How does rising atmospheric CO2 affect marine organisms?

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Antarctic Brachiopod Shell Growth and Repair in OA Conditions

Paper Reviewed
Cross, E.L., Peck, L.S. and Harper, E.M. 2015. Ocean acidification does not impact shell growth or repair of the Antarctic brachiopod Liothyrella uva (Broderip, 1833). Journal of Experimental Marine Biology and Ecology 462: 29-35.

Working with Antarctic brachiopods -- marine animals that have hard shells on their upper and lower surfaces, as opposed to the left and right arrangement in bivalve molluscs -- Cross et al. (2015) conducted a 7-month CO2 perturbation experiment where the effects of projected environmental conditions in 2050 and 2100 on the growth rate and ability of the brachiopods to repair their shells were tested in four different treatments: a low temperature control (0°C, pH 7.98), a pH control (2°C, pH 8.05), a mid-century scenario (2°C, pH 7.75) and an end-century scenario (2°C, pH 7.54). And what did they find by doing so?

The three UK researchers report that shell repair rate "was not affected by either acidified conditions or temperature." In the case of shell growth rate, it too was not affected by OA; but it was actually increased by elevated temperature. And they thus conclude that Liothyrella uva brachiopods living in the Southern Ocean, which they say has the naturally lowest carbonate ion saturation levels of the planet's widespread seas, "can survive, repair shell damage and deposit new shell after 7 months of exposure to forecasted 2050 and 2100 pH conditions."

Posted 30 April 2015