The impacts of past climate change on sub-Antarctic nearshore ecosystems

Abstract

Pleistocene glacial–interglacial cycles would have resulted in drastic changes in the structure of sub-Antarctic littoral ecosystems. Genetic data indicate that the large kelps that dominate intertidal and shallow subtidal sub-Antarctic shores today (such as Macrocystis pyrifera and Durvillaea antarctica) were extirpated from these high latitude regions by sea ice scour during glacial maxima. These macroalgae, and their associated faunal communities, were able to return to the sub-Antarctic islands during interglacial periods by drifting at sea in the path of the Antarctic Circumpolar Current. During glacial maxima, sub-Antarctic littoral communities would have been severely reduced, comprising mainly ice-scour hardy taxa such as small and/or seasonal macroalgae, and mobile molluscs.