ANTARCTICA IS NOT ISOLATED AS WE THOUGHT
For years Antarctica has long been considered biologically isolated, however, this idea has been changing in the last time. Researchers discovered a giant kelp that has drifted 20,000 kilometres to reach an Antarctic beach, this is the longest known biological rafting event ever recorded.
DNA studies, and using the science of ocean drift that is used to track plastics, aeroplane crash debris and other floating material across our seas helped researchers to make up this kelp trip. DNA analysis found one kelp specimen drifted all the way from the Kerguelen Islands and another from South Georgia. Foreign floating kelp essentially surfed to Antarctica, with the help of wind-driven surface waves during storms.
- Locations of samples used in DNA analyses (white triangles), representing the entire range of the species. The orange and yellow lines show the average simulated dispersal routes for kelp released from Kerguelen and South Georgia, respectively, that reached Antarctica near King George Island show.
Global warming will make parts of Antarctica more habitable for invasive species, yet presumed barriers to dispersal—especially the Southern Ocean’s strong, circumpolar winds, ocean currents and fronts—have been thought to protect the region from non-human colonizations from the north. Researchers believe that storm and ocean eddies can dramatically enhance oceanographic connectivity for marine organism that float on the southern ocean surface to reach Antarctica, which is not biologically isolated at all.
Photo: Bull kelp is able to circumvent the Antarctic Polar Front and get to Antarctica, Credit: Ceridwen Fraser, ANU.
Reference: Fraser et al., 2018. Antarctica’s ecological isolation will be broken by storm-driven dispersal and warming. Nature Climate Change
[Image description: A penguin lies back to the sea. Between the penguin and the shore there is a stranded bull kelp, which is robust and flat.]
