Marine Biology

, Volume 95, Issue 2, pp 289–297 | Cite as

Skeletal calcification patterns in the sea urchin Tripneustes gratilla elatensis (Echinoidea: Regularia)

II. Effect of various treatments
  • J. Dafni
  • J. Erez


Morphometrically determined growth measurements and 45Ca calcification assays were applied to deformed Tripneustes gratilla elatensis collected between 1979 and 1981 from polluted environments in the Gulf of Eilat, Israel, in order to check the effect of various pollutants and treatments on skeletal growth and structure. Deformed sea urchins showed low calcification rates and aberrant plate calcification gradients, as well as irregular sutural calcification patterns, characterized by very high vertical vs horizontal plate-edge growth ratios (v/h). This was consistent with their abnormal skeletal morphology, characterized by high height vs horizontal diameter (H/D) ratio. Similar growth and calcification patterns were shown by hard-substratum sea urchins transferred onto artificial sandy habitats. They became taller (having higher H/Ds), showing irregular sutural calcification patterns and higher v/h ratios. This phenomenon is apparently due to a biomechanical effect related to the weaker adherence of the ambulacral tubefeet suctorial discs. This experiment supports the hypothesis that the pollutants, industrial calcification inhibitors, are causing defomities in T. g. elatensis by affecting their calcification rate as well as their differential growth patterns. These results agree with a recently proposed biomechanical model suggesting that mechanical forces, internal liquid pressure and the activity of various contractile and elastic tissue elements control the growth and calcification of plates along their sutural edges, consequently determining the overall test morphology. It is suggested that the skeletal deformities, observed in earlier studies of this subspecies, resulted from an irreversible abnormal calcification pattern, which is often associated with changes in the proposed stress-balance.


Calcification Rate Skeletal Deformity Growth Ratio Horizontal Diameter Calcification Pattern 
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Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • J. Dafni
    • 1
  • J. Erez
    • 1
  1. 1.H. Steinitz Marine Biology LaboratoryThe Hebrew University of JerusalemEilatIsrael

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