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Cycling of matter IB Syllabus: 2.5.4 Ch. 4.

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Presentation on theme: "Cycling of matter IB Syllabus: 2.5.4 Ch. 4."— Presentation transcript:

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 To view this animation, click “View” and then “Slide Show” on the top navigation bar.

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

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