Understanding of diachroneity: Palaeoenvironmental controls on dispersal of planktic foraminifera in the Plio-Pleistocene oceans

对历时性的理解：古环境对上里奥-更新世海洋中浮游有孔虫扩散的控制

• 批准号: NE/T012382/1
• 负责人: Paul Wilson
• 金额: $ 6.43万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FT012382%2F1
• 关键词: Understanding; diachroneity; Palaeoenvironmental; controls; dispersal

Macroevolution is the generation, proliferation and removal of species. The lack of physical barriers and large population size of most marine species should allow for rapid dispersal and colonization of new habitats following speciation. However, gene flow appears more limited than we would predict based on this analysis: diachronous first occurrence dates among and within ocean basins of many species of planktonic foraminifera suggest that population establishment is often temporarily restricted immediately after speciation. Recent work shows that even in a cosmopolitan marine diatom species, gene flow is restricted at an ocean basin scale. These observations indicate that (i) physical barriers to dispersion in the open ocean are stronger than commonly invoked and (ii) the identity of these barriers and their working mechanisms are poorly understood. The proposed research will study environmental drivers of dispersal dynamics in the open ocean of the circum- Antarctic using planktonic foraminifera of Plio-Pleistocene age in deep sea sediments recovered during International Ocean Discovery Program (IODP) Expedition 383 in May-July 2019. The named researcher, Dr Anieke Brombacher, participated in Expedition 383 shipboard as a planktonic foraminifer biostratigrapher as a UK-IODP sponsored scientist.Planktonic foraminifera are ideally suited for in-depth analysis of temporal dispersal dynamics because their high-resolution fossil record in marine sediments allows for reconstructions of population dynamics across space and through time. Using sediments recovered by IODP Expedition 383, we will study species dispersal and migration in the sub-polar Southern Pacific Ocean, a region that, via the Drake Passage, connects the Pacific and Atlantic Oceans but lies at the edge of many species' geographical ranges. Expedition 383 drilled six South Pacific sites well north of the Antarctic front, that are well-suited to producing extremely high-resolution sediment records undisturbed by major ice rafting. We will document foraminifera evolution at three of these sites and compare those records to geochemical reconstructions of variability in the Antarctic Circumpolar Current (ACC). Specifically, high-resolution Pliocene-Pleistocene sediment archives recovered from IODP Sites U1539, U1540 and U1541 will be used to study edge population dispersal through Drake Passage, a key high latitude ocean gateway connecting the Pacific and Atlantic Oceans in response to 40-kyr glacial cycles.The Neogene planktonic foraminifera species Truncorotalia truncatulinoides, Globoconella puncticulata puncticuloides and Globoconella inflata all originated in the Southwest Pacific Ocean. However, G. puncticulata puncticuloides has not been recorded in any other ocean basin, and T. truncatulinoides and G. inflata do not appear in the Atlantic Ocean until 0.5-1.0 Myr after their first appearance in the tropical to mid-latitude Pacific despite the Drake Passage forming an obvious potential migration route. This observation suggests that the high latitudes presented an environmental barrier to the dispersal of temperate-water species early in their evolutionary history. Initial shipboard results from IODP 383 Sites U1539 - U1541, all located around 55 degrees S in the SW Pacific, show varying assemblage compositions across glacial-interglacial cycles. Glacial assemblages are dominated by the polar species Neogloboquadrina pachyderma but interglacial assemblages contain more temperate species including various Truncorotalia and Globoconella taxa. These initial findings suggest that interglacials potentially act to weaken barriers to dispersal to higher latitudes and facilitate adaptation there, a mechanism akin to 'island hoping'. To test this working hypothesis, high-resolution species counts, morphometric and stable isotope data are required to determine whether adaptation improves with exposure to ocean conditions in successive interglacials.

宏观进化是物种的产生、增殖和消除。大多数海洋物种缺乏物理屏障且种群规模庞大，因此在物种形成后能够快速扩散并在新的栖息地中定居。然而，基因流似乎比我们根据此分析预测的更有限：许多浮游有孔虫物种在海洋盆地之间和之内的历时首次出现日期表明，种群建立通常在物种形成后立即受到暂时限制。最近的研究表明，即使在世界性的海洋硅藻物种中，基因流动也受到海洋盆地尺度的限制。这些观察结果表明，（i）公海中扩散的物理障碍比通常提到的更强大，并且（ii）这些障碍的身份及其工作机制人们知之甚少。拟议的研究将利用 2019 年 5 月至 7 月国际海洋发现计划 (IODP) 第 383 次远征期间回收的深海沉积物中的 Plio-更新世时代的浮游有孔虫，研究环南极公海扩散动态的环境驱动因素。研究员 Anieke Brombacher 博士作为浮游有孔虫生物地层学家参加了 Expedition 383 船上的活动作为英国 IODP 赞助的科学家。浮游有孔虫非常适合深入分析时间扩散动力学，因为它们在海洋沉积物中的高分辨率化石记录允许重建跨空间和跨时间的种群动态。利用 IODP 383 号探险队回收的沉积物，我们将研究副极地南太平洋的物种扩散和迁徙，该地区通过德雷克海峡连接太平洋和大西洋，但位于许多物种地理范围的边缘。 383 号探险队在南极锋以北的六个南太平洋地点进行了钻探，这些地点非常适合生成不受大型冰漂流干扰的极高分辨率沉积物记录。我们将记录其中三个地点的有孔虫进化，并将这些记录与南极绕极流（ACC）变化的地球化学重建进行比较。具体而言，从 IODP 站点 U1539、U1540 和 U1541 回收的高分辨率上新世-更新世沉积物档案将用于研究通过德雷克海峡的边缘种群扩散，德雷克海峡是连接太平洋和大西洋的关键高纬度海洋门户，以响应 40 公里的冰川新近纪浮游有孔虫物种 Trunco​​rotalia truncatulinoides, Globoconella puncticulata puncticuloides 和 Globoconella infata 均起源于西南太平洋。然而，G. puncticulata puncticuloides 尚未在任何其他洋盆中记录到，而 T. truncatulinoides 和 G. infata 直到首次出现在热带至中纬度太平洋后 0.5-1.0 Myr 才出现在大西洋，尽管德雷克海峡形成了一条明显的潜在迁徙路线。这一观察结果表明，高纬度地区对温带水生物种在进化历史早期的扩散构成了环境障碍。 IODP 383 个站点 U1539 - U1541 的初步船上结果均位于西南太平洋南纬 55 度左右，显示了冰期-间冰期旋回中不同的组合组成。冰川组合以极地物种 Neogloboquadrina pachyderma 为主，但间冰期组合包含更多温带物种，包括各种 Trunco​​rotalia 和 Globoconella 类群。这些初步发现表明，间冰期可能会削弱向高纬度地区扩散的障碍，并促进那里的适应，这种机制类似于“岛屿希望”。为了检验这一假设，需要高分辨率物种计数、形态测量和稳定同位素数据来确定适应是否会随着连续间冰期暴露于海洋条件而得到改善。

项目成果

Morphological variation across space does not predict phenotypic change through time in two Neogene planktonic foraminifera species

空间形态变化并不能预测两种新近纪浮游有孔虫物种随时间的表型变化

• DOI: 10.3389/fevo.2023.1165174
• 发表时间: 2023
• 期刊: Frontiers in Ecology and Evolution
• 影响因子: 3
• 作者: Brombacher A

A new sea-level record for the Neogene/Quaternary boundary reveals transition to a more stable East Antarctic Ice Sheet

新近纪/第四纪边界的新海平面记录揭示了向更稳定的东南南极冰盖的过渡

• DOI: 10.1073/pnas.2004209117
• 发表时间: 2020
• 期刊: Proceedings of the National Academy of Sciences
• 作者: Wilson;Fiebig;Repschläger;Friedrich
• 通讯作者: Friedrich