A biogeochemical cycle is a pathway through which a chemical substance moves between biotic and abiotic compartments of an ecosystem. The main role of a biogeochemical cycle is to recycle the elements on the earth. Biogeochemical cycle enables the transformation of matter from one form to another form. The byproducts of biogeochemical cycles assist the functioning of ecosystems. The types of elements recycled can be either micronutrients or macronutrients. Some examples of biogeochemical cycles are carbon cycle, nitrogen cycle, phosphorus cycle, water cycle, etc.
Key Areas Covered
Key Terms: Biogeochemical Cycles, Ecosystems, Locality of Nutrients, Macro Nutrients, Micro Nutrients
What are Biogeochemical Cycles
A biogeochemical cycle is a pathway through which conserved matter moves through the biotic and abiotic part of an ecosystem. Two types of elements are recycled by biogeochemical cycles. They are micro elements and macro elements. Micro elements are required in small amounts by living organisms. Boron, copper, molybdenum, etc. are some micronutrients. Macro elements are required in large amounts by living organisms. Carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur are some macro elements. Some biogeochemical cycles are carbon cycle, nitrogen cycle, oxygen cycle, water cycle, phosphorus cycle, sulfur cycle, etc. The water cycle is shown in figure 1.
Why are Biogeochemical Cycles Important
At the ecosystem level, biogeochemical cycles perform a variety of functions.
- Biogeochemical cycles enable the transfer of molecules from one locality to another. This allows the transformation of elements into utilizable forms. As an example, during nitrogen cycle, atmospheric nitrogen is transformed into nitrates.
- Biogeochemical cycles enable the transformation of nutrients from one form to another. This allows the utilization of nutrients in specific forms by a particular organism. As an example, different species of nitrogen-fixing bacteria utilize different forms of nitrogen. Hence, nutrients do not become a limiting factor for growth.
- Biogeochemical cycles facilitate the storage of elements – Different types of nutrient reservoirs are produced by each of the different steps of the biogeochemical cycles.
- Biogeochemical cycles assist in the functioning of ecosystems – The biotic and abiotic components of the ecosystem are linked by the flow of nutrients through biogeochemical cycles. Different types of organisms utilize different levels of nutrients.
Biogeochemical cycles are the pathways through which the flow of elements occur between biotic and abiotic parts of ecosystems. Carbon cycle, nitrogen cycle, water cycle, etc. are some biogeochemical cycles. Biogeochemical cycles are mainly involved in the flow of nutrients through different levels of the ecosystem.
1. “Intro to Biogeochemical Cycles.” Khan Academy, Available here.