Photosynthesis, the process by which solar energy enables carbon dioxide and water to be converted to organic compounds (sugars) and oxygen, takes place in the cells of all plants. This fundamental biological process enables producers to create their own biomass. The matter produced thereby is consumed by organisms (animals) from higher trophic levels. The rate of production of matter by photosynthesizing organisms is expressed by a magnitude known as primary production.

The SatBałtyk System provides parameters characterizing both photosynthesis and primary production in the Baltic Sea. Each of these characteristic parameters is discussed in detail below.