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
This work yielded an improved method for extracting and analysing benzothiophene in marine sediment.The detation limit was 0.05 ng S of benzothiophene, with precision of 8%. Benzothiophene was found in Nansha Islands ...This work yielded an improved method for extracting and analysing benzothiophene in marine sediment.The detation limit was 0.05 ng S of benzothiophene, with precision of 8%. Benzothiophene was found in Nansha Islands sea area sediments and ranged from 1.1 -6.8 ng per gram dry sediment. Its concentration was closely correlated to hte organic carbon content in the sediment.Several source processes of benzohtiophene are discussed in this paper.展开更多
Using P0M97. an oceanic model, we separately do numerical tests to simulate the 3-D struc ture of temperature in the sea area around Taiwan Island with or without effect of Kuroshio (Current). Through contrast analysi...Using P0M97. an oceanic model, we separately do numerical tests to simulate the 3-D struc ture of temperature in the sea area around Taiwan Island with or without effect of Kuroshio (Current). Through contrast analysis. we find that inflow of Kuroshio results in winter mean water temperature of sub-surface layer in the whole sea regions raising 5 - 6℃ more than that without effect of Kuroshio. The existence of Kuroshio does important role on oceanic thermocline of deep water area in the east of Taiwan Island, and has some effect on intensity of seasonal thermocline of Taiwan Strait and its southern shallow water area.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
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
A modified inverse method is used to compute the circulations east of Taiwan and in the East China Sec and east of the Ryukyu Islands with hydrographic data obtained during early summer of 1985. The computational regi...A modified inverse method is used to compute the circulations east of Taiwan and in the East China Sec and east of the Ryukyu Islands with hydrographic data obtained during early summer of 1985. The computational region covers an area west of 129°E and from 21°45'N to 35°N. The computed results show that: (1 ) The net volume transport (VT ) of the Kuroshio through 21°45'N Section east of Ta Taiwan and west of 123°E is about 45 × 10￣6 m￣3/sduring early summer of 1985. The Kuroshio has. two current cores. One is located near Taiwan, and its velocity isvery large and its maximum velocity is 226 cm/s at the 100 m level, which is close to the maximum velocity of the beginning of the Kuroshio east of the Philippines. The other is located further to the east, and its maximum velocity is159 cm/s at the 100m level; (2) through a transect northwest Of Miyakojima Island and a transect southwest of Okinawa laaed the volume transports of the Kuroshio in the East China Sea both are about 25 × 10￣6 m￣3/s. The maximumvelocity of the Kuroshio at these two sections is 194 and 128 cm/s, respectively, and both are located on the shelfbreak; (3) beneath and east of the Kurohio there are the countercurrent (4) southeast of Okinawa Island there is anortheastward current, and its VT at Section HI is about 12. 6 × 10￣6 m￣3/s, and it comes from a westward flow at 129° This project was supported by the National Natural Science Foundation of China under contract No. 49476278.(Second Institute of Oceanography, State Oceanic Administration, Hongzhou310012, China) (Institute of Oceanography, Taiwan University, Taipei, China)E Section and the recirculating gyre, and does not originate from the Kuroshio east of Taiwan during early summer of 1985. There is a southwestward abyssal current east of Okinawa Islands (5) there are several different scale eddies in this computational region. For example, there is a meso-scale strong cyclonic eddy east of Miyakojima Island.展开更多
Islands and the mainland are separated by seas,and the distances between them might be so long that the height on the mainland cannot be exactly translated to the islands,resulting in different height systems on the m...Islands and the mainland are separated by seas,and the distances between them might be so long that the height on the mainland cannot be exactly translated to the islands,resulting in different height systems on the mainland and the islands.In this study,we used astrogeodetic deflections of the vertical and ellipsoidal heights of points on the mainland and island near their coastlines to implement height connection across sea areas.First,the modeled gravity and modeled astrogeodetic vertical deflections of segmentation points along connecting routes over the sea between the mainland and the island were determined by Earth Gravity Model(EGM),and the ellipsoidal heights of segmentation points were determined by the satellite altimetry data sets.Second,we used a linear interpolation model to increase the precision of the vertical deflections of segmentation points.Third,we computed the geopotential difference of points between the mainland and the island using a method derived from geopotential theory and the astronomical leveling principle.Finally,we estimated the normal height of the point on the island using the geopotential-difference iterative computation approach.Using observed data of normal heights,ellipsoidal heights,and astrogeodetic vertical deflections referring to height sites in Qingdao,Shandong Province,we conducted a numerical experiment involving the normal height connection across sea regions.We determined the data of the ellipsoidal heights and gravity of segmentation points along the connecting route across the water in the numerical experiment using DTU10.The distance of the height connection across the sea was approximately 10.5 km.According to China's official leveling specifications,the experimental results met the criterion of third-class leveling precision.展开更多
近岸岛屿毗邻海域作为陆架边缘海中最具代表性的区域之一,是重要的海-陆过渡区域。在自然环境变动与人类活动的双重影响下,其生态系统具有多样性和复杂性。长岛毗邻海域具有典型的海岛生态环境特征,为渤黄海渔业种类的洄游通道和关键栖...近岸岛屿毗邻海域作为陆架边缘海中最具代表性的区域之一,是重要的海-陆过渡区域。在自然环境变动与人类活动的双重影响下,其生态系统具有多样性和复杂性。长岛毗邻海域具有典型的海岛生态环境特征,为渤黄海渔业种类的洄游通道和关键栖息地,对该海域生态系统食物网结构和能流过程具有重要意义。2021年3月至12月,山东长岛近海渔业资源国家野外科学观测研究站在长岛毗邻海域开展10航次,每航次10站的底层渔业生物逐月调查与样品测定。通过对渔获物的生物学测定数据进行计算,获得相对重要性指数(index of relative importance,IRI)、物种更替率、单位捕捞努力量渔获量(catch per unit effort,CPUE)以及包含Margalef丰富度指数(D)、Shannon-Wiener多样性指数(H′)和Pielou均匀度指数(J′)在内的生物多样性指数,构成了本数据集。基于多人全样本交叉复核完成审查与校对过程,确保数据集的规范性与准确性。本数据集可为渤黄海底层渔业生物时空格局和海岛生态系统研究提供数据支撑。展开更多
利用Ecopath with Ecosim 6.5(EWE)软件构建了包含17个生态功能组的中街山列岛海域生态模型,在该模型基础上分析研究中街山列岛海域生态系统状况,研究结果表明生态系统中各个功能组的有效营养级在1-4.648之间。中街山列岛海域曼氏无针...利用Ecopath with Ecosim 6.5(EWE)软件构建了包含17个生态功能组的中街山列岛海域生态模型,在该模型基础上分析研究中街山列岛海域生态系统状况,研究结果表明生态系统中各个功能组的有效营养级在1-4.648之间。中街山列岛海域曼氏无针乌贼的营养级为3.562,属于中等营养级。中街山列岛海域功能组的营养转换效率在0.013-0.991之间。结合相关参数评估计算,中街山列岛海域曼氏无针乌贼的生态容量为30.8 t,可增殖放流曼氏无针乌贼受精卵约224 kg。展开更多
Seismic correlation length for moderate earthquakes prior to two great earthquakes in the northern sea area of Sumatra Island （Mw9.1 in 2004 and MsS. 6 in 2012） has been studied, using method of Single- Link-Cluster...Seismic correlation length for moderate earthquakes prior to two great earthquakes in the northern sea area of Sumatra Island （Mw9.1 in 2004 and MsS. 6 in 2012） has been studied, using method of Single- Link-Cluster （ SLC ） analysis, and found to show a power-law growth about two years before their occurrences. No such growth was found for a magnitude 7 earthquake in the same area. This result suggests the occurrence of a physical process of critical-point characteristics in the source area before the great earthquakes.展开更多
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.
文摘This work yielded an improved method for extracting and analysing benzothiophene in marine sediment.The detation limit was 0.05 ng S of benzothiophene, with precision of 8%. Benzothiophene was found in Nansha Islands sea area sediments and ranged from 1.1 -6.8 ng per gram dry sediment. Its concentration was closely correlated to hte organic carbon content in the sediment.Several source processes of benzohtiophene are discussed in this paper.
文摘Using P0M97. an oceanic model, we separately do numerical tests to simulate the 3-D struc ture of temperature in the sea area around Taiwan Island with or without effect of Kuroshio (Current). Through contrast analysis. we find that inflow of Kuroshio results in winter mean water temperature of sub-surface layer in the whole sea regions raising 5 - 6℃ more than that without effect of Kuroshio. The existence of Kuroshio does important role on oceanic thermocline of deep water area in the east of Taiwan Island, and has some effect on intensity of seasonal thermocline of Taiwan Strait and its southern shallow water area.
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.
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.
文摘A modified inverse method is used to compute the circulations east of Taiwan and in the East China Sec and east of the Ryukyu Islands with hydrographic data obtained during early summer of 1985. The computational region covers an area west of 129°E and from 21°45'N to 35°N. The computed results show that: (1 ) The net volume transport (VT ) of the Kuroshio through 21°45'N Section east of Ta Taiwan and west of 123°E is about 45 × 10￣6 m￣3/sduring early summer of 1985. The Kuroshio has. two current cores. One is located near Taiwan, and its velocity isvery large and its maximum velocity is 226 cm/s at the 100 m level, which is close to the maximum velocity of the beginning of the Kuroshio east of the Philippines. The other is located further to the east, and its maximum velocity is159 cm/s at the 100m level; (2) through a transect northwest Of Miyakojima Island and a transect southwest of Okinawa laaed the volume transports of the Kuroshio in the East China Sea both are about 25 × 10￣6 m￣3/s. The maximumvelocity of the Kuroshio at these two sections is 194 and 128 cm/s, respectively, and both are located on the shelfbreak; (3) beneath and east of the Kurohio there are the countercurrent (4) southeast of Okinawa Island there is anortheastward current, and its VT at Section HI is about 12. 6 × 10￣6 m￣3/s, and it comes from a westward flow at 129° This project was supported by the National Natural Science Foundation of China under contract No. 49476278.(Second Institute of Oceanography, State Oceanic Administration, Hongzhou310012, China) (Institute of Oceanography, Taiwan University, Taipei, China)E Section and the recirculating gyre, and does not originate from the Kuroshio east of Taiwan during early summer of 1985. There is a southwestward abyssal current east of Okinawa Islands (5) there are several different scale eddies in this computational region. For example, there is a meso-scale strong cyclonic eddy east of Miyakojima Island.
基金financially supported by the foundation of the Key Laboratory of Marine Environmental Survey Technology and Application,Ministry of Natural Resources,China (No. MESTA-2020-B006)the National Natural Science Foundation of China (No.41774001)
文摘Islands and the mainland are separated by seas,and the distances between them might be so long that the height on the mainland cannot be exactly translated to the islands,resulting in different height systems on the mainland and the islands.In this study,we used astrogeodetic deflections of the vertical and ellipsoidal heights of points on the mainland and island near their coastlines to implement height connection across sea areas.First,the modeled gravity and modeled astrogeodetic vertical deflections of segmentation points along connecting routes over the sea between the mainland and the island were determined by Earth Gravity Model(EGM),and the ellipsoidal heights of segmentation points were determined by the satellite altimetry data sets.Second,we used a linear interpolation model to increase the precision of the vertical deflections of segmentation points.Third,we computed the geopotential difference of points between the mainland and the island using a method derived from geopotential theory and the astronomical leveling principle.Finally,we estimated the normal height of the point on the island using the geopotential-difference iterative computation approach.Using observed data of normal heights,ellipsoidal heights,and astrogeodetic vertical deflections referring to height sites in Qingdao,Shandong Province,we conducted a numerical experiment involving the normal height connection across sea regions.We determined the data of the ellipsoidal heights and gravity of segmentation points along the connecting route across the water in the numerical experiment using DTU10.The distance of the height connection across the sea was approximately 10.5 km.According to China's official leveling specifications,the experimental results met the criterion of third-class leveling precision.
文摘近岸岛屿毗邻海域作为陆架边缘海中最具代表性的区域之一,是重要的海-陆过渡区域。在自然环境变动与人类活动的双重影响下,其生态系统具有多样性和复杂性。长岛毗邻海域具有典型的海岛生态环境特征,为渤黄海渔业种类的洄游通道和关键栖息地,对该海域生态系统食物网结构和能流过程具有重要意义。2021年3月至12月,山东长岛近海渔业资源国家野外科学观测研究站在长岛毗邻海域开展10航次,每航次10站的底层渔业生物逐月调查与样品测定。通过对渔获物的生物学测定数据进行计算,获得相对重要性指数(index of relative importance,IRI)、物种更替率、单位捕捞努力量渔获量(catch per unit effort,CPUE)以及包含Margalef丰富度指数(D)、Shannon-Wiener多样性指数(H′)和Pielou均匀度指数(J′)在内的生物多样性指数,构成了本数据集。基于多人全样本交叉复核完成审查与校对过程,确保数据集的规范性与准确性。本数据集可为渤黄海底层渔业生物时空格局和海岛生态系统研究提供数据支撑。
文摘Seismic correlation length for moderate earthquakes prior to two great earthquakes in the northern sea area of Sumatra Island （Mw9.1 in 2004 and MsS. 6 in 2012） has been studied, using method of Single- Link-Cluster （ SLC ） analysis, and found to show a power-law growth about two years before their occurrences. No such growth was found for a magnitude 7 earthquake in the same area. This result suggests the occurrence of a physical process of critical-point characteristics in the source area before the great earthquakes.
