The Depth Limits of Red Sea Stony Corals: An Ecophysiological Problem (A Deep Diving Survey by Submersible)

Abstract
Along the Sinai coast of the Red Sea a deep diving survey with the research submersible GEO investigated the depth distribution of stony corals. 47 hermatypic species were identified below 50 m; 9 species extended below 100 m. Their depth distributions are related to light penetration. Observed changes in hermatype growth forms with depth were investigated and interpreted as photo‐adaptations. 10 species of ahermatypic corals were found between 100–205 m. Ahermatype growth forms are adaptations to plankton feeding and do not change with depth.