Report Card: Potential Tipping Points for life in the Southern Ocean

There is now clear scientific evidence that the increasing magnitude and rate of anthropogenic carbon dioxide (CO2) emissions are causing rapid and unprecedented changes to the global ocean. These will have potentially serious impacts during the 21st century on the sustainability and management of many marine and coastal ecosystems. Research has shown that the Southern Ocean, in particular, is encountering significant changes linked to climate change. The changes in pH, temperature, circulation and sea ice - along with potential for increased fishing pressure - are all likely to have far-reaching consequences for all species that currently inhabit the Southern Ocean. One of the fundamental questions for marine scientists studying the Southern Ocean is how climate change will alter the growth of key prey species including phytoplankton, zooplankton and krill. Phytoplankton are the base Baleen whale. iStock of the marine food web, and even seemingly small changes in sea-ice, ocean circulation, chemistry and temperature will affect which species live, thrive and die in the ocean. The biological outcomes from these changes will be determined by the environment, timing, rate and magnitude of change in each stressor, the order in which the changes occur, and the potential for consequences to be compounded when multiple stressors change concurrently. Hence, understanding the impacts of climate change on Southern Ocean life requires us to consider which key species will be more sensitive to change, if change will have benefical or detrimental effects on marine life, and how change will vary from region to region. These new scientific insights will have important implications for management of fish stocks and high conservation value species throughout the region.