Comparative Phylogeography of Antarctic Seaweeds: Genetic Consequences of Historical Climatic Variations

• Main Authors: Guillemin, Marie-Laure, González-Wevar, Claudio, Cárdenas, Leyla, Dubrasquet, Hélène, Garrido, Ignacio, Montecinos, Alejandro, Ocaranza-Barrera, Paula, Flores Robles, Kamilla
• Other Authors: Biologie évolutive et écologie des algues = Evolutionary Biology and Ecology of Algae (EBEA), Pontificia Universidad Católica de Chile (UC)-Sorbonne Université (SU)-Universidad Austral de Chile-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff = Roscoff Marine Station (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Research Center Dynamics of High Latitude Marine Ecosystems (Fondap-IDEAL), Universidad Austral de Chile, Instituto de Ciencias ambientales y evolutivas, Université Laval Québec (ULaval), Laboratorio de Ecosistemas Marinos Antárticos y Subantárticos, Universidad de Magallanes, Iván Gómez, Pirjo Huovinen
• Format: Book Part
• Language: English
• Published: HAL CCSD 2020
• Subjects: Southern Ocean; glacial cycles; Quaternary; bottleneck; reduced genetic diversity; marine macroalgae; [SDV.EE.BIO]Life Sciences [q-bio]/Ecology; environment/Bioclimatology; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics; Antarctic; The Antarctic; Antarc*
• Online Access: https://hal.science/hal-04059708; https://hal.science/hal-04059708/document; https://hal.science/hal-04059708/file/Guillemin_2020_Springer.pdf; https://doi.org/10.1007/978-3-030-39448-6_6

International audience In the Southern Ocean, rapid climatic fluctuations during the Quaternary are thought to have induced range contractions and bottlenecks, which drastically impacted marine communities. For photosynthetic macroalgae that are restricted to very shallow waters, survival in deep-water refugia is not possible. Comparing pattern of distribution of genetic diversity using sequences of mitochondrial and chloroplast markers in distinct species of green, brown and red macroalgae, we sought to detect common responses to the effect of these glacial cycles. All the Antarctic macroalgae were all characterized by very low genetic diversity, absence of genetic structure and significant signatures of recent population expansion. The eight studied species seem to have barely survived glacial events in situ, in a unique refugium from which they recolonized their current distribution area. We propose that polynyas or areas showing long-term geothermal activity along Antarctic continental margins or peri-Antarctic islands could be good candidate as glacial refugium, but more variable genetic markers will be needed to precisely pinpointing its location. Common haplotypes, scattered over hundreds or even thousands of kilometres of coastline, point out to long-distance dispersal of fronds drifting on the strong oceanic currents in the region as main mechanism of postglacial