Supplementary A: GBS Sample Data from Integrating kelp genomic analyses and geological data to reveal ancient earthquake impacts

Detached buoyant kelp can disperse thousands of kilometres at sea and can colonize newly available shores in the wake of disturbances that wipe out competitors. Localized earthquake uplift can cause extirpation of intertidal kelp populations followed by recolonization. Sources of recolonizing kelp can be detectable in genomic structure of contemporary populations. Our field observations combined with LiDAR mapping identified a previously unrecognized zone of uplifted rocky coastline in a region that is slowly subsiding. Intertidal kelp (<i>Durvillaea antarctica</i>) on the uplifted section of coast is genetically distinctive from nearby populations, with genomic signatures most similar to that of kelp 300 km to the south. Genetic divergence between these locations suggests reproductive isolation for thousands of years. Combined geological and genetic data suggest that this uplift event occurred during one of four major earthquakes between 6000 and 2000 years ago, with one of the younger events most likely. Extirpation of the pre-existing kelp required sudden uplift of approximately 2 metres, precluding several small incremental uplift events. Our results show the power of integrating biological (genomic) analyses with geological data to understand ancient geological processes and their ecological impacts.

脱离母体的漂浮型海带可在海洋中扩散数千公里，并能在清除竞争者的扰动事件后，于新近形成的岸域完成定植。局地地震抬升可引发潮间带海带（intertidal kelp）种群的局部灭绝，随后迎来种群的重新定植。重新定植的海带的来源，可通过当代种群的基因组结构进行溯源。我们的野外观测结合激光雷达（LiDAR）测绘，在一处正缓慢沉降的区域中，发现了此前未被识别的岩质海岸抬升带。该抬升海岸带的潮间带海带（南极牛海带，Durvillaea antarctica）与邻近种群存在显著遗传分化，其基因组特征与向南300公里处的海带种群最为相似。两地间的遗传分化表明，二者已维持数千年的生殖隔离。综合地质与遗传数据推断，此次抬升事件发生于距今6000至2000年间的四次强地震之一，其中较晚发生的那次可能性最高。原有海带种群的灭绝需要约2米的突发性抬升，这排除了多次小幅渐进式抬升事件的可能性。本研究结果证实了将生物学（基因组学）分析与地质数据相结合的研究方法，在解析古地质过程及其生态影响方面的重要价值。