MEPS 366:305-309 (2008)  -  DOI: https://doi.org/10.3354/meps07562

ABSTRACT: O₂ consumption of a single embryo/planula at each developmental stage was monitored in the reef-building coral Acropora intermedia using an optical O₂-sensing system with our original micro-chamber system (6.28 µl). The lowest rate of O₂ consumption was observed in unfertilized eggs. After fertilization, O₂ consumption increased and remained constant until the prawn chip blastula stage. However, O₂ consumption began to increase again during the bowl-shaped blastula stage, which involves the formation of 2 germ layers and corresponds to the beginning of gastrulation. The rate of O₂ consumption peaked during the teardrop-shaped planula stage. During this stage planulae are able to swim actively, especially in the vertical plane, so an increase in energy consumption during this stage is to be expected. O₂ consumption began to decrease gradually 5 d after spawning. At this stage, the larvae frequently touched the substrate with their concave aboral end, which features numerous spirocysts required for substrate attachment. When the planulae began to settle, 7 d after spawning, the rate of O₂ consumption dropped to that of unfertilized eggs, suggesting that the planulae slowly use stored energy for crawling/settlement behavior and/or post-settlement growth and survivorship.

KEY WORDS: Development · Dispersal · Energy · Larva · Lecithotrophic · Metabolism · Recruitment · Settlement-competency period