Advertisement

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
Article

Abstract

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.

Keywords

Calcification Rate Skeletal Deformity Growth Ratio Horizontal Diameter Calcification Pattern 
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.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Literature cited

  1. Dafni, J.: Abnormal growth patterns in the sea-urchin Tripneustes cf. gratilla (L) under pollution (Echinodermata: Echinoidea). J. exp. mar. Biol. Ecol. 47, 259–279 (1980)CrossRefGoogle Scholar
  2. Dafni, J.: Aboral depressions in the tests of the sea-urchin Tripneustes cf. gratilla (L) in the Gulf of Eilat, Red Sea. J. exp. mar. Biol. Ecol. 67, 1–15 (1983)Google Scholar
  3. Dafni, J.: Skeletal growth and calcification in the short-spined sea-urchin (Tripneustes gratilla elatensis). Ph. D. dissertation, 117 pp. Hebrew University of Jerusalem. In Hebrew with an English summary 1984Google Scholar
  4. Dafni, J.: Effect of mechanical stress on the calcification pattern in regular echinoids skeletal plates, pp 233–236. In: Echinodermata: Proc. 5th int. Echinoderm Conf., Galway, Sept. 1984. Ed. by B. F. Keegan and B. D. S. O'Connor. Rotterdam: A. A. Balkema 1985Google Scholar
  5. Dafni, J.: A biomechanical model for the morphogenesis of regular echinoid tests. Paleobiology 12, 143–160 (1986)Google Scholar
  6. Dafni, J.: A biomechanical approach to the ontogeny and phylogeny of echinoids. In: Echinoderm phylogeny and evolutionary biology. Ed. by C. R. C. Paul and A. B. Smith. London: John Wiley (In press)Google Scholar
  7. Dafni, J. and J. Erez: Differential growth in Tripneustes gratilla (Echinoidea), pp 71–75. In: Echinoderms: Proc. 4th int. Echinoderm Conf., Tampa Bay, Sept. 1981. Ed. by J. M. Lawrence. Rotterdam: A. A. Balkema 1982Google Scholar
  8. Dafni, J. and J. Erez. Skeletal calcification patterns in the sea urchin Tripneustes gratilla elatensis I. Basic patterns. Mar. Biol. 95, 275–287 (1987)Google Scholar
  9. Harkness, R. D.: Mechanical properties of collagenous tissues, Vol. 2A, pp 247–310. In: Treatise on collagen. Ed. by B. S. Gould, New York: Academic Press 1968Google Scholar
  10. Moore, H. B.: Irregularities in the test of regular sea-urchins. Bull. mar. Sci. 24, 545–567 (1974)Google Scholar
  11. Moss, M. L. and M. M. Meehan: Growth of the echinoid test. Acta Anat. 69, 409–444 (1968)PubMedGoogle Scholar
  12. Raup, D. M.: Theoretical morphology of echinoid growth. J. Paleont. 42 (Suppl.), 50–63 (1968)Google Scholar
  13. Strathmann, R. R.: The role of spines in preventing structural damage to the echinoid test. Paleobiology 7, 400–406 (1981)Google Scholar
  14. Telford, M.: Domes, arches and urchins: the skeletal architecture of echinoids (Echinodermata). Zoomorphology 105, 114–124 (1985)CrossRefGoogle Scholar
  15. Thompson, D. W.: On growth and form, 793 pp. Cambridge: Cambridge University Press 1917Google Scholar
  16. Wilkie, I. C.: Variable tensility in echinoderm collagenous tissues: a review. Mar. Behav. Physiol. 11, 1–34 (1984)Google Scholar

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

Personalised recommendations