NCERT Notes: Biogeochemical Cycles [Geography Notes For UPSC]

•  Biological Chemical + Geological Process= Biogeochemical
• Energy flows through an ecosystem and is released as heat, but chemical elements are recycled.
• The ways in which an element or compound moves between its several biotic and abiotic forms and locations in the biosphere is called a biogeochemical cycle.
• It is a movement of nutrients and other elements between living and non-living beings.
• The sun is the basic source of energy on which all life depends.
• Life on earth comprises a great variety of living organisms.
• These living organisms exist and survive in a diversity of associations. Such survival encompasses the presence of systemic flows such as flows of energy, water, and nutrients.
• The balance of the chemical elements is maintained by a cyclic movement through the tissues of plants and animals.
• The cycle starts by absorbing the chemical elements by the organism and is returned to the air, water, and soil through decomposition.
• These cycles are largely energized by solar insolation.
• There are two types of biogeochemical cycles:
  • The gaseous cycle
    • In the gaseous cycle, the main reservoir of nutrients is the atmosphere and the ocean.
  • The sedimentary cycle
    • In the sedimentary cycle, the main reservoir is the soil and the sedimentary and other rocks of the earth’s crust.

The important biogeochemical cycles are:

• The Carbon Cycle
• The Nitrogen Cycle
• The Oxygen Cycle
• The Phosphorus Cycle
• The Sulphur Cycle
• The Water Cycle/ Hydrological Cycle
• The Rock Cycle