Abstract

The Southern Ocean is characterized by high levels of endemism of its fauna and flora that has generally been related to the progressive isolation of the continent during the Eocene. However, recent studies using genetic or geomorphologic approximations have demonstrated that the complex history of the Drake Passage could have repeatedly generated conditions where marine organisms could have cross the gap between South America and Antarctica during the last 40Mya. During this project we propose to realize a comparative phylogeographic study of macroalgae using various genera common to both the Antarctic and South American coasts. We aim to estimate the genetic divergence and potential timescale of isolation between sister-species pairs on both side of the Antarctic circumpolar current and compare the impact of the bottlenecks linked to reduction of seaweeds habitats during glacial periods in both regions in order to determine which factors have promoted isolation and endemism in the Southern Ocean macroalgae.