6.2C Biological carbon

• Biological Carbon:

  • 20 - 30% of global carbon is stored as dead organic matter in soils for years, decades or even centuries in colder climates or wetland environments
  • Any carbon that is not stored is returned to the atmosphere by biological weathering over several years
  • As all plants are made of carbon, any plant loss to the ground (litter fall) means a transfer of carbon to the soil
• The capacity of the soil to store organic carbon depends on:

  • Climate influences plant growth and microbial and detritivore activity e.g., rapid decomposition happens at higher temperatures and areas with high rainfall have an increased potential carbon storage than the same soil in areas with lower rainfall
  • Soil type - clay-rich soils have a higher carbon content than sandy soil as clay protects carbon from decomposition
  • The use and management of soils - globally, soils have lost 40-90 billion tonnes (Gt) of carbon since 1850, through cultivation and disturbance