A radial distribution of calices in coral skeleton of Pocillopora verrucosa (Ellis and Solander, 1786) against ocean currents.

The correlation between the internal calice arrangement and compressive behavior of the skeleton of coral Pocillopora verrucosa has been characterized. The internal calices of this skeleton are arranged radially from a central axis in each branch. Such an arrangement of the calices results in a gradient distribution of the compressive properties; the middle part provides a higher strength, and the marginal part of the coral branch can undergo larger deformation to a certain extent. That is to say, the coral skeleton can offer a stronger internal support and a tougher external layer. Thus, the coral skeleton, as a natural porous and mineral material, can effectively undergo the ocean currents and provides a sturdy framework to protect the living polyps. [ABSTRACT FROM AUTHOR]