As an aside, the growth and survival of an individual is dependent upon obtaining adequate materials from the environment. The Law of Limiting Factors states that the element in least amount relative to needs to individual will limit its growth. A good analogy is a barrel - just as you can only fill a barrel as full as its longest stave, an organisms growth will be dictated by its most limiting factor. The cycling or exchange of elements through the ecosystem is called a bio geo chemical cycle . An element can exist in various forms in the biotic reservoir.
Nutrient elements return to the abiotic reservoir via death, excretion, wastes.
Elements exist in various forms in the abiotic reservoir. Geological activity moves materials through the abiotic reservoir. Movement is typically much slower than through the biotic reservoir. B. Points to consider. See diagram in text.