ibclogo XVI International Botanical Congess


Abstract Number: 2382
Session = 16.3.1


THE BERING STRAIT CONNECTION: DISPERSAL AND SPECIATION IN BOREAL SEAWEEDS


Sandra Lindstrom, University of British Columbia, Vancouver, Canada


Many boreal seaweeds have sibling species or conspecific populations in the North Pacific and North Atlantic Oceans. This pattern presumably arose from dispersal through the Arctic Ocean after opening of Bering Strait in Miocene or Pliocene and subsequent speciation as the Arctic froze and the Strait closed during glaciations. Molecular studies suggest different geographic origins of vicariant clades: some come from the Pacific whereas others are Atlantic in origin. Recent stratigraphic data show that Bering Strait opened well before closure of the Panama Isthmus 3.5 Myr. This earlier opening allowed dispersal of Atlantic stock into the Pacific since water flowed south through Bering Strait. After closure of the Isthmus, water flowed north from the Pacific into the Arctic and Atlantic. Patterns of speciation will be discussed in light of these two distinct invasions.


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