Bioconvective dynamics

Dependence on organism behaviour

A. Czirók, I. Jánosi, J. O. Kessler

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

Bioconvection occurs when a macroscopic nonuniformity of the concentration of microbial populations is generated and maintained by the directional swimming of the organisms. This study investigated the properties of the patterns near the onset of the instability and later during its evolution into a fully nonlinear convection regime. In suspensions of the bacteria Bacillus subtilis, which tend to swim upwards in a gradient of oxygen concentration that they create by consumption, we discovered that the dominant wavelength at the onset of the instability is determined primarily by the cell density and is influenced only weakly by the fluid depth. This observation contrasts strongly with previous observations on the gravitactic alga Chlamydomonas nivalis, in which the opposite dependence was found. Considerable differences were also found in the long-term evolution of the convection patterns. These results demonstrate the existence of readily distinguishable types of bioconvection systems, even at early stages of the instability. The observed differences are clearly and causally correlated with disparate reasons for upward swimming by these microorganisms, leading to different geometric distributions of the density of the suspension.

Original languageEnglish
Pages (from-to)3345-3354
Number of pages10
JournalJournal of Experimental Biology
Volume203
Issue number21
Publication statusPublished - 2000

Fingerprint

Convection
algae
Suspensions
Chlamydomonas
organisms
Bacillus subtilis
convection
wavelengths
Cell Count
Oxygen
Bacteria
microorganisms
oxygen
bacteria
microorganism
alga
Population
wavelength
bacterium
fluid

Keywords

  • Aerotaxis
  • Bacillus subtilis
  • Bioconvection
  • Characteristic wavelength
  • Chemotaxis
  • Chlamydomonas sp.
  • Hydrodynamic instability
  • Pattern formation

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Agricultural and Biological Sciences (miscellaneous)

Cite this

Bioconvective dynamics : Dependence on organism behaviour. / Czirók, A.; Jánosi, I.; Kessler, J. O.

In: Journal of Experimental Biology, Vol. 203, No. 21, 2000, p. 3345-3354.

Research output: Contribution to journalArticle

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