Evidence that high pCO2 affects coral recruits through perturbed protein metabolism.
Society of Integrative and Comparative Biology Annual Meeting
The recruitment of larvae to benthic surfaces is critical for scleractinian corals, for the outcome determines where adults will live for decades and the extent to which populations grow. In the coming century, rising pCO2 poses new challenges to coral recruits, and while there is evidence of negative effects, little is known of the proximal mechanisms involved. We have developed techniques to grow coral recruits under ecologically relevant conditions and test their response to environmental conditions in the first few days of benthic existence. Initial experiments using this technique reveal that recruitment in Seriatopora caliendrum involves a 70% increase in metabolic rate within 3 d of settling, and that 86 Pa pCO2 depresses metabolic rate 12% within 5 d of benthic existence. The reduction in respiration at high pCO2 suggests that metabolic depression may be used as a short−term response to hypercapnea. We indirectly explored the role of protein synthesis in mediating these changes by measuring the respiration of S. caliendrum recruits with and without the protein inhibitor emetine following 1−4 d at 45 (ambient) versus 77 Pa pCO2 at 25.3°C. Two days after settlement, respiration was affected by the interaction of emetine and pCO2, with respiration reduced 63% at 45 Pa pCO2, but 26% at 77 Pa pCO2; this interaction disappeared in 5−day old corals, in which respiration was reduced 28% by emetine. These results suggest that high pCO2 affects protein metabolism in coral recruits, potentially by impairing protein synthesis but incurring new costs through other pathways. Further investigations of the effects of high pCO2 on protein metabolism in corals may be productive.
Oxford University Press
San Francisco, CA