How does the compensation plane in a lake change with seasons and daily light levels?

In an inland water ecosystem, the compensation plane (or compensation depth) marks the boundary where the rate of photosynthesis is exactly equivalent to the rate of respiration and decomposition. Above this plane lies the photic zone, where primary production exceeds consumption, while below it lies the aphotic zone, where energy consumption exceeds production.1

Because this boundary is defined by the availability of light, the compensation plane is dynamic rather than static. It changes in response to fluctuations in light penetration, which are driven by both daily and seasonal cycles:

• Daily (Diurnal) Changes: As light intensity varies throughout the day, the depth to which sufficient light penetrates for photosynthesis shifts, causing the compensation plane to move vertically.1
• Seasonal Changes: Seasonal variations in solar angle, day length, and water turbidity—often influenced by seasonal thermal patterns and mixing events—alter light penetration, thereby shifting the compensation plane throughout the year.123

Essentially, whenever light availability changes, the depth at which primary production and respiration are balanced must adjust accordingly.1