Gyrotactic Buoyant Convection and Spontaneous Pattern Formation in Algal Cell Cultures
Regular convection patters may form spontaneously in isothermal liquids which contain swimming microorganisms. The energy for this dissipative process is supplied by the swimmers. Individual cell trajectories are guided by gravity and vorticity so that cells accumulate toward regions of the liquid where the downstreaming velocity is a maximum. This concentrative mechanism, named “gyro-taxis”, has been proven by the demonstration that swimming cells focus at the axis of a downward cylindrical Poiseuille flow of the cell culture. Since the density of the cells exceeds that of the liquid in which they swim, gyrotaxis reinforces vorticity. This convection pattern producing system has been named “Gyrotactic Buoyant Convection (GBC). At sufficient average cell concentration, GBC can cause localised intermittent concentration pulses.
KeywordsConvection Pattern Isothermal Liquid Gravitational Torque Concentration Pulse Cell Swimming
Unable to display preview. Download preview PDF.
- 1.A.M. Roberts, Geotaxis in Motile Organisms, J. Exp. Biol. 53, 687 (1970).Google Scholar
- 1a.Also A.M. Roberts, Hydrodynamics of Protozoan Swimming, in Biochemistry and Physiology of Protozoa, Vol. 4, 2nd Ed., M. Levandowsky and S. Hutner, eds., Academic Press, New York, 1981, pp. 5–66.Google Scholar
- 2.A similar development is given in A.M. Roberts, the Biassed Random Walk and the Analysis of Microorganism Movement, in Swimming and Flying in Nature, Wu, Brokaw and Brennen, eds., Plenum, New York, 1975, pp. 377–393. A rudimentary version of the theory is given by Lord Rothschild, in Spermatozoan Motility, D.W. Bishop, ed., Am. Assoc. Adv. Sci., Washington, D.C., 1962, pp. 13–29.Google Scholar
- 3.“Rheotaxis”, described by Roberts , is one component of gyrotaxis.Google Scholar
- 6.A. Ben-Amotz and M. Avron, Glycerol, β-Carotene and Dry Algal Meal Production by Commercial Cultivation of Dunaliella, in Algae Biomass, G. Shelef and C.J. Soeder, eds., Elsevier/North Holland, Amsterdam, 1980.Google Scholar
- 7.J.O. Kessler, M.D. Hurley, and B. Kingsolver, A Novel Harvest Technology for Dunaliella Phycoculture, in The Future of Small Energy Resources, R.F. Meyer and J.C. Olson, eds., UNITAR, McGraw Hill, New York, 1983, pp. 513–516.Google Scholar
- 8.J.O. Kessler, Algal Cell Harvesting, U.S. Patent 4,324,067, 1982.Google Scholar