What this work is about, in plain words
After growth stops, the density of an algae culture should remain constant, but in experiments it fluctuates. The authors showed that simple models cannot explain this and outlined what needs to be added to them.
When a microalgae culture grown as a batch runs out of nutrients, its growth stops. The stationary phase begins, and according to simple models culture density should remain constant. In experiments, however, the authors observed fluctuations. The aim of the work was to find out whether such fluctuations are compatible with existing growth models.
The authors compared experimental data on culture density dynamics in the stationary phase with conclusions from the mathematical description of growth in a closed system, where nutrients are not replenished.
According to the authors, density fluctuations in the stationary phase do occur. Yet the accepted equations imply that in a closed system there can be none. So the model is incomplete. To describe the fluctuations, parameters reflecting the structure of the cell and the "bottleneck" of its metabolism — the stage that limits growth — need to be added. The nature of the fluctuations themselves remains an open question: whether they are forced or arise on their own.
The work marks the limit of simple models and the direction of their development.
Limitations. This is a statement of the problem and an analysis of experimental data. The article does not contain a finished model of the fluctuations.