Corals Forced to Live in a CO2-Enriched and Warmer Environment
Schoepf, V., Grottoli, A.G., Warner, M.E., Cai, W-J., Melman, T.F., Hoadley, K.D., Pettay, D.T., Hu, X., Li, Q., Xu, H., Wang, Y., Matsui, Y. and Baumann, J.H. 2013. Coral energy reserves and calcification in a high-CO2 world at two temperatures. PLOS ONE 8: e75049.
According to the thirteen researchers, coral energy reserves were largely not metabolized "in order to sustain calcification under elevated pCO2 and temperature," in harmony with the fact that "maintenance of energy reserves has been shown to be associated with higher resistance to coral bleaching and to promote recovery from bleaching (Rodrigues and Grottoli, 2007; Anthony et al., 2009)." In fact, they say that lipid concentrations actually increased under ocean acidification conditions in both A. millepora and P. damicornis, and that they "were fully maintained in M. monasteriata and T. reniformis," while protein, carbohydrate and tissue biomass were also "overall maintained under ocean acidification conditions in all species." And, therefore, they found that "only one of the four corals species studied [Acropora millepora] decreased calcification in response to average ocean acidification levels expected by the second half of this century (741 ppm), even when combined with elevated temperature (+2.5°C)."
As a result of their several findings, Schoepf et al. conclude that "some corals could be more resistant to combined ocean acidification and warming expected by the end of this century than previously thought," such that "the immediate effects of rising seawater temperature and ocean acidification may be tolerable for some species," possibly because the increased availability of CO2(aq) under ocean acidification conditions may enhance algal productivity, especially in Symbiodinium phylotypes with less efficient carbon-concentrating mechanisms that rely to a greater extent on the passive, diffusive uptake of CO2(aq) and its fertilization effect, citing in this regard the work of Herfort et al. (2008) and Brading et al. (2011).
Anthony, K.R.N., Hoogenboom, M.O., Maynard, J.F., Grottoli, A.G. and Middlebrook, R. 2009. Energetics approach to predicting mortality risk from environmental stress: a case study of coral bleaching. Functional Ecology 23: 539-550.
Brading, P., Warner, M.E., Davey, P., Smith, D.J., Achterberg, E.P. and Suggett D.J. 2011. Differential effects of ocean acidification on growth and photosynthesis among ,phylotypes of Symbiodinium (Dinophyceae). Limnology and Oceanography 56: 927-938.
Herfort, L., Thake, B. and Taubner, I. 2008. Bicarbonate stimulation of calcification and photosynthesis in two hermatypic corals. Journal of Phycology 44: 91-98.
Rodrigues, I.J. and Grottoli, A.G. 2007. Energy reserves and metabolism as indicators of coral recovery from bleaching. Limnology and Oceanography 52: 1874-1882.