Advertisement

Hydromechanical Adaptations in AlcyoniumSidereum (Octocorallia)

  • Mark R. Patterson

Abstract

The relation between colony size and shape vs. flow regime was investigated in a boreal species of octocoral, Alcyonium sidereum with particular regard to two hydrodynamic problems faced by these organisms: (1) maximizing the area of feeding surfaces presented to flow while (2) limiting potentially damaging drag forces induced by water movement.

The results are summarized as follows: (1) A. sidereum exhibits three general morphologies depending upon flow regime: A) a stubby lobed morphology (CD = 0.37) is found in areas characterized by turbulent flow of high velocity (U > 25 cm/s), B) an ellipsoidal plate morphology (CD = 0.76) is found in areas of predictable bi-directional flow (10 < U < 25 cm/s), and C) an elongate pencil-like morphology (CD = 0.60), occasionally arborescent, is characteristic of calm areas (U < 10 cm/s). (2) Contraction of A. sidereum colonies during hydromechanical stress reduces their height above the substrate as well as their greatest horizontal dimension by 40–80%, significantly reducing drag. The normalized reduction is significantly greater in the height above the substrate indicating the importance of seeking the wall boundary layer during periods of strong flow. (3) Peak drag forces experienced by finger-like, lobed, and ellipsoidal colonies (isovolumetric) during storms were estimated to be 17 N, 9 N, and 23 N respectively. (4) Colony size (height above substrate) exhibits a positive correlation with water movement.

Keywords

Wind Tunnel Flow Regime Drag Force Colony Size Drag Reduction 
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. Abbott, B. M. 1974. Flume studies on the stability of model corals as an aid to quantitative paleoecology. Paleogeogr. Paleoclimatol. Paleoecolog., 15: 1–27.Google Scholar
  2. Barham, E. G., and I. E. Davies. 1968. Gorgonians and water motion studies in the Gulf of California. Underwat. Nat., 5: 24–28.Google Scholar
  3. Bidder, G. P. 1923. Relation of the form of a sponge to its currents. Quart. Journ. Micros. Sci., 67(2): 293–325.Google Scholar
  4. Chamberlain, J. A. and R. R. Graus. 1975a. Water flow and hydromechanical adaptations of branched reef corals. Bull. mar. Sci., 25: 112–125.Google Scholar
  5. Chamberlain, J. A. and R. R. Graus. 1975b. Adaptation in corals: How do corals withstand waves and currents? Abstracts with Programs, U.S. Geol. Soc. Ann. Meetings, Salt Lake City, Utah, p. 1024.Google Scholar
  6. Gosner, K. L. 1971. Guide to Identification of Marine and Estuarine Invertebrates. Wiley-Interscience, New York.Google Scholar
  7. Grigg, R. W. 1972. Orientation and growth form of sea fans. Limnol. Oceanogr., 17: 185–192.Google Scholar
  8. Jokiel, P. L. 1978. Effects of water motion on reef corals. J. exp. mar. Biol. Ecol., 35: 87–97.Google Scholar
  9. Kinzie, R. A., III. 1973. The zonation of West Indian gorgonians. Coral reef project-papers in memory of Dr. Thomas F. Goreau. Bull mar. Sci., 23: 93–155.Google Scholar
  10. Koehl, M.A.R. 1977a. Effects of sea anemones on the flow forces they encounter. J. exp. Biol., 69: 87–105.Google Scholar
  11. Koehl, M.A.R. 1977b. Water flow and the morphology of zoanthid colonies. Proc. Third Int. Coral Reef Symp., 1: 437444.Google Scholar
  12. LaBarbera, M. C. 1977. Brachiopod orientation to water movement 1: Theory, laboratory behavior and field observations. Paleobiol., 3(3): 270–287.Google Scholar
  13. Leversee, G. J. 1972. Field and laboratory studies of the effect of water currents on morphology and feeding in the seawhip, Leptogorgia. Am. Zool., 12: 719.Google Scholar
  14. Li, W.-H. and S-H. Lam. 1964. Principles of Fluid Mechanics. Addison Wesley, Reading, MA.Google Scholar
  15. Macurda, D. B. and D. L. Meyer. 1974. Feeding posture of modern stalked crinoids. Nature (Lond.), 247: 394–396.Google Scholar
  16. Meyer, D. L. 1973. Feeding behaviour and ecology of shallow-water unstalked crinoíds (Echinodermata) in the Carribean Sea. Mar. Biol., 22: 105–129.Google Scholar
  17. Muzik, K. 1978. A bioluminescent gorgonian, Lepidísis olapa, new species (Coelenterata, Octocorallia), from Hawaii. Bull. mar. Sci., 28(4): 735–741.Google Scholar
  18. Patterson, M. R. 1979. Hydromechanical investigations in the Cnidaría: investigations involving Alcyonium sidereum (Octocorallia) and Acropora palmata ( Scleractinia ). Unpublished MS.Google Scholar
  19. Pratt, E. M. 1905. The digestive organs of the Alcyonaria and their relation to the mesogleal cell plexus. Quart. Journ. Micros. Sci., 49: 327–362.Google Scholar
  20. Rees, J. T. 1972. The effect of current on the growth form in an octocoral. J. exp. mar. Biol. Ecol., 10: 115–124.Google Scholar
  21. Riedl, R. J. 1971. Water movement. In: Marine Ecology, Vol. I, Part 2. 0. Kinne, editor. Wiley Interscience, London, pp. 1085–1088, 1124–1156.Google Scholar
  22. Riedl, R. J. and R. Machan. 1972. Hydrodynamic patterns in lotic intertidal sands and their biological implications. Mar. Biol., 13: 179–209.Google Scholar
  23. Robins, M. W. 1968. The ecology of Alcyonium species in the Scilly Isles. Underwat. Ass. Rept., pp. 67–71.Google Scholar
  24. Roushdy, H. M. 1962. Expansion of Alcyonium digitatum (Octocorallia) and its significance for the uptake of food. Vidensk. Medd. bansk natur. Foren. Kjobenhaun, 124: 409–420.Google Scholar
  25. Roushdy, H. M. and V. K. Hansen. 1961. Filtration of phytoplankton by the octocoral Alcyonium digitatum L. Nature (London), 190: 649–650.Google Scholar
  26. Sverdrup, H. U., M. W. Johnson, and R. H. Fleming. 1942. The Oceans: Their Physics, Chemistry, and Biology. Prentice-Hall, New York.Google Scholar
  27. Svoboda, A. 1976. The orientation of Aglaophenia fans to current in laboratory conditions (Hydrozoa, Coelenterata). In: Coelenterate Ecology and Behavior. G. O. Mackie, editor. Plenum, New York, pp. 41–48.Google Scholar
  28. Théodor, J. 1963. Contribution à l’étude des Gorgones III. Trois formes adaptives d’Eunicella stricta en fonction de la turbulence et du courant. Vie et Milieu, 14: 815–818.Google Scholar
  29. Théodor, J. and M. Denizot. 1965. Contribution à l’étude des Gorgones. I. A porpos de l’orientation d’organismes marins fixés végétaux et animaux en fonction du courant. Vie et Milieu, 16: 237–241.Google Scholar
  30. Velimirov, B. 1976. Variation in forms of Eunicella cavolini Koch (Octocorallia) related to intensity of water movement. J. exp. mar. Biol. Ecol., 21: 109–117.Google Scholar
  31. Vogel, S. 1977. Current-induced flow through living sponges in nature. Proc. Nat. Acad. Sci., 74(5): 2069–2071.Google Scholar
  32. Vosburgh, F. 1977. The response to drag of the reef coral Acropora reticulata. Proc. Third Int. Coral Reef Symp., 1: 477–482.Google Scholar
  33. Wainwright, S. A. and J. Dillon. 1969. On the orientation of sea fans (genus Gorgonia). Biol. Bull., 136: 130139.Google Scholar
  34. Warner, G. F. 1971. On the ecology of a dense bed of the brittle-star Ophiothrix fragilis. J. mar. biol. Ass. U.K., 51: 267–282.Google Scholar
  35. Warner, G. F. and J. D. Woodley. 1975. Suspension-feeding in the brittle-star Ophiothrix fragilis. J. mar. biol. Ass. U.K., 55: 199–210.Google Scholar
  36. Zerbe, W. B. and C. B. Taylor, 1953. Sea water density reduction tables. In: Coast and Geodetic Survey Special Publication, no. 298, Wash., D.C., U.S. Dept. of Commerce, pp. 18–19.Google Scholar

Copyright information

© Springer Science+Business Media New York 1980

Authors and Affiliations

  • Mark R. Patterson
    • 1
  1. 1.Museum of Comparative Zoology Laboratories 105Harvard UniversityCambridgeUSA

Personalised recommendations