Microscopic organisms swimming in turbulent flow/Larval Settlement

When organisms locomote and interact in nature, they must navigate through complex habitats that vary on many spatial scales, and they are buffeted by turbulent wind or water currents that also vary on a range of spatial and temporal scales. We have been studying behavioral and biophysical mechanisms that locomoting animals use to make their way through such dynamic, variable natural habitats.

One of the research systems we have been using to address this question are microscopic marine animals swimming in turbulent, wavy water flow over spatially-complex communities of organisms growing on surfaces. Field measurements of water motion are used to design realistic turbulent flow in a laboratory wave-flume over different substrata, particle-image velocimetry is used to measure fine-scale, rapidly-varying water velocity vector fields, and planar laser-induced fluorescence is used to measure concentrations of chemical cues from the substratum. We use individual-based models of small animals swimming in this unsteady flow to determine how their trajectories are affected by their locomotion through the water, rotation by local shear, response to odors, and transport by ambient flow. We are finding that the shears, accelerations, and odor concentrations encountered by small swimmers fluctuate rapidly, with peaks much higher than mean values lasting fractions of a second. Although microscopic organisms swim slowly relative to ambient water flow, their locomotory behavior in response to the rapidly-fluctuating shears and odors they encounter can affect where they are transported by ambient water movement.

Selected references on this topic

  • Koehl, M. A. R., T. M. Powell, and G. Dairiki. (1993) Measuring the fate of patches in the water: Larval dispersal. pp. 50-60 In, J. Steele, T. M. Powell, and S. A. Levin [eds.], Patch Dynamics in Terrestrial, Marine, and Freshwater Ecosystems. Springer-Verlag, Berlin. (overview)
  • Koehl, M. A. R. and T. M. Powell (1994) Turbulent transport of larvae near wave-swept shores: Does water motion overwhelm larval sinking? pp. 261-274 In, H. Wilson, G. Shinn, and S. Stricker [eds.], Reproduction and Development of Marine Invertebrates. Johns Hopkins Univ. Press, Baltimore, MD.
  • Koehl, M. A. R. (1998) Physiological, ecological, and evolutionary consequences of the hydrodynamics of individaul organisms. OEUVRE, (published electronically)    link to article
  • Koehl, M. A. R. and M. G. Hadfield (2004) Soluble settlement cue in slowly-moving water within coral reefs induces larval adhesion to surfaces. J. Mar. Sys. 49: 75-88.
  • Hadfield, M. G. and Koehl, M. A. R. (2004) Rapid behavioral responses of an invertebrate larva to dissolved settlement cue. Biological Bulletin 207: 28-43.
  • Hadfield, M. G., A. Faucci, and M. A. R. Koehl. (2006) Measuring recruitment of minute larvae in a complex field environment: The corallivorous nudibranch Phestilla sibogae (Bergh). J. Exp. Mar. Biol. Ecol. 338: 57-72.
  • Koehl, M. A. R., Strother, J. A., M. A. Reidenbach, J. R. Koseff, and M. G. Hadfield. (2007) Individual-based model of larval transport to coral reefs in turbulent, wave-driven flow: Effects of behavioral responses to dissolved settlement cues. Mar. Ecol Prog. Ser. 335: 1-18.
  • Koehl, M. A. R. (2007) Hydrodynamics of larval settlement into fouling communities. Biofouling 23: 357-368.
  • Koehl, M. A. R. and M. A. Reidenbach (2008) Swimming by microscopic organisms in ambient water flow. Exp. Fluids. 43: 755-768.
  • Reidenbach, M. A., J R. Koseff, and M. A. R. Koehl (2009) Hydrodynamic forces on larvae affect their settlement on coral reefs in turbulent, wave-driven flow. Limnol. Oceanogr. 54: 318-330.
  • Koehl, M.A.R. and M. Hadfield, (2010) Hydrodynamics of larval settlement from a larva's point of view. Integr. Comp. Biol. 50: 539-551.
  • Koehl, M. A. R. (2010) How does morphology affect performance in variable environments? In: In search of the causes of evolution. From field observations to mechanisms. P.R. Grant and B. Grant [eds.] Princeton University Press, pp. 177-191.
  • Koehl M.A.R. and Reidenbach M.A. (2010) Swimming by microscopic organisms in ambient water flow. In: Animal Locomotion, G. Taylor, M. Triantafyllou, and C. Tropea [eds.], Springer-Verlag. pp. 117-130.
  • Sutherland, K. R., J.O. Dabiri, and M.A.R. Koehl (2011) Simultaneous field measurements of ostracod swimming behavior and background flow. Limnology and Oceanography: Fluids and Environments 1:135-146.
  • Koehl, M. A. R., J. P. Crimaldi, and D. E. Dombroski (2013) Wind chop and ship wakes determine hydrodynamic stresses on larvae settling on different microhabitats in fouling communities. Mar. Ecol. Prog. Ser. 479: 47-62.
  • Robinson, H.E., C. M. Finelli, and M. A. R. Koehl (2013) Interactions between benthic predators and zooplanktonic prey are affected by turbulent waves. Integrative Biology 53: 810-820.
  • Hadfield, M. G., B. T. Neved, S. L. Wilbur, and M. A. R. Koehl (2014) The biofilm cue for larval settlement in Hydroides elegans (Polychaeta): is contact necessary or not?. Marine Biology 161: 2577-2587.
  • Pepper, R. J. S. Jaffe, E. Variano, and M. A. R. Koehl (2015) Zooplankton in flowing water near benthic communities encounter rapidly fluctuating velocity gradients and accelerations. Marine Biology 162: 1939-1954.
  • Koehl, M. A. R. and Cooper, T. (2015) Swimming in an unsteady world. Integr. Comp. Biology 55: 683-697. doi:10.1093/icb/icv092
  • Pujara, N, M. A. R. Koehl, and E. A. Variano (2018) Rotations and accumulation of ellipsoidal microswimmers in isotropic turbulence. J. Fluid Mechanics 838: 356-368.

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