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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.

Abstract Biodiversity credits are increasingly recognized as a potential instrument to incentivize and bolster efforts in biodiversity conservation. Nevertheless, their efficacy is impeded by a dearth of research. To mitigate these constraints, this study introduces a comprehensive and integrated framework for appraising biodiversity credits. Drawing upon the Emergy Accounting methodology, the framework encompasses four key perspectives: Emergy‐based Ecosystem Potential (EEP), Emergy‐based Ecosystem Network (EEN), Emergy‐based “Species' to Human” contributions (ESH), and Emergy‐based Species' Significance. Furthermore, this study scrutinizes the trajectory of biodiversity credits across 31 provinces spanning from 2000 to 2050, considering 220 distinct scenarios. The findings reveal that China has attained the no net loss (NNL) objective concerning conventional area‐based conservation targets, with forest cover encompassing 27% of the total land area. However, biodiversity credits at the ecosystem level exhibit an escalating trend, with growth rates ranging from 0.73% to 1.0%, while credits at the species level depict a decremental trend, with an approximate growth rate of −0.21%. Under a scenario of moderate growth, projections for the year 2030 indicate that the EEP credit is poised to accrue approximately 4.76E + 20 solar emjoules (sej), the EEN credit is forecasted to accumulate around 1.03E + 21 sej, and the ESH credit is anticipated to decline by 1.46E + 23 sej within the context of the NNL paradigm. These outcomes underscore the necessity of delineating differentiated biodiversity goals, and furnish insights into the dynamics of supply and demand pertaining to biodiversity credits within the ambit of offsetting schemes across the nation.

Surfactant-induced wetting impedes the practical implementation of membrane distillation (MD). Addressing this issue demands the development of an effective membrane cleaning strategy that can eliminate surfactants adhering to the membrane surface and restore the membrane hydrophobicity. However, current cleaning methods, such as direct drying and pressurized air backwashing, encounter challenges in thoroughly removing surfactants trapped within the pores while preserving the structural integrity of the membrane. This work presents a refined approach to conquer surfactant-induced wetting in MD by water flushing. Utilizing ultrasonic time domain reflectometry and optical coherence tomography techniques, we identified a critical cleaning depth and showed that the hydrophobicity of a partially wetted membrane can be fully recovered by water flushing when the wetting depth is below the critical threshold. Theoretical models evidenced that in instances of low water temperature and low flow rate conditions, relatively high critical cleaning depths can be realized, thereby expanding the operational scope for achieving complete hydrophobicity recovery. Our results demonstrated the applicability of water flushing to commercial membrane modules without necessitating any modification, emphasizing its substantial potential for advancing MD applications.

Abstract Unravelling biosphere feedback mechanisms is crucial for predicting the impacts of global warming. Soil priming, an effect of fresh plant-derived carbon (C) on native soil organic carbon (SOC) decomposition, is a key feedback mechanism that could release large amounts of soil C into the atmosphere. However, the impacts of climate warming on soil priming remain elusive. Here, we show that experimental warming accelerates soil priming by 12.7% in a temperate grassland. Warming alters bacterial communities, with 38% of unique active phylotypes detected under warming. The functional genes essential for soil C decomposition are also stimulated, which could be linked to priming effects. We incorporate lab-derived information into an ecosystem model showing that model parameter uncertainty can be reduced by 32–37%. Model simulations from 2010 to 2016 indicate an increase in soil C decomposition under warming, with a 9.1% rise in priming-induced CO2 emissions. If our findings can be generalized to other ecosystems over an extended period of time, soil priming could play an important role in terrestrial C cycle feedbacks and climate change.

Abstract Mariculture has been gradually regarded as an important solution to the global food production crisis. Increasing scientific evidence reveals that mariculture can provide a large number of ecologic benefits, in accordance with several United Nations sustainable development goals. However, previous studies mostly focused on the negative impacts of mariculture, which may impede its increased production. Here, based on Emergy Accounting (EMA), we propose a comprehensive “Multiple Inputs‐Ecosystem Service Multifunctionality‐Multiple Environmental Impacts” (MI‐ESM‐MEI) evaluation framework, trying to describe mariculture's overall environmental performances beyond just limiting to the production of seafoods. As the world's largest mariculture producer, China is taken as an example for evaluation. Our results show that both cultured species and cultivation patterns determine the environmental performance of mariculture: seaweed‐raft, shellfish‐raft, shellfish‐hanging cage, shellfish‐bottom sowing and others‐bottom sowing mariculture could be more influential in environmental support. By identifying priority areas for offshore mariculture development, ecological benefits can be significantly improved using about 27% of China's territorial sea area. At present, mariculture in Liaoning, Shandong, Jiangsu, and Zhejiang performs better than that in other regions. Under the condition of recognizing nonnegligible ecological benefits of mariculture, additional improvements for more sustainable development are urgently needed. In addition, mariculture activities especially seaweed mariculture can help solve water contamination problem and alleviate the effects of eutrophication on coastal ecosystems. For most China coastal regions, if integrated multi‐trophic aquaculture (IMTA) mode can be promoted, the ecological burden of mariculture can be reduced and even converted into ecological benefit.

Abstract Atmospheric polycyclic aromatic hydrocarbons (PAHs), which are emitted significantly by economic sectors, are closely related to the global incidence of human cancer. When assessing temporal changes in PAH emissions in a country that is vast in area, such as China, it is crucial to consider socioeconomic differences across geological regions. In this study, we developed PAH emission factors at the provincial level and used them to compile a Chinese PAH emission inventory. Subsequently, we estimated trade‐driven PAH emissions at the provincial level in 2007, 2010, 2012, 2015, and 2017, and examined the critical supply chain paths. The updated inventory reveals a distinct temporal trend in trade‐driven PAH emissions, although they remain at an order of magnitude similar to previous estimates. National total production‐, consumption‐, and income‐based PAH emissions, despite a rebound in 2012, exhibit a general decline from 59.3, 43.3, and 48.8 kt in 2007 to 52.1, 43.9, and 47.0 kt in 2017, respectively. These declines align with economic adjustments and emissions mitigation legislation. Spatial hotspots were concentrated in the most affluent Yangtze River Delta, Pearl River Delta, and Jing‐Jin‐Ji provinces on the demand side and in the northern coal resource‐rich provinces on the supply side. They primarily drive PAH emissions from the heavy industrial sectors of northern coal resource‐rich provinces. Fewer affluent provinces have experienced a rapid increase in trade‐driven PAH emissions after 2012, emphasizing the need for synergistic reduction measures to combat PAH pollution.

Summary: China has committed to eradicating the forage-livestock conflict (FLC) by 2035 to restore degraded rangelands. This commitment is accompanied by China’s rapid socioeconomic development, highlighting the necessity to analyze the effects of socioeconomic transition on FLC changes. Here, we uncover multi-regional socioeconomic drivers of China’s FLC changes. The results show that during 2005–2015, the economic structure transition of China has cumulatively driven 24 Mt of FLC reductions. In particular, the FLC reduction driven by the final demand structure transition of pastoral provinces is three times that of non-pastoral provinces. The mitigation effects of the final demand structure transition of external regions generally decrease with increasing distance from the certain pastoral province. The FLC reduction caused by the production structure transition of non-pastoral provinces is twice that of pastoral provinces. This study highlights the significance of interregional cooperation and economic structure optimization to achieve China’s “Forage-Livestock Balance Goal 2035.” Science for society: Forage-livestock conflict (FLC) is a major anthropogenic driver of rangeland degradation in China. It poses serious threats to environmental, economic, and social sustainability due to its harmful impacts on ecosystem services, livestock development, and pastoralists’ well-being. To combat rangeland degradation, China has adopted a series of in situ FLC control measures and set a goal to eradicate FLC by 2035. Grazing in pastoral areas and associated FLCs are significantly affected by local and remote socioeconomic development. Using a numerical model that accounts for multi-regional socioeconomic changes, we find that the national economic structure transition has led to FLC reductions during 2005–2015. The final demand structure change of non-pastoral provinces and production structure change of pastoral provinces have mitigation potentials to be tapped. The outcome can support interregional cooperation and economic structure transition to achieve China’s zero-FLC goal.

Abstract As human consumption expands, four environmental footprints (EFs) exceed the planetary boundaries (PBs) at the global scale. Managing absolute environmental sustainability (AES) based on PBs and EFs at the subnational level is crucial for policy insights. However, a consumption‐based AES management framework still needs to be developed. A framework, including five nexus environmental pressures embodied in the supply chain, was developed and tested in our study across China's 30 provinces to address this knowledge gap. The framework involved three steps: (a) assessing AES for five environmental pressures, (b) measuring environmental surplus and overshoot and composition of EFs, and (c) identifying priority areas for AES management. The results showed that only some provinces are sustainable for three impact‐oriented indicators, especially those with larger populations. Moreover, the embodied environmental pressure mainly flows from the Northwest to Southeast China. For two resource‐oriented indicators, over 74% of provinces are absolutely sustainable. From a nexus perspective, Shandong and Shanghai are identified as priorities for AES management due to their low IESI values of 0.32, 0.33, and 0.40, respectively, which means the worst performance. To improve their IESI, Shanghai needs to control the consumption of blue water‐intensive products, while Shandong and Henan should consume fewer CO2 emissions and N‐ and P‐loss‐intensive products. This framework can clarify subnational responsibilities of environmental overshoots, guide sustainable development, and be widely used at the subnational level in countries worldwide.

Biodegradable plastic, a widely used ecofriendly alternative to conventional plastic, easily form nanoplastics (NPs) upon environmental weathering. However, the effects and underlying mechanisms governing the toxicity of photoaged biodegradable NPs to aquatic insects are not understood. In this study, we investigated the photoaging of polylactic acid nanoplastics (PLA-NPs, a typical biodegradable plastic) that were placed under xenon arc lamp for 50 days and 100 days and compared the toxicity of virgin and photoaged PLA-NPs to Chironomus kiinensis (a dominant aquatic insect). The results showed that photoaged PLA-NPs significantly decreased the body weight, body length and emergence rate of C. kiinensis. Additionally, photoaged PLA-NPs induced more severe gut oxidative stress, histological damage, and inflammatory responses than virgin PLA-NPs. Furthermore, the alpha diversity of gut microbiota was lower in photoaged PLA-NPs group than virgin PLA-NPs. The relative abundance of key gut bacteria related to intestinal barrier defense, immunity, and nutrient absorption was reduced more significantly in photoaged PLA-NPs group than virgin PLA, indirectly leading to stronger gut damage and growth reduction. A stronger impact of photoaged PLA-NPs on the gut and its microbiota occurred because photoaging reduced the size of NPs from 255.5 nm (virgin PLA) to 217.1 nm (PLA-50) and 182.5 nm (PLA-100), induced surface oxidation and enhancement of oxidative potential, and improved the stability of NPs, thereby exacerbating toxicity on the gut and its microbiota. This study provides insights into the effects of biodegradable NPs on aquatic insects and highlights the importance of considering biodegradable nanoplastic aging in risk assessments.

Abstract Background Silicosis is an important occupational disease caused by inhalation of free silica and is characterized by persistent pulmonary inflammation, subsequent fibrosis and lung dysfunction. Until now, there has been no effective treatment for the disease due to the complexity of pathogenesis. Fermented cordyceps powder (FCP) has a similar effect to natural cordyceps in tonifying the lung and kidney. It has started to be used in the adjuvant treatment of silicosis. This work aimed to verify the protective effects of FCP against silicosis, and to explore the related mechanism. Methods Wistar rats were randomly divided into four groups including the saline-instilled group, the silica-exposed group, the silica + FCP (300 mg/kg) group and the silica + FCP (600 mg/kg) group. Silicosis rat models were constructed by intratracheal instillation of silica (50 mg). Rats in the FCP intervention groups received the corresponding dose of FCP daily by intragastric gavage. Rats were sacrificed on days 7, 28 and 56 after treatment, then samples were collected for further analysis. Results FCP intervention reduced the infiltration of inflammatory cells and the concentration of interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and transforming growth factor-β1 (TGF-β1) at days 7, 28, 56, and decreased the expression of collagen, α-smooth muscle actin (α-SMA) and fibronectin (FN) at days 28 and 56 in the lung of silicosis rats. FCP also decreased the immune response of Th1 and Th17 at days 7, 28, 56 and inhibited the enhancement of the Th2 response at day 56. Conclusions FCP intervention could alleviate silica-induced pulmonary inflammation and fibrosis, the protective effect may be achieved by reducing Th1 and Th17 immune responses and inhibiting the enhancement of the Th2 response.

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.

The impacts of the availability and spatial configuration of urban green spaces (UGS) on their cooling effects can vary with background climate conditions. However, large-scale studies that assess the potential heterogeneous relationships of UGS availability and spatial configuration with urban thermal environment are still lacking. In this study, we investigated the impacts of UGS availability and spatial configuration on urban land surface temperature (LST) taking 306 cities in China as a case study covering a multi-biome-scale. We first calculated the availability of surrounding UGS for urban built-up pixels in each city using a distance-weighted approach, and its spatial configuration was quantified through the Gini coefficient. Then, we employed various regression models to explore how the impacts of UGS availability and the Gini coefficient on LST varies across different LST quantiles and between day- and nighttime. The results revealed that UGS availability was negatively associated with both daytime and nighttime LST, while the Gini coefficient showed a positive impact solely on daytime LST, indicating that an adequate and equally distributed UGS contributes to lower environmental temperatures during the daytime. Furthermore, the impact of UGS availability on LST decreased during both day- and nighttime with increased background LST quantiles. Whereas the impact of the Gini coefficient increased only with daytime LST quantile levels, with its effect remaining almost insignificant during the night. Our findings provide new insights into the impacts of UGS on urban thermal environment, offering significant implications for urban green infrastructure planning aiming at lowering the urban heat island.

Abstract Biodegradable plastic is often perceived as a possible solution for microplastic (MP) pollution. Photodegradation is an important transformation pathway of biodegradable MPs in aquatic environments. However, the influence mechanisms of dissolved organic matter (DOM) from different sources on photodegradation of biodegradable MPs are poorly understood. This study explored the role of naturally and pyrogenically sourced DOM in the photodegradation of polylactic acid (PLA) MPs. The aromatics of natural DOM (NDOM) were higher than those of biochar-sourced DOM (BDOM) and showed a stronger improvement in PLA-MPs degradation, as evidenced by particle size reduction, crystallinity increase and polymerization decrease, breakage of surface morphology, and increase in oxygen-containing functional groups on MPs’ surface (O/C increase: 65.1% for NDOM; 34.9% for BDOM). Reactive oxygen species analysis showed that the excited triplet states of DOM (3DOM*) generated by NDOM produced more •OH and 1O2 than that of BDOM, accelerating PLA-MPs photodegradation. Such photodegradation processes were further enhanced through the sorption of DOM by PLA-MPs, in which non-aromatic components were preferentially sorbed, causing the enrichment of aromatics in the solution, leading to more 3DOM* formation. This study improves the understanding of the migration and transformation of biodegradable MPs with the presence of DOM. Graphical Abstract

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.

Abstract Green roofs affect the urban food-water-energy nexus and have the potential to contribute to sustainability. Here we developed a generalizable methodology and framework for data-sparse cities to analyze the food-water-energy nexus of green roofs. Our framework integrates the environmental costs and benefits of green roofs with food-water-energy systems and makes it possible to trace energy-water-carbon footprints across city boundaries. Testing the framework in São José dos Campos (SJC), Brazil and Johannesburg, South Africa, we found that green roofs are essentially carbon neutral and net energy consumers from a life cycle perspective. SJC is a net water beneficiary while Johannesburg is a net water consumer. Rainwater utilization could save irrigated water, but requires 1.2 times more energy consumption. Our results show that SJC and Johannesburg could direct their green roof development from local food production and energy saving, respectively and highlight opportunities for green roof practices in cities.

The optimal tuning of high-order motion parameters has emerged as a promising strategy for actively controlling the kinematics/dynamics of high-speed cam mechanisms. However, accomplishing this task remains challenging with current low-order interpolation or tuning methods. This study proposes an integrated high-order interpolation and tuning methodology for the optimal construction of high-speed motion curves. Initially, an explicit C4-spline interpolant (C4SI) is developed. This interpolant utilizes four-order continuous (C4) splines to synthesize a high-fidelity motion curve that satisfies the predefined motion constraints up to the fourth order, including dimensionless displacement, velocity, acceleration, jerk, and quirk. Concerning the reduction of motion peaks, a unique C4SI-based global kinematics optimization strategy is designed, using the definite integral of the motion curve (free of the time variable) as the objective function. This facile time-free optimization strategy could yield a simultaneous reduction in multiple motion peaks (up to five), which is currently inaccessible with conventional motion tuning strategies. Concerning the improvement of dynamic characteristics, the C4SI-based time-free global dynamics optimization of variable motion parameters is further performed. The results indicate that the optimized fourth-order motion curve offers minimal high-speed transmission error and residual vibration over the whole rise-dwell-return-dwell cycle, which outperforms the standard motion curves and other low-order counterparts.

Abstract Methane seepage, generated from natural processes or gas hydrate dissociation, drives the development of cold seep ecosystems and leads to atmosphere methane emission, thereby influencing climate change. Uncovering the intrinsic interactions among methane seepage intensities, biogeochemical processes in the sediment, and benthic community characteristics at the seafloor is essential to clarify and predict the ultimate fate of methane leakage from the deep sea. Here, we conducted a systematic investigation of methane intensity, pore fluid migration characteristics, sediment mineral fraction features, and the evolution of biological communities in areas with different methane intensities. Furthermore, analyses of high‐resolution images, pore fluid geochemical feature, and lithologic characteristics of the sediment in the Haima cold seep were also carried out in this study. The results showed that, in areas with different methane intensities, organic matter sulfate reduction and anaerobic oxidation of methane were heterogeneous. The heterogeneity led to the methane transformation zones at different depths, which changed the mineral composition of the sediment and biological communities in the seabed. In addition, a hypothesis of successional sequence of biomes in cold seep was established. This study revealed that the methane seepage intensity was a key factor in determining the biogeochemical process in the sediment of cold seep. The coupling effects of biogeochemical processes and methane seepage intensities dominated the community succession of cold seep. These findings could provide important implications for understanding the dynamic deep marine methane cycle mechanism and the contribution of deep‐sea methane released to climate change.

IntroductionGlobal warming is caused by greenhouse gases (GHGs). It has been found that the release of methane (CH4) from Arctic permafrost, soil, ocean, and sediment is closely related to microbial composition and soil factors resulting from warming over several months or years. However, it is unclear for how long continuous warming due to global warming affects the microbial composition and GHG release from soils along Arctic glacial meltwater rivers.MethodsIn this study, the soil upstream of the glacial meltwater river (GR) and the estuary (GR-0) in Svalbard, with strong soil heterogeneity, was subjected to short-term field incubation at 2°C (in situ temperature), 10°C, and 20°C. The incubation was carried out under anoxic conditions and lasted for few days. Bacterial composition and CH4 production potential were determined based on high-throughput sequencing and physiochemical property measurements.ResultsOur results showed no significant differences in bacterial 16S rRNA gene copy number, bacterial composition, and methanogenic potential, as measured by mcrA gene copy number and CH4 concentration, during a 7- and 13-day warming field incubation with increasing temperatures, respectively. The CH4 concentration at the GR site was higher than that at the GR-0 site, while the mcrA gene was lower at the GR site than that at the GR-0 site.DiscussionBased on the warming field incubation, our results indicate that short-term warming, which is measured in days, affects soil microbial composition and CH4 concentration less than the spatial scale, highlighting the importance of warming time in influencing CH4 release from soil. In summary, our research implied that microbial composition and CH4 emissions in soil warming do not increase in the first several days, but site specificity is more important. However, emissions will gradually increase first and then decrease as warming time increases over the long term. These results are important for understanding and exploring the GHG emission fluxes of high-latitude ecosystems under global warming.

China has made great efforts to fight environmental contamination along with rapid development and industrialization over the past few decades. However, the effects of these nationwide measures, such as energy restructuring, on pollutant residuals in soil have not been well quantified. Polycyclic aromatic hydrocarbon (PAH) pollution is a major concern around the world, and PAH emissions are associated with the energy structure. Therefore, we speculated that the adjustment of the energy structure in China may reduce the content of PAHs in soil. To test this hypothesis, we measured the concentrations of sixteen US Environmental Protection Agency (US EPA) priority PAH compounds (Σ16PAHs) at 54 soil sampling sites in Beijing in 2008 and 2019 and compiled nationwide data for 1704 soil sampling sites in the past two decades. The results showed that the Σ16PAH concentrations descended along the urban–suburban–rural–background gradient, and they first increased with increasing gross regional production (GRP) and plateaued when the GRP reached a certain level. The average Σ16PAH concentrations showed a decreasing trend across China over the past 20 years, and they decreased significantly from 22.7 μg·g−1 total organic carbon (TOC) in 2008 to 10.0 μg·g−1 TOC in 2019 in Beijing. The source identification analyses inferred that the decreasing trend of soil PAHs was due to the declines in the consumption of coal, coke, and some oils and the rising consumption of clean energy, such as electricity and natural gas, in China. This study demonstrates the important role of adjusting the energy structure in decreasing soil PAH concentrations and improving soil environmental quality.

Summary: Photocatalytic microplastics (MPs) conversion into valuable products is a promising approach to alleviate MPs pollution in aquatic environments. Herein, we developed an amorphous alloy/photocatalyst composite (FeB/TiO2) that can successfully convert polystyrene (PS) MPs to clean H2 fuel and valuable organic compounds (92.3% particle size reduction of PS-MPs and 103.5 μmol H2 production in 12 h). FeB effectively enhanced the light-absorption and carrier separation of TiO2, thereby promoting more reactive oxygen species generation (especially ‧OH) and combination of photoelectrons with protons. The main products (e.g., benzaldehyde, benzoic acid, etc.) were identified. Additionally, the dominant PS-MPs photoconversion pathway was elucidated based on density functional theory calculations, by which the significant role of ‧OH was demonstrated in combination with radical quenching data. This study provides a prospective approach to mitigate MPs pollution in aquatic environments and reveals the synergistic mechanism governing the photocatalytic conversion of MPs and generation of H2 fuel.

Hematite, as an extensive natural mineral with multiple crystal facets, profoundly affects the migration and transformation of pollutants in the natural environment. However, little is known about the photochemical behavior of microplastics on different facets of hematite in the aquatic environment. In this work, the photoaging of polystyrene microplastics (PS-MPs) on different crystal planes ({001}, {100}, and {012} facets) and related mechanisms were studied. Two-dimensional correlation spectroscopy analysis illustrated that the reaction pathways of PS-MPs photoaging on hematite tended to preferential chemical oxidization. The stronger performance of PS-MPs photoaging, expressed by particle size reduction and surface oxidation, was observed on the {012} crystal facet. Under irradiation, {012} facet-dominated hematite with a narrower bandgap (1.93 eV) reinforced the photogenerated charge carrier separation, and the lower activation energy barrier (1.41 eV calculated from density functional theory) led to effective •OH formation from water oxidation. These findings elucidate the underlying photoaging mechanism of MPs on hematite with different mineralogical phases.

Folate-mediated one-carbon metabolism (FOCM) is closely associated with postharvest preservation. This study investigated the effects of exogenous nitric oxide (NO) on FOCM, storage quality, energy metabolism, and mitochondrial membrane integrity in cold-storage peach fruit. In this experiment, peaches were soaked with 1.5 mmol L−1S-nitrosoglutathione (GSNO) as NO donor, and the negative treatment (NT) solution containing 5 μmol L−1 carboxy-PTIO (c-PTIO, NO scavenger), 200 μmol L−1 NG-Nitro-L-arginine methyl ester (L-NAME, NO synthase-like enzyme inhibitor), and 200 μmol L−1 sodium tungstate dihydrate (nitrate reductase inhibitor) and stored at 0°C. The results showed that NO decreased the activity of S-adenosylmethionine synthase and S-adenosylhomocysteine hydrolase and increased the activity of methionine sulfoxide reductase A, as well as the content of N5-methyl-THF, the ratio of tetrahydrofolate (THF), homocysteine, methionine, S-adenosylmethionine (SAM), and SAM to S-adenosylhomocysteine compared with the control, indicating that NO effectively increased FOCM flux by affecting the activity of FOCM enzymes. Meanwhile, NO increased the activities of H+-ATPase, Ca2+-ATPase, cytochrome c oxidase, succinate dehydrogenase, and the contents of adenosine triphosphate and adenosine diphosphate, and maintained high energy charge in peaches during storage. NO retarded the increase in mitochondrial permeability transition, reactive oxygen species content, and the decrease in mitochondrial membrane fluidity, membrane potential, and swelling. NT treatment exhibited the opposite results. In conclusion, these results suggested that NO could induce the accumulation of folate and FOCM flux and maintain mitochondrial energy levels, which might be responsible for maintaining the quality of peaches during cold storage.

Abstract Microplastic (MP) pollution is one of the greatest threats to marine ecosystems. Cold seeps are characterized by methane‐rich fluid seepage fueling one of the richest ecosystems on the seafloor, and there are approximately more than 900 cold seeps globally. While the long‐term evolution of MPs in cold seeps remains unclear. Here, how MPs have been deposited in the Haima cold seep since the invention of plastics is demonstrated. It is found that the burial rates of MPs in the non‐seepage areas significantly increased since the massive global use of plastics in the 1930s, nevertheless, the burial rates and abundance of MPs in the methane seepage areas are much lower than the non‐seepage area of the cold seep, suggesting the degradation potential of MPs in cold seeps. More MP‐degrading microorganism populations and functional genes are discovered in methane seepage areas to support this discovery. It is further investigated that the upwelling fluid seepage facilitated the fragmentation and degradation behaviors of MPs. Risk assessment indicated that long‐term transport and transformation of MPs in the deeper sediments can reduce the potential environmental and ecological risks. The findings illuminated the need to determine fundamental strategies for sustainable marine plastic pollution mitigation in the natural deep‐sea environments.

Lidar has emerged as an important technology for the high-precision three-dimensional remote sensing of the ocean. While oceanic lidar has been widely deployed on various platforms, its underwater deployment is relatively limited, despite its significance in deep-sea exploration and obstacle avoidance for underwater platforms. Underwater lidar systems must meet stringent requirements for high performance, miniaturization, and high integration. Single-photon lidar, by elevating the detection sensitivity to the single-photon level, enables high-performance detection under the condition of a low-pulse-energy laser and a small-aperture telescope, making it a stronger candidate for underwater lidar applications. However, this imposes demanding requirements for the data acquisition system utilized in single-photon lidar systems. In this work, a self-developed multi-channel acquisition system (MCAS) with a high-resolution and real-time histogram statistics capability was developed. By utilizing field-programmable gate array (FPGA) technology, a method that combines coarse counters with multi-phase clock interpolation achieved an impressive resolution of 0.5 ns and enabled a time of flight duration of 1.5 μs. To address counting instability, a dual-counter structure was adopted in the coarse counter, and real-time histogram statistics were achieved in the data acquisition system through a state machine. Furthermore, the non-uniform phase shift of the clock was analyzed, and a correction algorithm based on code density statistics was proposed to mitigate the periodic modulation of the backscattered signal, with the effectiveness of the algorithm demonstrated through experimental results. The robustness and stability of the MCAS were validated through an underwater experiment. Ultimately, the development of this compact acquisition system enables the implementation of underwater single-photon lidar systems, which will play a crucial role in underwater target imaging, obstacle avoidance in underwater platforms, and deep-sea marine environment monitoring.

The Monte Carlo (MC) simulation, due to its ability to accurately simulate the backscattered signal of lidar, plays a crucial role in the design, optimization, and interpretation of the backscattered signal in lidar systems. Despite the development of several MC models for lidars, a suitable MC simulation model for underwater single-photon lidar, which is a vital ocean remote sensing technique utilized in underwater scientific investigations, obstacle avoidance for underwater platforms, and deep-sea environmental exploration, is still lacking. There are two main challenges in underwater lidar simulation. Firstly, the simulation results are significantly affected by near-field abnormal signals. Secondly, the simulation process is time-consuming due to the requirement of a high number of random processes to obtain reliable results. To address these issues, an algorithm is proposed to minimize the impacts of abnormal simulation signals. Additionally, a graphics processing unit (GPU)-accelerated semi-analytic MC simulation with a compute unified device architecture is proposed. The performance of the GPU-based program was validated using 109 photons and compared to a central processing unit (CPU)-based program. The GPU-based program achieved up to 68 times higher efficiency and a maximum relative deviation of less than 1.5%. Subsequently, the MC model was employed to simulate the backscattered signal in inhomogeneous water using the Henyey–Greenstein phase functions. By utilizing the look-up table method, simulations of backscattered signals were achieved using different scattering phase functions. Finally, a comparison between the simulation results and measurements derived from an underwater single-photon lidar demonstrated the reliability and robustness of our GPU-based MC simulation model.

Permafrost soils can be substantial sources of nitrous oxide (N2O) to the atmosphere, but no data exist on the N2O footprints of permafrost rivers. Here, the authors show that alpine permafrost rivers are unexpectedly small sources of atmospheric N2O at present.

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.;

ABSTRACT We found a new qnr gene, qnrVF1, carried by a multidrug resistance plasmid in a clinical Vibrio furnissii isolate. QnrVF1 exhibits 44.6% to 72.5% similarity in identity with other Qnr family proteins. QnrVF alleles are mainly encoded by chromosomes of V. furnissii and Vibrio fluvialis. Phylogenic analysis showed that QnrVF1 and QnrVF2 form a distinct clade in Qnr proteins. Thus, qnrVF represents a new qnr family. In addition, the qnrVF1 gene is often flanked by the mobile element ISCR1. Thus, it is likely that qnrVF1 is mobilized by ISCR1 from chromosome to plasmid in V. furnissii. IMPORTANCE Quinolones are widely used drugs. Bacteria contain a quinolone resistance gene, which mediates resistance to quinolones. Currently, seven families of Qnr proteins, QnrVC, QnrA, QnrB, QnrC, QnrD, QnrE, and QnrS, have been identified. However, it is unclear whether there are any other qnr families. In this study, we identified a new qnr family, qnrVF. We found many V. furnissii and V. fluvialis strains that possess chromosomal qnrVF alleles, suggesting that V. furnissii and V. fluvialis are the reservoirs of qnrVF. We also found that QnrVF1 confers low-level resistance to quinolones. ISCR1 may facilitate the spread of qnrVF1. The emergence and spread of qnrVF may pose a considerable threat to public health.

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 amounts of marine debris and plastic pollution have been growing dramatically in the environment. Floating marine debris can be transported between the sea and coastal zone by various processes. However, it remains unknown if marine debris in the sea and coastal zone are quantitatively related. This study collected time-series data on marine debris (including plastics) from China’s beaches and adjoining seas over a 10-year period (2012–2021). It aims to investigate (1) the characteristics of debris distribution in the beach-sea continuum, (2) the relationships among the density and accumulation density of marine debris on beaches, sea surfaces and seafloors. Our results show that the density of marine debris and plastics on beaches and seafloors in the pandemic period were 3–5 folds of those in the pre-pandemic period. The density (104682.4 ± 27793.0 items km–2) and accumulation density (1787.4 ± 220.0 kg km–2) of marine debris on beaches were significantly higher than those on both sea surfaces (3320.8 ± 446.0 items km–2 and 21.6 ± 5.7 kg km–2) and seafloors (2453.7 ± 868.4 items km–2 and 117.5 ± 70.4 kg km–2). The density of plastics on beaches (85373.0 ± 21633.8 items km–2) was significantly higher than that on sea surfaces (2915.4 ± 365.8 items km–2) and seafloors (2254.2 ± 717.1 items km–2). The density of small-to-medium (0–10cm) floating debris (3419.5 ± 418.2 items km–2) was more than 100 times higher than the density of large (> 10cm) floating debris (29.6 ± 3.1 items km–2). The proportion of plastics in marine debris on sea surfaces (83.3 ± 1.3%) was significantly higher than that on beaches (74.1 ± 2.5%) but not significantly different from that on seafloors (81.1 ± 3.0%). There are significant relationships between the density of debris on seafloors and that on beaches, between the density or accumulation density of debris on seafloors and that on sea surfaces. This study suggests that the density and accumulation density of marine debris on seafloors were closely associated with those on sea surfaces and beaches. The results can help to estimate the transportation, deposition and aggregation of marine debris from beaches and sea surfaces to seafloors.

Taking the Permian Fengcheng Formation of the Mahu Sag of the Junggar Basin as an example, a systematic study of shale oil was carried out for the occurrence states and potential influencing factors by integrating various data including cores, well logging, X-ray diffraction, argon ion polishing and field emission-scanning electron microscopy (FE-SEM) observations, high-pressure mercury injection (HPMI), rock pyrolysis, and two-dimensional nuclear magnetic resonance (NMR) experiments. The shale oil of the Fengcheng Formation in the Mahu Sag mainly has two modes of occurrence: film-like adsorbed oil and infilled free oil. The main constrains for shale oil occurrence state include lithofacies association, mineral composition and reservoir space. Four lithofacies associations namely dolomitic shale, sandy shale-dolomitic siltstone, dolomite rock containing alkaline mineral-argillaceous siltstone, and siliceous dolomite rock-dolomitic siltstone were recognized in the shale reservoirs of the Fengcheng Formation. The mineral composition, reservoir space, micro-pore structure and shale oil occurrence states of different lithofacies appeared to be quite different. The contents of quartz, pyrite and organic matter were positively correlated with thermal cracking hydrocarbon (S2), and the contents of feldspar and dolomite showed a weak positive correlation with free hydrocarbon (S1). The free oil was mainly stored in mesopores and large pores, such as secondary dissolution pores and residual intergranular pores. The absorbed oil was mainly stored in mesopores and small pores, such as organic pores, intercrystallite pores and the surface of mineral particles. The mineral composition and pore-throat structure were dominant factors controlling the occurrence state of shale oil.

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.

Summary: Substantial evidence indicates that China’s afforestation statistically contributed to the ecosystem services (ES) improvement. However, we found the potential challenges behind this improvement, especially in water-limited areas. We propose an attribution analysis method, which can assess the specific contribution of natural, human and cognition degree drivers to ES dynamics. The results found that the ratio of natural and human drivers in the area north of China’s 400 mm precipitation isopleth is 2:7. This means local vegetation capacity has already exceeded water limitation, implying a conflict between nature and humans. However, the natural contribution in the area between 400 and 800 mm precipitation isopleth is negative, whereas the human contribution is 91%. This means this area has fragile natural conditions and needs more flexible policies. The ratio of natural and human drivers in the region south of 800 mm precipitation isopleth is 6:3, suggesting the ecological policies here can be maintained.

Land–sea interactions in coastal wetlands create heterogeneous vegetated habitats with regular zonation along a topographic gradient. However, it’s unclear how the trophic diversity of communities and trophic structure of food webs change along the gradient. Here, we investigated the empirically resolved food web structure and trophic diversity across four vegetated habitats (Phragmites australis, Suaeda salsa, Spartina alterniflora, and Zostera japonica seagrass) along a gradient from upland to near-shore waters in the Yellow River Delta wetland. We quantified δ13C and δ15N of carbon sources (detritus, primary producers) and consumers (zooplankton, macroinvertebrates, fish). δ13C and δ15N of the carbon sources and consumers differed significantly among the four habitats. Carbon sources and consumers became more 13C-enriched and 15N-enriched along the gradient, respectively. The consumer trophic position was higher in the S. salsa habitat than in the seagrass habitat, followed by the S. alterniflora and P. australis habitats. The habitat formed by invasive S. alterniflora had the lowest corrected standard ellipse areas in the δ13C vs. δ15N plots for the basal carbon sources and all consumers combined, and the lowest Layman community metrics for the δ13C range, total area, and centroid distance; thus, trophic groups in this habitat had the lowest isotopic trophic diversity. Using a Bayesian isotope mixing model, we found that consumer diet compositions differed greatly among the habitats where the consumer was present, except for shrimps and polychaetes. Food web topological properties (species richness, number of trophic links, linkage density, proportions of intermediate consumers and omnivores) increased along the gradient. Generally, habitat heterogeneity created highly variable food webs. Our results provide insights into the spatial variation in coastal ecosystems along a topographic gradient, and demonstrate the need to protect habitat heterogeneity in coastal wetlands, combined with adaptive management to control invasive species.

Carbon gas flux is important for studies on carbon dynamics in mangroves, but the controlling factors have not always been sufficiently understood. In this study, it is suggested that sediment carbon dioxide (CO2) fluxes in a natural mangrove in Southern China are controlled by tidal positions, seasons, species, the densities of crab burrows and pneumatophores, light conditions and sediment temperature. All these factors account for 51.47% variation in CO2 flux from the sediment–air interface. CO2 flux generally decreased along the tidal position from landward to seaward, and was higher in the dry season than in the wet season. CO2 flux was highest in Avicennia marina (grey mangrove) in comparison with Aegiceras corniculatum (river mangrove) and Kandelia obovata. Pneumatophores and crab burrows promoted sediment CO2 flux in the mangrove at a rate of 18.29 and 15.52 mmol m−2 d−1. Dark flux was higher than light flux. Sediment temperature has a negative influence on CO2 flux. Pneumatophores explain the most variation (13.9%) in CO2 flux among the above factors. Our study suggests that the photosynthesis activity of microphytobenthos is an important factor driving the change of CO2 emissions in this natural mangrove. This is of great significance for the study and for the full exploitation of the carbon sink potential of mangroves.

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.

With the rapid development of distributed transactional databases in recent years, there is an urgent need for fair performance evaluation and comparison. Though there are various open-source benchmarks built for databases, it is lack of a comprehensive study about the applicability for distributed transactional databases. This paper presents a review of the state-of-art benchmarks with respect to distributed transactional databases. We first summarize the representative architectures of distributed transactional databases and then provide an overview about the chock points in distributed transactional databases. Then, we classify the classic transactional benchmarks based on their characteristics and design purposes. Finally, we review these benchmarks from schema and data definition, workload generation, and evaluation and metrics to check whether they are still applicable to distributed transactional databases with respect to the chock points. This paper exposes a potential research direction to motivate future benchmark designs in the area of distributed transactional databases.