Oxygen production is directly related to the rate of photosynthesis. During photosynthesis, oxygen is produced as a byproduct of the light-dependent reactions when sunlight splits water molecules. Therefore, the amount of oxygen released is an indicator of the photosynthesis rate—the more oxygen produced, the higher the rate of photosynthesis. This relationship is often used experimentally by measuring the volume or number of oxygen bubbles produced by aquatic plants to estimate photosynthetic activity. However, very high oxygen concentrations can inhibit photosynthesis through a process called photorespiration, which reduces photosynthetic efficiency under certain conditions.
