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Understanding and predicting the ecological status of urbanized rivers is crucial for their restoration and management. However, the complex and nonlinear nature of ecological responses poses a challenge to the development of predictive models. Here, the study investigated and predicted the status of eukaryotic plankton communities in urbanized rivers by coupling environmental DNA metabarcoding, the alternative stable states theory, and supervised machine learning (SML) models. The results revealed two distinct states of eukaryotic plankton communities under similar environmental conditions: one state was characterized by the enrichment of a diverse phytoplankton population and the high relative abundance of protozoa, whereas the alternative state was characterized by abundant phytoplankton and fungi with an associated risk of algal blooms. Turbidity was identified as a key driver based on the SML model and Mantel test. Potential analysis demonstrated that the response pattern of eukaryotic plankton communities to turbidity was thresholds with hysteresis (Threshold1 = 17 NTU, Threshold2 = 24 NTU). A reduction in turbidity induced a regime shift in the eukaryotic plankton community toward an alternative state associated with a risk of algal blooms. In the prediction of ecological status, both SML models showed excellent performance (R2 > 0.80, RMSE < 0.1, Kappa > 0.70). Additionally, SHapley Additive exPlanations analysis identified turbidity, chlorophyll-a, chemical oxygen demand (COD), ammonia nitrogen and green algae's amplicon sequence variants as crucial features for prediction, with turbidity and COD showing a synergistic effect on ecological status. A framework was further proposed to enhance the understanding and prediction of ecological status in urbanized rivers. The obtained results of this study demonstrated the feasibility of using SML models to predict and explain the ecological status of urbanized rivers with alternative stable states. This provides valuable insights for the application of SML models in the restoration and management of urbanized rivers.

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Highly urbanized coastal ecosystems are vital in the global carbon budget. However, there are limited researches on carbon flux gradients in these nearshore areas, considering both natural and anthropogenic influences. Through on-site measurements and field samplings during wet-to-dry season in 2023, this study investigated spatial variations and factors affecting carbon fluxes, focusing on the impacts of salinity and eutrophic status in five geographically connected coastal waters of the Guangdong-Hong Kong-Macau Greater Bay Area (GBA). By estimating carbon exchange at land-sea-air interface, dominant processes in carbon dynamics were identified as well. Results showed that partial pressure of CO2 (pCO2) varied from 391 to 2290 µatm, and sea-air CO2 exchange fluxes (FCO2) ranged from -3.07 to 70.07 mmol m-2 d-1, indicating significant geographical distinctions among five coastal waters of the GBA. The total carbon transport from rivers to these nearshore waters was approximated at 6.44 Tg C yr-1, with the Pearl River (PR) contributing 99.7%, primarily in dissolved forms. Atmospheric CO2 release was calculated at 0.29 Tg C yr-1 for studied five coastal waters, primarily as carbon sources, except for Dapeng Bay (DPB) as a sink. CO2 emissions inversely correlated with salinity, yet positively with eutrophication status, particularly in river-dominated estuaries. Moreover, CO2 flux decreased 23 times as eco-status shift from eutrophic to non-eutrophic. River plumes, terrestrial pollutant inputs, and economic structure were underlying drivers, influencing carbon species concentrations and fluxes. Elevated CO2 concentrations in eutrophic coastal waters were mainly attributed to terrestrial carbon and nutrients inputs, supporting active biological respiration and microbial decomposition. Conversely, carbon dynamics potentially depend on the balance of respiration and photosynthesis in non-eutrophic coastal waters. This study offers high geographic precision and specificity of carbon species, and provides land-sea integration insight to understand carbon dynamic mechanisms, promoting advancements in water quality management and climate mitigation.

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The impacts of landscape patterns on river water quality are commonly acknowledged, but understanding the complex processes by which landscape patterns affect water quality is still limited, especially in densely populated urban areas. Exploring the mechanisms through which landscape characteristics influence water quality changes in urbanized rivers will benefit regional water resource protection and landscape-scale resource development and utilization. Utilizing daily water quality monitoring data from rivers in the urbanized area of the Pearl River Delta in 2020, our research employed canonical analysis and partial least squares structural equation modeling (PLS-SEM) to explore the processes and mechanisms of the influence of urbanized river landscape patterns on surface water quality. The results indicated that total nitrogen (TN) was the critical indicator limiting the water quality of rivers in the Pearl River Delta. The landscape composition and configuration indexes exhibited non-linear variations with scale, and the landscape fragmentation was higher closer to the river. Landscape patterns had the most significant influence on water quality under the characteristic scale of a 5.50 km circular buffer zone, and landscape composition dominated the change of water quality of urbanized rivers, among which 30.64% of the percentage patch area of construction (C_PLAND) contributed 46.40% to the explanation rate of water quality change, which was the key landscape index affecting water quality. Moreover, landscape patterns had a higher interpretive rate of 39.29% on water quality in the wet season compared to 36.62% in the dry season. Landscape composition had an indirect negative impact on water quality, with a value of 0.47, by affecting the processes of runoff and nutrient migration driven by human activities, while landscape configuration had an indirect negative impact on water quality, with a value of 0.11. Our research quantified the impacts of landscape patterns driven by human activities on surface water quality and proposed management measures to optimize the allocation of landscape resources in riparian zones of urbanized rivers. The results provide a scientific basis for water quality management and protection in urbanized rivers.

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Understanding the genetic makeup of key coral species is vital for effective coral reef management, as heightened genetic diversity directly influences long-term survival and resilience against environmental changes. This study focused on two widespread Indo-Pacific branching corals, Pocillopora damicornis (referred as Pocillopora cf. damicornis (as identified only morphologically) and Seriatopora hystrix, by genotyping 222 and 195 colonies, respectively, from 10 sites in the northern Gulf of Eilat, Red Sea, using six and five microsatellite markers, respectively. Both species exhibited low observed heterozygosity (0.47 for P. cf. damicornis, 0.32 for S. hystrix) and similar expected heterozygosity (0.576 for P. cf. damicornis, 0.578 for S. hystrix). Pocillopora cf. damicornis showed minimal deviations from Hardy-Weinberg equilibrium (HWE) and low but positive F values, indicating high gene flow, while S. hystrix exhibited higher diversion from HWE and positive F values, suggesting isolation by distance and possible non-random mating or genetic drift. As the Gulf of Eilat undergoes rapid urbanization, this study highlights the anthropogenic impacts on the population genetics of key ecosystem engineering species and emphasizes the importance of managing genetics of Marine Protected Areas while implementing active coral reef restoration. The differences in reproductive traits between the two species (S. hystrix being a brooder, while P. cf. damicornis a broadcast spawner), underscore the need for sustainable population genetics management of the coral reefs for the future and resilience of the coral reef ecosystem of the northern Red Sea region.

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The present study aimed to report the morphometric and hematological indices and genotoxicity of a free-life population of D'Orbigny's slider turtles (Trachemys dorbigni) living in an urban area in Southern Brazil. For that, 16 specimens were randomly captured in an urban canal that receives irregular releases of wastewater. Biometrics and external visual changes were analyzed, such as turtle shell deformities, and the presence of parasites. Blood samples were collected to evaluate the hematological profile and the presence of micronuclei and other erythrocyte nuclear abnormalities as potential mutagenic and genotoxic effects. Water physicochemical parameters were also measured. Organisms with ectoparasites (31.25%) and small carapace deformations (56.25%) were observed, but maximum carapace length and weight were considered normal for the species according to the literature. The blood profile indicated low hemoglobin and hematocrit and a high number of total leukocytes, particularly eosinophils which characterize parasitic infections. A frequency of 0.12% for the micronucleus was considered basal, but the frequency of other erythrocyte abnormalities was evident, mainly of blebbed nuclei (63.79%), indicating chromosomal damage in the early stage. The results of this study suggest that natural populations of chelonian inhabiting urbanized areas are impacted by anthropogenic activities in the surrounding environment. Furthermore, it provides comprehensive data which can serve as a comparative model for environmental monitoring studies involving turtles.

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Urbanizations and industrializations may accelerate the contamination and deterioration of groundwater quality. This study aimed to evaluate the quality and potential human health risks associated with shallow groundwater in Shenzhen, China, a city characterized by high levels of urbanization and industrialization. The hydrochemistry characteristics, water quality levels, and human health risks of main ions, nutrient elements, and metals in 220 samples collected from Maozhou River Basin (MRB) located in the northwest of Shenzhen were investigated. It showed that chemical constituents of the groundwater were further complicated by seawater intrusion and urbanization expansion. Water quality evaluated by fuzzy comprehensive method showed that 21.05% of samples distributed around reservoirs were classified into grade II or better. Nearly 79% of samples distributed in the densely populated urban land were classified into grade III or worse, indicating pollution from anthropogenic factors cannot be ignored. For the river tidal reach where river stage fluctuated about 0.5 to 1.5 m within a tidal cycle, the chemical composition of groundwater was influenced by frequent water exchange with the river. The carcinogenic and non-carcinogenic health risks for different age groups, from the high to the low, were children, adult women, adult men, adolescent women, and adolescent men, respectively. Approximately 39% of groundwater samples distributed around the densely populations area with health risk larger than 5 × 10-5 were unacceptable for children. This investigation would be helpful for improving groundwater management and as a practical reference for sustainable groundwater exploitation in the MRB.

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There are five different primate species inhabiting widely distinct ecoregions in Argentina. Each of them faces various threats in terms of conservation and conflicts that hamper their ability to coexist with human populations. We present here some of the drivers known to be the causes of conflicts between humans and primates in the southernmost area of distribution of Latin American primates. We focus our synthesis on two of the biggest sources of conflict: the effects of different anthropogenic disturbances, and human misconceptions concerning the role of primates in the ecosystem. In each section, we briefly characterize the conflicts worldwide and then provide specific cases and examples from Argentina. In the last part of the manuscript, we further describe some ongoing national and regional educational, research, and conservation approaches to mitigate those effects.

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Assessing natural background levels (NBLs) in groundwater is a global concern. Knowledge on groundwater NBLs in urbanized areas is challenging due to the impact of complex human activities. Preselection related methods are common ones for assessing groundwater NBLs. The present study used three preselection related methods to assess groundwater heavy metals (lead, zinc, barium) NBLs in four groundwater units of the Pearl River Delta (PRD) where urbanization continues, and to identify the best one for assessing groundwater NBLs in urbanized areas. Here, methods include a preselection method (method-P), a preselection dominated method (method-PD), and a statistic dominated method (method-SD). Results showed that the method-PD was better than other two methods for assessing groundwater NBLs of heavy metals in the PRD. This is supported by the evidence that differences among heavy metals concentrations in various land-use types in residual datasets formed by the method-PD were insignificant. NBLs of lead in groundwater units I to IV assessed by the method-PD were 2.8 µg/L, 5.9 µg/L, 5.8 µg/L, and 2.6 µg/L, respectively. NBLs of zinc in groundwater units I to IV assessed by the method-PD were 30 µg/L, 180 µg/L, 160 µg/L, and 100 µg/L, respectively. NBLs of barium in groundwater units I to IV assessed by the method-PD were 120 µg/L, 120 µg/L, 90 µg/L, and 50 µg/L, respectively. Compared to the method-PD, the method-SD often underestimates groundwater NBLs of heavy metals because of using the experiential evaluation for residual datasets. The method-P also has an inaccurate evaluation of groundwater NBLs of heavy metals in comparison with the method-PD, owing to both of using the experiential evaluation and the absence of a function for outliers test. The method-P combining with an outliers test would be better than itself for assessing groundwater NBLs. Therefore, the method-PD is the first choice to be recommended for assessing groundwater NBLs in urbanized areas such the PRD. However, this method should not be taken into account for assessing groundwater NBLs in areas where groundwater Cl/Br mass ratios are invalid. Instead, the method-SD and the method-P combining with one outliers test may be choices, because no constraint for these two methods.

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In Brazil, scarce air quality data hinders air pollutant chemical understanding and policy decisions regarding public health and environmental impacts. From this perspective, our study assessed the O3, PM2.5, and PM10 yearly and seasonal trends and also the WHO Air Quality Guidelines 2021 exceedance trends at 40 air quality stations located in four highly urbanized zones in Brazil (Belo Horizonte, São Paulo, Rio de Janeiro, and Espírito Santo) from early 1990s up to 2019. We applied the Mann-Kendall test aligned with Sen's Slope estimator to assess the trends and the Cox-Stuart test to verify the WHO AQG 2021 exceedances trends. Our findings pointed out that the current national legislation is outdated when compared to WHO AQG 2021 values, leading to multiple exceedances episodes. We also found out that 62% of São Paulo's stations presented O3 increasing trends, while in Rio de Janeiro 85.7% presented decreasing trends. The Cox-Stuart test pointed out that PM2.5 exceedance trends showcase positive values, and most of the significative values are located in São Paulo stations. Therefore, we endorse that the national legislation needs to be updated meanwhile the air monitoring network needs to expand its coverage.

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Regional integration is a development strategy that synergizes various components as a whole to maximize overall benefits. The natural heterogeneity and fluidity of ecosystem service (ES) make it a promising target for regional integration. However, the current focus on regional integration was more on the socio-economic factors rather than ecological resources, and the understanding of the supply-demand relationship and potential flow of ecosystem services was still limited. Therefore, we attempted to interpret ecological integration management by linking ES budgets, bundles, and flows in this study. The results showed that the spatial mismatches of ESs supply-demand were observed in all six selected ES types. Most of the ESs deficit regions were concentrated in urban centers, while ES surplus regions were scattered in surrounding rural areas. Multiple heterogeneous ES resources could ideally benefit an additional 0.13-4.84 million people in 9-70 townships through potential ES flows under ecological integration management. Therefore, we connected the service provisioning areas (SPAs) and service beneficiary areas (SBAs) with three types of ES flows and drew the potential provider-beneficiary relationship networks at the townships/bundles scale, demonstrating the interactive relationship of ecological integration within the region. On this basis, we also proposed the applicability matrix of governance tools for the first time according to the type of ES flows, and then put forward the corresponding governance opinions around the two aspects of "improving ES budges within clusters" and "strengthening ES flow among clusters". This study provided an ecological perspective for understanding regional integration, and relevant conclusions can inform environmental policy priorities for sustainable decision-making in urbanized areas.

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The estuaries of Maharashtra are under continuous pressure due to uncontrolled dumping of persistent toxic organic pollutants into these regions and their impact on the marine environment. In this study, total petroleum hydrocarbons (TPHs) in water, sediments, fish, and biomarker responses in the Coilia dussumieri exposed to TPHs were determined in seven urbanized tropical estuaries along the west coast of India during the winter and summer. The results of the cluster analysis highlighted that the concentration of TPHs in the water, sediment, and fish in the study area was spatially varied, with the highest concentration in the northern area of Maharashtra (NM) estuaries than in the southern region of Maharashtra (SM) estuaries during both seasons. The enrichment of TPHs in water and sediment in the middle part of most estuaries highlights the addition of anthropogenic organic matter. A higher concentration of TPHs in the muscle tissue of Coilia dussumieri observed in NM during the winter season, indicates the energetic intake and storage of large quantities of TPHs in their muscle tissue. The biochemical results showed decreased levels of total protein (PRT) under exposure to TPHs, under oxidative stress and reversing correlations was observed between catalase (CAT) and lipid peroxidation (LPO) activities with the respective TPHs. Similarly, reduced activity of the CAT antioxidant and increased glutathione-S-transferase (GST) under exposure to TPHs were more likely to occur under hydrocarbon stress. However, current results indicate that Coilia dussumieri actively produces oxidative stress and antioxidant reaction that can be used as biomarkers of pollution in the study area.

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As major carriers of modern economy and population, cities and towns are vortex centers of pollution migration, and the environmental effects brought about by China's unprecedented urbanization can be imagined, although the specific scale is still a mystery. This paper focuses on the nonlinear response mechanism of urban PM2.5 concentration to the urbanization population scale, considering that China's urbanization development path is dominated by large- and medium-sized cities. The panel data of PM2.5 concentration of Chinese cities observed by satellite during 1998-2016 are used to capture the nonlinear characteristics of panel threshold model (PTM). The estimation results of the double-threshold PTM including the quadratic term of urbanization population show that the U-shaped relationship between urbanization population and PM2.5 concentration is nonlinear adjusted by urban GDP per capita with the two thresholds of 6777 Yuan and 10,296 Yuan at 2010 constant price. When the urban GDP per capita exceeds 10,296 Yuan, the urbanized population at the turning point of the U-shaped curve is 12.967 million people, which only appears in a few super-large cities such as Beijing, Tianjin, Shanghai and Chongqing. The size matching of urban economy and population is an important follow-up of environmental policies.

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Public health risks are related to environmental management practices, and are essential to the understanding of ecosystem dynamics. The expansion of urbanized areas affects migratory bird networks and can impact the population sizes of migratory species and, in parallel, increase the risk of diseases carried by migratory species spreading into urban areas. Taking the European population of the common quail as a case study, we reconstructed its migratory network between Europe and the Maghreb using quail recoveries from the Italian Bird Ringing Scheme. We showed that soils at the central European migratory node have been degraded through urbanization and reforestation, decreasing the number of successful migrations over this area. Conceptual models incorporating the One Health approach, natural and social capital, landscape infrastructure, and ecosystem services could explain the relationships between climate warming and extensively developed, intensively developed, and urbanized ecosystems. Failed migratory flights of quail over central Europe highlight not only the problems of infrastructure design and their impact on ecosystems services, but also on One Health parameters. The damage to migratory network nodes presents a global threat to biodiversity and can increase the spread of diseases. To address this challenge we propose: i) improvements in land quality; ii) transboundary migration monitoring programmes; and iii) management plans for migratory birds - the overall aim being to optimize infrastructures to improve the quality of human life. Lessons drawn from a better understanding of the migratory networks of quail in relation to different ecosystems provide useful tools to improve infrastructure management and political decision making processes.

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The leaching risk of heavy metals in soil has a large spatial variability on a regional scale. Taking the Chang-Zhu-Tan area as the research object, this work studied the distribution and influencing factors of available contents and solid-solution partition coefficient (Kd) of Cd and Pb in soil with land uses and clarified the environmental risk of heavy metals in soil based on Kd values measured by CaCl2 (soil-to-water ratio, 1:0.5). The results showed that the contents of available Cd and Pb in soil followed the order of forest land>suburban farmland>urban green space>industrial green space. The average Kd of Cd in soil was 449.79 L·kg-1, and that of Pb was 27604.07 L·kg-1, indicating that the mobility of Cd in the soil was significantly higher than that of Pb. The Kd values of forest soil were significantly lower than that in the other land uses. The Kd values were mainly affected by soil pH and the total content of heavy metals in soil. Adopting the available content of heavy metals measured by CaCl2 (soil-to-water ratio, 1:10) as a dependent variable, the multiple regressions effectively predicted the Kd values of Cd and Pb in soil, with R2 values of 84.2% and 67.6%, respectively. The environmental risk assessment indicated that the leaching risk in 93.8%-96.1% of the sampling sites could be ignored, whereas a few sampling sites near factories with low pH may pose a risk to the groundwater environment. The mobility of heavy metals in soil and the distribution of pollution sources determined the leaching risk of heavy metals. The results provide a method and theoretical support for preventing the environmental risk of heavy metals in soil on a regional scale.

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Water transfer is an effective measure to enhance hydrodynamic and water quality in highly urbanized areas. The effect of water transfer in highly urbanized areas is affected by strong artificial interventions, and it is difficult to evaluate the improvement of multiple indicators of many sections after water transfer. At present, there is no analysis framework directly evaluates the improvement of water environment under strong artificial interventions, making it difficult to determine the optimal scheduling of hydraulic projects. This study constructed a multi-criteria analysis framework for evaluating the improvement of water environment including index layers of water quality improvement, hydrodynamic improvement and economic cost, and designed corresponding element layers for each index layer. The weights of each element were determined based on fuzzy analytical hierarchy process, and the fuzzy comprehensive evaluation method was used for comprehensive evaluation. The framework was applied in Xishan District in highly urbanized Taihu Lake Basin, and the results showed that the proposed framework could effectively determine the optimal scheduling of hydraulic projects. Water quality compliance rate for the optimal water transfer scheme achieved in Xishan District was 82%, average rate of water quality improvement was 31%, and proportion of cross-sections meeting the Class III water quality standard was 61%. Average flow velocity was 0.10 m/s, proportion of the optimal velocity was 39%, and proportion of stagnant sections was 32%. Furthermore, the impact of regional control projects on the effect of water transfer was much greater than local projects, consequently, the best scheduling mode for regional control projects should be first determined, and then the scheduling combination for local projects. This study can provide a new framework for the assessment of water transfers to improve the water environments and a scientific basis for the dispatching of hydraulic projects in Taihu Lake Basin.

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The effect of heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) pollution on the microbiological status of soils on the coast of the Taganrog Bay and adjacent areas was studied. The content of total and exchangeable forms of HMs, the content of 16 priority PAHs and the abundance of several groups of culturable microorganisms was determined, namely copiotrophic, prototrophic, aerobic spore-forming bacteria, actinomycetes, molds and yeasts. The content of total and exchangeable forms of HMs in urban coastal soils in industrial zone significantly exceeded that in non-urban soils. The maximum concentrations of total forms of Mn, Cr, Ni, Cu, Zn, Pb and Cd are 1821, 871, 143, 89, 1390, 317 and 10 mg/kg, respectively. The median value of the total content of 16 PAHs in urban soils is 3 times higher than in the soils of natural areas and reached 4309 ng/g. The lowest numbers of copiotrophic bacteria, prototrophic bacteria and aerobic spore-forming bacteria were found in the soils of industrial zone: 6.8, 13.8 and 0.63 million CFU g-1 dry soil, respectively. The largest numbers of copiotrophic bacteria, prototrophic bacteria and aerobic spore-forming bacteria were recorded in the soils of natural areas-72.5, 136 and 5.73 million CFU g-1 dry soil, respectively. It was found that the abundance of copiotrophs, prototrophs, and aerobic spore-forming bacteria is more affected by the urbanization of coastal soils including the pollution of HMs and PAHs. Other groups of microorganisms (actinomycetes, molds and yeasts) turned out to be more resistant to anthropogenic factors.

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We investigated the sediment carbon (C) stocks, sequestration and sources in tidal flats and their adjacent mangroves in two coastal wetlands in Hong Kong (the Mai Po Nature Reserve (MPNR) and Ting Kok (TK)), part of a megacity of ∼20 million. At both locations, the C stock of tidal flats was lower than that of mangroves. In MPNR, tidal flats indicated a higher C burial rate (75.2 g C m-2 yr-1) compared to mangroves (64.3 g C m-2 yr-1). The C of tidal flats mainly originated from mangroves and riverine sources, while those in deeper sediments (below 60 cm) in the mangroves originated from the tidal flats. In TK, the C of tidal flats was dominated by oceanic sources. Our study indicates that tidal flats are also important in coastal C sequestration. On highly urbanized coasts, tidal flats and their connected mangroves can play a critical role for C mitigation.

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Although urbanization has been widely examined in individual city and urban agglomeration scales, urban expansion patterns and dynamics in large-scale agricultural districts remain absent. In this study, multifaceted characteristics in urban expansion were quantified in China's nine national-level agricultural districts, and responses of dry-wet circumstances to urban sprawl were evaluated. From 1980 to 2018, China has undergone an extensive urban sprawl. Huang-Huai-Hai Plain (HHHP) has the maximum urban coverage extent, followed by Middle-lower Yangtze Plain (MLYP) and Southern China (SC). The largest annual increase was recorded in MLYP, reaching 816.12 km2; followed by HHHP, with an annual increase of 725.22 km2. There are prominent heterogeneities in expansion rate and direction among various districts. The dominating growth patterns were edge- and leapfrogging-expansion, accompanying by a less percentage of infilling-expansion. Accompanying by urbanization, connectedness in urban landscapes gradually improved, while separation degree decreased. Upon many occasions, holistic average dry-wet circumstances in non-urbanized areas are superior to those in urban areas, although this is not absolute for all the districts or periods. In urbanization progress, the development of leapfrogging-expansion has a potential to ameliorate dry-wet circumstances in both urban and non-urban zones, while infilling- and edge-expansion would constitute an inverse effect. In comparison to urban zones, leapfrogging-expansion would cause a more prominent effect on dry-wet environment in non-urbanized zones. Increased connectivity in urbanized landscapes would improve dry-wet environments, especially for urbanized zones. Inversely, increased spatial separated extent among urban landscapes would perform an opposite effect. This study provides a potential for understanding the dynamic features of urban expansion in large-scale agricultural districts. Moreover, the results can also provide a potential opportunity for optimizing dry-wet environments by regulating urbanization pattern and landscape configuration.

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Urban areas are greatly affected by human activities that may result in the release of microplastics. Fugitive release of microplastics is the unorganized discharge of microplastics produced during plastic manufacturing and use. The microplastics enter the environment in a variety of ways. To investigate fugitively released microplastics and identify the major influencing factors in urban watersheds, the central area of Suzhou city was selected as a case study. This area has a dense network of canals without sources of organized release. The results show that the microplastic abundance in the urban canal of the area ranged from 8.29 to 40.63 particles L-1, with a mean of 14.75 ± 3.95 particles L-1. To better understand the relationship between microplastics and human activities, the main influencing factors, including water quality, water-related activities, dwelling type, urban landscaping, trash collection and land use type, were assessed. Water quality was not correlated with microplastic distribution in the urban watershed, as it is in larger watersheds. Water-related activities caused elevated fugitive release of microplastics. The abundance of microplastics discharged into the water environment in modern communities was significantly less than that discharged in an area of traditional residences. Traffic activities contributed to microplastic release, while urban landscaping physically blocked microplastics from flowing into urban waterbodies to some extent. Trash collection did not reduce the abundance of microplastic particles in the water, despite its ability to remove other types of plastic waste. The results also suggest that the contributions of different land use types to the abundance of microplastics in urban areas from highest to lowest were as follows: tourist districts > commercial areas > public areas > residential areas > roads. Moreover, fugitive release is an important source to be considered in future research on urban microplastic management. The renewal of urban construction to mitigate the influence of human activities on water ecology may play a positive role in controlling the fugitive release of microplastics.

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The urban heat island (UHI) effect is the main problem regarding a city's climate. It is the main adverse effect of urbanization and negatively affects human thermal comfort levels as defined by physiological equivalent temperature (PET) in the urban environment. Blue and green infrastructure (BGI) solutions may mitigate the UHI effect. First, however, it is necessary to understand the problem from the degrading side. The subject of this review is to identify the most essential geometrical, morphological, and topographical parameters of the urbanized environment (UE) and to understand the synergistic relationships between city and nature. A four-stage normative procedure was used, appropriate for systematic reviews of the UHI. First, one climate zone (temperate climate zone C) was limited to unify the design guidelines. As a result of delimitation, 313 scientific articles were obtained (546 rejected). Second, the canonical correlation analysis (CCA) was performed for the obtained data. Finally, our research showed the parameters of the UE facilities, which are necessary to mitigate the UHI effect. Those are building density and urban surface albedo for neighborhood cluster (NH), and distance from the city center, aspect ratio, ground surface albedo, and street orientation for street canyon (SC), as well as building height, material albedo, and building orientation for the building structure (BU). The developed guidelines can form the basis for microclimate design in a temperate climate. The data obtained from the statistical analysis will be used to create the blue-green infrastructure (BGI) dynamic modeling algorithm, which is the main focus of the future series of articles.

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