The four nutrients that cycle through all of Earth's spheres and organisms are: carbon, nitrogen, phosphorus, and sulfur. These nutrients are essential to life and are continually re-used and recycled through the Earth's different spheres: the biosphere, atmosphere, hydrosphere, and geosphere. These elements move through different spheres (geosphere, atmosphere, hydrosphere, biosphere) via diverse processes like:Photosynthesis: Plants and algae capture sunlight and CO2 (carbon) to make food (organic matter), releasing oxygen into the atmosphere. Nutrient cycles in the biosphere are the processes by which certain elements are able to move through the earth and its systems such as the biosphere. The biosphere includes all components of the earth that are living, which is all plants, animals, fungi, protists, bacteria and archaea. Elements such as carbon, nitrogen, oxygen, and hydrogen are recycled through abiotic environments including the atmosphere, water, and soil. Since the atmosphere is the main abiotic environment from which these elements are harvested, their cycles are of a global nature. Nutrient cycling refers to the transfers, chemical transformations, and recycling of nutrients in ecosystems. A nutrient budget is a quantitative estimate of the rates of nutrient input and output to and from an ecosystem, as well as the amounts present and transferred within the system. The nutrient cycle is a system where energy and matter are transferred between living organisms and non-living parts of the environment. This occurs as animals and plants consume nutrients found in the soil, and these nutrients are then released back into the environment via death and decomposition. Cycling of nutrients is very essential for life, between organisms and the environment. It is an ecosystem service as it is a process that naturally takes place on the earth. The food chain and food web control the nutrient cycle and convert from the inorganic nutrients to the organic nutrients or vice versa.