Changes in vegetation status generally also represents changes in the ecological health of islands and reefs(IRs).However,studies are limited of drivers and trends of vegetation change of Nansha Islands,China and how ...Changes in vegetation status generally also represents changes in the ecological health of islands and reefs(IRs).However,studies are limited of drivers and trends of vegetation change of Nansha Islands,China and how they relate to climate change and human activities.To resolve this limitation,we studied changes to the Normalized Difference Vegetation Index(NDVI)vegetation-greenness index for 22 IRs of Nansha Islands during normal and extreme conditions.Trends of vegetation greenness were analyzed using Sen's slope and Mann-Kendall test at two spatial scales(pixel and island),and driving factor analyses were performed by time-lagged partial correlation analyses.These were related to impacts from human activities and climatic factors under normal(temperature,precipitation,radiation,and Normalized Difference Built-up Index(NDBI))and extreme conditions(wind speed and latitude of IRs)from 2016 to 2022.Results showed:1)among the 22 IRs,NDVI increased/decreased significantly in 15/4 IRs,respectively.Huayang Reef had the highest NDVI change-rate(0.48%/mon),and Zhongye Island had the lowest(–0.29%/mon).Local spatial patterns were in one of two forms:dotted-form,and degradation in banded-form.2)Under normal conditions,human activities(characterized by NDBI)had higher impacts on vegetation-greenness than other factors.3)Under extreme conditions,wind speed(R^(2)=0.2337,P<0.05)and latitude(R^(2)=0.2769,P<0.05)provided limited explanation for changes from typhoon events.Our results provide scientific support for the sustainable development of Nansha Islands and the United Nations‘Ocean Decade’initiative.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
Dynamics of major picoplankton groups, Synechococcus (Syn), Prochlorococcus (Pro), picoeukaryotes (Euk) and heterotrophic bacteria (Bact) was investigated by flow cytometry for the first time in the Nansha Islands are...Dynamics of major picoplankton groups, Synechococcus (Syn), Prochlorococcus (Pro), picoeukaryotes (Euk) and heterotrophic bacteria (Bact) was investigated by flow cytometry for the first time in the Nansha Islands area in the South China Sea. Averaged over the whole investigation area, depth-weighted integrated cell abundance (DWA) of Syn, Pro, Euk and Bact was 1.6 (0.4-5.7)×103, 5.4 (0.1-7.3)×104, 0.7 (0.2-2.2)×103, and 2.3 (1.4-3.2)×105 cells/mL respectively. Picoautotrophic cell abundance was low in the northwest part of the Nansha Islands where surface water temperature was low and the upper mixed layer was shallow. Concurrently, a surface maximum vertical distribution pattern was observed in this area. While in the southeast and east zones where temperatures were relatively higher and nitraclines were deeper, picoplankton is abundant and a subsurface maximum around 50-75 m is observed. Coupling of horizontal and vertical distribution patterns of picoplankton abundance and hydrological status was found, suggesting a strong influence of currents and water column structure on picoplankton distribution in the investigation area. Contrary to that in the shelf water in the East China Sea, the relationship between Pro and Bact in the Nansha Islands area in the South China Sea was not significantly negative but weakly positive. Moreover, a similar distribution pattern of Syn and Pro was observed. Possible reasons for these differences in the two marine regimes were discussed.展开更多
A detailed survey of the reefs in the Nansha Islands' sea that are of strategic importance is conducive to their future development. In this study, a total of 50 Landsat 8 operational land imager(OLI) images were u...A detailed survey of the reefs in the Nansha Islands' sea that are of strategic importance is conducive to their future development. In this study, a total of 50 Landsat 8 operational land imager(OLI) images were used to analyze the geological features and spectral characteristics of the Nansha reefs. The exposed islands/sandbanks,reef flats and sub-tidal reefs were identified with the near-infrared band, the red and green bands, and the blue band, respectively. Based on the relationships among various characteristics and bands illustrated in the OLI images, the maximum between-cluster variance threshold algorithm(OTSU method) and the mathematical morphology were employed to extract characteristic parameters of the spatial geometry of the reefs from top to bottom, which were subsequently operated by a series of post-processing methods such as vectorization,simplification and topological analysis. Among the 132 standalone reefs and 16 atolls that are identified in the study, four reefs have yet to be named in the Standard Names of Various Islands in the South China Sea and the website Nansha Islands Online(http://www.nansha.org/). Another 24 ones are exposed to the atmosphere even during high tides. Taiping Island with an area of 0.57 km^2 represents the largest exposed geological feature. This study demonstrated the applicability of medium-resolution satellite images to derive the coral reef information effectively and thus provided information for the related departments that are responsible to manage the coast.An improved resolution of multispectral bands with the panchromatic band in higher spatial resolution(15 m for OLI image) is expected to provide an optimum satellite based approach to map marine habitats.展开更多
It is exceedingly important to estimate the stability of coral reefs. In recent years, growing construction projects have been carried out on the reef flat in the South China Sea. As a special marine geotechnical medi...It is exceedingly important to estimate the stability of coral reefs. In recent years, growing construction projects have been carried out on the reef flat in the South China Sea. As a special marine geotechnical medium, it is made of the reef debris underwent overwhelmingly long geological age. Reefs grow thickly on the carbonate platform after the Late Oligocene and have five to six main sedimentary facies. It can be used as a recorder to measure the occurrence time of recent earthquake. A model of reef body is presented to study the influence of earthquakes according to the geological structure characteristic of reefs in the Nansha Islands. Furthermore, Geo Studio is used to simulate stress and deformation situations within it under various earthquake intensities. A safety factor is calculated by the limit equilibrium method, and the possible scenarios of earthquake-induced landslides and sliding scale are defined with a Newmark sliding block method, as well as stress distribution and deformation behaviors. Therefore, the numerical results suggest that the connections between the coral reef and the earthquake are as follows:(1) the reef body has a good stability under self-gravity state;(2) after the earthquake, it may cause slope's instability and bring out slumping when the safety factor is smaller than 1(FS〈1);(3) the safety factor decreases with the increasing earthquake intensity, and fluctuates around a particular value after a while;and(4) as a new developed part of the reef, the smaller shallow landslide will be easily subject to collapse caused by the earthquake. It is concluded that it is feasible to provide a reference for evaluating the stability of coral reef using a geotechnical engineering simulation method. This can help the engineering constructions in the South China Sea.展开更多
The Nansha Islands, China, have extremely high marine biodiversity and hundreds of mollusks have been reported there. Benthos resources investigations of the intertidal and subtidal zone around the Nansha Islands have...The Nansha Islands, China, have extremely high marine biodiversity and hundreds of mollusks have been reported there. Benthos resources investigations of the intertidal and subtidal zone around the Nansha Islands have been continuously performed for decades, and recently, dozens of new species and new records of mollusks have been reported from this area. This paper dealt with three new record species of the Gastropoda from Chinese waters: Cerithium salebrosum Sowerby II, 1855, Vexillum militare(Reeve, 1845) and Vexillum bizonale(Dautzenberg et Bouge, 1923), respectively belonging to three families: Cerithiidae Fleming, 1822, and Costellariidae Mac Donald, 1860. All specimens were collected from the Nansha Islands during the benthos resources investigations on the intertidal zone of islands and reefs in the South China Sea in recent years. Diagnosis and geographic descriptions of both genus and species, illustrations of each species were given in this contribution, and discussion of taxonomy, identification features and faunal characteristics were presented. All examined specimens were deposited in the Marine Biodiversity Collections of South China Sea, Chinese Academy of Sciences.展开更多
Qwing to the unique environments,rich marine resources, monsoon climate and ocean current, the Chinese fishennen from Hainan and Guangdong came to the Nansha Islands 2000 years ago. They have kept engnging in the deve...Qwing to the unique environments,rich marine resources, monsoon climate and ocean current, the Chinese fishennen from Hainan and Guangdong came to the Nansha Islands 2000 years ago. They have kept engnging in the developmen of production since then. The rich historical records and a lot of cultural relics have proved this.展开更多
Ths paper proves that it is the Chinese people that are the eariiest to discover the Nansha Islands in history, according to the irrefdsble facts from historical records, mpaphical discovenes, the opening of sailing l...Ths paper proves that it is the Chinese people that are the eariiest to discover the Nansha Islands in history, according to the irrefdsble facts from historical records, mpaphical discovenes, the opening of sailing lines and the nandng of places.展开更多
Observation data from a cruise in the Nansha Islands, in May to June 1990, December, 1993, September to October 1994, and July, 1999, respectively, were used to develop the method presented here to indicate the existi...Observation data from a cruise in the Nansha Islands, in May to June 1990, December, 1993, September to October 1994, and July, 1999, respectively, were used to develop the method presented here to indicate the existing strength of the dissolved oxygen maximum in the vertical distribution of Nansha Islands waters. Its seasonal variation and regional distribution are discussed in this paper. Analysis results showed that the distribution of the strength of dissolved oxygen maximum (DO max -DO sur ) was closely related to the upper layer circulation and the bioactivity of Nansha Islands seawater.展开更多
Based on the survey data from the program Multidisciplinary Expedition to Nansha Islands Sea Area, the distribution of dissolved inorganic phosphate ( PO43--P ) in the sea water of Nansha Islands Sea Area is comprehen...Based on the survey data from the program Multidisciplinary Expedition to Nansha Islands Sea Area, the distribution of dissolved inorganic phosphate ( PO43--P ) in the sea water of Nansha Islands Sea Area is comprehensively analyzed in this paper. The results show that PO43--P concentration in the sea water of southeastern Nansha Islands Sea Area is commonly higher than that in the other sea areas; the vertical distribution of PO43--P concentration varies inconspicuously in different seasons; the concentration of PO43--P increases with water depth and changes most greatly in the layer of 50 ~ 100 m. The diurnal variation of PO43--P concentration differs in different seasons and at different observation stations. The distribution and variation of PO43--P concentration result from the physical and biological processes together.展开更多
Concentrations of organic matter, iron and manganese in the deep sea surface sediments in the Nansha Islands sea area, South China Sea are measured. Horizontal and vertical distributions of iron and manganese are disc...Concentrations of organic matter, iron and manganese in the deep sea surface sediments in the Nansha Islands sea area, South China Sea are measured. Horizontal and vertical distributions of iron and manganese are discussed. The vertical distribution of iron and manganese in the sediments results from reduction, diffusion, and redeposition of manganese (or iron) oxide and hydroxide in the sediment. There are the maxima of iron and manganese in solid phase in the top of the sediment, which is caused by the penetration of O2 and the upward flux of Mn2+ ( or Fe2+ ). Manganese bacteria play a very important role in the cycle of solid-phase iron and manganese in the ocean environment. Manganese bacteria oxidize Mn2+ ( or Fe2+ ) in dissolved state to Mn4+ ( or Fe3+ ) in oxidized state under the aerobic condition, whereas they reduce iron and manganese in anaerobic conditions.展开更多
The diffusion attenuation coefficient for downwelling irradiance, Kd (490), is an important optical parameter of seawater. The optical property, Kd (490), around Nansha Islands in the South China Sea was analyzed base...The diffusion attenuation coefficient for downwelling irradiance, Kd (490), is an important optical parameter of seawater. The optical property, Kd (490), around Nansha Islands in the South China Sea was analyzed based on optical data profiles measured with SPMR ( SeaWiFS Profiling Multichannel Radiometer ) and SMSR ( SeaWiFS Multichannel Surface Reference ) instrument in April and May, 1999. The results show that Kd (490) is closely correlated with chlorophyll-a concentration, Cchl.a, and that the vertical distribution of Kd (490) shows the strong stratification of the water column in this area. Kd (490) has a similar vertical co-variation as KL (490), the diffusive attenuation coefficient for upwelling radiance. Both coefficients increase with depth in the upper layer, where KL (490) is greater than Kd (490); and after a depth, approximatively at the chlorophyll maximum, they decrease with depth, with the former being smaller than the latter.展开更多
Effective occupation is a key step for a State to acquire, in accordance with the occupation principle of international law, sovereignty over a territory. In case of a remote, desolate and unlivable territory, the req...Effective occupation is a key step for a State to acquire, in accordance with the occupation principle of international law, sovereignty over a territory. In case of a remote, desolate and unlivable territory, the requirements for effective occupation could be lowered appropriately; it is enough if the occupying State exercises or displays acts of sovereignty appropriate to the circumstances of the territory. The Nansha Islands of China is far away from Chinese mainland, and the natural conditions there are harsh. Ever since ancient times, fishery exploitation has been used by China as one of the most important ways to develop and administrate the Nansha Islands. The fishery history of the Nansha Islands not only demonstrates that China, while exploring and exploiting fishery resources, first discovered the Nansha Islands, but also substantiates that China has exercised jurisdiction over this group of islands appropriate to its circumstances, with a view to managing the local fishing activities. Therefore, China has effectively occupied the Nansha Islands, and enjoys the sovereignty over it.展开更多
A reduced vertically integrated upper mixed layer model is set up to numerically study the thermodynamic process of the formation of the 'Nansha warm water'(NWW) in the Nansha Islands sea areas in spring. Acco...A reduced vertically integrated upper mixed layer model is set up to numerically study the thermodynamic process of the formation of the 'Nansha warm water'(NWW) in the Nansha Islands sea areas in spring. According to the numerical experiments, it is shown that, in spring, the formation of the NWW is mainly due to the sea surface net heat flux and the local weak current strength; the contribution from temperature advection transport and warm water exchange with the outer seas (Sulu Sea or south of Sunda shelf) is very little. In the sea areas where the current is strong, the advection may also play an important role in the temperature field.展开更多
Based on the Nansha coral islets and reef's time-space attributes,and the intension and extension of the remote sensing information, the concept model and concept system of coral islets and reef are proposed.Then ...Based on the Nansha coral islets and reef's time-space attributes,and the intension and extension of the remote sensing information, the concept model and concept system of coral islets and reef are proposed.Then twin-tree remote sensing information model for different kinds of reef is constructed by using abstracted islets and reef's primitive, and the structure recognition system for coral islets and reef type is developed.展开更多
In the viempint that the coral reef atolls' growth index of the Nansha Islands is influenced by many factors, the measured remote sensing comopite information including some mutually related factors is divided int...In the viempint that the coral reef atolls' growth index of the Nansha Islands is influenced by many factors, the measured remote sensing comopite information including some mutually related factors is divided into 10 geographic events as N1, N2 ..., N10, and the analysis of the atolls' information entropy is made. From the value of theentropy, the closed related factors with the index of the emerged atolls are shown. In proper order, the factors are reeftop's area(0. 319), lagoon's area(0. 324), open-degree of atoll(0. 336), trend of atoll(0. 551 ). On the basis of thiswork, a new description function of the emerged atoll growth index is proposed. This function can be used to identifythe open my of Nansha atoll growth.展开更多
Russia-Japan and China-Japan Island Disputes have gradually garnered attention as the top hot spot in Northeast Asia. The Japanese government's claim of"nationalization" of Diaoyu Island is worsening the tensions i...Russia-Japan and China-Japan Island Disputes have gradually garnered attention as the top hot spot in Northeast Asia. The Japanese government's claim of"nationalization" of Diaoyu Island is worsening the tensions in China and Japan's economic and trade cooperation, the exchange of personnel and politics and military fields. Approaching the issue from the perspective of the international system evolution can provide us a new way of solving the problem. Because of the unsettlement of the new intemational system, shelving disputes is the most feasible approach.展开更多
The corrosion behavior of pure copper exposed to the atmosphere of Nansha Islands for 21 months was studied by mass loss method,composition analysis,morphology observation and electrochemical measurements.The results ...The corrosion behavior of pure copper exposed to the atmosphere of Nansha Islands for 21 months was studied by mass loss method,composition analysis,morphology observation and electrochemical measurements.The results showed that the average corrosion rate of copper exposed for one year was approximately 7.85μm/a,implying that Nansha Islands was classified as a corrosion category of CX.The structure and properties of the corrosion product layer generated on the front and back sides of the exposed sample differed significantly.The inner corrosion product layer(Cu2O)on the front side was relatively thick and dense,whereas the outer product layer(Cu2Cl(OH)3)was extremely thin.However,the outer product layer on the back side was thicker than the inner layer.Electrochemical measurements indicated that the protection afforded by the corrosion product layer on the front side was improved gradually,while that on the back side was deteriorated.展开更多
The corrosion and pitting behavior of pure aluminum 1060 exposed to Nansha Islands marine atmosphere for 34 months was investigated based on mass loss measurement,scanning electron microscopy(SEM),energy dispersive sp...The corrosion and pitting behavior of pure aluminum 1060 exposed to Nansha Islands marine atmosphere for 34 months was investigated based on mass loss measurement,scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),X-ray photoelectron spectroscopy(XPS),and electrochemical impedance spectroscopy(EIS).The results indicated that serious pitting corrosion occurred on the surfaces of pure aluminum.The corrosion rate after exposure for 13 months was approximately 1.28 g/(m^(2)·a).The XPS results showed that the corrosion products were Al_(2)O_(3),Al(OH)_(3),and AlCl_(3).Moreover,the corrosion product layer was more protective than the native oxide film,and the protectiveness first increased and then decreased.Finally,the shape of the pits was evaluated using statistical analysis.展开更多
基金Under the auspices of National Key Research and Development Program of China (No.2022YFC3103103)。
文摘Changes in vegetation status generally also represents changes in the ecological health of islands and reefs(IRs).However,studies are limited of drivers and trends of vegetation change of Nansha Islands,China and how they relate to climate change and human activities.To resolve this limitation,we studied changes to the Normalized Difference Vegetation Index(NDVI)vegetation-greenness index for 22 IRs of Nansha Islands during normal and extreme conditions.Trends of vegetation greenness were analyzed using Sen's slope and Mann-Kendall test at two spatial scales(pixel and island),and driving factor analyses were performed by time-lagged partial correlation analyses.These were related to impacts from human activities and climatic factors under normal(temperature,precipitation,radiation,and Normalized Difference Built-up Index(NDBI))and extreme conditions(wind speed and latitude of IRs)from 2016 to 2022.Results showed:1)among the 22 IRs,NDVI increased/decreased significantly in 15/4 IRs,respectively.Huayang Reef had the highest NDVI change-rate(0.48%/mon),and Zhongye Island had the lowest(–0.29%/mon).Local spatial patterns were in one of two forms:dotted-form,and degradation in banded-form.2)Under normal conditions,human activities(characterized by NDBI)had higher impacts on vegetation-greenness than other factors.3)Under extreme conditions,wind speed(R^(2)=0.2337,P<0.05)and latitude(R^(2)=0.2769,P<0.05)provided limited explanation for changes from typhoon events.Our results provide scientific support for the sustainable development of Nansha Islands and the United Nations‘Ocean Decade’initiative.
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.
文摘Dynamics of major picoplankton groups, Synechococcus (Syn), Prochlorococcus (Pro), picoeukaryotes (Euk) and heterotrophic bacteria (Bact) was investigated by flow cytometry for the first time in the Nansha Islands area in the South China Sea. Averaged over the whole investigation area, depth-weighted integrated cell abundance (DWA) of Syn, Pro, Euk and Bact was 1.6 (0.4-5.7)×103, 5.4 (0.1-7.3)×104, 0.7 (0.2-2.2)×103, and 2.3 (1.4-3.2)×105 cells/mL respectively. Picoautotrophic cell abundance was low in the northwest part of the Nansha Islands where surface water temperature was low and the upper mixed layer was shallow. Concurrently, a surface maximum vertical distribution pattern was observed in this area. While in the southeast and east zones where temperatures were relatively higher and nitraclines were deeper, picoplankton is abundant and a subsurface maximum around 50-75 m is observed. Coupling of horizontal and vertical distribution patterns of picoplankton abundance and hydrological status was found, suggesting a strong influence of currents and water column structure on picoplankton distribution in the investigation area. Contrary to that in the shelf water in the East China Sea, the relationship between Pro and Bact in the Nansha Islands area in the South China Sea was not significantly negative but weakly positive. Moreover, a similar distribution pattern of Syn and Pro was observed. Possible reasons for these differences in the two marine regimes were discussed.
基金The National High Technology Research and Development Program of China(863 Program)under contract No.2012AA12A406the National Natural Science Foundation of China under contract Nos 41471068,41171325,and J1103408+1 种基金the Program for New Century Excellent Talents in University under contract No.NCET-12-0264the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘A detailed survey of the reefs in the Nansha Islands' sea that are of strategic importance is conducive to their future development. In this study, a total of 50 Landsat 8 operational land imager(OLI) images were used to analyze the geological features and spectral characteristics of the Nansha reefs. The exposed islands/sandbanks,reef flats and sub-tidal reefs were identified with the near-infrared band, the red and green bands, and the blue band, respectively. Based on the relationships among various characteristics and bands illustrated in the OLI images, the maximum between-cluster variance threshold algorithm(OTSU method) and the mathematical morphology were employed to extract characteristic parameters of the spatial geometry of the reefs from top to bottom, which were subsequently operated by a series of post-processing methods such as vectorization,simplification and topological analysis. Among the 132 standalone reefs and 16 atolls that are identified in the study, four reefs have yet to be named in the Standard Names of Various Islands in the South China Sea and the website Nansha Islands Online(http://www.nansha.org/). Another 24 ones are exposed to the atmosphere even during high tides. Taiping Island with an area of 0.57 km^2 represents the largest exposed geological feature. This study demonstrated the applicability of medium-resolution satellite images to derive the coral reef information effectively and thus provided information for the related departments that are responsible to manage the coast.An improved resolution of multispectral bands with the panchromatic band in higher spatial resolution(15 m for OLI image) is expected to provide an optimum satellite based approach to map marine habitats.
基金The National Basic Research Program(973 Program)of China under contract No.2013CB956104the National Natural Science Foundation of China under contract No.41376063the Strategic Priority Research Program of the Chinese Academy of Sciences under contract No.XDA13000000
文摘It is exceedingly important to estimate the stability of coral reefs. In recent years, growing construction projects have been carried out on the reef flat in the South China Sea. As a special marine geotechnical medium, it is made of the reef debris underwent overwhelmingly long geological age. Reefs grow thickly on the carbonate platform after the Late Oligocene and have five to six main sedimentary facies. It can be used as a recorder to measure the occurrence time of recent earthquake. A model of reef body is presented to study the influence of earthquakes according to the geological structure characteristic of reefs in the Nansha Islands. Furthermore, Geo Studio is used to simulate stress and deformation situations within it under various earthquake intensities. A safety factor is calculated by the limit equilibrium method, and the possible scenarios of earthquake-induced landslides and sliding scale are defined with a Newmark sliding block method, as well as stress distribution and deformation behaviors. Therefore, the numerical results suggest that the connections between the coral reef and the earthquake are as follows:(1) the reef body has a good stability under self-gravity state;(2) after the earthquake, it may cause slope's instability and bring out slumping when the safety factor is smaller than 1(FS〈1);(3) the safety factor decreases with the increasing earthquake intensity, and fluctuates around a particular value after a while;and(4) as a new developed part of the reef, the smaller shallow landslide will be easily subject to collapse caused by the earthquake. It is concluded that it is feasible to provide a reference for evaluating the stability of coral reef using a geotechnical engineering simulation method. This can help the engineering constructions in the South China Sea.
基金supported by the National Natural Science Foundation of China (No.41406185)the Special Funds for the Young Scholars of Taxonomy of the Chinese Academy of Sciences (No.ZSBR-010)the Special Program for Basic Research of the Ministry of Science and Technology,China (No.2012FY112400,No.2013FY111200)
文摘The Nansha Islands, China, have extremely high marine biodiversity and hundreds of mollusks have been reported there. Benthos resources investigations of the intertidal and subtidal zone around the Nansha Islands have been continuously performed for decades, and recently, dozens of new species and new records of mollusks have been reported from this area. This paper dealt with three new record species of the Gastropoda from Chinese waters: Cerithium salebrosum Sowerby II, 1855, Vexillum militare(Reeve, 1845) and Vexillum bizonale(Dautzenberg et Bouge, 1923), respectively belonging to three families: Cerithiidae Fleming, 1822, and Costellariidae Mac Donald, 1860. All specimens were collected from the Nansha Islands during the benthos resources investigations on the intertidal zone of islands and reefs in the South China Sea in recent years. Diagnosis and geographic descriptions of both genus and species, illustrations of each species were given in this contribution, and discussion of taxonomy, identification features and faunal characteristics were presented. All examined specimens were deposited in the Marine Biodiversity Collections of South China Sea, Chinese Academy of Sciences.
文摘Qwing to the unique environments,rich marine resources, monsoon climate and ocean current, the Chinese fishennen from Hainan and Guangdong came to the Nansha Islands 2000 years ago. They have kept engnging in the developmen of production since then. The rich historical records and a lot of cultural relics have proved this.
文摘Ths paper proves that it is the Chinese people that are the eariiest to discover the Nansha Islands in history, according to the irrefdsble facts from historical records, mpaphical discovenes, the opening of sailing lines and the nandng of places.
文摘Observation data from a cruise in the Nansha Islands, in May to June 1990, December, 1993, September to October 1994, and July, 1999, respectively, were used to develop the method presented here to indicate the existing strength of the dissolved oxygen maximum in the vertical distribution of Nansha Islands waters. Its seasonal variation and regional distribution are discussed in this paper. Analysis results showed that the distribution of the strength of dissolved oxygen maximum (DO max -DO sur ) was closely related to the upper layer circulation and the bioactivity of Nansha Islands seawater.
文摘Based on the survey data from the program Multidisciplinary Expedition to Nansha Islands Sea Area, the distribution of dissolved inorganic phosphate ( PO43--P ) in the sea water of Nansha Islands Sea Area is comprehensively analyzed in this paper. The results show that PO43--P concentration in the sea water of southeastern Nansha Islands Sea Area is commonly higher than that in the other sea areas; the vertical distribution of PO43--P concentration varies inconspicuously in different seasons; the concentration of PO43--P increases with water depth and changes most greatly in the layer of 50 ~ 100 m. The diurnal variation of PO43--P concentration differs in different seasons and at different observation stations. The distribution and variation of PO43--P concentration result from the physical and biological processes together.
基金supported by the National Natural Science Foundation of China(contract No.49706065)the Special Foundation of National Social Common Wealth Research(contract No.2001DIA50041)ZKCX2-SW-212 by Chinese Academy of Science
文摘Concentrations of organic matter, iron and manganese in the deep sea surface sediments in the Nansha Islands sea area, South China Sea are measured. Horizontal and vertical distributions of iron and manganese are discussed. The vertical distribution of iron and manganese in the sediments results from reduction, diffusion, and redeposition of manganese (or iron) oxide and hydroxide in the sediment. There are the maxima of iron and manganese in solid phase in the top of the sediment, which is caused by the penetration of O2 and the upward flux of Mn2+ ( or Fe2+ ). Manganese bacteria play a very important role in the cycle of solid-phase iron and manganese in the ocean environment. Manganese bacteria oxidize Mn2+ ( or Fe2+ ) in dissolved state to Mn4+ ( or Fe3+ ) in oxidized state under the aerobic condition, whereas they reduce iron and manganese in anaerobic conditions.
基金This work was jointly supported by project KZCX2-202 from CAS the project of 818-06-03 from national 863 program and project 97-926-07 of national special program for science and technology.
文摘The diffusion attenuation coefficient for downwelling irradiance, Kd (490), is an important optical parameter of seawater. The optical property, Kd (490), around Nansha Islands in the South China Sea was analyzed based on optical data profiles measured with SPMR ( SeaWiFS Profiling Multichannel Radiometer ) and SMSR ( SeaWiFS Multichannel Surface Reference ) instrument in April and May, 1999. The results show that Kd (490) is closely correlated with chlorophyll-a concentration, Cchl.a, and that the vertical distribution of Kd (490) shows the strong stratification of the water column in this area. Kd (490) has a similar vertical co-variation as KL (490), the diffusive attenuation coefficient for upwelling radiance. Both coefficients increase with depth in the upper layer, where KL (490) is greater than Kd (490); and after a depth, approximatively at the chlorophyll maximum, they decrease with depth, with the former being smaller than the latter.
文摘Effective occupation is a key step for a State to acquire, in accordance with the occupation principle of international law, sovereignty over a territory. In case of a remote, desolate and unlivable territory, the requirements for effective occupation could be lowered appropriately; it is enough if the occupying State exercises or displays acts of sovereignty appropriate to the circumstances of the territory. The Nansha Islands of China is far away from Chinese mainland, and the natural conditions there are harsh. Ever since ancient times, fishery exploitation has been used by China as one of the most important ways to develop and administrate the Nansha Islands. The fishery history of the Nansha Islands not only demonstrates that China, while exploring and exploiting fishery resources, first discovered the Nansha Islands, but also substantiates that China has exercised jurisdiction over this group of islands appropriate to its circumstances, with a view to managing the local fishing activities. Therefore, China has effectively occupied the Nansha Islands, and enjoys the sovereignty over it.
基金This work was supported by the Knowledge Innovation Frontier Project of South China Sea Institute of OceanologyChinese Academy of Sciences under contract No,LYQY200310+1 种基金National Science Foundation of China under contract Nos 40376003 and 40276004 National Special Key Project of China under contract No.2001DIA50041.
文摘A reduced vertically integrated upper mixed layer model is set up to numerically study the thermodynamic process of the formation of the 'Nansha warm water'(NWW) in the Nansha Islands sea areas in spring. According to the numerical experiments, it is shown that, in spring, the formation of the NWW is mainly due to the sea surface net heat flux and the local weak current strength; the contribution from temperature advection transport and warm water exchange with the outer seas (Sulu Sea or south of Sunda shelf) is very little. In the sea areas where the current is strong, the advection may also play an important role in the temperature field.
文摘Based on the Nansha coral islets and reef's time-space attributes,and the intension and extension of the remote sensing information, the concept model and concept system of coral islets and reef are proposed.Then twin-tree remote sensing information model for different kinds of reef is constructed by using abstracted islets and reef's primitive, and the structure recognition system for coral islets and reef type is developed.
文摘In the viempint that the coral reef atolls' growth index of the Nansha Islands is influenced by many factors, the measured remote sensing comopite information including some mutually related factors is divided into 10 geographic events as N1, N2 ..., N10, and the analysis of the atolls' information entropy is made. From the value of theentropy, the closed related factors with the index of the emerged atolls are shown. In proper order, the factors are reeftop's area(0. 319), lagoon's area(0. 324), open-degree of atoll(0. 336), trend of atoll(0. 551 ). On the basis of thiswork, a new description function of the emerged atoll growth index is proposed. This function can be used to identifythe open my of Nansha atoll growth.
文摘Russia-Japan and China-Japan Island Disputes have gradually garnered attention as the top hot spot in Northeast Asia. The Japanese government's claim of"nationalization" of Diaoyu Island is worsening the tensions in China and Japan's economic and trade cooperation, the exchange of personnel and politics and military fields. Approaching the issue from the perspective of the international system evolution can provide us a new way of solving the problem. Because of the unsettlement of the new intemational system, shelving disputes is the most feasible approach.
基金The authors are grateful for the financial supports from National Natural Science Foundation of China(51671197)Strategic Priority Research Program of Chinese Academy of Sciences(13040502).
文摘The corrosion behavior of pure copper exposed to the atmosphere of Nansha Islands for 21 months was studied by mass loss method,composition analysis,morphology observation and electrochemical measurements.The results showed that the average corrosion rate of copper exposed for one year was approximately 7.85μm/a,implying that Nansha Islands was classified as a corrosion category of CX.The structure and properties of the corrosion product layer generated on the front and back sides of the exposed sample differed significantly.The inner corrosion product layer(Cu2O)on the front side was relatively thick and dense,whereas the outer product layer(Cu2Cl(OH)3)was extremely thin.However,the outer product layer on the back side was thicker than the inner layer.Electrochemical measurements indicated that the protection afforded by the corrosion product layer on the front side was improved gradually,while that on the back side was deteriorated.
基金the National Natural Science Foundation of China(No.51671197)Special Project of Chinese Academy of Sciences(No.XDA130040502).
文摘The corrosion and pitting behavior of pure aluminum 1060 exposed to Nansha Islands marine atmosphere for 34 months was investigated based on mass loss measurement,scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),X-ray photoelectron spectroscopy(XPS),and electrochemical impedance spectroscopy(EIS).The results indicated that serious pitting corrosion occurred on the surfaces of pure aluminum.The corrosion rate after exposure for 13 months was approximately 1.28 g/(m^(2)·a).The XPS results showed that the corrosion products were Al_(2)O_(3),Al(OH)_(3),and AlCl_(3).Moreover,the corrosion product layer was more protective than the native oxide film,and the protectiveness first increased and then decreased.Finally,the shape of the pits was evaluated using statistical analysis.