现代藻类磷酸盐埋藏学实验——对磷酸盐化球状化石研究的启示  

Modern algal phosphate taphonomy experiments:Inspiration for the study of phosphated spheroidal fossils

作　　者：张神功 钟振华 陈雷 刘慧渊 杨锋杰 ZHANG Shengong;ZHONG Zhenhua;CHEN Lei;LIU Huiyuan;YANG Fengjie(School of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao,Shandong 266590,China)

机构地区：[1]山东科技大学地球科学与工程学院,山东青岛266590

出　　处：《地质学报》2023年第12期4035-4043,共9页Acta Geologica Sinica

基　　金：国家重点研发计划(编号2016YFC0601001,2017YFC0603100);山东省泰山学者青年专家计划专项(编号tsqn201812069);中国地质调查项目(编号DD20190009)联合资助的成果。

摘　　要：产于贵州瓮安埃迪卡拉系陡山沱组磷块岩中的“瓮安生物群”是认识早期生命起源与演化的重要窗口。因为其特殊的磷酸盐化作用,其中的球状化石内部保存了大量精细的细胞甚至亚细胞结构,但保存这些化石的磷酸盐化作用机理尚不清楚。因此,本文采用绿藻门下团藻和空球藻为实验对象,通过改变pH、温度、氧气含量等实验条件,探索藻类在不同埋藏环境下的保存状况,为早期磷酸盐化化石的埋藏机制提供证据。实验结果显示藻类在不同实验条件下的保存潜力差距较大,相同环境下两种藻类所体现的保存潜力也不一致,但都具备足够的保存潜力;空球藻细胞在埋藏过程中出现褶皱变形,但在不同条件下的形态学差异并不明显;团藻的繁殖体形态与瓮安生物群中的一类多细胞球状化石的细胞分裂形式十分相似;早期状态一致的同种藻类不管在相同还是不同的实验条件下其个体直径大小均表现出较强的差异性。本次实验模拟自然状态下的埋藏环境,因此实验现象可能在现实埋藏过程中重现,通过实验得出以下结论:磷酸盐化的埋藏环境中藻类具备足够的保存潜力;磷酸盐化会导致生物获得自身以外的形态学信息;在不同的埋藏学环境下保存的磷酸盐化球状化石的直径大小会有差异;胚胎状化石与磷酸盐化的现生藻类并不完全相同,它们之间的相似性可能来自于趋同演化,因此不能直接将它们等同看待。The Weng'an biota in the Ediacaran Doushantuo Formation phosphorus block in Weng'an,Guizhou is an important window to understand the origin and evolution of early life.Because of their special phosphosalination,globular fossils preserve a great deal of fine cellular and even subcellular structures.However,the mechanism by which these fossils are preserved is unclear.Therefore,in this paper,Volvox and Eudorina were used as experimental objects to explore the preservation status of algae under different burial environments by changing the pH,temperature and oxygen availability,to simulate the burial environment of early phosphate fossils.The results showed that there was a large difference in the conservation potential of algae under different experimental conditions.Though the conservation potential of the two species of algae under the same environment was not consistent,both had sufficient conservation potential.During the burial process,the cells of Chlorella were folded and deformed,but the morphological changes were not obvious under different conditions.The morphology of Volvox blooms is very similar to the cell division form of a kind of multicellular globular fossil in the Weng'an biota.Under the same or different experimental conditions,the individual diameter of the same species of algae with the same early state showed a strong difference.The experimental conditions were set to simulate the natural burial environment,so the experimental phenomenon may be reproduced in the real burial process.The experimental results show that the algae in the phosphate burial environment also have sufficient preservation potential.Phosphorylation can lead to the acquisition of morphological information outside the organism itself.We should be careful to classify the properties of phosphate globular fossils because the classification based on the diameter may not be reliable.Embryoid fossils are not directly equivalent to phosphatized algae,and their similarities may result from convergent evolution.

关 键 词：瓮安生物群 磷酸盐化 埋藏学实验 团藻 空球藻 

分 类 号：Q911.2[天文地球—古生物学与地层学]