Relationships between the morphologic rates of diatom evolution and north Pacific Miocene circulation

硅藻演化形态速率与北太平洋中新世环流的关系

基本信息

批准号：
03640660
负责人：
TANIMURA Yoshihiro
金额：
$ 1.41万
依托单位：
National Science Museum
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03640660/
关键词：
Miocene diatom morphologic rates of evolution 海洋循環

项目摘要

Several centric diatoms having plicate valve face have been reported from Pacific Neogene to Quaternary ranging in age from approximately 0 to 17 Ma ; Thalassiosira yabei group (=Thalassiosira brunii, T.flexosa, T.grunowii, T. mioplicata, T.moholensis, T.praeyabei, T.temperei, T.yabei, and others). These forms share a quite alike plication, one side convex and other side concave, of valve and intermediate forms occur fairly commonly among forms. Hence it appears that these plicated forms seem to be on the same evolutionary line.To provide information for the relationship between the morphologic rates of evolution of T.yabei group and mid Miocene high diatom production associates with Miocene North Pacific paleoclimatic and paleoceanographic changes, measurements of valve dimensions were made on 11 morphotypes, classified in this study, from Middle to Late Miocene part of their evolutionary line.The biometric evidence suggests that 1) the stock of this evolutionary line is T. praeyabei, 2) morphologic rates of evolution increases in Middle Miocene (15-13Ma), and 3) several descendants evolve from T.praeyabei at and around the interval. This increases in morphologic rates of evolution might have close relationship to auxospone formation which may be partly caused by intensified upwelling and high diatom production associated with mid Miocene cold events.This lineage also will define new biozones in a diatom zonal scheme for the Pacific Neogene, and a new genus, Plicatodiscus will be proposed in a following work.

据报道，从太平洋新近纪据报道了几个具有裂缝瓣面的硅藻面，年龄大约为0至17 mA。 Thalassira Yabei组（= Thalassiosira Brunii，T.Flexosa，T.Grunowii，T。Mioplicata，T.Moholensis，T.Praeyabei，T.Temperei，T.Temperei，T.Yabei等）。这些形式具有相当相似的折叠，一个侧凸和另一侧凹形，阀门和中间形式在形式之间通常出现。因此，看来这些镀膜形式似乎处于相同的进化线上。为了提供有关T. Yabei群体进化的形态学速率与中新世高硅藻生产的形态学率与中新世高硅藻的高硅藻生产伙伴关系，从而在11个自发上进行了11个自发性的研究，该研究的范围是在这种情况下进行的。生物识别证据表明1）该进化线的库存是t。praeyabei，2）中新世中期（15-13MA）的进化增长速率和3）几个后代从T.praeyabei在这间间隔内和周围进化。 This increases in morphologic rates of evolution might have close relationship to auxospone formation which may be partly caused by intensified upwelling and high diatom production associated with mid Miocene cold events.This lineage also will define new biozones in a diatom zonal scheme for the Pacific Neogene, and a new genus, Plicatodiscus will be proposed in a following work.