Diatom-based dissolved inorganic nitrogen reconstruction in the Changjiang River estuary and its adjacent areas  

作　　者：Xin FAN Fangjin CHENG Zhiming YU Xiuxian SONG 

机构地区：[1]College of Naval Architecture and Port Engineering,Shandong Jiaotong University,Weihai 264209,China [2]CAS Key Laboratory of Marine Ecology and Environmental Sciences,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China [3]Laboratory of Marine Ecology and Environmental Science,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China [4]University of Chinese Academy of Sciences,Beijing 100049,China [5]Environmental Monitoring Center of Qingdao,Qingdao 266003,China

出　　处：《Journal of Oceanology and Limnology》2023年第4期1464-1480,共17页海洋湖沼学报（英文）

基　　金：Supported by the Taishan Scholars Climbing Program of Shandong Province of 2019,the National Natural Science Foundation of China(No.41806091);the National Natural Science Foundation of China(No.41506142);the PhD Start-up Fund of Shandong Jiaotong University(Nos.BS201902055,BS201902051)。

摘　　要：A five-component weighted average partial least squares(WA-PLS)calibration model was developed by analysing diatom assemblages in 34 surface sediment samples(collected in 2015)from the Changjiang River estuary(CRE)and its adjacent areas to infer dissolved inorganic nitrogen(DIN)concentrations.Eighteen additional sets of surface sediment diatoms and corresponding upper water DIN data(collected in 2012)were used to evaluate the accuracy of the model,and the relationship between observed and diatom-inferred DIN(DI-DIN)values(R2=0.85)illustrated the strong performance of the transfer function,indicating that precise reconstructions of former DIN are possible.The diatom-DIN transfer function was applied to the diatom record from a sediment core DH8-2(1962‒2012)collected in the Fujian-Zhejiang area south of the CRE.The reconstruction based on the DI-DIN model showed a significant DIN increase from 1962-2012,reflecting the influence of human activities on the very large increase in eutrophication.Three distinct periods can be seen from the changes in DIN and diatom taxa.In the 1962-1972 period,the DIN content was relatively low,with an average of 5.94μmol/L,and more than 80%of the diatom species identified were benthic taxa.In the 1972-2004 period,as the impact of human activities intensified,large nutrient inputs caused the DIN content to increase,with an average of 8.25μmol/L.The nutrient inputs also caused a significant change in the nutrient components and a distinct increase in small planktonic taxa.In the 2004-2012 period,the DIN content continued to rise,fluctuating at approximately 10μmol/L.A continuous increase in the frequency of planktonic taxa(up to 65.48%)indicated that eutrophication was further intensified,which was confirmed by the transformation from diatom-induced red tide to dinoflagellate-induced red tide during this period.

关 键 词：Changjiang River estuary dissolved inorganic nitrogen(DIN)reconstruction DIATOMS transfer function 

分 类 号：X52[环境科学与工程—环境工程]