Historical and Contemporary Drivers of Macroalgal Reproductive System Variation along the Western Antarctic Peninsula

南极西部半岛巨藻繁殖系统变化的历史和当代驱动因素

• 批准号: 2301026
• 负责人: Charles Amsler
• 金额: $ 38.8万
• 依托单位: University of Alabama at Birmingham
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-07-01 至 2027-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2301026&HistoricalAwards=false
• 关键词: Historical; Contemporary; Drivers; Macroalgal; Reproductive

General abstractMost organisms alternate between life stages that vary in the number and arrangement of their chromosomes, in the number of cells they possess, and in the environmental conditions in which they are best adapted to live. Much of what we understand about these alternations comes from organisms like animals and land plants in which one of the two stages dominates the life cycle with the other small and short-lived. However, across the tree of life there are countless examples of organisms in which both stages are of long duration, multicellular, or both. These life cycles challenge common ideas used to explain ecological and evolutionary patterns we see in nature. Macroalgae (seaweeds) display a wide range of life cycle types and consequently are excellent models to test and expand ideas about how life cycles evolve. Undersea forests of seaweeds with a variety of life cycle types dominate the shallow waters of the western Antarctic Peninsula where they are ecologically important and, for most of the species, at the southern end of their geographic range. Using existing samples from previous expeditions to Antarctica, the investigators are uniquely positioned to test and expand knowledge of life cycle evolution and how this intersects with reproductive mode variation. This project will also further the NSF goals of training new generations of scientists and of making scientific discoveries available to the public. The project will support a postdoctoral scholar as well as a faculty member new to US Antarctic research. The investigators will take advantage of an existing program to include high school or undergraduate students in the work which will also expand mentorship experience for the postdoc. All team members will contribute by writing for blogs produced by professional societies for the public. Technical abstractExisting macroalgal taxa samples from across a latitudinal gradient in the western Antarctic Peninsula will be used to explore patterns of genetic diversity from the center to the southern latitudinal limits of their range. Not only will genetic diversity be documented for an understudied and critical group of Antarctic organisms, but how it changes with latitude, compounded by high levels of endemism, will be explored. This will be accomplished by (i) characterization of latitudinal gradients in genetic diversity of many species and (ii) determination of the reproductive system of five focal foundation species. At present, there are few genetic data for macroalgae, dominant primary producers in coastal ecosystems around the world. This gap is particularly acute along Antarctic coastlines that are experiencing rapid climate change. Furthermore, Antarctica is isolated by the Southern Ocean, decreasing the likelihood of regular migration from other land masses. Latitudinal reproductive system patterns are predicted to be largely driven by recolonization events that increase with latitude due to changes in iceberg scour and sea ice coverage. Thus, Antarctica is the best place to understand what processes underlie reproductive mode variation in populations that are isolated, including many endemic taxa, while simultaneously extending our knowledge about how marginal environments converge with complex life cycles.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

一般摘要大多数生物体在生命阶段之间交替，这些阶段的染色体数量和排列、它们拥有的细胞数量以及它们最适合生存的环境条件各不相同。我们对这些交替的了解大部分来自动物和陆地植物等生物体，其中两个阶段之一主导生命周期，而另一个阶段较小且寿命较短。然而，在生命之树上，有无数的生物体的例子，其中两个阶段都是长期持续的、多细胞的或两者兼而有之。这些生命周期挑战了用于解释我们在自然界中看到的生态和进化模式的常见观念。大型藻类（海藻）显示出广泛的生命周期类型，因此是测试和扩展有关生命周期如何演变的想法的绝佳模型。具有多种生命周期类型的海藻海底森林主导着南极半岛西部的浅水区，它们对生态具有重要意义，而且对于大多数物种来说，它们位于其地理范围的南端。利用之前南极洲探险的现有样本，研究人员具有独特的优势来测试和扩展生命周期进化的知识以及生命周期进化如何与生殖模式变异相交叉。该项目还将进一步推进 NSF 培养新一代科学家和向公众提供科学发现的目标。该项目将支持一名博士后学者以及一名刚接触美国南极研究的教员。研究人员将利用现有的计划，让高中生或本科生参与到这项工作中，这也将扩大博士后的指导经验。所有团队成员都将通过为专业协会为公众制作的博客撰写文章来做出贡献。 技术摘要来自南极半岛西部纬度梯度的现有大型藻类样本将用于探索从其范围的中心到南部纬度范围的遗传多样性模式。不仅将记录未被研究和关键的南极生物群体的遗传多样性，还将探索其如何随纬度变化以及高水平的特有现象。这将通过（i）许多物种遗传多样性的纬度梯度特征和（ii）确定五个焦点基础物种的生殖系统来完成。目前，大型藻类是世界各地沿海生态系统中的主要初级生产者，其遗传数据很少。这种差距在正在经历快速气候变化的南极海岸线尤其严重。此外，南极洲被南大洋隔离，降低了从其他陆地定期迁徙的可能性。预计纬度生殖系统模式很大程度上是由再殖民事件驱动的，由于冰山冲刷和海冰覆盖的变化，再殖民事件随着纬度的增加而增加。因此，南极洲是了解孤立种群（包括许多特有类群）生殖模式变异背后的过程的最佳地点，同时扩展我们关于边缘环境如何与复杂生命周期融合的知识。该奖项反映了 NSF 的法定使命，并已被通过使用基金会的智力优点和更广泛的影响审查标准进行评估，认为值得支持。