Pearl River Research Articles

The impact of collaborative agglomeration of manufacturing and services on carbon emission efficiency: spatial effect and mechanism analysis

ABSTRACT Urban economic development benefits from industrial agglomeration by enhancing efficiency, but it may also bring negative effects, such as environmental pollution. This research uses data from 283 Chinese cities from 2007 to 2019, and applies the Spatial Durbin Model to investigate the spatial effects of industrial agglomeration on carbon emission efficiency, along with its impact mechanisms at various stages of collaborative agglomeration between the manufacturing and service sectors. The results indicate that: (1) The upgrading of the service industry from consumption-oriented to production-oriented has proved to be conducive to enhancing carbon emission efficiency and alleviating the environmental problems associated with manufacturing agglomeration. (2) The industrial collaborative agglomeration exerts a spatial spillover effect on carbon emission efficiency. Over time, as the degree of industrial collaborative agglomeration reaches a specific threshold, it positively impacts the carbon emission efficiency within the local area but exerts an inhibitory effect in neighboring regions. (3) The urban agglomerations of Yangtze River Delta, Beijing-Tianjin-Hebei, and Pearl River Delta regions, along with low-carbon pilot cities, demonstrate a greater capacity to enhance the positive impact of industrial collaborative agglomeration on carbon emission efficiency. (4) Collaborative industrial clustering fosters technological progress through domestic technology transfer and green technology innovation. It also mitigates mismatches between labor and capital, enhances land-intensive utilization efficiency, and optimizes resource allocation, ultimately leading to improve carbon emission efficiency. This research contributes to China’s economic and social transition towards a low-carbon future and provides valuable insights for the green development and industrial upgrading of developing countries.

Explaining the changes in the green technology innovation efficiency of construction enterprises

Based on the objective of global carbon emission reduction, the green technology innovation efficiencies of construction enterprises (GTIE–CE) have attracted attention in various countries and regions worldwide. However, researchers have not yet assessed GTIE–CE from the perspectives of asymmetric innovation theory, resource orchestration theory and eco-innovation theory. To reveal the changes in GTIE–CE, an index system is constructed to measure this efficiency based on resource orchestration theory and eco-innovation theory. In addition, based on the asymmetric innovation theory, this study uses the spatial variance function and PVAR model to reveal the evolution mechanism of GTIE–CE with respect to market, government and technology dimensions. The main conclusions are as follows. (1) Regional heterogeneity is present in GTIE–CE in China, and the appearance of high efficiency spreads from the Yangtze River Delta and Pearl River Delta to the surrounding areas. (2) The market dimension positively affects the green technology innovation efficiency of construction enterprises, but this effect is delayed. (3) The government dimension significantly promotes the improvement in GTIE–CE, but this effect is delayed. This study provides an integrated theoretical perspective that reveals the mechanism of GTIE–CE, helps to broaden the research in the field of GTIE–CE, in addition to insights from China to further promote the green transformation of these enterprises.

Labile organic matter favors a low N2O yield during nitrogen removal in estuarine sediments

Estuary harbors the active sediment denitrification and nitrous oxide (N2O) emission, while the knowledge of environmental controls on the denitrification-derived N2O yield remains underexplored. Here, we quantitatively assess the potential and in situ rates of N2O production during sediment denitrification in the Pearl River Estuary (PRE), China. Organic matter determines the product stoichiometry and capacity of nitrogen removal. In particular, labile organic matter (LOM) reduces N2O yield via enhancing the complete coupled nitrification-denitrification. Our results reveal that the chain processes, primary production-LOM settling-sedimentary respiration-coupled nitrification-denitrification, control the sediment denitrification and N2O production, linking the carbon and nitrogen biogeochemical cycles in the atmosphere-water column-sediment continuum. The PRE sediments serve as nitrogen removal hotspots but with low efficiency (~25 % of riverine input) and strong N2O release (~66 % of daily sea-air N2O efflux). These findings contribute to policy makers to develop knowledge-based management actions for achieving sustainable coastal environments and mitigating N2O emission.

A Novel Interpolation Method for Soil Parameters Combining RBF Neural Network and IDW in the Pearl River Delta

Soil fertility is a critical factor in agricultural production, directly impacting crop growth, yield, and quality. To achieve precise agricultural management, accurate spatial interpolation of soil parameters is essential. This study developed a new interpolation prediction framework that combines Radial Basis Function (RBF) neural networks with Inverse Distance Weighting (IDW), termed the IDW-RBFNN. This framework initially uses the IDW method to apply preliminary weights based on distance to the data points, which are then used as input for the RBF neural network to form a training dataset. Subsequently, the RBF neural network further trains on these data to refine the interpolation results, achieving more precise spatial data interpolation. We compared the interpolation prediction accuracy of the IDW-RBFNN framework with ordinary Kriging (OK) and RBF methods under three different parameter settings. Ultimately, the IDW-RBFNN demonstrated lower error rates in terms of RMSE and MRE compared to direct RBF interpolation methods when adjusting settings based on different power values, even with a fixed number of data samples. As the sample size decreases, the interpolation accuracy of OK and RBF methods is significantly affected, while the error of IDW-RBFNN remains relatively low. Considering both interpolation accuracy and resource limitations, we recommend using the IDW-RBFNN method (p = 2) with at least 60 samples as the minimum sampling density to ensure high interpolation accuracy under resource constraints. Our method overcomes limitations of existing approaches that use fixed steady-state distance decay parameters, providing an effective tool for soil fertility monitoring in delta regions.

Impacts of tropical cyclone–heat wave compound events on surface ozone in eastern China: comparison between the Yangtze River and Pearl River deltas

Abstract. China has implemented some air pollution management measures in recent years, yet severe ozone pollution remains a significant issue. The southeastern coast of China (SECC) is often influenced by hot extremes and tropical cyclones (TCs), and the two can occur simultaneously (TC–HDs). The compound TC–HDs show a rising trend in the summers of 2014–2019, potentially affecting ozone pollution. Here, we found that surface ozone concentrations over the SECC are more elevated during extremely hot days than the summer climatology. However, compared to extremely hot days alone (AHDs), the maximum 8 h average ozone (MDA8 O3) concentration increases by an average of 6.8 µg m−3 in the Pearl River Delta (PRD) and decreases by 13.2 µg m−3 in the Yangtze River Delta (YRD) during the compound TC–HDs. The meteorological conditions during AHDs favor the chemical production of ozone over the SECC, exhibiting increased temperature and solar radiation and decreased relative humidity. Relative to AHDs, strong northeasterly winds prevail in the SECC during TC–HDs, suggesting the potential of ozone cross-regional transport between YRD and PRD. The process analysis in the chemical transport model (GEOS-Chem) suggests that relative to AHDs, the chemical production of ozone is enhanced in YRD during TC–HDs, while horizontal transport alleviates ozone pollution in YRD but worsens it in PRD through cross-regional transport. The results highlight the significant effects of cross-regional transport in modulating ozone pollution in the two megacity clusters during hot extremes accompanied by TC activities, giving insight into future ozone control measures over the SECC under global warming.

Metagenomic analysis manifesting intrinsic relatedness between antibiotic resistance genes and sulfate- and iron-reducing microbes in sediment cores of the Pearl River Estuary

Antibiotic resistance is an increasingly concerned hotspot of human health. Microbial determinants that may affect the profiles of antibiotic resistance genes (ARGs) in the environments need be explored. Here, sediment cores in the Pearl River Estuary (PRE) were analyzed using metagenomic approaches. ARGs were vertically stratified in the PRE sediment cores in terms of both diversity and absolute levels. Multidrug resistance genes could account for approximately 65.0% of the total ARGs, followed by sulfonamides (19.1%), aminoglycosides (5.9%), beta-lactams (4.5%), etc. ARGs related to aminoglycosides, lincosamides, macrolides, sulfonamides and tetracyclines were preferentially enriched in the surface layers of sediment cores. Sulfate-reducing microbes (SRMs) (e.g., Desulfocapsa and Desulfobulbus) and iron-reducing microbes (IRMs) (e.g., Pseudomonas and Sulfurospirillum) were consistently popular and dominant in the PRE sediment cores. The total levels of both SRMs and IRMs were significantly correlated with those of ARGs in the PRE sediment cores (p < 0.01). Network analysis showed that SRM and IRM genera (i.e., Pseudomonas, Shewanella, and Desulfovibrio) had the high co-occurrence with multiple ARG subtypes in the PRE sediment cores such as rsmA, mexK, and mexF. This study highlighted that anaerobic microbes could play significant roles in shaping vertical ARG distribution in the sediments of aquatic environments.

A Study on the Mechanical Behaviour of Pearl River Estuary Sediments

A Study on the Mechanical Behaviour of Pearl River Estuary Sediments

Measurement and Analysis of Carbon Emission Efficiency in the Three Urban Agglomerations of China

China aims to reduce its carbon emissions to achieve carbon peaking and neutrality. Measuring the carbon emission efficiency of three urban agglomerations in China, exploring their spatiotemporal characteristics, and investigating the main influencing factors are crucial for achieving regional sustainable development and dual carbon goals. Using the super-slack-based measurement (super-SBM) model, we calculated the carbon emission efficiency of the Beijing–Tianjin–Hebei (BTH), Yangtze River Delta (YRD), and Pearl River Delta (PRD) urban agglomerations from 2011 to 2021 and explored the spatiotemporal non-equilibrium characteristics of carbon emission efficiency and its influencing factors. The results indicated that: (1) Overall, the carbon emission efficiency showed an N-type trend, with the PRD having the highest average efficiency. Regional differences between the YRD and BTH regions gradually increased. (2) The efficiency hotspots shifted from the PRD to the YRD, whereas the cold spots were mainly concentrated in the BTH region. The variation in the standard deviation ellipse radius of carbon emission efficiency in the urban agglomerations was clear, and the spatial disequilibrium was significant. (3) Economic level and opening up had positive impacts on carbon emission efficiency, whereas energy intensity and industrial structure had negative impacts. The effects of population size, government intervention, and technological level varied among the regions.

Similarities and differences in bacterial communities between the Pearl River (Guangzhou section) and its estuary.

The Pearl River and its estuary are highly exposed to anthropogenic disturbance. Because bacterial communities play an indispensable role in aquatic ecosystems, there has been an increased research focus on the statuses of these communities under human-induced perturbations. This study investigated the composition, diversity, and structure of bacterial communities across 29 sites from the Guangzhou section of the Pearl River (GZ) to the Pearl River Estuary (PRE) using 16S rRNA gene amplicons. The results revealed similar dominant phyla of bacteria in both GZ and PRE, as well as significant differences in bacterial community composition and diversity between the two sections. Proteobacteria and Cyanobacteria were identified as the primary drivers of compositional differences between GZ and PRE. The Cyanobacteria Dolichospermum_NIES41 and Cuspidothrix issatschenkoi were only present in GZ, whereas the marine Gram-negative bacteria of Porticoccus litoralis and Thalassolituus oleivorans were unique to PRE. Bacterial community composition and diversity exhibit both similarities and differences between GZ and PRE; Proteobacteria and Cyanobacteria are key factors underlying these variations. Bacterial communities in both GZ and PRE are strongly influenced by human activities, and salinity is an important factor in controlling their differences. This study provides a comprehensive analysis of the bacterial communities in GZ and PRE, establishing a foundation for better management of aquatic ecosystems impacted by anthropogenic activities.

ACEIC: a comprehensive anthropogenic chlorine emission inventory for China

Abstract. Chlorine species play a crucial role as precursors to Cl radicals, which can significantly impact the atmospheric oxidation capacity and influence the levels of trace gases related to climate and air quality. Several studies have established a chlorine emission inventory in China in recent years, but the emission remains uncertain and requires further investigation. The Anthropogenic Chlorine Emission Inventory for China (ACEIC) was the first chlorine emission inventory for China based on local data developed in our previous study, which only includes the emissions from coal combustion and waste incineration. In this study, we updated this inventory to include data for a more recent year (2019) and expanded the range of species considered (HCl, fine particulate Cl−, Cl2, and hypochlorous acid (HOCl)) and the number of anthropogenic sources (41 specific sources). Compared with previous studies, this updated inventory considered more anthropogenic sources, used more localized emission factors, and adopted more refined estimation methods. The total emissions of HCl, fine particulate Cl−, Cl2, and HOCl in mainland China for the year 2019 were estimated to be 361 (−18 % to 27 %), 174 (−27 % to 59 %), 18 (−10 % to 15 %), and 79 (−12 % to 18 %) Gg, respectively. To facilitate analysis, we aggregated the chlorine emissions from various sources into five economic sectors: power, industry, residential, agriculture, and biomass burning. HCl emissions were primarily derived from the industry (43 %), biomass burning (38 %), and residential (13 %) sectors. The biomass burning and industry sectors accounted for 74 % and 19 % of the fine particulate Cl− emissions, respectively. Residential and industry sectors contributed 61 % and 29 % of the total Cl2 emissions. HOCl emissions were predominantly from the residential sector, constituting 90 % of the total emissions. Notably, the usage of chlorine-containing disinfectants was identified as the most significant source of Cl2 and HOCl emissions in the residential sector. Geographically, regions with high HCl and fine particulate Cl− emissions were found in the North China Plain, northeastern China, central China, and the Yangtze River Delta, whereas the Pearl River Delta, Yangtze River Delta, and Beijing–Tianjin–Hebei regions exhibited elevated levels of Cl2 and HOCl emissions. Regarding monthly variation, emissions of HCl and fine particulate Cl− were higher during early spring (February to April) and winter (December to January) due to intensified agricultural activities, while Cl2 and HOCl emissions were higher in the summer months due to increased demand for water disinfection. We incorporated this emission inventory into the chemical transport model and found the simulated concentrations of chlorine species agreed reasonably well with the observations, which suggested the relatively faithful estimations of their emissions. This updated inventory contributes to a better understanding of anthropogenic sources of chlorine species and can aid in the formulation of emission control strategies to mitigate secondary pollution in China.

Carbonyl Compounds Observed at a Suburban Site during an Unusual Wintertime Ozone Pollution Event in Guangzhou

Carbonyl compounds are important oxygenated volatile organic compounds (VOCs) that play significant roles in the formation of ozone (O3) and atmospheric chemistry. This study presents comprehensive field observations of carbonyl compounds during an unusual wintertime ozone pollution event at a suburban site in Guangzhou, South China, from 19 to 28 December 2020. The aim was to investigate the characteristics and sources of carbonyls, as well as their contributions to O3 formation. Formaldehyde, acetone, and acetaldehyde were the most abundant carbonyls detected, with average concentrations of 7.11 ± 1.80, 5.21 ± 1.13, and 3.00 ± 0.94 ppbv, respectively, on pollution days, significantly higher than those of 2.57 ± 1.12, 2.73 ± 0.88, and 1.10 ± 0.48 ppbv, respectively, on nonpollution days. The Frame for 0-D Atmospheric Modeling (F0AM) box model simulations revealed that local production accounted for 62–88% of observed O3 concentrations during the pollution days. The calculated ozone formation potentials (OFPs) for various precursors (carbonyls and VOCs) indicated that carbonyl compounds contributed 32.87% of the total OFPs on nonpollution days and 36.71% on pollution days, respectively. Formaldehyde, acetaldehyde, and methylglyoxal were identified as the most reactive carbonyls, and formaldehyde ranked top in OFPs, and it alone contributed 15.92% of total OFPs on nonpollution days and 18.10% of total OFPs on pollution days, respectively. The calculation of relative incremental reactivity (RIR) indicates that ozone sensitivity was a VOC-limited regime, and carbonyls showed greater RIRs than other groups of VOCs. The model simulation showed that secondary formation has a significant impact on formaldehyde production, which is primarily controlled by alkenes and biogenic VOCs. The characteristic ratios and backward trajectory analysis also indicated the indispensable impacts of local primary sources (like industrial emissions and vehicle emissions) and regional sources (like biomass burning) through transportation. This study highlights the important roles of carbonyls, particularly formaldehyde, in forming ozone pollution in megacities like the Pearl River Delta region.

The Single-Scattering Albedo of Black Carbon Aerosols in China

Black carbon (BC) aerosols have attracted wide attention over the world due to their significant climate effects on local and global scales. BC extinction aerosol optical thickness (AOT), scattering AOT, and single scattering albedo (SSA) over China are systematically studied based on the MERRA-2 satellite reanalysis data from 1983 to 2022 in terms of the spatial, yearly, seasonal, and monthly variations. The extinction and scattering AOTs of BC show similar spatial distribution, with high values in eastern and southern China, generally as opposed to BC SSA. A decrease in BC extinction and scattering AOTs has been documented over the last decade. The mean BC extinction AOT, scattering AOT, and SSA over China are 0.0054, 0.0014, and 0.26, respectively. The BC SSA showed small variations during 1983–2022, although a high BC extinction AOT and scattering AOT have been seen in the last two decades. During different decades, the seasonal patterns of BC extinction and scattering AOTs may differ, whereas the BC SSA shows seasonal consistency. Significant monthly variations in the BC SSA are seen over four decades, which are in agreement with their seasonal patterns. The mean BC extinction AOTs are 0.037, 0.033, 0.023, and 0.0054, whereas the average BC scattering AOTs are 0.0088, 0.0082, 0.0060, and 0.0014 in the Pearl River Delta (PRD), Yangtze River Delta (YRD), Beijing–Tianjin–Hebei (BTH) region, and Tarim Basin (TB), respectively. It is interesting to see that BC SSA values in the TB region are generally higher than those over the PRD, YRD and BTH areas, whereas the reverse is true for BC extinction and scattering AOTs. This study provides references for further research on black carbon aerosols and air pollution in China.

Distribution and Controlling Factors of the Contourites on the Northern Continental Slope of the South China Sea

ABSTRACTThe northern continental margin of the South China Sea (SCS) is an important component of deep‐water circulation, providing excellent conditions for studying bottom currents in a marginal sea. Seismic data were employed to discern the sedimentary patterns prevalent in the deep‐water continental slope sediments on the northern continental margin of the SCS, encompassing gravity flow, contourite and mixed depositional systems. The contourite depositional system includes various types of deposits (such as separated mounded drifts, patch or channel‐related drifts, deformed sheeted drifts, composite drifts, bottom current sediment waves, plastered contourite drifts) and various morphologic erosional features eroded by the bottom current (such as moats, non‐depositional surfaces, troughs and scarps). These contourite features are related to the continental slope's morphology and its sources. The Dongsha slope exhibits distinctive characteristics marked by intense bottom current erosion and deposition, featuring separated mounded drifts and deformed sheeted drifts along its lower slope. The lower slope of the Pearl River showcases a spectrum of bottom current‐induced features, including sediment wave fields, erosion fields and contourite drifts. The southern flank of the Shenhu slope is characterised by a bottom current erosion field, a non‐depositional surface, a sediment wave field and isolated mounded drifts. On the Yingqiong slope, the contourite drifts are limited to its southern flank where gravity flow action is absent, and the complex geomorphology interacts with the bottom current, forming a complex contourite depositional system. The results of this study serve as a foundational framework for further global research on bottom current circulation and hydrodynamics.

Decoding Adverse Effects of Organic Contaminants in the Aquatic Environment: A Meta-analysis of Species Sensitivity, Hazard Prediction, and Ecological Risk Assessment.

Aquatic organisms in the environment are frequently exposed to a variety of organic chemicals, while these biological species may show different sensitivities to different chemical groups present in the environment. This study evaluated species sensitivity, hazards, and risks of six classes of organic chemicals in the aquatic environment. None of the taxonomic groups were the most sensitive or tolerant to all chemicals, as one group sensitive to one class of chemicals might possess adaptations to other chemical groups. Polychlorinated biphenyls were generally the most toxic chemical group, followed by polybrominated diphenyl ethers, polycyclic aromatic hydrocarbons, and pharmaceuticals and personal care products, while per- and polyfluoroalkyl substances and phthalate esters were the less toxic chemical groups. The hazard of organic chemicals was closely related to their physicochemical properties, including hydrophobicity and molecular weight. It was shown that 20% of the evaluated chemicals exhibited medium or high ecological risks with the worst-case scenario in the Pearl River Estuary. This novel work represented a comprehensive comparison of chemical hazards and species sensitivity among different classes of organic chemicals, and the reported results herein have provided scientific evidence for ecological risk assessment and water quality management to protect aquatic ecosystems against organic chemicals.

Spatiotemporal Evolution and Influencing Factors of Coupling and Coordination between the Ecosystem Service Value and Economy in the Pearl River Delta Urban Agglomeration of China

In the context of pursuing high-quality development, the coupling and coordination of the ecosystem and economy has become the fundamental goal and inevitable choice for achieving the sustainable development of urban agglomerations. Based on remote sensing and statistical data for the Pearl River Delta (PRD) region from 2005 to 2020, in this paper, we construct an index system of the ecological and economic levels to assess the ecosystem service value (ESV). We use the equivalent factor method, entropy method, coupling coordination model, and relative development model to systematically grasp the spatial pattern of the levels of the two variables, analyse and evaluate their spatial and temporal coupling and coordination characteristics, and test the factors influencing their coupling and coordination using the geographical and temporal weighted regression (GTWR) model. The results show that ① the ESV in the PRD exhibited a fluctuating decreasing trend, while the level of the economy exhibited a fluctuating increasing trend; ② the coordination degree of the ESV and economy in the PRD exhibited a fluctuating increasing trend, and the region began to enter the basic coordination period in 2007; ③ in terms of the spatial distribution of the coordination degree, there was generally a circular pattern, with the Pearl River Estuary cities as the core and a decrease in the value towards the periphery; ④ the coordinated development model is divided into balanced development, economic guidance, and ESV guidance, among which balanced development is the major type; ⑤ the results of the GTWR reveal that the influencing factors exhibited significant spatial–temporal heterogeneity. Government intervention and openness were the dominant factors affecting the coordination, and the normalised difference vegetation index was the main negative influencing factor.

Analysis of Spatiotemporal Predictions and Drivers of Carbon Storage in the Pearl River Delta Urban Agglomeration via the PLUS-InVEST-GeoDetector Model

Land use and land cover change (LUCC) significantly influences the dynamics of carbon storage in thin terrestrial ecosystems. Investigating the interplay between land use alterations and carbon sequestration is crucial for refining regional land use configurations, sustaining the regional carbon balance, and augmenting regional carbon storage. Using land use data from the Pearl River Delta Urban Agglomeration (PRDUA) from 2010 to 2020, this study employed PLUS-InVEST models to analyze the spatiotemporal dynamics of land use and carbon storage. Projections for the years 2030, 2040, and 2050 were performed under three distinct developmental scenarios, namely, natural development (ND), city priority development (CPD), and ecological protection development (EPD), to forecast changes in land use and carbon storage. The geographic detector model was leveraged to dissect the determinants of the spatial and temporal variability of carbon storage, offering pertinent recommendations. The results showed that (1) during 2010–2020, the carbon storage in the PRDUA showed a decreasing trend, with a total decrease of 9.52 × 106 Mg, and the spatial distribution of carbon density in the urban agglomeration was imbalanced and showed an overall trend in increasing from the center to the periphery. (2) Clear differences in carbon storage were observed among the three development scenarios of the PRDUA between 2030 and 2050. Only the EPD scenario achieved an increase in carbon storage of 1.10 × 106 Mg, and it was the scenario with the greatest potential for carbon sequestration. (3) Among the drivers of the evolution of spatial land use patterns, population, the normalized difference vegetation index (NDVI), and distance to the railway had the greatest influence on LUCC. (4) The annual average temperature, annual average rainfall, and GDP exerted a significant influence on the spatiotemporal dynamics of carbon storage in the PRDUA, and the interactions between the 15 drivers and changes in carbon storage predominantly manifested as nonlinear and double-factor enhancements. The results provide a theoretical basis for future spatial planning and achieving carbon neutrality in the PRDUA.

Analysis on Ecological Network Pattern Changes in the Pearl River Delta Forest Urban Agglomeration from 2000 to 2020

The advancement of urbanization has led to a decline in the ecological function and environmental quality of cities, seriously reducing the services and sustainable development capacity of urban ecosystems. The construction of the National Forest Urban Agglomeration of China is conducive to alleviating the ecological and environmental problems brought about by rapid urbanization and promoting sustainable urban development. A time series analysis of ecological network changes can quickly and effectively explore the development and changes of ecological spatial patterns over time. Identifying ecological protection and restoration areas in urban agglomerations is an important way to promote ecosystem restoration and optimize ecological networks. This paper takes the Pearl River Delta forest urban agglomeration as the research area, uses multi-source remote sensing data from 2000 to 2020 (every 5 years), identifies ecological sources based on the morphological spatial pattern analysis (MSPA) method, generates ecological corridors based on the minimum cumulative resistance (MCR) model, constructs a time series ecological network pattern in the Pearl River Delta region, and analyzes the evolution process of the ecological network pattern over time. The results indicate that over time, the core green area in the ecological network pattern of the Pearl River Delta first decreased and then increased, and the complexity of ecological corridors first decreased and then increased. The main reason is that the urbanization process in the early 21st century led to severe ecological fragmentation. Under the promotion of the national forest urban agglomeration construction, the ecological network pattern of the Pearl River Delta was restored in 2015 and 2020. The time series analysis of the ecological network pattern in the Pearl River Delta region of this research confirms the effectiveness of the construction of forest urban agglomerations, providing a scientific reference for the identification of ecological networks and optimization of spatial patterns in forest urban agglomerations.

Establishment of the first dermal fibroblast cell line derived from the Indo-Pacific Bottlenose Dolphin (Tursiops aduncus) and its response to pollutant exposure

The Indo-Pacific bottlenose dolphin (Tursiops aduncus), classified as a new species since 1998, is underexplored in ecotoxicology owing to ethical constraints and the lack of specific in vitro models. Herein, we established the first skin fibroblast cell line (TaSF) from an Indo-Pacific bottlenose dolphin stranded along the Pearl River Estuary, China. TaSF cells exhibited strong proliferation in early passages but ceased mitosis at passage 19, likely owing to reaching the Hayflick limit. Morphology and immunofluorescence tests confirmed the fibroblastic nature of these cells. Karyotyping revealed 21 pairs of autosomes and 1 pair of sex chromosomes (XY), consistent with many cetaceans. To facilitate long-term future studies, TaSF cells were immortalized with exogenous simian virus 40 T antigen, creating the TaSFT cell line. The cytotoxic effects of 27 contaminants, including 6 organotins (OTs), 10 per- and polyfluoroalkyl substances (PFASs), and 11 phthalates (PAEs), on TaSFT cells were evaluated after 24-h exposure. Among these chemicals, OTs exhibited the strongest cytotoxicity, and both OTs and PFASs showed structure-related toxicity. These findings confirm the feasibility of TaSFT cells as a novel tool for ecotoxicity research on the Indo-Pacific bottlenose dolphin and highlight the need for further investigation into the environmental contaminant pressures on this species.

Highly efficient removal of trace thallium from surface water by Co@Fe Prussian blue analogue coated membrane

Super trace thallium(I) (Tl+) is still highly toxic and its removal from surface water is challenging. Here, we developed a new adsorptive membrane by immobilizing bimetal (cobalt and iron) Prussian blue analogues (Co@Fe-PBAs) on a polytetrafluoroethylene microporous membrane (Co@Fe-PBAs-M). The prepared membrane displayed precise adsorption of trace Tl+ (50 μg/L) from complex water. A variety of interfering factors, such as water pH, competitive adsorption of positive ions (Na+ and K+) and negative ions (CO32– and PO43-), natural organic matters (e.g., fulvic acid and bovine serum albumin) were evaluated during Tl removal. The composite membrane showed high removal efficiency (over 80 %) during long-term dynamic membrane separation of surface water containing super trace Tl+ (<2.0 μg/L), breaking through the adsorption limitation in ultralow concentration of Tl+. The unique bimetal electron transfer of Co@Fe-PBAs-M reinforced the adsorptive performance to Tl+ through dual ion exchange and intercalation. In the treatment of real Pearl River water containing 0.5 μg/L of Tl+, our membrane effectively reduced the Tl+ concentration to 0.04 μg/L during 6-h continuous separation, which was far below the required level for drinking water (i.e., 0.1 μg/L). This work offers a promising solution for safe drinking water by remedying ultralow Tl+ contaminated surface water.

Three genome assemblies of Opsariichthys bidens from Yangzte River, Pearl River and Qiantang River basins

Opsariichthys bidens is an endemic minnow, mainly distributed in China as an emerging aquaculture species. In this study, O. bidens collected from Yangzte River (YR), Pearl River (PR) and Qiantang River (QR) basins were used for karyotypic study and genome sequencing. Using PacBio long reads and Hi-C data, we assembled high-quality O. bidens genomes of 852.41 Mb (YR), 843.11 Mb (PR) and 840.94 Mb (QR) with scaffold N50 lengths of 21.01 Mb, 23.62 Mb and 24.75 Mb, respectively, of which 90.39%, 95.67% and 99.01% were anchored to 37, 38 and 39 chromosomes, respectively. 26,556 (YR), 25,036 (PR) and 26,283 (QR) protein-coding genes were predicted, respectively. The karyotype of O. bidens from YR, PR and QR were 2 N = 74 (6 m + 6sm + 4st + 58t), 2 N = 76 (4 m + 6sm + 4st + 62t) and 2 N = 78 (4 m + 4sm + 4st + 66t), respectively. Collinearity analysis and telomere predictions indicated that the observed chromosomal evolution was driven by Robertsonian translocation. These genome assemblies facilitate cryptic species determination, evolutionary study and genetic breeding of genus Opsariichthys.