Exploring Biology Topics can reveal the incredible complexity and interconnectedness of living systems.
Biogeochemical Cycle – Importance, Types
The biotic resources of the environment include all living organisms including human beings. They may be producers of food (e.g., green plants, autotrophic prokaryotes such as cyanobacteria) or consumers (e.g., animals, fungi, some bacteria, and viruses). Microorganisms too have important roles to perform in the environment.
1. Plants
Green plants are the producers of food for all living beings. The leaves and other green parts of plants synthesize food (e.g., carbohydrates such as sugar and starch; fats and proteins) and release oxygen. This metabolic activity is called photosynthesis and occurs in plant cells, especially in the chloroplasts. The process of photosynthesis needs sunlight and it manufactures food with the help of water absorbed from the soil and carbon dioxide from the atmosphere.
Besides food items, green plants also supply us with various other things such as timber, medicines, clothes, fuel, and even materials for shelter. We already know that all living organisms require oxygen produced by plants during photosynthesis for their survival. Thus plants have great significance – “they can survive without animals but animals cannot survive without the plants”.
Carbon dioxide normally is not regarded as a pollutant but it has two noxious effects: its abundance in the air has a suffocating effect on humans and ecologically it results in global warming.
2. Animals
Animals form another important biotic component of the environment. They depend on the plants for their survival. Indeed animals hold a very intimate and unbreakable relationship with plants.
Both non-living (abiotic) and living (biotic) components of the biosphere constantly interact with each other to form a dynamic yet stable system. Such interactions include the transfer of matter and energy between the different components of the biosphere.
As far as nutrients are concerned, all living organisms require eight elements as nutrients in relatively larger amounts. These include carbon, hydrogen, oxygen, nitrogen, sulphur, phosphorus, potassium, and calcium. Living organisms get the nutrient elements from the lithosphere (mainly soil), hydrosphere, and atmosphere.
The dissipation of energy in some form is always necessary to drive the material cycle.
The nutrient elements derived from the Earth by living organisms, for their growth and metabolism are called biogeochemicals. These biogeochemicals are continuously recycled. The movement of nutrient elements through the living and non-living components of the biosphere is called the biogeochemical cycle of matter. The term ‘biogeochemical cycle’ indicates that chemicals circulate through life (bio) and through Earth (geo) again and again (cycles). ‘Geo’ refers to rocks soil, air, and water of the Earth.
The biogeochemical cycles are also known as nutrient cycles. Each nutrient cycle can also be divided into two compartments or pools:
- reservoir pool, the large, slow-moving, generally non-biological component, and
- labile or cycling pool, a smaller but more active portion, that is exchanged (moving back and forth) rapidly between organisms and their immediate environment.
Many elements have multiple reservoir pools and some such as nitrogen have multiple labile pools.
From the viewpoint of the ecosphere as a whole, biogeochemical cycles fall into two basic groups:
- Gaseous biogeochemical cycles, in which the reservoir is in the atmosphere or the hydrosphere (ocean). Gaseous biogeochemical cycles are quick and relatively perfect systems, as their elements remain in more or less uniform circulation. The four most abundant elements in the living systems – nitrogen, carbon, oxygen, and hydrogen have chiefly gaseous biogeochemical cycles.
- Sedimentary biogeochemical cycles are systems in which the reservoir is in the crust of the Earth. Sedimentary biogeochemical cycles are slow and less perfect systems as their elements may get locked in the reservoir pool and may go out of circulation for long periods. Phosphorus, sulphur, potassium, and calcium have sedimentary biogeochemical cycles.