Ocean acidification does not impact shell growth or repair of the Antarctic

21 Marine calcifiers are amongst the most vulnerable organisms to ocean acidification 22 due to reduction in the availability of carbonate ions for skeletal/shell deposition. 23 However, there are limited long-term studies on the possible impacts of increased 24 pCO2 on these taxa. A 7 month CO2 perturbation experiment was performed on one 25 of the most calcium carbonate dependent species, the Antarctic brachiopod 26 Liothyrella uva, which inhabits the Southern Ocean where carbonate ion saturation 27 levels are amongst the lowest on Earth. The effects of the predicted environmental 28 conditions in 2050 and 2100 on the growth rate and ability to repair shell in L.uva 29 were tested with four treatments; a low temperature control (0°C, pH7.98), a pH 30 control (2°C, pH8.05), mid-century scenario (2°C, pH7.75) and end-century scenario 31 (2°C, pH7.54). Environmental change impacts on shell repair are rarely studied, but 32 here repair was not affected by either acidified conditions or temperature. Growth 33 rate was also not impacted by low pH. Elevated temperature did, however, increase 34 growth rates. The ability of L.uva to continue, and even increase shell production in 35 warmer and acidified seawater suggests that this species can acclimate to these 36 combined stressors and generate suitable conditions for shell growth at the site of 37