The physics is way beyond me, but a new paper by Gary Klindt and colleagues in New Journal of Physics uses Chlamydomonas as a model for flagellar synchronization:

We present a theory of flagellar synchronization in the green alga Chlamydomonas, using full treatment of flagellar hydrodynamics and measured beat patterns. We find that two recently proposed synchronization mechanisms, flagellar waveform compliance and basal coupling, stabilize anti-phase synchronization if operative in isolation. Their nonlinear superposition, however, can stabilize in-phase synchronization for suitable parameter choices, matching experimental observations.

Figure 1 from Klindt et al. 2017. In-phase and anti-phase synchronization. (a) In-phase synchronization at high synchronization strength, corresponding to “breast-stroke swimming” Chlamydomonas. (b) For low synchronization strength, anti-phase synchronization is stable, corresponding to a “free-style” gait.

By comparing model results with experimental measurements, they find that two factors are required to explain flagellar synchronization in Chlamydomonas. Waveform compliance (passive hydrodynamically-driven synchronization) and basal coupling mediated by a physical connection between the basal ends of the flagella both must play a role:

…we have shown that synchronization strengths measured in experiments cannot be explained without basal coupling in the framework of our theory, yet are reproduced for plausible parameter choices assuming such coupling.

Stable links:

Klindt, G. S., C. Rulof, C. Wagner, and B. M. Friedrich. 2017. In-phase and anti-phase flagellar synchronization by waveform compliance and basal coupling. New Journal of Physics 19: 113052. doi: 10.1088/1367-2630/aa9031