As Antarctica's temperature increases, the continent´s biological isolation begins to break.
Human impacts threaten not only species but also entire ecosystems. Ecosystems under stress can collapse or transition into different states, potentially reducing biodiversity at different scales. In recent decades, the Polar Regions’ sensibility to climate change has provided ample evidence of these changes. Both poles have been studied extensively, and though the Arctic has managed to hold the spotlight for years, relatively recent phenomena in Antarctica have shifted the scientific community's attention towards it.
Rising temperatures threaten Antarctica’s high levels of endemism
Due to both climate change and the Antarctic ozone hole, parts of Antarctica are now among the most rapidly warming regions on Earth. The changes in Antarctic sea ice dynamics currently observed along the coasts stem from this issue, and the consequences of this phenomena have managed to raise doubt around the continent´s long-thought biological isolation (a situation previously kept stable by temperature limitations, ocean fronts and currents, circumpolar winds, and whirlpools).
Back in 2015, when the IUCN Red List of Ecosystems published its first ecosystem risk assessment about the region “Vulnerability of Antarctic shallow invertebrate-dominated ecosystems”, it was predicted that earlier breakout of seasonal sea ice along the Antarctic coast would sharply increase annual light reaching some areas of the seabed. The impact could directly affect biota living on, within and below sea ice by removing habitat and driving regime shifts towards macroalgae-dominated communities. Three years later, with Antarctic sea-ice loss earlier in the season still taking place, and endemic species dying off even in stable coastline (i.e. Antarctic moss) due to the increasing temperatures, studies show the continent’s shores are quickly becoming hospitable to diverse sub-antarctic taxa.
Antarctica’s ecosystems face a transition period
Reproductively viable, sub-Antarctic kelp rafts (southern bull kelp Durvillaea antarctica) recently collected from Antarctic beaches exemplify one of many potential vectors for biological colonization of Antarctica. Their presence there could facilitate incursions of entire coastal benthic communities, thus having major and possibly permanent ecological effects within the environment. Given that biological dispersal to Antarctica via rafting is frequent, and that the extreme environmental conditions that previously prevented colonization attempts by sub-Antarctic taxa are slowly changing (i.e.winds), Antarctica’s ecosystems may well be amidst a transition period towards macroalgae-dominated ecosystems.
Research indicates that some parts of the marine shelf in Antarctica—especially along the West Antarctic Peninsula — could, by the end of this century, experience warming that would greatly reduce the survival of many Antarctic marine endemic species and facilitate survival of sub-Antarctic taxa.
Written by: Clara Gómez
Style and format: Lila García and Clara Gómez
Provita Oct 05, 2018