Foreign kelp surfed to Antarctica

A research team led by ANU has found the first proof that Antarctica is not isolated from the rest of the Earth, with the discovery that foreign kelp had drifted 20,000 kilometres before surfing to the continent's icy shores. Scientists had previously thought that Antarctic plants and animals were distinct from others around the world because they were isolated, but this new research indicates that these differences are almost entirely due to environmental extremes rather than isolation. The kelp's journey is the longest known biological rafting event ever recorded and has helped the team re-evaluate the science of ocean drift that is used to track plastics, aeroplane crash debris and other floating material across our seas. Lead researcher Dr Crid Fraser from the ANU Fenner School of Environment and Society said DNA analysis found one kelp specimen drifted all the way from the Kerguelen Islands and another from South Georgia. She said the foreign kelp essentially surfed to Antarctica, with the help of wind-driven surface waves during storms. "This is an unequivocal demonstration that marine species from the north can reach Antarctica," Dr Fraser said. "To get there, the kelp had to pass through barriers created by polar winds and currents that were, until now, thought to be impenetrable." Modelling shows how the kelp could have reached Antarctica, which overturns scientific understanding of drift dispersal in the Southern Ocean, Dr Fraser said.