Explain Nutrient Cycling and their processes?

Two major processes are common to all ecosystems: nutrient cycling and the flow of energy. These two functions are carried out by the organisms that comprise the communities within an ecosystem. Nutrient cycles are sometimes referred to as biogeochemical cycles, reflecting the fact that chemicals are cycled between biological organisms, and between organisms and the geologic (physical) environment. Nutrient cycling involves the conversion of inorganic compounds into organic compounds through the metabolism of organisms, and then back to the inorganic forms through other metabolic pathways of organisms.

Although nutrients can be continuously recycled, energy cannot. Sunlight energy is captured and converted into a usable form by photosynthetic autotrophs, and then passed to heterotrophs within the food chain. At each conversion, some energy is lost to the system as heat energy. Therefore, an ecosystem requires a constant input of energy from an outside source, such as the sun.

Carbon, hydrogen, oxygen, and nitrogen make up most of the biological molecules found in living organisms. These elements are passed from organism to organism by chemical conversion processes, which occur in the food web, otherwise known as the food chain. They are also converted from non-living forms to living forms by photosynthesis, and from living forms to non-living forms through cellular respiration. The non-living forms of carbon, hydrogen, oxygen, and nitrogen form huge reservoirs in the physical environment. For instance, nitrogen makes up 78% of the atmosphere as N2, and hydrogen comes from water.