Primary productivity refers to the rate at which plants, algae and some bacteria convert sunlight into organic matter through photosynthesis. This process is considered as one of the most important sources of energy for all living beings on earth since it provides food for herbivores and serves as a source of oxygen production. Primary productivity can also refer to the rate at which an ecosystem produces biomass, which includes not only plants but also animals that are directly or indirectly dependent on them. In essence, primary productivity is the foundation upon which all other life in an ecosystem depends and it plays a critical role in maintaining the balance of nature.