Fig. 4.

Bacterial growth in a seascape of lysing diatom, illustrating the advantage of motility at high lysis encounter rates and high bacterial concentrations. Three characteristic environmental conditions are shown: typical coastal seawater, a phytoplankton bloom, and a bloom collapse. (A–C) Mean population uptake for motile and nonmotile cells, expressed in new cell carbon equivalents per day, as a function of the background concentration of nonmotile bacteria, B₀. For all panels, the motile:nonmotile cell number ratio was 1:10 (γ = 0.1). Shaded pink areas indicate motile population benefits after subtracting costs for swimming, for a range of assumed swimming velocities and efficiencies (SI Materials and Methods).