Graphitic carbon nitride(g-C3N4)exhibits great mechanical as well as thermal characteristics,making it a valuable ma-terial for use in photoelectric conversion devices,an accelerator for synthesis of organic compounds...Graphitic carbon nitride(g-C3N4)exhibits great mechanical as well as thermal characteristics,making it a valuable ma-terial for use in photoelectric conversion devices,an accelerator for synthesis of organic compounds,an electrolyte for fuel cell applications or power sources,and a hydrogen storage substance and a fluorescence detector.It is fabricated using dif-ferent methods,and there is a variety of morphologies and nanostructures such as zero to three dimensions that have been designed for different purposes.Ther e are many reports about g-C3N4 in recent years,but a comprehensive review which covers nanostructure dimensions and their properties are missing.This review paper aims to give basic and comprehensive understanding of the photocatalytic and electrocatalytic usages of g-C3N4.It highlights the recent progress of g-C3N4 nano-structure designing by covering synthesis methods,dimensions,morphologies,applications and properties.Along with the summary,we will also discuss the challenges and prospects.Scientists,investigators,and engineers looking at g-C3N4 nanostructures for a variety of applications might find our review paper to be a useful resource.展开更多
The use of visible-light responsive photocatalysts for removing heavy metal ions in wastewater has received great attention.However,the development of photocatalysts with high activity and recyclability remains a huge...The use of visible-light responsive photocatalysts for removing heavy metal ions in wastewater has received great attention.However,the development of photocatalysts with high activity and recyclability remains a huge challenge.Herein,a recyclable carbon fiber cloth-supported porous CdS nanorod photocatalyst was fabricated by a two-step hydrothermal treatment using AgVO_(3) nanowires as templates.The results indicated that under visible-light illumination,the carbon cloth-supported porous CdS nanorods showed improved photocatalytic activity for the reduction of Cr(Ⅵ),with an apparent rate constant exceeding that of carbon cloth-supported CdS nanospheres by a factor of 1.65 times.Moreover,the carbon cloth-supported porous CdS nanorods can be easily separated and be reused.This brings a new perspective for developing photocatalysts with high efficiency and recyclability for wastewater treatment.展开更多
Sacred forests play a valuable role in the conservation of local biodiversity and provide numerous ecosystem services in Cameroon. The aim of this study was to estimate floristic diversity, stand structures and carbon...Sacred forests play a valuable role in the conservation of local biodiversity and provide numerous ecosystem services in Cameroon. The aim of this study was to estimate floristic diversity, stand structures and carbon stocks in the sacred forests of Bandrefam and Batoufam (western Cameroon). The floristic inventory and the stand structures were carried out in 25 m × 25 m plots for individuals with diameters greater than 10 cm;5 m × 5 m for individuals with diameters less than 10 cm. Carbon stocks were estimated using the non-destructive method and allometric equations. The floristic inventory identified 65 species divided into 57 genera and 30 families in the Bandrefam sacred forest and 45 species divided into 42 genera and 27 families in the Batoufam sacred forest. In the Bandrefam, the most important families are Phyllanthaceae (53.98%), Moraceae (21.69%), Lamiaceae (20.15%). At Batoufam, the most important families are Phyllanthaceae (39.73%), Fabaceae (28.47%), Araliaceae (23.77%). Malacantha alnifolia (55.14%), Vitex grandifolia (18.43%), Bosqueia angolensis (15.06%) were the most important species in Bandrefam. Otherwise, Malacantha alnifolia (28%), Polyscias fulva (22.73%), Psychotria sp. (21.28%) were the most important in Batoufam. The Bandrefam sacred forest has the highest tree density (2669 stems/ha). Total carbon stock is 484.88 ± 2.28 tC/ha at Batoufam and 313.95 ± 0.93 tC/ha at Bandrefam. The economic value varies between 5858.04 ± 27.62 USD/ha in Batoufam sacred forest and 3788.51 ± 11.26 USD/ha in Bandrefam sacred forest. The number of individuals and small-diameter trees has little influence on the carbon stocks in the trees. Medium-diameter trees store the most carbon, and very large-diameter trees, which are very poorly represented, store less carbon. In another way, wood density and the basal areas influence the carbon storage of the trees.展开更多
Tibetan Plateau,as one of the most carbon intensive regions in China,is crucial in the carbon cycle,and accurately estimating its vegetation carbon density(C_(VEG))is essential for assessing regional and national carb...Tibetan Plateau,as one of the most carbon intensive regions in China,is crucial in the carbon cycle,and accurately estimating its vegetation carbon density(C_(VEG))is essential for assessing regional and national carbon balance.However,the spatial distribution of regional C_(VEG) is not available remains highly uncertain due to lack of systematic research,especially for different organs.Here,we investigated the spatial distribution patterns and driving factors of C_(VEG) among different plant organs(leaf,branch,trunk and root)by systematically field grid-sampling 2040 field-plots of plant communities over the Tibetan Plateau from 2019 to 2020.The results showed that the carbon content of plant organs ranged from 255.53 to 515.58 g kg^(-1),with the highest in branches and the lowest in roots.Among the different plant functional groups,the highest C_(VEG) was found in evergreen coniferous forests,and the lowest in desert grasslands,with an average C_(VEG) of 1603.98 g m^(-2).C_(VEG) increased spatially from northwest to southeast over the Tibetan Plateau,with MAP being the dominant factor.Furthermore,the total vegetation carbon stock on the Tibetan Plateau was estimated to be 1965.62 Tg for all vegetation types.Based on the comprehensive field survey dataset,the Random Forest model effectively predicted and mapped the spatial distribution of C_(VEG)(including aboveground,belowground,and the total biomass carbon density)over the Tibetan Plateau with notable accuracy(validation R2 values were 71%,56%,and 64%for C_(AGB),C_(BGB),and C_(VEG),respectively)at a spatial resolution of 1 km×1 km.Our findings can help improve the accuracy of regional carbon stock estimations and provide parameters for carbon cycle model optimization and remote sensing calibration in the future.展开更多
Although the application of straw decomposing microorganism inoculants(SDMI)can accelerate straw decomposition,the underlying mechanisms affecting soil organic carbon(SOC)under different scenarios remain unclear.We co...Although the application of straw decomposing microorganism inoculants(SDMI)can accelerate straw decomposition,the underlying mechanisms affecting soil organic carbon(SOC)under different scenarios remain unclear.We conducted a meta-analysis using 226 observations from 86 studies on SOC changes under straw return with or without SDMI applications.Overall,our results indicated that straw with SDMI application increased the SOC stock by 1.51%at an initial carbon-to-nitrogen ratio(ICNR)>25(P<0.05),while the effect of ICNR≤25was insignificant.In particular,at ICNR>25,application of SDMI-treated straw increased SOC stocks in northern temperate continental areas(NTC)higher than in subtropical monsoon regions(STM).Furthermore,the straw with SDMI application increased higher SOC stocks in soils with pH>7.5 than those with pH≤7.5.In terms of agricultural management practices,SOC stocks were significantly higher in straw buried(SB),the experimental duration of straw return(EDSR)≥1 year,the straw return amount(SRA)>6,000 kg ha^(–1),and the SDMI application rate(SDMIR)>30 kg ha^(–1)conditions.The effect of straw with SDMI on SOC stocks under straw burying(SB)was significantly higher than that under straw mulching(SM)at ICNR≤25.At ICNR>25,EDSR,SDMIR,and the mean annual precipitation(MAP)were the main drivers of the effect of SDMI addition to straw on SOC stocks.Straw with SDMI induced SOC stock increases which increased with EDSR and decreased with increasing MAP.These findings provide a scientific basis for decision-makers and stakeholders to improve soil C management via the application of SDMI-amended straw at both regional and large scales.展开更多
Collaborative forest management (CFM) is a form of forest governance in which local communities are involved in the management and decision-making processes related to forest resources. It is believed that forests und...Collaborative forest management (CFM) is a form of forest governance in which local communities are involved in the management and decision-making processes related to forest resources. It is believed that forests under such management are better in tree diversity and conservation status and thus hold more carbon stocks. The study assessed the impact of CFM on carbon stocks, tree species diversity & tree species density in Mabira Central Forest Reserve. Data were collected from plots that were systematically laid in the different purposively selected forest areas. The study findings show that there is no difference in stem density and carbon stocks between CFM and non-CFM areas. CFM areas had lower species richness compared to non-CFM areas. CFM areas, however, exhibited more species diversity than non-CFM areas. Climax colonization may favor a few dominant species over others, hence lowering species diversity despite the number of species being many in the understory, hence at the same time increasing species richness. Likewise, disturbance in CFM area may affect natural colonization and favor the emergency of many species either naturally or through assisted regeneration by reforestation, hence increasing diversity, whereas artificial selection of preferred species through harvesting may lower species richness, as observed. Recommendations for improving collaborative forest management (CFM) areas include implementing targeted interventions to enhance carbon sequestration, such as promoting reforestation and afforestation with high-carbon-storing species and strengthening monitoring and evaluation frameworks to assess carbon stock changes over time. Additionally, efforts should focus on enhancing biodiversity conservation by implementing more stringent protection measures and reducing human disturbance while encouraging community participation in biodiversity monitoring and conservation education.展开更多
To achieve the target of carbon neutrality,it is crucial to develop an efficient and green synthesis methodology with good atomic economy to achieve sufficient utilization of energy and sustainable development.Photoin...To achieve the target of carbon neutrality,it is crucial to develop an efficient and green synthesis methodology with good atomic economy to achieve sufficient utilization of energy and sustainable development.Photoinduced electron transfer reversible addition-fragmentation chain-transfer(PET-RAFT)polymerization is a precise methodology for constructing polymers with well-defined structures.However,conventional semiconductor-mediated PET-RAFT polymerization still has considerable limitations in terms of efficiency as well as the polymerization environment.Herein,sulfur-doped carbonized polymer dots(CPDs)were hydrothermally synthesized for catalysis of aqueous PET-RAFT polymerization at unprecedented efficiency with a highest propagation rate of 5.05 h-1.The resulting polymers have well-controlled molecular weight and narrow molecular weight dispersion(Ð<1.10).Based on the optoelectronic characterizations,we obtained insights into the photoinduced electron transfer process and proposed the mechanism for CPD-mediated PET-RAFT polymerization.In addition,as-synthesized CPDs for PET-RAFT polymerization were also demonstrated to be suitable for a wide range of light sources(blue/green/solar irradiation),numerous monomers,low catalyst loading(low as 0.01 mg mL^(-1)),and multiple polar solvent environments,all of which allowed to achieve efficiencies much higher than those of existing semiconductor-mediated methods.Finally,the CPDs were confirmed to be non-cytotoxic and catalyzed PET-RAFT polymerization successfully in cell culture media,indicating broad prospects in biomedical fields.展开更多
Crop straw incorporation is widely recommended to maintain crop yields and improve soil organic carbon(SOC)stocks as well as soil quality.However,the long-term effects of different straw incorporation practices on the...Crop straw incorporation is widely recommended to maintain crop yields and improve soil organic carbon(SOC)stocks as well as soil quality.However,the long-term effects of different straw incorporation practices on the SOC stock remain uncertain.In this study,a long-term experiment(2007 to 2018)with four treatments(MW_0:maize–wheat rotation with no straw incorporation,MW_(50):maize–wheat rotation with 50%chopped straw incorporation,MW_(b50):maize–wheat rotation with 50%in situ burned harvested straw,and MF_(50):maize–fallow rotation with 50%harvested maize straw incorporation)was set up to evaluate the response of the SOC stock to different straw incorporation methods.The results showed that the SOC stock significantly increased by 32.4,12.2 and 17.4%under the MW_(50),MW_(b50)and MF_(50)treatments,respectively,after continuous straw incorporation over a decade,while the SOC stock under MW0 was significantly reduced by 22.9%after the 11 year long-term experiment.Compared to MW_0,straw incorporation significantly increased organic carbon input,and improved the soil aggregate structure and the ratio of dissolved organic carbon(DOC)to particulate organic carbon(POC),but it did not significantly stimulate soil heterotrophic respiration,resulting in the increased SOC accumulation rate and SOC stocks of bulk soil.The increased ratio of DOC to microbial biomass carbon(MBC)enhanced the relative abundances of Acidobacteria and Proteobacteria but inhibited Bacteroidetes and Chloroflexi,and the bacterial relative abundances were the main reasons for the non-significant increase or even decrease in soil heterotrophic respiration with straw incorporation.The SOC stock would reach an equilibrium based on the results of Rothamsted carbon(RothC)model simulations,with a long-term equilibrium value of 18.85 Mg ha^(–1)under MW_(50).Overall,the results of the long-term field experiment(2007–2018)and RothC model simulation suggested that maize–wheat rotation with 50%chopped straw incorporation delivered the largest benefits for the SOC stock in calcareous soils of subtropical mountain landscapes over the long term.展开更多
In view of the volume instability of steel slag aggregate leading to the quality problem of expansion damage in asphalt road construction,the 4.75-9.5 mm steel slag particles were treated by autoclaved carbonation tec...In view of the volume instability of steel slag aggregate leading to the quality problem of expansion damage in asphalt road construction,the 4.75-9.5 mm steel slag particles were treated by autoclaved carbonation technology,and the effects of the carbonation system(temperature and time)on the autoclaved pulverization rate,f-CaO content,and the relationship between them for the carbonated steel slag were investigated.In addition,the microstructure of the carbonated steel slag was analyzed by X-ray diffractometer(XRD),scanning electron microscope and energy dispersive spectrometer(SEM-EDS),metallographic microscope and X-ray fluorescence imaging spectrometer(XRF).The experimental results indicate that,under the initial CO_(2)pressure of 1.0 MPa,increasing the carbonation temperature leads to the increase in the crystal plane spacing of Ca(OH)_(2)that was generated by the hydration of minerals in steel slag,and promotes the transformation of carbonated CaCO_(3)from the orthorhombic system to the hexagonal system,resulting in the increase of the crystal planes spacing of them,meantime,accelerates the decomposition of RO phases and also the outward migration of Ca^(2+),Fe^(2+),and Mn^(2+)ions to cover and coat on the Si^(4+),Al^(3+)ions,and impels the formation of hydroxides such as Fe(OH)_(3)and the formation of carbonates such as Ca(Mg)CO_(3),FeCO_(3)and MnCO_(3).Carbonation at the temperature of 90℃for 3 h can reach the center of 4.75-9.5 mm steel slag particles.Meanwhile,the increase of temperature can promote the mineral reaction in steel slag,resulting in the fuzzy interface between mineral phases,increase of burrs,dispersion,crossover,reduction of grain size,and rearrangement of mineral particles.展开更多
Over the past few decades,photocatalysis technology has received extensive attention because of its potential to mitigate or solve energy and environmental pollution problems.Designing novel materials with outstanding...Over the past few decades,photocatalysis technology has received extensive attention because of its potential to mitigate or solve energy and environmental pollution problems.Designing novel materials with outstanding photocatalytic activities has become a research hotspot in this field.In this study,we prepared a series of photocatalysts in which BiOCl nanosheets were modified with carbon quantum dots(CQDs)to form CQDs/BiOCl composites by using a simple solvothermal method.The photocatalytic performance of the resulting CQDs/BiOCl composite photocatalysts was assessed by rhodamine B and tetracycline degradation under visible-light irradiation.Compared with bare BiOCl,the photocatalytic activity of the CQDs/BiOCl composites was significantly enhanced,and the 5 wt%CQDs/BiOCl composite exhibited the highest photocatalytic activity with a degradation efficiency of 94.5%after 30 min of irradiation.Moreover,photocatalytic N_(2)reduction performance was significantly improved after introducing CQDs.The 5 wt%CQDs/BiOCl composite displayed the highest photocatalytic N_(2)reduction performance to yield NH_3(346.25μmol/(g h)),which is significantly higher than those of 3 wt%CQDs/BiOCl(256.04μmol/(g h)),7 wt%CQDs/BiOCl(254.07μmol/(g h)),and bare BiOCl(240.19μmol/(g h)).Our systematic characterizations revealed that the key role of CQDs in improving photocatalytic performance is due to their increased light harvesting capacity,remarkable electron transfer ability,and higher photocatalytic activity sites.展开更多
The synergistic reaction of photocatalysis and advanced oxidation is a valid strategy for the degradation of harmful antibiotic wastewater.Herein,carbon dots(CDs)modified MIL-101(Fe)octahedrons to form CDs/MIL-101(Fe)...The synergistic reaction of photocatalysis and advanced oxidation is a valid strategy for the degradation of harmful antibiotic wastewater.Herein,carbon dots(CDs)modified MIL-101(Fe)octahedrons to form CDs/MIL-101(Fe)composite photocatalyst was synthesized for visible light-driven photocatalytic/persulfate(PS)-activated tetracycline(TC)degradation.The electron spin resonance(ESR)spectra,scavenging experiment and electrochemical analysis were carried out to reveal that the high visible light-driven photocatalytic degradation activity of TC over CDs/MIL-101(Fe)photocatalysts is not only ascribed to the production of free active radicals in the CDs/MIL-101(Fe)/PS system(·OH,·SO_(4-),^(1)O_(2),h^(+)and·O_(2)^(-))but also attributed to the consumption of electrons caused by the PS,which can suppress the recombination of photo-generated carriers as well as strong light scattering and electron trapping effects of CDs.Finally,the possible degradation pathways were proposed by analyzing intermediates via liquid chromatography-mass spectrometry technique.This research presents a rational design conception to construct a CDs/PS-based photocatalysis/advanced oxidation technology with high-efficient degradation activity for the remediation of organic antibiotic pollutant wastewater and for the improvement of carrier transport kinetics of photocatalysts.展开更多
Accurate estimations of biomass and its temporal dynamics are crucial for monitoring the carbon cycle in forest ecosystems and assessing forest carbon sequestration potentials.Recent studies have shown that integratin...Accurate estimations of biomass and its temporal dynamics are crucial for monitoring the carbon cycle in forest ecosystems and assessing forest carbon sequestration potentials.Recent studies have shown that integrating process-based models(PBMs)with remote sensing data can enhance simulations from stand to regional scales,significantly improving the ability to simulate forest growth and carbon stock dynamics.However,the utilization of PBMs for large-scale simulation of larch carbon storage distribution is still limited.In this study,we applied the parameterized 3-PG(Physiological Principles Predicting Growth)model across the Mengjiagang Forest Farm(MFF)to make broad-scale predictions of the biomass and carbon stocks of Larix olgensis plantation.The model was used to simulate average diameter at breast height(DBH)and total biomass,which were later validated with a wide range of observation data including sample plot data,forest management inventory data,and airborne laser scanning data.The results showed that the 3-PG model had relatively high accuracy for predicting both DBH and total biomass at stand and regional scale,with determination coefficients ranging from 0.78 to 0.88.Based on the estimation of total biomass,we successfully produced a carbon stock map of the Larix olgensis plantation in MFF with a spatial resolution of 20 m,which helps with relevant management advice.These findings indicate that the integration of 3-PG model and remote sensing data can well predict the biomass and carbon stock at regional and even larger scales.In addition,this integration facilitates the evaluation of forest carbon sequestration capacity and the development of forest management plans.展开更多
Savannas constitute a mixture of trees and shrub patches with a more continuous herbaceous understory.The contribution of this biome to the soil organic carbon(SOC)and above-ground biomass(AGB)carbon(C)stock globally ...Savannas constitute a mixture of trees and shrub patches with a more continuous herbaceous understory.The contribution of this biome to the soil organic carbon(SOC)and above-ground biomass(AGB)carbon(C)stock globally is significant.However,they are frequently subjected to land use changes,promoting increases in CO_(2) emissions.In Uruguay,subtropical wooded savannas cover around 100,000 ha,of which approximately 28%is circumscribed to sodic soils(i.e.,subtropical halophytic wooded savannas).Nevertheless,there is little background about the contribution of each ecosystem component to the C stock as well as site-specific allometric equations.The study was conducted in 5 ha of subtropical halophytic wooded savannas of the national protected area Esteros y Algarrobales del Rio Uruguay.This work aimed to estimate the contribution of the main ecosystem components(e.g.,soil,trees,shrubs,and herbaceous plants)to the C stock.Site-specific allometric equations for the most frequent tree species and shrub genus were fitted based on basal diameter(BD)and total height(H).The fitted equations accounted for between 77%and 98%of the aerial biomass variance of Netuma affinis and Vachellia caven.For shrubs(Baccharis sp.),the adjusted equation accounted for 86%of total aerial biomass.C stock for the entire system was 116.71±11.07 Mg·ha^(-1),of which 90.7%was allocated in the soil,8.3%in the trees,0.8%in the herbaceous plants,and 0.2%in the shrubs.These results highlight the importance of subtropical halophytic wooded savannas as C sinks and their relevance in the mitigation of global warming under a climate change scenario.展开更多
Photocatalysis has emerged as a promising alternative for converting and utilizing CO_(2).Polymeric carbon nitride(PCN),typically synthesized through the one-step thermal polycondensation of nitrogen-rich precursors,h...Photocatalysis has emerged as a promising alternative for converting and utilizing CO_(2).Polymeric carbon nitride(PCN),typically synthesized through the one-step thermal polycondensation of nitrogen-rich precursors,has shown considerable promise due to its adjustable band structure and inherent safety.Over the past five years,significant literature in this field has identified five primary methods for modifying PCN:morphology modulation,element doping,defect induction,co-catalyst loading,and heterojunction construction.A detailed discussion on how each modification method influences light absorption,charge separation,and surface reaction efficiencies in photocatalysis is provided.Based on these findings,several future directions for the development of PCN-based materials are proposed,such as designing tailored PCN structures for specific photocatalytic reactions and using theoretical calculations to verify and correct results from current characterization methods.Despite the challenges associated with the large-scale synthesis of PCN materials with controllable structures and satisfactory performance,this work offers valuable insights for advancing photocatalytic PCN-based systems for large-scale solar fuel production.展开更多
Biodiversity,large trees,and environmental conditions such as climate and soil have important effects on forest carbon stocks.However,recent studies in temperate forests suggest that the relative importance of these f...Biodiversity,large trees,and environmental conditions such as climate and soil have important effects on forest carbon stocks.However,recent studies in temperate forests suggest that the relative importance of these factors depends on tree mycorrhizal associations,whereby large-tree effects may be driven by ectomycorrhizal(EM)trees,diversity effects may be driven by arbuscular mycorrhizal(AM)trees,and environment effects may depend on differential climate and soil preferences of AM and EM trees.To test this hypothesis,we used forest-inventory data consisting of over 80,000 trees from 631 temperate-forest plots(30 m×30 m)across Northeast China to examine how biodiversity(species diversity and ecological uniqueness),large trees(top 1%of tree diameters),and environmental factors(climate and soil nutrients)differently regulate aboveground carbon stocks of AM trees,EM trees,and AM and EM trees combined(i.e.total aboveground carbon stock).We found that large trees had a positive effect on both AM and EM tree carbon stocks.However,biodiversity and environmental factors had opposite effects on AM vs.EM tree carbon stocks.Specifically,the two components of biodiversity had positive effects on AM tree carbon stocks,but negative effects on EM tree carbon stocks.Environmental heterogeneity(mean annual temperature and soil nutrients)also exhibited contrasting effects on AM and EM tree carbon stocks.Consequently,for the total carbon stock,the positive large-tree effect far surpasses the diversity and environment effect.This is mainly because when integrating AM and EM tree carbon stock into total carbon stock,the opposite diversity-effect(also environment-effect)on AM vs.EM tree carbon stock counteracts each other while the consistent positive large-tree effect on AM and EM tree carbon stock is amplified.In summary,this study emphasized a mycorrhizal viewpoint to better understand the determinants of overarching aboveground carbon profile across regional forests.展开更多
The ecosystems in Southern Ocean(SO)are undergoing significant changes in the context of climate change.To identify environment-phytoplankton feedbacks in SO,seawater samples were collected in the Cosmonaut Sea(CS)dur...The ecosystems in Southern Ocean(SO)are undergoing significant changes in the context of climate change.To identify environment-phytoplankton feedbacks in SO,seawater samples were collected in the Cosmonaut Sea(CS)during the 37 th China Antarctic Research Expedition(Jan.2021)(CHINARE-37)and subjected to analysis of particulate organic carbon(POC)and phytoplankton pigments.The remote sensing data,CHEMTAX community compositional modeling analysis,and physicochemical measurements were combined to explore the spatial variation of phytoplankton crops,taxonomic composition,and their environmental drivers.Historical phytoplankton community data from the area were also compared against those of this study to investigate inter-annual community differences and their potential causes.The column-integrated POC and chlorophyll-a(Chl-a)concentrations were 12.0±4.9 g/m^(2) and 73.8±50.5 mg/m^(2),respectively.The two most dominant taxa were haptophyte that are adapted to high Fe availability(Hapt-HiFe,mainly Phaeocystis antarctica)and Diatoms-A(Phaeodactylum tricornutum)that contributed to 33%±25%and 24%±14%to the total phytoplankton crops,respectively.Through cluster analysis,the study area was divided into two regions dominated by Hapt-HiFe and Diatoms-A,respectively.Spatially,Hapt-HiFe was mainly concentrated in the southwest coastal area that featured low temperatures,low salinity,and shallow euphotic zones.The coastal region southwest of the southern boundary of the Antarctic circumpolar current was experiencing a bloom of Hapt-HiFe during the study period that significantly contributed to the POC pool and Chl-a concentrations(R=0.46,P<0.01;R=0.42,P<0.01).Besides,the dominance of Hapt-HiFe in the CS suggests a high biological availability of dissolved Fe that is primarily associated with inputs from sea ice melt and upwellings.展开更多
Differences in forest attributes and carbon sequestration of each organ and layer between broadleaved and conifer forests of central and outer urban areas are not well-defined,hindering the precise management of urban...Differences in forest attributes and carbon sequestration of each organ and layer between broadleaved and conifer forests of central and outer urban areas are not well-defined,hindering the precise management of urban forests and improvement of function.To clarify the effect of two forest types with different urbanization intensities,we determined differences in vegetation composition and diversity,structural traits,and carbon stocks of 152 plots(20 m×20 m)in urban park forests in Changchun,which had the largest green quantity and carbon density effectiveness.We found that 1.1-fold thicker and healthier trees,and 1.6-to 2.0-fold higher,healthier,denser,and more various shrubs but with sparser trees and herbs occurred in the central urban forests(p<0.05)than in the outer forests.The conifer forests exhibited 30–70%obviously higher tree aboveground carbon sequestration(including stem and leaf)and 20%bigger trees,especially in the outer forests(p<0.05).In contrast,1.1-to 1.5-fold higher branch stocks,healthier and more diverse trees were found in broadleaved forests of both the inner and outer forests(p<0.05).Plant size and dominant species had similarly important roles in carbon stock improvement,especially big-sized woody plants and Pinus tabuliformis.In addition,a higher number of deciduous or needle species positively affected the broadleaved forest of the central urban area and conifer forest of the outer urban area,respectively.These findings can be used to guide precise management and accelerate the improvement of urban carbon function in Northeast China in the future.展开更多
Soil organic carbon(SOC)affects the function of terrestrial ecosystem and plays a vital role in global carbon cycle.Yet,large uncertainty still existed regarding the changes in SOC stock and quality with forest succes...Soil organic carbon(SOC)affects the function of terrestrial ecosystem and plays a vital role in global carbon cycle.Yet,large uncertainty still existed regarding the changes in SOC stock and quality with forest succession.Here,the stock and quality of SOC at 1-m soil profile were investigated across a subalpine forest series,including shrub,deciduous broad-leaved forest,broadleaf-conifer mixed forest,middle-age coniferous forest and mature coniferous forest,which located at southeast of Tibetan Plateau.The results showed that SOC stock ranged from 9.8 to29.9 kg·m^(-2),and exhibited a hump-shaped response pattern across the forest successional series.The highest and lowest SOC stock was observed in the mixed forest and shrub forest,respectively.The SOC stock had no significant relationships with soil temperature and litter stock,but was positively correlated with wood debris stock.Meanwhile,the average percentages of polysaccharides,lignins,aromatics and aliphatics based on FTIR spectroscopy were 79.89%,0.94%,18.87%and 0.29%,respectively.Furthermore,the percentage of polysaccharides exhibited an increasing pattern across the forest successional series except for the sudden decreasing in the mixed forest,while the proportions of lignins,aromatics and aliphatics exhibited a decreasing pattern across the forest successional series except for the sudden increasing in the mixed forest.Consequently,the humification indices(HIs)were highest in the mixed forest compared to the other four successional stages,which means that the SOC quality in mixed forest was worse than other successional stages.In addition,the SOC stock,recalcitrant fractions and HIs decreased with increasing soil depth,while the polysaccharides exhibited an increasing pattern.These findings demonstrate that the mixed forest had higher SOC stock and worse SOC quality than other successional stages.The high proportion of SOC stock(66%at depth of 20-100 cm)and better SOC quality(lower HIs)indicate that deep soil have tremendous potential to store SOC and needs more attention under global chan ge.展开更多
基金M Tahir is funded by EU H2020 Marie Skłodows-ka-Curie Fellowship(1439425).
文摘Graphitic carbon nitride(g-C3N4)exhibits great mechanical as well as thermal characteristics,making it a valuable ma-terial for use in photoelectric conversion devices,an accelerator for synthesis of organic compounds,an electrolyte for fuel cell applications or power sources,and a hydrogen storage substance and a fluorescence detector.It is fabricated using dif-ferent methods,and there is a variety of morphologies and nanostructures such as zero to three dimensions that have been designed for different purposes.Ther e are many reports about g-C3N4 in recent years,but a comprehensive review which covers nanostructure dimensions and their properties are missing.This review paper aims to give basic and comprehensive understanding of the photocatalytic and electrocatalytic usages of g-C3N4.It highlights the recent progress of g-C3N4 nano-structure designing by covering synthesis methods,dimensions,morphologies,applications and properties.Along with the summary,we will also discuss the challenges and prospects.Scientists,investigators,and engineers looking at g-C3N4 nanostructures for a variety of applications might find our review paper to be a useful resource.
文摘The use of visible-light responsive photocatalysts for removing heavy metal ions in wastewater has received great attention.However,the development of photocatalysts with high activity and recyclability remains a huge challenge.Herein,a recyclable carbon fiber cloth-supported porous CdS nanorod photocatalyst was fabricated by a two-step hydrothermal treatment using AgVO_(3) nanowires as templates.The results indicated that under visible-light illumination,the carbon cloth-supported porous CdS nanorods showed improved photocatalytic activity for the reduction of Cr(Ⅵ),with an apparent rate constant exceeding that of carbon cloth-supported CdS nanospheres by a factor of 1.65 times.Moreover,the carbon cloth-supported porous CdS nanorods can be easily separated and be reused.This brings a new perspective for developing photocatalysts with high efficiency and recyclability for wastewater treatment.
文摘Sacred forests play a valuable role in the conservation of local biodiversity and provide numerous ecosystem services in Cameroon. The aim of this study was to estimate floristic diversity, stand structures and carbon stocks in the sacred forests of Bandrefam and Batoufam (western Cameroon). The floristic inventory and the stand structures were carried out in 25 m × 25 m plots for individuals with diameters greater than 10 cm;5 m × 5 m for individuals with diameters less than 10 cm. Carbon stocks were estimated using the non-destructive method and allometric equations. The floristic inventory identified 65 species divided into 57 genera and 30 families in the Bandrefam sacred forest and 45 species divided into 42 genera and 27 families in the Batoufam sacred forest. In the Bandrefam, the most important families are Phyllanthaceae (53.98%), Moraceae (21.69%), Lamiaceae (20.15%). At Batoufam, the most important families are Phyllanthaceae (39.73%), Fabaceae (28.47%), Araliaceae (23.77%). Malacantha alnifolia (55.14%), Vitex grandifolia (18.43%), Bosqueia angolensis (15.06%) were the most important species in Bandrefam. Otherwise, Malacantha alnifolia (28%), Polyscias fulva (22.73%), Psychotria sp. (21.28%) were the most important in Batoufam. The Bandrefam sacred forest has the highest tree density (2669 stems/ha). Total carbon stock is 484.88 ± 2.28 tC/ha at Batoufam and 313.95 ± 0.93 tC/ha at Bandrefam. The economic value varies between 5858.04 ± 27.62 USD/ha in Batoufam sacred forest and 3788.51 ± 11.26 USD/ha in Bandrefam sacred forest. The number of individuals and small-diameter trees has little influence on the carbon stocks in the trees. Medium-diameter trees store the most carbon, and very large-diameter trees, which are very poorly represented, store less carbon. In another way, wood density and the basal areas influence the carbon storage of the trees.
基金supported by CAS Project for Young Scientists in Basic Research(YSBR-037)the National Natural Science Foundation of China(42141004,32430067)by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP,2019QZKK060602).
文摘Tibetan Plateau,as one of the most carbon intensive regions in China,is crucial in the carbon cycle,and accurately estimating its vegetation carbon density(C_(VEG))is essential for assessing regional and national carbon balance.However,the spatial distribution of regional C_(VEG) is not available remains highly uncertain due to lack of systematic research,especially for different organs.Here,we investigated the spatial distribution patterns and driving factors of C_(VEG) among different plant organs(leaf,branch,trunk and root)by systematically field grid-sampling 2040 field-plots of plant communities over the Tibetan Plateau from 2019 to 2020.The results showed that the carbon content of plant organs ranged from 255.53 to 515.58 g kg^(-1),with the highest in branches and the lowest in roots.Among the different plant functional groups,the highest C_(VEG) was found in evergreen coniferous forests,and the lowest in desert grasslands,with an average C_(VEG) of 1603.98 g m^(-2).C_(VEG) increased spatially from northwest to southeast over the Tibetan Plateau,with MAP being the dominant factor.Furthermore,the total vegetation carbon stock on the Tibetan Plateau was estimated to be 1965.62 Tg for all vegetation types.Based on the comprehensive field survey dataset,the Random Forest model effectively predicted and mapped the spatial distribution of C_(VEG)(including aboveground,belowground,and the total biomass carbon density)over the Tibetan Plateau with notable accuracy(validation R2 values were 71%,56%,and 64%for C_(AGB),C_(BGB),and C_(VEG),respectively)at a spatial resolution of 1 km×1 km.Our findings can help improve the accuracy of regional carbon stock estimations and provide parameters for carbon cycle model optimization and remote sensing calibration in the future.
基金supported by the Key Science and Technology Project of Anhui Province,China(2023n06020056)the National Natural Science Foundation of China(32071628)the Colleges and Universities Science Foundation of Anhui Province,China(2024AH020002)。
文摘Although the application of straw decomposing microorganism inoculants(SDMI)can accelerate straw decomposition,the underlying mechanisms affecting soil organic carbon(SOC)under different scenarios remain unclear.We conducted a meta-analysis using 226 observations from 86 studies on SOC changes under straw return with or without SDMI applications.Overall,our results indicated that straw with SDMI application increased the SOC stock by 1.51%at an initial carbon-to-nitrogen ratio(ICNR)>25(P<0.05),while the effect of ICNR≤25was insignificant.In particular,at ICNR>25,application of SDMI-treated straw increased SOC stocks in northern temperate continental areas(NTC)higher than in subtropical monsoon regions(STM).Furthermore,the straw with SDMI application increased higher SOC stocks in soils with pH>7.5 than those with pH≤7.5.In terms of agricultural management practices,SOC stocks were significantly higher in straw buried(SB),the experimental duration of straw return(EDSR)≥1 year,the straw return amount(SRA)>6,000 kg ha^(–1),and the SDMI application rate(SDMIR)>30 kg ha^(–1)conditions.The effect of straw with SDMI on SOC stocks under straw burying(SB)was significantly higher than that under straw mulching(SM)at ICNR≤25.At ICNR>25,EDSR,SDMIR,and the mean annual precipitation(MAP)were the main drivers of the effect of SDMI addition to straw on SOC stocks.Straw with SDMI induced SOC stock increases which increased with EDSR and decreased with increasing MAP.These findings provide a scientific basis for decision-makers and stakeholders to improve soil C management via the application of SDMI-amended straw at both regional and large scales.
文摘Collaborative forest management (CFM) is a form of forest governance in which local communities are involved in the management and decision-making processes related to forest resources. It is believed that forests under such management are better in tree diversity and conservation status and thus hold more carbon stocks. The study assessed the impact of CFM on carbon stocks, tree species diversity & tree species density in Mabira Central Forest Reserve. Data were collected from plots that were systematically laid in the different purposively selected forest areas. The study findings show that there is no difference in stem density and carbon stocks between CFM and non-CFM areas. CFM areas had lower species richness compared to non-CFM areas. CFM areas, however, exhibited more species diversity than non-CFM areas. Climax colonization may favor a few dominant species over others, hence lowering species diversity despite the number of species being many in the understory, hence at the same time increasing species richness. Likewise, disturbance in CFM area may affect natural colonization and favor the emergency of many species either naturally or through assisted regeneration by reforestation, hence increasing diversity, whereas artificial selection of preferred species through harvesting may lower species richness, as observed. Recommendations for improving collaborative forest management (CFM) areas include implementing targeted interventions to enhance carbon sequestration, such as promoting reforestation and afforestation with high-carbon-storing species and strengthening monitoring and evaluation frameworks to assess carbon stock changes over time. Additionally, efforts should focus on enhancing biodiversity conservation by implementing more stringent protection measures and reducing human disturbance while encouraging community participation in biodiversity monitoring and conservation education.
基金supported by the National Natural Science Foundation of China(NSFC)under Grant No.22035001 and No.52233005.
文摘To achieve the target of carbon neutrality,it is crucial to develop an efficient and green synthesis methodology with good atomic economy to achieve sufficient utilization of energy and sustainable development.Photoinduced electron transfer reversible addition-fragmentation chain-transfer(PET-RAFT)polymerization is a precise methodology for constructing polymers with well-defined structures.However,conventional semiconductor-mediated PET-RAFT polymerization still has considerable limitations in terms of efficiency as well as the polymerization environment.Herein,sulfur-doped carbonized polymer dots(CPDs)were hydrothermally synthesized for catalysis of aqueous PET-RAFT polymerization at unprecedented efficiency with a highest propagation rate of 5.05 h-1.The resulting polymers have well-controlled molecular weight and narrow molecular weight dispersion(Ð<1.10).Based on the optoelectronic characterizations,we obtained insights into the photoinduced electron transfer process and proposed the mechanism for CPD-mediated PET-RAFT polymerization.In addition,as-synthesized CPDs for PET-RAFT polymerization were also demonstrated to be suitable for a wide range of light sources(blue/green/solar irradiation),numerous monomers,low catalyst loading(low as 0.01 mg mL^(-1)),and multiple polar solvent environments,all of which allowed to achieve efficiencies much higher than those of existing semiconductor-mediated methods.Finally,the CPDs were confirmed to be non-cytotoxic and catalyzed PET-RAFT polymerization successfully in cell culture media,indicating broad prospects in biomedical fields.
基金financially supported by the National Key Research and Development Program of China(2023YFD1901200)the National Natural Science Foundation of China(U22A20562)+4 种基金the Sichuan Science and Technology Program,China(2022YFS0500)the Project of Special Research Assistant of the Chinese Academy of Sciences(Jing Zheng)the China Postdoctoral Science Foundation(2022M723079)the Sichuan Provincial Postdoctoral Research Foundation,China(TB2022042)the Science and Technology Research Program of Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(IMHEZYTS-08)。
文摘Crop straw incorporation is widely recommended to maintain crop yields and improve soil organic carbon(SOC)stocks as well as soil quality.However,the long-term effects of different straw incorporation practices on the SOC stock remain uncertain.In this study,a long-term experiment(2007 to 2018)with four treatments(MW_0:maize–wheat rotation with no straw incorporation,MW_(50):maize–wheat rotation with 50%chopped straw incorporation,MW_(b50):maize–wheat rotation with 50%in situ burned harvested straw,and MF_(50):maize–fallow rotation with 50%harvested maize straw incorporation)was set up to evaluate the response of the SOC stock to different straw incorporation methods.The results showed that the SOC stock significantly increased by 32.4,12.2 and 17.4%under the MW_(50),MW_(b50)and MF_(50)treatments,respectively,after continuous straw incorporation over a decade,while the SOC stock under MW0 was significantly reduced by 22.9%after the 11 year long-term experiment.Compared to MW_0,straw incorporation significantly increased organic carbon input,and improved the soil aggregate structure and the ratio of dissolved organic carbon(DOC)to particulate organic carbon(POC),but it did not significantly stimulate soil heterotrophic respiration,resulting in the increased SOC accumulation rate and SOC stocks of bulk soil.The increased ratio of DOC to microbial biomass carbon(MBC)enhanced the relative abundances of Acidobacteria and Proteobacteria but inhibited Bacteroidetes and Chloroflexi,and the bacterial relative abundances were the main reasons for the non-significant increase or even decrease in soil heterotrophic respiration with straw incorporation.The SOC stock would reach an equilibrium based on the results of Rothamsted carbon(RothC)model simulations,with a long-term equilibrium value of 18.85 Mg ha^(–1)under MW_(50).Overall,the results of the long-term field experiment(2007–2018)and RothC model simulation suggested that maize–wheat rotation with 50%chopped straw incorporation delivered the largest benefits for the SOC stock in calcareous soils of subtropical mountain landscapes over the long term.
基金Funded by the Natural Science Foundation of Hebei Province(No.E2020209010)the Science and Technology Plan Project of Tangshan(No.19150225E)the Key R&D Projects of North China University of Science and Technology(No.ZD-ST-202301)。
文摘In view of the volume instability of steel slag aggregate leading to the quality problem of expansion damage in asphalt road construction,the 4.75-9.5 mm steel slag particles were treated by autoclaved carbonation technology,and the effects of the carbonation system(temperature and time)on the autoclaved pulverization rate,f-CaO content,and the relationship between them for the carbonated steel slag were investigated.In addition,the microstructure of the carbonated steel slag was analyzed by X-ray diffractometer(XRD),scanning electron microscope and energy dispersive spectrometer(SEM-EDS),metallographic microscope and X-ray fluorescence imaging spectrometer(XRF).The experimental results indicate that,under the initial CO_(2)pressure of 1.0 MPa,increasing the carbonation temperature leads to the increase in the crystal plane spacing of Ca(OH)_(2)that was generated by the hydration of minerals in steel slag,and promotes the transformation of carbonated CaCO_(3)from the orthorhombic system to the hexagonal system,resulting in the increase of the crystal planes spacing of them,meantime,accelerates the decomposition of RO phases and also the outward migration of Ca^(2+),Fe^(2+),and Mn^(2+)ions to cover and coat on the Si^(4+),Al^(3+)ions,and impels the formation of hydroxides such as Fe(OH)_(3)and the formation of carbonates such as Ca(Mg)CO_(3),FeCO_(3)and MnCO_(3).Carbonation at the temperature of 90℃for 3 h can reach the center of 4.75-9.5 mm steel slag particles.Meanwhile,the increase of temperature can promote the mineral reaction in steel slag,resulting in the fuzzy interface between mineral phases,increase of burrs,dispersion,crossover,reduction of grain size,and rearrangement of mineral particles.
基金financially suppor ted by Key Research and Development Project of Anhui Province(No.2023h11020002)Natural Science Research Project for Universities in Anhui Province(No.KJ2021ZD0006)+3 种基金Natural Science Foundation of Anhui Province(No.2208085MB21)Fundamental Research Funds for the Central Universities of China(No.PA2022GDSK0056)Anhui Laboratory of Molecule-Based Materials(No.fzj22009)National Natural Science Foundation of China(Nos.21725102,22205108)。
文摘Over the past few decades,photocatalysis technology has received extensive attention because of its potential to mitigate or solve energy and environmental pollution problems.Designing novel materials with outstanding photocatalytic activities has become a research hotspot in this field.In this study,we prepared a series of photocatalysts in which BiOCl nanosheets were modified with carbon quantum dots(CQDs)to form CQDs/BiOCl composites by using a simple solvothermal method.The photocatalytic performance of the resulting CQDs/BiOCl composite photocatalysts was assessed by rhodamine B and tetracycline degradation under visible-light irradiation.Compared with bare BiOCl,the photocatalytic activity of the CQDs/BiOCl composites was significantly enhanced,and the 5 wt%CQDs/BiOCl composite exhibited the highest photocatalytic activity with a degradation efficiency of 94.5%after 30 min of irradiation.Moreover,photocatalytic N_(2)reduction performance was significantly improved after introducing CQDs.The 5 wt%CQDs/BiOCl composite displayed the highest photocatalytic N_(2)reduction performance to yield NH_3(346.25μmol/(g h)),which is significantly higher than those of 3 wt%CQDs/BiOCl(256.04μmol/(g h)),7 wt%CQDs/BiOCl(254.07μmol/(g h)),and bare BiOCl(240.19μmol/(g h)).Our systematic characterizations revealed that the key role of CQDs in improving photocatalytic performance is due to their increased light harvesting capacity,remarkable electron transfer ability,and higher photocatalytic activity sites.
基金the funding support from the National Natural Science Foundation of China(21906072,22006057)the Natural Science Foundation of Jiangsu Province(BK20190982)“Doctor of Mass entrepreneurship and innovation”Project in Jiangsu Province。
文摘The synergistic reaction of photocatalysis and advanced oxidation is a valid strategy for the degradation of harmful antibiotic wastewater.Herein,carbon dots(CDs)modified MIL-101(Fe)octahedrons to form CDs/MIL-101(Fe)composite photocatalyst was synthesized for visible light-driven photocatalytic/persulfate(PS)-activated tetracycline(TC)degradation.The electron spin resonance(ESR)spectra,scavenging experiment and electrochemical analysis were carried out to reveal that the high visible light-driven photocatalytic degradation activity of TC over CDs/MIL-101(Fe)photocatalysts is not only ascribed to the production of free active radicals in the CDs/MIL-101(Fe)/PS system(·OH,·SO_(4-),^(1)O_(2),h^(+)and·O_(2)^(-))but also attributed to the consumption of electrons caused by the PS,which can suppress the recombination of photo-generated carriers as well as strong light scattering and electron trapping effects of CDs.Finally,the possible degradation pathways were proposed by analyzing intermediates via liquid chromatography-mass spectrometry technique.This research presents a rational design conception to construct a CDs/PS-based photocatalysis/advanced oxidation technology with high-efficient degradation activity for the remediation of organic antibiotic pollutant wastewater and for the improvement of carrier transport kinetics of photocatalysts.
基金funded by National Key Research and Development Program(2023YFD220080430&2017YFD0600404)。
文摘Accurate estimations of biomass and its temporal dynamics are crucial for monitoring the carbon cycle in forest ecosystems and assessing forest carbon sequestration potentials.Recent studies have shown that integrating process-based models(PBMs)with remote sensing data can enhance simulations from stand to regional scales,significantly improving the ability to simulate forest growth and carbon stock dynamics.However,the utilization of PBMs for large-scale simulation of larch carbon storage distribution is still limited.In this study,we applied the parameterized 3-PG(Physiological Principles Predicting Growth)model across the Mengjiagang Forest Farm(MFF)to make broad-scale predictions of the biomass and carbon stocks of Larix olgensis plantation.The model was used to simulate average diameter at breast height(DBH)and total biomass,which were later validated with a wide range of observation data including sample plot data,forest management inventory data,and airborne laser scanning data.The results showed that the 3-PG model had relatively high accuracy for predicting both DBH and total biomass at stand and regional scale,with determination coefficients ranging from 0.78 to 0.88.Based on the estimation of total biomass,we successfully produced a carbon stock map of the Larix olgensis plantation in MFF with a spatial resolution of 20 m,which helps with relevant management advice.These findings indicate that the integration of 3-PG model and remote sensing data can well predict the biomass and carbon stock at regional and even larger scales.In addition,this integration facilitates the evaluation of forest carbon sequestration capacity and the development of forest management plans.
基金funded by the Comision Sectorial de Investigacion Cientifica(CSIC)[ID-501]the Agencia Nacional de Investigacion e Innovacion(ANII)[POS_EXT_2023_1_174913]。
文摘Savannas constitute a mixture of trees and shrub patches with a more continuous herbaceous understory.The contribution of this biome to the soil organic carbon(SOC)and above-ground biomass(AGB)carbon(C)stock globally is significant.However,they are frequently subjected to land use changes,promoting increases in CO_(2) emissions.In Uruguay,subtropical wooded savannas cover around 100,000 ha,of which approximately 28%is circumscribed to sodic soils(i.e.,subtropical halophytic wooded savannas).Nevertheless,there is little background about the contribution of each ecosystem component to the C stock as well as site-specific allometric equations.The study was conducted in 5 ha of subtropical halophytic wooded savannas of the national protected area Esteros y Algarrobales del Rio Uruguay.This work aimed to estimate the contribution of the main ecosystem components(e.g.,soil,trees,shrubs,and herbaceous plants)to the C stock.Site-specific allometric equations for the most frequent tree species and shrub genus were fitted based on basal diameter(BD)and total height(H).The fitted equations accounted for between 77%and 98%of the aerial biomass variance of Netuma affinis and Vachellia caven.For shrubs(Baccharis sp.),the adjusted equation accounted for 86%of total aerial biomass.C stock for the entire system was 116.71±11.07 Mg·ha^(-1),of which 90.7%was allocated in the soil,8.3%in the trees,0.8%in the herbaceous plants,and 0.2%in the shrubs.These results highlight the importance of subtropical halophytic wooded savannas as C sinks and their relevance in the mitigation of global warming under a climate change scenario.
基金the National Natural Science Foundation of China(22209207)the National Key Research and Development Program of China(2022YFB4002400).
文摘Photocatalysis has emerged as a promising alternative for converting and utilizing CO_(2).Polymeric carbon nitride(PCN),typically synthesized through the one-step thermal polycondensation of nitrogen-rich precursors,has shown considerable promise due to its adjustable band structure and inherent safety.Over the past five years,significant literature in this field has identified five primary methods for modifying PCN:morphology modulation,element doping,defect induction,co-catalyst loading,and heterojunction construction.A detailed discussion on how each modification method influences light absorption,charge separation,and surface reaction efficiencies in photocatalysis is provided.Based on these findings,several future directions for the development of PCN-based materials are proposed,such as designing tailored PCN structures for specific photocatalytic reactions and using theoretical calculations to verify and correct results from current characterization methods.Despite the challenges associated with the large-scale synthesis of PCN materials with controllable structures and satisfactory performance,this work offers valuable insights for advancing photocatalytic PCN-based systems for large-scale solar fuel production.
基金supported by the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(Grant ZDBS-LY-DQC019)the National Key Research and Development Program of China(2023YFE0124300)+4 种基金the National Natural Science Foundation of China(32301344)Major Program of Institute of Applied EcologyChinese Academy of Sciences(IAEMP202201)supported by grants from the U.S.National Science Foundation(DEB 2240431)the Seeding Projects for Enabling Excellence and Distinction(SPEED)Program at Washington University in St.Louis。
文摘Biodiversity,large trees,and environmental conditions such as climate and soil have important effects on forest carbon stocks.However,recent studies in temperate forests suggest that the relative importance of these factors depends on tree mycorrhizal associations,whereby large-tree effects may be driven by ectomycorrhizal(EM)trees,diversity effects may be driven by arbuscular mycorrhizal(AM)trees,and environment effects may depend on differential climate and soil preferences of AM and EM trees.To test this hypothesis,we used forest-inventory data consisting of over 80,000 trees from 631 temperate-forest plots(30 m×30 m)across Northeast China to examine how biodiversity(species diversity and ecological uniqueness),large trees(top 1%of tree diameters),and environmental factors(climate and soil nutrients)differently regulate aboveground carbon stocks of AM trees,EM trees,and AM and EM trees combined(i.e.total aboveground carbon stock).We found that large trees had a positive effect on both AM and EM tree carbon stocks.However,biodiversity and environmental factors had opposite effects on AM vs.EM tree carbon stocks.Specifically,the two components of biodiversity had positive effects on AM tree carbon stocks,but negative effects on EM tree carbon stocks.Environmental heterogeneity(mean annual temperature and soil nutrients)also exhibited contrasting effects on AM and EM tree carbon stocks.Consequently,for the total carbon stock,the positive large-tree effect far surpasses the diversity and environment effect.This is mainly because when integrating AM and EM tree carbon stock into total carbon stock,the opposite diversity-effect(also environment-effect)on AM vs.EM tree carbon stock counteracts each other while the consistent positive large-tree effect on AM and EM tree carbon stock is amplified.In summary,this study emphasized a mycorrhizal viewpoint to better understand the determinants of overarching aboveground carbon profile across regional forests.
基金Supported by the China’s National Polar Special Program“Impact and Response of Antarctic Seas to Climate Change”(Nos.IRASCC 01-01-02,IRASCC 02-02)the Scientific Research Fund of the Second Institute of Oceanography(Nos.JG 2011,JG 2211,JG 2013,JG 1805)+1 种基金the National Natural Science Foundation of China(Nos.42276255,41976228,41976227)the International Cooperation Key Project of Ministry of Science and Technology(No.2022 YFE 0136500)。
文摘The ecosystems in Southern Ocean(SO)are undergoing significant changes in the context of climate change.To identify environment-phytoplankton feedbacks in SO,seawater samples were collected in the Cosmonaut Sea(CS)during the 37 th China Antarctic Research Expedition(Jan.2021)(CHINARE-37)and subjected to analysis of particulate organic carbon(POC)and phytoplankton pigments.The remote sensing data,CHEMTAX community compositional modeling analysis,and physicochemical measurements were combined to explore the spatial variation of phytoplankton crops,taxonomic composition,and their environmental drivers.Historical phytoplankton community data from the area were also compared against those of this study to investigate inter-annual community differences and their potential causes.The column-integrated POC and chlorophyll-a(Chl-a)concentrations were 12.0±4.9 g/m^(2) and 73.8±50.5 mg/m^(2),respectively.The two most dominant taxa were haptophyte that are adapted to high Fe availability(Hapt-HiFe,mainly Phaeocystis antarctica)and Diatoms-A(Phaeodactylum tricornutum)that contributed to 33%±25%and 24%±14%to the total phytoplankton crops,respectively.Through cluster analysis,the study area was divided into two regions dominated by Hapt-HiFe and Diatoms-A,respectively.Spatially,Hapt-HiFe was mainly concentrated in the southwest coastal area that featured low temperatures,low salinity,and shallow euphotic zones.The coastal region southwest of the southern boundary of the Antarctic circumpolar current was experiencing a bloom of Hapt-HiFe during the study period that significantly contributed to the POC pool and Chl-a concentrations(R=0.46,P<0.01;R=0.42,P<0.01).Besides,the dominance of Hapt-HiFe in the CS suggests a high biological availability of dissolved Fe that is primarily associated with inputs from sea ice melt and upwellings.
基金the Youth Growth Technology Project,Science and Technology Department of Jilin Province(20230508130RC)Bureau of Forestry and Landscaping of Changchun.
文摘Differences in forest attributes and carbon sequestration of each organ and layer between broadleaved and conifer forests of central and outer urban areas are not well-defined,hindering the precise management of urban forests and improvement of function.To clarify the effect of two forest types with different urbanization intensities,we determined differences in vegetation composition and diversity,structural traits,and carbon stocks of 152 plots(20 m×20 m)in urban park forests in Changchun,which had the largest green quantity and carbon density effectiveness.We found that 1.1-fold thicker and healthier trees,and 1.6-to 2.0-fold higher,healthier,denser,and more various shrubs but with sparser trees and herbs occurred in the central urban forests(p<0.05)than in the outer forests.The conifer forests exhibited 30–70%obviously higher tree aboveground carbon sequestration(including stem and leaf)and 20%bigger trees,especially in the outer forests(p<0.05).In contrast,1.1-to 1.5-fold higher branch stocks,healthier and more diverse trees were found in broadleaved forests of both the inner and outer forests(p<0.05).Plant size and dominant species had similarly important roles in carbon stock improvement,especially big-sized woody plants and Pinus tabuliformis.In addition,a higher number of deciduous or needle species positively affected the broadleaved forest of the central urban area and conifer forest of the outer urban area,respectively.These findings can be used to guide precise management and accelerate the improvement of urban carbon function in Northeast China in the future.
基金the financial support from the National Natural Science Foundation of China(Nos.32001139,32071554)。
文摘Soil organic carbon(SOC)affects the function of terrestrial ecosystem and plays a vital role in global carbon cycle.Yet,large uncertainty still existed regarding the changes in SOC stock and quality with forest succession.Here,the stock and quality of SOC at 1-m soil profile were investigated across a subalpine forest series,including shrub,deciduous broad-leaved forest,broadleaf-conifer mixed forest,middle-age coniferous forest and mature coniferous forest,which located at southeast of Tibetan Plateau.The results showed that SOC stock ranged from 9.8 to29.9 kg·m^(-2),and exhibited a hump-shaped response pattern across the forest successional series.The highest and lowest SOC stock was observed in the mixed forest and shrub forest,respectively.The SOC stock had no significant relationships with soil temperature and litter stock,but was positively correlated with wood debris stock.Meanwhile,the average percentages of polysaccharides,lignins,aromatics and aliphatics based on FTIR spectroscopy were 79.89%,0.94%,18.87%and 0.29%,respectively.Furthermore,the percentage of polysaccharides exhibited an increasing pattern across the forest successional series except for the sudden decreasing in the mixed forest,while the proportions of lignins,aromatics and aliphatics exhibited a decreasing pattern across the forest successional series except for the sudden increasing in the mixed forest.Consequently,the humification indices(HIs)were highest in the mixed forest compared to the other four successional stages,which means that the SOC quality in mixed forest was worse than other successional stages.In addition,the SOC stock,recalcitrant fractions and HIs decreased with increasing soil depth,while the polysaccharides exhibited an increasing pattern.These findings demonstrate that the mixed forest had higher SOC stock and worse SOC quality than other successional stages.The high proportion of SOC stock(66%at depth of 20-100 cm)and better SOC quality(lower HIs)indicate that deep soil have tremendous potential to store SOC and needs more attention under global chan ge.
