MCB 150 Lithoecosphere

• Litho-Ecosphere


  • Habitats occurring as land masses consisting of rocks and soils and as sediments
  • Most common environment
• Classification of rocks


  • Igneous
  • Sedimentary
  • Metamorphic
• Minerals


  Inorganic compounds, usually crystalline but sometimes amorphous, of specific chemical composition and structure
• Rocks are massive, solid, inorganic matter consisting of usually two or more intergrown minerals
• Factors important for soil formation

  • Climate
  • Time - non-renewable
  • Topography
  • Organism - biological processes like phototrophic organisms produce biofilm which will introduce organic acids that could then breakdown rocks into soil
  • Parent material - rock
• Soil


  Product resulting from weathering of rocks due to physical, chemical and biological processes
• Components of soil


  • Mineral soil - weathering of rock + inroganic materials (high mineral content)
  • Organic soil - sedimentation in bods and marshes (high organic matter)
• Typical soil is composed of 50% solid portion and 50% pore space
• Soil profile


  Distinct horizons resulting from the weathering process

  
• Soil horizons


  • O1 - recognizable organic matter
  • O2 - decomposed organic matter
  • A
  • E
  • B
  • C
  • R

  
• Microorganisms are commonly found in O, A, E, B horizons
• Piezophilic microorganisms


  Pressure loving organisms, resistant in high pressure
• Soil separates


  • Sand (2.00 – 0.05 mm and 11 cm^2/g)
  • Silt (0.05 – 0.002 mm and 454 cm^2/g)
  • Clay (< 0.002 mm and 8x10^6 cm^2/g)
• Methods to determine soil texture

  • Roll method
  • Feel method
  • Hydrometer method
• Soil water


  Referred to as soil solution or soil mixture distributed in distinct zones among soil particles
• Types of soil water


  • Pellicular water (Hydroscopic or Matric) - water that is absorbed on the surface of the soil particles; not available for use of any organism
  • Capillary water - water available in the pores; may be used by microorganisms and plants
  • Gravitational water - water present in pores which can percolate down the water column as affected by the force of gravity; also available for use of organisms
• Importance of soil water


  As nutrient, reactant for biochemical reactions, as solvent, needed for organic matter decomposition
• Sand


  • Soil remains loose and single grained
  • Can only be heaped into a pyramid
• Loamy sand


  • The soil contains sufficient silt and clay to become somewhat cohesive
  • Can be shaped into a ball that easily falls apart
• Silt loam


  • Same as for loamy sand
  • Can be shaped by rolling into a short, thick cylinder
• Loam


  • About equal sand, silt, and clay
  • Soil can be rolled into a cylinder about 15 cm long that breaks when bent
• Clay loam


  • As for loam
  • Soil can be bent into a U, but no further, without being broken
• Light clay


  • Soil can be bent into a circle that shows cracks
• Heavy clay


  • Soil can be bent into a circle without showing cracks