Evaporation-driven convective flows in suspensions of non-motile bacteria
| Autor: | Jocelyn Dunstan, Kyoung J. Lee, Simon F. Park, Yongyun Hwang, Raymond E. Goldstein |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Fluid Flow and Transfer Processes
Convection Growth medium biology Fluid Dynamics (physics.flu-dyn) Computational Mechanics Evaporation FOS: Physical sciences Physics - Fluid Dynamics Condensed Matter - Soft Condensed Matter biology.organism_classification 01 natural sciences 6. Clean water 010305 fluids & plasmas chemistry.chemical_compound chemistry Chemical physics FOS: Biological sciences Modeling and Simulation Cell Behavior (q-bio.CB) 0103 physical sciences Soft Condensed Matter (cond-mat.soft) Quantitative Biology - Cell Behavior 010306 general physics Bacteria |
| Popis: | We report a novel form of convection in suspensions of the bioluminiscent marine bacterium $Photobacterium~phosphoreum$. Suspensions of these bacteria placed in a chamber open to the air create persistent luminiscent plumes most easily visible when observed in the dark. These flows are strikingly similar to the classical bioconvection pattern of aerotactic swimming bacteria, which create an unstable stratification by swimming upwards to an air-water interface, but they are a puzzle since the strain of $P.~phosphoreum$ used does not express flagella and therefore cannot swim. Systematic experimentation with suspensions of microspheres reveals that these flow patterns are driven not by the bacteria but by the accumulation of salt at the air-water interface due to evaporation of the culture medium; even at room temperature and humidity, and physiologically relevant salt concentrations, the rate of water evaporation is sufficient to drive convection patterns. A mathematical model is developed to understand the mechanism of plume formation, and linear stability analysis as well as numerical simulations were carried out to support the conclusions. While evaporation-driven convection has not been discussed extensively in the context of biological systems, these results suggest that the phenomenon may be relevant in other systems, particularly those using microorganisms of limited motility. 16 pages, 14 figures, supplementary videos available on request (REG) |
| Databáze: | OpenAIRE |
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