Photosynthesis is the process which converts light energy into chemical energy.

Photosynthesis has a light-dependent phase and a light-independent (dark) phase. In higher plants, algae, and cyanobacteria, light energy is absorbed in the light-dependent phase by the pigment chlorophyll and used to split water to generate short-term stores of chemical energy – adenosine triphosphate ATP – and reducing potential in the form of nicotinamide adenine dinucleotide phosphate NADPH with the net production of O₂. During the dark phase this chemical energy and reducing potential are converted to synthesize organic matter from atmospheric CO₂ in the form of carbohydrates or sugars through the metabolic pathway called Calvin-Benson cycle. The whole process is what is called oxygenic photosynthesis.

The O2k-PB-Module integrates white, blue or red light sources with tightly controllable light intensities. It enables evaluation of the light-dependent net production of O₂ and light-enhanced dark respiration under controlled O₂ concentrations. By expanding high-resolution respirometry, the O2k-PB-Module advances state-of-the-art research in PhotoBiology.