This French harbor’s microorganisms have never fully recovered from the Second World War. Raffaele Siano collected sediment cores from the seafloor at Brest Harbor between 2012 and 2017, curious to see what he would discover. Upon analyzing the DNA fragments found in those cores, he and his colleagues at the French Institute for Ocean Science (Ifremer) made an astounding discovery.
The genetic remnants of plankton found in the shallower, more recent sediment levels were remarkably different from the dinoflagellate evidence found in the oldest, deepest sediment layers, which date back before 1941. “There was a group, an order of these dinoflagellates, that was very abundant before World War Two—and after World War Two it almost disappeared,” Siano explains.
