Coral Reefs

, Volume 30, Issue 4, pp 925–933 | Cite as

Sclerite calcification and reef-building in the fleshy octocoral genus Sinularia (Octocorallia: Alcyonacea)

  • M.-S. JengEmail author
  • H.-D. Huang
  • C.-F. Dai
  • Y.-C. Hsiao
  • Y. Benayahu


Alcyonacean octocorals in tropical reefs are usually not considered as reef builders. Some Sinularia species, however, are capable of consolidating sclerites at the colony base to form spiculite. Nanwan Bay, southern Taiwan, features both fossilized and recently formed boulders composed of spiculite, thus demonstrating the role of Sinularia in contributing to the reef structure. Section radiography of an 18.5 kg spiculite boulder demonstrated a regular density banding of 3–6-mm intervals. Core survey indicated spiculite coverage of 25–30% on the live reef and of 30–40% on the uplifted boulders. Cores taken from living Sinularia revealed a distinct transition from discrete sclerites to compact spiculite and amorphous calcium carbonate cementing the sclerites. In the widespread S. gibberosa, sclerite formation appeared to start intracellularly, followed by a prolonged extracellular calcification process. At the calcification site, multiple sclerocytes formed expanded pseudopod-like membranes that interconnected, forming multicellular vesicles (MCVs) around the sclerites. The MCVs and the pseudopods disappeared at sclerite maturation, followed by degradation of the sclerocytes around the mature sclerites. At the colony base, granular vesicles were distributed among the sclerites, indicating a cementing process in progress. These findings suggest that colonies of Sinularia are able to cement sclerites and consolidate them at their base into spiculite, thus making them reef builders.


Reef-building Octocorals Spiculite Sinularia Calcification Sclerite cementation Taiwan 



The authors thank Mr. T.-S. Chen and the Administration of Kenting National Park, Taiwan for assistance with the fieldwork. Y. Benayahu was partly supported by the Israel Cohen Chair in Environmental Zoology. We also acknowledge the funding and electron microscope support from the Research Center for Biodiversity, Academia Sinica, Taiwan.


  1. Accordi G, Carbon F, Matteuci R (1989) ‘Alcyonaria spiculite’ nei calcari recifali quaternari della costa Somala. Rend Soc Geol Italia 12:17–20Google Scholar
  2. Alstyne LLV, Waylie CR, Paul VJ, Meyer K (1992) Antipredator defenses in tropical Pacific soft corals (Coelenterata: Alcyonacea). I. Sclerites as defenses against generalist carnivorous fishes. Biol Bull 182:231–240CrossRefGoogle Scholar
  3. Benayahu Y, Jeng M-S, Perkol-Finkel S, Dai C-F (2004) Soft corals (Octocorallia: Alcyonacea) from southern Taiwan. II. Species diversity and distributional patterns. Zool Stud 43:548–560Google Scholar
  4. Bengtson S (1981) Atractosella, a Silurian alcyonacean octocoral. J Paleontol 55:281–294Google Scholar
  5. Cary LR (1931) Studies on the coral reefs of Tutuila, American Samoa, with special reference to the Alcyonaria. Carnegie Inst Wash Publ 27:53–98Google Scholar
  6. Chen Y-G (1993) Sea-level change and neotectonics in southern part of Taiwan region since Late Pleistocene. Ph.D. dissertation, National Taiwan University, p 158Google Scholar
  7. Dai C-F (1991a) Distribution and adaptive strategies of alcyonacean corals in Nanwan Bay, Taiwan. Hydrobiologia 216(217):241–246CrossRefGoogle Scholar
  8. Dai C-F (1991b) Reef environment and coral fauna of southern Taiwan. Atoll Res Bull 354:1–24Google Scholar
  9. Fabricius K, Alderslade P (2001) Soft corals and sea fans: a comprehensive guide to the tropical shallow water genera of the central-west Pacific, the Indian Ocean and the Red Sea. Australia Institute of Marine Science, Townsville, p 264Google Scholar
  10. Goldberg WM, Benayahu Y (1987) Spicule formation in the gorgonian coral Pseudoplexaura flagellosa. 1. Demonstration of intracellular and extracellular growth and the effect of ruthenium red during decalcification. Bull Mar Sci 40:287–303Google Scholar
  11. Grillo MC, Goldberg WM, Allemand D (1993) Skeleton and sclerite formation in the precious red coral Corallium rubrum. Mar Biol 117:119–128CrossRefGoogle Scholar
  12. Isa Y (1986) An electron microscope study on the mineralization of the skeleton of the staghorn coral Acropora hebes. Mar Biol 93:91–101CrossRefGoogle Scholar
  13. Johnson DP, Risk MJ (1987) Fringing reef growth on a terrigenous mud foundation, Fantome Island, central Great Barrier Reef, Australia. Sedimentology 34:275–287CrossRefGoogle Scholar
  14. Johnston IS (1980) The ultrastructure of skeletogenesis in hermatypic corals. Int Rev Cytol 67:171–214CrossRefGoogle Scholar
  15. Kingsley RJ (1990) Calcium carbonate spicules in the invertebrates. In: Joseph GC (ed) Skeletal biomineralization: patterns, processes and evolutionary trends, vol I. Van Nostrand Reinhold, New York, pp 27–34Google Scholar
  16. Kingsley RJ, Dupree JL (1993) Seasonal localization of a collagenous protein in the organic matrix of sclerites from the gorgonian Leptogorgia virgulata (Cnudarua: Gorgonacea). Cell Tiss Res 273:309–316CrossRefGoogle Scholar
  17. Kingsley RJ, Watabe N (1982) Ultrastructure of the axial region in Leptogorgia virgulata (Cnidria: Gorgonacea). Cell Tiss Res 233:325–334CrossRefGoogle Scholar
  18. Kingsley RJ, Melaro EW, Flory KE, Skorupa AM, Harclerode KA (1996) Mechanisms of the annual cycling of organic-matrix collagen from spicules of the gorgonian Leptogorgia virgulata. Invert Biol 115:89–98CrossRefGoogle Scholar
  19. Kleypas JA (1996) Coral reef development under naturally turbid conditions: fringing reefs near Broad Sound, Australia. Coral Reefs 15:153–167Google Scholar
  20. Konishi K (1981) Alcyonarian spiculite: Limestone of soft corals. Proc 4th Int Coral Reef Symp 1:643–649Google Scholar
  21. Le Tissier MD (1991) The nature of the skeleton and skeletogenic tissues in the Cnidaria. Hydrobiologia 216(217):397–402CrossRefGoogle Scholar
  22. Lin M-C, Dai C-F (1997) Morphological and mechanical properties of two Alcyonaceans, Sinularia flexibilis and S. capillosa. Zool Stud 36:58–63Google Scholar
  23. Muscatine L, Tambutte E, Allemand D (1997) Morphology of coral desmocytes, cells that anchor the calicoblastic epithelium to the skeleton. Coral Reefs 16:205–213CrossRefGoogle Scholar
  24. Rahman MA, Omura T (2009) In vitro regulation of CaCO3 crystal growth by the highly acidic proteins of calcitic sclerites in soft coral, Sinularia polydactyla. Connect Tissue Res 50:285–293PubMedGoogle Scholar
  25. Schuhmacher H (1997) Soft corals as reef builders. Proc 8th Int Coral Reef Symp 1:499–502Google Scholar
  26. Tentori E, Van Ofwegen LP (2011) Patterns of distribution of calcite crystals in soft corals sclerites. J Morph. doi: 10.1002/jmor.10942
  27. Verseveldt J (1980) A revision of the genus Sinularia May (Octocorallia, Alcyonacea). Zool Verh Leiden 179:166Google Scholar

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • M.-S. Jeng
    • 1
    Email author
  • H.-D. Huang
    • 2
  • C.-F. Dai
    • 3
  • Y.-C. Hsiao
    • 1
  • Y. Benayahu
    • 4
  1. 1.Biodiversity Research CenterAcademia SinicaTaipeiTaiwan
  2. 2.National Museum of Natural ScienceTaichungTaiwan
  3. 3.Institute of OceanographyNational Taiwan UniversityTaipeiTaiwan
  4. 4.Department of ZoologyTel Aviv UniversityRamat Aviv, Tel AvivIsrael

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