In the ocean, some bacteria swim and some do not. Who wins and when? To find out, we developed a mathematical model of nutrient competition among bacteria in the ocean and implemented it within a Direct Numerical Simulation of turbulent flow, which takes into account the effect of turbulence on the transport and dispersion of nutrient patches and bacteria. We have found that (i) an optimal swimming speed guarantees the best advantage to swimmers and is broadly in agreement with observed swimming speeds, and (ii) an intermediate turbulence intensity optimally favors motility, because it creates chemical gradients and does not mix them away too rapidly. This approach is flexible, can include multiple other bacterial traits, and represents a promising new ecological framework to understand the evolution of different foraging strategies and the competition for nutrients among bacteria in the ocean
(Previously working on this topic: John Taylor).