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An Absence of Ocean Acidification and Warming Impacts on a Red Sea Coral

Paper Reviewed
Bellworthy, J., Menoud, M., Krueger, T., Meibim, A. and Fine, M. 2019. Developmental carryover effects of ocean warming and acidification in corals from a potential climate refugium, the Gulf of Aqaba. Journal of Experimental Biology 222: jeb186940, doi:10.1242/jeb.186940.

In a recent study on the combined effects of so-called ocean acidification and warming on corals, Bellworthy et al. (2019) exposed mature colonies of the reef-building coral Stylophora pistillata to extreme seawater conditions of pH 0.4 units lower and temperatures 5°C warmer than they are today. The experiment was timed to coincide during the corals' peak planulae brooding season such that the authors could evaluate the physiological effects of the treatment conditions on both adult and offspring larvae.

The work was conducted in a controlled environment at the Interuniversity Institute for Marine Sciences in Eilat, Israel. Adult S. pistillata corals were sourced from the Gulf of Aqaba in the northern Red Sea, acclimated to the experimental conditions, and then studied along with the planulae they released by means of multiple measurements over the course of a 33-day experimental period.

In discussing their findings, Bellworthy et al. report that "planulae from this population showed similar physiology irrespective of the environment, with a wide phenotypic range within a single cohort." Notably, they add that under the experimental conditions "S. pistillata planulae were resistant in terms of their settlement, physiology and survival, even when parents were exposed to severe ocean acidification and warming during the gamete maturation, fertilization and brooding period."

Based on the above findings, the authors thus conclude that S. pistillata corals display "inherent broad physiological resistance." And because that resistance was evident to even the most extreme predictions of future ocean acidification and warming (Representative Concentration Pathway 8.5), it would appear a solid bet that these corals will be around for centuries to come.

Posted 23 December 2019