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Hydrodynamics of wave-swept organisms


Sensors for measuring flow and force, installed in the intertidal zone

Our lab group has worked for many years to understand the ways in which various characteristics of fluid flow impose forces on intertidal plants and animals, and the resultant consequences these forces have for organism survival.  We are especially interested in organism-flow interactions that lead to size-specific physical disturbance, since such processes have the potential to select for distinct ranges of body size.

Using second-by-second field measurements of water velocity and acceleration in surf-zone habitats, coupled with simultaneous measurements of force imposed on organisms a few centimeters away, we have shown that a long-held paradigm of marine biomechanics (that intertidal organisms are constrained in size by rapid water accelerations) is likely false.  Instead, changes in shape with size (“allometric” patterns of growth) play a stronger role than has often been realized.  Recent data also suggest that a previously disregarded mechanism of force imposition may have size-dependent properties that could contribute to limits on size in intertidal organisms.  We are now following up on this issue – stay tuned!


One of our intertidal field sites; the breaking waves depicted are approximately 3 m in height

Selected publications:

Gaylord, B., C.A. Blanchette, and M.W. Denny.  1994.  Mechanical consequences of size in wave-swept algae.  Ecological Monographs 64: 287-313.

Denny, M.W., and B. Gaylord.  1996.  Why the urchin lost its spines: Hydrodynamic forces and survivorship in three echinoids.  Journal of Experimental Biology 199: 717-729.

Denny, M., B. Gaylord, B. Helmuth, and T. Daniel.  1998.  The menace of momentum: Dynamic forces on flexible organisms.  Limnology and Oceanography 43: 955-968.  Gaylord, B.  1999.  Detailing agents of physical disturbance: Wave-induced velocities and accelerations on a rocky shore.  Journal of Experimental Marine Biology and Ecology 239: 85-124.

Gaylord, B.  2000.  Biological implications of surf-zone flow complexity.  Limnology and Oceanography 45: 174-188.

Gaylord, B., B.B. Hale, and M.W. Denny.  2001.  Consequences of transient fluid forces for compliant benthic organisms.  Journal of Experimental Biology 204: 1347-1360.

Denny, M., and B. Gaylord.  2002.  The mechanics of wave-swept algae.  Journal of Experimental Biology 205: 1355-1362.

Wolcott, B.D., and B. Gaylord.  2002.  Flow-induced energetic bounds to growth in an intertidal sea anemone.  Marine Ecology Progress Series 245: 101-109.

Gaylord, B.  2007.  Hydrodynamic forces.  Pages 277-283 in M.W. Denny and S.D. Gaines (eds), Encyclopedia of tidepools and rocky shores.  University of California Press, Berkeley.

Miller, L.P., and B. Gaylord.  2007.  Barriers to flow: The effects of experimental cage structures on water velocities in high-energy subtidal and intertidal environments.  Journal of Experimental Marine Biology and Ecology 344: 215-228.

Gaylord, B., M.W. Denny, and M.A.R. Koehl.  2008.  Flow forces on seaweeds: Field evidence for roles of wave impingement and organism inertia.  Biological Bulletin 215: 295-308.

Gaylord, B.  2008.  Hydrodynamic context for considering turbulence impacts on external fertilization.  Biological Bulletin 214: 315-318.

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