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Marine Ecology Progress Series

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MEPS 397:197-208 (2009)  -  DOI:

Skeletal reorganisation affects geochemical signals, exemplified in the stylasterid hydrocoral Errina dabneyi (Azores Archipelago)

Max Wisshak1,*, Matthias López Correa1, Helmut Zibrowius2, Joachim Jakobsen3, André Freiwald1

1GeoZentrum Nordbayern, Universität Erlangen-Nürnberg, Loewenichstr. 28, 91054 Erlangen, Germany
2Station Marine d'Endoume, Rue Batterie des Lions, 13007 Marseille, France
3Rebikoff-Niggeler Foundation, Rocha Vermelha, 9900-451 Horta, Faial, Azores, Portugal

ABSTRACT: The pure white fans of the stylasterid Errina dabneyi are a conspicuous feature on the upper bathyal slopes in Azorean waters and were documented and recovered alive with the aid of a submersible in the southern Faial Channel. Etched vacuum-epoxy-casts of the aragonite skeleton, studied by scanning electron microscopy, reveal the 3-dimensional internal architecture comprising coenosarc canal meshwork, dactylopores, gastropores and ampullae. Near the surface, the canals are narrow and interconnected in a regular 3-dimensional meshwork. Deeper inside the canals are less abundant, more irregular and wider. This pattern implies that the skeletal architecture is modified during growth, with more central canals being enlarged by dissolution, and other canals, gastropores and dactylopores in turn being filled with aragonite reprecipitates. The skeleton is primarily composed of irregular spherulitic aggregates and overprinting during growth is evident from ghost structures in the form of successive semi-spherulitic infill of former canals. Due to differential dissolution and reprecipitation, this internal rebuild process inevitably involves an alteration of initial geochemical signatures such as stable isotope ratios (δ18O and δ13C), trace element signals and the distribution of radiogenic isotopes of carbon and uranium. This has to be taken into account when applying radiometric dating techniques and when using stylasterids as a geochemical archive.

KEY WORDS: Hydrozoa · Stylasteridae · Microstructure · Biomineralisation · Coenosarc canals · Geochemical signals · Stable isotopes · Epoxy-casting technique

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Cite this article as:   Wisshak M, López Correa M, Zibrowius H, Jakobsen J, Freiwald A (2009) Skeletal reorganisation affects geochemical signals, exemplified in the stylasterid hydrocoral Errina dabneyi (Azores Archipelago). Mar Ecol Prog Ser 397:197-208.

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