Foraminiferal genotype adaptation and their potential to enhance palaeoceanographic proxies

有孔虫基因型适应及其增强古海洋学代理的潜力

• 批准号: NE/D009707/1
• 负责人: Kathryn Frances Darling
• 金额: $ 38.42万
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FD009707%2F1
• 关键词: Foraminiferal; genotype; adaptation; their; potential

Planktonic foraminifers (forams) are an important group of single-celled organisms that live in the marine plankton. Their hard shells of calcium carbonate, imprinted with a chemical record of the environment in which they grew, are preserved as microfossils in the sediments where they have accumulated over millions of years. Researchers use them to reconstruct ocean circulation and climate in the past by assuming that all shells of a morphospecies (species defined by shape) were constructed within the same environmental range. Using a unique DNA marker in living forams, I have been able to show that this is not true. Each morphospecies often has several distinct genetic types (genotypes) and many are adapted to different environments. Genotypes therefore build their shells in different environments from one another and scientists are unknowingly using a mixture of different types. This is an unforeseen problem for researches using chemical evidence from fossil shells to understand past climate changes in these regions . During my Advanced Fellowship, my principle task has been to assess genetic variation within important morphospecies and the different adaptations of newly identified genotypes. I have collected thousands of samples to date from the high Arctic to the Antarctic, targeting regions of special interest to scientists who investigate changes in the past climate. Forams can be carried over great distances in the ocean currents and although there seem to be few barriers to dispersal, individual genotypes do have different adaptations and do not live everywhere. Some are more adapted to the heat or cold, others to different amounts or types of food. I have discovered that the same morphospecies living in both polar regions became genetically split around two million years ago when the cold glacial period began. The Antarctic ones also diverged again later and one become adapted to live in the extreme environment of the sea-ice while others have found themselves left behind, isolated in a cold current following the last glacial period. All this knowledge tells us about how life splits up into different species in the ocean and I have alerted scientists to many of these new evolutionary discoveries in leading journals. For past climate reconstruction, pooling several genotypes together must impose error into researcher's calculations and climate models. My evidence on the genetic diversity and ecology of living forams in the cold regions of the high latitude oceans has highlighted and solved some of these problems. I have provided scientists with new ways of improving accuracy in fossil record interpretation by utilising the changing shapes of foram shells in these regions. It is now a high priority to investigate the wind driven upwelling regions of the tropical and subtropical waters which play an equally vital role in earth's climate system to determine the genotypic structure of these quite different ecosystems. I propose to sample these regions during three separate cruises in the Indian and Pacific Oceans to determine which genotypes live there and the specific water column conditions they live in. I will combine genotyping at different depths with high resolution chemical analyses of the different layers of their shell produced during their life cycle. An extensive investigation into genotype shell shape will be carried out to facilitate their identification in the fossil record. Improving the resolution of present day low latitude data on the relationship between shell geochemistry and the physical environment in which genotypes grow is vital for past climate modelling. This work will be done in collaboration with a strong team of experts who work on the reconstruction of past climate both in the UK and abroad. In addition, a new data base of all genotyped specimens and their location is being compiled which will be made available for use by the scientific community when complete.

浮游生物有孔虫（孔）是生活在海洋浮游生物中的一组重要的单细胞生物。他们的碳酸钙钙的硬壳印在其生长环境的化学记录中，被保存在微化石中的沉积物中，它们积累了数百万年的时间。研究人员过去使用它们来重建海洋循环和气候，假设形态疗法的所有壳（由形状定义的物种）都在相同的环境范围内构建。在活孔中使用独特的DNA标记，我能够证明这不是事实。每种形态疗法通常都有几种不同的遗传类型（基因型），许多形态类型（基因型）适用于不同的环境。因此，基因型在彼此之间的不同环境中建立壳，科学家在不知不觉中使用了不同类型的混合物。对于使用化石壳的化学证据来了解这些地区过去气候变化的化学证据，这是一个无法预料的问题。在我的高级奖学金中，我的主要任务是评估重要形态学的遗传变异和新鉴定的基因型的不同适应性。迄今为止，我已经收集了数千个样本，从高北极到南极，针对特殊利益的区域，以调查过去气候变化的科学家。孔可以在洋流的距离内延伸，尽管似乎很少有分散的障碍，但单个基因型确实具有不同的适应性，并且不居住在任何地方。有些更适合热或寒冷，有些则适合不同量或类型的食物。我发现，在冷冰川时期开始时，生活在两个极地地区的相同形态疗法在遗传上分裂了。南极较晚的南极也再次分歧，一个人变得适应了海冰的极端环境，而其他人则发现自己留下了，在上一个冰川时期之后的寒冷电流中被隔离。所有这些知识都告诉我们有关生命如何分为海洋中不同物种的知识，我已经提醒科学家在领先期刊中对许多新的进化发现。对于过去的气候重建，将几种基因型汇集在一起​​必须将错误施加到研究人员的计算和气候模型中。我关于高纬度海洋寒冷地区生物孔的遗传多样性和生态的证据突出了并解决了其中一些问题。我通过利用这些区域中的孔弹壳的形状不断变化的形状，为科学家提供了提高化石记录解释准确性的新方法。现在，研究热带和亚热带水域的风驱动的上升区域是一个很高的优先事项，这些地区在地球气候系统中起着同样至关重要的作用，以确定这些完全不同的生态系统的基因型结构。我建议在印度和太平洋的三个单独巡游中采样这些区域，以确定哪些基因型居住在那里以及它们所处的特定水柱条件。我将在不同深度的基因分型与对生命周期中壳产生的壳的不同层的高分辨率化学分析相结合。将对基因型壳形状进行广泛的研究，以促进其在化石记录中的识别。改善当今的分辨率低纬度数据对壳地球化学与基因型生长的物理环境之间关系的分辨率对于过去的气候建模至关重要。这项工作将与一个强大的专家团队合作完成，他们在英国和国外重建过去的气候。此外，所有基因分型标本及其位置的新数据库都将在完成后可以被科学界使用。

项目成果

Ecological partitioning and diversity in tropical planktonic foraminifera.

• DOI: 10.1186/1471-2148-12-54
• 发表时间: 2012-04-16
• 期刊: BMC evolutionary biology
• 影响因子: 3.4
• 作者: Seears HA;Darling KF;Wade CM
• 通讯作者: Wade CM

Methodology for Single-Cell Genetic Analysis of Planktonic Foraminifera for Studies of Protist Diversity and Evolution

• DOI: 10.3389/fmars.2016.00255
• 发表时间: 2016-12
• 期刊: Frontiers in Marine Science
• 影响因子: 3.7
• 作者: Agnes K. M. Weiner;R. Morard;M. Weinkauf;K. Darling;Aurore André;F. Quillévéré;Y. Ujiié;C. Douady;C. de Vargas;M. Kučera

PFR2: a curated database of planktonic foraminifera 18S ribosomal DNA as a resource for studies of plankton ecology, biogeography and evolution

• DOI: 10.1111/1755-0998.12410
• 发表时间: 2015-11-01
• 期刊: MOLECULAR ECOLOGY RESOURCES
• 影响因子: 7.7
• 作者: Morard, Raphael;Darling, Kate F.;de Vargas, Colomban
• 通讯作者: de Vargas, Colomban