To investigate the application effects of anisodamine in the immersion vaccination of Larimichthys crocea,the inactivated Pseudomonas plecoglossicida vaccine with anisodamine adjuvant was used for the immersion vaccination of large yellow croaker.The results showed that serum antibody levels significantly increased in both the adjuvant-free vaccine group(FKC group)and the anisodamine-supplemented vaccine group(FKCA group)during weeks 1～4 post-immunization.Notably,the FKCA group exhibited significantly elevated serum antibody levels compared with the FKC group at weeks 2～3.The results of RT-PCR indicated that immune-related genes(IgM,IL-1β,MHC-Ⅰα,MHC-Ⅱβ,CD4,and CD8)showed upregulated expression in head kidney and spleen tissues from day 4 post-immunization.Specifically,peak expression levels of IgM,IL-1β,MHC-Ⅰα,and CD8 in the head kidney were significantly higher in the FKCA group than in the FKC group.Enzyme activity assays showed that the activities of AKP and ACP in epidermal mucus reached their peaks on day 7 after immunization,while the activities of AKP and ACP in the serum reached their peaks on days 4 and 14 respectively.The AKP activity of FKCA group was significantly higher than that of FKC group.Histological examination revealed that both vaccinated groups exhibited dermal thickening and increased mucus cell density in skin tissues on day 4 post-immunization,with the FKCA group additionally demonstrating significant widening of primary gill filaments and more pronounced physiological alterations.At 28 days post-immunization,the FKCA group reached a relative protection rate of 61％post challenge,which was significantly higher than that of the FKC group(14％).Growth index analysis revealed that there were no significant differences in the average weight gain rate or specific growth rate between the vaccine group and the control group during the immunization period.As above,the research indicates that anisodamine,as an immersion vaccine adjuvant,can significantly increase the relative protection rate of the inactivated P.plecoglossicida vaccine for L.crocea,improve the serum antibody level and the relative expression level of immune genes in the head kidney,enhance the activities of AKP and ACP,and strengthen the physiological expansion responses of the skin and gill filaments to immersion immunization,without compromising growth performance.These findings highlight anisodamine as a promising adjuvant candidate for immersion vaccination in L.crocea.
A total of 156 sedimentary diatom specimens from D3-5 gravity cored sample(316 cm long)in the Powell Basin(62.2322°S,50.3449°W;water depth 3 397 m)in Antarctic during the China's 28th Antarctic Scientific Expedition from 2011 to 2012 were analyzed,from which 54 species and variants of diatoms were identified and they were dominated by marine and cold-water species.The following stages of the changes of the Powell Basin marine environment since the Late Pleistocene were established based on diatom analysis.During the 58.6～72.5 ka BP period,diatoms were dominated by cold-water and sea-ice species,and coastal species appeared.It was inferred that due to the growth of the Antarctic ice sheet,the Powell Basin was under the control of polar cold-water mass,with distinct cold-warm alternations in climate.Besides,the sea level was low and the water depth was shallow.During the 40.7～58.6 ka BP period,there was an obvious climate cold-warm change.The marine environment was greatly affected by climate change and becomes unstable.It was inferred that due to the melting of sea ice,the strengthening of thermohaline circulation,and the frequent occurrence of ice-rafted debris events,the species and abundance of diatoms decreased sharply.In the 26.2～40.7 ka BP period,the diatom species increased significantly,and the sea-ice appeared and cold-water species increased.It was speculated that in the early stage of ice-sheet growth of the Last Glacial Period,the influence range of the mid-latitude warm water mass in the Antarctic Sea area expanded southwards,and the cold and warm water masses were strongly mixed to drive the thermohaline circulation.From 26.2 ka BP to the present,the abundance of diatoms increased with the occurrence of diatom species Fragilariopsis oceanica indicating mixed with polar cold and warm water,suggesting that the mix of surface and bottom water in the study area was enhanced.Besides,the sea ice coverage area continued to expand,the Weddell Circulation was strengthened,while the influence of mid-latitude warm water was weakened.Overall,the Powell Basin underwent a transition from the cold period(development of the Antarctic Ice Sheet)to the warm period,and then to the cold period(the Last Glacial Period)since the Late Pleistocene,and there was a long period of ice-rafted debris events in the MIS 3 stage.
Mesoscale oceanic eddies are critically important phenomena in the ocean.The sea surface temperature anomalies they induce can alter the heat fluxes at the air-sea interface,subsequently affecting the marine atmospheric boundary layer and the free atmosphere,thereby exerting influences on both local and global climates.Therefore,based on observational and reanalysis data,spatiotemporal filtering and dynamical compositing methods were employed to examine the modulation of air-sea heat exchange by mesoscale eddies in the tropical Northwest Pacific from 1993 to 2019.Results indicate that anticyclonic(cyclonic)eddies are associated with warm(cold)sea surface temperature(SST)anomalies,which lead to an increase(decrease)in the air-sea temperature gradient,thereby enhancing(reducing)evaporation and subsequently increasing(decreasing)the heat flux from the ocean to the atmosphere.These anomalies in air-sea variables decrease gradually outward from the eddy center,following an exponential Gaussian-like distribution.SST anomalies induced by mesoscale eddies are identified as the primary driver of variations in the air-sea temperature gradient,evaporation rate,and heat flux.For anticyclonic eddies,the linear regression coefficients between SST anomalies and anomalies in the air-sea temperature gradient,evaporation rate,sensible heat flux,and latent heat flux are 0.91,48.2 cm/(a·℃),11.6 W/(m2·℃),38.3 W/(m2·℃),respectively.For cyclonic eddies,the corresponding coefficients are 0.77,37.5 cm/(a·℃),10.0 W/(m2·℃),36.8 W/(m2·℃).The analysis suggests that anticyclonic eddies exert a more pronounced influence on the atmosphere compared to cyclonic eddies,a finding that contrasts with studies in the Kuroshio Extension and the South China Sea,where cyclonic eddies have a more significant forcing effect.This research elucidated the forcing characteristics of mesoscale eddies on air-sea heat flux in the tropical northwest Pacific,identified the critical factors influencing air-sea heat flux,and underscores the regional differences in these processes,and provided an important foundation for further investigation into mesoscale eddy-air-sea coupling mechanisms.
Neo-male fish are induced from genetic females and are indispensable in the large-scale cultivation of all-female seedlings.However,studies on their sperm vitality are scarce in China and the world.To investigate the changes in sperm motility of neo-male yellow drum(Nibea albiflora)during the breeding season and the effects of environmental factors on its motility,we utilized a computer-assisted sperm analysis(CASA)system to assess the sperm concentration,motility,life span,and velocity.Additionally,various temperature and pH gradients were set to determine their effects on sperm motility in the neo-males.Results indicate that the sperm concentration of neo-males ranged(2.24～2.60)× 1010 cells/mL.Throughout the breeding season,the sperm concentration of neo-males exhibited a gradual decline,and during the middle and late stages of breeding,the sperm concentration was significantly higher than that of males.The CASA analysis revealed that sperm motility in neo-males increased at first and then decreased in the breeding season,and the motility rates in neo-males surpassed those of males,although their life span and velocity were lower than those of males.Furthermore,the effects of water temperature and pH on sperm motility during the mid-breeding season were analyzed,using seawater to activate the sperm of neo-males.It was observed that when seawater temperatures ranged from 16 to 24 ℃,the sperm motility rates and life span increased at beginning,and then declined.At 22 ℃,neo-males exhibited the highest motility and life span,recorded at 83.58％and 270.67 s,respectively;however,there were no significant variations in sperm velocity in different activation temperatures.When seawater pH ranged from 6.9 to 8.9,sperm motility of neo-males also displayed an initial increase followed by a decrease.At pH 7.9,neo-males had highest motility and life span,measured at 83.62％and 263.64 s,and exhibited peak speed at this pH level.We demonstrated that the neo-males had higher sperm concentration and motility but a shorter life span compared to the males.Furthermore,both neo-male and male fish sperms exhibited similar trends in motility in response to varying temperature and pH conditions.The present study provides valuable insights for the large-scale production of all-female N.albiflora.
Hyriopsis cumingii and Cristaria plicata are the primary freshwater pearl mussels in China accounting for over 90％of the global pearl production.Developing sperm cryopreservation techniques for these is essential for germplasm conservation and genetic breeding.This study optimized cryopreservation techniques for both species by comparing key parameters such as cryoprotectants,equilibration times,packaging,extenders,and cooling procedures,using sperm motility and survival rates as evaluation indicators.Optimal conditions included 5％and 8％DMSO for H.cumingii and C.plicata sperm,respectively,supplemented with 0.05 mol/L trehalose.The 0.5 mL straw was identified as the optimal container for both species,outperforming 0.25 mL straws and 0.5 mL cryovials.For H.cumingii,the ideal equilibration time was 50 minutes with 5％DMSO,whereas C.plicata showed the best performance with 8％DMSO and an equilibration time of 10 to 30 minutes.Solution D(10-fold dilution of HBSS)outperformed physiological saline and Ringer's solution as a sperm extender,with filtered pond water showing comparable results for C.plicata.Comparison of six cooling protocols identified the optimal cryopreservation procedure for H.cumingii sperm as follows:equilibration at 4 ℃ for 30 minutes,cooling at-7 ℃/min to-30 ℃,holding for 2 minutes,followed by cooling at-12 ℃/min to-80 ℃,holding for another 2 minutes,and finally plunging into liquid nitrogen.For C.plicata sperm,the best protocol involved equilibration at 4 ℃ for 30 minutes,cooling at-7 ℃/min to-80 ℃,holding for 2 minutes,and plunging into liquid nitrogen.Both species achieved the highest motility and survival rates when thawed in a 40 ℃ water bath for 8 seconds.Post-thaw motility and survival rates were 28.57％±2.02％and 71.64％±3.04％for H.cumingii,and 33.38％±3.80％and 64.04％±2.40％for C.plicata,respectively.Artificial fertilization experiments using cryopreserved H.cumingii sperm resulted in a fertilization rate of 43.93％±3.40％.These findings represent a significant advancement in sperm cryopreservation techniques,supporting hybrid breeding efforts and promoting the application of modern biotechnologies.
The distribution and seasonal variation of dissolved organic matter(DOM)can reflect the mechanisms of carbon cycling and sequestration in coastal seas.To investigate the distribution characteristics and seasonal variation of DOM in the Bohai Sea and Yellow Sea(BS and YS),dissolved organic carbon(DOC),chromophoric and fluorescent DOM(CDOM and FDOM)in both the surface and bottom seawater in spring and summer of 2018 were determined.Results show that the average abundance of DOM,as well as its aromaticity,molecular weight,and the relative content of humic-like FDOM were higher in the BS than those in the YS,demonstrating that the composition of DOM in each sub-region was different.There was no significant vertical difference in DOM in the BS and YS in spring due to the well-mixed water column,while in summer,the vertical difference of DOM existed to some extent under the stratified condition.DOC in each region was higher in summer than that in spring,while the seasonal variations of CDOM and FDOM held distinct patterns:CDOM and humic-like FDOM was higher in summer in the BS,south YS(sYS)and bottom water of north YS(nYS),but lower in the surface water of nYS in summer.Protein-like FDOM slightly increased from spring to summer in the BS and sYS,but was relatively constant in the nYS.The overall enhanced DOM in the bottom water was mainly attributed to the microbial transformation of particulate organic matter produced in and settled from the upper layer.According to the correlation analysis,CDOM occupied approximately 50％of the newly produced bulk DOM in the bottom water in the BS,but transparent DOC was the major component in the YS.The newly produced DOM should be microbial labile or semi-labile,and can be further transferred to refractory CDOM and humic-like FDOM,or remineralized to CO2.
To further explore the response relationship between the water and sediment process of the Huanghe(Yellow)River and the changes in scouring and silting in the estuary and its driving forces,remote sensing images,water depth data and related water and sediment data of the study area were analyzed,and the changes in the erosion/deposition center of the Huanghe River estuary since 1976 were studied.Results reveal that from 1977 to 2020,the erosion and deposition dynamics in the Huanghe River estuary and its adjacent sea areas exhibited distinct phased variations.The period from 1977 to 1991 marked a phase of rapid deposition,with an annual net deposition volume exceeding 500 million m3.Between 1997 and 2004,the estuary experienced net erosion.Although deposition volumes increased slightly from 2004 to 2020,the net annual deposition remained below 50 million m3.The shifting of deposition centers was influenced by various factors,including upstream water and sediment supply,river channel morphology,and marine forces such as wind and tides.Changes in channel morphology and flow direction directly influenced the development of sand spits and the location of deposition centers.After the stabilization of the river channel in 1980,sediment deposition tended to converge,and sand spit advanced approximately 16 km southeastward between 1985 and 1997.The artificial diversion in the Qing 8 Branch in 1996 gradually changed the deposition direction from the east to the northeast,and the Qingshuigou Channel changed from deposition to erosion.The swings of the river channel in 2004,2007,and 2013 exacerbated the uneven distribution of sediment and complicated the changes in the erosion/deposition centers.The construction of Xiaolangdi Dam and soil conservation projects have significantly reduced the amount of water and sediment entering the estuary,and slowed down the estuary development.This study provided important scientific basis for the ecological protection and management of the Huanghe River estuary,contributing to the long-term stability and sustainability of its ecosystem.
Spinibarbus hollandi is a commercially important aquaculture species distributed in the southeastern China.To understand its genomic features and mitochondrial genome structure,for the first time,we sequenced the whole genomes of S.hollandi from Zhujiang(Pearl)River(SHZ)and Ganjiang River(SHG)based on Illumina short-read method and subsequently extracted their mitochondrial genomes.Results indicate that the S.hollandi genome is of a simple heterozygous type,with genome sizes of 1 769.91 Mb for SHZ and 1 846.46 Mb for SHG.The mitochondrial genome lengths are 16 543 bp for SHZ and 16 546 bp for SHG.Most genes of the two S.hollandi are in the same length except for 16S rRNA,tRNA-Leu(UUA),and D-loop region.Incomplete codons T/TA were observed in the protein-coding genes.With the exception of tRNA-Ser(GCT),all other tRNAs are able to adopt their expected secondary structures.Utilizing mitochondrial genome sequences,genetic distances among various populations were calculated,and the phylogenetic tree was constructed employing both the Neighbor-Joining method and Bayesian method.Results indicate that the genetic relationship is the closest between the S.hollandi from the Tongjiang River and Ganjiang River,while the relationship between the Taiwan population and the mainland populations is the most distant.The Taiwan population of S.hollandi should be considered a distinct species.This study provided key information for understanding the population genetics and molecular systematics of S.hollandi,and a scientific basis for future germplasm identification,conservation,and utilization.
Air-sea turbulent kinetic energy flux characterizes the exchange of turbulent kinetic energy between the ocean and the atmosphere and it contains important information about the coherent structure of atmospheric turbulence.Based on the observed turbulence data and simultaneous wave data from a fixed offshore platform near Maoming City,Guangdong Province from February 15 to May 8,2012,we investigated and compared the impact of different wave conditions and the atmospheric stability on turbulent kinetic energy flux during low wind-speed period.Spectrum analysis and probability statistical method were employed to quantify the significance and magnitude of the impact.Results show that in the case of swell,there are corresponding areas that obviously affected by swell in the co-spectra and Ogive curves,which indicates that the presence of swell can lead to the reduction of turbulent kinetic energy flux.By normalizing turbulent kinetic energy flux and extracting the positive and negative contribution of turbulent kinetic energy flux,we found that at the same wind speed,the absolute value of the ratio of the negative contribution to the positive contribution of turbulent kinetic energy flux increases with wave age while the normalized turbulent kinetic energy flux value decreases with wave age,which indicate that the reducing effect by swell on turbulent kinetic energy flux tends to increase as wave age increases.In addition,turbulent kinetic energy flux has a higher probability of being negative under swell conditions,with an average probability of about 29％,compared to about 12％in the wind-sea cases.The results also show that atmospheric stability has a significant effect on turbulent kinetic energy flux.At the same wind speed,the turbulent kinetic energy flux in the unstable cases is greater than those in the neutral and stable cases in order.It is turned out that the variation under different atmospheric stabilities results from mainly the positive contribution,while the difference in negative contribution is much smaller.This study confirmed that the effects of swell and atmospheric stability on air-sea turbulent kinetic energy flux is non-negligible under low wind conditions,which offers a scientific reference for a deeper understanding of the atmospheric boundary layer structure.
The addition of fish feed and nutrients in aquaculture water bodies,such as lakes and reservoirs,can lead to excessive algal growth,disrupting ecological balance.Understanding the competitive dynamics of algae in these environments is crucial for elucidating algal blooming mechanism.In this study,we modified nitrogen-free and phosphorus-free M-11 medium by adding fish feed and utilized Microcystis aeruginosa and Scenedesmus obliquus as experimental subjects.Culture conditions were set as follows:daytime 3 000 lx,28 ℃ for 12 hours,and 0 lx,and nighttime 20 ℃ for 12 hours.Algal cell density and nutrient(nitrogen and phosphorus)concentrations were measured,and improved algal growth kinetic and competition models were applied to assess growth and competitive behavior under both monoculture and co-culture conditions.Results show that(1)the maximum algal density of M.aeruginosa was 1 411×104 cells/mL,which was 2.6 times higher than that of S.obliquus.Furthermore,the average specific growth rate of S.obliquus at the beginning of the experimental period(0～4 d)was 0.405 d-1,which was significantly higher than that of M.aeruginosa(0.124 d-1);(2)The average inhibition rate of M.aeruginosa was 22.6％higher than that of S.obliquus under co-culture,while the average competitive inhibition parameter for M.aeruginosa was 2.009 lower than that of S.obliquus,indicating that S.obliquus was dominant in competition.(3)The Lotka-Volterra equation,the improved Monod equation,the improved Logistic equation,and the derived relationship equations based on the improved Logistic equations can effectively describe the growth,competition,and nutrient utilization behaviors of M.aeruginosa and S.obliquus(R2=0.451～0.998).(4)In comparisons between the modified M-11 medium and conventional inorganic media with similar trophic state indices,both algae species achieved higher maximum cell densities in the modified M-11 medium under both monoculture and co-culture conditions.(5)The nutrient release characteristics of fish feed in water facilitated S.obliquus in maintaining a higher specific growth rate during the initial stages of the experiment and enabled rapid nutrient utilization,thus providing it with a competitive advantage in co-culture.This study provided a theoretical guidance and a data support for the prevention and control of algal blooms in aquaculture waters.
Inversion of lake environmental evolution based on lake debris accumulation is one of the main contents of global change research in arid and semi-arid regions.However,most indicator methods are only qualitative and their sensitivity is limited by factors such as the background environment,which affects the in-depth understanding of environmental change and hydroclimatic evolution in inland lakes.Therefore,based on the concept of the order emergence from structure,we developed a quantitative index of system structure also called abnormal index Ai(G)that can be used to describe the evolution of the system structure with the grain size indices,with which we reconstructed the lake level fluctuations of Huangqi Lake(Huangqihai in Chinese)in Nei Mongol(Inner Mongolia),NE China,a terminal lake in the agro-pastoral ecotone of the East Asian monsoon marginal region during 3 600～1 500 cal a BP Results show that under the background of orbit-driven reduction of summer solar radiation,the lake level gradually decreased,showing drastic centennial fluctuation during this period.Comparative analyses on the precipitation and palynolocical data of Gonghai Lake in Shanxi,oxygen isotopic data from stalagmites in Dongge Cave,Guizhou,and Heshang Cave,Hubei,and the intensity of the ENSO activity revealed that such a centennial fluctuation is closely related to the summer monsoon precipitation in the Asian monsoon region driven by solar activity and ENSO activity.When solar radiation weakens,summer monsoon precipitation would decrease while ENSO activity would strengthen,and vice versa.This study revealed the relationship among solar activity,ENSO activity,and summer monsoon intensity,and verified that the quantitative index of system structure with the grain size index system from clastic deposits in terminal lakes of arid and semi-arid regions can be used to better reconstruct the water level change history of the terminal lakes on a centennial-millennial scale.Available studies show that such a reconstruction has quantitative properties,which is of important for the study of global changes in inland lakes.
In order to protect and develop the resources of Acrossocheilus fasciatus,we investigated the extraction,cryopreservation,and transplantation of A.fasciatus oogenous stem cells(AfOSCs).Results showed that AfOSCs were oval,the major and minor axis were(16.52±0.87)μm and(10.66±0.87)μm,respectively.For cryopreservation of A.fasciatus ovary,the 10％dimethyl sulfoxide(DMSO!was the best cryoprotectant,and the AfOSCs extraction efficiency from cryopreserved oval was 42.22％±1.02％compared with the fresh ovarian.The AfOSCs was labeled with PKH26 fluorescent dye and transplanted into the abdominal cavity of 3 days after Danio rerio larvae hatching.At 1～5 day post transplantation(dpt),the PKH26-labeled cells in the recipient larvae were observed in fluorescent microscopy,and the surviving cells migrated toward the posterior dorsal region of abdominal cavity.To detect the quantity changes of transplanted AfOSCs,we developed an absolute quantitative real-time PCR method based on the differences of mitochondrial ND5 sequence between A.fasciatus and D.rerio.At 1 dpt,the A.fasciatus ND5 sequence was(2.51±1.02)×105 copies/100 ng DNA in recipient D.rerio larvaes.The A.fasciatus ND5 copies significantly decreased to(0.78±0.06)×105 copies/100 ng DNA at 3 dpt,and there were no significant difference from 3 dpt to 7 dpt.The results of fluorescent microscopy observation and qRT-PCR detection showed that the transplanted AfOSCs were viable in the recipient D.rerio.Thus,we established oogenous cells extraction,cryopreservation,and transplantation technique for A.fasciatus,which could provide foundation for further studies on genetic resource conservation and germ cell development of A.fasciatus.
Recognizing the patterns of sea ice variation is crucial for studying ecological changes in the polar marginal seas and for planning economic activities.Based on satellite remote sensing data of sea ice concentration from 1979 to 2020,the ERA-5 atmospheric reanalysis data,and retrospective simulation results of the NAPA 1/4 ocean-sea ice coupled model from 1994 to 2019,the regime shift in sea ice area in the Kara Sea and the causes was analyzed.Results show that the Kara Sea experienced a decreasing regime in ice extent in 2005,and the most significant changes occurred in the preceding autumn-winter,and summer,during which thermal effects played the major role,contributing 89％and 91％in the two seasons,respectively.Estimates of heat content in the water column indicate that anomalies in heat content appeared in the summer before those in the preceding autumn-winter.The increase in lateral heat flux was observed in mainly the preceding autumn-winter,while the increase in net heat flux at the sea surface was seen in summer mostly.The anomalously low sea ice concentration in the eastern Kara Sea in the spring of 2004,which was caused by abnormal dynamic transport,led to an anomalous increase in net heat flux at the sea surface in summer,triggering the abrupt decline in sea ice concentration in the Kara Sea.The sustained increase in lateral heat flux in the preceding autumn-winter and the stable increase in net heat flux at the sea surface in summer were the main factors contributing to the persistence of the low sea ice concentration after the regime shift.
During the culture process of marine shellfish,huge amounts of cage attachments are produced,leading to resource waste and environmental pollution.In this study,marine shellfish cage attachments were dried at high temperature and then pulverized into powders to make shellfish mud.Additionally,environmentally eco enzymes were added to ferment shellfish cage mud in solid.Shellfish cage mud-based new feeds were therefore developed as a replacement of traditional sea sediment-based in A.japonicus culture.Results of culture experiments showed that using shellfish cage mud as a substitute of sea sediment to feed A.japonicus was feasible.At the end of culture experiments,no significant difference was observed in the survival rate and specific growth rate(SGR)of the BD group(fed with shellfish cage mud and Zostera marina powder)as compared with the control group(P＞0.05).Nevertheless,survival rate of the BDJ group(fed with environmentally eco enzymes fermented shellfish cage mud Zostera marina powder)was significantly higher than that of the control group(P＜0.05),whereas there was no significant difference in SGRs of these two groups(P＞0.05).The physical and chemical properties of the culture water bodies in the five experimental groups were comparable to each other.The two experimental groups fed with environmental eco enzymes fermented feeds had less culturable Vibrio-bacteria in comparing with the control group(P＜0.05).The bacterial community structures of sediment from different experimental groups were similar.Bacteroidetes,Proteobacteria and Verrucomicrobia were the dominant phyla,while Lutibacter and Haloferula were the dominant genera.Our results showed that it was plausible to use shellfish cage mud as the substitute of marine sediment in feeding A.japonicus,thereby solving the environmental problems caused by the huge accumulation of cage attachments as well as the large-scale mining of sea sediment.
Myxocyprinus asiaticus is a rare freshwater fish species endemic to Asia.However,due to the changes of human activities and ecological environment,the number of the fish has decreased sharply,for which the study of its sperm freezing is important to effectively prevent the germplasm resources from declining.Therefore,healthy males were selected to obtain mature sperm after artificial oxytocin.Four sperm extenders(D-17,D-15,D-20,and artificial seminal plasma A),four cryoprotectants(DMSO,GLY,MeOH,PG),and four concentrations of DMSO(6％,8％,10％,12％)were screened,and their effects on the sperm motility were analyzed.Fresh sperm and frozen semen were used to conduct fertilization experiments.The ultrastructure of spermatozoa from fresh sperm and frozen semen were observed under scanning electron microscope and transmission electron microscope.Result show that using the D-17+8％DMSO to cryopreserve sperm was the best,and the sperm motility was 82.37％±1.65％,of which the fertilization rate and incubation rate showed no significant different from those of fresh sperm's(P＞0.05),and the ultrastructure remained largely normal.However,after cryopreservation,damage to the sperm morphology and structure was obvious,such as sperm head plasma membrane damage,cytoplasmic leakage,cell nuclear membrane damage,and flagella fracture or shedding of the tail.Therefore,cryopreservation using D-17+8％DMSO is recommended for artificial breeding and the establishment of germplasm bank.
The Neosalanx anderssoni is a small-sized economically valuable fish species in China.However,the lack of a rapid and cost-effective sex identification method has hindered research on the molecular mechanisms of sex determination,evolutionary history of sex chromosomes,and aquaculture breeding practices.Through comparison of whole-genome resequencing data between females and males,we identified a genome region with significant differences(chr02:2 798 574～5 434 239 bp).Three female-specific loci of lengths 10 bp,167 bp,and 53 bp were identified based on the analysis of sequencing depth differences.The female-specific 167 bp genomic region was chosen for design of sex specific primers.The results of traditional PCR amplification followed by gel electrophoresis revealed that females exhibited two distinct bands,whereas males displayed a single band with higher intensity than the two female bands.This method was further validated using 22 females and 22 males of known sex from Shuangyanggang and Qinhuangdao populations.To further validate the reliability of our research findings,we randomly selected PCR products of male and female individuals from two populations for sanger sequencing.The sequencing results were consistent with expectations,thereby strongly supporting our research conclusions.Our findings further demonstrated that the sex determination system of N.anderssoni was ZZ/ZW.These results not only enable accurate identification of the sex in N.anderssoni,but also provide valuable theoretical insights into the genetic mechanisms underlying sex determination and the evolutionary dynamics of sex chromosomes.
Under the background of climate change,the uncertainty and complexity of disaster risks have increased.Qingdao is a typical coastal hilly city in the northern China,with relatively lower frequency and intensity of storm surges compared to the southern coastal cities of China.However,in the context of future climate change,the frequency and degree of damage caused by storm surges may increase,and the resulting losses would also increase.This study takes the spatial impact of storm surge inundation risk as the basic starting point,and refines the spatial impact range of storm surge inundation into four categories:storm surge direct inundation zone,wave over dam inundation zone,water accumulation zone that directly affected by tidal top support,and water accumulation zone that indirectly affected by tidal top support.On this basis,relying on the ArcGIS platform,the spatial impact range and changes of storm surge were quantified effectively,and key prevention and control sections and periods were proposed.Results show that compared to the current situation in 2025,under the background of future climate change,as the time scale increases,the scope of the impact of storm surges on the four types of inundation risks in Qingdao and the key prevention and control sections will continue to expand.The impact scope and distribution of some key industrial areas have a clear overlap trend,and the impact scope,key prevention,control sections,and periods will also vary with different types of typhoons.Therefore,clarifying the potential inundation range and period affected by future storm surges can not only help Qingdao avoid the inundation risk caused by storm surges in the short term,but also provide a theoretical basis for disaster prevention management and regional planning and development in the medium to long term.Meanwhile,it can provide a theoretical support to the resilience development of China's northern coastal cities against climate change.
Recirculating aquaculture represents a critical direction in the development of aquaculture,and studying the effects of light on the growth and development of aquatic species in recirculating aquaculture systems is of significant importance for promoting healthy and efficient aquaculture practices.This study focused on the Penaeus japonicus,establishing five photoperiod groups:0L∶24D,6L∶18D,12L∶12D,18L∶6D,and 24L∶0D(L:light,D:dark),to evaluate their effects on growth performance and serum biochemical parameters.Results showed that the 24L∶0D group achieved the highest survival rate(SR),with final body weight,weight gain rate(WGR),and specific growth rate(SGR)also being optimal in this group(P＜0.05),followed by the 12L∶12D group.Serum biochemical analysis revealed that aspartate aminotransferase(AST)activity peaked in the 6L∶18D group,showing no significant difference compared to the 12L∶12D group(P＞0.05),while alanine aminotransferase(ALT)activity was significantly elevated in the 18L∶6D group(P＜0.05).The superoxide dismutase(SOD)in the 0L∶24D group,catalase(CAT)in the 24L∶0D group,and malondialdehyde(MDA)content in the 18L∶6D group were significantly higher than in other groups(P＜0.05).Hormonal analysis revealed that the concentrations of estradiol(E2),gonadotropin-releasing hormone(GnRH),and melatonin(MT)were highest in the 0L:24D group,while cortisol(COR)and glucose(GLU)levels were lowest in the 12L∶12D group.Additionally,serum creatinine(SCR)was significantly elevated in the 12L∶12D group,whereas urea nitrogen(BUN)levels showed no significant differences among groups(P＞0.05).Total protein(TP)and globulin(GLB)concentrations were highest in the 24L∶0D group,followed by the 12L∶12D group.Lipid metabolism analysis revealed significant intergroup variations(P＜0.05),with high-density lipoprotein cholesterol(HDL-C)levels highest in the 6L∶18D group and low-density lipoprotein cholesterol(LDL-C)levels highest in the 18L∶6D group,followed by the 12L∶12D group.Additionally,triglyceride(TG)content was significantly elevated in the 6L∶18D group compared to other groups(P＜0.05).Comprehensive analysis revealed that different photoperiods significantly influenced the growth index and serum biochemical parameters of Penaeus japonicus in the recirculating aquaculture system.Among these,the 12L∶12D photoperiod demonstrated the most favorable conditions for promoting healthy and efficient aquaculture,making it the optimal lighting regime.
The North Pacific Ocean is a sensitive region reflecting global climate change,especially having a significant impact on weather and climate change in East Asia,which is immediately adjacent to the Northwest Pacific Ocean.We selected 28 model results from the Coupled Model Intercomparison Project Phase 6(CMIP6)and computed their multi-model ensemble averaging(MME)model results,and evaluated the seasonal,inter-annual,and inter-decadal variability of the North Pacific sea surface temperature(SST)of 29 models based on a variety of assessment metrics and in comparison with reanalyzed information ERSST v5,using the integrated scoring criteria method.The overall performance of the model results was quantified using a system of comprehensive rating metrics(MR).Results show that the MME is able to accurately simulate year-round and seasonal variations,in which most of the model biases concentrated in January-March and July-September,and the biases of FGOALS-g3 and NorCPM1 are higher than those of other models.The North Pacific SST has a clear upward trend in 1915～2014,with an MME result of 0.055 ℃ per decade,which is similar to the result of the reanalysis data(0.059 ℃ per decade).The correlation coefficient of the two is 0.99,the relative deviation is 0.06,and the relative root-mean-square error is 0.25.Through the comprehensive assessment of the Taylor diagrams,different models perform differently for the same sea area,and the model selection of the region cannot be random.The evaluation results of the MR method show that nine models can be rated as Level A,and the MME rank the third place in Level A,which proved that the model ensemble averaging method could be used to effectively reduce the systematic errors of a single model.
A cyanophage QB2 that infects marine Synechococcus was isolated from an oligotrophic waters of the South China Sea basin.The complete genome of the QB2 was 171 898 bp long,with a G+C content of 41.49％,from which 212 ORFs and 7 tRNAs were identified.The predicted ORFs were categorized into functional modules,including virus particle structural module,DNA and regulatory module,packaging module,and auxiliary metabolic genes.The QB2 carried 20 auxiliary metabolic genes that related to photosynthesis,carbon metabolism,phosphorus metabolism,energy acquisition,and stress regulation,and may play a key role in modulating the energy metabolism of the host during infection.Phylogenetic analysis shows that the QB2 was closely related to the members of the genus Tefnutvirus within the family Kyanoviridae,and had a nucleotide identity of 80.3％with Synechococcus phage S-IOM18,indicating that the QB2 qualified as a novel species in the genus Tefnutvirus.The biogeographic analysis of homologous genes of the cyanophage QB2 shows that it distributes in mainly the epipelagic and mesopelagic zones of temperate and tropical oceans,as well as the Arcticwaters.This study enriched the gene database of cyanophages and provided basic data for further research into the phylogeny of cyanophages and their interactions with the hosts.
