Responses of Primary Productivity to Current and Climate Changes in the Mud Area to the Southwest of Cheju Island During the Past 800 Years  

作　　者：LIU Yi ZHOU Xin HUANG Wen WANG Yuhong JIA Nan JI Haoyuan HUANG Yiya SUN Liguang 

机构地区：[1]Institute of Polar Environment, Department of Earth and Space Science, University of Science and Technology of China [2]National Synchrotron Radiation Laboratory, University of Science and Technology of China [3]Advanced Management Research Center, Ningbo University [4]State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences

出　　处：《Journal of Ocean University of China》2013年第4期605-610,共6页中国海洋大学学报（英文版）

基　　金：funded by the National Basic Research Program of China (973 Program,No.2010CB428902)

摘　　要：The biogenic silica (BSi) ,total organic carbon (TOC) ,total nitrogen (TN) and grain size were analyzed with a gravity core (3250-6) collected from the mud area in the north East China Sea.The average deposition rate of the upper core was about 0.078cm yr1based on the results of 210Pbex.The mean grain size increased with depth in general.The frequency distribution of grain size showed that two marked changes of deposition environment occurred at 30 cm and 50 cm depths (about 1550 AD and 1300 AD,respectively) .The variations of BSi and TOC indicated two distinct major periods of primary productivity over the past 800 years:a stage of low primary productivity corresponding to weak upwelling and low nutrient input below 30 cm depth (about 1200-1550 AD) ,and a stage of high primary productivity with strong currents and upwelling above 30 cm depth (about 1550-1950 AD) .The stage with high primary productive appeared to be due to the northward-expanded muddy area caused by strong Asian Winter Monsoon and enhanced Yellow Sea Warm Current in winter.In conclusion,the BSi and TOC in the muddy sediments,the symbols of marine primary productivity,can be then used to investigate the evolution history of currents and relative climate change in the offshore areas.The biogenic silica （BSi）, total organic carbon （TOC）, total nitrogen （TN） and grain size were analyzed with a gravity core （3250-6） collected from the mud area in the north East China Sea. The average deposition rate of the upper core was about 0.078 cmyr^-1 based on the results of ^210Pb_ex. The mean grain size increased with depth in general. The frequency distribution of grain size showed that two marked changes of deposition environment occurred at 30 cm and 50 cm depths （about 1550 AD and 1300 AD, respectively）. The variations of BSi and TOC indicated two distinct major periods of primary productivity over the past 800 years： a stage of low primary productivity corresponding to weak upwelling and low nutrient input below 30 cm depth （about 1200-1550AD） and a stage of high primary productivity with strong currents and upwelling above 30cm depth （about 1550-1950AD）. The stage with high primary productive appeared to be due to the northward-expanded muddy area caused by strong Asian Winter Monsoon and enhanced Yellow Sea Warm Current in winter. In conclusion, the BSi and TOC in the muddy sediments, the symbols of marine primary productivity, can be then used to investigate the evolution history of currents and relative climate change in the offshore areas.

关 键 词：primary productivity biogenic silica muddy area Asian Winter Monsoon Yellow Sea Warm Current 

分 类 号：P73[天文地球—海洋科学]