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、增殖和灭绝。大多数海洋物种缺乏物理屏障和庞大的种群规模，应该允许在物种形成后迅速扩散和定居新栖息地。然而，基因流动似乎比我们根据这一分析所预测的更为有限：许多浮游有孔虫物种在海洋盆地之间和海洋盆地内的首次出现日期具有跨时性，这表明种群的建立往往在物种形成后立即受到暂时的限制。最近的研究表明，即使在一个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所说的更强，（ii）对这些障碍的特性及其工作机制了解甚少。该研究将利用2019年5月至7月国际海洋发现计划（IODP）第383次探险期间回收的深海沉积物中的上新世-更新世浮游有孔虫，研究环南极开阔海域扩散动力学的环境驱动因素。被命名的研究人员Anieke Brombacher博士作为浮游有孔虫生物地层学家参加了383号考察队，是英国海洋发展计划资助的科学家。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越空间和时间的种群动态。利用IODP 383考察队回收的沉积物，我们将研究亚极地南太平洋的物种扩散和迁移，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探险队在南极前沿以北的南太平洋地区钻探了六个地点，这些地点非常适合制作高分辨率的沉积物记录，而不受大型浮冰的干扰。我们将在其中三个地点记录有孔虫的进化，并将这些记录与南极环极流（ACC）变化的地球化学重建进行比较。具体来说，从IODP站点U1539、U1540和U1541恢复的上新世-更新世高分辨率沉积物档案将用于研究边缘种群在连接太平洋和大西洋的高纬度海洋门户德雷克通道（Drake Passage）上的扩散，这是对40 kyr冰川旋回的响应。新近纪浮游有孔虫种Truncorotalia truncatulinoides、Globoconella puncticulata puncticuloides和Globoconella inflata均起源于西南太平洋。尽管Drake通道形成了一个明显的潜在迁徙路线，但在其他洋盆中尚未发现斑点斑蝶，而在热带至中纬度太平洋首次出现后，直到0.5-1.0 Myr， truncatulinoides和inflata才出现在大西洋。这一观察结果表明，高纬度地区在温带水物种的进化史早期为其扩散提供了环境障碍。来自IODP 383站点U1539 - U1541的初步船上结果显示，这些站点都位于西南太平洋南纬55度左右，在冰期-间冰期旋回中，组合成分各不相同。冰期组合以极地物种Neogloboquadrina pachyderma为主，而间冰期组合包含更多的温带物种，包括各种Truncorotalia和Globoconella分类群。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，这是一种类似于“岛屿希望”的机制。为了验证这一假说，需要高分辨率的物种计数、形态计量学和稳定的同位素数据来确定在连续的间冰期中，适应是否会随着暴露在海洋条件下而改善。

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