1. Ecosystem Services o Important environmental benefits that ecosystems provide, such as: Clean air to breathe Clean air to breathe Clean water to drink Clean water to drink Fertile soil in which to grow crops Fertile soil in which to grow crops

3. Overview Natural Biogeochemical Cycles 1. The Carbon Cycle 2. The Nitrogen Cycle 3. The phosphorus Cycle 4. The Sulfur Cycle 5. The Hydrologic Cycle (water cycle)

4. Biogeochemical Cycles o Matter moves between ecosystems, biotic & abiotic environments, and organisms Unlike energy Unlike energy o Biogeochemical cycling involves Biological, geologic and chemical interactions Biological, geologic and chemical interactions o Five major cycles: Carbon, Nitrogen, Phosphorus, Sulfur and Water (hydrologic) Carbon, Nitrogen, Phosphorus, Sulfur and Water (hydrologic)

5. Carbon o All living things are composed of carbon o.037% of the atmosphere (approximately) is composed of carbon as a gas, CO 2 o It is present in the oceans in several forms: o Carbonate- CO2-, and Bicarbonate HCO- 3 3 3 3

6. The Carbon Cycle o The global movement of carbon between the abiotic/biotic environment including the atmosphere, and oceans and organisms o Producers/Trees act as carbon sinks in that they store carbon in their tissues o Consumers eat producers/trees and exhale CO 2 o When all of the above are decomposed by decomposers CO2

7. The Carbon Cycle : Simplified Units are expressed as 10 15 g of carbon. Notice that sedimentary rocks and fossil fuels hold almost all of the worlds carbon…hmm…

8. The Nitrogen Cycle o Nitrogen is crucial to living organisms because it is an essential part of biological molecules such as proteins, and nucleic acids (RNA/DNA) o The atmosphere is composed of 78% nitrogen, N 2, a two-atom molecule o However atmospheric nitrogen, N 2, is unstable and needs to be “fixed” in order for it to be “used” by organisms

9. 5 Steps of the Nitrogen Cycle 1. Nitrogen Fixation: The conversion of atmospheric nitrogen (N 2 ) to ammonia (NH 3 ), performed by nitrogen fixing bacteria. This can happen by combustion, volcanic action, lightning discharges, and industrial processes 2. Nitrification: The conversion of ammonia or ammonium to nitrate, performed by nitrifying bacteria; which employ an enzyme called nitrogenase that helps aid this process.

10. 5 Steps of the Nitrogen Cycle cont… 3. Assimilation: The conversion of inorganic nitrogen (nitrate, ammonia, or ammonium) to the organic molecules of organisms 4. Ammonification: The conversion of organic nitrogen back to ammonia and ammonium ions performed by ammonifying bacteria (circle within the circle) 5. Denitrification: The conversion of nitrate to nitrogen gas, performed by denitrifying bacteria

11. The Nitrogen Cycle Values shown are expressed as 10 12 g of nitrogen/year. The atmosphere holds the largest pool of nitrogen as N 2.

12. The Phosphorus Cycle o Phosporous does not form compounds in the gaspeous phase, and therefore does not enter the atmosphere o It cycles from the land (through erosion of rocks) to the ocean (found in sediments) o It is also found in soils where it is assimilated into plant tissues o Once inside cells phosphorous is used in nucleic acids and ATP (adenosine triphosphate)

13. The Phosphorous Cycle o Phosphorus cycles in aquatic communities much in the same way as it does terrestrial o Humans affect the phospohorous cycle by taking it from one area and using it in another as fertilizers o Example: Corn from Iowa fatten cattle in Illinois, the beef is consumed in New York and the phosphorous enters the NY sewer systems)

14. The Phosphorus Cycle

15. The Sulfur Cycle o There is much uncertainty regarding the involved in the global sulfur cycle o Sulfur gases enter the air through sea spray(sulfates SO 2/4- ), volcanoes (sulfur di/trioxides SO 2 &SO 3), and dust storms from deserts (calcium sulfate CaSO 4 ) o Sulfur comprises a minor part of our atmosphere because it highly reactive as a gas

16. Sulfur Cycle o Humans can release excess sulfur into the atmosphere from power plants, factories, smelting of metal ores and vehicle combustion which can lead to acid rain

17. The Sulfur Cycle

18. The Hydrologic Cycle (water cycle) o Enough said guys… o Know the following terms: evaporation, condensation, precipitation, transpiration, runoff, estuary, and watershed. o Understand the role each of these plays in the Hydrologic Cycle

19. The Water (Hydrologic) Cycle