Debate has persisted over whether the metamorphic basement of the Zhoushan Islands,easternmost Cathaysia Block,is Precambrian.Here,representative metamorphic rocks from the Qushan Islands were investigated using petro...Debate has persisted over whether the metamorphic basement of the Zhoushan Islands,easternmost Cathaysia Block,is Precambrian.Here,representative metamorphic rocks from the Qushan Islands were investigated using petrography,mineral chemistry,phase equilibria modeling and SHRIMP zircon U-Pb dating to constrain their metamorphic evolution and tectonic significance.Both the pelitic granulites(garnet-kyanite-perthite-biotite-quartz)and the mafic granulites(garnet-clinopyroxene-amphibole-plagioclase-quartz)reached high-pressure granulite-facies conditions of 1.2-1.4 GPa/820-900℃,and recorded three metamorphic stages along a clockwise P-T path with post-peak isothermal decompression.This trajectory indicated rapid exhumation of thickened continental crust during collisional orogeny.Metamorphic ages of 254±3 Ma,262±4 Ma and 259±3 Ma were obtained for mafic granulite,pelitic granulite and marble,respectively,and were consistent with the emplacement age of 259±4 Ma for a pegmatite vein.Detrital zircons in metasediments spanned 2706-330 Ma,which constrained the latest deposition to~330 Ma;thus represented mid-Paleozoic sediment metamorphosed during the late Paleozoic rather than Precambrian basement.We conclude that the Indosinian tectonothermal event in the Cathaysia Block had originated from late Paleozoic-early Mesozoic collisional orogeny between the South China Plate to the north and the Indochina Block to the south.展开更多
Benthic habitat mapping is an emerging discipline in the international marine field in recent years,providing an effective tool for marine spatial planning,marine ecological management,and decision-making applications...Benthic habitat mapping is an emerging discipline in the international marine field in recent years,providing an effective tool for marine spatial planning,marine ecological management,and decision-making applications.Seabed sediment classification is one of the main contents of seabed habitat mapping.In response to the impact of remote sensing imaging quality and the limitations of acoustic measurement range,where a single data source does not fully reflect the substrate type,we proposed a high-precision seabed habitat sediment classification method that integrates data from multiple sources.Based on WorldView-2 multi-spectral remote sensing image data and multibeam bathymetry data,constructed a random forests(RF)classifier with optimal feature selection.A seabed sediment classification experiment integrating optical remote sensing and acoustic remote sensing data was carried out in the shallow water area of Wuzhizhou Island,Hainan,South China.Different seabed sediment types,such as sand,seagrass,and coral reefs were effectively identified,with an overall classification accuracy of 92%.Experimental results show that RF matrix optimized by fusing multi-source remote sensing data for feature selection were better than the classification results of simple combinations of data sources,which improved the accuracy of seabed sediment classification.Therefore,the method proposed in this paper can be effectively applied to high-precision seabed sediment classification and habitat mapping around islands and reefs.展开更多
By measuring scanning tunneling spectroscopy on some large Bi islands deposited on FeTe_(0.55)Se_(0.45)superconductors,we observe clear in-gap edge states with double peaks at about±1.0 me V on the spectra measur...By measuring scanning tunneling spectroscopy on some large Bi islands deposited on FeTe_(0.55)Se_(0.45)superconductors,we observe clear in-gap edge states with double peaks at about±1.0 me V on the spectra measured near the perimeter of the islands.This feature is very different from the single zero-energy peak observed on some other small Bi islands.The edge states spread towards the inner side of the islands over a width of 2-3 nm.The two edge-state peaks at positive and negative energies move to higher values with the increase of the magnetic field,and they disappear near the transition temperature of FeTe_(0.55)Se_(0.45).Meanwhile,enhanced superconducting gaps are observed in the central regions of these Bi islands,which may be induced by the enhanced pair potential of the topological surface state.Our observations provide a valuable message for the edge state and the proximity-induced superconductivity on specific Bi islands grown on FeTe_(0.55)Se_(0.45)substrate.展开更多
On February 8,2025,a remote area in the Caribbean Sea was rocked by a large M_(W)7.6(USGS,2025) earthquake,centered 209 km SSW of Georgetown,the capital of the Cayman Islands,and the largest city(population~41 000) of...On February 8,2025,a remote area in the Caribbean Sea was rocked by a large M_(W)7.6(USGS,2025) earthquake,centered 209 km SSW of Georgetown,the capital of the Cayman Islands,and the largest city(population~41 000) of the British Overseas Territories(Figure 1).The earthquake was significant due to its large magnitude,potential regional impact,and the possibility of generating a tsunami.展开更多
Tropical coral islands represent one of the extremely stressful ecosystems,characterized by high salinity,seasonal drought,heat,strong ultraviolet radiation,and infertile soil,which constraint species occurrence,limit...Tropical coral islands represent one of the extremely stressful ecosystems,characterized by high salinity,seasonal drought,heat,strong ultraviolet radiation,and infertile soil,which constraint species occurrence,limit plant growth and development,and reduce species richness comparing to tropical continental islands with mesophytic habitats(Li et al.,2024;Ren et al.,2017;Tu et al.,2022,2024).Coupled with global climate changes,these adverse conditions have been being exacerbated,leading to extensive degradation of ecosystems throughout the tropical coral islands(Li et al.,2021).Native insular plant resources provide enormous potentials in island greening and ecological restoration,since they have colonized and become well adapted to the specialized habitat on tropical coral islands,evolving a series of functional traits and molecular strategies to accommodate the abiotic stresses.Thus,understanding the genomic make-up of these plants will help uncover molecular mechanisms underlying adaptation to tropical coral islands.However,contrary to the numerous genomic studies done for other extreme habitats,such as deserts(Hu et al.,2021;Ma et al.,2013),alpine regions(Zhang et al.,2023),intertidal habitats(Feng et al.,2021;Hu et al.,2020;Natarajan et al.,2021),and karst caves(Feng et al.,2020),molecular adaptation of plants on the tropical coral islands remains to be elucidated.展开更多
Analyzing coral reef topography is critical for understanding both the formation mechanisms of coral reefs and coral spatial distribution patterns.However,most topographic studies have focused on small-scale or locali...Analyzing coral reef topography is critical for understanding both the formation mechanisms of coral reefs and coral spatial distribution patterns.However,most topographic studies have focused on small-scale or localized survey sites,and investigations of reef macro-topography patterns and their relationship with coral distribution are scant.To address this gap,we conducted a comprehensive investigation of macro-topographic patterns across 12 coral reefs covering 607 km2 in the Xisha Islands,South China Sea.Using digital elevation models constructed from satellite bathymetric data with 16 m resolution,we analyzed spatial variations of seven topographic indices at the reef,geomorphic zone,and reef slope orientation levels in shallow waters.Field surveys were integrated with topographic indices to interpret and model coral distribution patterns.Our results revealed significant topographic heterogeneity,particularly in reef slopes and lagoon patch reefs.Reef slopes ranged from 0°to 33°,with rugosity values between 1.00 and 1.19.The steepness of reef slopes varied by orientation,being steepest in the west,southwest,and south,while the consistency of slope gradients was highest in the south,east,and northeast.Furthermore,stress-tolerant coral cover on reef slopes was effectively predicted by the factors of topographic indices,water depth,and slope aspect.Additionally,the topographic changes in reef flats and shallow lagoons were minimal.These findings advance our understanding of coral reef formation mechanisms in the Indo-Pacific region and provide a theoretical foundation for the conservation and restoration of coral reef ecosystems.展开更多
The Salmonella pathogenicity islands(SPIs) play crucial roles in the progression of Salmonella infection. In this study, we constructed an improved λ Red homologous recombination system to prepare single and triple d...The Salmonella pathogenicity islands(SPIs) play crucial roles in the progression of Salmonella infection. In this study, we constructed an improved λ Red homologous recombination system to prepare single and triple deletion mutants of 3 prominent SPIs(SPI-1, 2, and 3), aiming at the impact of deletion on morphology, carbon source metabolism, adhesion and invasion capacity, in vivo colonization, and immune efficacy in chicks. Our examination revealed that the surface of the single deletion mutants(SM6ΔSPI1, ΔSPI2, and ΔSPI3) exhibited a more rugged texture and appeared to be enveloped in a layer of transparent colloid, whereas the morphology of the triple deletion mutant(SM6ΔSPI1&2&3) remained unaltered when compared to the parent strain. The carbon metabolic spectrum of the SPI mutants underwent profound alterations, with a notable and statistically significant modification observed in 30 out of 95 carbon sources, primarily carbohydrates(17 out of 30). Furthermore, the adhesion capacity of the 4 mutants to Caco-2 cells was significantly reduced when compared to that of the parent strain. Moreover,the invasion capacity of mutants SM6ΔSPI1 and SM6ΔSPI1&2&3 exhibited a substantial decrease, while it was enhanced to varying degrees for SM6ΔSPI3 and SM6ΔSPI2. Importantly, none of the 4 mutants induced any clinical symptoms in the chicks. However, they did transiently colonize the spleen and liver. Notably, the SM6ΔSPI1&2&3mutant was rapidly cleared from both the spleen and liver within 8 days post-infection and no notable pathological changes were observed in the organs. Additionally, when challenged, the mutants immunized groups displayed a significant increase in antibody levels and alterations in the CD3+CD4+ and CD3+CD8+ subpopulations, and the levels of IL-4 and IFN-γ cytokines in the SM6ΔSPI1&2&3 immunized chicken serum surpassed those of other groups.In summary, the successful construction of the 4 SPI mutants lays the groundwork for further exploration into the pathogenic(including metabolic) mechanisms of SPIs and the development of safe and effective live attenuated Salmonella vaccines or carriers.展开更多
As one of the micro-blocks dispersed in the South China Sea(SCS),the Xisha Islands are covered by thick Cenozoic sedimentary layers,making it challenging to obtain magmatic rocks.Well CK-2 is a kilometer-scale scienti...As one of the micro-blocks dispersed in the South China Sea(SCS),the Xisha Islands are covered by thick Cenozoic sedimentary layers,making it challenging to obtain magmatic rocks.Well CK-2 is a kilometer-scale scientific drilling project on the Xisha Islands in the northwestern SCS.It penetrates the thick reef limestone and reaches basaltic pyroclastic rocks.This study presents the whole-rock and olivine compositions of the basaltic volcaniclastic rocks from Well CK-2.These rocks exhibited ocean island basalt signatures characterized by the enrichment of light rare earth elements and high-field-strength elements.Compared with partial melting products derived from mantle peridotite,whole-rock compositions showed elevated Fe/Mn and Zn/Fe mass ratios.Additionally,olivines were characterized by a lower Ca content,higher Ni content,elevated Fe/Mn mass ratios,and moderate Mn/Zn mass ratios compared to those crystallized from peridotitic melts.The compositions of both the whole-rock and olivine phenocrysts indicate the presence of pyroxenite in the mantle source,which likely formed through the reaction of recycled oceanic crust with the surrounding mantle peridotite.Using the olivine-liquid Mg-Fe exchange thermometer,this study derived mantle potential temperatures(T_(p))ranging from 1502℃to 1756℃,which is consistent with those of plume-related ocean island basalts.Furthermore,the basaltic volcaniclastic rocks exhibit low H_(2)O contents(0.01%–1.47%),which were significantly lower than those found in the primary magmas of Large Igneous Provinces.These results suggest that the basaltic volcaniclastic rocks on the Xisha Islands originated from a volatile-poor mantle plume source.展开更多
Islands are valuable land resources in the ocean,and their detailed subsurface seismic velocity structures are highly important for underground space utilization,engineering construction,and geological disaster preven...Islands are valuable land resources in the ocean,and their detailed subsurface seismic velocity structures are highly important for underground space utilization,engineering construction,and geological disaster prevention.Ambient noise tomography and the horizontal–vertical spectral ratio(HVSR)method use ambient noise recordings instead of earthquake signals to study the underground velocity structure,making them easy to implement on islands and consequently becoming potential optimization schemes for the investigation of detailed island structures.However,the application of these technologies to small granite islands along coasts is relatively insufficient,and the applicability needs to be further verified.This study ambient noise tomography and HVSR analysis were carried out by using a dense array of seismic data on Wuzhizhou Island,Hainan.It was found that natural activities mainly cause the ambient noise below 8 Hz on Wuzhizhou Island.Moreover,high-quality noise cross-correlation functions of 3–8 Hz can be extracted.The results of ambient noise tomography and HVSR analysis show that the underground S-wave velocity structure and sedimentary characteristics of Wuzhizhou Island are coupled with its topography.The high-terrain area of Wuzhizhou Island exhibits low-velocity anomalies,where a sedimentary layer did not develop.On the other hand,the low-terrain area of Wuzhizhou Island exhibits high-velocity anomalies,where a thin Quaternary sedimentary layer developed.These results imply that subsurface magmatic activity controls the island topography and affects the distribution of the island sedimentary layer.This study successfully verifies the feasibility of detection methods based on ambient noise in small granite islands along the coast.It also provides key basic information for studying the geological evolutionary history,island spatial planning,and geological disaster prevention of Wuzhizhou Island.展开更多
The Diaoyu Island(Diaoyu Dao)and its affiliated islands(DAA)have abundant fishery resources,and chlorophyll a(Chl a)concentration is an important marine color element and an important indicator of primary productivity...The Diaoyu Island(Diaoyu Dao)and its affiliated islands(DAA)have abundant fishery resources,and chlorophyll a(Chl a)concentration is an important marine color element and an important indicator of primary productivity in the ocean.Therefore,it is meaningful to understand the distribution and variation characteristics of Chl a concentration in the waters near the DAA.The distribution details of Chl a concentration in the adjacent waters of DAA were revealed by high-resolution satellite GF-1 Wide Field View(WFV)data with 16 m spatial resolution.The results indicate that:(1)The Chl a concentration is between 0.06μg/L and 0.38μg/L throughout the year and the concentration of Chl a in the northeast and east directions of the island(downstream)is significantly higher than that in the west(upstream),and there are observed vortexes with high Chl a concentration in the downstream of DAA.This phenomenon continues to persist in the waters surrounding the DAA all year.(2)The vortex induced by the interaction between the current and island results in the vorticity change of water,inducing the replenishment of a large number of nutrients to the surface,thereby promoting the growth of plankton in the downstream of DAA on the east.In addition,the DAA also plays a significant role in regulating the downstream mix layer depth(MLD).The MLD in the northeast downstream is considerably deeper than the upstream in winter and spring;it is deeper in the east downstream in summer and autumn,and the range of influence for the MLD is greatly larger than the size of the island itself.This shows that the disruption of the DAA on the current is substantial.In addition,the combined effects of SST and wind also play a significant role in modifying Chl a distribution.(3)Based on the analysis above,this study proposes the conception of building fishing pastures downstream of the DAA,and proposes a general migration plan in different seasons to scientifically and rationally utilize and protect the surrounding waters of DAA.展开更多
In the mammalian genome,most CpGs are methylated.However,CpGs within the CpG islands(CGIs)are largely unmethylated,which are important for gene expression regulation.The mechanism underlying the low methylation levels...In the mammalian genome,most CpGs are methylated.However,CpGs within the CpG islands(CGIs)are largely unmethylated,which are important for gene expression regulation.The mechanism underlying the low methylation levels at CGIs remains largely elusive.KDM2 proteins(KDM2A and KDM2B)are H3K36me2 demethylases known to bind specifically at CGIs.Here,we report that depletion of each or both KDM2 proteins,or mutation of all their JmjC domains that harbor the H3K36me2 demethylation activity,leads to an increase in DNA methylation at selective CGIs.The Kdm2a/2b double knockout shows a stronger increase in DNA methylation compared with the single mutant of Kdm2a or Kdm2b,indicating that KDM2A and KDM2B redundantly regulate DNA methylation at CGIs.In addition,the increase of CGI DNA methylation upon mutations of KDM2 proteins is associated with the chromatin environment.Our findings reveal that KDM2A and KDM2B function redundantly in regulating DNA methylation at a subset of CGIs in an H3K36me2 demethylation-dependent manner.展开更多
Coral sand is a unique material developed in the tropical ocean environment, which is mainly composed of coral and other marine organism debris, with the CaCO3 content up to 96 %. It has special physical and mechanica...Coral sand is a unique material developed in the tropical ocean environment, which is mainly composed of coral and other marine organism debris, with the CaCO3 content up to 96 %. It has special physical and mechanical properties due to its composition, structure and sedimentary environment. In this contribution, we discuss its specific gravity, porosity ratio compressibility, crushing, shearing and intensity for coral sand samples from the Nansha islands based on laboratory mechanical tests. Our results show distinct high porosity ratio, high friction angle and low intensity as compared with the quartz sand. We believe that grain crushing is the main factor that influences the deformation and strength of coral sand. Comprehensive study on the physical and mechanical properties of coral sands is significant in providing reliable scientific parameters to construction on coral islet, and thus avoids accidents in construction.展开更多
Symbiotic algae （Symbiodinium sp.） in scleractinian corals are important in understanding how coral reefs will respond to global climate change. The present paper reports on the diversity of Symbiodinium sp. in 48 s...Symbiotic algae （Symbiodinium sp.） in scleractinian corals are important in understanding how coral reefs will respond to global climate change. The present paper reports on the diversity of Symbiodinium sp. in 48 scleractinian coral species from 25 genera and 10 families sampled from the Xisha Islands in the South China Sea, which were identified with the use of restriction fragment length polymorphism （RFLP） of the nuclear ribosomal DNA large subunit gene （rDNA）. The results showed that： （i） Symbiodinium Clade C was the dominant zooxanthellae in scleractinian corals in the Xisha Islands; （ii） Symbiodinium Clade D was found in the corals Montipora aequituberculata, Galaxea fascicularis, and Plerogyra sinuosa; and （iii） both Symbiodinium Clades C and D were found simultaneously in Montipora digitata, Psammocora contigua, and Galaxeafascicularis. A poor capacity for symbiosis polymorphism, as uncovered by RFLP, in the Xisha Islands indicates that the scleractinian corals have low adaptability to environmental changes. Further studies are needed to investigate zooxanthellae diversity using other molecular markers.展开更多
Haihua Islands is a large artificial island in Danzhou, Hainan. The construction of Haihua Islands changes the hYdrodynamic environment of Yangpu waters, and further affects its morphological change. Delft3D is used t...Haihua Islands is a large artificial island in Danzhou, Hainan. The construction of Haihua Islands changes the hYdrodynamic environment of Yangpu waters, and further affects its morphological change. Delft3D is used to set up a two dimensional nested hydrodynamic and sediment model for Yangpu waters in this paper, and this paper focuses on simulating the velocity and morphological change due to the construction of Haihua Islands after the verification of the model. The seabed deposition is small because of low suspended sediment concentration and less sand source near Yangpu waters. The bed level erodes in the south area of Xiaochan Reef and the Yangpu channel due to the velocity increase in the area.展开更多
Seasonal cycles are essential components of weather and climatic systems. This study utilized observational data from a meteorological station on an island in the South China Sea from 1961 to 2020, along with ERA5 rea...Seasonal cycles are essential components of weather and climatic systems. This study utilized observational data from a meteorological station on an island in the South China Sea from 1961 to 2020, along with ERA5 reanalysis data, to explore the variations in seasonal cycles and thermal comfort characteristics on the island. The observational data revealed that the onset of summer on the island occurred earlier each year, whereas the onset of autumn was gradually delayed,leading to an increase in the duration of summer. Urbanization had played an important role in elevating local temperatures and extending the duration of summer. The thermal comfort index exhibited a clear upward trend annually, reflecting a shift towards warmer and less comfortable conditions due to urbanization. From 1961 to 2020, the annual average thermal comfort index indicated that 36 years(60%) were characterized by hot discomfort, and 24 years(40%) were within the comfortable range. The number of comfortable days per year on the island exhibited a declining trend. Urbanization markedly influenced the thermal comfort levels on the island, contributing to an annual increase in the number of hot discomfort days. However, the reanalysis data did not reflect the actual observed changes in the comfort characteristics on the island.展开更多
Siemens and Yangpu Economic Development Zone in Hainan have forged a close partnership in a journey towards green energy transition.SIEMENS Energy,one of the world’s leading energy technology companies,became the fir...Siemens and Yangpu Economic Development Zone in Hainan have forged a close partnership in a journey towards green energy transition.SIEMENS Energy,one of the world’s leading energy technology companies,became the first foreign-funded manufacturer to establish a branch and began construction of a gas turbine assembly base and service center in Hainan on December 18,2025.展开更多
A deep-water harbour in Hainan has emerged as a pivotal gateway to regions around the world Located on the northwest tip of Hainan Island,Yangpu Port is bustling with activity,with towering gantry cranes frantically l...A deep-water harbour in Hainan has emerged as a pivotal gateway to regions around the world Located on the northwest tip of Hainan Island,Yangpu Port is bustling with activity,with towering gantry cranes frantically loading containers on and off large cargo vessels.Cargo volumes here have surged as a result of a slew of special customs policies that went into force in December 2025.展开更多
THE Hainan Free Trade Port(FTP)officially launched island-wide special customs operations on December 18,2025.One month in,a reporting team from China International Communications Group(CICG)conducted an exclusive int...THE Hainan Free Trade Port(FTP)officially launched island-wide special customs operations on December 18,2025.One month in,a reporting team from China International Communications Group(CICG)conducted an exclusive interview with Feng Fei,secretary of the Hainan Provincial Committee of the Communist Party of China(CPC)and chairman of the Standing Committee of the Hainan Provincial People’s Congress.展开更多
The Hainan Free Trade Port(FTP),with the launching of island-wide special customs operations,is allowing greater convenience for overseas goods to enter the island,trying to build it into an efficient hub connecting C...The Hainan Free Trade Port(FTP),with the launching of island-wide special customs operations,is allowing greater convenience for overseas goods to enter the island,trying to build it into an efficient hub connecting China with the rest of the world.Its core appeal no longer relies solely on policy incentives but has shifted toward transparent and predictable institutional guarantees which provide stable expectations for global investors.展开更多
In this study, we simulated typhoon waves in the shallow waters around the Zhoushan Islands using the WaveWatch-Ⅲ(WW3) model version 5.16, the latest version released by the National Oceanic and Atmospheric Administr...In this study, we simulated typhoon waves in the shallow waters around the Zhoushan Islands using the WaveWatch-Ⅲ(WW3) model version 5.16, the latest version released by the National Oceanic and Atmospheric Administration. Specifically, we used in-situ measurements to evaluate the performance of seven packages of input/dissipation source terms in the WW3 model. We forced the WW3 model by wind fields derived from a combination of the parametric Holland model and high-resolution European Center for Medium-Range Weather Forecasts(ECMWF) wind data in a 0.125? grid, herein called H-E winds. We trained the H-E winds by fitting a shape parameter B to buoy-measured observations, which resulted in a smallest root mean square error(RMSE) of 3 m s^(-1) for B, when treated as a constant 0.4. Then, we applied the seven input/dissipation terms of WW3, labelled ST1, ST2, ST2+STAB2, ST3, ST3+STAB3, ST4, and ST6, to simulate the significant wave height(SWH) up to 5 m during typhoons Fungwong and Chan-hom around the Zhoushan Islands. We then compared the SWHs of the simulated waves with those measured by the in-situ buoys. The results indicate that the simulation using ST2 performs best with an RMSE of 0.79 m for typhoon Fung-wong and an RMSE of 1.12 m for typhoon Chan-hom. Interestingly, we found the simulated SWH results to be relatively higher than those of the observations in the area between Hangzhou Bay and the Zhoushan Islands. This behavior is worthy of further investigation in the future.展开更多
基金supported by the National Natural Science Foundation of China(42072223)Geological Survey project(DD20221649,DD20231429).
文摘Debate has persisted over whether the metamorphic basement of the Zhoushan Islands,easternmost Cathaysia Block,is Precambrian.Here,representative metamorphic rocks from the Qushan Islands were investigated using petrography,mineral chemistry,phase equilibria modeling and SHRIMP zircon U-Pb dating to constrain their metamorphic evolution and tectonic significance.Both the pelitic granulites(garnet-kyanite-perthite-biotite-quartz)and the mafic granulites(garnet-clinopyroxene-amphibole-plagioclase-quartz)reached high-pressure granulite-facies conditions of 1.2-1.4 GPa/820-900℃,and recorded three metamorphic stages along a clockwise P-T path with post-peak isothermal decompression.This trajectory indicated rapid exhumation of thickened continental crust during collisional orogeny.Metamorphic ages of 254±3 Ma,262±4 Ma and 259±3 Ma were obtained for mafic granulite,pelitic granulite and marble,respectively,and were consistent with the emplacement age of 259±4 Ma for a pegmatite vein.Detrital zircons in metasediments spanned 2706-330 Ma,which constrained the latest deposition to~330 Ma;thus represented mid-Paleozoic sediment metamorphosed during the late Paleozoic rather than Precambrian basement.We conclude that the Indosinian tectonothermal event in the Cathaysia Block had originated from late Paleozoic-early Mesozoic collisional orogeny between the South China Plate to the north and the Indochina Block to the south.
基金Supported by the National Natural Science Foundation of China(Nos.42376185,41876111)the Shandong Provincial Natural Science Foundation(No.ZR2023MD073)。
文摘Benthic habitat mapping is an emerging discipline in the international marine field in recent years,providing an effective tool for marine spatial planning,marine ecological management,and decision-making applications.Seabed sediment classification is one of the main contents of seabed habitat mapping.In response to the impact of remote sensing imaging quality and the limitations of acoustic measurement range,where a single data source does not fully reflect the substrate type,we proposed a high-precision seabed habitat sediment classification method that integrates data from multiple sources.Based on WorldView-2 multi-spectral remote sensing image data and multibeam bathymetry data,constructed a random forests(RF)classifier with optimal feature selection.A seabed sediment classification experiment integrating optical remote sensing and acoustic remote sensing data was carried out in the shallow water area of Wuzhizhou Island,Hainan,South China.Different seabed sediment types,such as sand,seagrass,and coral reefs were effectively identified,with an overall classification accuracy of 92%.Experimental results show that RF matrix optimized by fusing multi-source remote sensing data for feature selection were better than the classification results of simple combinations of data sources,which improved the accuracy of seabed sediment classification.Therefore,the method proposed in this paper can be effectively applied to high-precision seabed sediment classification and habitat mapping around islands and reefs.
基金supported by the National Key R&D Program of China(Grant Nos.2022YFA1403201 and 2024YFA1408104)the National Natural Science Foundation of China(Grant Nos.11927809 and 12434004)the Natural Science Foundation of Jiangsu Province(Grant No.BK20233001)。
文摘By measuring scanning tunneling spectroscopy on some large Bi islands deposited on FeTe_(0.55)Se_(0.45)superconductors,we observe clear in-gap edge states with double peaks at about±1.0 me V on the spectra measured near the perimeter of the islands.This feature is very different from the single zero-energy peak observed on some other small Bi islands.The edge states spread towards the inner side of the islands over a width of 2-3 nm.The two edge-state peaks at positive and negative energies move to higher values with the increase of the magnetic field,and they disappear near the transition temperature of FeTe_(0.55)Se_(0.45).Meanwhile,enhanced superconducting gaps are observed in the central regions of these Bi islands,which may be induced by the enhanced pair potential of the topological surface state.Our observations provide a valuable message for the edge state and the proximity-induced superconductivity on specific Bi islands grown on FeTe_(0.55)Se_(0.45)substrate.
文摘On February 8,2025,a remote area in the Caribbean Sea was rocked by a large M_(W)7.6(USGS,2025) earthquake,centered 209 km SSW of Georgetown,the capital of the Cayman Islands,and the largest city(population~41 000) of the British Overseas Territories(Figure 1).The earthquake was significant due to its large magnitude,potential regional impact,and the possibility of generating a tsunami.
基金supported by the National Natural Science Foundation of China(32170232,32070222,32271613)the National Key R&D Programof China(Key Special Project for Marine Environmental Security and Sustainable Development of Coral Reefs 2021-400)+1 种基金Guangdong Science and Technology Program(2024B1212050007)the National Key Research and Development Program of China(2021YFC3100405)。
文摘Tropical coral islands represent one of the extremely stressful ecosystems,characterized by high salinity,seasonal drought,heat,strong ultraviolet radiation,and infertile soil,which constraint species occurrence,limit plant growth and development,and reduce species richness comparing to tropical continental islands with mesophytic habitats(Li et al.,2024;Ren et al.,2017;Tu et al.,2022,2024).Coupled with global climate changes,these adverse conditions have been being exacerbated,leading to extensive degradation of ecosystems throughout the tropical coral islands(Li et al.,2021).Native insular plant resources provide enormous potentials in island greening and ecological restoration,since they have colonized and become well adapted to the specialized habitat on tropical coral islands,evolving a series of functional traits and molecular strategies to accommodate the abiotic stresses.Thus,understanding the genomic make-up of these plants will help uncover molecular mechanisms underlying adaptation to tropical coral islands.However,contrary to the numerous genomic studies done for other extreme habitats,such as deserts(Hu et al.,2021;Ma et al.,2013),alpine regions(Zhang et al.,2023),intertidal habitats(Feng et al.,2021;Hu et al.,2020;Natarajan et al.,2021),and karst caves(Feng et al.,2020),molecular adaptation of plants on the tropical coral islands remains to be elucidated.
基金The Guangxi Science and Technology Program under contract No.AD25069075the National Natural Science Foundation of China under contract No.42276182+2 种基金the Major Talent Project of Guangxi Zhuang Autonomous Region under contract No.GXR-2BGQ2525027the Natural Science and Technology Innovation Development Doubling Program of Guangxi University under contract No.2023BZRC019the Guangxi Natural Science Foundation of China under contract No.2022GXNSFAA035548.
文摘Analyzing coral reef topography is critical for understanding both the formation mechanisms of coral reefs and coral spatial distribution patterns.However,most topographic studies have focused on small-scale or localized survey sites,and investigations of reef macro-topography patterns and their relationship with coral distribution are scant.To address this gap,we conducted a comprehensive investigation of macro-topographic patterns across 12 coral reefs covering 607 km2 in the Xisha Islands,South China Sea.Using digital elevation models constructed from satellite bathymetric data with 16 m resolution,we analyzed spatial variations of seven topographic indices at the reef,geomorphic zone,and reef slope orientation levels in shallow waters.Field surveys were integrated with topographic indices to interpret and model coral distribution patterns.Our results revealed significant topographic heterogeneity,particularly in reef slopes and lagoon patch reefs.Reef slopes ranged from 0°to 33°,with rugosity values between 1.00 and 1.19.The steepness of reef slopes varied by orientation,being steepest in the west,southwest,and south,while the consistency of slope gradients was highest in the south,east,and northeast.Furthermore,stress-tolerant coral cover on reef slopes was effectively predicted by the factors of topographic indices,water depth,and slope aspect.Additionally,the topographic changes in reef flats and shallow lagoons were minimal.These findings advance our understanding of coral reef formation mechanisms in the Indo-Pacific region and provide a theoretical foundation for the conservation and restoration of coral reef ecosystems.
基金supported by the National KeyR&DProgramof China(2022YFF0710500)the National Natural Science Foundation of China(32172853 and 32373013)the Central Public-interest Scientific Institution Basal Research Fund,China(1610302022001).
文摘The Salmonella pathogenicity islands(SPIs) play crucial roles in the progression of Salmonella infection. In this study, we constructed an improved λ Red homologous recombination system to prepare single and triple deletion mutants of 3 prominent SPIs(SPI-1, 2, and 3), aiming at the impact of deletion on morphology, carbon source metabolism, adhesion and invasion capacity, in vivo colonization, and immune efficacy in chicks. Our examination revealed that the surface of the single deletion mutants(SM6ΔSPI1, ΔSPI2, and ΔSPI3) exhibited a more rugged texture and appeared to be enveloped in a layer of transparent colloid, whereas the morphology of the triple deletion mutant(SM6ΔSPI1&2&3) remained unaltered when compared to the parent strain. The carbon metabolic spectrum of the SPI mutants underwent profound alterations, with a notable and statistically significant modification observed in 30 out of 95 carbon sources, primarily carbohydrates(17 out of 30). Furthermore, the adhesion capacity of the 4 mutants to Caco-2 cells was significantly reduced when compared to that of the parent strain. Moreover,the invasion capacity of mutants SM6ΔSPI1 and SM6ΔSPI1&2&3 exhibited a substantial decrease, while it was enhanced to varying degrees for SM6ΔSPI3 and SM6ΔSPI2. Importantly, none of the 4 mutants induced any clinical symptoms in the chicks. However, they did transiently colonize the spleen and liver. Notably, the SM6ΔSPI1&2&3mutant was rapidly cleared from both the spleen and liver within 8 days post-infection and no notable pathological changes were observed in the organs. Additionally, when challenged, the mutants immunized groups displayed a significant increase in antibody levels and alterations in the CD3+CD4+ and CD3+CD8+ subpopulations, and the levels of IL-4 and IFN-γ cytokines in the SM6ΔSPI1&2&3 immunized chicken serum surpassed those of other groups.In summary, the successful construction of the 4 SPI mutants lays the groundwork for further exploration into the pathogenic(including metabolic) mechanisms of SPIs and the development of safe and effective live attenuated Salmonella vaccines or carriers.
基金The National Natural Science Foundation of China under contract No.42030502the Guangxi Scientific Projects under contract Nos.AD17129063,AA17204074,and 2025GXNSFAA069324the NSFC project under contract No.42166003。
文摘As one of the micro-blocks dispersed in the South China Sea(SCS),the Xisha Islands are covered by thick Cenozoic sedimentary layers,making it challenging to obtain magmatic rocks.Well CK-2 is a kilometer-scale scientific drilling project on the Xisha Islands in the northwestern SCS.It penetrates the thick reef limestone and reaches basaltic pyroclastic rocks.This study presents the whole-rock and olivine compositions of the basaltic volcaniclastic rocks from Well CK-2.These rocks exhibited ocean island basalt signatures characterized by the enrichment of light rare earth elements and high-field-strength elements.Compared with partial melting products derived from mantle peridotite,whole-rock compositions showed elevated Fe/Mn and Zn/Fe mass ratios.Additionally,olivines were characterized by a lower Ca content,higher Ni content,elevated Fe/Mn mass ratios,and moderate Mn/Zn mass ratios compared to those crystallized from peridotitic melts.The compositions of both the whole-rock and olivine phenocrysts indicate the presence of pyroxenite in the mantle source,which likely formed through the reaction of recycled oceanic crust with the surrounding mantle peridotite.Using the olivine-liquid Mg-Fe exchange thermometer,this study derived mantle potential temperatures(T_(p))ranging from 1502℃to 1756℃,which is consistent with those of plume-related ocean island basalts.Furthermore,the basaltic volcaniclastic rocks exhibit low H_(2)O contents(0.01%–1.47%),which were significantly lower than those found in the primary magmas of Large Igneous Provinces.These results suggest that the basaltic volcaniclastic rocks on the Xisha Islands originated from a volatile-poor mantle plume source.
基金supported by the geological survey project(Grant No.DD20220992,Grant No.DD20242841,Grant No.DD20230592 and Grant No.DD20220993)Innovation Foundation of Science and Technology for“Nanhai New Star”Projects(Grant No.NHXXRCXM202353)of Hainan province。
文摘Islands are valuable land resources in the ocean,and their detailed subsurface seismic velocity structures are highly important for underground space utilization,engineering construction,and geological disaster prevention.Ambient noise tomography and the horizontal–vertical spectral ratio(HVSR)method use ambient noise recordings instead of earthquake signals to study the underground velocity structure,making them easy to implement on islands and consequently becoming potential optimization schemes for the investigation of detailed island structures.However,the application of these technologies to small granite islands along coasts is relatively insufficient,and the applicability needs to be further verified.This study ambient noise tomography and HVSR analysis were carried out by using a dense array of seismic data on Wuzhizhou Island,Hainan.It was found that natural activities mainly cause the ambient noise below 8 Hz on Wuzhizhou Island.Moreover,high-quality noise cross-correlation functions of 3–8 Hz can be extracted.The results of ambient noise tomography and HVSR analysis show that the underground S-wave velocity structure and sedimentary characteristics of Wuzhizhou Island are coupled with its topography.The high-terrain area of Wuzhizhou Island exhibits low-velocity anomalies,where a sedimentary layer did not develop.On the other hand,the low-terrain area of Wuzhizhou Island exhibits high-velocity anomalies,where a thin Quaternary sedimentary layer developed.These results imply that subsurface magmatic activity controls the island topography and affects the distribution of the island sedimentary layer.This study successfully verifies the feasibility of detection methods based on ambient noise in small granite islands along the coast.It also provides key basic information for studying the geological evolutionary history,island spatial planning,and geological disaster prevention of Wuzhizhou Island.
基金The Basic Public Welfare Research Program of Zhejiang Province under contract No.LGF21D010004the Key R&D Projects in Zhejiang Province under contract No.2023C03120.
文摘The Diaoyu Island(Diaoyu Dao)and its affiliated islands(DAA)have abundant fishery resources,and chlorophyll a(Chl a)concentration is an important marine color element and an important indicator of primary productivity in the ocean.Therefore,it is meaningful to understand the distribution and variation characteristics of Chl a concentration in the waters near the DAA.The distribution details of Chl a concentration in the adjacent waters of DAA were revealed by high-resolution satellite GF-1 Wide Field View(WFV)data with 16 m spatial resolution.The results indicate that:(1)The Chl a concentration is between 0.06μg/L and 0.38μg/L throughout the year and the concentration of Chl a in the northeast and east directions of the island(downstream)is significantly higher than that in the west(upstream),and there are observed vortexes with high Chl a concentration in the downstream of DAA.This phenomenon continues to persist in the waters surrounding the DAA all year.(2)The vortex induced by the interaction between the current and island results in the vorticity change of water,inducing the replenishment of a large number of nutrients to the surface,thereby promoting the growth of plankton in the downstream of DAA on the east.In addition,the DAA also plays a significant role in regulating the downstream mix layer depth(MLD).The MLD in the northeast downstream is considerably deeper than the upstream in winter and spring;it is deeper in the east downstream in summer and autumn,and the range of influence for the MLD is greatly larger than the size of the island itself.This shows that the disruption of the DAA on the current is substantial.In addition,the combined effects of SST and wind also play a significant role in modifying Chl a distribution.(3)Based on the analysis above,this study proposes the conception of building fishing pastures downstream of the DAA,and proposes a general migration plan in different seasons to scientifically and rationally utilize and protect the surrounding waters of DAA.
基金supported by the National Natural Science Foundation of China(32070607)the National Key Research and Development Program of China(2020YFA0804000)the CAS Project for Young Scientists in Basic Research(YSBR-012).
文摘In the mammalian genome,most CpGs are methylated.However,CpGs within the CpG islands(CGIs)are largely unmethylated,which are important for gene expression regulation.The mechanism underlying the low methylation levels at CGIs remains largely elusive.KDM2 proteins(KDM2A and KDM2B)are H3K36me2 demethylases known to bind specifically at CGIs.Here,we report that depletion of each or both KDM2 proteins,or mutation of all their JmjC domains that harbor the H3K36me2 demethylation activity,leads to an increase in DNA methylation at selective CGIs.The Kdm2a/2b double knockout shows a stronger increase in DNA methylation compared with the single mutant of Kdm2a or Kdm2b,indicating that KDM2A and KDM2B redundantly regulate DNA methylation at CGIs.In addition,the increase of CGI DNA methylation upon mutations of KDM2 proteins is associated with the chromatin environment.Our findings reveal that KDM2A and KDM2B function redundantly in regulating DNA methylation at a subset of CGIs in an H3K36me2 demethylation-dependent manner.
文摘Coral sand is a unique material developed in the tropical ocean environment, which is mainly composed of coral and other marine organism debris, with the CaCO3 content up to 96 %. It has special physical and mechanical properties due to its composition, structure and sedimentary environment. In this contribution, we discuss its specific gravity, porosity ratio compressibility, crushing, shearing and intensity for coral sand samples from the Nansha islands based on laboratory mechanical tests. Our results show distinct high porosity ratio, high friction angle and low intensity as compared with the quartz sand. We believe that grain crushing is the main factor that influences the deformation and strength of coral sand. Comprehensive study on the physical and mechanical properties of coral sands is significant in providing reliable scientific parameters to construction on coral islet, and thus avoids accidents in construction.
基金supported by grantsfrom the National Natural Science Fundation of China(40776085 and 40576052)State Oceanic Administration of China(908-ST-01-08-Coral Reefs Survey)Bureau of Science and Technology for Resources and Environment(YTZJJ0502)
文摘Symbiotic algae （Symbiodinium sp.） in scleractinian corals are important in understanding how coral reefs will respond to global climate change. The present paper reports on the diversity of Symbiodinium sp. in 48 scleractinian coral species from 25 genera and 10 families sampled from the Xisha Islands in the South China Sea, which were identified with the use of restriction fragment length polymorphism （RFLP） of the nuclear ribosomal DNA large subunit gene （rDNA）. The results showed that： （i） Symbiodinium Clade C was the dominant zooxanthellae in scleractinian corals in the Xisha Islands; （ii） Symbiodinium Clade D was found in the corals Montipora aequituberculata, Galaxea fascicularis, and Plerogyra sinuosa; and （iii） both Symbiodinium Clades C and D were found simultaneously in Montipora digitata, Psammocora contigua, and Galaxeafascicularis. A poor capacity for symbiosis polymorphism, as uncovered by RFLP, in the Xisha Islands indicates that the scleractinian corals have low adaptability to environmental changes. Further studies are needed to investigate zooxanthellae diversity using other molecular markers.
文摘Haihua Islands is a large artificial island in Danzhou, Hainan. The construction of Haihua Islands changes the hYdrodynamic environment of Yangpu waters, and further affects its morphological change. Delft3D is used to set up a two dimensional nested hydrodynamic and sediment model for Yangpu waters in this paper, and this paper focuses on simulating the velocity and morphological change due to the construction of Haihua Islands after the verification of the model. The seabed deposition is small because of low suspended sediment concentration and less sand source near Yangpu waters. The bed level erodes in the south area of Xiaochan Reef and the Yangpu channel due to the velocity increase in the area.
基金National Natural Science Foundation of China(U21A6001,42475077)Innovation Platform for Academicians of Hainan Province。
文摘Seasonal cycles are essential components of weather and climatic systems. This study utilized observational data from a meteorological station on an island in the South China Sea from 1961 to 2020, along with ERA5 reanalysis data, to explore the variations in seasonal cycles and thermal comfort characteristics on the island. The observational data revealed that the onset of summer on the island occurred earlier each year, whereas the onset of autumn was gradually delayed,leading to an increase in the duration of summer. Urbanization had played an important role in elevating local temperatures and extending the duration of summer. The thermal comfort index exhibited a clear upward trend annually, reflecting a shift towards warmer and less comfortable conditions due to urbanization. From 1961 to 2020, the annual average thermal comfort index indicated that 36 years(60%) were characterized by hot discomfort, and 24 years(40%) were within the comfortable range. The number of comfortable days per year on the island exhibited a declining trend. Urbanization markedly influenced the thermal comfort levels on the island, contributing to an annual increase in the number of hot discomfort days. However, the reanalysis data did not reflect the actual observed changes in the comfort characteristics on the island.
文摘Siemens and Yangpu Economic Development Zone in Hainan have forged a close partnership in a journey towards green energy transition.SIEMENS Energy,one of the world’s leading energy technology companies,became the first foreign-funded manufacturer to establish a branch and began construction of a gas turbine assembly base and service center in Hainan on December 18,2025.
文摘A deep-water harbour in Hainan has emerged as a pivotal gateway to regions around the world Located on the northwest tip of Hainan Island,Yangpu Port is bustling with activity,with towering gantry cranes frantically loading containers on and off large cargo vessels.Cargo volumes here have surged as a result of a slew of special customs policies that went into force in December 2025.
文摘THE Hainan Free Trade Port(FTP)officially launched island-wide special customs operations on December 18,2025.One month in,a reporting team from China International Communications Group(CICG)conducted an exclusive interview with Feng Fei,secretary of the Hainan Provincial Committee of the Communist Party of China(CPC)and chairman of the Standing Committee of the Hainan Provincial People’s Congress.
文摘The Hainan Free Trade Port(FTP),with the launching of island-wide special customs operations,is allowing greater convenience for overseas goods to enter the island,trying to build it into an efficient hub connecting China with the rest of the world.Its core appeal no longer relies solely on policy incentives but has shifted toward transparent and predictable institutional guarantees which provide stable expectations for global investors.
基金partly supported by the National Key Research and Development Program of China under contract (Nos. 2017YFA0604901, 2016YFC 1401002 and 2016YFC1402000)the National Natural Science Foundation of China under contract (Nos. 41776 183, 41606024 and 41506033)
文摘In this study, we simulated typhoon waves in the shallow waters around the Zhoushan Islands using the WaveWatch-Ⅲ(WW3) model version 5.16, the latest version released by the National Oceanic and Atmospheric Administration. Specifically, we used in-situ measurements to evaluate the performance of seven packages of input/dissipation source terms in the WW3 model. We forced the WW3 model by wind fields derived from a combination of the parametric Holland model and high-resolution European Center for Medium-Range Weather Forecasts(ECMWF) wind data in a 0.125? grid, herein called H-E winds. We trained the H-E winds by fitting a shape parameter B to buoy-measured observations, which resulted in a smallest root mean square error(RMSE) of 3 m s^(-1) for B, when treated as a constant 0.4. Then, we applied the seven input/dissipation terms of WW3, labelled ST1, ST2, ST2+STAB2, ST3, ST3+STAB3, ST4, and ST6, to simulate the significant wave height(SWH) up to 5 m during typhoons Fungwong and Chan-hom around the Zhoushan Islands. We then compared the SWHs of the simulated waves with those measured by the in-situ buoys. The results indicate that the simulation using ST2 performs best with an RMSE of 0.79 m for typhoon Fung-wong and an RMSE of 1.12 m for typhoon Chan-hom. Interestingly, we found the simulated SWH results to be relatively higher than those of the observations in the area between Hangzhou Bay and the Zhoushan Islands. This behavior is worthy of further investigation in the future.
