Chaotic oscillations in a chloroplast system under constant illumination

We show that nonlinear, aperiodic oscillatory behavior can be observed in a chloroplast system by measuring the absorption of light. This behavior dep ends on illumination of the system with light which is absorbed by chloroph yll. The oscillations can be stopped by addition of acetone indicating that chemical reactions are involved. These observations confirm the role of ph otosynthesis. The effect of stirring and the statistics of the oscillating part of the spectrum suggest that the buoyancy of oxygen bubbles formed dur ing photosynthesis is an important part of the mechanism.