9/5/14 Agenda

1. 9/5/14 Agenda • Ecology part 1 continued…Biogeochemical cycles (ch 7) • Monitor Ecocolumns with water test stations…continue collecting data • Discuss lab reports

2. The Nitrogen Cycle All living things need nitrogen to make amino acids (proteins) and DNA

3. Nitrogen is found in all living things.

5. The two important steps in the Nitrogen Cycle are: Nitrogen Fixation and Nitrification

6. Nitrogen fixation occurs in three ways: bacteria, lightning, and artificially

7. Nitrogen Fixation, the first step, produces ammonia and ammonium ion

8. Legumes

9. Root Nodules with Nitrogen Fixing Bacteria

10. Nitrification produces nitrite and nitrate ions which can be used by producers (plants)

11. Plant roots absorb nitrates and make proteins (assimilation)

12. Effects of Anthropogenic Activities on the Nitrogen Cycle • Human production of fertilizers make more nitrogen than nature. Figure 3-30

13. Other Anthropogenic effects Burning fossil fuels releases nitric oxides into the atmosphere, thereby making nitric acid and contributing to acid rain

14. The waste products and dead bodies of organisms put nitrogen back into the soil

15. Denitrifying bacteria put nitrogen back into the air as nitrogen gas (N2)

16. The Water Cycle • Three major processes • Evaporation, precipitation, transpiration • Alteration of the hydrologic cycle by humans • Withdrawal of large amounts of freshwater with aquifers at rates faster than nature can replace it • Deforestation, clearing vegetation, and urban pavements increasing runoffs • Increased flooding when wetlands are drained • Pollution of waters

17. Condensation Ice and snow Condensation Transpiration from plants Precipitation to land Evaporation of surface water Runoff Evaporation from ocean Lakes and reservoirs Runoff Precipitation to ocean Increased runoff on land covered with crops, buildings and pavement Infiltration and percolation into aquifer Increased runoff from cutting forests and filling wetlands Runoff Groundwater in aquifers Overpumping of aquifers Water pollution Runoff Ocean Natural process Natural reservoir Human impacts Natural pathway Pathway affected by human activities Fig. 3-15, p. 63

18. Science Focus: Water’s Unique Properties • Properties of water due to hydrogen bonds between water molecules: • Liquid over large temperature range • Changes temperature slowly • High boiling point: 100˚C • Adhesion and cohesion • Expands as it freezes • Solvent • Filters out harmful UV

19. Hydrogen Bonds in Water Slightly negative charge Hydrogen bonds Slightly positive charge Fig. 3-A, p. 64

20. The Sulfur Cycle • Most sulfur found in rocks and deep under ocean sediments • SO2 in the atmosphere • Released by volcanoes • Human activities affect the sulfur cycle • Burn sulfur-containing coal and oil • Refine sulfur-containing petroleum • Convert sulfur-containing metallic mineral ores

21. Sulfur dioxide in atmosphere Sulfuric acid and Sulfate deposited as acid rain Burning coal Refining fossil fuels Smelting Sulfur in animals (consumers) Dimethyl sulfide a bacteria byproduct Sulfur in plants (producers) Mining and extraction Uptake by plants Sulfur in ocean sediments Decay Decay Process Sulfur in soil, rock and fossil fuels Reservoir Pathway affected by humans Natural pathway Fig. 3-20, p. 69

22. The End