Metabolic costs of larval settlement and metamorphosis in the coral Seriatopora caliendrum under ambient and elevated pCO₂

We tested the effects of pCO₂ on Seriatopora caliendrum recruits over the first 5.3d of post-settlement existence. In March 2011, 11-20 larvae were settled in glass vials (3.2mL) and incubated at 24.0°C and ~250μmolquantam^-2s^-1 while supplied with seawater (at 1.4mLs^-1) equilibrated with 51.6Pa pCO₂ (ambient) or 86.4Pa pCO₂. At 51.6Pa pCO₂, mean respiration 7h post-settlement was 0.056±0.007nmolO₂recruit^-1min^-1, but rose quickly to 0.095±0.007nmolO₂recruit^-1min^-1 at 3.3d post-settlement, and thereafter declined to 0.075±0.002nmolO₂recruit^-1min^-1 at 5.3d post-settlement (all±SE). Elevated pCO₂ depressed respiration of recruits by 19% after 3.3d and 12% overall (i.e., integrated over 5.3d), and while it had no effect on corallite area, elevated pCO₂ was associated with weaker adhesion to the glass settlement surface and lower protein biomass. The unique costs of settlement and metamorphosis for S. caliendrum over 5.3d are estimated to be 257mJrecruit^-1 at 51.6Pa pCO₂, which is less than the energy content of the larvae and recruits.