Dinocyst microlaminations and freshwater“red tides”recorded in Lake Xiaolongwan,northeastern China
作者单位：Institute of Geology and GeophysicsChinese Academy of Sciences
会议名称：《中国科学院地质与地球物理研究所2008学术年会》
会议日期：2009年
学科分类：083002[工学-环境工程] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 07[理学] 08[工学] 09[农学] 0903[农学-农业资源与环境] 0713[理学-生态学]
基 金：supported by the Key Project,CAS(KZCX3-SW-145) the National Natural Science Foundation of China(Grant no. 40571148,40472092 and 40502018)
关 键 词：Dinocyst microlamination Sediment trap Dinocyst flux Radiometric dating Red tide history
摘 要：We reported a special type of lamination formed in the sediments of Lake Xiaolongwan, northeastern *** lamination consists of light-and brown-colored laminate couplets in the thin *** brown-colored layer is composed mainly of dinoflagellate *** grey-colored layer consists of other organic and siliceous matter(plant detritus,diatoms,chrysophyte cysts) and clastics. Preliminary sediment trap results show that a distinct peak of dinocyst flux occurred in *** dinocyst flux maximum also corresponds to the peaks of diatom flux and chrysophyte stomatocyst flux. These suggest that red tide blooms occur in this freshwater *** speculate that the dinocyst flux maximum could be related to autumn overturn due to increased nutrients,and the availability of cysts for germination from the lake ***,it may also reflect increasing dissolved organic matter after leaf *** independent chronology derived from Cs and Pb shows a good agreement with counted *** the sediment trap data and the independent chronology data,the dinocyst mi-crolaminae appear to be annually laminated,and probably could be called dinocyst *** vegetative(thecate stage) cells of Peridinium volzii and Ceratium furcoides are found in the water samples,it is not possible to relate the dinocysts to these two dinoflagellate *** on morphological and ecological analyses,we suggested that they have affinities with species of Peridinium(sensu lato),most probably to *** investigations should be carried out to understand the red tide history in this freshwater *** laminated dinocyst microlayers in freshwater and marine sediments not only provide an uncommon archive for understanding the history of red tides and harmful algal blooms,and why and how certain species periodically bloom over several thousands years,but also provide important records of paleo-environmental and paleoclimatic changes at seasonal to an