Mechanics and Resonance of the Cyanobacterial Circadian Oscillator

TL;DR

This paper models the cyanobacterial circadian oscillator's dynamics, coupling it with Earth's rotation to analyze how historical changes in day length affected its resonance and energy efficiency.

Contribution

It derives a mathematical model of the cyanobacterial oscillator from experimental data and couples it with Earth's rotation to study historical resonance effects.

Findings

Two resonance peaks identified in the oscillator-Earth system.

Cyanobacteria were more energy-efficient during periods with 11-15 hour days.

Energy efficiency peaks align with historical day length changes.

Abstract

Recent experiments elucidated the structure and function of the cyanobacterial circadian oscillator, which is driven by sunlight intensity variation and therefore by Earth's rotation. It is known that cyanobacteria appeared about 3.5 billion years ago and that Earth's rotational speed is continuously decreasing because of tidal friction. What is the effect of the continuous slowdown of Earth's rotation on the operation of the cyanobacterial oscillator? To answer this question we derived the oscillator's equation of motion directly from experimental data, coupled it with Earth's rotation and computed its natural periods and its resonance curve. The results show that there are two resonance peaks of the "cyanobacterial oscillator-rotating Earth" system, indicating that cyanobacteria used more efficiently the solar energy during the geological period in which the day length varied from about 11 to 15 hours and make more efficient use of solar energy at the geological period which started with a day length of 21 hours and will end at a day length of 28 hours.