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. We won't discuss this one directly so check it out in the text. Carbon cycle - an atmospheric cycle . See diagram in text and provided in class.