal vegetation to mitigate climate change effects.

Nutrient enrichment commonly promotes phytoplankton biomass, while the presence of macrophytes can mitigate the promotion effects of nutrient loading. However, the existing studies have seldomly focused on the impacts of macrophytes on the phytoplankton’s physiological responses to nutrient availability. To fill this gap, a 30-day mesocosm experiment was conducted across a four-level nutrient gradient to investigate the variations of the phytoplankton biomass and physiological status (represented by Chl-a and Fv/Fm, respectively) in the absence and presence of macrophytes. Among the eight treatments, the performances of green algae and diatoms were compared as they accounted for >95% of the total phytoplankton biomass. Our results showed that although the presence of macrophytes did not inhibit Chl-a and Fv/Fm of green algae and diatoms, it significantly changed the effects of nutrients on Chl-a and Fv/Fm of green algae and diatoms. Structural equation model (SEM) indicated that the causal relationships between environmental variables and Chl-a/Fv/Fm of green algae and diatoms differed in the absence and presence of macrophytes. When macrophytes was absent, Chl-a and Fv/Fm of green algae and diatoms were significantly affected by electrical conductivity, TN, and Kd/salinity. These explanatory variables accounted for 52% and 84% of the variations in Chl-a of green algae and diatoms, and 10% and 21% of the variations in Fv/Fm of green algae and diatoms. When macrophytes was present, Chl-a and Fv/Fm of green algae and diatoms were significantly affected by electrical conductivity, TN, TP, and pH. These explanatory variables accounted for 39% and 77% of the variations in Chl-a of green algae and diatoms, and 43% and 36% of the variations in Fv/Fm of green algae and diatoms. Overall, nutrient availability and subsequently environmental changes caused more variations in phytoplankton Chl-a than variations in phytoplankton Fv/Fm, and more variations in diatoms than variations in green algae. Our results suggested that the response mechanism of phytoplankton to nutrient availability varied between the presence and absence of macrophytes, as well as between green algae and diatoms. Therefore, simultaneous evaluation of the biomass and physiological status of different phytoplankton groups can provide broader insight into the interaction mechanisms between macrophytes, nutrients and phytoplankton.