环境科学最新文献

Wetland sediments are the "sinks" of microplastics， nitrogen， phosphorus， and other nutrient elements in freshwater ecosystems， while microplastics have a great impact on the environment. To explore the effects of different types and contents of microplastics on nitrogen and phosphorus elements in the sediments of Zhalong wetland， an internationally important wetland， a total of seven experimental groups were set up， including CK （without microplastic addition）， PE2 （2% polyethylene microplastics）， PE5 （5% polyethylene microplastics）， PE10 （10% polyethylene microplastics）， PLA2 （2% polylactic acid microplastics）， PLA5 （5% polylactic acid microplastics）， and PLA10 （10% polylactic acid microplastics）. Culture experiments were conducted for 7， 15， and 30 days to determine total nitrogen， ammonium nitrogen， nitrate nitrogen， total phosphorus， organic phosphorus， and inorganic phosphorus in Zhalong wetland sediments. The results showed that the addition of microplastics significantly decreased the pH of Zhalong wetland sediments （P<0.05）， in which the pH of sediments decreased with the increase in PE and PLA microplastics contents， and the response to PLA microplastics was stronger. Compared with that in the blank control group， the microplastic treatment group decreased the ammonium nitrogen content and increased the nitrate nitrogen content in the sediments of Zhalong wetland， and the ammonium nitrogen content in the sediments of the PLA microplastic treatment group decreased the most， ranging from 30.1%-50.5%. The contents of ammonium nitrogen and nitrate nitrogen were negatively correlated with the content of microplastics （P<0.001） and positively correlated with the content of microplastics （P<0.05）. The addition of microplastics significantly decreased organophosphate （P<0.05） and increased inorganic phosphorus （P<0.05） in Zhalong wetland sediments. In addition， the experimental analysis showed that the addition of PE plastic mainly affected the nitration and organic phosphate mineralization by changing the pH of the sediment. The effects of PLA microplastics on nitrogen and phosphorus in Zhalong wetland sediments were mainly related to their contents. The results of this study provide basic data for the prevention and control of microplastic pollution and the protection and restoration of Zhalong wetland， as well as provide relevant references for the effects of microplastics on nitrogen and phosphorus in wetland sediments.

The aim of this study was to explore the effects of different fertilization measures on nutrients and winter wheat yield in brown soil fields， analyze the characteristics of soil extracellular enzymes and microbial communities， and provide a theoretical basis for effectively improving soil fertility and winter wheat yield in brown soil fields. Based on seven consecutive years of positioning tests from 2017 to 2024， including five different fertilization measures， soil nutrient content， extracellular enzyme activity， and bacterial and fungal community structure and function were analyzed by using high-throughput sequencing technology and the ecological network method in a no fertilization treatment （CK）， conventional fertilization treatment （NPK）， optimized fertilization treatment （NPKM）， single organic fertilizer treatment （OM）， and conventional fertilization + straw direct return treatment （NPKS）. The results showed that：① Different fertilization measures （NPK， NPKM， NPKS， and OM） could improve soil fertility， wheat yield， and extracellular enzyme activity， among which the NPKS treatment had the most significant effect. ② Different fertilization measures changed the composition of the soil bacterial community， and the relative abundance of Proteobacteria and Bacteroidetes was increased， while the relative abundance of Acidobacteria was decreased. SOC， UE， and TP were important factors affecting the composition of bacterial communities. ③ The dominant phyla of soil fungi were Ascomycetes， Basidiomycetes， and Mortieromycetes. The relative abundance of Ascomycetes and Mortierella was increased. DHA， AP， and UE were important factors affecting the composition of the fungal community. ④ Different fertilization measures increased the complexity of the soil bacterial community network and decreased the complexity of the soil fungal community network. ⑤ FAPROTAX bacterial function prediction results showed that different fertilization measures improved soil carbon and nitrogen cycling-related functions. FUNGuild fungal function prediction showed that returning straw to field could inhibit the growth of soil pathogens， while applying organic fertilizer could promote the growth of saprophytic fungi. Different fertilization measures could improve soil fertility and extracellular enzyme activity， increase the abundance of beneficial bacteria， significantly change the structure and composition of the soil microbial community， and promote soil carbon and nitrogen cycling. Straw returning to field could inhibit the growth of soil pathogens. The effects of organic and inorganic combined application （NPKS and NPKM） were better than those of NPK and OM. Organic and inorganic combined application was conducive to improving soil quality， promoting carbon and nitrogen cycling， and increasing crop yield， so as to achieve sustainable development of dry farming.

Straw return is a crucial agricultural practice for enhancing soil carbon accumulation and fertility， but it may induce nutrient limitation on soil microbes， potentially affecting CO₂ emissions. Phosphorus （P）， a key nutrient， plays an essential role in this context， yet how P availability and straw return regulate the CO₂ emissions of black soil remains poorly understood. We utilized soil samples from a long-term fertilization experiment in Gongzhuling black soil under a non-fertilized treatment. Nine gradients of P addition （0， 5， 10， 15， 30， 50， 80， 100， and 150 mg·kg^-1 Na₂HPO₄ solution， on a P basis）， combined with straw addition， were carried out in a 28-day incubation experiment， during which their dynamic CO₂ emissions were monitored to examine the effects of P and straw addition on CO₂ emissions from the soil to identify the driving factors. The results indicated that in the absence of straw addition， the cumulative CO₂ emissions from the tested black soil ranged from 311.0 to 386.5 mg·kg^-1 （on a carbon basis）. As P addition rates increased， the cumulative CO₂ emissions exhibited a nonlinear pattern， initially decreasing and then increasing， with the lowest value occurring at 15 mg·kg^-1 P addition rate， which was 18.1% lower than that in the no-phosphorus treatment. Under straw addition， the cumulative CO₂ emissions from the tested black soil ranged from 721.9 to 855.5 mg·kg^-1， which was on average 2.3 times higher than those in the absence of straw. As P addition increased， the CO₂ emissions showed a linear increase， peaking at 100 mg·kg^-1 P addition rate， which was 18.5% higher than that in the no-phosphorus treatment. Correlation analysis revealed that， in the absence of straw， cumulative CO₂ emissions were significantly positively correlated with dissolved organic carbon （DOC） and dissolved inorganic nitrogen （DIN）. Under straw addition， cumulative CO₂ emissions were significantly positively correlated with DOC， DIN， and microbial biomass carbon （MBC）. P addition significantly altered the contents of DOC， DIN， MBC， and metabolic quotient （qCO₂）， thereby regulating CO₂ emissions. In conclusion， in the absence of straw， moderate P addition can alleviate carbon decomposition loss in the tested black soil. However， with straw addition， P addition might promote carbon decomposition， increasing CO₂ emissions from the tested black soil. In practical agricultural production， applying phosphate fertilizer should be rationally regulated based on soil P availability to avoid excessive application， thereby achieving the dual objectives of carbon sequestration and CO₂ emission reduction.

With the construction industry's continuous progress in high-quality development and ecological resilience enhancement， the coupling and coordination between these two dimensions have emerged as a critical issue for achieving sustainable development. Leveraging panel data from 30 Chinese provinces spanning 2014 to 2023， this study employs an integrated methodology combining the weighting-TOPSIS approach， a coupling coordination degree model， kernel density estimation， the Dagum Gini coefficient， and Markov chain analysis to systematically investigate the spatiotemporal coupling characteristics and regional disparities in the high-quality development of the construction industry and ecological resilience. The results indicate that： ①During the study period， the coupling coordination degree between high-quality development and ecological resilience exhibited an overall upward trend， albeit with significant regional heterogeneity. ②The eastern region demonstrated the highest level of coupling coordination， coupled with the most rapid growth rate， while the northeastern region experienced pronounced growth fluctuations. In contrast， the central and western regions lagged behind the national average in terms of growth. ③Intra-regional disparities gradually narrowed， whereas inter-regional differences remained a persistent challenge for the coupling coordination of the two systems. ④The coupling coordination degree displayed a tendency to maintain its existing state， with spatial proximity effects playing a significant role in enhancing coordination levels. This study advances the theoretical understanding of the coupling coordination mechanism between high-quality development and ecological resilience in the construction sector， offering strategic insights and policy recommendations for fostering regional coordinated development and sustainable transformation.

The impact of land use change on habitat quality is of great significance for advancing regional ecological civilization construction. In this study， Jiangxi Province， a national ecological civilization pilot zone， was selected as the study area. Land use data from 2000， 2010， and 2020 were used to analyze the characteristics of land use changes. Three representative scenarios from CMIP6， namely SSP119， SSP245， and SSP585， were adopted to simulate the patterns of land use change in 2040 and 2060 using the SD-PLUS model. Subsequently， the variations of habitat quality were assessed using the InVEST model. The results showed that： ① Between 2000 and 2020， land use change in Jiangxi Province exhibited a pattern of "rapid at first， then slowing down，" with land conversion rate in the first decade being 4.67 times that in the second decade. The primary transitions included mutual conversions among paddy field， dryland， forested land， and sparse forest land， as well as the transfer to urban land and other construction land. ② During this period， the mean habitat quality decreased by 3.57%， with medium， good， and excellent quality levels predominating. In contrast， poor and relatively poor levels were primarily concentrated in urban built-up areas and exhibited a "large-character" diffusion pattern along major transportation corridors. ③ Future scenarios indicated a continued reduction in cultivated land and an expansion of construction land. Under SSP119， forest land was significantly increased， resulting in the highest habitat quality. Under SSP245， a more balanced land-use pattern was observed， with moderate habitat quality. Under SSP585， the most pronounced expansion of construction land occurred， leading to the lowest habitat quality. ④ The improvement in habitat quality was primarily driven by the increase in forested land and sparse forest land. Conversely， the expansion of construction land and the conversion of forest land to cultivated land were the main factors contributing to the decline in habitat quality. These findings provide a scientific basis for ecological governance and sustainable development in Jiangxi Province.

The seasonal fluctuations in water levels significantly influence the wet-dry transitions in the water-level-fluctuating zone （WLFZ） of lakes. Bacteria， as an important microbial group in the biogeochemical cycles of this zone， profoundly affect the ecological functions of the area. A thorough investigation of the changes in soil bacterial communities during water level fluctuations is crucial for understanding the ecological functions of the WLFZ and its responses to environmental changes. Using high-throughput sequencing technology， the seasonal variation of bacterial communities in the Poyang Lake WLFZ from 2019 to 2020 was systematically analyzed. The results indicated that Proteobacteria， Acidobacteriota， and Chloroflexi were the dominant phyla in the WLFZ， while Actinobacteriota， Firmicutes， and Bacteroidota exhibited significant differences between submerged and exposed states. During flooding， bacterial diversity significantly decreased， and the influence of stochastic processes on community assembly increased. Additionally， bacterial co-occurrence networks under flooded conditions displayed higher complexity， modularity， and keystone species abundance. In exposed states， bacterial diversity correlated significantly positively with soil moisture content （P<0.01）， with TN and TP identified as primary drivers of community composition. Under flooded conditions， NH₄⁺-N， TN， TP， and TOC were significantly correlated with bacterial diversity （P<0.01）， while soil pH and TOC were the key factors affecting community structure. The predicted functions of the bacterial community such as nitrogen fixation， carbohydrate degradation， aromatic compound degradation， and methane metabolism exhibited distinct seasonal shifts driven by water-level fluctuations. These findings enhance our understanding of how soil bacterial communities in lake WLFZ adapt structurally and functionally to seasonal hydrological changes.

To construct an ecological security pattern for Henan Province to support regional ecological protection and sustainable development， a comprehensive analysis of the landscape elements in Henan Province was conducted using morphological spatial pattern analysis （MSPA）， circuit theory， and space syntax. By identifying key elements such as ecological sources， corridors， pinch points， and obstacles and evaluating the morphological structure characteristics of the ecological network， critical spaces requiring priority restoration were determined. The results indicated that： ① The total area of landscape types in Henan Province was 32 066 km²， accounting for 19.20% of the study area， with core areas covering 23 095 km²， or 13.83%. When the area threshold was ≥3 km²， 380 ecological sources were identified， occupying 12.96% of the total study area， mainly concentrated in the western， central， and southern regions. ② Based on circuit theory， 1 139 ecological corridors were extracted， with a total length of 18 206.68 km， including 504 important， 403 secondary important， and 232 general corridors. Additionally， 316 ecological pinch points （located at the junctions of corridors and sources） and 290 ecological obstacles （distributed along corridors） were identified. ③ It is recommended to prioritize the restoration of 109 ecological obstacles in the northern and eastern regions， with a total restoration area of 1 387.19 km². ④ Ultimately， an ecological security pattern of "one belt， two verticals， three screens， four corridors， and multiple nodes" was constructed. This pattern and its key elements fully reflect the actual characteristics of Henan Province's ecosystem， and the proposed restoration strategies provide scientific basis and practical guidance for regional ecological protection and sustainable development.

A comprehensive assessment of regional ecosystem health （EH） and exploring its driving mechanisms are crucial for the sustainable development of human societies. Both service supply-demand and environmental quality significantly impact EH， and the failure to integrate them into the EH evaluation framework limits the rationality and comprehensiveness of the results. Therefore， this study proposed an improved EH assessment framework （VORSDR_EEQ） and assessed the spatial and temporal changes in EH from 2001 to 2020 using a new framework that integrates ecosystem organization structure， service supply-demand， and environmental quality with Guizhou Province as the study area. It also investigated the driving mechanisms of EH by combining Geodetector and the multi-scale geographically weighted regression model. The results showed that： ① Compared with the existing EH assessment frameworks， the VORSDR_EEQ framework can simultaneously reflect the coercive effects of dryness and heat of the regional natural environment and the impacts of ecosystem service supply and demand-gain-loss relationships on EH， thereby providing more realistic evaluation results. ② Overall， EH in Guizhou Province showed an improving trend， although the degradation in the eastern regions was more severe. ③ The dominant driver factors of EH shifted from natural factors to human activities. Among these， the influence of soil moisture gradually decreased， the influence of human footprint continued to increase and exceeded that of soil moisture， and the influence of afforestation projects was no longer significant by 2020. At the same time the interaction between natural factors and human activities maintained a high level of influence on EH. ④ There were significant spatiotemporal variations in the mechanism of action of different drivers on EH， and targeted ecological management strategies should be formulated in conjunction with the actual situation of EH response to natural and human activities when promoting ecological engineering and economic development. The findings provide a scientific basis for ecological restoration and conservation in Guizhou Province and offer new insights for EH assessment and management in other regions.

To elucidate the deceleration trend in PM_2.5 concentration reduction and its formation mechanisms， this study analyzed PM_2.5 concentration variations in Qingdao from 2013 to 2023， combined with factors such as air pollutants， meteorology， and emissions. A phased interpretable machine learning model was applied to predict the variations of PM_2.5， investigate the formation mechanisms， and identify key drivers under evolving environmental policies. The results showed that PM_2.5 concentration decreased from （56.3±43.66） μg·m^-3 in 2013 to （30.2±24.50） μg·m^-3 in 2023 in Qingdao， with a reduction of approximately 46.3%， primarily driven by the reduction in secondary aerosols. Notably， the fastest decline of PM_2.5 occurred before 2017 at a rate of -4.33 μg·（m³·a）^-1， mainly due to reduced formation of secondary sulfate from the end-of-pipe control in the industrial and power sectors. After 2017， the deceleration in the decline of PM_2.5 concentrations stemmed from asynchronous reductions in sulfate， nitrate， and ammonium precursors， leading to enhanced secondary PM_2.5 formation. The machine learning model indicated the enhanced sensitivity of PM_2.5 to NO₂ under low SO₂ conditions， with the contribution of NO₂ to PM_2.5 concentrations increasing by approximately 6%， while that of SO₂ became negligible. Additionally， meteorological factor contribution to PM_2.5 concentrations increased by 5.1%. PM_2.5 concentrations exhibited a seasonal variation in the order of winter > spring > autumn > summer. Influenced by increased primary emissions from the residential sector， winter PM_2.5 concentrations showed the slowest decline over the years. Therefore， controlling residential sources can reduce primary PM_2.5 emissions， and a coordinated multi-pollutant emission control strategy can effectively reduce secondary PM_2.5 formation.

There are sparse reports on the vertical distribution characteristics of microplastics in drinking water sources with large water depths. To elucidate the vertical distribution characteristics of microplastics in the water of Miyun Reservoir， an important surface drinking water source in Beijing， a sampling campaign was conducted for surface， intermediate， and bottom water at different sites in both the flood and non-flood seasons. The abundance， morphology， and compositional characteristics of microplastics were investigated， and the spatial and temporal heterogeneity of microplastics was analyzed. The results showed that the abundance of microplastics in the water of Miyun Reservoir ranged from 0.4 to 7.6 n·L^-1， with an average abundance of （2.7±1.6） n·L^-1. The average abundance of microplastics in the Chaohe River reservoir area was higher than that in the Baihe River reservoir area. At the Baihe River inlet， microplastic abundance in the intermediate and bottom water layers was significantly higher than that in the surface water layer， whereas the Chaohe River inlet exhibited the highest abundance in the surface layer. Microplastic abundance was significantly higher during the flood season. Microplastic particles in the non-flood season were larger， more colorful， and comprised higher proportions of fibers and debris than those in the flood season. Vertically， fibers dominated all water layers， aggregating mainly in the surface and bottom water layers during flood season but were homogeneously distributed during the non-flood season. Microplastics smaller than 0.5 mm accumulated in the intermediate water during the flood season and migrated down to the bottom of the water column during the non-flood season. Polyethylene terephthalate （PET）， polyethylene （PE）， and polypropylene （PP） were the dominant microplastic types in Miyun Reservoir. PET mainly presented in the surface and bottom water layers， PE accumulated in the intermediate and bottom water layers， and PP clustered in the surface and intermediate water layers. The results of the ecological risk and exposure level assessment indicated that both the abundance risk level and exposure level of microplastics in Miyun Reservoir were low.