Inferring Models of Bacterial Dynamics toward Point Sources
Fig 8
The volcano effect emerges from our model as a consequence of the rapid CA concentration variation near the source.
In A) we show a typical trajectory for a bacterium (starting at the origin) exhibiting erratic behavior near the point source ((1000, 1000, 1000)a denoted by the green star). In B) we show the probability of finding the searcher as a function of radial distance from the source. The resulting density profile—resembling the mouth of a volcano in 2d [36, 37]—has maximal bacterial densities occurring on a ring around the point source. Here we used m = 30, α0/a = 30, σ/a = 1 and X ≡ x/a, Y ≡ y/a, and Z ≡ z/a and stopped the trajectory at 12000 steps. We’ve normalized the value for the density at r−r0 by the volume enclosed in the shell at that distance to ensure that our results are independent of volume.