Coral Reefs

, Volume 1, Issue 1, pp 45–51 | Cite as

Skeletal development in Acropora cervicornis: I. Patterns of calcium carbonate accretion in the axial corallite

  • E. H. Gladfeiter


Scanning electron microscopy and serial petrographic thin sections were used to investigate skeletal elongation and mineralization in the perforate coral, Acropora cervicornis. The axial corallite extends by the formation of randomly oriented fusiform crystals which are deposited on its distal edge. Aragonitic needle-like crystals grow in random directions from the surface of these fusiform crystals. Only those needle-like crystals growing toward the calicoblastic epithelium (i.e. crystals whose growth axis is perpendicular to the plane of the calicoblastic cell membrane) continue to elongate. Groups of these growing crystals join to form well-defined fasciculi which make up the primary skeletal elements comprising the septotheca. The resulting skeleton is highly porous with all surfaces covered by the continuous calicoblastic epithelium. This cell layer is separated by thin mesoglea from the flagellated gastrodermis which lines the highly ramified coelenteron. Porosity and permeability of the skeleton decrease with distance from the tip. Density correspondingly increases due to the addition of aragonite to the fasciculi whose boundaries become less distinct as channels fill with calcium carbonate.


Permeability Scan Electron Microscopy Porosity Cell Layer Calcium Carbonate 
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Copyright information

© Springer-Verlag 1982

Authors and Affiliations

  • E. H. Gladfeiter
    • 1
    • 2
  1. 1.Department of BiologyUniversity of CaliforniaLos AngelesUSA
  2. 2.West Indies LaboratorySt. Croix

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