Collaborative Research: Have Transantarctic Dispersal Corridors Impacted Antarctic Marine Biodiversity?

南极洲是地球上变暖最快的地方之一，一些报告表明，南极洲的环境正在接近或可能超过冰架崩溃的临界点。南极洲周围冰层的消失正在极大地改变海洋动物，特别是底栖海洋无脊椎动物物种的栖息地。在过去研究的基础上，这项研究将深入了解气候变化如何影响物种分布和群落结构。地质数据表明，在冰的范围相对于现代水平大大减少的时期，海洋航道连接着南极洲两侧的罗斯海和威德尔海。然而，大多数关于目前海洋无脊椎动物分布模式起源的理论都没有考虑到这种跨大西洋的联系。这项研究将使用分子基因组工具来探测南极海洋无脊椎动物的DNA，并探讨可能塑造南大洋动物生物多样性目前模式的因素的替代假设。研究将为预测物种分布如何随着南极冰盖的继续恶化而变化提供信息，并提供关于生物如何调整其范围以应对环境变化的关键信息。这项工作包括几项具体的外联活动，包括在K-8教室的演讲，几个关于南极基因组学和实地工作的短格式视频，以及两个为期3天的生物信息学方法讲习班。本项目还将培训至少4名研究生、一名博士后和几名本科生。本研究的总体目标是了解影响南极底栖海洋无脊椎动物多样性模式的环境因素。来自沉积物岩心和模型的证据表明，在过去的几百万年里，冰架崩塌发生了多次。在这些时期，跨大西洋航道连接罗斯海和威德尔海。这项研究将评估跨大西洋水道的存在是否有助于解释罗斯海和威德尔海底栖海洋无脊椎动物群之间观察到的相似性，而不是目前的其他假设（例如，通过南极绕极流扩散，或从普通的冰川避难所扩张）。将针对七种南极底栖无脊椎动物分类群，使用单核苷酸多态性标记对基因组中数千个位点进行取样，以检验关于南大洋种群遗传结构起源的替代假设。此外，研究将测试目前的范式，即密切相关的，往往是神秘的，物种之间的分歧是冰川作用造成的人口瓶颈的结果。具体来说，SNP数据将被映射到我们的三个目标类群的基因组草图上，以评估遗传分歧的程度并寻找选择的迹象。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Antarctica is among the most rapidly warming places on the planet, and some reports suggest the Antarctic environment is approaching, or possibly beyond, the tipping point for ice shelf collapse. The loss of ice around Antarctica is dramatically changing habitat availability for marine fauna, particularly benthic marine invertebrate species. Building on past studies, this research will provide insights into how changing climate impacts species distribution and community structure. Geological data suggests that during periods when ice extent was much reduced relative to modern levels, marine seaways connected the Ross and Weddell Seas on either side of Antarctica. However, most theories about the origins of current marine invertebrate distribution patterns fail to consider this transantarctic connection. This research will use molecular genomic tools to probe the DNA of Antarctic marine invertebrates and explore alternative hypotheses about factors that may have shaped current patterns of animal biodiversity in the Southern Ocean. Research will inform predictions about how species distributions may change as Antarctic ice sheets continue to deteriorate and provide critical information on how organisms adjust their ranges in response to environmental change. This work includes several specific outreach activities including presentations in K-8 classrooms, several short-format videos on Antarctic genomics and field work, and two 3-day workshops on bioinformatics approaches. A minimum of 4 graduate students, a postdoc and several undergraduates will also be trained during this project.The overarching goal of this research is to understand environmental factors that have shaped patterns of present-day diversity in Antarctic benthic marine invertebrates. Evidence from sediment cores and modeling suggests ice shelf collapses have occurred multiple times in the last few million years. During these periods, transantarctic seaways connected the Ross and Weddell Seas. This research will assess whether the presence of transantarctic waterways helps explain observed similarities between the Ross and Weddell Seas benthic marine invertebrate fauna better than other current hypotheses (e.g., dispersal by the Antarctic Circumpolar Current, or expansion from common glacial refugia). Seven Antarctic benthic invertebrate taxa will be targeted to test alternative hypothesis about the origins of population genetic structure in the Southern Ocean using Single Nucleotide Polymorphism (SNP) markers that sample thousands of loci across the genome. Additionally, research will test the current paradigm that divergence between closely related, often cryptic, species is the result of population bottlenecks caused by glaciation. Specifically, SNP data will be mapped on to draft genomes of three of our target taxa to assess the degree of genetic divergence and look for signs of selection. Research findings may be applicable to other marine ecosystems around the planet.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.