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Photo-gyrotactic bioconvection

Published online by Cambridge University Press:  18 April 2011

C. R. WILLIAMS*
Affiliation:
Department of Mathematics, University of Glasgow, University Gardens, Glasgow G12 8QW, UK
M. A. BEES
Affiliation:
Department of Mathematics, University of Glasgow, University Gardens, Glasgow G12 8QW, UK
*
Email address for correspondence: chll1@bas.ac.uk

Abstract

Many microorganisms exhibit taxes, biased swimming motion relative to a directional stimulus. Aggregations of cells with densities dissimilar to the medium in which they swim can induce hydrodynamic instabilities and bioconvection patterns. Here, three novel and mechanistically distinct models of the interaction of the two dominant taxes in suspensions of swimming phototrophic algae are presented: phototaxis, swimming towards or away from light, and gyrotaxis, a balance between viscous and gravitational torques. The descriptions are accordant with, and extend, recent rational models of bioconvection. In particular, the first model is for photokinesis–gyrotaxis, the second varies the cells' centre-of-mass offset, and the third introduces a reactive phototactic torque associated with the propulsive flagellar apparatus. Equilibria and linear-stability analysis in a layer of finite depth are analysed in detail using analytical and numerical methods. Results indicate that the first two models, despite their different roots, remarkably are in agreement. Penetrative and oscillatory modes are found and explained. Dramatically different behaviour is obtained for the model with phototactic torques: instabilities arise even in the absence of fluid motion due to induced gradients of light intensity. Typically, the response of microorganisms to light is multifaceted and thus some combination of the three models is appropriate. Encouragingly, qualitative agreement is found with recent experimental measurements on the effects of illumination on dominant pattern wavelength in bioconvection experiments. The theory may be of some interest in the emergent field of bioreactor design.

Type
Papers
Copyright
Copyright © Cambridge University Press 2011

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References

REFERENCES

Bees, M. A. & Croze, O. A. 2010 Dispersion of biased swimming microorganisms in a fluid flowing through a tube. Proc. R. Soc. Lond. A, 466 (2119), 20572077.Google Scholar
Bees, M. A. & Hill, N. A. 1997 Wavelengths of bioconvection patterns. J. Exp. Biol. 200, 15151526.Google ScholarPubMed
Bees, M. A. & Hill, N. A. 1998 Linear bioconvection in a suspension of randomly swimming, gyrotactic micro-organisms. Phys. Fluids 10, 18641881.CrossRefGoogle Scholar
Bees, M. A., Hill, N. A. & Pedley, T. J. 1998 Analytical approximations for the orientation distribution of small dipolar particles in steady shear flows. J. Math. Biol. 36, 269298.CrossRefGoogle Scholar
Cash, J. R. & Moore, D. R. 1980 A high order method for the numerical solution of two-point boundary value problems. BIT 20, 4452.CrossRefGoogle Scholar
Childress, S., Levandowsky, M. & Spiegel, E. A. 1975 Pattern formation in a suspension of swimming microorganisms: equations and stability theory. J. Fluid Mech. 69, 591613.CrossRefGoogle Scholar
van Dyke, M. 1968 Perturbation Methods in Fluid Mechanics. Academic.Google Scholar
Ghorai, S. & Hill, N. A. 2005 Penetrative phototactic bioconvection. Phys. Fluids 17, 074101.CrossRefGoogle Scholar
Ghorai, S., Panda, M. K. & Hill, N. A. 2010 Bioconvection in a suspension of isotropically scattering phototactic algae. Phys. Fluids 22, 071901.CrossRefGoogle Scholar
Häder, D.-P. 1987 Polarotaxis, gravitaxis and vertical phototaxis in the green flagellate Euglena gracilis. Arch. Microbiol. 147, 7983.Google ScholarPubMed
Hegemann, P. & Bruck, B. 1989 Light-induced stop response in Chlamydomonas reinhardtii: occurrence and adaptation phenomena. Cell Motil. Cytoskel. 14, 501515.CrossRefGoogle Scholar
Hill, N. A. & Bees, M. A. 2002 Taylor dispersion of gyrotactic swimming micro-organisms in a linear flow. Phys. Fluids 14, 25982605.CrossRefGoogle Scholar
Hill, N. A. & Häder, D.-P. 1997 A biased random walk model for the trajectories of swimming micro-organisms. J. Theor. Biol. 186, 503526.CrossRefGoogle ScholarPubMed
Hill, N. A., Pedley, T. J. & Kessler, J. O. 1989 Growth of bioconvection patterns in a suspension of gyrotactic micro-organisms in a layer of finite depth. J. Fluid Mech. 208, 509543.CrossRefGoogle Scholar
Hinch, E. J. & Leal, L. G. 1972 Note on the rheology of a dilute suspension of dipolar spheres with weak Brownian couples. J. Fluid Mech. 56, 803813.CrossRefGoogle Scholar
Jones, M. S., Le Baron, L. & Pedley, T. J. 1994 Biflagellate gyrotaxis in a shear flow. J. Fluid Mech. 281, 137158.CrossRefGoogle Scholar
Kamke, E. 1967 Differentialgleichungen Losungsmethoden und Losungen, vol. 1. Akademische Verlagsgesellschaft Geest and Portig K.-G..Google Scholar
Kessler, J. O. 1985 Co-operative and concentrative phenomena of swimming micro-organisms. Contemp. Phys. 26 (2), 147166.CrossRefGoogle Scholar
Kessler, J. O. 1986 The external dynamics of swimming micro-organisms. Prog. Phycological Res. 4, 258305.Google Scholar
Kessler, J. O. 1989 Path and pattern – the mutual dynamics of swimming cells and their environment. Comments Theor. Biol. 212, 85108.Google Scholar
Kevorkian, J. & Cole, J. D. 1981 Perturbation Methods in Applied Mathematics. Springer.CrossRefGoogle Scholar
Leal, L. G. & Hinch, E. J. 1972 The rheology of a suspension of nearly spherical particles subject to Brownian rotations. J. Fluid Mech. 55 (4), 745765.CrossRefGoogle Scholar
Manela, A. & Frankel, I. 2003 Generalized Taylor dispersion in suspensions of gyrotactic swimming micro-organisms. J. Fluid Mech. 490, 99127.CrossRefGoogle Scholar
Matthews, P. C. 1988 A model for the onset of penetrative convection. J. Fluid Mech. 188, 571583.CrossRefGoogle Scholar
Pedley, T. J., Hill, N. A. & Kessler, J. O. 1988 The growth of bioconvection patterns in a uniform suspension of gyrotactic micro-organisms. J. Fluid Mech. 195, 223237.CrossRefGoogle Scholar
Pedley, T. J. & Kessler, J. O. 1987 The orientation of spheroidal microorganisms swimming in a flow field. Proc. R. Soc. Lond. B 231, 4770.Google Scholar
Pedley, T. J. & Kessler, J. O. 1990 A new continuum model for suspensions of gyrotactic micro-organisms. J. Fluid Mech. 212, 155182.CrossRefGoogle ScholarPubMed
Platt, J. R. 1961 ‘Bioconvection patterns’ in cultures of free-swimming organisms. Science 133, 17661767.CrossRefGoogle ScholarPubMed
Plesset, M. S. & Winet, H. 1974 Bioconvection patterns in swimming microorganism cultures as an example of Rayleigh–Taylor instability. Nature 248, 441443.CrossRefGoogle ScholarPubMed
Rüffer, U. & Nultsch, W. 1991 Flagellar photoresponses of Chlamydomonas cells held on micropipettes. II. Change in flagellar beat pattern. Cell Motil. Cytoskel. 18 (4), 269278.Google Scholar
Straughan, B. 1993 Mathematical Aspects of Penetrative Convection. Longman.Google Scholar
Veronis, G. 1963 Penetrative convection. J. Astrophys. 137, 641663.CrossRefGoogle Scholar
Vincent, R. V. & Hill, N. A. 1996 Bioconvection in a suspension of phototactic algae. J. Fluid Mech. 327, 343371.CrossRefGoogle Scholar
Vladimirov, V. A., Wu, M. S. C., Pedley, T. J., Denissenko, P. V. & Zakhidova, S. G. 2004 Measurement of cell velocity distributions in populations of motile algae. J. Exp. Biol. 207 (7), 12031216.CrossRefGoogle ScholarPubMed
Wager, H. 1911 On the effect of gravity upon the movements and aggregation of Euglena viridis, Ehrb., and other micro-organisms. Phil. Trans. R. Soc. Lond. B 201, 333390.Google Scholar
Whitehead, J. A. & Chen, M. M. 1970 Thermal instability and convection of a thin fluid layer bounded by a stably stratified region. J. Fluid Mech. 40 (3), 549576.CrossRefGoogle Scholar
Williams, C. R. & Bees, M. A. 2011 A tale of three taxes: photo-gyro-gravitactic bioconvection. J. Exp. Biol. (in press).CrossRefGoogle Scholar
Zhang, L., Happe, T. & Melis, A. 2002 Biochemical and morphological characterization of sulphur-deprived and H2-producing Chlamydomonas reinhardtii (green alga). Planta 214, 552561.CrossRefGoogle Scholar
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