查看更多>>摘要：The excessive use of plastics in modern life has led to a significant increase in production and a correspondingrise in plastic waste generation. The slow degradation of plastics results in the introduction and accumulation ofmicroplastics (MP) in the environment, posing environmental and health risks. River networks, acting as conduitsbetween terrestrial and marine environments, play a crucial role in controlling the transport of MP. Predictingthe complex processes of MP pathways in these environments is an ongoing challenge. To address thisissue, we propose a model that integrates the advection-dispersion equation with anthropogenic MP loads andhydraulic river network characteristics. The validity of the model was assessed using literature data from threeriver networks worldwide. Model results show a good agreement between predictions and field observations(R~2 = 0.72). Consequently, predicted MP data was used to perform a potential pollution assessment through thepollution load index, revealing in most cases higher MP contamination in headwaters stream and a dilution effectalong the river network. The structure of the proposed model allows its further implementation to account forother transport mechanisms, interactions with other emerging contaminants (i.e., pharmaceuticals), and connectionswith other riverine environments, making it a valuable tool for understanding and mitigating MPpollution.
查看更多>>摘要：A closed Maar lake, receiving mostly atmospheric deposition, offers a unique setting for investigating the impactof human activities on the environment. In this study, we aimed to investigate the historical record of metals incore sediments of Maar Lake in Huguangyan (HGY), Southeast China, and elucidate the possible microbial responsesto anthropogenic metal stress. Five stages were divided according to the historical record of metals andcorresponding distribution of microbial community, among which Pb and Sn showed a peak value around 1760CE, indicating the ancient mining and smelting activities. Since the 1980s, a substantial enrichment of metalssuch as Zn, As, Mo, Cd, Sn, Sb, and Pb was observed, due to the rapid industrial growth in China. In terms ofmicroorganisms, Chloroflexi phylum, particularly dominated by Anaerolineales, showed significant correlationswith Pb and Sn, and could potentially serve as indicator species for mining and smelting-related contamination.Desulfarculales and Desulfobacterales were found to be more prevalent in recent period and exhibited positivecorrelations with anthropogenic metals. Moreover, according to the multivariate regression modeling and variance decomposition analysis, Pb and Sn could regulate Anaerolineales and further pose impact on the carboncycle; while sulfate-reducing bacteria (SRB) could response to anthropogenic metals and influence sulfur cycle.These findings provide new insights into the interaction between metals and microbial communities over humanhistory.
查看更多>>摘要：Oxidative stress is a prominent pathway for the health effects associated with fine particulate matter (PM_(2.5))exposure. Oxidative potential (OP) of PM has been associated to several health endpoints, but studies on itsimpact on biomarkers of oxidative stress remains insufficient. 300 pregnant women from the SEPAGES cohort(France) carried personal PM_(2.5) samplers for a week and OP was measured using ascorbic acid (AA) anddithiothreitol (DTT) assays, and normalized by 1) PM_(2.5) mass (Op_m) and 2) sampled air volume (Op_v). A pool ofthree urine spots collected on the 7th day of PM sampling was analyzed for biomarkers, namely 8-hydroxy-2-deoxyguanosine (8-OHdG), malondialdehyde (MDA) and 8-isoprostaglandin-F2α (8-isoPGF2α). Associationswere investigated using adjusted multiple linear regressions. OP effects were additionally investigated bystratifying by median PM_(2.5) concentration (14 μg m~(-3)). In the main models, no association was observed with 8-isoPGF2α, nor MDA. An interquartile range (IQR) increase in OP_m~(AA) exposure was associated with increased 8-OHdG (percent change: 6.2 %; 95 % CI: 0.2 % to 12.6 %). In the stratified analysis, exposure to OP_m~(AA) wasassociated with 8-OHdG for participants exposed to low levels of PM_(2.5) (percent change: 11.4 %; 95 % CI: 3.3 %to 20.1 %), but not for those exposed to high levels (percent change: - 1.0 %; 95 % CI: - 10.6 % to 9.6 %).Associations for OP_m~(DTT) also followed a similar pattern (p-values for OP_m~(AA)-PM and OP_m~(DTT)-PM interaction termswere 0.12 and 0.11, respectively). Overall, our findings suggest that OP_m~(AA) may be associated with increased DNAoxidative damage. This association was not observed with PM_(2.5) mass concentration exposure. The effects ofOP_m~(AA) in 8-OHdG tended to be stronger at lower (below median) vs. higher concentrations of PM_(2.5). Furtherepidemiological, toxicological and aerosol research are needed to further investigate the OP_m~(AA) effects on 8-OHdGand the potential modifying effect of PM mass concentration on this association.
查看更多>>摘要：Alpine meadow degradation, usually involving decreased soil nitrogen (N) and patchy landscapes, is a challengefor natural restoration. However, the mechanism underlying plant species coexistence under degradation isunclear. In this study, we evaluated plant N niche complementarity in degraded alpine meadows on the Qinghai–Tibet Plateau using a ~(15)N-labeling (~(15)NO_3~-, ~(15)NH_4~+, and ~(15)N-glycine) experiment. At the community level, theconcentration of ~(15)NO_3~- in the degraded alpine meadow was 1.5 times higher than that in the undegraded alpinemeadow; both alpine meadows had a significant preference for NO_3~- (60.72 % and 66.84 % for the degraded and undegraded alpine meadows, respectively), and the degree of glycine preference was significantly higher in thedegraded alpine meadow (30.77 %) relative to the undegraded alpine meadow (21.85 %). At the species level,dominant species in both alpine meadows consistently preferred NO_3~-; the generalist species that can be found inboth meadows and unique species of the two alpine meadows generally showed NO_3~- preferences, while the otherplant species that were unevenly distributed in the degraded alpine meadow tended to show increased utilizationof glycine, which could reduce N competition. We observed that differentiation among N sources and the unevendistribution of unique species may explain the stability of degraded alpine meadows. Our results suggested thatuneven distributions of plants could have strong impacts on community stability and highlighted the importanceof considering fine-scale analysis in studies of niche theory. This study has important implications for therestoration of degraded alpine meadows.
查看更多>>摘要：Vegetation, as a multi-type and multi-functional green energy, plays an important role in regional carbonemission reduction and carbon neutrality. This study carried out the concept of green and sustainable developmentin depth and constructed an emergy quantification methodology system for the multidimensional servicefunctions of vegetation ecosystems consisting of forests and grasslands based on the theory of emergy analysisand multidisciplinary integration methods. Using the theory of spatial correlation and breakpoints, we delineatedthe major ecological zones and investigated the radiation effects of typical regulating functions. Taking Luoyang,China, as an example, the results showed that the annual sequence of vegetation ecosystem service function(VES) emergy in Luoyang City showed a decreasing and then increasing trend with 2015 as the cut-off point.Early-stage Forest exploitation had profound effects, while increasing cultural benefits in later stages demonstratednational emphasis on forest research and conservation. The forest's high-quality ecological zone inLuoyang City could be found in the three southern counties of Luoning (LN), Luanchuan (LC), and Song (S). Theradiation effect encompassed the entire city, resulting in an obvious impact with a total radiation of approximately4.10E+20 sej. The high-quality ecological zone of the grassland did not appear until 2020 and is locatedin Yiyang (YY) county in central Luoyang. It benefited only the surrounding counties and had a total radiation of1.32E+18sej. However, the development trend is optimistic. The spatial pattern of vegetation should be suitablefor natural conditions, and the development strategy of localization as the driving force of the whole should be realized through the establishment of high-quality ecological zones, so as to promote harmonious coexistencebetween human and nature through green development.
查看更多>>摘要：Urban green spaces (UGS) are an effective mitigation strategy for urban heat islands (UHIs) through theirevapotranspiration and shading effects. Yet, the extent to which local UGS cooling effects vary across differentbackground climates, plant characteristics and urban settings across global cities is not well understood. Thisstudy analysed 265 local air temperature (T_A) measurements from 58 published studies across globallydistributed sites to infer the potential influence of background climate, plant and urban variables among differentUGS types (trees, grass, green roofs and walls). We show that trees were more effective at reducing local T_A, withreductions 2–3 times greater than grass and green roofs and walls. We use a hierarchical linear mixed effectsmodel to reveal that background climate (mean annual temperature) and plant characteristics (specific leaf areavegetation index) had the greatest influence on cooling effects across UGS types, while urban characteristics didnot significantly influence the cooling effects of UGS. Notably, trees dominated the overall local cooling effectsacross global cities, indicating that greater tree growth in mild climates with lower mean annual temperatureshas the greatest mitigation potential against UHIs. Our findings provide insights for urban heat mitigation usingUGS interventions, particularly trees across cities worldwide with diverse climatic and environmental conditionsand highlight the essential role of trees in creating healthy urban living environments for citizens under extremeweather conditions.
查看更多>>摘要：Understanding how vegetation (shrub) cover in drylands affects local-to-regional soil water dynamics andassociated water balances is of immense importance because of the abundance of afforestation projects worldwide.Vegetation's role in the control of soil water presents a particular challenge to soil water storage (SWS)management in the drylands of China. To address this knowledge gap, we conducted a two-year study in the MuUs Desert of northwest China. The study involved the acquisition of in-situ soil water measurements within thefirst 180 cm of soil at three sand dune sites characterized by their differences in % shrub cover. The sand dunesvaried from a vegetation-free, bare-ground sand dune site (BF) and two partly vegetated sites, one with mediumlevel(40 %) and another with high shrub cover (80 %; MF and HF, respectively). Results revealed that the sitewith the high shrub cover (HF) suffered a net reduction in soil water content (SWC) by up to 32.7 and 39.8 % inthe shallow and deep subsoil (0–100 and 100–180 cm), respectively, when compared to corresponding changesat the BF site. Soil water content was shown to be largely influenced by site properties, namely shrub biomassand litter density (p < 0.05). Due to aboveground vegetation and rainfall interception by the litter, 32.2 mm ofeffective rainfall was reduced to the soil for every 10 %-increase in shrub cover. Bands of soil water depletionduring the dry year did not fully recover during the following wet year, resulting in the development of a driedsoil layer with an average SWC of 4.6–7.8 %. Increased evapotranspiration (ETtotal) led to a decrease in SWS and relative extractable soil water (REW), which caused ETtotal at HF to be lower than the rate observed at MF. Thesefindings highlight the need for improvements in current restoration strategies, meant at striking a balance betweenvegetation restoration and SWC by developing optimal plant-community cover and mosaicked vegetationsystems.
查看更多>>摘要：Direct and indirect photolysis are important abiotic processes in aquatic environments through which plasticscan be transformed physically and chemically. Transport of biodegradable plastics in water is influenced byvertical mixing and turbulent flow, which make biodegradable plastics remain susceptible to sunlight andphotolysis despite their high density. In general, biodegradable plastics are composed of ester containingpolymers (e.g., poly(butylene succinate), polyhydroxyalkanoate, and polylactic acid), whereas nonbiodegradableplastics are composed of long chains of saturated aliphatic hydrocarbons in their backbones (e.g., polyethylene, polypropylene, and polystyrene). Based on the reviewed knowledge and discussion, we mayhypothesize that 1) direct photolysis is more pronounced for non-biodegradation than for biodegradable plastics,2) smaller plastics such as micro/nano-plastics are more prone to photodegradation and photo-transformation bydirect and indirect photolysis, 3) the production rate of reactive oxygen species (ROS) on the surface ofbiodegradable plastics is higher than that of non-biodegradable plastics, 4) the photodegradation of biodegradableplastics may be promoted by ROS produced from biodegradable plastics themselves, and 5) the subsequentreactions of ROS are more active on biodegradable plastics than non-biodegradable plastics. Moreover, micro/nanoplastics derived from biodegradable plastics serve as more effective carriers of organic pollutantsthan those from non-biodegradable plastics and thus biodegradable plastics may not necessarily be more ecofriendlythan non-biodegradable plastics. However, biodegradable plastics have been largely unexplored fromthe viewpoint of direct or indirect photolysis. Roles of reactive oxygen species originating from biodegradableplastics should be further explored for comprehensively understanding the photodegradation of biodegradableplastics.
查看更多>>摘要：Intrinsically floating microplastics (MP) such as polyethene (PE) or polypropylene (PP) are among the mostcommon MPs found in aquatic sediments. There must hence be mechanisms that cause lighter-than-water MPs todeposit despite them being buoyant. How these MPs end up in the sediment bed is only partly understood. Thisstudy explores how turbulence in the water can affect the vertical movement of buoyant MP and bring them incontact with the bed. The deposition of PE (995 kg m~(-3)) in slow-flowing water (average flow velocities of 1.85and 4.17 cm s~(-1)) was measured by tracking them and analyzing their motion in an open, rectangular, glass-sidedflume. Flow characteristics in terms of turbulent kinetic energy and shear velocity were measured by particleimage velocimetry. Experiments were conducted at a water depth of 27 cm and at various hydraulic conditionscreated by adjusting inflow speeds and using different bed materials: medium gravel, fine gravel, medium sand,cohesive sediment, and glass. The results showed that the vertical velocity of the MPs in the turbulent flowregimes varied over 4 orders of magnitude from their predicted rising velocity in quiescent water (laminar flow).Turbulence mixing resulted in distribution throughout the water column with a substantial quantity consistentlysubject to downward vertical transport, which in turn increased the chance of the PE particles encountering thebed and potentially getting immobilized. This work provides a plausible explanation and further experimental validation for the concept of mixing induced transfer of MPs from the water surface to the sediments of shallowwaters.
查看更多>>摘要：With respect to total emissions, the proportion of household carbon emissions exhibits an upward trend;therefore, to reduce carbon emissions and enhance energy efficiency, researchers should understand the reasonsfor the increase in household carbon emissions. This study, which is based on the construction of the “BroadbandChina” demonstration cities and the 2010–2018 China Family Panel Studies, applies a difference-in-differencesmethod. It identifies the impact of digital infrastructure construction on indirect household energy consumption,carbon emissions, and energy efficiency. The estimation results indicate that digital infrastructure constructionsignificantly enhances household energy consumption and carbon emissions, and that it enhances the householdenergy efficiency pertaining to household carbon emissions and usage. Furthermore, the results indicate thathouseholds mainly enhance energy usage and efficiency by increasing developmental consumption. Additionally,this study noted that digital infrastructure construction affects household energy consumption and efficiencythrough the development of the consumer Internet and industrial Internet, which reshapes household consumptionbehavior and promotes the producers' technological progress.
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