Abstract
Rapid environmental change and a complex glacial history in the Western Antarctic Peninsula (WAP) have likely shaped the structure and persistence of Antarctic benthic species, yet connectivity remains poorly resolved for key habitat‑forming taxa. Understanding spatial genetic structure in these species is essential to predict their resilience and to inform conservation in this rapidly warming region. Here, we used genome‑wide SNPs to assess connectivity in the Antarctic soft coral Alcyonium antarcticum across multiple spatial scales along the WAP, sampling 90 individuals from three regions spanning the northern, central, and southern peninsula, with additional local and fine‑scale sampling within King George Island. Using DArTseq‑derived SNPs and a hierarchical sampling design, we analysed genetic diversity, population structure, and gene flow across large (hundreds of kilometers), local (kilometers), and fine (meters) spatial scales. At the large scale, three genetic clusters corresponding to Adelaide, Doumer, and King George islands indicated strong structure consistent with persistent historical and oceanographic barriers. At the local scale, significant differentiation, isolation by distance, and high self‑recruitment revealed weakly connected subpopulations, while at the fine scale the absence of clones indicated predominantly sexual reproduction with limited larval dispersal. Genetic diversity was lower than in temperate and tropical octocorals, consistent with glacial bottlenecks. Overall, A. antarcticum forms highly structured and weakly connected populations, highlighting the need to protect multiple demographically independent populations in the rapidly warming WAP.
Acknowledgements
We thank the Instituto Antártico Chileno (INACH) for logistical support during fieldwork conducted between 2018 and 2020. This work was supported by the National Commission for Scientific and Technological Research of Chile through the Fondo de Financiamiento de Centros de Investigación en Áreas Prioritarias (FONDAP) program, research center IDEAL: Dynamics of High Latitude Marine Ecosystems (grant No. 15150003), and by a Becas Chile scholarship (Grant No. 72190630) awarded to P.B. Additional funding was provided by FONDECYT Grant No. 1241069, 1230158 and ANID NCN2021-033. P.B. and P.A. also acknowledge support from Québec-Océan and the International Research Laboratory Takuvik.
Funding
This work was supported by the National Commission for Scientific and Technological Research of Chile through the Fondo de Financiamiento de Centros de Investigación en Áreas Prioritarias (FONDAP) program, research center IDEAL: Dynamics of High Latitude Marine Ecosystems (grant No. 15150003), and by a Becas Chile scholarship (Grant No. 72190630) awarded to P.B. Additional funding was provided by FONDECYT Grant No. 1241069, 1230258 and ANID NCN2021-033. P.B. and P.A. also acknowledge support from Québec-Océan and the International Research Laboratory Takuvik.
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Bruning, P., Cárdenas, L., Guillemin, ML. et al. Multiscale genetic connectivity, kinship, and demographic history of the Antarctic soft coral Alcyonium antarcticum in the Western Antarctic Peninsula.
Sci Rep (2026). https://doi.org/10.1038/s41598-026-47577-5
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DOI: https://doi.org/10.1038/s41598-026-47577-5
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