1. Biogeochemical Cycles

2. Biogeochemical Cycles
describe the flow of essential elements from the environment through living organisms and back into the environment.

3. Fig 4.5 Periodic table of the elements.
© 2003 John Wiley and Sons Publishers

4. D. T. Krohne, General Ecology

5. Fig 4.6 Idealized diagram of the geologic cycle, which includes the tectonic, hydrologic, rock and biogeochemical cycles.
Fig 4.6 Idealized diagram of the geologic cycle, which includes the tectonic, hydrologic, rock and biogeochemical cycles.
© 2003 John Wiley and Sons Publishers

6. CO2 & CH4
15%/year
Modified from D. T. Krohne, General Ecology

7. Hydrological Cycle

8. Hydrological Cycle (water cycle)
1. Reservoir – oceans, air (as water vapor), groundwater, lakes and glaciers; evaporation, wind and precipitation (rain) move water from oceans to land
2. Assimilation – plants absorb water from the ground, animals drink water or eat other organisms which are composed mostly of water
3. Release – plants transpire, animals breathe and expel liquid wastes

9. Hydrological Cycle
1. Reservoir – oceans, air (as water vapor), groundwater, lakes and glaciers; evaporation, wind and precipitation (rain) move water from oceans to land.
2. Assimilation – plants absorb water from the ground, animals drink water or eat other organisms which are composed mostly of water.
3. Release – plants transpire, animals breathe and expel liquid wastes.

10. Carbon Cycle

11. Carbon Cycle (carbon is required for building organic compounds)
1. Reservoir – atmosphere (as CO2), fossil fuels (oil, coal), durable organic materials (for example: cellulose).
2. Assimilation – plants use CO2 in photosynthesis; animals consume plants.
3. Release – plants and animals release CO2 through respiration and decomposition; CO2 is released as wood and fossil fuels are burned.

12. Fig Idealized diagram illustrating photosynthesis for a green plant (tree) and generalized reaction.
Fig Idealized diagram illustrating photosynthesis for a green plant (tree) and generalized reaction.
© 2003 John Wiley and Sons Publishers

14. Carbon Cycle
1. Reservoir – atmosphere (as CO2), fossil fuels (oil, coal), durable organic materials (for example: cellulose).
2. Assimilation – plants use CO2 in photosynthesis; animals consume plants.
3. Release – plants and animals release CO2 through respiration and decomposition; CO2 is released as wood and fossil fuels are burned.

15. Fig 4.17 Global flux of carbon, 1850-1990.
Fig Global flux of carbon, Modified after Woods Hole, “The Missing Carbon Sink, 2000, accessed July 5, 2000.
© 2003 John Wiley and Sons Publishers

16. Nitrogen Cycle

17. 50% fertilizer
(Bacteria)
Modified from D. T. Krohne, General Ecology

18. Nitrogen Cycle (Nitrogen is required for the manufacture of amino acids and nucleic acids)
1. Reservoir – atmosphere (as N2); soil (as NH4+ or ammonium, NH3 or ammonia, N02- or nitrite, N03- or nitrate

19. Nitrogen Cycle
2. Assimilation – plants absorb nitrogen as either NH4+ or as N03-, animals obtain nitrogen by eating plants and other animals. The stages in the assimilation of nitrogen are as follows:
Nitrogen Fixation: N2 to NH4+ by nitrogen-fixing bacteria (prokaryotes in the soil and root nodules), N2 to N03- by lightning and UV radiation.
Nitrification: NH4+ to N02- and N02- to N03- by various nitrifying bacteria.

20. Nitrogen Cycle
3. Release – Denitrifying bacteria convert N03- back to N2 (denitrification); detrivorous bacteria convert organic compounds back to NH4+ (ammonification); animals excrete NH4+ (or NH3) urea, or uric acid.

21. Nitrogen Cycle
1. Reservoir – atmosphere (as N2); soil (as NH4+ or ammonium, NH3 or ammonia, N02- or nitrite, N03- or nitrate
2. Assimilation – plants absorb nitrogen as either NH4+ or as N03-, animals obtain nitrogen by eating plants and other animals.
3. Release – Denitrifying bacteria convert N03- back to N2; detrivorous bacteria convert organic compounds back to NH4+ ; animals excrete NH4+, urea, or uric acid.

22. Effects of increased use of
Critical Thinking Issue – How are Human Activities Affecting the Nitrogen Cycle?
Effects of increased use of
nitrogen fertilizer:
Increased nitric acid in soil:
Leaching of magnesium and potassium
Increased aluminum levels
Plant root damage
Changes in microbe communities
Fish kills
Eutrophication of water bodies
Nitrates in drinking water
Global effects on plant based CO2 uptake
Critical Thinking Issue – How are Human Activities Affecting the Nitrogen Cycle?
© 2003 John Wiley and Sons Publishers

23. Phosphorus Cycle

24. D. T. Krohne, General Ecology D. T. Krohne, General Ecology
Gaseous
phase
Modified from D. T. Krohne, General Ecology

25. Phosphorus Cycle (Phosphorus is required for the manufacture of ATP and all nucleic acids)
1. Reservoir – erosion transfers phosphorus to water and soil; sediments and rocks that accumulate on ocean floors return to the surface as a result of uplifting by geological processes
2. Assimilation – plants absorb inorganic PO43- (phosphate) from soils; animals obtain organic phosphorus when they plants and other animals
3. Release – plants and animals release phosphorus when they decompose; animals excrete phosphorus in their waste products

26. Phosphorus Cycle
Reservoir – erosion transfers phosphorus to water and soil; sediments and rocks that accumulate on ocean floors return to the surface as a result of uplifting by geological processes
Assimilation – plants absorb inorganic PO43- (phosphate) from soils; animals obtain organic phosphorus when they plants and other animals
Release – plants and animals release phosphorus when they decompose; animals excrete phosphorus in their waste products

27. Effects of Human Activities on the Sulfur Cycle
We add sulfur dioxide to the atmosphere by:
Burning coal and oil
Refining sulfur containing petroleum.
Convert sulfur-containing metallic ores into free metals such as copper, lead, and zinc releasing sulfur dioxide into the environment.

28. Acidic fog and precipitation
Water
Sulfur
trioxide
Sulfuric acid
Acidic fog and precipitation
Ammonia
Ammonium
sulfate
Oxygen
Sulfur dioxide
Hydrogen sulfide
Plants
Dimethyl sulfide
Volcano
Industries
Animals
Ocean
Sulfate salts
Figure 3.32
Natural capital: simplified model of the sulfur cycle. The movement of sulfur compounds in living organisms is shown in green, blue in aquatic systems, and orange in the atmosphere. QUESTION: What are three ways in which your lifestyle directly or indirectly affects the sulfur cycle?
Metallic
sulfide
deposits
Decaying matter
Sulfur
Hydrogen sulfide
Fig. 3-32, p. 78

29. Ecosystems and the Gaia Hypothesis

30. Ecosystem defined: a community of organisms and it’s corresponding abiotic environment through which matter cycles and energy flows
Wide variation in ecosystems
Boarders can be well defined or vague
Can be natural or artificial, managed or wild
Wide range in scale
Common to all ecosystems: energy flow and cycling of matter

31. Gaia Hypothesis(es) This alteration has allowed life to persist
Life has greatly affected the planetary environment
This alteration has allowed life to persist
The Earth is a “super-organism” - Life controls the environment in a fashion that is equivalent to the way an organism controls its various systems
Evolution?

33. Biogeochemical cycles of other minerals, such as calcium and magnesium, are similar to the phosphorus cycle.