Coupled with the release of oxygen in photosynthesis is the creation of bi-carbonate ions which cause a steep rise in pH .
This is matched in darkness as carbon dioxide is released through respiration which substantially lowers the pH .
Coupled with the release of oxygen in photosynthesis is the creation of bi-carbonate ions which cause a steep rise in pH and this is matched in darkness as carbon dioxide is released through respiration which substantially lowers the pH .