Effective conservation relies on robust assessments;however,the lack of waterbird data in the Yellow River Basin(YRB)has led to an underestimation of key habitat significance.This study addressed this gap by evaluatin...Effective conservation relies on robust assessments;however,the lack of waterbird data in the Yellow River Basin(YRB)has led to an underestimation of key habitat significance.This study addressed this gap by evaluating YRB wetland conservation importance using waterbirds as indicators and applying Ramsar,Important Bird Areas(IBA),and East Asian-Australasian Flyway(EAAF)criteria.We integrated coordinated surveys with citizen science data,creating a framework that tackles data deficiencies along the under-monitored Central Asian Flyway(CAF).Our analysis identified 75 priority wetlands,supporting 15 threatened species and 49 exceeding global/flyway 1%thresholds,highlighting the basin's biodiversity.We observed strong seasonal habitat use,with high-altitude wetlands vital for breeding and migration,and the Yellow River Delta providing year-round refuge.This research also provided data to refine Baer's Pochard population estimates.Alarmingly,one-third of the identified priority areas,primarily rivers and lakes,remain unprotected.To address this,we recommend systematic surveys,enhanced protected areas,OECMs,and targeted wetland restoration.This study underscores the YRB's role in regional conservation and provides essential data for adaptive management,particularly emphasizing the CAF's importance.展开更多
The onset,cessation,and length of the rainy season are crucial for global water resources,agricultural practices,and food security.However,the response of precipitation seasonality to global warming remains uncertain....The onset,cessation,and length of the rainy season are crucial for global water resources,agricultural practices,and food security.However,the response of precipitation seasonality to global warming remains uncertain.In this study,we analyze how global warming levels(GWLs)of 1.5℃ and 2℃ could affect the timing of rainfall onset(RODs),rainfall cessation(RCDs),and the overall duration of the rainy season(LRS)over global land monsoon(GLM)regions using simulations from CMIP6 under the SSP2-4.5 and SSP5-8.5 scenarios.With high model consensus,our results reveal that RODs are projected to occur later over Southern Africa,North Africa,and South America,but earlier over South Asia and Australia,in a warmer climate.The projected early RODs in Australia are more pronounced at the 2℃ GWL under SSP5-8.5.On the other hand,early RCDs are projected over South America and East Asia,while late RCDs are projected over North Africa,with high inter-model agreement.These changes are associated with a future decrease in LRS in most GLM regions.Additionally,we found that continuous warming over 1.5℃ will further reduce the length of the rainy season,especially over the South America,North Africa,and Southern Africa monsoon regions.The findings underscore the urgent need to mitigate global warming.展开更多
Fire season affects the dynamic changes of post-fire vegetation communities and carbon emissions.Analyzing its global patterns supports understanding of the ecological impacts of fires and responses of fires to climat...Fire season affects the dynamic changes of post-fire vegetation communities and carbon emissions.Analyzing its global patterns supports understanding of the ecological impacts of fires and responses of fires to climate change.Meteorological variables have been widely used to quantify fire season in current studies.However,their results can not be used to assess climate impacts on the seasonality of fire activities.Here we utilized satellite-based Moderate Resolution Imaging Spectroradiometer(MODIS)burned area data from 2001 to 2022 to identify global fire season types based on the number of peaks within a year.Using satellite data and innovatively processing the data to obtain a more accurate length of the fire season.We divided fire season types and examined the spatial distribution of fire season types across the Koppen-Geiger climate(KGC)zones.At a global scale,we identified three major fire season types,including unimodal(31.25%),bimodal(52.07%),and random(16.69%).The unimodal fire season primarily occurs in boreal and tropical regions lasting about 2.7 mon.In comparison,temperate ecosystems tend to have a longer fire season(3 mon)with two peaks throughout the year.The KGC zones show divergent contributions from the fire season types,indicating potential impacts of the climatic conditions on fire seasonality in these regions.展开更多
Approximately 3.44 billion tons of copper mine tailings(MT)were produced globally in 2018 with an increase of 45%from 2010.Significant efforts are being made to manage these tailings through storage facilities,recycli...Approximately 3.44 billion tons of copper mine tailings(MT)were produced globally in 2018 with an increase of 45%from 2010.Significant efforts are being made to manage these tailings through storage facilities,recycling,and reuse in different industries.Currently,a large portion of tailings are managed through the tailing storage facilities(TSF)where these tailings undergo hydro-thermal-mechanical stresses with seasonal cycles which are not comprehensively understood.This study presents an investigative study to evaluate the performance of control and cement-stabilized copper MT under the influence of seasonal cycles,freeze-thaw(F-T)and wet-dry(W-D)conditions,representing the seasonal variability in the cold and arid regions.The control and cement-stabilized MT samples were subjected to a maximum of 12 F-T and 12 W-D cycles and corresponding micro-and-macro behavior was investigated through scanning electron microscope(SEM),volumetric strain(εvT,wet density(r),moisture content loss,and unconfined compressive strength(UCS)tests.The results indicated the vulnerability of Copper MT to 67%and 75%strength loss reaching residual states with 12 F-T and 8 W-D cycles,respectively.Whereas the stabilized MT retained 39%-55%and 16%-34%strength with F-T and W-D cycles,demonstrating increased durability.This research highlights the impact of seasonal cycles and corresponding strength-deformation characteristics of control and stabilized Copper MT in cold and arid regions.展开更多
The Himalayan monal(Lophophorus impejanus),Nepal’s national bird,is a protected species facing significant conservation challenges.Understanding the distribution and habitat preferences of the Himalayan monal(HM)is c...The Himalayan monal(Lophophorus impejanus),Nepal’s national bird,is a protected species facing significant conservation challenges.Understanding the distribution and habitat preferences of the Himalayan monal(HM)is crucial for its conservation.This study was conducted in the Langtang National Park(LNP),Nepal using the route census method during both winter(November/December 2022)and summer(June 2023)seasons to examine the seasonal variation in HM’s elevational distribution and habitat preference.Further,we assessed their conservation threats by conducting a semi-structured questionnaire survey with the local residents.During the winter period,the HMs preferred grassland habitats,while in the summer,their preference shifted to shrubland and barren area.HM abundance was negatively associated with the Normalized Differential Vegetation Index(NDVI)and the shortest distance from the survey trails in the winter.The HMs actively avoided areas with high anthropogenic pressure.In the summer,they showed a wider elevational range up to 4400 m above sea level(a.s.l.),with a higher sighting frequency between 3600 and 3900 m a.s.l.The questionnaire survey of the local residents revealed that anthropogenic pressure such as poaching and free-ranging livestock grazing are the major threats to the species in the study area.This study provides valuable insight into the complex habitat preferences and critical threats faced by the HMs in LNP and underscores the urgent need for targeted conservation action.展开更多
Halocarbons play a vital role in ozone depletion and global warming,and are regulated by the Montreal Protocol(MP)and its amendments.China has been identified as an important contributor to the halocarbon emissions,bu...Halocarbons play a vital role in ozone depletion and global warming,and are regulated by the Montreal Protocol(MP)and its amendments.China has been identified as an important contributor to the halocarbon emissions,but the regional sources of halocarbons in China are not yet well comprehended.To investigate the characteristics,emissions,and source profiles,this study conducted a field campaign in Xiamen,a coastal city in southeastern China.Higher enhancements were found in the unregulated halocarbons(CH_(3)Cl,CH_(2)Cl_(2),CHCl_(3))than in the MP eliminated species(CCl_(4),CH_(3)Br)and theMP controlled species(HCFCs,HFCs).Many of the measured halocarbons varied seasonally and regionally,depending on the anthropogenic sources and atmospheric transport.Backward trajectory analysis showed that the air masses from inland were polluted over Shandong,Hebei,and northern Fujian in the cold season,while the air masses fromthe sea in the warm season were clean.Different air masses in two seasons were associated with the halocarbon patterns in the study area.Industrial activities,especially solvent usage,were the primary sources of halocarbons.The emission hot spots in Fujian Province were concentrated in Sanming,Fuzhou,and Xiamen,and the unregulated halocarbons made the largest contribution.This study provides an insight for a deep understanding of the characteristics and potential sources of halocarbons,and for strengthened management of halocarbons in China.展开更多
Wetland degradation is an escalating global challenge with profound impacts on animal diversity,particularly during successional processes.Birds,as highly mobile and environmentally sensitive organisms,serve as effect...Wetland degradation is an escalating global challenge with profound impacts on animal diversity,particularly during successional processes.Birds,as highly mobile and environmentally sensitive organisms,serve as effective indicators of ecological change.While previous studies have primarily focused on local community structures and species diversity during a specific season,there is a need to extend the research timeframe and explore broader spatial variations.Additionally,expanding from simple species diversity indices to more multidimensional diversity indices would provide a more comprehensive understanding of wetland health and resilience.To address these gaps,we investigated the effects of wetland degradation on bird diversity across taxonomic,phylogenetic,and functional dimensions in the Zoige Wetland,a plateau meadow wetland biodiversity hotspot.Surveys were conducted during both breeding(summer)and overwintering(winter)seasons across 20 transects in 5 sampling areas,representing 4 degradation levels(pristine,low,medium,and high).Our study recorded a total of 106 bird species from 32 families and 14 orders,revealing distinct seasonal patterns in bird community composition and diversity.Biodiversity indices were significantly higher in pristine and low-degraded wetlands,particularly benefiting waterfowl(Anseriformes,Ciconiiformes)and wading birds(Charadriiformes)in winter,when these areas provided superior food resources and habitat conditions.In contrast,medium and highly degraded wetlands supported increased numbers of terrestrial birds(Passeriformes)and raptors(Accipitriformes,Falconiformes).Seasonal differences in taxonomic,phylogenetic,and functional diversity indices highlighted the contrasting ecological roles of wetlands during breeding and overwintering periods.Furthermore,indicator species analysis revealed key species associated with specific degradation levels and seasons,providing valuable insights into wetland health.This study underscores the importance of spatiotemporal dynamics in understanding avian responses to wetland degradation.By linking seasonal patterns of bird diversity to habitat conditions,our findings contribute to conservation efforts and provide a framework for assessing wetland degradation and its ecological impacts.展开更多
A remarkable marine heatwave,known as the“Blob”,occurred in the Northeast Pacific Ocean from late 2013 to early 2016,which displayed strong warm anomalies extending from the surface to a depth of 300 m.This study em...A remarkable marine heatwave,known as the“Blob”,occurred in the Northeast Pacific Ocean from late 2013 to early 2016,which displayed strong warm anomalies extending from the surface to a depth of 300 m.This study employed two assimilation schemes based on the global Climate Forecast System of Nanjing University of Information Science(NUIST-CFS 1.0)to investigate the impact of ocean data assimilation on the seasonal prediction of this extreme marine heatwave.The sea surface temperature(SST)nudging scheme assimilates SST only,while the deterministic ensemble Kalman filter(EnKF)scheme assimilates observations from the surface to the deep ocean.The latter notably improves the forecasting skill for subsurface temperature anomalies,especially at the depth of 100-300 m(the lower layer),outperforming the SST nudging scheme.It excels in predicting both horizontal and vertical heat transport in the lower layer,contributing to improved forecasts of the lower-layer warming during the Blob.These improvements stem from the assimilation of subsurface observational data,which are important in predicting the upper-ocean conditions.The results suggest that assimilating ocean data with the EnKF scheme significantly enhances the accuracy in predicting subsurface temperature anomalies during the Blob and offers better understanding of its underlying mechanisms.展开更多
The symbiotic association between reef-building corals and Symbiodiniaceae is pivotal for coral reef ecosystems,yet remains susceptible to environmental factors.Currently,there is a dearth of research examining season...The symbiotic association between reef-building corals and Symbiodiniaceae is pivotal for coral reef ecosystems,yet remains susceptible to environmental factors.Currently,there is a dearth of research examining seasonal fluctuations in coral-associated Symbiodiniaceae communities.In this study,we investigated the seasonal dynamics of Symbiodiniaceae communities associated with coral species in the Luhuitou coral reef using high-throughput sequencing techniques and SymPortal analytical framework.The results indicated that the genus Cladocopium exhibited dominance(averaging 82%),followed by Durusdinium(18%)and Breviolum(0.01%)within the examined coral species.Among the 521 Symbiodiniaceae ITS2 sequence types,C15 emerged as the prevalent type(13.24%),trailed by C3u(9.51%)and D1(8.57%).Interestingly,Symbiodiniaceae communities varied among different coral species.Pocillopora damicornis displayed a predominant association with Durusdinium,while Porites lutea,Goniastrea retiformis,Montipora truncata,Montipora aequituberculata,and Acropora divaricata were entirely dominated by the genus Cladocopium(100%),showcasing distinct host specificity.In the cases of Hydnophora exesa,Acropora latistella,Acropora digitifera,and seawater,both Cladocopium and Durusdinium were concurrently detected.Moreover,the diversity of Symbiodiniaceae associated with P.damicornis,P.lutea,G.retiformis,M.truncata,M.aequituberculata,and A.digitifera exhibited significant variations across different seasons.Notably,the results revealed that the alterations in Symbiodiniaceae community compositions were primarily driven by nutrient concentrations and seawater temperature.The network analysis of Symbiodiniaceae revealed the dominant Symbiodiniaceae types C15,C17f,C3u,C3,and D4 were exclusive.This study provided the seasonal variation characteristics of Symbiodiniaceae communities among different coral species,which may be a potential adaptive mechanism to environmental conditions.展开更多
Soil microbiomes are significant for biodiversity,crucial for ecosystem functions,and vital for the health of various organisms.Nevertheless,the impacts of season and plant species shifts on soil microbial diversity a...Soil microbiomes are significant for biodiversity,crucial for ecosystem functions,and vital for the health of various organisms.Nevertheless,the impacts of season and plant species shifts on soil microbial diversity and community assembly are still poorly understood.This study explored soil bacterial,fungal,and protistan communities during summer and winter in a coastal wetland affected by Spartina alterniflora invasion and subsequent Cyperus malaccensis or Kandelia obovata restoration.The results showed that bacterial,fungal,and protistan diversity were 2.63%,40.3%,and 9.90%higher in winter than in summer,respectively.Plant species had a distinct impact on microbial diversity.Notably,K.obovata restoration significantly increased bacterial diversity,but decreased protistan diversity,with no effect on fungal diversity when compared to S.alterniflora invasion.Season and plant species both significantly influenced the community structure of bacteria,fungi,and protists.However,protistan community structure was more sensitive to season compared to the structure of bacterial and fungal communities.The complexity of co-occurrence networks within or among bacteria,fungi,and protists was higher in winter than in summer.Bacterial and protistan community assembly was primarily driven by stochastic processes,while fungal assembly was dominated by deterministic processes.Bacterial and protistan community assembly exhibited lower stochasticity in winter compared to summer,suggesting a more deterministic assembly of communities during winter.Our findings highlight the critical role of season and plant species in regulating microbial communities,revealing higher microbial diversity,network complexity,and determinism in community assembly during winter compared to summer in a subtropical coastal wetland.展开更多
Antarctic krill(Euphausia superba)is a keystone species in the Southern Ocean;however,seasonal variations in reproductive development for krill are complex and remains unknown.A histological investigation with observa...Antarctic krill(Euphausia superba)is a keystone species in the Southern Ocean;however,seasonal variations in reproductive development for krill are complex and remains unknown.A histological investigation with observations of external secondary sex features of krill in the south Scotia Sea region was carried out using a multi-seasonal dataset for detail reproductive descriptions for this commercially important species.The monthly development of secondary sexual characteristics,the thelycum,as well as of oocytes over a period of two years were described.It was observed that krill have diverse reproductive development characteristics within the ovary,and that this function differently between the juvenile,sub-adult,and adult stages.During the summer,adult krill ovaries are large and ripe with oocytes rich in yolk ready for release in late summer.Post spawning,the ovaries resorb,fragment,and regress throughout the autumn and winter.During reproductive diapause period,krill focus on absorbing nutrients.Un-released eggs are reabsorbed by the ovary,the permanent germinal zone is active,and early oocytes begin to develop in preparation for the egg production phase.Krill that are about to spawn have an ovary that fills the space between the digestive gland and muscle.The ovarian development of krill is divided into 10 sexual developmental stages.As a part of this study,data on the carapace thickness with similar development patterns in krill size and carapace width,was investigated for the first time to help understand krill growth and development.展开更多
Seasonal precipitation has always been a key focus of climate prediction.As a dynamic-statistical combined method,the existing observational constraint correction establishes a regression relationship between the nume...Seasonal precipitation has always been a key focus of climate prediction.As a dynamic-statistical combined method,the existing observational constraint correction establishes a regression relationship between the numerical model outputs and historical observations,which can partly predict seasonal precipitation.However,solving a nonlinear problem through linear regression is significantly biased.This study implements a nonlinear optimization of an existing observational constrained correction model using a Light Gradient Boosting Machine(LightGBM)machine learning algorithm based on output from the Beijing National Climate Center Climate System Model(BCC-CSM)and station observations to improve the prediction of summer precipitation in China.The model was trained using a rolling approach,and LightGBM outperformed Linear Regression(LR),Extreme Gradient Boosting(XGBoost),and Categorical Boosting(CatBoost).Using parameter tuning to optimize the machine learning model and predict future summer precipitation using eight different predictors in BCC-CSM,the mean Anomaly Correlation Coefficient(ACC)score in the 2019–22 summer precipitation predictions was 0.17,and the mean Prediction Score(PS)reached 74.The PS score was improved by 7.87%and 6.63%compared with the BCC-CSM and the linear observational constraint approach,respectively.The observational constraint correction prediction strategy with LightGBM significantly and stably improved the prediction of summer precipitation in China compared to the previous linear observational constraint solution,providing a reference for flood control and drought relief during the flood season(summer)in China.展开更多
In the search for new alternatives to control tropical fungal pathogens,the ethanol extracts(EEs)from Acalypha gaumeri(Euphorbiaceae)roots showed antifungal properties against several tropical fungal phytopathogens.A....In the search for new alternatives to control tropical fungal pathogens,the ethanol extracts(EEs)from Acalypha gaumeri(Euphorbiaceae)roots showed antifungal properties against several tropical fungal phytopathogens.A.gaumeri is classified as endemic to the Yucatan Peninsula,Mexico,an area with distinct rainy,drought and northern seasons.The present study evaluated the antifungal activity of threewild populations of A.gaumeri collected quarterly in different seasons during one year against Alternaria chrysanthemi,Colletotrichumgloeosporioides,andPseudocercospora fijiensis and explored their ex-situ propagation.The highest activity was shown by the EE from the Tinum wild population during the rainy season against A.chrysanthemi,C.gloeosporioides,and P.fijiensis with MIC values of 500–1000μg/mL,followed by Yaxcaba populations during the rainy season and Kiuic and Tinum from November against A.chrysanthemi and P.fijiensis 1000 and 500μg/mL,respectively.The propagation of A.gaumeri was more effective throughmediumcuttings,showing 96%with 0.06%auxin indolbutyric acid,whereas only 51%of seeds germinated.The results indicated that seasonal changes and edaphic conditions in the three populations influence the antifungal efficacy of the extracts from A.gaumeri roots.This study enhances the knowledge of the biology and sustainable management of the A.gaumeri plant and advances the development of a biorational product to control tropical fungal diseases.展开更多
Background Ovarian follicular fluid(FF)is a dynamic environment that changes with the seasons,affecting follicle development,ovulation,and oocyte quality.Cells in the follicles release tiny particles called extracellu...Background Ovarian follicular fluid(FF)is a dynamic environment that changes with the seasons,affecting follicle development,ovulation,and oocyte quality.Cells in the follicles release tiny particles called extracellular vesicles(EVs)containing vital regulatory molecules,such as microRNAs(miRNAs).These miRNAs are pivotal in facilitating commu-nication within the follicles through diverse signaling and information transfer forms.EV-coupled miRNA signaling is implicated to be associated with ovarian function,follicle and oocyte growth and response to various environmen-tal insults.Herein,we investigated how seasonal variations directly influence the ovulatory and anovulatory states of ovarian follicles and how are they associated with follicular fluid EV-coupled miRNA dynamics in horses.Results Ultrasonographic monitoring and follicular fluid aspiration of preovulatory follicles in horses during the ano-vulatory(spring:non-breeding)and ovulatory(spring,summer,and fall:breeding)seasons and subsequent EV isola-tion and miRNA profiling identified significant variation in EV-miRNA cargo content.We identified 97 miRNAs with dif-ferential expression among the groups and specific clusters of miRNAs involved in the spring transition(miR-149,-200b,-206,-221,-328,and-615)and peak breeding period(including miR-143,-192,-451,-302b,-100,and let-7c).Bioinformatic analyses showed enrichments in various biological functions,e.g.,transcription factor activity,transcrip-tion and transcription regulation,nucleic acid binding,sequence-specific DNA binding,p53 signaling,and post-trans-lational modifications.Cluster analyses revealed distinct sets of significantly up-and down-regulated miRNAs associ-ated with spring anovulatory(Cluster 1)and summer ovulation–the peak breeding season(Clusters 4 and 6).Conclusions The findings from the current study shed light on the dynamics of FF-EV-coupled miRNAs in relation to equine ovulatory and anovulatory seasons,and their roles in understanding the mechanisms involved in seasonal shifts and ovulation during the breeding season warrant further investigation.展开更多
Forecasting tropical cyclone(TC)activities has been a topic of great interest and research.Taiwan Island(TW)is one of the key regions that is highly exposed to TCs originated from the western North Pacific.Here,the au...Forecasting tropical cyclone(TC)activities has been a topic of great interest and research.Taiwan Island(TW)is one of the key regions that is highly exposed to TCs originated from the western North Pacific.Here,the authors utilize two mainstream reanalysis datasets for the period 1979-2013 and propose an effective statistical seasonal forecasting model-namely,the Sun Yat-sen University(SYSU)Model-for predicting the number of TC landfalls on TW based on the environmental factors in the preseason.The comprehensive predictor sampling and multiple linear regression show that the 850-hPa meridional wind over the west of the Antarctic Peninsula in January,the 300-hPa specific humidity over the open ocean southwest of Australia in January,the 300-hPa relative vorticity over the west of the Sea of Okhotsk in March,and the sea surface temperature in the South Indian Ocean in April,are the most significant predictors.The correlation coefficient between the modeled results and observations reaches 0.87.The model is validated by the leave-one-out and nine-fold cross-validation methods,and recent 9-yr observations(2014-2022).The Antarctic Oscillation,variabilities of the western Pacific subtropical high,Asian summer monsoon,and oceanic tunnel are the possible physical linkages or mechanisms behind the model result.The SYSU Model exhibits a 98%hit rate in 1979-2022(43 out of 44),suggesting an operational potential in the seasonal forecasting of TC landfalls on TW.展开更多
Seasonal variation in phytoplankton composition influences the pathways and efficiency of energy flow,reshaping the structure of the trophic pyramid in the Ross Sea.However,field investigation of grazing processes pre...Seasonal variation in phytoplankton composition influences the pathways and efficiency of energy flow,reshaping the structure of the trophic pyramid in the Ross Sea.However,field investigation of grazing processes presents challenges that hinder our understanding of energy pathways.This study aims to provide insights into energy flow using a three-dimensional ecosystem model applied to the Ross Sea.By analyzing the simulation results,the role of the seasonal phytoplankton succession,specifically the shift from dominance by Phaeocystis antarctica to diatoms,in energy allocation is explored.The short-lived spring bloom of P.antarctica mainly fuels microzooplankton,creating a brief food chain where energy transfers primarily among smaller plankton.In contrast,the subsequent summer bloom of diatoms,which persists longer,provides nearly half of the total phytoplankton energy loss(via ingestion and mortality)to larger mesozooplankton.Our findings indicate that phytoplankton succession in the Ross Sea extends the bloom duration,particularly for diatoms,thereby facilitating energy transfer to higher trophic levels and improving overall energy utilization.This suggests that phytoplankton succession,an ecological strategy adapted to iron-deficient environments in the Ross Sea,explains why the colder region in front of the Ross Ice Shelf is significantly more productive than the northern areas,ultimately favored by top predators.展开更多
Seasonal prediction of summer rainfall in China plays a crucial role in decision-making,environmental protection,and socio-economic development,while it currently has a low prediction skill.We developed a deep learnin...Seasonal prediction of summer rainfall in China plays a crucial role in decision-making,environmental protection,and socio-economic development,while it currently has a low prediction skill.We developed a deep learning-based seasonal prediction bias correction method for summer rainfall in China.Based on prediction fields from the flexible Global Ocean-Atmosphere-Land System Model finite volume version 2(FGOALS-f2),we optimized the loss function of U-Net,trained with different hyperparameters,and selected the optimum model.U-Net model can extract multi-scale feature information and preserve spatial information,making it suitable for processing meteorological data.With this endto-end model,the precipitation distribution can be obtained directly without using the traditional method of data dimensionality reduction(e.g.,Empirical Orthogonal Function),which could maximize the retention of spatio-temporal information of the input data.Optimization of the loss function enhances the prediction results and mitigates model overfitting.The independent prediction shows a significant skill improvement measured by the anomalous correlation coefficient score.The skill has an average value of 0.679 in China(0°–63°N,73°–133°E)and 0.691 in the region of the Chinese mainland,which significantly improves the dynamical prediction skill by 1357%and 4836%.This study suggests that the deep learning(U-Net)-based seasonal prediction bias correction method is a promising approach for improving rainfall prediction of the dynamical model.展开更多
The phenomenon of'bamboo-like'thin interlayers developed in rock salt is one of the most prominent features of Paleogene salt-bearing strata in eastern China,where centimeter-thick rock salts appear separately...The phenomenon of'bamboo-like'thin interlayers developed in rock salt is one of the most prominent features of Paleogene salt-bearing strata in eastern China,where centimeter-thick rock salts appear separately,forming rhythmic units.At present,detailed analyses of these rhythms of rock salt are still limited,which directly affects the achievement of comprehensive and in-depth understanding of the developmental laws pertaining to this kind of saline lake.Therefore,we selected the typical rhythmic'bamboo-like'rock salts of the Shizhai Depression in Jiangsu Province as the research subject.Through careful observation of rock salts in hand samples and detailed petrographic and mineralogical analyses,we analyzed the hydrogen and oxygen isotopic compositions,homogenization temperatures and chemical compositions of individual fluid inclusions in halite crystals.Early-stage rhythmic deposition was a product of continental saline lake evolution in winter or spring,late-stage rhythmic deposition being the product of evolution in the summer.The seasonal evolution of the halite sequences was determined and two brine enrichment events were identified.In addition,the quiet saline lake environment with concentrated brine represented by rock salt was more likely to precipitate potassium.This study provides a new reference for the evolution of both Paleogene climate and saline lakes in eastern China.展开更多
Animal coloration has a wide range of biological functions and may be subject to different,sometimes conficting,selective pressures.In crustaceans,the evolution of coloration is relatively unstudied,despite the broad ...Animal coloration has a wide range of biological functions and may be subject to different,sometimes conficting,selective pressures.In crustaceans,the evolution of coloration is relatively unstudied,despite the broad range of colors and color patterns,which includes variability at multiple levels.Freshwater crayfsh are known to show color variability within species and populations,as well as intra-individual variability,but thefunction,if any,of crayfsh coloration is largely unknown.Here,I report on an experiment to understand patterns of color variability in the crayfsh Faxonius virilis and show that variation is strongly correlated to ontogenetic changes from a summer non-reproductive form to a fall reproductiveform.Crayfsh showed comparatively little inter-and intra-individual color variation in their non-reproductive form,but substantial variation at bothlevels in the reproductive form.Transition to the reproductive form was associated with the development of greener or bluer coloration localizedto the chelae on a subset of individuals,but these changes showed no clear correlation with sex or body size.Future investigations should focuson determining whether differences in color between individuals in the mating season are associated with any physiological or behavioral differences,or with differential susceptibility to predation.展开更多
基金The Science and Technology Basic Resources Survey Project,No.2021FY101002Wetland Protection and Restoration in China Funded by the Palson Institute and Laoniu Foundation,UNDP-GEF Flyway Project,No.PIMS ID:6110。
文摘Effective conservation relies on robust assessments;however,the lack of waterbird data in the Yellow River Basin(YRB)has led to an underestimation of key habitat significance.This study addressed this gap by evaluating YRB wetland conservation importance using waterbirds as indicators and applying Ramsar,Important Bird Areas(IBA),and East Asian-Australasian Flyway(EAAF)criteria.We integrated coordinated surveys with citizen science data,creating a framework that tackles data deficiencies along the under-monitored Central Asian Flyway(CAF).Our analysis identified 75 priority wetlands,supporting 15 threatened species and 49 exceeding global/flyway 1%thresholds,highlighting the basin's biodiversity.We observed strong seasonal habitat use,with high-altitude wetlands vital for breeding and migration,and the Yellow River Delta providing year-round refuge.This research also provided data to refine Baer's Pochard population estimates.Alarmingly,one-third of the identified priority areas,primarily rivers and lakes,remain unprotected.To address this,we recommend systematic surveys,enhanced protected areas,OECMs,and targeted wetland restoration.This study underscores the YRB's role in regional conservation and provides essential data for adaptive management,particularly emphasizing the CAF's importance.
基金supported by the Australian Research Council(Grant No.CE230100012)。
文摘The onset,cessation,and length of the rainy season are crucial for global water resources,agricultural practices,and food security.However,the response of precipitation seasonality to global warming remains uncertain.In this study,we analyze how global warming levels(GWLs)of 1.5℃ and 2℃ could affect the timing of rainfall onset(RODs),rainfall cessation(RCDs),and the overall duration of the rainy season(LRS)over global land monsoon(GLM)regions using simulations from CMIP6 under the SSP2-4.5 and SSP5-8.5 scenarios.With high model consensus,our results reveal that RODs are projected to occur later over Southern Africa,North Africa,and South America,but earlier over South Asia and Australia,in a warmer climate.The projected early RODs in Australia are more pronounced at the 2℃ GWL under SSP5-8.5.On the other hand,early RCDs are projected over South America and East Asia,while late RCDs are projected over North Africa,with high inter-model agreement.These changes are associated with a future decrease in LRS in most GLM regions.Additionally,we found that continuous warming over 1.5℃ will further reduce the length of the rainy season,especially over the South America,North Africa,and Southern Africa monsoon regions.The findings underscore the urgent need to mitigate global warming.
基金Under the auspices of the National Key Research and Development Program of China(No.2019YFA0606603)。
文摘Fire season affects the dynamic changes of post-fire vegetation communities and carbon emissions.Analyzing its global patterns supports understanding of the ecological impacts of fires and responses of fires to climate change.Meteorological variables have been widely used to quantify fire season in current studies.However,their results can not be used to assess climate impacts on the seasonality of fire activities.Here we utilized satellite-based Moderate Resolution Imaging Spectroradiometer(MODIS)burned area data from 2001 to 2022 to identify global fire season types based on the number of peaks within a year.Using satellite data and innovatively processing the data to obtain a more accurate length of the fire season.We divided fire season types and examined the spatial distribution of fire season types across the Koppen-Geiger climate(KGC)zones.At a global scale,we identified three major fire season types,including unimodal(31.25%),bimodal(52.07%),and random(16.69%).The unimodal fire season primarily occurs in boreal and tropical regions lasting about 2.7 mon.In comparison,temperate ecosystems tend to have a longer fire season(3 mon)with two peaks throughout the year.The KGC zones show divergent contributions from the fire season types,indicating potential impacts of the climatic conditions on fire seasonality in these regions.
基金the W.M.Keck Center for Nano-Scale Imaging in the Department of Chemistry and Biochemistry at the University of Arizona(Grant No.RRID:SCR_022884),with funding from the W.M.Keck Foundation Grant.
文摘Approximately 3.44 billion tons of copper mine tailings(MT)were produced globally in 2018 with an increase of 45%from 2010.Significant efforts are being made to manage these tailings through storage facilities,recycling,and reuse in different industries.Currently,a large portion of tailings are managed through the tailing storage facilities(TSF)where these tailings undergo hydro-thermal-mechanical stresses with seasonal cycles which are not comprehensively understood.This study presents an investigative study to evaluate the performance of control and cement-stabilized copper MT under the influence of seasonal cycles,freeze-thaw(F-T)and wet-dry(W-D)conditions,representing the seasonal variability in the cold and arid regions.The control and cement-stabilized MT samples were subjected to a maximum of 12 F-T and 12 W-D cycles and corresponding micro-and-macro behavior was investigated through scanning electron microscope(SEM),volumetric strain(εvT,wet density(r),moisture content loss,and unconfined compressive strength(UCS)tests.The results indicated the vulnerability of Copper MT to 67%and 75%strength loss reaching residual states with 12 F-T and 8 W-D cycles,respectively.Whereas the stabilized MT retained 39%-55%and 16%-34%strength with F-T and W-D cycles,demonstrating increased durability.This research highlights the impact of seasonal cycles and corresponding strength-deformation characteristics of control and stabilized Copper MT in cold and arid regions.
基金an MSc thesis research grant from the Zoological Society of London(ZSL)Nepal.RCK’s effort was supported in part by the Office of Research Infrastructure Programs(ORIP)of the National Institutes of Health through grant number P51OD010425 to the Washington National Primate Research Center,USA。
文摘The Himalayan monal(Lophophorus impejanus),Nepal’s national bird,is a protected species facing significant conservation challenges.Understanding the distribution and habitat preferences of the Himalayan monal(HM)is crucial for its conservation.This study was conducted in the Langtang National Park(LNP),Nepal using the route census method during both winter(November/December 2022)and summer(June 2023)seasons to examine the seasonal variation in HM’s elevational distribution and habitat preference.Further,we assessed their conservation threats by conducting a semi-structured questionnaire survey with the local residents.During the winter period,the HMs preferred grassland habitats,while in the summer,their preference shifted to shrubland and barren area.HM abundance was negatively associated with the Normalized Differential Vegetation Index(NDVI)and the shortest distance from the survey trails in the winter.The HMs actively avoided areas with high anthropogenic pressure.In the summer,they showed a wider elevational range up to 4400 m above sea level(a.s.l.),with a higher sighting frequency between 3600 and 3900 m a.s.l.The questionnaire survey of the local residents revealed that anthropogenic pressure such as poaching and free-ranging livestock grazing are the major threats to the species in the study area.This study provides valuable insight into the complex habitat preferences and critical threats faced by the HMs in LNP and underscores the urgent need for targeted conservation action.
基金supported by the National Natural Science Foundation of China(Nos.42030707,72394404)the International Partnership Program of the Chinese Academy of Sciences(No.121311KYSB20190029)the Fundamental Research Fund for the Central Universities(Nos.20720210083,20720210082).
文摘Halocarbons play a vital role in ozone depletion and global warming,and are regulated by the Montreal Protocol(MP)and its amendments.China has been identified as an important contributor to the halocarbon emissions,but the regional sources of halocarbons in China are not yet well comprehended.To investigate the characteristics,emissions,and source profiles,this study conducted a field campaign in Xiamen,a coastal city in southeastern China.Higher enhancements were found in the unregulated halocarbons(CH_(3)Cl,CH_(2)Cl_(2),CHCl_(3))than in the MP eliminated species(CCl_(4),CH_(3)Br)and theMP controlled species(HCFCs,HFCs).Many of the measured halocarbons varied seasonally and regionally,depending on the anthropogenic sources and atmospheric transport.Backward trajectory analysis showed that the air masses from inland were polluted over Shandong,Hebei,and northern Fujian in the cold season,while the air masses fromthe sea in the warm season were clean.Different air masses in two seasons were associated with the halocarbon patterns in the study area.Industrial activities,especially solvent usage,were the primary sources of halocarbons.The emission hot spots in Fujian Province were concentrated in Sanming,Fuzhou,and Xiamen,and the unregulated halocarbons made the largest contribution.This study provides an insight for a deep understanding of the characteristics and potential sources of halocarbons,and for strengthened management of halocarbons in China.
基金supported by the Southwest Minzu University Research Startup Funds (No.16011221038,RQD2022021)Double World-Class Project (No.CX2023010)。
文摘Wetland degradation is an escalating global challenge with profound impacts on animal diversity,particularly during successional processes.Birds,as highly mobile and environmentally sensitive organisms,serve as effective indicators of ecological change.While previous studies have primarily focused on local community structures and species diversity during a specific season,there is a need to extend the research timeframe and explore broader spatial variations.Additionally,expanding from simple species diversity indices to more multidimensional diversity indices would provide a more comprehensive understanding of wetland health and resilience.To address these gaps,we investigated the effects of wetland degradation on bird diversity across taxonomic,phylogenetic,and functional dimensions in the Zoige Wetland,a plateau meadow wetland biodiversity hotspot.Surveys were conducted during both breeding(summer)and overwintering(winter)seasons across 20 transects in 5 sampling areas,representing 4 degradation levels(pristine,low,medium,and high).Our study recorded a total of 106 bird species from 32 families and 14 orders,revealing distinct seasonal patterns in bird community composition and diversity.Biodiversity indices were significantly higher in pristine and low-degraded wetlands,particularly benefiting waterfowl(Anseriformes,Ciconiiformes)and wading birds(Charadriiformes)in winter,when these areas provided superior food resources and habitat conditions.In contrast,medium and highly degraded wetlands supported increased numbers of terrestrial birds(Passeriformes)and raptors(Accipitriformes,Falconiformes).Seasonal differences in taxonomic,phylogenetic,and functional diversity indices highlighted the contrasting ecological roles of wetlands during breeding and overwintering periods.Furthermore,indicator species analysis revealed key species associated with specific degradation levels and seasons,providing valuable insights into wetland health.This study underscores the importance of spatiotemporal dynamics in understanding avian responses to wetland degradation.By linking seasonal patterns of bird diversity to habitat conditions,our findings contribute to conservation efforts and provide a framework for assessing wetland degradation and its ecological impacts.
基金supported by the National Natural Science Foundation of China [grant number 42030605]the National Key R&D Program of China [grant number 2020YFA0608004]。
文摘A remarkable marine heatwave,known as the“Blob”,occurred in the Northeast Pacific Ocean from late 2013 to early 2016,which displayed strong warm anomalies extending from the surface to a depth of 300 m.This study employed two assimilation schemes based on the global Climate Forecast System of Nanjing University of Information Science(NUIST-CFS 1.0)to investigate the impact of ocean data assimilation on the seasonal prediction of this extreme marine heatwave.The sea surface temperature(SST)nudging scheme assimilates SST only,while the deterministic ensemble Kalman filter(EnKF)scheme assimilates observations from the surface to the deep ocean.The latter notably improves the forecasting skill for subsurface temperature anomalies,especially at the depth of 100-300 m(the lower layer),outperforming the SST nudging scheme.It excels in predicting both horizontal and vertical heat transport in the lower layer,contributing to improved forecasts of the lower-layer warming during the Blob.These improvements stem from the assimilation of subsurface observational data,which are important in predicting the upper-ocean conditions.The results suggest that assimilating ocean data with the EnKF scheme significantly enhances the accuracy in predicting subsurface temperature anomalies during the Blob and offers better understanding of its underlying mechanisms.
文摘The symbiotic association between reef-building corals and Symbiodiniaceae is pivotal for coral reef ecosystems,yet remains susceptible to environmental factors.Currently,there is a dearth of research examining seasonal fluctuations in coral-associated Symbiodiniaceae communities.In this study,we investigated the seasonal dynamics of Symbiodiniaceae communities associated with coral species in the Luhuitou coral reef using high-throughput sequencing techniques and SymPortal analytical framework.The results indicated that the genus Cladocopium exhibited dominance(averaging 82%),followed by Durusdinium(18%)and Breviolum(0.01%)within the examined coral species.Among the 521 Symbiodiniaceae ITS2 sequence types,C15 emerged as the prevalent type(13.24%),trailed by C3u(9.51%)and D1(8.57%).Interestingly,Symbiodiniaceae communities varied among different coral species.Pocillopora damicornis displayed a predominant association with Durusdinium,while Porites lutea,Goniastrea retiformis,Montipora truncata,Montipora aequituberculata,and Acropora divaricata were entirely dominated by the genus Cladocopium(100%),showcasing distinct host specificity.In the cases of Hydnophora exesa,Acropora latistella,Acropora digitifera,and seawater,both Cladocopium and Durusdinium were concurrently detected.Moreover,the diversity of Symbiodiniaceae associated with P.damicornis,P.lutea,G.retiformis,M.truncata,M.aequituberculata,and A.digitifera exhibited significant variations across different seasons.Notably,the results revealed that the alterations in Symbiodiniaceae community compositions were primarily driven by nutrient concentrations and seawater temperature.The network analysis of Symbiodiniaceae revealed the dominant Symbiodiniaceae types C15,C17f,C3u,C3,and D4 were exclusive.This study provided the seasonal variation characteristics of Symbiodiniaceae communities among different coral species,which may be a potential adaptive mechanism to environmental conditions.
基金supported by the Natural Resources Science and Technology Innovation Project of Fujian Province,China(No.KY-090000-04-2022-012)the National Natural Science Foundation of China(Nos.42077041 and 42377301)+1 种基金the National Natural Science Foundation of Fujian Province,China(No.2021J011038)the Talent Introduction Program of Minjiang University,China(No.MJY20012).
文摘Soil microbiomes are significant for biodiversity,crucial for ecosystem functions,and vital for the health of various organisms.Nevertheless,the impacts of season and plant species shifts on soil microbial diversity and community assembly are still poorly understood.This study explored soil bacterial,fungal,and protistan communities during summer and winter in a coastal wetland affected by Spartina alterniflora invasion and subsequent Cyperus malaccensis or Kandelia obovata restoration.The results showed that bacterial,fungal,and protistan diversity were 2.63%,40.3%,and 9.90%higher in winter than in summer,respectively.Plant species had a distinct impact on microbial diversity.Notably,K.obovata restoration significantly increased bacterial diversity,but decreased protistan diversity,with no effect on fungal diversity when compared to S.alterniflora invasion.Season and plant species both significantly influenced the community structure of bacteria,fungi,and protists.However,protistan community structure was more sensitive to season compared to the structure of bacterial and fungal communities.The complexity of co-occurrence networks within or among bacteria,fungi,and protists was higher in winter than in summer.Bacterial and protistan community assembly was primarily driven by stochastic processes,while fungal assembly was dominated by deterministic processes.Bacterial and protistan community assembly exhibited lower stochasticity in winter compared to summer,suggesting a more deterministic assembly of communities during winter.Our findings highlight the critical role of season and plant species in regulating microbial communities,revealing higher microbial diversity,network complexity,and determinism in community assembly during winter compared to summer in a subtropical coastal wetland.
基金Supported by the Inter-governmental Science and Technology Innovation(STI)Cooperation Special Program of the National Key Research and Development Program of China(No.2023YFE0104500)the NIWA-SHOU-Otago Joint Research Center on Antarctic Marine Science。
文摘Antarctic krill(Euphausia superba)is a keystone species in the Southern Ocean;however,seasonal variations in reproductive development for krill are complex and remains unknown.A histological investigation with observations of external secondary sex features of krill in the south Scotia Sea region was carried out using a multi-seasonal dataset for detail reproductive descriptions for this commercially important species.The monthly development of secondary sexual characteristics,the thelycum,as well as of oocytes over a period of two years were described.It was observed that krill have diverse reproductive development characteristics within the ovary,and that this function differently between the juvenile,sub-adult,and adult stages.During the summer,adult krill ovaries are large and ripe with oocytes rich in yolk ready for release in late summer.Post spawning,the ovaries resorb,fragment,and regress throughout the autumn and winter.During reproductive diapause period,krill focus on absorbing nutrients.Un-released eggs are reabsorbed by the ovary,the permanent germinal zone is active,and early oocytes begin to develop in preparation for the egg production phase.Krill that are about to spawn have an ovary that fills the space between the digestive gland and muscle.The ovarian development of krill is divided into 10 sexual developmental stages.As a part of this study,data on the carapace thickness with similar development patterns in krill size and carapace width,was investigated for the first time to help understand krill growth and development.
基金jointly supported by the National Natural Science Foundation of China(Grant Nos.42122034,42075043,42330609)the Second Tibetan Plateau Scientific Expedition and Research program(2019QZKK0103)+2 种基金Key Talent Project in Gansu and Central Guidance Fund for Local Science and Technology Development Projects in Gansu(No.24ZYQA031)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2021427)West Light Foundation of the Chinese Academy of Sciences(xbzg-zdsys-202215)。
文摘Seasonal precipitation has always been a key focus of climate prediction.As a dynamic-statistical combined method,the existing observational constraint correction establishes a regression relationship between the numerical model outputs and historical observations,which can partly predict seasonal precipitation.However,solving a nonlinear problem through linear regression is significantly biased.This study implements a nonlinear optimization of an existing observational constrained correction model using a Light Gradient Boosting Machine(LightGBM)machine learning algorithm based on output from the Beijing National Climate Center Climate System Model(BCC-CSM)and station observations to improve the prediction of summer precipitation in China.The model was trained using a rolling approach,and LightGBM outperformed Linear Regression(LR),Extreme Gradient Boosting(XGBoost),and Categorical Boosting(CatBoost).Using parameter tuning to optimize the machine learning model and predict future summer precipitation using eight different predictors in BCC-CSM,the mean Anomaly Correlation Coefficient(ACC)score in the 2019–22 summer precipitation predictions was 0.17,and the mean Prediction Score(PS)reached 74.The PS score was improved by 7.87%and 6.63%compared with the BCC-CSM and the linear observational constraint approach,respectively.The observational constraint correction prediction strategy with LightGBM significantly and stably improved the prediction of summer precipitation in China compared to the previous linear observational constraint solution,providing a reference for flood control and drought relief during the flood season(summer)in China.
基金supported by Secihti project PDCPN-2015-266,Mexico.
文摘In the search for new alternatives to control tropical fungal pathogens,the ethanol extracts(EEs)from Acalypha gaumeri(Euphorbiaceae)roots showed antifungal properties against several tropical fungal phytopathogens.A.gaumeri is classified as endemic to the Yucatan Peninsula,Mexico,an area with distinct rainy,drought and northern seasons.The present study evaluated the antifungal activity of threewild populations of A.gaumeri collected quarterly in different seasons during one year against Alternaria chrysanthemi,Colletotrichumgloeosporioides,andPseudocercospora fijiensis and explored their ex-situ propagation.The highest activity was shown by the EE from the Tinum wild population during the rainy season against A.chrysanthemi,C.gloeosporioides,and P.fijiensis with MIC values of 500–1000μg/mL,followed by Yaxcaba populations during the rainy season and Kiuic and Tinum from November against A.chrysanthemi and P.fijiensis 1000 and 500μg/mL,respectively.The propagation of A.gaumeri was more effective throughmediumcuttings,showing 96%with 0.06%auxin indolbutyric acid,whereas only 51%of seeds germinated.The results indicated that seasonal changes and edaphic conditions in the three populations influence the antifungal efficacy of the extracts from A.gaumeri roots.This study enhances the knowledge of the biology and sustainable management of the A.gaumeri plant and advances the development of a biorational product to control tropical fungal diseases.
基金Southern Illinois University,Carbondale,ILMinistry of Higher Education&Scientific Research,Baghdad,Iraq+2 种基金NIFA-USDA Hatch project accession#1016077(Multistate#W4171)USDAARS project 6066-31000-015-00DNIH MS-IDeA network of Biomedical Research Excellence award 5P20GMI03476-19.GMI received a PhD scholarship from the Ministry of Higher Education&Scientific Research,Baghdad,Iraq.
文摘Background Ovarian follicular fluid(FF)is a dynamic environment that changes with the seasons,affecting follicle development,ovulation,and oocyte quality.Cells in the follicles release tiny particles called extracellular vesicles(EVs)containing vital regulatory molecules,such as microRNAs(miRNAs).These miRNAs are pivotal in facilitating commu-nication within the follicles through diverse signaling and information transfer forms.EV-coupled miRNA signaling is implicated to be associated with ovarian function,follicle and oocyte growth and response to various environmen-tal insults.Herein,we investigated how seasonal variations directly influence the ovulatory and anovulatory states of ovarian follicles and how are they associated with follicular fluid EV-coupled miRNA dynamics in horses.Results Ultrasonographic monitoring and follicular fluid aspiration of preovulatory follicles in horses during the ano-vulatory(spring:non-breeding)and ovulatory(spring,summer,and fall:breeding)seasons and subsequent EV isola-tion and miRNA profiling identified significant variation in EV-miRNA cargo content.We identified 97 miRNAs with dif-ferential expression among the groups and specific clusters of miRNAs involved in the spring transition(miR-149,-200b,-206,-221,-328,and-615)and peak breeding period(including miR-143,-192,-451,-302b,-100,and let-7c).Bioinformatic analyses showed enrichments in various biological functions,e.g.,transcription factor activity,transcrip-tion and transcription regulation,nucleic acid binding,sequence-specific DNA binding,p53 signaling,and post-trans-lational modifications.Cluster analyses revealed distinct sets of significantly up-and down-regulated miRNAs associ-ated with spring anovulatory(Cluster 1)and summer ovulation–the peak breeding season(Clusters 4 and 6).Conclusions The findings from the current study shed light on the dynamics of FF-EV-coupled miRNAs in relation to equine ovulatory and anovulatory seasons,and their roles in understanding the mechanisms involved in seasonal shifts and ovulation during the breeding season warrant further investigation.
基金jointly supported by the Innovation Group Project of the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)[grant number 316323005]the Guangdong Basic and Applied Basic Research Foundation[grant numbers 2023A1515010741 and 2024B1515020035]the Science and Technology Planning Project of Guangdong Province[grant number 2023B1212060019]。
文摘Forecasting tropical cyclone(TC)activities has been a topic of great interest and research.Taiwan Island(TW)is one of the key regions that is highly exposed to TCs originated from the western North Pacific.Here,the authors utilize two mainstream reanalysis datasets for the period 1979-2013 and propose an effective statistical seasonal forecasting model-namely,the Sun Yat-sen University(SYSU)Model-for predicting the number of TC landfalls on TW based on the environmental factors in the preseason.The comprehensive predictor sampling and multiple linear regression show that the 850-hPa meridional wind over the west of the Antarctic Peninsula in January,the 300-hPa specific humidity over the open ocean southwest of Australia in January,the 300-hPa relative vorticity over the west of the Sea of Okhotsk in March,and the sea surface temperature in the South Indian Ocean in April,are the most significant predictors.The correlation coefficient between the modeled results and observations reaches 0.87.The model is validated by the leave-one-out and nine-fold cross-validation methods,and recent 9-yr observations(2014-2022).The Antarctic Oscillation,variabilities of the western Pacific subtropical high,Asian summer monsoon,and oceanic tunnel are the possible physical linkages or mechanisms behind the model result.The SYSU Model exhibits a 98%hit rate in 1979-2022(43 out of 44),suggesting an operational potential in the seasonal forecasting of TC landfalls on TW.
基金The National Natural Science Foundation of China under contract No.41941008the National Key Research and Development Program of China under contract No.2023YFC3107702.
文摘Seasonal variation in phytoplankton composition influences the pathways and efficiency of energy flow,reshaping the structure of the trophic pyramid in the Ross Sea.However,field investigation of grazing processes presents challenges that hinder our understanding of energy pathways.This study aims to provide insights into energy flow using a three-dimensional ecosystem model applied to the Ross Sea.By analyzing the simulation results,the role of the seasonal phytoplankton succession,specifically the shift from dominance by Phaeocystis antarctica to diatoms,in energy allocation is explored.The short-lived spring bloom of P.antarctica mainly fuels microzooplankton,creating a brief food chain where energy transfers primarily among smaller plankton.In contrast,the subsequent summer bloom of diatoms,which persists longer,provides nearly half of the total phytoplankton energy loss(via ingestion and mortality)to larger mesozooplankton.Our findings indicate that phytoplankton succession in the Ross Sea extends the bloom duration,particularly for diatoms,thereby facilitating energy transfer to higher trophic levels and improving overall energy utilization.This suggests that phytoplankton succession,an ecological strategy adapted to iron-deficient environments in the Ross Sea,explains why the colder region in front of the Ross Ice Shelf is significantly more productive than the northern areas,ultimately favored by top predators.
基金Guangdong Major Project of Basic and Applied Basic Research(2020B0301030004)Postdoctoral Fellowship Program of CPSF(GZC20232598)+1 种基金China Postdoctoral Science Foundation(2024M753168)National Key Scientific and Technological Infrastructure Project“Earth System Numerical Simulation Facility”(EarthLab)。
文摘Seasonal prediction of summer rainfall in China plays a crucial role in decision-making,environmental protection,and socio-economic development,while it currently has a low prediction skill.We developed a deep learning-based seasonal prediction bias correction method for summer rainfall in China.Based on prediction fields from the flexible Global Ocean-Atmosphere-Land System Model finite volume version 2(FGOALS-f2),we optimized the loss function of U-Net,trained with different hyperparameters,and selected the optimum model.U-Net model can extract multi-scale feature information and preserve spatial information,making it suitable for processing meteorological data.With this endto-end model,the precipitation distribution can be obtained directly without using the traditional method of data dimensionality reduction(e.g.,Empirical Orthogonal Function),which could maximize the retention of spatio-temporal information of the input data.Optimization of the loss function enhances the prediction results and mitigates model overfitting.The independent prediction shows a significant skill improvement measured by the anomalous correlation coefficient score.The skill has an average value of 0.679 in China(0°–63°N,73°–133°E)and 0.691 in the region of the Chinese mainland,which significantly improves the dynamical prediction skill by 1357%and 4836%.This study suggests that the deep learning(U-Net)-based seasonal prediction bias correction method is a promising approach for improving rainfall prediction of the dynamical model.
基金supported by the Natural Science Foundation of Jiangxi Province,China(Grant No.20242BAB20130)the Basic Research Funds Program of the Chinese Academy of Geological Sciences(Grant No.YYWF201607)the National Natural Science Foundation of China(Grant No.41902064)。
文摘The phenomenon of'bamboo-like'thin interlayers developed in rock salt is one of the most prominent features of Paleogene salt-bearing strata in eastern China,where centimeter-thick rock salts appear separately,forming rhythmic units.At present,detailed analyses of these rhythms of rock salt are still limited,which directly affects the achievement of comprehensive and in-depth understanding of the developmental laws pertaining to this kind of saline lake.Therefore,we selected the typical rhythmic'bamboo-like'rock salts of the Shizhai Depression in Jiangsu Province as the research subject.Through careful observation of rock salts in hand samples and detailed petrographic and mineralogical analyses,we analyzed the hydrogen and oxygen isotopic compositions,homogenization temperatures and chemical compositions of individual fluid inclusions in halite crystals.Early-stage rhythmic deposition was a product of continental saline lake evolution in winter or spring,late-stage rhythmic deposition being the product of evolution in the summer.The seasonal evolution of the halite sequences was determined and two brine enrichment events were identified.In addition,the quiet saline lake environment with concentrated brine represented by rock salt was more likely to precipitate potassium.This study provides a new reference for the evolution of both Paleogene climate and saline lakes in eastern China.
文摘Animal coloration has a wide range of biological functions and may be subject to different,sometimes conficting,selective pressures.In crustaceans,the evolution of coloration is relatively unstudied,despite the broad range of colors and color patterns,which includes variability at multiple levels.Freshwater crayfsh are known to show color variability within species and populations,as well as intra-individual variability,but thefunction,if any,of crayfsh coloration is largely unknown.Here,I report on an experiment to understand patterns of color variability in the crayfsh Faxonius virilis and show that variation is strongly correlated to ontogenetic changes from a summer non-reproductive form to a fall reproductiveform.Crayfsh showed comparatively little inter-and intra-individual color variation in their non-reproductive form,but substantial variation at bothlevels in the reproductive form.Transition to the reproductive form was associated with the development of greener or bluer coloration localizedto the chelae on a subset of individuals,but these changes showed no clear correlation with sex or body size.Future investigations should focuson determining whether differences in color between individuals in the mating season are associated with any physiological or behavioral differences,or with differential susceptibility to predation.
