Download Notes: Biogeochemical Cycles

Biogeochemical Cycles
Biogeochemical Cycles
describe the flow of
elements from the
environment through living
things and back to the
environment.
Biogeochemical Cycles
Reservoirs
places (called reservoirs) where the elements are accumulated or held
Assimilation
Transfer of elements from the abiotic into the biotic
Release
Transfer of elements from the biotic back into the abiotic
Hydrological Cycle
(water cycle)
Reservoirs
Open water - oceans, lakes, rivers……
Water vapor -clouds, fog
Groundwater
Glaciers, snow and ice
Hydrological Cycle
(water cycle)
Assimilation
plants
– absorb water from the ground
animals
– drink water
– eat other organisms which are composed mostly
of water
Hydrological Cycle
(water cycle)
Release
plants
– Transpiration from leaves of plants
animals
– Breathing releases water vapor
– Expel liquid wastes
– Evaporation off the surface of the body
Hydrological Cycle
Carbon Cycle
(carbon is required for building organic compounds)
Reservoir
The atmosphere (as CO2)
Fossil fuels (oil, coal,…)
Organic materials (tissues of plants and animals).
Carbon Cycle
(carbon is required for building organic compounds)
Assimilation
plants
use CO2 in photosynthesis
animals
consume plants or other animals made up
of carbon compounds
Carbon Cycle
(carbon is required for building organic compounds)
Release
plants release CO2 during breathing and
decomposition
animals release CO2 during breathing and
decomposition
CO2 is released during combustion of fossil
fuels and other materials
Carbon Cycle
Nitrogen Cycle
(Nitrogen is required for the manufacture of
amino acids and nucleic acids)
Reservoirs
In the atmosphere (as N2)
In the soil as
NH4+ or ammonium
NH3 or ammonia
N02- or nitrite
N03- or nitrate
Nitrogen Cycle
(Nitrogen is required for the manufacture of
amino acids and nucleic acids)
Assimilation
plants can absorb either NH4+ or N03animals obtain nitrogen by eating plants and
other animals
Nitrogen Cycle
(Nitrogen is required for the manufacture of
amino acids and nucleic acids)
The stages in the assimilation of nitrogen:
Nitrogen Fixation:
Some bacteria turn N2 to NH4+
Lightning and radiation turn N2 to N03Nitrification:
Some bacteria turn NH4+ to N02- then to N03-
Nitrogen Cycle
(Nitrogen is required for the manufacture of
amino acids and nucleic acids)
Release
Denitrifying bacteria change N03- back to N2
Animals excrete NH4+ or NH3 in their urine
Nitrogen Cycle
Phosphorus Cycle
(Phosphorus is required for the manufacture
of ATP and all nucleic acids)
Reservoir
sediment and rocks contain phosphorus. When
they erode, they transfer phosphorus into
the water and soil
Phosphorus Cycle
(Phosphorus is required for the manufacture
of ATP and all nucleic acids)
Assimilation
plants absorb inorganic phosphate from the soil
animals obtain organic phosphorus when they eat
plants or other animals
Phosphorus Cycle
(Phosphorus is required for the manufacture
of ATP and all nucleic acids)
Release
plants release phosphorus when they decompose
animals release phosphorus when they decompose
animals excrete phosphorus in their waste products
Phosphorus Cycle