Biogeochemical Cycles

Principles of Biogeochemical Cycles

  • Biogeochemical cycles represent the circular pathways by which elements move through earth’s air, water, soil, rock and living organisms.
  • Cycles include the water cycle, carbon cycle, nitrogen cycle, phosphorus cycle, and sulphur cycle.
  • Each cycle helps make essential nutrients available for organisms, supporting life on Earth.
  • These cyclic pathways help maintain balance within ecosystems and regulate atmospheric gases associated with climate.

Water Cycle

  • This cycle is a series of processes by which water circulates between the Earth’s oceans, atmosphere, and land.
  • The key processes are evaporation, transpiration, condensation, precipitation, runoff, and infiltration.
  • It helps distribute heat around the globe, contributing to Earth’s climate system.

Carbon Cycle

  • The carbon cycle moves carbon, a necessary component of life and crucial greenhouse gas, through the biosphere.
  • Key processes include photosynthesis, respiration, combustion (burning), and decay of organic matter.
  • This cycle helps regulate Earth’s temperature by controlling the amount of carbon dioxide in the atmosphere.

Nitrogen Cycle

  • Nitrogen is necessary for life as it is a component of amino acids and nucleic acids.
  • The nitrogen cycle includes atmospheric nitrogen fixation by bacteria and lightning, synthesis of organic compounds, decay and nitrification, denitrification back to atmospheric nitrogen.
  • This cycle helps maintain soil fertility and is essential for plant growth and development.

Phosphorus Cycle

  • Unlike other cycles, the phosphorus cycle doesn’t have a significant atmospheric component; it circulates between water, soil, and organisms.
  • Essential for ATP and DNA, processes include weathering of rocks, absorption by plants, consumption by animals, and return to soil via waste or decomposition.
  • It plays a critical role in cell function and energy transfer.

Sulphur Cycle

  • Sulphur cycles between the Earth’s atmosphere, living organisms, and the oceans.
  • Includes processes like evaporation from water surfaces, released by volcanoes, decomposition of organic matter, and absorption by plants.
  • Sulphur is crucial for protein synthesis and is a component of certain amino acids and vitamins.