Fossil diatom studies in paleolimnology: Developments since the 1980s

化石硅藻由于其丰度高、壳体易于保存,对环境变化敏感、分布范围广等特点,已成为古湖沼学研究中的重要研究手段。80年代以来国际上湖泊硅藻研究在以下几方面得到迅速发展:(1)系统分类;(2)与环境因子的关系;(3)湖泊酸化、富营养化;(4)气候变化;(5)转换函数;(6)再沉积作用和溶解作用;(7)与色素对比分析等。我国湖泊化石硅藻研究起步较晚,80年代以来已积累了一些研究资料,近年来此项研究已开始受到重视和加强。;The role of fossil diatom study in paleollmnology is to analogize the ancient lakes9 reconstruct their lake envirmnental evolution histories and find out lake function and lake variation regularities based upon the distribution, ecology and environmental condition of living diatom flora in modern lakes, and upon some other organic and inorganic indicators and dating data as well.Diatom has become an important tool in paleolimnologicai studies due to its high abandance, well-preserved frustule, sensitivity to changing environments, wide distribution and uncomplicated identification.Initial researche,on paieoenvironments of lacustrine fossil diatoms began at the middle nineteenth century.The subject has being forged rapidly since the 1980s, including 7 major aspects as follows: (1) systematic classification of diatoms, (2) relationship between diatoms and environmental factors, (3) diatoms and lake acidification and eutrophication, (4) diatoms and climatic changes, (5) transfer function between diatoms and water chemistry, (6) influence of reworking and dissolution on diatom distribution, and (7) correlation of diatoms and sedimentary pigments.Fossil diatom studies began rather late in China.There accumulated some research data in the past twenty years, including mainly: (1)fossil diatoms in Tertiary diatomaceous earth deposits, (2) fossil diatoms in plateau lakes in Xizang (Tibet), and (3) Quaternary lacustrine fossil diatoms and environmental changes, guice the academic level is quite lower as compared with the modern international levels The Chinese paleontological and Quaternary geological fields have to strengthen the studies on lacustrine fossil diatoms and their environmental significance.