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Molecular transport phenomenon of particles and mixing : building blocks of experimental ecology in oceans ?
The chaotic laminar advection of colloids in presence of salt is investigated experimentally with microfluidic technology. As long as salt contrasts hold, colloids are carried along saline gradients much faster than the brownian motion. At larger scale, such synergy between salt and colloids give non trivial effects of the co-mixing of these species. Depending how the salt is introduced in the microchannel, we are able to control the chaotic colloidal mixing efficiency. For instance, colloids can be mixed as fast as molecules are. These results open new experimental investigation of microbial ecological issues since chemotactic bacteria in oceans move along nutrient gradients in mixing turbulent flows in oceans. I will present how microfluidic technology and a recent deeper physical insight into bacterial population allow such investigation.