How does rising atmospheric CO2 affect marine organisms?

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Acidification Effects on Rock-Boring Sea Urchins of the Red Sea

Paper Reviewed
Hazan, Y., Wangensteen, O.S. and Fine, M. 2014. Tough as a rock-boring urchin: adult Echinometra sp. EE from the Red Sea show high resistance to ocean acidification over long-term exposures. Marine Biology 161: 2532-2545.

In an experiment designed to gain a better understanding of the effects of long-term exposure of adult Echinometra sp. EE sea urchins native to the Red Sea's Gulf of Aqaba, Hazan et al. (2014) studied specimens they collected there within eleven 37.5-liter glass aquariums they maintained in equilibrium with air containing either 435 or 1,433 µatm of CO2 - corresponding respectively to seawater pH values of 8.1 and 7.7 - for a period of eleven months, while they periodically examined them for somatic and gonadal growth and skeletal microstructure, during which time all urchins in the experiment completed full reproductive cycles typical of natural populations.

This work revealed that in the cases of (1) somatic and (2) gonadal growth, there were no significant differences between the sea urchins maintained in the two CO2 treatments. They also state that there was "no detectable impact of increased pCO2 on the [3] timing, [4] duration or [5] progression of the cycle." And they add that "scanning electron microscopy imaging of urchin tests and spines revealed no signs of the usual observed effects of acidosis, such as [6] skeletal dissolution, [7] widened stereo pores or [8] non-smoothed structures."

Taken together, these several findings, in the words of the four researchers, "suggest high resistance of adult Echinometra sp. EE to near future ocean acidification conditions." And we could well speculate much the same about far future ocean acidification conditions, which may not be as extreme as many climate alarmists suggest they could be.

Posted 23 February 2015