The content and distribution of biogenic silica were investigated in sediment cores from Prydz Bay, Antarctica, during the CHINARE-18/2L cruise. The results show that the content of biogenic silica（ BSiO2 ） is range...The content and distribution of biogenic silica were investigated in sediment cores from Prydz Bay, Antarctica, during the CHINARE-18/2L cruise. The results show that the content of biogenic silica（ BSiO2 ） is ranged from 4.89% to 85. 41% , and the average content of biogenic silica is 30.90%, the highest value oc- curred at the IV-10 station. The profile of BSiO2 in sediment is contrast to that of sili- cate in the interstitial water. The content of biogenic silica and organic carbon in the surface sediments in the central area of Prydz Bay gyre were much higher than those in other area, and closely related to the Chla content and primary productivity of phyto- plankton in the surface water column.展开更多
Surface sediments from the Chukchi Sea and adjacent arctic deep sea were investigated for organic carbon and nitrogen isotopes （in δ13Corg and δ15Norg） as well as biogeni＇c silica （BSiO2）. δ13Corg and δ15Norg...Surface sediments from the Chukchi Sea and adjacent arctic deep sea were investigated for organic carbon and nitrogen isotopes （in δ13Corg and δ15Norg） as well as biogeni＇c silica （BSiO2）. δ13Corg and δ15Norg values of surface sediments in the study area fall between the end-member values of marine and terrestrial organic matter from the surrounding lands and seas, their variations reflect the changes of marine productivity and terrestrial supply in the study area. BSiO2 shows a similar distribution pattern with δ13Corg and δ15Norg, and can be used as an indicator of marine productivity. In the central-west Chukchi Sea and the Chukchi Rise, sediments have higher δ13Corg, δ15Norg and BSiO2 values, indicating the region has high marine productivity influenced by the nutrient-rich branches of the Pacific waters. In the coastal zone off northwestern Alaska, δ13Corg and δ15Norg values become lighter, indicating a weakening marine productivity and an increasing terrigenous supply due to the effects of the least nutrient-rich branch of the Pacific waters. In the north and the northeast of the study area （including the Chukchi Plateau, the Canada Basin and the Beaufort shelf）, δ13Corg, δ15Norg and BSiO2 have the lowest values, and the terrigenous organic matter becomes dominant in surface sediments because this region has the longest ice-covered duration, the least nutrient-rich seawater and the increasing supply of terrestrial materials from the Mackenzie River and the northern Alaska under the action of the clockwise Beaufort gyre. Because the subarctic Pacific waters are continuously discharged into the central basin of the Arctic Ocean through the study area, the nutrient pool in the Chukchi Sea can be considered as a typical open system, the ratio of δ15Norg to BSiO2 content show some tracers that the level of nutrient utilization is contrary to nutrient supply and marine productivity formed in seawater.展开更多
基金funded by the:"National Key Technology R&D Program project (2006BAB18B04)","The scientific research fund of the Second Institute of Oceanography,SOA (JT0706)",Polar stratagem fund"The mechanism of biogenic silica Preservation in the Prydz Bay and its biogeochemical significance"
文摘The content and distribution of biogenic silica were investigated in sediment cores from Prydz Bay, Antarctica, during the CHINARE-18/2L cruise. The results show that the content of biogenic silica（ BSiO2 ） is ranged from 4.89% to 85. 41% , and the average content of biogenic silica is 30.90%, the highest value oc- curred at the IV-10 station. The profile of BSiO2 in sediment is contrast to that of sili- cate in the interstitial water. The content of biogenic silica and organic carbon in the surface sediments in the central area of Prydz Bay gyre were much higher than those in other area, and closely related to the Chla content and primary productivity of phyto- plankton in the surface water column.
基金the National Natural Science Foundation of China under contract Nos 40506004 and 40431002.
文摘Surface sediments from the Chukchi Sea and adjacent arctic deep sea were investigated for organic carbon and nitrogen isotopes （in δ13Corg and δ15Norg） as well as biogeni＇c silica （BSiO2）. δ13Corg and δ15Norg values of surface sediments in the study area fall between the end-member values of marine and terrestrial organic matter from the surrounding lands and seas, their variations reflect the changes of marine productivity and terrestrial supply in the study area. BSiO2 shows a similar distribution pattern with δ13Corg and δ15Norg, and can be used as an indicator of marine productivity. In the central-west Chukchi Sea and the Chukchi Rise, sediments have higher δ13Corg, δ15Norg and BSiO2 values, indicating the region has high marine productivity influenced by the nutrient-rich branches of the Pacific waters. In the coastal zone off northwestern Alaska, δ13Corg and δ15Norg values become lighter, indicating a weakening marine productivity and an increasing terrigenous supply due to the effects of the least nutrient-rich branch of the Pacific waters. In the north and the northeast of the study area （including the Chukchi Plateau, the Canada Basin and the Beaufort shelf）, δ13Corg, δ15Norg and BSiO2 have the lowest values, and the terrigenous organic matter becomes dominant in surface sediments because this region has the longest ice-covered duration, the least nutrient-rich seawater and the increasing supply of terrestrial materials from the Mackenzie River and the northern Alaska under the action of the clockwise Beaufort gyre. Because the subarctic Pacific waters are continuously discharged into the central basin of the Arctic Ocean through the study area, the nutrient pool in the Chukchi Sea can be considered as a typical open system, the ratio of δ15Norg to BSiO2 content show some tracers that the level of nutrient utilization is contrary to nutrient supply and marine productivity formed in seawater.
