Differential effects of high temperature on the respiration of juvenile caribbean corals
Bulletin of Marine Science
The response of scleractinian recruits to rising temperature will play an important role in determining how coral populations will be affected by global climate change, yet understanding these responses is made difficult by the lack of empirical data. In this study, the effects of elevated temperature (29.3 degrees C vs 27.3 degrees C) oil small colonies (mean diameters of 3-9 mm) of the Caribbean corals Porites spp., Agaricia spp. (Lamarck, 1801), Siderastrea siderea (Ellis and Solander, 1786), and Stephanocoenia intersepta (Lamarck, 1816) were tested by measuring the oxygen diffusion boundary layer (DBL) over the coenosarc in darkness at a constant flow speed of 0.8 cm s(-1). The results were used to estimate the aerobic respiration by means of Fick's first law. Temperature had no effect on the DBL thickness, but there were interactive effects of temperature and taxon on the oxygen concentration adjacent to the tissue and the respiration rates. Between 27.3 degrees C and 29.3 degrees C, the respiration of coenosarc tissue increased dramatically for S. intersepta (Q(10) = 105), but decreased for Porites spp. (Q(10) = 0.1), and remained unchanged for Agaricia spp. and S. siderea. These trends are inconsistent with a kinetic model of the effects of temperature on aerobic respiration, and it is hypothesized that they reflect the effects of behavior (e.g., tissue contraction or altered fluid transport among polyps) in mediating changes in the metabolic activity of the coenosarc.