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
Based on a data base of multi-channel seismic profiles covered over Dongsha plateau of the northern South China Sea margin, we found that the sea bed morphology of northern South China Sea margin had been changed dram...Based on a data base of multi-channel seismic profiles covered over Dongsha plateau of the northern South China Sea margin, we found that the sea bed morphology of northern South China Sea margin had been changed dramatically after Dongsha uplifting, that sedimentary layer since Miocene age had been eroded with maximum eroded thickness more than 1000 m, and that an erosive channel had been formed of 20 km in width and 200 km in length and several hundreds meters in depth on the outer shelf of northern South China Sea. The erosive channel is parallel to the 600 m isobath line, stretching from northeast to the southwest north of Dongsha uplift. The Kuroshio intrudes the South China Sea through Luzon Strait both in winter time and summer time, and in the northern South China Sea margin area, the intruded Kuroshio Branch takes the form of Pacific-Indian Ocean Through Flow (PITH) in winter time, while the Luzon Strait Subsurface Inflow (LSSIF) in summer time, the routes of both PITH and LSSIF coincide well with the distribution of the erosive channel. After climbing from the northern slope up to the northern shelf, and after joined by the southward flow from the middle northern shelf of South China Sea, the Kuroshio Branch is strengthened and thus is able to erode the sea floor, and the shape of the erosive channel is a result of the long-term interaction between the Kuroshio South China Sea Branch and the Dongsha outer shelf sea floor.展开更多
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supported by National Basic Research Program of China (Grant No. 2007CB411702)
文摘Based on a data base of multi-channel seismic profiles covered over Dongsha plateau of the northern South China Sea margin, we found that the sea bed morphology of northern South China Sea margin had been changed dramatically after Dongsha uplifting, that sedimentary layer since Miocene age had been eroded with maximum eroded thickness more than 1000 m, and that an erosive channel had been formed of 20 km in width and 200 km in length and several hundreds meters in depth on the outer shelf of northern South China Sea. The erosive channel is parallel to the 600 m isobath line, stretching from northeast to the southwest north of Dongsha uplift. The Kuroshio intrudes the South China Sea through Luzon Strait both in winter time and summer time, and in the northern South China Sea margin area, the intruded Kuroshio Branch takes the form of Pacific-Indian Ocean Through Flow (PITH) in winter time, while the Luzon Strait Subsurface Inflow (LSSIF) in summer time, the routes of both PITH and LSSIF coincide well with the distribution of the erosive channel. After climbing from the northern slope up to the northern shelf, and after joined by the southward flow from the middle northern shelf of South China Sea, the Kuroshio Branch is strengthened and thus is able to erode the sea floor, and the shape of the erosive channel is a result of the long-term interaction between the Kuroshio South China Sea Branch and the Dongsha outer shelf sea floor.
