1. Cycling of matter
IB Syllabus: 2.5.4
Ch. 4

2. Syllabus Statements
2.5.4: Describe and explain the transfer and transformation of materials as they cycle within an ecosystem

3. Biogeochemical cycles
Nutrients needed for life are continuously cycled between living and nonliving things
Life  Earth  Chemical cycles
Driven by incoming solar energy
Connect past – present – future by recycling chemical compounds
Oxygen, Carbon, Nitrogen, Phosphorous, and water

5. Water Cycle
Collects, purifies and distributes earth’s constant water supply
Evaporation – converts water into vapor
Transpiration – evaporation from plant leaves
Condensation – vapor to liquid
Precipitation – rain, sleet, snow, hail
Infiltration – movement of water into soil
Percolation – flow of water to aquifers
Runoff – movement of water over land surface

6. Hydrologic cycle

7. Water cycle Sun powers the cycle – 84% vapor from ocean
Warmer air holds more water
Relative humidity = amount of water vapor in a mass of air expressed as a % of the maximum the air could support at that temp
Wind and air masses transport water around the earth

8. Water cycle II Precipitation – needs condensation nuclei to occur
Soil dust, volcanic ash, smoke, sea salt, particulates
Some locked in glaciers, most into oceans as surface runoff
Runoff sculpts earth’s surface & transports nutrients
Water purification happens at many steps

9. Hydrologic Cycle
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10. Human Influences
Withdrawing large quantities of fresh water from surface and ground water
Aquifer depletion and saltwater intrusion
Clearing vegetation for agriculture, mining, construction
Increase runoff, flooding, erosion, Decrease infiltration
Modifying water quality
Adding nutrients, changing natural processes

13. Carbon cycle “C” is the basic building block of life
Global gaseous cycle based on CO2
Producers remove CO2 from the atmosphere in photosynthesis
Respiration of organisms puts CO2 back into atmosphere
Organic carbon stored in living tissues and fossil fuel deposits

15. Terrestrial Carbon cycle

16. Carbon storages Organisms store most of the carbon
organic compounds
Sedimentary rocks such as limestone
Carbon reenters cycle when sediments dissolve naturally or by acid rain
Oceans
Gas dissolves into ocean at surface
Removed by marine algae in photosynthesis
Marine organisms
Reaction of CO2 with Ca in organisms to produce CaCO3 for shells and

17. Aquatic Carbon Cycle

18. Human effects Adding Carbon to the Atmosphere
Clearing trees and plants that absorb CO2 through photosynthesis
Burning fossil fuels and wood increasing CO2
Enhance the greenhouse effect
Raise sea level
Disrupt food production
Destroy habitats

19. Nitrogen cycle

20. 1. Nitrogen Fixation
Specialized bacteria convert atmospheric N2 into NH3
N2 + 3 H2  2 NH3
Done by
Cyanobacteria – in soil and water
Rhizobium – bacteria living in root nodules of a variety of legume plants

21. 2. Nitrification A two step process
Ammonia in soil converted to nitrite and nitrate
Aerobic bacteria complete this process
NH3 NO2- (toxic to plants)
NO2- NO3- (easily taken up by plants as nutrient

22. 3. Absorption / Assimilation
Plant roots absorb inorganic nitrogen ions
nitrates, ammonium
Ions used to make nitrogen containing organic molecules
DNA, amino acids, proteins
Animals get nitrogen by eating plants or other plant-eating animals

23. 4. Ammonification
After N has been used in living things and it leaves as waste or death…
Bacterial decay results
Producing
Simpler inorganic compounds like NH3
Water soluble salts containing NH4+

24. 5. Denitrification
Anaerobic bacteria in waterlogged soils and bottom sediments
Convert nitrogen compounds back into gas forms and release into the atmosphere
NH3 NO2- N2
 
NH4+ NO3- N2O

25. Human effects on the N-cycle
Inputs of commercial inorganic fertilizer
Adding NO to the air through combustion of fuels
Enters water cycle  Acid Rain
Removing “N” from the crust by mining
Removing “N” from soil
Harvest crops, irrigation, deforestation
Adding “N” to aquatic systems from runoff

27. The Phosphorous cycle Through water  organisms  earth’s crust
Very little in the atmosphere
Found as phosphate salts in terrestrial rocks and ocean sediments
Into organisms by uptake & assimilation by plants, consumption & assimilation by animals, then animal waste returns it to water or to the land (guano)
Often a limiting factor in plant growth both terrestrial and aquatic

28. Phosphorous cycle

31. Human effects Mining large amounts of phosphate rock
Inorganic fertilizers, Detergents
Reducing available phosphate in tropical forests by removing trees
Soil nutrients washed away w/out trees
Adding excess phosphate to aquatic systems
Runoff of animal waste, commercial fertilizer from farmland, municipal sewage discharge

32. Florida Phosphate mining

33. The sulfur cycle
Most “S” stored underground in rocks and minerals including salts in ocean sediment
Enters the atmosphere from volcanoes, sea spray, decomposition in aquatic habitats
Marine algae may produce DMS sulfur compounds in large quantities
In atmosphere it may mix into hydrologic cycle to form sulfuric acid – acid rain

34. Sulfur cycle

35. Human effects
Burning “S” containing coal and oil for electricity production
2/3 of human SO2 inputs
Refining “S” containing petroleum into gasoline, heating oil, etc.
Smelting of “S” compounds of metallic minerals producing pure metals
Copper, Lead, Zinc

36. Cycle types With all cycles common features allow grouping
Groups based on storages
Sedimentary cycle – major storage in the ground
E.x. phosphorous cycle
Atmospheric cycle – major storage in the atmosphere
E.x. nitrogen cycle

37. You should be able to create a flow diagram of Carbon, Water and Nitrogen cycles

41. http://www. colorado. edu/GeolSci/courses/GEOL1070/chap04/chapter4