Download to read offline
![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.](https://image.slidesharecdn.com/biogeochemicalcycles-240125194239-836a7472/85/BIOGEOCHEMICAL_CYCLES-ppt-20-320.jpg)
BIOGEOCHEMICAL_CYCLES.ppt
- 1.
- 2.
- 3.
- 4.
- 5.
- 6. HYDROLOGIC CYCLE Precipitation to land Transpiration fromplants 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 OFTHE CYCLES AND SPHERES TOGETHER
- 8. HUMAN IMPACTS TOWATER 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.
- 10. MARINE CARBON CYCLE Diffusionbetween 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 Soilwater (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 withinthe 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 Respirationoccurs 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 CARBONCYCLE • 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 Slide38 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 CARBONIS THE BACKBONE OF LIFE!
- 19. NITROGEN CYCLE NO3 – in soil Nitrogen Fixation byindustry 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 STEPSIN 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 NITROGENCYCLE 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.
- 23. PHOTOCHEMICAL SMOG “BAD OZONEDOWN LOW”
- 24. “GOOD OZONE UPHIGH”
- 25. HUMAN IMPACTS ON NITROGENCYCLE 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.
- 27. HUMAN IMPACTS ON NITROGENCYCLE • 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.
- 29.
- 30. HUMAN IMPACTS ON NITROGENCYCLE 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 Slide40 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 Organismsuse 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 MARINESEDIMENTS 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 PHOSPHOROUSCYCLE 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.
- 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 Acidicfog 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 SULFURCYCLE 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.
- 42. HUMAN IMPACTS ONTHE 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 MORECOWS CAN THE EARTH SUPPORT?