Cycle
Abiotic
reservoir
Water
Fresh water
(surface or
ground
water)
Carbon
Why is cycle
necessary?
water is
essential for
maintaining
homeostasis
and many
chemical
reactions in
plants and
animals
CO2 in
Carbon is
atmosphere fundamental
element in
all biological
molecules
Key processes
Description
Photosynthesis
H2O is
essential
reactant in PS
Evaporation
out of leaves
Transpiration
Urination,
exhalation,
sweating
Photosynthesis
Cell Respiration
Nitrogen
Phosphorus
N2 in
Nitrogen is a
atmosphere key element
in proteins
and nucleic
acids
PO43- in soil
and
dissolved in
water
Phosphorus
is a key
element in
nucleic acids
Burning fossil
fuels
Nitrogen
fixation
Nitrification
Abiotic By whom if
or
biotic
Biotic
Biotic
Biotic
Plants
Biotic
Animals
Carbon from Biotic
CO2 is used to
make
carbohydrates
C6H12O6
CO2 is a
Biotic
product of CR
and released
back into
atmosphere
Abiotic
Photoautotrophs
(e.g. plants,
phytoplankton)
Plants, animals,
and
decomposers
(bacteria and
fungi)
biotic
bacteria
biotic
bacteria
Denitrification
biotic
bacteria
ammonification
biotic
bacteria
biotic
plants
Assimilation
Nitrogen
containing
compounds
(NH4+ and
NO3-) are
made into
proteins and
nucleic acids
Assimilation
Phosphates
are used to
make
nucleotides