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Long-term thinning decreases the contribution of heterotrophic respiration to soil respiration in subalpine plantations

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Journal of Forestry Research 2024年第3期35卷 189-204页

作者： Longfei Chen Zhibin He Wenzhi Zhao Xi Zhu Qin Shen Mingdan Song Zhengpeng Li Junqia Kong Shuping Yang Yuan Gao Northwest Institute of Eco-Environment and Resources Chinese Academy of SciencesLanzhou 730000People's Republic of China State Forestry Administration Key Laboratory of Forest Resources and Environmental Management Beijing Forestry UniversityBeijing 100083People's Republic of China Academy of Agriculture and Forestry Sciences Qinghai UniversityXining 810000People's Republic of China College of Landscape Architecture Zhejiang A&F UniversityHangzhou 310000People's Republic of China

Interest in the dynamics of soil respiration(R_(S))in subalpine forest ecosystems is increasing due to their high soil carbon density and potential sensitivity to environmental changes.However,as a principal silvicultural practice,the long-term impacts of thinning on R_(S) and its heterotrophic and autotrophic respiration components(R_(h) and Ra,respectively)in subalpine plantations are poorly understood,espe-cially in winter.A 3-year field observation was carried out with consideration of winter CO_(2) efflux in middle-aged sub-alpine spruce plantations in northwestern China.A trench-ing method was used to explore the long-term impacts of thinning on R,Rn and Ra.Seventeen years after thinning,mean annual Rs,Rn and R_(a) increased,while the contribu-tion of R_(h) to R_(s) decreased with thinning intensity.Thinning significantly decreased winter R,because of the reduction in Rn but had no significant effect on Ra.The temperature sensitivity(Q_(10))of R_(h) and R_(a) also increased with thinning intensity,with lower Q_(10) values for R_(h)(2.1-2.6)than for Ra(2.4-2.8).The results revealed the explanatory variables and pathways related to Rn and R_(a) dynamics.Thinning increased soil moisture and nitrate nitrogen(NO_(3)^(-)-N),and the enhanced nitrogen and water availability promoted R_(h) and R_(a) by improving fine root biomass and microbial activity.Our results highlight the positive roles of NO_(3)^(-)-N in stimulating R_(s) components following long-term thinning.Therefore,applications of nitrogen fertilizer are not recommended while thinning subalpine spruce plantations from the perspective of reducing soil CO_(2) emissions.The increased Q_(10) values of R_(s) components indicate that a large increase in soil CO_(2) emissions would be expected following thinning because of more pronounced climate warming in alpineregions.

关键词： Heterotrophic respiration Autotrophic respiration Long-term thinning impacts Cold seasons Subalpine plantations temperature sensitivity

Compatibility evaluation between waterborne epoxy resin and SBR latex modified asphalt emulsion

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第1期11卷 160-171页

作者： Jianhua Yang Zhengqi Zhang Ying Fang Key Laboratory for Special Area Highway Engineering of Ministry of Education Chang'an UniversityXi'an 710064China

Good compatibility between waterborne epoxy resin(WER)modifier and styrene-butadiene rubber(SBR)latex modified asphalt emulsion(SBRE)is an essential premise for good pavement performance of WER and SBR latex compositely modified asphalt emulsion(WSAE).This study aims to explore the compatibility between WER modifier and SBRE.To achieve the goal,several WER modifiers produced by two methods were first selected to modify SBRE,thus the WSAEs were prepared.Next,storage stability and workability of the WSAEs themselves,and high-temperature performance,rheological behavior and temperature sensitivity of their evaporated residues were compared and evaluated via performing a series of experiments,respectively,thus the WER modifier possessing an optimal modification effect was recommended.Results show that the storage stability of WSAEs is sensitive to the amount of WERs.The incorporation of 1%WERs by the mass of SBRE improves the storage stability of SBRE,while WERs that exceed 1%weaken its storage stability.When the WERs reach 3%and 4%,the 5 d storage stability of prepared WSAEs will be beyond the limitation of specification.Incorporating WERs into SBRE negatively affects the workability of SBRE,and the workability of WSAEs is adversely influenced by the WERs content and the storage time.To ensure the construction,the WSAEs with 3%and 4%WERs should not be stored for more than 36 h and 48 h,respectively.The WERs effectively improve the high-temperature performance of SBRE residue,especially the 3%WERs.Besides,the WERs notably enhance the rheological property and thermal stability of SBRE residue.In contrast,the WER modifier produced by chemically modified method has a smaller adverse impact on the storage stability and workability of WSAE,and a larger enhancement on the high-temperature performance,rheological property and thermal stability of SBRE residue,which is thus recommended to modify SBRE.

关键词： Waterborne epoxy resin SBR modified asphalt emulsion Workability Rheological property temperature sensitivity Compatibility evaluation

Nucleoprotein phosphorylation site(Y385)mutation confers temperature sensitivity to influenza A virus due to impaired nucleoprotein oligomerization at a lower temperature

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Science China(Life Sciences) 2021年第4期64卷 633-643页

作者： Weinan Zheng Liang Cui Minghui Li Yun Li Wenhui Fan Limin Yang Jing Li Lei Sun Wenjun Liu CAS Key Laboralory of Pathogenic Microbiology and Immumology Institute of MicrobiologyChinese Academy of SciencesBejing 100101China University of Chinese Academy of Sciences Bejing 100101China State Key Laboratory for Conservation and Urilization of Subtropical Agro-Bioresourses&Laboratory of Animal Infectious Diseases College of Animal Sciences and Veterinary MedicineGuangxi UniversitNanning 530004China Instinute of Microbiology Center for Biosafety Mega-ScienceChinese Academy of SciencesBeijing 100101China

Mutations in viral proteins can lead to the cold adaption of influenza A virus and the cold-adapted virus is an important vaccination instrument.Here,we identify a novel strain of influenza A virus with cold sensitivity conferred by a mutation at a phosphorylation site within the nucleoprotein(NP).The highly conserved tyrosine 385 residue(Y385)of NP was identified as a phosphorylation site by mass spectrometry.The constructive NP phosphorylation mimicked by Y385 E mutation was fatal for virus replication,while the continuous Y385 dephosphorylation mimicked by Y385 F mutation had little impact on virus replication in vitro.Notably,the Y385 F virus showed much lower replicative capacity in turbinates of mice compared with the wild type virus.Moreover,the replication of Y385 F virus was significantly reduced in both A549 and MDCK cells grown at 33℃,when compared to that at 37℃.These results indicated that the Y385 F mutation led to cold sensitivity of virus.We further found that the cold sensitivity of Y385 F virus could be attributed to diminished NP oligomerization rather than any changes in intracellular localization.Taken together,these findings suggest that the phosphorylation of NP may be a critical factor that regulates the temperature sensitivity of influenza A virus.

关键词： influenza A virus nucleoprotein phosphorylation dephosphorylation temperature sensitivity

Effect of Polymer Matrix on temperature sensitivity of temperature Sensitive Paints

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Chinese Journal of Polymer Science 2015年第10期33卷 1351-1358页

作者： Zhi-dong Wang Xiao-zhong Qu 金毕青 Yi Shi 刘治田金熹高 School of Material Science and Engineering Wuhan Institute of Technology State Key Laboratory of Polymer Physics and Chemistry Institute of Chemistry Chinese Academy of Sciences University of Chinese Academy of Sciences

The thermal quenching behaviors of the temperature sensitivity paints （TSP） composed of europium（III） thenoyltrifluoroacetonate （EuTTA） and Eu-phenanthrene complex （Eu-2） in polystyrene （PS）, polymethylmethacrylate （PMMA） and epoxy resin （EP） were investigated. It is found that both the emission intensity and temperature sensitivity were not only affected by the luminescence probes, but also by the polymer matrix. The interaction between probes and matrix results in the alteration of both the non-radiation decay rate and the activation energy of the non-radiative process for the thermal quenching process, i.e. larger activation energy of the non-radiative process shows higher temperature sensitivity and less emission intensity. Therefore, it was confirmed that the temperature sensitivity and luminescent intensity of TSP depended not only on the luminescence probes but also on the polymer matrix.

关键词： temperature sensitive paints Europium complex Thermal quenching Polymer matrix temperature sensitivity

The effects of climate warming on microbe-mediated mechanisms of sediment carbon emission

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Journal of Environmental Sciences 2023年第7期129卷 16-29页

作者： Weiwei Lü Haoyu Ren Wanchang Ding He Li Xin Yao Xia Jiang College of Water Sciences Beijing Normal UniversityBeijing 100875China State Key Laboratory of Environmental Criteria and Risk Assessment National Engineering Laboratory of Lake Water Pollution Control and Ecological Restoration TechnologyChinese Research Academy of Environmental SciencesBeijing 100012China School of Environment and Planning University of LiaochengLiaocheng 252000China

Due to significant differences in biotic and abiotic properties of soils compared to those of sediments,the predicted underlying microbe-mediated mechanisms of soil carbon emissions in response to warming may not be applicable for estimating similar emissions from inlandwater sediments.We addressed this issue by incubating different types of sediments,(including lake,small river,and pond sediments)collected from 36 sites across the Yangtze River basin,under short-term experimentalwarming to explore the effects of climatewarming on sediment carbon emission and the underlying microbe-mediated mechanisms.Our results indicated that under climate warming Cc emissions were affected more than CH_(4) emissions,and that pond sediments may yield a greater relative contribution of CO_(2) to total carbon emissions than lake and river sediments.Warming-induced CO_(2) and CH_(4) increases involve different microbe-mediated mechanisms;Warming-induced sediment CO_(2) emissions were predicted to be directly positively driven by microbial community network modularity,which was significantly negatively affected by the quality and quantity of organic carbon and warming-induced variations in dissolved oxygen,Conversely,warminginduced sediment CH_(4) emissionswere predicted to be directly positively driven bymicrobial community network complexity,which was significantly negatively affected by warminginduced variations in pH.Our findings suggest that biotic and abiotic drivers for sediment CO_(2) and CH_(4) emissions in response to climate warming should be considered separately when predicting sediment organic carbon decomposition dynamics resulting from climate change.

关键词： Inland water sediments temperature sensitivity Carbon emission Microbe-mediated mechanism Short-term experimental warming

Laboratory investigation of coal sample permeability under the coupled effect of temperature and stress

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Frontiers of Earth Science 2022年第4期16卷 963-974页

作者： Yina YU Zhaoping MENG Jiangjiang LI Yixin LU Caixia GAO College of Geosciences and Surveying Engineering China University of Mining and Technology(Beijing)Beijing 100083China State Key Laboratory of Coal and CBM Co-mining Jincheng 048000China Exploration and Development Research Institute PetroChina Huabei Oilfield CompanyRenqiu 062552China

The stress and temperature sensitivities of coal reservoirs are critical geological factors affectingcoalbed methane(CBM)well exploitation;in particular it is important to reduce or eliminate their influence on coal reservoir permeability.To investigate coal permeability behavior at various effective stresses and temperatures,CH4 permeability tests were conducted on raw coal samples under a varying effective stress of 2.0-8.0 MPa under five different temperatures(25℃-65℃)in the laboratory.The results show that the permeability of the coal samples exponentially decreases with increasing effective stress or temperature,which indicates obvious stress and temperature sensitivity.Through a dimension-less treatment of coal permeability,effective stress,and temperature,a new stress sensitivity index S and tempera-ture index ST are proposed to evaluate coal stress and temperature sensitivity evaluation parameters.These new parameters exhibit integrality and uniqueness,and,in combination with stress sensitivity coefficient αk,tempe-rature sensitivity coefficient αT,and the permeability damage rate PDR,the sensitivities of coal permeability to stress and temperature are evaluated.The results indicate that coal sample stress sensitivity decreases with increasing effective stress,while it first decreases and then increases with increasing temperature.Additionally,coal sample temperature sensitivity shows a downward trend when temperature increases and fluctuates when effective stress increases.Finally,a coupled coal permeability model considering the impacts of effective stress and temperature is established,and the main factors affecting coal reservoir permeability and their control mechanism are explored.These results can provide some theoretical guidance for the further development of deep CBM.

关键词： deep coal reservoir permeability variation stress sensitivity temperature sensitivity

Spatial distribution and driving factors of sediment net nitrogen mineralization in riparian zone of the Three Gorges Reservoir

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Journal of Mountain Science 2023年第2期20卷 381-390页

作者： JIA Kai-tao HE Li-ping WANG Ke-hong YU Zhi-guo LIANG Li-jiao YU Zhuo-lin LIN Jun-jie Key Laboratory of Water Environment Evolution and Pollution Control in the Three Gorges Reservoir Chongqing Three Georges UniversityChongqing 404100China School of Hydrology and Water Resources Nanjing University of Information Science and TechnologyNanjing 210044China

Inorganic nitrogen(N)loss through sediment N mineralization is important for eutrophication surrounding riparian zone.Sediment physicochemical properties have been changed at water-level elevation in riparian zone of the Three Gorges Reservoir(TGR)due to differences in hydrological stress and human activity intensity.However,spatial distribution and driving factor of net N mineralization rate(Nmin)and its temperature sensitivity(Q10)based on the changes in sediment physicochemical properties are still unclear at waterlevel elevation in the riparian zone.A total of 132 sediment samples in the riparian zone were collected including 11 transections and 12 water-level elevations on basin scale of the TGR during drying period,to conduct a 28-day incubation at 15℃,22℃,29℃and 36℃.Nmin,total N(TN)and substrate quality(SQ)increased with water-level elevation,while Q10 showed an opposite trend(P<0.001).Results of the structural equation model showed that water-level elevation had direct positive effects on TN and SQ(P<0.01).In addition,TN was the major factor that had a direct positive effect on Nmin,and SQ was the crucial factor that had a direct negative effect on Q10(P<0.001).In conclusion,increases in TN and SQ were major driving factors of Nmin and its Q10 at water-level elevation,respectively,in riparian zone of the TGR during drying period.

关键词： Inorganic nitrogen loss Sediment physicochemical properties Drying period Substrate quality Net nitrogen mineralization rate temperature sensitivity

Soil microbial communities regulate the threshold effect of salinity stress on SOM decomposition in coastal salt marshes

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Fundamental Research 2023年第6期3卷 868-879页

作者： Guangliang Zhang Junhong Bai Jia Jia Wei Wang Dawei Wang Qingqing Zhao Chen Wang Guozhu Chen State Key Laboratory of Water Environment Simulation School of EnvironmentBeijing Normal UniversityBeijing 100875China Advanced Institute of Natural Sciences Beijing Normal UniversityZhuhai 519087China Henan Key Laboratory of Ecological Environment Protection and Restoration of Yellow River Basin Yellow River Institute of Hydraulic ResearchZhengzhou 450003China Shandong Provincial Key Laboratory of Applied Microbiology Ecology InstituteQilu University of Technology(Shandong Academy of Sciences)Ji'nan 250103China

Salinity stress is one of the critical environmental drivers of soil organic matter(SOM)decomposition in coastal ecosystems.Although the temperature sensitivity(Q_(10))of SOM decomposition has been widely applied in Earth system models to forecast carbon processes,the impact of salinity on SOM decomposition by restructuring microbial communities remains uncovered.Here,we conducted a microcosm experiment with soils collected from the coastal salt marsh in the Yellow River Estuary,which is subjected to strong dynamics of salinity due to both tidal flooding and drainage.By setting a gradient of salt solutions,soil salinity was adjusted to simulate salinity stress and soil carbon emission(CO_(2))rate was measured over the period.Results showed that as salinity increased,the estimated decomposition constants based on first-order kinetics gradually decreased at different temperatures.Below the 20‰salinity treatments,which doubled the soil salinity,Q_(10)increased with increasing salinity;but higher salinity constrained the temperature-related response of SOM decomposition by inhibiting microbial growth and carbon metabolisms.Soil bacteria were more sensitive to salinity stress than fungi,which can be inferred from the response of microbial beta-diversity to changing salinity.Among them,the phylotypes assigned to Gammaproteobacteria and Bacilli showed higher salt tolerance,whereas taxa affiliated with Alphaproteobacteria and Bacteroidota were more easily inhibited by the salinity stress.Several fungal taxa belonging to Ascomycota had higher adaptability to the stress.As the substrate was consumed with the incubation,bacterial competition intensified,but the fungal co-occurrence pattern changed weakly during decomposition.Collectively,these findings revealed the threshold effect of salinity on SOM decomposition in coastal salt marshes and emphasized that salt stress plays a key role in carbon sequestration by regulating microbial keystone taxa,metabolisms,and interactions.

关键词： Salt marshes Salinity stress Soil organic matter decomposition temperature sensitivity Threshold effect Microbial community

Thermal sensitivity of photonic crystal fibers in opto-electronic oscillators

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The Journal of China Universities of Posts and Telecommunications 2009年第4期16卷 1-6页

作者： Afshin S. Daryoush Deptartment of ECE Drexel University

Stable opto-electronic oscillators （OEOs） are realized using long fiber delay lines and changes in the index of refraction of high quality factor delay line results in temperature sensitivity of OEOs. temperature sensitivity of various OEOs is measured to compare index of refraction variation of standard （SMF-28） and photonic crystal fiber （PCF）. Both hollow-core （HC） and solid-core （SC） versions of PCF are quantified. SC-PCF exhibited a factor of three reductions in the rate of index of refraction change （about ＋4.7 ppm/℃） with temperature over SMF-28 （about 12 ppm/℃） based OEO. Although HC-PCF have a greater attenuation per unit length, but those fibers have demonstrated a negative rate of change （about - 0.6 ppm/℃） in the effective index of refraction with temperature and prospect of thermal stability in the OEO using passive techniques is great when a combination of HC-PCF and SMF-28 are employed as fiber delay lines.

关键词： opto-electronie oscillators frequency stability phase noise temperature sensitivity photonic crystal fiber hollow and solid core PCF