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    Risk maps for Antarctic krill under projected Southern Ocean acidification

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    Document Number:
    S. Kawaguchi, A. Ishida, R. King, B. Raymond, N. Waller, A. Constable, S. Nicol, M. Wakit and A. Ishimatsu
    Submitted By:
    Mr Doug Cooper (CCAMLR Secretariat)
    Nature Climate Change, 3 (2013): 843–847, doi: 10.1038/NCLIMATE1937

    The embryonic development of Antarctic krill (Euphausia superba) is sensitive to elevated seawater CO2 levels and successful hatching is impaired at CO2 levels greater than 1000 μatm. Exposure to elevated CO2 during the first 3 days of embryonic development significantly retards subsequent development even if the embryos are transferred to seawater with current levels of CO2. Krill embryos appear more vulnerable to ocean acidification than other pelagic crustaceans such as copepods. pCO2 in the Southern Ocean are predicted by models to rise to above 1500 μatm in some parts of krill’s depth range by the year 2100 unless emissions are mitigated.  Risk maps, combining modelled hatch rates and the 3-dimensional circumpolar projection of future pCO2, predict that by 2100 the Weddell Sea and the waters to the east (the Haakon VII Sea) are the highest risk areas for krill embryos.  The entire Southern Ocean south of the Polar Front is predicted to be unsuitable for hatching by the year 2300, which would lead to collapse of the krill population. This is the first report that explores the circumpolar impacts of ocean acidification on krill.