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Marine Biology

, Volume 129, Issue 4, pp 615–623 | Cite as

X-ray diffraction study of calcification processes in embryos and larvae of the brooding oyster Ostrea edulis

  • D. Medaković
  • S. Popović
  • B. Gržeta
  • M. Plazonić
  • M. Hrs-Brenko
Article

Abstract

X-ray powder diffraction was used to study shell calcifications of the oyster Ostrea edulis, sampled in the Limski Kanal, Istria (Adriatic Sea), in May 1992. All the developmental stages were followed, from the embryonic stage through the transition between the trochophore and veliger larva (prodissoconch I and II) and later, after swarming, the pelagic free-swimming larval stages, up to their settlement and attachment (from the D-shaped to the fully formed pediveliger larva), and finally during metamorphosis and juvenile stages (dissoconch). In the first gastrula stage, only an amorphous tissue is present (a periostracum and organic matrix). The beginning of shell formation (at the end of gastrulation) in early trochophores is manifested by the appearance of calcite (up to 1–7% of total volume) and then aragonite (about 1%). In the later stage of the veliger larva the fraction of calcite decreases as well as the amorphous fraction, while the fraction of aragonite rapidly increases. In the prodissoconch II stage and during the whole pelagic period aragonite is dominant, accompanied by a very small amorphous fraction and traces of calcite. The shell mineral composition does not change until metamorphosis, whereupon the fraction of calcite rapidly increases and the fraction of aragonite decreases. The postmetamorphic valves of the juvenile and adult oyster consist mainly of calcite, except the resilium and myostracum which remain aragonitic, possibly as a continuation of the inner layer of the larval shell.

Keywords

Calcite Mineral Composition Juvenile Stage Embryonic Stage Shell Formation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • D. Medaković
    • 1
  • S. Popović
    • 2
  • B. Gržeta
    • 2
  • M. Plazonić
    • 2
  • M. Hrs-Brenko
    • 1
  1. 1.Ruđđer Bošković Institute, Center for Marine Research Rovinj, 52210 Rovinj, Croatia
  2. 2.Ruđer Bošković Institute, Materials Science and Electronics Department, P.O. Box 1016, 10001 Zagreb, Croatia

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