Trophic Levels

Primary producers are autotrophic organisms that are capable of fixing solar radiation into biochemical energy, through the process of photosynthesis. Photosynthesis is comprised of a series of enzyme-mediated chemical reactions which result in the combination of carbon dioxide and water into glucose, a simple sugar. This chemical reaction requires an input of energy to proceed, and this energy is provided by red and blue wavelengths of solar radiation, which are captured by the photosynthetic pigment chlorophyll. The fixed-energy content of the glucose can then be utilized to drive a great diversity of other metabolic reactions, which are used to synthesize the myriad other biochemicals that are found in the tissues of primary producers.

Primary producers include green plants, algae, and blue-green bacteria. If the rate of photosynthesis by these organisms exceeds their metabolic requirements, then they are able to grow, and their biomass increases.