BIOGEOCHEMICAL_CYCLES

1. BIOGEOCHEMICAL CYCLES

2. ATMOSPHERE

3. LITHOSPHERE

4. HYDROSPHERE

5. ECOSPHERE

6. HYDROLOGIC CYCLE
Precipitation to
land
Transpiration
from plants
Runoff
Surface runoff
(rapid)
Evaporation
from land Evaporation
from ocean Precipitation to
ocean
Ocean storage
Surface
runoff
(rapid)
Groundwater movement (slow)
Rain clouds
Condensation
Transpiration
Evaporation
Precipitation
Precipitation
Infiltration and
Percolation

7. HYDROLOGIC CYCLE
CONNECTS
ALL OF THE
CYCLES
AND
SPHERES
TOGETHER

8. HUMAN IMPACTS TO WATER
CYCLE
1. Water withdrawal from streams, lakes and
groundwater. (salt water intrusion and groundwater
depletion)
2. Clear vegetation from land for agriculture, mining,
road and building construction. (nonpoint source
runoff carrying pollutants and reduced recharge of
groundwater)
3. Degrade water quality by adding nutrients(NO2, NO3,
PO4) and destroying wetlands (natural filters).
4. Degrade water clarity by clearing vegetation and
increasing soil erosion.

9. Water Quality Degradation

10. MARINE CARBON CYCLE
Diffusion between
atmosphere and ocean
Carbon dioxide
dissolved in
ocean water
Marine food webs
Producers, consumers,
decomposers, detritivores
Marine sediments, including
formations with fossil fuels
Combustion of fossil fuels
incorporation
into sediments
death,
sedimentation
uplifting over
geologic time
sedimentation
photosynthesis aerobic
respiration
Figure 4-29a
Page 78

11. TERRESTRIAL CARBON
CYCLE
photosynthesis aerobic
respiration
Terrestrial
rocks
Soil water
(dissolved
carbon)
Land food webs
producers,
consumers,
decomposers,
detritivores
Atmosphere
(most carbon is in carbon dioxide)
Peat,
fossil fuels
combustion of wood (for
clearing land; or for fuel
sedimentation
volcanic action
death, burial, compaction
over geologic time
leaching
runoff
weathering
Combustion
of fossil
fuels

12. Primary Productivity Connection
• Gross Primary Productivity (GPP) – the rate at
which an ecosystem’s producers capture and store
a given amount of chemical energy as biomass in a
given period of time.
• Net Primary Productivity (NPP) – the rate at
which all the plants in an ecosystem produce net
useful energy; equal to the difference between
energy produced through photosynthesis and
energy used for cellular respiration.

13. PHOTOSYNTHESIS
Photosynthesis: occurs within the chloroplasts of green plants.
The photosynthetic membranes are arranged in flattened sacs
called the thylakoids.
6CO2 + 12H2O C6H12O6 + 6O2 + 6H2O
light
(reactants) (products)
Function: Chemical energy
Storage for cell use

14. CELLULAR RESPIRATION
Cellular Respiration occurs
in light simultaneously with
photosynthesis. It occurs in
the cytoplasm and
mitochondria.
It is the reverse reaction of
photosynthesis.
Function = chemical energy
release
C6H12O6 + 6O2 + 6H2O 6CO2 + 12H2O+
chemical energy

15. HUMAN IMPACTS TO
CARBON CYCLE
• 1. Forest and brush removal has left less
vegetation to absorb CO2 through photosynthesis.
• 2. Burning fossil fuels and wood produces CO2
(greenhouse gas) that flows into the troposphere.
Trapping of CO2 in atmosphere enhances natural
greenhouse effect and may contribute to climate
changes that would disrupt global food
production, wildlife habitats and raise sea level by
melting ice caps.

17. Slide 38
Slide 38
Slide 38
Figure 4-30
Page 79
Year
1850 1900 1950 2000 2030
0
2
3
4
5
6
7
8
9
10
11
12
13
14
CO
2
emissions
from
fossil
fuel
(billion
metric
tons
of
carbon
equivalent)
1
High
projection
Low
projection

18. IMPORTANCE OF CARBON
CYCLE
CARBON IS THE BACKBONE
OF LIFE!

19. NITROGEN CYCLE
NO3
–
in soil
Nitrogen
Fixation
by industry for
agriculture
Fertilizers
Food Webs
On Land
NH3, NH4
+
in soil
1. Nitrification
bacteria convert NH4
+
to nitrate (NO2
–)
loss by
leaching
uptake by
autotrophs
excretion,
death,
decomposition
uptake by
autotrophs
Nitrogen Fixation
bacteria convert N2 to
ammonia (NH3) ; this
dissolves to form ammonium
(NH4
+)
loss by
leaching
Ammonification
bacteria, fungi convert the
residues to NH3 , this
dissolves to form NH4
+
2. Nitrification
bacteria convert NO2
-to
nitrate (NO3
-)
Denitrification
by bacteria
Nitrogenous Wastes,
Remains In Soil
Gaseous Nitrogen (N2)
in Atmosphere
NO2
–
in soil
© 2004 Brooks/Cole – Thomson Learning

20. NITROGEN CYCLE
MAJOR STEPS IN NITROGEN CYCLE
• 1. Nitrogen fixation by cyanobacteria or Rhizobium
bacter.
• 2. Ammonification by decomposers and/or nitrogen
fixing bacteria.
• 3. Nitrification by bacteria (NO2 [toxic to plants]to
NO3 [useable by plants]).
4. Assimilation (used by plants) OR Denitrification by
anaerobic bacteria in waterlogged soils or bottom of
lakes convert NH3 and NH4 back to NO2 and NO3
ions and then into N2 and NO2 gas to atmosphere.

21. HUMAN IMPACTS ON
NITROGEN CYCLE
1. WORLD War II, German chemist Fritz Haber developed the
Haber Process and won the Nobel Prize. He developed
Commercial inorganic fertilizer in the laboratory. This was to
solve global famine problems!
N2 + 3H2 2NH3
2. Emit large quantities of NOx into the atmosphere when we burn
any fuel. (NO + O2 2NO). The nitric oxide then reacts
in the atmosphere with oxygen and water vapor to form nitric
acid (HNO3) = acid deposition. This damages and weakens
trees and interferes with aquatic ecosystems. It also creates
photochemical smog known as ozone near the ground.

22. ACID DEPOSITION

23. PHOTOCHEMICAL SMOG
“BAD OZONE DOWN LOW”

24. “GOOD OZONE UP HIGH”

25. HUMAN IMPACTS ON
NITROGEN CYCLE CONT.
• N2O gas is released into the atmosphere by
anaerobic bacteria on livestock wastes and
commercial fertilizers applied to the soil.
These act as greenhouse gases and when
N2O reaches the stratosphere it contributes
to ozone (O3) depletion.

26. OZONE DEPLETION

27. HUMAN IMPACTS ON
NITROGEN CYCLE
• Remove nitrogen from Earth’s crust when we mine for
nitrogen-containing minerals for fertilizers (ammonium
nitrate (NH4NO3).
• Deplete nitrogen from topsoil by harvesting nitrogen-
rich crops (soybeans, alfalfa).
• Leach water-soluble NO3 ions from soil through
irrigation.
• Remove nitrogen from topsoil when we burn grasslands
and clear forests before planting crops while releasing
NOx into atmosphere.

28. SLASH AND BURN

29. “SEDIMENT KILLS REEFS”

30. HUMAN IMPACTS ON
NITROGEN CYCLE CONT.
• Cultural Eutrophication – adding of excess
nutrients of NO2, NO3, and PO4, from
agricultural runoff (fertilizer and animal
waste), discharge of municpal sewage, and
deposition of nitrogen compounds from the
atmosphere.

31. Slide 40
Slide 40
Slide 40
Figure 4-32
Page 81
1920 1940 1960 1980 2000
Global
nitrogen
(N)
fixation
(trillion
grams)
0
50
100
150
200
Year
Nitrogen fixation by natural processes

32. IMPORTANCE OF NITROGEN
CYCLE
Organisms use nitrogen to make vital organic
compounds such as amino acids, proteins, DNA, and
RNA.
In both terrestrial and aquatic ecosystems, nitrogen is
typically in short supply and limits the rate of
primary production = LIMITING FACTOR!

33. PHOSPHOROUS CYCLE
GUANO
FERTILIZER
ROCKS
LAND
FOOD
WEBS
DISSOLVED
IN OCEAN
WATER
MARINE
FOOD
WEBS
MARINE SEDIMENTS
weathering
agriculture
uptake by
autotrophs
death,
decomposition
sedimentation settling out weathering
leaching, runoff DISSOLVED IN
SOIL WATER,
LAKES, RIVERS
uptake by
autotrophs
death,
decomposition
mining
mining
excretion
excretion
uplifting over
geologic time

34. HUMAN IMPACTS TO
PHOSPHOROUS CYCLE
1. Humans mine LARGE quantities of phosphate rock to use in
commercial fertilizers and detergents. Phosphorous is NOT
found as a gas, only as a solid in the earth’s crust. It takes
millions to hundreds of millions of years to replenish.
2. Phosphorous is held in the tissue of the trees and vegetation, not
in the soil and as we deforest the land, we remove the ability for
phosphorous to replenish globally in ecosystems.
3. Cultural eutrophication – ad excess phosphate to aquatic
ecosystems in runoff of animal wastes from livestock feedlots,
runoff of commercial phosphate fertilizers fro cropland, and
discharge of municipal sewage.

35. CULTURAL
EUTROPHICATION

36. IMPORTANCE OF
PHOSPHOROUS CYCLE
• 1.Phosphorous is an essential nutrient of both plants and
animals.
• 2. It is part of DNA molecules which carry genetic
information.
• 3. It is part of ATP and ADP) that store chemical
energy for use by organisms in cellular respiration.
• 4. Forms phospholipids in cell membranes of plants
and animal cells.
• 5. Forms bones, teeth, and shells of animals as calcium
phosphate compounds.

38. SULFUR CYCLE
Sulfur
Hydrogen
sulfide
Sulfate salts
Plants
Acidic fog and
precipitation
Ammonium
sulfate
Animals
Decaying
matter
Metallic
sulfide
deposits
Ocean
Dimethyl
sulfide
Sulfur dioxide Hydrogen
sulfide
Sulfur trioxide Sulfuric acid
Water
Ammonia
Oxygen
Volcano
Industries

39. HUMAN IMPACTS TO
SULFUR CYCLE
Approximately 1/3 of all sulfur emitted into
atmosphere comes from human activities.
• 1. Burning sulfur containing coal and oil to
produce electric power (SOx = acid deposition).
• 2. Refining petroleum – (SOx emissions)
• 3. Smelting to convert sulfur compounds of
metallic minerals into free metals (Cu, Pb, Zn)
• 4. Industrial processing.

40. IMPORTANCE OF SULFUR
CYCLE
1. Sulfur is a component of most proteins and some vitamins.
2. Sulfate ions (SO4
2- ) dissolved in water are common in
plant tissue. They are part of sulfur-containing amino
acids that are the building blocks for proteins.
3. Sulfur bonds give the three dimensional structure of amino
acids.
4. Many animals, including humans, depend on plants for
sulfur-containing amino acids.

41. ROCK CYCLE

42. HUMAN IMPACTS ON THE
ROCK CYCLE
• 1. Humans are excavating minerals and removing
rock material. It takes millions of years for rock
to form.
• 2. Humans remove sediments for building
materials. This removes sediments that may form
sedimentary rocks in the future.
• 3. Humans are filling in wetlands (peatlands),
area that will form future coal beds.

43. HOW MANY MORE COWS
CAN THE EARTH SUPPORT?