Investigation of Evolutionary Processes in Planktonic Foraminifera Using Stable Isotopic Analysis

利用稳定同位素分析研究浮游有孔虫的进化过程

• 批准号: 9204857
• 负责人: James Kennett
• 金额: $ 10万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-07-15 至 1994-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9204857&HistoricalAwards=false
• 关键词: Investigation; Evolutionary; Processes; Planktonic; Foraminifera

This study is an investigation of processes of evolution in planktonic foraminifera using stable isotopic analysis. In the absence of obvious barriers to gene flow such as land masses (e.g. Isthmus of Panama) or major oceanographic boundaries (e.g. Polar Front and Tasman Front), how does evolution proceed in large pandemic populations in which gene flow is readily maintained over great distances? How do chronospecies gradually evolve within one biographic province? Most models predict that evolutionary change in the deep-dwelling planktonic foraminifera occurs through segregation within the water column during times of well developed depth stratification. In broader terms, the globorotalid morphology is believed to have evolved iteratively in association with adaptation to increasing water depths. However, almost no data have been have been generated to test such hypotheses. We will isotopically analyze morphometrically-defined Late Miocene to Recent species of the Globoratalia (Globoconella) clade in sedimentary sequences that form a meridional transect in the southwest Pacific. A time-series strategy will be employed focusing upon those stratigraphic intervals in which there is overlap in the ranges of ancestor and descendant species. Some of the questions we will address include: Do ancestor and descendant species exhibit consistent differences in isotopic values, suggesting vertical or seasonal segregation in the water column? Are there isotopic trends within this clade, suggesting progressive habitation of cooler or warmer waters, either vertically or seasonally? Are the isotopic trends associated with paleoceanographic changes? Are the isotopic trends associated with specific morphological characters? Do ancestor and descendant species living in different water masses, some within and some peripheral to the main biogeographic range of the clade, exhibit similar differences in isotopic values and similar paleoceanographic and morphological associations? How do the stable isotopic results from the Globorotalia (Globoconella) clade compare with those from another deep-dwelling planktonic foraminiferal clade that, in part, exhibits similar morphologic characteristics: - the Globorotalia (Truncorotalia) clade?

本研究是利用稳定同位素分析研究浮游有孔虫的进化过程。 在没有明显的基因流动障碍的情况下，例如陆地（例如巴拿马地峡）或主要海洋边界（例如极地锋和塔斯曼锋线），在大流行群体中，基因流很容易在很长的距离内维持，进化是如何进行的？ 时间种如何在一个传记省份内逐渐演化？ 大多数模型预测，深部浮游有孔虫的进化变化是通过深度分层发育良好期间水柱内的分离而发生的。 从更广泛的角度来看，球状生物的形态被认为是随着适应水深的增加而迭代进化的。 然而，几乎没有生成数据来检验这些假设。 我们将对形成西南太平洋经向横断面的沉积序列中形态测定定义的晚中新世至近代的 Globoratalia (Globoconella) 分支进行同位素分析。 将采用时间序列策略，重点关注祖先和后代物种范围重叠的地层间隔。 我们将解决的一些问题包括：祖先和后代物种的同位素值是否表现出一致的差异，表明水体中的垂直或季节性分离？ 这个进化枝内是否存在同位素趋势，表明垂直或季节性地逐渐居住在较冷或较温暖的水域？ 同位素趋势与古海洋变化有关吗？ 同位素趋势是否与特定形态特征相关？ 生活在不同水体中的祖先和后代物种是否表现出相似的同位素值差异以及相似的古海洋和形态关联？ Globorotalia (Globoconella) 分支的稳定同位素结果与另一个部分表现出相似形态特征的深栖浮游有孔虫分支的稳定同位素结果如何比较： - Globorotalia (Trunco​​rotalia) 分支？