Potential impacts of climate change on the marine life of Chilean Patagonia

With elevated C02 concentrations and rising temperatures due to climate change, species ranges may shift to suitable areas if the process is slow enough. The Patagonian Fjord Region however with its lacerated labyrinth of... [ view full abstract ]

With elevated C02 concentrations and rising temperatures due to climate change, species ranges may shift to suitable areas if the process is slow enough. The Patagonian Fjord Region however with its lacerated labyrinth of fjords, channels and islands includes two major, climate-independent latitudinal barriers for species migration. In addition, the entire region is characterized by the overlap of many different abiotic parameters and gradients on a local and regional scale creating highly complex interference patterns. These patterns are responsible for the exceptionally high diversity of Chilean Patagonia hosting unique and highly fragile ecosystems. When these local gradients are altered due to climate change, the possibilities of species shifting along gradients are very restricted and soon lead to local dead ends so that many species might not have the option to move to areas with suitable conditions for their survival. Ocean acidification will pose an additional stress to calcifying organisms, especially in Patagonian fjords with already low pH. Since the aragonite saturation horizon in these fjords is very shallow, the zone for suitable habitats for some calcifying organisms may disappear. For the last decade we could document a dramatic decline in species diversity in the Comau fjord, but without highly protected marine areas as a reference it is difficult to distinguish between natural fluctuations and direct and indirect anthropogenic impacts. MPAs are important as refugia for species in decline but shifting distribution patterns require reliable predictive models and/or precautionary approaches to ensure efficient MPA networks even in a changing climate.