Biogeography of Antarctic Seaweeds Facing Climate Changes

Abstract

The seaweed biogeography and diversity in remote areas, such as Antarctica, should be reassessed considering the population shifts induced by global changes. This chapter addresses the hypothesis that ecological isolation can be disrupted and that biogeographical distribution of some species could be altered by thermohaline changes, which in turn would alter the dispersal patterns of macroalgae driven by severe meteorological and oceanographic events. Algal growth and distribution are limited by physical and biological processes, acting as sensitive bioindicators of changes or abrupt oscillations in the environmental regimes. In addition, Antarctica represents a natural laboratory highly susceptible to the climate changes, and the monitoring of their ecosystems may help to predict their potential effects beyond the Southern Ocean. Another fundamental issue is to understand the increase in species richness due to the cryptic and alien species, considering shifts in their biogeographic distribution. The large-scale patterns of some of these species reported for Antarctica may provide clues to reevaluate aspects of endemism, biological corridors, ecotone, and expansion of geographical distribution of algal assemblages facing climate changes, reinforcing the hypothesis that these isolated ecosystems will become gradually more connected.