The Jiutai area is tectonically situated at the eastern segment of the Central Asian Orogenic Belt(CAOB) and is close to the North China Craton(NCC) to the south, serving as an ideal place to investigations of the clo...The Jiutai area is tectonically situated at the eastern segment of the Central Asian Orogenic Belt(CAOB) and is close to the North China Craton(NCC) to the south, serving as an ideal place to investigations of the closure of the PaleoAsian Ocean(PAO). Sandstone samples collected from the Yangjiagou Formation and the Lujiatun Formation in this area have been studied in detail in terms of petrology, geochronology and geochemistry. The maximum depositional time of the Yangjiagou and Lujiatun formations has been constrained to early Middle Triassic(ca. 245 Ma) and middle Late Triassic(ca. 219 Ma), respectively. The Yangjiagou Formation, with a major provenance of dissected island arcs, is dominantly composed of Phanerozoic sediments from Northeastern China(NE China) massifs. The Lujiatun Formation, with major sediments from active continental margins, has a relatively larger proportion of Precambrian sediments, in which the ~1.85 Ga and ~2.5 Ga sediments are typical of the crystalline basements of the NCC and NE China massifs, which were uplifted and eroded during the closure of the PAO. Besides, both formations show the enrichment in LREEs and the depletion in HREEs, the common Eu negative anomalies, and trace element contents similar to that of the upper continental crust. Based on the provenance analysis of these two formations, the final closure time of the PAO in this area is constrained as from the early Middle Triassic(ca. 245 Ma) to the middle Late Triassic(ca. 219 Ma).展开更多
The accurate three-dimensional wind field obtained from a Doppler lidar not only helps to comprehend the refined structure of complex airflow but also provides important and valuable solutions for many fields.However,...The accurate three-dimensional wind field obtained from a Doppler lidar not only helps to comprehend the refined structure of complex airflow but also provides important and valuable solutions for many fields.However,the underlying homogeneity assumption of the typical wind retrieval methods,such as Doppler Beam Swinging(DBS)and Velocity Azimuth Display(VAD)based on a single-lidar,will introduce the measurement uncertainty in complex terrain.In this paper,a new design of a wind measurement campaign involving seven lidars was carried out,which contained the three-lidar-based Virtual Tower(VT)using a time-space synchronization technique and four single-lidars with different elevation angles.This study investigates the performance of VT and VAD measurements under various conditions and evaluates the sensitivity of wind measurement uncertainty of VAD to the horizontal spatial-and probe volume-average effects associated with elevation angles of the laser beam.The inter-comparison results between VT and four VADs show consistent trends with small relative errors under neutral atmospheric conditions with weak wind velocity.Under convective or high Turbulence Intensity(TI)conditions,the relative errors between VT and VAD become larger and more fluctuant.Moreover,it is found that the measurement uncertainty of VAD increases at a given elevation angle with the increasing measurement heights,which is caused by the horizontal homogeneity associated with the conical scanning area.Additionally,the simulated and measured results of four VADs indicate that a larger elevation angle corresponds to a lower measurement uncertainty for a given height.展开更多
Soil degradation through salinization and pollution by toxic compounds such as petroleum hydrocarbons(PHCs) in the coastal wetlands has become a significant threat to ecosystem health, biodiversity, and food security....Soil degradation through salinization and pollution by toxic compounds such as petroleum hydrocarbons(PHCs) in the coastal wetlands has become a significant threat to ecosystem health, biodiversity, and food security. However, traditional remediation technologies can generate secondary pollutants, incur high operating costs, and consume significant quantities of energy. Bioremediation, using plants, biochar, and microbes, is an innovative and cost-effective option to remediate contaminated soils. Biochar, as a plant/microbe growth enhancer, is a promising green approach for the sustainable phytoremediation of PHCs in salinized soils. This review therefore summarizes the effect of plant-and microbe-assisted biochar amendment technology for the remediation of PHCs and salinization. Plant-microbe interactions mediated rhizodegradation despite increasing hydrocarbon sorption. Overall, microbial respiration is more active in biochar amendments, due to faster biodegradation of PHCs and improved soil properties. The use of biochar, plants, and microbes is recommended,as it offers a practical and sustainable option, both ecologically and economically, for the remediation of PHCs and excess salinity. Further development of new green technologies is to be encouraged.展开更多
The calcite mylonites in the Xar Moron-Changchun shear zone show a significance dextral shearing characteristics. The asymmetric(σ-structure) calcite/quartz grains or aggregates, asymmetry of calcite c-axes fabric di...The calcite mylonites in the Xar Moron-Changchun shear zone show a significance dextral shearing characteristics. The asymmetric(σ-structure) calcite/quartz grains or aggregates, asymmetry of calcite c-axes fabric diagrams and the oblique foliation of recrystallized calcite grains correspond to a top-to-E shearing. Mineral deformation behaviors, twin morphology, C-axis EBSD fabrics, and quartz grain size-frequency diagrams demonstrate that the ductile shear zone was developed under conditions of greenschist facies, with the range of deformation temperatures from 200 to 300°C. These subgrains of host grains and surrounding recrystallized grains, strong undulose extinction, and slightly curved grain boundaries are probably results of intracrystalline deformation and dynamic recrystallization implying that the deformation took place within the dislocation-creep regime at shallow crustal levels. The calculated paleo-strain rates are between 10-7.87s-1 and 10-11.49s-1 with differential stresses of 32.63-63.94 MPa lying at the higher bound of typical strain rates in shear zones at crustal levels, and may indicate a relatively rapid deformation. The S-L-calcite tectonites have undergone a component of uplift which led to subhorizontal lifting in an already non-coaxial compressional deformation regime with a bulk pure shear-dominated general shear. This E-W large-scale dextral strike-slip movement is a consequence of the eastward extrusion of the Xing’an-Mongolian Orogenic Belt, and results from far-field forces associated with Late Triassic convergence domains after the final closure of the Paleo-Asian Ocean.展开更多
Locating seismic events is a central task for earthquake monitoring.Compared to arrival-based location methods,waveformbased location methods do not require picking phase arrivals and are more suitable for locating se...Locating seismic events is a central task for earthquake monitoring.Compared to arrival-based location methods,waveformbased location methods do not require picking phase arrivals and are more suitable for locating seismic events with noisy waveforms.Among waveform-based location methods,one approach is to stack different attributes of P and S waveforms around arrival times corresponding to potential event locations and origin times,and the maximum stacking values are assumed to indicate the correct event location and origin time.In this study,to obtain a high-resolution location image,we improve the waveform-based location method by applying a hybrid multiplicative imaging condition to characteristic functions of seismic waveforms.In our new stacking method,stations are divided into groups;characteristic functions of seismic waveforms recorded at stations in the same group are summed,and then multiplied among groups.We find that this approach can largely eliminate the cumulative effects of noise in the summation process and thus improve the resolution of location images.We test the new method and compare it to three other stacking methods,using both synthetic and real datasets that are related to induced seismicity occurring in petroleum/gas production.The test results confirm that the new stacking method can provide higher-resolution location images than those derived from currently used methods.展开更多
The Southern Annular Mode(SAM)plays an important role in regulating Southern Hemisphere extratropical circulation.State-of-the-art models exhibit intermodel spread in simulating long-term changes in the SAM.Results fr...The Southern Annular Mode(SAM)plays an important role in regulating Southern Hemisphere extratropical circulation.State-of-the-art models exhibit intermodel spread in simulating long-term changes in the SAM.Results from Atmospheric Model Intercomparison Project(AMIP)experiments from 28 models archived in CMIP5 show that the intermodel spread in the linear trend in the austral winter(June−July−August)SAM is significant,with an intermodel standard deviation of 0.28(10 yr)−1,larger than the multimodel ensemble mean of 0.18(10 yr)−1.This study explores potential factors underlying the model difference from the aspect of extratropical sea surface temperature(SST).Extratropical SST anomalies related to the SAM exhibit a dipole-like structure between middle and high latitudes,referred to as the Southern Ocean Dipole(SOD).The role of SOD-like SST anomalies in influencing the SAM is found in the AMIP simulations.Model performance in simulating the SAM trend is linked with model skill in reflecting the SOD−SAM relationship.Models with stronger linkage between the SOD and the SAM tend to simulate a stronger SAM trend.The explained variance is about 40%in the AMIP runs.These results suggest improved simulation of the SOD−SAM relationship may help reproduce long-term changes in the SAM.展开更多
The autumn Intertropical Convergence Zone(ITCZ)over the South China Sea(SCS)is typically held south of 10°N by prevailing northeasterly and weakening southwesterly winds.However,the ITCZ can move north,resulting ...The autumn Intertropical Convergence Zone(ITCZ)over the South China Sea(SCS)is typically held south of 10°N by prevailing northeasterly and weakening southwesterly winds.However,the ITCZ can move north,resulting in heavy rainfall in the northern SCS(NSCS).We investigate the mechanisms that drove the northward movement of the ITCZ and led to heavy non-tropical-cyclone rainfall over the NSCS in autumn of 2010.The results show that the rapid northward movement of the ITCZ on 1 and 2 October was caused by the joint influence of the equatorial easterlies(EE),southwesterly winds,and the easterly jet(EJ)in the NSCS.A high pressure center on the east side of Australia,strengthened by the quasi-biweekly oscillation and strong Walker circulation,was responsible for the EE to intensify and reach the SCS.The EE finally turned southeast and together with enhanced southwesterly winds associated with an anticyclone,pushed the ITCZ north.Meanwhile,the continental high moved east,which reduced the area of the EJ in the NSCS and made room for the ITCZ.Further regression analysis showed that the reduced area of the EJ and increased strength of the EE contributed significantly to the northward movement of the ITCZ.The enhancement of the EE preceded the northward movement of the ITCZ by six hours and pushed the ITCZ continually north.As the ITCZ approached 12°N,it not only transported warm moist air but also strengthened the dynamic field by transporting the positive vorticity horizontally and vertically which further contributed to the heavy rainfall.展开更多
The South Pacific Quadrupole(SPQ) is the extratropical South Pacific’s second principal sea surface temperature mode.Previous observational studies have shown that the SPQ promotes the onset of the El Nino-Southern O...The South Pacific Quadrupole(SPQ) is the extratropical South Pacific’s second principal sea surface temperature mode.Previous observational studies have shown that the SPQ promotes the onset of the El Nino-Southern Oscillation(ENSO).The present study evaluates and compares simulations of the SPQ-ENSO relationship by 20 climate models from CMIP6 and their corresponding 20 previous models from CMIP5.It is found that 16 of the20 pairs of models are able to consistently reproduce the spatial pattern of the SPQ.In terms of simulating the SPQ-ENSO relationship,9 of the 16 CMIP6 models show significant improvement over their previous CMIP5 models.The multi-model ensemble(MME) of these 16 CMIP6 models simulates the SPQ-ENSO connection more realistically than the CMIP5 MME.Further analysis shows that the performance of the model simulations in reproducing the SPQ-ENSO relationship is strongly dependent on their ability to simulate the SPQ-related surface air-sea coupling processes over the southwestern and southeastern South Pacific,as well as the response of the SPQ-related equatorial subsurface ocean temperature anomalies.The improvement of the CMIP6 models in simulating these two processes is responsible for the improved performance of the CMIP6 models over their CMIP5 counterparts in simulating the SPQ-ENSO relationship.展开更多
Post-collisional magmatism contains important clues for understanding the reworking and growth of continental crust,as well as lithospheric delamination and orogenic collapse.Early Devonian magmatism has been identifi...Post-collisional magmatism contains important clues for understanding the reworking and growth of continental crust,as well as lithospheric delamination and orogenic collapse.Early Devonian magmatism has been identified in the North Qilian Orogenic Belt(NQOB).This paper reports an integrated study of petrology,whole-rock geochemistry,Sm-Nd isotope and zircon U-Pb dating,as well as Lu-Hf isotopic data,for two Early Devonian intrusive plutons.The Yongchang and Chijin granites yield zircon U-Pb ages of 394-407 Ma and 414 Ma,respectively.Both of them are characterized by weakly peraluminous to metaluminous without typical aluminium-rich minerals,LREE-enriched patterns with negative Eu anomalies and a negative correlation between P_(2)O_(5) and SiO_(2) contents,consistent with geochemical features of I-type granitoids.Zircons from the studied granites display negative to weak positive ε_(Hf)(t)values(−5.7 to 2.1),which agree well with those of negative ε_(Nd)(t)values(−6.4 to−2.9)for the whole-rock samples,indicating that they were derived from the partial melting of Mesoproterozoic crust.Furthermore,low Sr/Y ratios(1.13-21.28)and high zircon saturation temperatures(745℃ to 839℃,with the majority being>800℃)demonstrated a relatively shallow depth level below the garnet stability field and an additional heat source.Taken together,the Early Devonian granitic magmatism could have been produced by the partial melting of ancient crustal materials heated by mantle-derived magmas at high-temperature and low-pressure conditions during postcollisional extensional collapse.The data obtained in this study,when viewed in conjunction with previous studies,provides more information about the tectonic processes that followed the closure of the North Qilian Ocean.The tectonic transition from continental collision to post-collisional delamination could be constrained to~430 Ma,which is provided by the sudden decrease of Sr/Y and La/Yb ratios and an increase in zircon ε_(Hf)(t)values for granitoids.A two-stage tectonic evolution model from continental collision to post-collisional extensional collapse for the NQOB includes(a)continental collision and crustal thickening during ca.455-430 Ma,characterized by granulite-facies metamorphism and widespread low-Mg adakitic magmatism;(b)post-collisional delamination of thickened continental crust and extensional collapse of orogen during ca.430-390 Ma,provided by coeval high-Mg adakitic magmatism,A-type granites and I-type granitoids with low Sr-Y ratios.展开更多
To investigate the stratosphere-troposphere exchange(STE)process induced by the gravity waves(GWs)caused by Typhoon Molave(2020)in the upper troposphere and lower stratosphere,we analyzed the ERA5 reanalysis data prov...To investigate the stratosphere-troposphere exchange(STE)process induced by the gravity waves(GWs)caused by Typhoon Molave(2020)in the upper troposphere and lower stratosphere,we analyzed the ERA5 reanalysis data provided by the European Centre for Medium-Range Weather Forecasts and the CMA Tropical Cyclone Best Track Dataset.We also adopted the mesoscale forecast model Weather Research and Forecasting model V4.3 for numerical simulation.Most of the previous studies were about typhoon-induced STE and typhoon-induced GWs,while our research focused on the STE caused by typhoon-induced gravity waves.Our analysis shows that most of the time,the gravity wave signal of Typhoon Molave appeared below the tropopause.It was stronger on the east side of the typhoon center(10°-20°N,110°-120°E)than on the west side,suggesting an eastward tilted structure with height increase.When the GWs in the upper troposphere and lower stratosphere region on the west side of the typhoon center broke up,it produced strong turbulence,resulting in stratosphere-troposphere exchange.At this time,the average potential vorticity vertical flux increased with the average ozone mass mixing ratio.The gravity wave events and STE process simulated by the WRF model were basically consistent with the results of ERA5 reanalysis data,but the time of gravity wave breaking was different.This study indicates that after the breaking of the GWs induced by typhoons,turbulent mixing will also be generated,and thus the STE.展开更多
Seismic source locations can characterize the spatial and temporal distributions of seismic sources,and can provide important basic data for earthquake disaster monitoring,fault activity characterization,and fracture ...Seismic source locations can characterize the spatial and temporal distributions of seismic sources,and can provide important basic data for earthquake disaster monitoring,fault activity characterization,and fracture growth interpretation.Waveform stacking-based location methods invert the source locations by focusing the source energy with multichannel waveforms,and these methods exhibit a high level of automation and noise-resistance.Taking the cross-correlation stacking(CCS)method as an example,this work attempts to study the influential factors of waveform stacking-based methods,and introduces a comprehensive performance evaluation scheme based on multiple parameters and indicators.The waveform data are from field monitoring of induced microseismicity in the Changning region(southern Sichuan Basin of China).Synthetic and field data tests reveal the impacts of three categories of factors on waveform stacking-based location:velocity model,monitoring array,and waveform complexity.The location performance is evaluated and further improved in terms of the source imaging resolution and location error.Denser array monitoring contributes to better constraining source depth and location reliability,but the combined impact of multiple factors,such as velocity model uncertainty and multiple seismic phases,increases the complexity of locating field microseismic events.Finally,the aspects of location uncertainty,phase detection,and artificial intelligencebased location are discussed.展开更多
This paper reviews recent progress made by Chinese scientists on the pathways of influence of the Northern Hemisphere mid-high latitudes on East Asian climate within the framework of a“coupled oceanic-atmospheric(lan...This paper reviews recent progress made by Chinese scientists on the pathways of influence of the Northern Hemisphere mid-high latitudes on East Asian climate within the framework of a“coupled oceanic-atmospheric(land-atmospheric or seaice-atmospheric)bridge”and“chain coupled bridge”.Four major categories of pathways are concentrated upon,as follows:Pathway A—from North Atlantic to East Asia;Pathway B—from the North Pacific to East Asia;Pathway C—from the Arctic to East Asia;and Pathway D—the synergistic effects of the mid-high latitudes and tropics.In addition,definitions of the terms“combined effect”,“synergistic effect”and“antagonistic effect”of two or more factors of influence or processes and their criteria are introduced,so as to objectively investigate those effects in future research.展开更多
Internal solitary waves(ISWs)always happen in marginal seas,where stable stratification exists.ISWs may carry large energy when they propagate and affect marine engineering constructions such as marine drilling platfo...Internal solitary waves(ISWs)always happen in marginal seas,where stable stratification exists.ISWs may carry large energy when they propagate and affect marine engineering constructions such as marine drilling platforms.Previous studies,including a large number of mooring observations and laboratory experiments,show the speed of ISWs will change when they pass by shelf slopes.Korteweg-de Vries(KdV)theory explain this phenomenon.In the paper,we use a laboratory experiment and a numerical model experiment to verify this theory.In the laboratory experiment,we injected two layers of water of different densities in a tank to simulate marine stratification and make ISWs.We use a CCD camera to record the whole process.The camera can take 16 photos per second.In the numerical experiment,we input the same original conditions as the laboratory one.The results of 18 different original conditions show the dimensionless factorδplays a key role in deciding the amplitudes and shapes of ISWs.The main conclusion also contains that small-amplitude waves match well with KdV theory while mKdV is better for largeamplitude waves.Whether the laboratory experiment or numerical experiment shows results with a high agreement.In future studies,we may use a numerical model with higher resolution to get analysis about phase speed and energy of ISWs.展开更多
Paleo-to Mesoproterozoic sedimentary rocks in the southern margin of the North China Craton(NCC)are represented by the Ruyang and Luoyu groups.We studied the sedimentary rocks from the Yunmengshan and Beidajian format...Paleo-to Mesoproterozoic sedimentary rocks in the southern margin of the North China Craton(NCC)are represented by the Ruyang and Luoyu groups.We studied the sedimentary rocks from the Yunmengshan and Beidajian formations of the Ruyang Group and the Cuizhuang and Sanjiaotang formations of the Luoyu Group.Detrital zircon grains from these formations have U–Pb age populations of 3.64–3.31 Ga,2.96–2.86 Ga,2.72–2.59 Ga,2.56–2.47 Ga,2.45–2.0 Ga,1.99–1.85 Ga and 1.84–1.65 Ga.The geochemical features of the sedimentary rocks suggest that some of the sediments were sourced from intermediate to felsic magmatic rocks.The age groups of the detrital zircon are roughly consistent with the tectono-thermal events in the southern margin of the NCC.The Hf isotopic compositions of detrital zircon from the sedimentary rocks in Ruyang and Luoyu groups suggest that significant crustal growth and reworking of the NCC took place during the Neoarchean and early-to mid-Paleoproterozoic,while crustal reworking at the Paleoarchean and late-Paleoproterozoic,and crustal growth at the Mesoarchean.We suggest the depositional times of the Ruyang Group and Luoyu Group are constrained to no older than 1.75–1.7 Ga and 1.7–1.65 Ga,respectively.Formation of late-Paleoproterozoic basins related to the strike slip and extrusion tectonics that cross-cut the NCC during the late Paleoproterozoic(<1.75 Ga),and the late Paleoproterozoic sedimentation once isochronous developed in the southern margin of the NCC through the Taihang region of the interior NCC and linked the Yanshan–Liaoxi regions of the northern NCC.展开更多
Maowei Sea(MWS) is the largest oyster maricuture bay in Southwest China. Surface water from 12 sampling sites were collected during the dry season to study the composition and distribution of different forms of nitrog...Maowei Sea(MWS) is the largest oyster maricuture bay in Southwest China. Surface water from 12 sampling sites were collected during the dry season to study the composition and distribution of different forms of nitrogen(N) and phosphorus(P) beginning from the inner bay to the bay mouth in the MWS. An improved multi-parameter eutrophication index was developed and applied for the evaluation of the water quality in the MWS. Dissolved inorganic nitrogen(DIN), dissolved organic nitrogen(DON), and particulate nitrogen(PN) averagely accounted for 11.28%, 65.32%, and 23.39% of total N(TN) pool, dissolved inorganic phosphorus(DIP), dissolved organic phosphorus(DOP), and particulate phosphorus(PP) averagely accounted for 54.58%, 30.31%, and 15.12% of total P(TP) pool, respectively. DON and DIP were respectively the dominant forms of N and P in surface water of the MWS, during the study period. Concentration trends of DIN, DIP, DOP, PN, dissolved silicate(DSi), total organic carbon(TOC), chemical oxygen demand(COD) decreased from the inner bay to the bay mouth, suggesting that the MWS may be largely influenced by land-based inputs. Based on nutrient contents and stoichiometry, it likely that phytoplankton growth in the MWS is strongly limited by DIP during the dry season. Results from the improved eutrophication index revealed that the water quality in the MWS is in a state of moderate to poor eutrophication(average EI = 0.953). The eutrophication state decreased from the inner bay to the bay mouth. Nitrate(NO3-N), DON, DIP, DOP, and DSi showed significant positive correlations with eutrophication index(r2 = 0.52 – 0.78, P < 0.05), implying that these nutrients are among the significant factors, which could be used in evaluating the eutrophication status of the MWS.展开更多
Predicting tropical cyclone(TC)genesis is of great societal importance but scientifically challenging.It requires fineresolution coupled models that properly represent air−sea interactions in the atmospheric responses...Predicting tropical cyclone(TC)genesis is of great societal importance but scientifically challenging.It requires fineresolution coupled models that properly represent air−sea interactions in the atmospheric responses to local warm sea surface temperatures and feedbacks,with aid from coherent coupled initialization.This study uses three sets of highresolution regional coupled models(RCMs)covering the Asia−Pacific(AP)region initialized with local observations and dynamically downscaled coupled data assimilation to evaluate the predictability of TC genesis in the West Pacific.The APRCMs consist of three sets of high-resolution configurations of the Weather Research and Forecasting−Regional Ocean Model System(WRF-ROMS):27-km WRF with 9-km ROMS,and 9-km WRF with 3-km ROMS.In this study,a 9-km WRF with 9-km ROMS coupled model system is also used in a case test for the predictability of TC genesis.Since the local sea surface temperatures and wind shear conditions that favor TC formation are better resolved,the enhanced-resolution coupled model tends to improve the predictability of TC genesis,which could be further improved by improving planetary boundary layer physics,thus resolving better air−sea and air−land interactions.展开更多
Well CSDP-2 is a fully coring deep drilling hole, penetrating the thick Paleozoic marine strata in the South Yellow Sea Basin(SYSB) in the lower Yangtze Block(LYB). Based on the petrological and geochemical analysis o...Well CSDP-2 is a fully coring deep drilling hole, penetrating the thick Paleozoic marine strata in the South Yellow Sea Basin(SYSB) in the lower Yangtze Block(LYB). Based on the petrological and geochemical analysis of 40 sandstone samples from the core CSDP-2, the provenance and tectonic features of Paleozoic detrital rocks from SYSB are analyzed and systematically delineated in this article. The results show that the Silurian – Carboniferous sandstones are mature sublitharenite, while the Permian sandstones are unstable feldspathic litharenite. The average CIA(chemical index of alteration) is 74.61, which reflects these sediments were derived from source rocks with moderate chemical weathering. The REE(rare earth element) patterns are characterized by LREE enrichment, flat HREE and obviously negative Eu anomaly, which are similar to that of the upper continental crust. Dickinson QFL discrimination results indicate the recycled orogeny provenance. Various diagrams for the discrimination of sedimentary provenance based on major and trace element data show all the sediments were derived predominantly from quartz sedimentary rocks, of which the Permian strata contain more felsic sedimentary rocks. Geochemical data for these detrital rocks suggest they occur at the passive continental margin and island arc settings, and the Permian sandstone presents active continental margin setting.展开更多
Over the past decades,jellyfish occurred increasingly and abundantly in coastal areas worldwide.Usually,biomass of jellyfish,especially when they bloom,can be determined by visual counting.However,tiny individuals of ...Over the past decades,jellyfish occurred increasingly and abundantly in coastal areas worldwide.Usually,biomass of jellyfish,especially when they bloom,can be determined by visual counting.However,tiny individuals of jellyfish(e.g.,planulae,polyps,and ephyrae)are difficult to detect in the field.In this study,species-specific quantitative real-time PCR assays(qPCR)(SYBR Green I)targeting the mitochondrial 16S rDNA(mt-16S rDNA)of jellyfish were developed and were used to estimate the distribution and seasonal fluctuations of four jellyfish species(Nemopilema nomurai,Cyanea nozakii,Rhopilema esculentum,and Aurelia coerulea)in Jiaozhou Bay(JZB),China in 2013.The mt-16S rDNA of A.coerulea and N.nomurai was detected in most of the survey months and it peaked in July(1.03×10^(4) copies/L)and September(1.08×10^(6) copies/L),respectively.The mt-16S rDNA of C.nozakii occurred from August to October only with monthly mean values of 7.18-46.17 copies/L and was mainly located from the middle part to the outer part of the bay.The mt-16S rDNA of R.esculentum was the least abundant among the four species and was detected in only one sample(B2 station in March),with a value of 88.49 copies/L.The Spearman correlation test revealed that phytoplankton biomass was significantly and positively correlated with the mt-16S rDNA abundance of A.coerulea(R=0.37,P<0.01)and negatively with the mt-16S rDNA of N.nomurai(R=-0.36,P<0.01).The qPCR assay will enable the identification and quantification of jellyfish species in their whole life history and can be used as an approach in combination of the traditional jellyfish survey.展开更多
The enzymes and the characteristics of the community of the petroleum-degrading bacteria play a crucial role in the crude oil biodegradation. The prediction of kinetics of the key groups of hydrocarbons in crude oil w...The enzymes and the characteristics of the community of the petroleum-degrading bacteria play a crucial role in the crude oil biodegradation. The prediction of kinetics of the key groups of hydrocarbons in crude oil was important to evaluate the bioremediation speed and constant. Most of the n-alkanes(C9-C29) were degraded in 25 days, and the average degradation rates of C_(18)~C_(27) higher than 100 μg g^(-1) d^(-1).The hopanes, such as H_(30), had a biodegradation rate more than 10 μg g^(-1) d^(-1). The related enzymes activities changed along with the crude oil biodegradation, especially dehydrogenase. The 16 S rRNA gene amplicon sequencing revealed that Proteobacteria, Firmcutes, Bacteroidetes, Actinobacteria, Acidobacteria were the main petroleum hydrocarbon degraders during the crude oil biodegradation, and the top two highest relative abundance of the genera were Alcaligenes and Acinetobacter. Acinetobacter presented positive correlation to biodegradation of n-alkanes and PAHs. Based on COG analysis, the largest group involved in the general function was amino acid transport and metabolism. The functional categories of bacterial communities were mainly focused on the carbohydrate and amino acid metabolism, xenobiotics biodegradation and metabolism, membrane transport, and so on. Overall, these findings highlight the potential guideline for more adequate monitoring of microbial degradation of crude oil.展开更多
基金financially co-supported by the National Key R&D Program of China (Grant No. 2017YFC0601401 and 2017YFC0601300-01)Self-determined Foundation of Key Laboratory of Mineral Resources Evaluation in Northeast Asia, Ministry of Natural Resources, China (Grant No. DBY–ZZ–18–09)
文摘The Jiutai area is tectonically situated at the eastern segment of the Central Asian Orogenic Belt(CAOB) and is close to the North China Craton(NCC) to the south, serving as an ideal place to investigations of the closure of the PaleoAsian Ocean(PAO). Sandstone samples collected from the Yangjiagou Formation and the Lujiatun Formation in this area have been studied in detail in terms of petrology, geochronology and geochemistry. The maximum depositional time of the Yangjiagou and Lujiatun formations has been constrained to early Middle Triassic(ca. 245 Ma) and middle Late Triassic(ca. 219 Ma), respectively. The Yangjiagou Formation, with a major provenance of dissected island arcs, is dominantly composed of Phanerozoic sediments from Northeastern China(NE China) massifs. The Lujiatun Formation, with major sediments from active continental margins, has a relatively larger proportion of Precambrian sediments, in which the ~1.85 Ga and ~2.5 Ga sediments are typical of the crystalline basements of the NCC and NE China massifs, which were uplifted and eroded during the closure of the PAO. Besides, both formations show the enrichment in LREEs and the depletion in HREEs, the common Eu negative anomalies, and trace element contents similar to that of the upper continental crust. Based on the provenance analysis of these two formations, the final closure time of the PAO in this area is constrained as from the early Middle Triassic(ca. 245 Ma) to the middle Late Triassic(ca. 219 Ma).
基金supported by the National Key Research and Development Program of China[grant number 2021YFC3001902,2022YFB3901705]the National Natural Science Foundation of China[grant number 42106182,U2106210]the Natural Science Foundation of Shandong Province[grant number ZR2021QD052].
文摘The accurate three-dimensional wind field obtained from a Doppler lidar not only helps to comprehend the refined structure of complex airflow but also provides important and valuable solutions for many fields.However,the underlying homogeneity assumption of the typical wind retrieval methods,such as Doppler Beam Swinging(DBS)and Velocity Azimuth Display(VAD)based on a single-lidar,will introduce the measurement uncertainty in complex terrain.In this paper,a new design of a wind measurement campaign involving seven lidars was carried out,which contained the three-lidar-based Virtual Tower(VT)using a time-space synchronization technique and four single-lidars with different elevation angles.This study investigates the performance of VT and VAD measurements under various conditions and evaluates the sensitivity of wind measurement uncertainty of VAD to the horizontal spatial-and probe volume-average effects associated with elevation angles of the laser beam.The inter-comparison results between VT and four VADs show consistent trends with small relative errors under neutral atmospheric conditions with weak wind velocity.Under convective or high Turbulence Intensity(TI)conditions,the relative errors between VT and VAD become larger and more fluctuant.Moreover,it is found that the measurement uncertainty of VAD increases at a given elevation angle with the increasing measurement heights,which is caused by the horizontal homogeneity associated with the conical scanning area.Additionally,the simulated and measured results of four VADs indicate that a larger elevation angle corresponds to a lower measurement uncertainty for a given height.
基金supported by the Shandong Provincial Key Research and Development Program of China— Major Science and Technology Innovation Project (No. 2018CXGC0304)the Shandong Provincial Natural Science Foundation of China (No. ZR2019MD017)the Chinese Government Scholarship (CSC)。
文摘Soil degradation through salinization and pollution by toxic compounds such as petroleum hydrocarbons(PHCs) in the coastal wetlands has become a significant threat to ecosystem health, biodiversity, and food security. However, traditional remediation technologies can generate secondary pollutants, incur high operating costs, and consume significant quantities of energy. Bioremediation, using plants, biochar, and microbes, is an innovative and cost-effective option to remediate contaminated soils. Biochar, as a plant/microbe growth enhancer, is a promising green approach for the sustainable phytoremediation of PHCs in salinized soils. This review therefore summarizes the effect of plant-and microbe-assisted biochar amendment technology for the remediation of PHCs and salinization. Plant-microbe interactions mediated rhizodegradation despite increasing hydrocarbon sorption. Overall, microbial respiration is more active in biochar amendments, due to faster biodegradation of PHCs and improved soil properties. The use of biochar, plants, and microbes is recommended,as it offers a practical and sustainable option, both ecologically and economically, for the remediation of PHCs and excess salinity. Further development of new green technologies is to be encouraged.
基金financially co-supported by the National Key R&D Program of China (Grant No.2017YFC0601401 and 2017YFC0601300-01)the National Natural Science Foundation of China (Grant no. 41602211 and 41230206)
文摘The calcite mylonites in the Xar Moron-Changchun shear zone show a significance dextral shearing characteristics. The asymmetric(σ-structure) calcite/quartz grains or aggregates, asymmetry of calcite c-axes fabric diagrams and the oblique foliation of recrystallized calcite grains correspond to a top-to-E shearing. Mineral deformation behaviors, twin morphology, C-axis EBSD fabrics, and quartz grain size-frequency diagrams demonstrate that the ductile shear zone was developed under conditions of greenschist facies, with the range of deformation temperatures from 200 to 300°C. These subgrains of host grains and surrounding recrystallized grains, strong undulose extinction, and slightly curved grain boundaries are probably results of intracrystalline deformation and dynamic recrystallization implying that the deformation took place within the dislocation-creep regime at shallow crustal levels. The calculated paleo-strain rates are between 10-7.87s-1 and 10-11.49s-1 with differential stresses of 32.63-63.94 MPa lying at the higher bound of typical strain rates in shear zones at crustal levels, and may indicate a relatively rapid deformation. The S-L-calcite tectonites have undergone a component of uplift which led to subhorizontal lifting in an already non-coaxial compressional deformation regime with a bulk pure shear-dominated general shear. This E-W large-scale dextral strike-slip movement is a consequence of the eastward extrusion of the Xing’an-Mongolian Orogenic Belt, and results from far-field forces associated with Late Triassic convergence domains after the final closure of the Paleo-Asian Ocean.
基金supported by the International Research Center of Big Data for Sustainable Development Goals [grant number CBAS2022GSP01]the National Natural Science Foundation of China [grant numbers 42276203 and 42030406]+1 种基金the Natural Science Foundation of Shandong Province [grant number ZR2021MD001]the Laoshan Laboratory [grant number LSKJ202204302].
基金supported by National Key R&D Program of China under grant 2018YFC1504102the National Natural Science Foundation of China under grant 41961134001。
文摘Locating seismic events is a central task for earthquake monitoring.Compared to arrival-based location methods,waveformbased location methods do not require picking phase arrivals and are more suitable for locating seismic events with noisy waveforms.Among waveform-based location methods,one approach is to stack different attributes of P and S waveforms around arrival times corresponding to potential event locations and origin times,and the maximum stacking values are assumed to indicate the correct event location and origin time.In this study,to obtain a high-resolution location image,we improve the waveform-based location method by applying a hybrid multiplicative imaging condition to characteristic functions of seismic waveforms.In our new stacking method,stations are divided into groups;characteristic functions of seismic waveforms recorded at stations in the same group are summed,and then multiplied among groups.We find that this approach can largely eliminate the cumulative effects of noise in the summation process and thus improve the resolution of location images.We test the new method and compare it to three other stacking methods,using both synthetic and real datasets that are related to induced seismicity occurring in petroleum/gas production.The test results confirm that the new stacking method can provide higher-resolution location images than those derived from currently used methods.
基金This work was jointly supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA19070402)a National Key Research and Development Project(Grant No.2018YFA0606404)the National Natural Science Foundation of China(Grant Nos.41790474 and 41775090).
文摘The Southern Annular Mode(SAM)plays an important role in regulating Southern Hemisphere extratropical circulation.State-of-the-art models exhibit intermodel spread in simulating long-term changes in the SAM.Results from Atmospheric Model Intercomparison Project(AMIP)experiments from 28 models archived in CMIP5 show that the intermodel spread in the linear trend in the austral winter(June−July−August)SAM is significant,with an intermodel standard deviation of 0.28(10 yr)−1,larger than the multimodel ensemble mean of 0.18(10 yr)−1.This study explores potential factors underlying the model difference from the aspect of extratropical sea surface temperature(SST).Extratropical SST anomalies related to the SAM exhibit a dipole-like structure between middle and high latitudes,referred to as the Southern Ocean Dipole(SOD).The role of SOD-like SST anomalies in influencing the SAM is found in the AMIP simulations.Model performance in simulating the SAM trend is linked with model skill in reflecting the SOD−SAM relationship.Models with stronger linkage between the SOD and the SAM tend to simulate a stronger SAM trend.The explained variance is about 40%in the AMIP runs.These results suggest improved simulation of the SOD−SAM relationship may help reproduce long-term changes in the SAM.
基金The research is supported by the Key Laboratory of South China Sea Meteorological Disaster Prevention and Mitigation of Hainan Province(Grant No.SCSF201906)the National Natural Science Foundation of China(Grant No.41975008)the Fundamental Research Funds for the Central Universities(Grant No.201861003).
文摘The autumn Intertropical Convergence Zone(ITCZ)over the South China Sea(SCS)is typically held south of 10°N by prevailing northeasterly and weakening southwesterly winds.However,the ITCZ can move north,resulting in heavy rainfall in the northern SCS(NSCS).We investigate the mechanisms that drove the northward movement of the ITCZ and led to heavy non-tropical-cyclone rainfall over the NSCS in autumn of 2010.The results show that the rapid northward movement of the ITCZ on 1 and 2 October was caused by the joint influence of the equatorial easterlies(EE),southwesterly winds,and the easterly jet(EJ)in the NSCS.A high pressure center on the east side of Australia,strengthened by the quasi-biweekly oscillation and strong Walker circulation,was responsible for the EE to intensify and reach the SCS.The EE finally turned southeast and together with enhanced southwesterly winds associated with an anticyclone,pushed the ITCZ north.Meanwhile,the continental high moved east,which reduced the area of the EJ in the NSCS and made room for the ITCZ.Further regression analysis showed that the reduced area of the EJ and increased strength of the EE contributed significantly to the northward movement of the ITCZ.The enhancement of the EE preceded the northward movement of the ITCZ by six hours and pushed the ITCZ continually north.As the ITCZ approached 12°N,it not only transported warm moist air but also strengthened the dynamic field by transporting the positive vorticity horizontally and vertically which further contributed to the heavy rainfall.
基金This research was jointly supported by the National Natural Science Foundation of China[Grant number 41975070]the State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences[Project number LTO1901].
文摘The South Pacific Quadrupole(SPQ) is the extratropical South Pacific’s second principal sea surface temperature mode.Previous observational studies have shown that the SPQ promotes the onset of the El Nino-Southern Oscillation(ENSO).The present study evaluates and compares simulations of the SPQ-ENSO relationship by 20 climate models from CMIP6 and their corresponding 20 previous models from CMIP5.It is found that 16 of the20 pairs of models are able to consistently reproduce the spatial pattern of the SPQ.In terms of simulating the SPQ-ENSO relationship,9 of the 16 CMIP6 models show significant improvement over their previous CMIP5 models.The multi-model ensemble(MME) of these 16 CMIP6 models simulates the SPQ-ENSO connection more realistically than the CMIP5 MME.Further analysis shows that the performance of the model simulations in reproducing the SPQ-ENSO relationship is strongly dependent on their ability to simulate the SPQ-related surface air-sea coupling processes over the southwestern and southeastern South Pacific,as well as the response of the SPQ-related equatorial subsurface ocean temperature anomalies.The improvement of the CMIP6 models in simulating these two processes is responsible for the improved performance of the CMIP6 models over their CMIP5 counterparts in simulating the SPQ-ENSO relationship.
基金supported by the Natural Science Foundation of Shandong Province(Grant No.ZR2022QD055)the Taishan Scholars(Grant No.tstp 20231214)the National Natural Science Foundation of China(Grant No.42372247).
文摘Post-collisional magmatism contains important clues for understanding the reworking and growth of continental crust,as well as lithospheric delamination and orogenic collapse.Early Devonian magmatism has been identified in the North Qilian Orogenic Belt(NQOB).This paper reports an integrated study of petrology,whole-rock geochemistry,Sm-Nd isotope and zircon U-Pb dating,as well as Lu-Hf isotopic data,for two Early Devonian intrusive plutons.The Yongchang and Chijin granites yield zircon U-Pb ages of 394-407 Ma and 414 Ma,respectively.Both of them are characterized by weakly peraluminous to metaluminous without typical aluminium-rich minerals,LREE-enriched patterns with negative Eu anomalies and a negative correlation between P_(2)O_(5) and SiO_(2) contents,consistent with geochemical features of I-type granitoids.Zircons from the studied granites display negative to weak positive ε_(Hf)(t)values(−5.7 to 2.1),which agree well with those of negative ε_(Nd)(t)values(−6.4 to−2.9)for the whole-rock samples,indicating that they were derived from the partial melting of Mesoproterozoic crust.Furthermore,low Sr/Y ratios(1.13-21.28)and high zircon saturation temperatures(745℃ to 839℃,with the majority being>800℃)demonstrated a relatively shallow depth level below the garnet stability field and an additional heat source.Taken together,the Early Devonian granitic magmatism could have been produced by the partial melting of ancient crustal materials heated by mantle-derived magmas at high-temperature and low-pressure conditions during postcollisional extensional collapse.The data obtained in this study,when viewed in conjunction with previous studies,provides more information about the tectonic processes that followed the closure of the North Qilian Ocean.The tectonic transition from continental collision to post-collisional delamination could be constrained to~430 Ma,which is provided by the sudden decrease of Sr/Y and La/Yb ratios and an increase in zircon ε_(Hf)(t)values for granitoids.A two-stage tectonic evolution model from continental collision to post-collisional extensional collapse for the NQOB includes(a)continental collision and crustal thickening during ca.455-430 Ma,characterized by granulite-facies metamorphism and widespread low-Mg adakitic magmatism;(b)post-collisional delamination of thickened continental crust and extensional collapse of orogen during ca.430-390 Ma,provided by coeval high-Mg adakitic magmatism,A-type granites and I-type granitoids with low Sr-Y ratios.
基金Guangdong Basic and Applied Basic Research Foundation(2023A1515011323)National Natural Science Foun-dation of China(42130604,42130605,72293604)+4 种基金Guangdong Provincial Observation and Research Station for Tropical Ocean Environment in Western Coastal Waters(GSTOEW)First-Class Discipline Plan of Guangdong Province(080503032101,231420003)Fundamental Research Funds for the Central Universities(202362001,202072010)China Scholarship Council(202208440223)Natural Science Foundation of Shanghai(23ZR1473800)。
文摘To investigate the stratosphere-troposphere exchange(STE)process induced by the gravity waves(GWs)caused by Typhoon Molave(2020)in the upper troposphere and lower stratosphere,we analyzed the ERA5 reanalysis data provided by the European Centre for Medium-Range Weather Forecasts and the CMA Tropical Cyclone Best Track Dataset.We also adopted the mesoscale forecast model Weather Research and Forecasting model V4.3 for numerical simulation.Most of the previous studies were about typhoon-induced STE and typhoon-induced GWs,while our research focused on the STE caused by typhoon-induced gravity waves.Our analysis shows that most of the time,the gravity wave signal of Typhoon Molave appeared below the tropopause.It was stronger on the east side of the typhoon center(10°-20°N,110°-120°E)than on the west side,suggesting an eastward tilted structure with height increase.When the GWs in the upper troposphere and lower stratosphere region on the west side of the typhoon center broke up,it produced strong turbulence,resulting in stratosphere-troposphere exchange.At this time,the average potential vorticity vertical flux increased with the average ozone mass mixing ratio.The gravity wave events and STE process simulated by the WRF model were basically consistent with the results of ERA5 reanalysis data,but the time of gravity wave breaking was different.This study indicates that after the breaking of the GWs induced by typhoons,turbulent mixing will also be generated,and thus the STE.
基金supported by National Natural Science Foundation of China(Nos.42374076,42174128 and 42004115)Natural Science Foundation for Excellent Young Scholars of Hunan Province,China(No.2022JJ 20057)+1 种基金Central South University Innovation-Driven Research Programme(No.2023CXQD063)the Guangdong Provincial Key Laboratory of Geophysical High-resolution Imaging Technology(No.2022B1212010002).
文摘Seismic source locations can characterize the spatial and temporal distributions of seismic sources,and can provide important basic data for earthquake disaster monitoring,fault activity characterization,and fracture growth interpretation.Waveform stacking-based location methods invert the source locations by focusing the source energy with multichannel waveforms,and these methods exhibit a high level of automation and noise-resistance.Taking the cross-correlation stacking(CCS)method as an example,this work attempts to study the influential factors of waveform stacking-based methods,and introduces a comprehensive performance evaluation scheme based on multiple parameters and indicators.The waveform data are from field monitoring of induced microseismicity in the Changning region(southern Sichuan Basin of China).Synthetic and field data tests reveal the impacts of three categories of factors on waveform stacking-based location:velocity model,monitoring array,and waveform complexity.The location performance is evaluated and further improved in terms of the source imaging resolution and location error.Denser array monitoring contributes to better constraining source depth and location reliability,but the combined impact of multiple factors,such as velocity model uncertainty and multiple seismic phases,increases the complexity of locating field microseismic events.Finally,the aspects of location uncertainty,phase detection,and artificial intelligencebased location are discussed.
基金supported by the National Natural Science Foundation of China(41790474)the State Oceanic Administration International Cooperation Program on Global Change and Air–Sea Interactions(GASI-IPOVAI-03)
文摘This paper reviews recent progress made by Chinese scientists on the pathways of influence of the Northern Hemisphere mid-high latitudes on East Asian climate within the framework of a“coupled oceanic-atmospheric(land-atmospheric or seaice-atmospheric)bridge”and“chain coupled bridge”.Four major categories of pathways are concentrated upon,as follows:Pathway A—from North Atlantic to East Asia;Pathway B—from the North Pacific to East Asia;Pathway C—from the Arctic to East Asia;and Pathway D—the synergistic effects of the mid-high latitudes and tropics.In addition,definitions of the terms“combined effect”,“synergistic effect”and“antagonistic effect”of two or more factors of influence or processes and their criteria are introduced,so as to objectively investigate those effects in future research.
基金Supported by the Key Program of National Natural Science Foundation of China(No.91958206)the Fundamental Research Funds for the Central Universities(No.201813024)+3 种基金the China’s National Key Research and Development Projects(No.2016YFA0601803)the Qingdao National Laboratory for Marine Science and Technology(No.2017ASKJ01)the National Natural Science Foundation of China(Nos.41490641,41521091,U1606402)the Taishan Scholars Program。
文摘Internal solitary waves(ISWs)always happen in marginal seas,where stable stratification exists.ISWs may carry large energy when they propagate and affect marine engineering constructions such as marine drilling platforms.Previous studies,including a large number of mooring observations and laboratory experiments,show the speed of ISWs will change when they pass by shelf slopes.Korteweg-de Vries(KdV)theory explain this phenomenon.In the paper,we use a laboratory experiment and a numerical model experiment to verify this theory.In the laboratory experiment,we injected two layers of water of different densities in a tank to simulate marine stratification and make ISWs.We use a CCD camera to record the whole process.The camera can take 16 photos per second.In the numerical experiment,we input the same original conditions as the laboratory one.The results of 18 different original conditions show the dimensionless factorδplays a key role in deciding the amplitudes and shapes of ISWs.The main conclusion also contains that small-amplitude waves match well with KdV theory while mKdV is better for largeamplitude waves.Whether the laboratory experiment or numerical experiment shows results with a high agreement.In future studies,we may use a numerical model with higher resolution to get analysis about phase speed and energy of ISWs.
基金financially funded by the National Key Research and Development Program of China (No. 2016YFC0601002)Opening Foundation of State Key Laboratory of Continental Dynamics, Northwest University (No. 17LCD05)+3 种基金National Science and Technology Major Project (No. 2016ZX05004001)National Natural Science Foundation of China (No. 41602042)Fundamental Research Funds for the Central Universities (No. 201912026)supported by Taishan Scholar Program to Prof. Sanzhong Li
文摘Paleo-to Mesoproterozoic sedimentary rocks in the southern margin of the North China Craton(NCC)are represented by the Ruyang and Luoyu groups.We studied the sedimentary rocks from the Yunmengshan and Beidajian formations of the Ruyang Group and the Cuizhuang and Sanjiaotang formations of the Luoyu Group.Detrital zircon grains from these formations have U–Pb age populations of 3.64–3.31 Ga,2.96–2.86 Ga,2.72–2.59 Ga,2.56–2.47 Ga,2.45–2.0 Ga,1.99–1.85 Ga and 1.84–1.65 Ga.The geochemical features of the sedimentary rocks suggest that some of the sediments were sourced from intermediate to felsic magmatic rocks.The age groups of the detrital zircon are roughly consistent with the tectono-thermal events in the southern margin of the NCC.The Hf isotopic compositions of detrital zircon from the sedimentary rocks in Ruyang and Luoyu groups suggest that significant crustal growth and reworking of the NCC took place during the Neoarchean and early-to mid-Paleoproterozoic,while crustal reworking at the Paleoarchean and late-Paleoproterozoic,and crustal growth at the Mesoarchean.We suggest the depositional times of the Ruyang Group and Luoyu Group are constrained to no older than 1.75–1.7 Ga and 1.7–1.65 Ga,respectively.Formation of late-Paleoproterozoic basins related to the strike slip and extrusion tectonics that cross-cut the NCC during the late Paleoproterozoic(<1.75 Ga),and the late Paleoproterozoic sedimentation once isochronous developed in the southern margin of the NCC through the Taihang region of the interior NCC and linked the Yanshan–Liaoxi regions of the northern NCC.
基金the financial support of the National Natural Science Foundation of China (Nos. 41966002 and 41706083)the Natural Science Foundation of Guangxi (Nos. 2018GXNSFAA281295, 2018GX NSFDA281025, 2017GXNSFBA198135 and 2016GX NSFBA380108)+3 种基金the Science and Technology Plan Projects of Guangxi Province (No. 2017AB43024)the Research Startup Fund of Beibu Gulf University (No. 2017 KYQD218)the ‘Marine Ecological Environment’ Academician Workstation Capacity Building of Guangxi (No. Gui Science AD17129046)the Innovation and Entrepreneurship Education (No. 201911607014)。
文摘Maowei Sea(MWS) is the largest oyster maricuture bay in Southwest China. Surface water from 12 sampling sites were collected during the dry season to study the composition and distribution of different forms of nitrogen(N) and phosphorus(P) beginning from the inner bay to the bay mouth in the MWS. An improved multi-parameter eutrophication index was developed and applied for the evaluation of the water quality in the MWS. Dissolved inorganic nitrogen(DIN), dissolved organic nitrogen(DON), and particulate nitrogen(PN) averagely accounted for 11.28%, 65.32%, and 23.39% of total N(TN) pool, dissolved inorganic phosphorus(DIP), dissolved organic phosphorus(DOP), and particulate phosphorus(PP) averagely accounted for 54.58%, 30.31%, and 15.12% of total P(TP) pool, respectively. DON and DIP were respectively the dominant forms of N and P in surface water of the MWS, during the study period. Concentration trends of DIN, DIP, DOP, PN, dissolved silicate(DSi), total organic carbon(TOC), chemical oxygen demand(COD) decreased from the inner bay to the bay mouth, suggesting that the MWS may be largely influenced by land-based inputs. Based on nutrient contents and stoichiometry, it likely that phytoplankton growth in the MWS is strongly limited by DIP during the dry season. Results from the improved eutrophication index revealed that the water quality in the MWS is in a state of moderate to poor eutrophication(average EI = 0.953). The eutrophication state decreased from the inner bay to the bay mouth. Nitrate(NO3-N), DON, DIP, DOP, and DSi showed significant positive correlations with eutrophication index(r2 = 0.52 – 0.78, P < 0.05), implying that these nutrients are among the significant factors, which could be used in evaluating the eutrophication status of the MWS.
基金supported by the National Key Research&Development Program of China(Grant Nos.2017YFC1404100 and 2017YFC1404104)the National Natural Science Foundation of China(Grant Nos.41775100 and 41830964)。
文摘Predicting tropical cyclone(TC)genesis is of great societal importance but scientifically challenging.It requires fineresolution coupled models that properly represent air−sea interactions in the atmospheric responses to local warm sea surface temperatures and feedbacks,with aid from coherent coupled initialization.This study uses three sets of highresolution regional coupled models(RCMs)covering the Asia−Pacific(AP)region initialized with local observations and dynamically downscaled coupled data assimilation to evaluate the predictability of TC genesis in the West Pacific.The APRCMs consist of three sets of high-resolution configurations of the Weather Research and Forecasting−Regional Ocean Model System(WRF-ROMS):27-km WRF with 9-km ROMS,and 9-km WRF with 3-km ROMS.In this study,a 9-km WRF with 9-km ROMS coupled model system is also used in a case test for the predictability of TC genesis.Since the local sea surface temperatures and wind shear conditions that favor TC formation are better resolved,the enhanced-resolution coupled model tends to improve the predictability of TC genesis,which could be further improved by improving planetary boundary layer physics,thus resolving better air−sea and air−land interactions.
基金financially supported by the National Natural Science Foundation of China (Nos.41776081, 41210005)the China Geological Survey Project (No.DD20160147)Aoshan Science and Technology Innovation Project of Qingdao Pilot National Laboratory for Marine Science and Technology (No.2015ASKJ03)。
文摘Well CSDP-2 is a fully coring deep drilling hole, penetrating the thick Paleozoic marine strata in the South Yellow Sea Basin(SYSB) in the lower Yangtze Block(LYB). Based on the petrological and geochemical analysis of 40 sandstone samples from the core CSDP-2, the provenance and tectonic features of Paleozoic detrital rocks from SYSB are analyzed and systematically delineated in this article. The results show that the Silurian – Carboniferous sandstones are mature sublitharenite, while the Permian sandstones are unstable feldspathic litharenite. The average CIA(chemical index of alteration) is 74.61, which reflects these sediments were derived from source rocks with moderate chemical weathering. The REE(rare earth element) patterns are characterized by LREE enrichment, flat HREE and obviously negative Eu anomaly, which are similar to that of the upper continental crust. Dickinson QFL discrimination results indicate the recycled orogeny provenance. Various diagrams for the discrimination of sedimentary provenance based on major and trace element data show all the sediments were derived predominantly from quartz sedimentary rocks, of which the Permian strata contain more felsic sedimentary rocks. Geochemical data for these detrital rocks suggest they occur at the passive continental margin and island arc settings, and the Permian sandstone presents active continental margin setting.
基金Supported by the National Key Research and Development Program of China(Nos.2017YFC1404404,2017YFC1404402)the National Natural Science Foundation of China(No.41906112)the Scientific and Technological Innovation Project of the Qingdao National Laboratory for Marine Science and Technology(No.2016ASKJ02)。
文摘Over the past decades,jellyfish occurred increasingly and abundantly in coastal areas worldwide.Usually,biomass of jellyfish,especially when they bloom,can be determined by visual counting.However,tiny individuals of jellyfish(e.g.,planulae,polyps,and ephyrae)are difficult to detect in the field.In this study,species-specific quantitative real-time PCR assays(qPCR)(SYBR Green I)targeting the mitochondrial 16S rDNA(mt-16S rDNA)of jellyfish were developed and were used to estimate the distribution and seasonal fluctuations of four jellyfish species(Nemopilema nomurai,Cyanea nozakii,Rhopilema esculentum,and Aurelia coerulea)in Jiaozhou Bay(JZB),China in 2013.The mt-16S rDNA of A.coerulea and N.nomurai was detected in most of the survey months and it peaked in July(1.03×10^(4) copies/L)and September(1.08×10^(6) copies/L),respectively.The mt-16S rDNA of C.nozakii occurred from August to October only with monthly mean values of 7.18-46.17 copies/L and was mainly located from the middle part to the outer part of the bay.The mt-16S rDNA of R.esculentum was the least abundant among the four species and was detected in only one sample(B2 station in March),with a value of 88.49 copies/L.The Spearman correlation test revealed that phytoplankton biomass was significantly and positively correlated with the mt-16S rDNA abundance of A.coerulea(R=0.37,P<0.01)and negatively with the mt-16S rDNA of N.nomurai(R=-0.36,P<0.01).The qPCR assay will enable the identification and quantification of jellyfish species in their whole life history and can be used as an approach in combination of the traditional jellyfish survey.
基金funded by the Shandong Provincial Natural Science Foundation [Grant number: ZR2018MD018]Yantai University Doctoral Start-up Foundation [Grant number: HX2018B32]Shandong Key Laboratory of Marine Ecological Restoration (Grant number: 201919)。
文摘The enzymes and the characteristics of the community of the petroleum-degrading bacteria play a crucial role in the crude oil biodegradation. The prediction of kinetics of the key groups of hydrocarbons in crude oil was important to evaluate the bioremediation speed and constant. Most of the n-alkanes(C9-C29) were degraded in 25 days, and the average degradation rates of C_(18)~C_(27) higher than 100 μg g^(-1) d^(-1).The hopanes, such as H_(30), had a biodegradation rate more than 10 μg g^(-1) d^(-1). The related enzymes activities changed along with the crude oil biodegradation, especially dehydrogenase. The 16 S rRNA gene amplicon sequencing revealed that Proteobacteria, Firmcutes, Bacteroidetes, Actinobacteria, Acidobacteria were the main petroleum hydrocarbon degraders during the crude oil biodegradation, and the top two highest relative abundance of the genera were Alcaligenes and Acinetobacter. Acinetobacter presented positive correlation to biodegradation of n-alkanes and PAHs. Based on COG analysis, the largest group involved in the general function was amino acid transport and metabolism. The functional categories of bacterial communities were mainly focused on the carbohydrate and amino acid metabolism, xenobiotics biodegradation and metabolism, membrane transport, and so on. Overall, these findings highlight the potential guideline for more adequate monitoring of microbial degradation of crude oil.
