Influence of bacteria, diffusion and sheer on micro-scale nutrient patches, and implications for bacterial chemotaxis

被引:41
作者
Blackburn, N [1 ]
Fenchel, T [1 ]
机构
[1] Univ Copenhagen, Marine Biol Lab, DK-3000 Helsingor, Denmark
关键词
bacteria; micro-scale patchiness; chemotaxis; shear;
D O I
10.3354/meps189001
中图分类号
Q14 [生态学(生物生态学)];
学科分类号
071012 ; 0713 ;
摘要
Micro-scale nutrient patches were observed in mixtures of isolates consisting of a protozoan, its prey, and chemotactic bacteria. The patches were shown by swarms of bacteria and the events leading to patches were associated with cell lysis and predation events. In such a form, nutrients are experienced by bacteria as pulses. Simulations showed that patches can be consumed by the bacterial community before being dispersed. As a result, even non-motile bacteria may only ever encounter diffuse patches within a sphere of 2 mm radius. If patches are generated randomly in time and space, it can be advantageous for a bacterium to swim, if only to break this 2 mm barrier. Simulations suggested that chemotaxis can increase a bacterium's exposure to nutrients within a patch, but that the enhancement depends on the size of the patch, due to limitations in sensitivity. The patch size limit for achieving enhancement is similar to 0.1 pmol. Swimming speed is the most important motility parameter influencing efficiency of chemotactic foraging on diffuse patches, with an optimum speed as a function of patch size. Simulations illustrated that shear stretches patches, but that moderate shear does not significantly alter patch volumes within time scales of several minutes. A large proportion of the nutrients within a patch can be encountered by bacteria within that time.
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页码:1 / 7
页数:7
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