Biogeochemical Cycles

1. Biogeochemical Cycles Mrs. Stewart Biology

2. CLE 3210.3.4 Describe the events which occur during the major biogeochemical cycles.You will know you have mastered this standard when:You can predict how changes in a biogeochemical cycle can affect an ecosystem

3. Objectives: • Analyze the flow of nutrients in each biogeochemical cycle. • Evaluate the impact that humans have on the biogeochemical cycles.

4. Why do we recycle? • Think – Pair - Share

5. What sustains life on Earth? • Solar energy • The cycling of matter, energy & nutrients • Gravity

6. Two Secrets of Survival: Energy Flow and Matter Recycle • An ecosystem survives by a combination of energy flow and matter recycling.

7. MATTER CYCLING IN ECOSYSTEMS • Nutrient Cycles: Global Recycling • Global Cycles recycle nutrients through the earth’s air, land, water, and living organisms. • Nutrients - the elements and compounds that organisms need to live, grow, and reproduce.

8. Macromolecule Review • What element does every organic organism contain? • What are the 5 major elements that create all the macromolecules? Carbon Carbon Hydrogen Oxygen Nitrogen Phosphorous

9. Think – Pair – Share • What would happen to these elements if they were only capable of being used once? • Think about every time an organism is created and/or destroyed They would begin disappearing (dwindling in supply) – like fossil fuels

10. Biogeochemical Cycles • These are just illustrations or representations to show how substances move through air, water, soil, rock and living organisms.

11. Decomposition • Decomposers: • ultimately responsible for recycling of chemical nutrients • releasing the nutrients in detritus • This makes nutrients available again to the autotrophs in the ecosystem

12. Recycling • What nutrients get recycled? • Carbon Dioxide • Oxygen • Water • Carbon • Nitrogen • Phosphorous

13. Water Cycle

14. Movement of Water • 4 important processes: • Evaporation – adds water as vapor to atmosphere (heat) • Bodies of water, soil, animal bodies, etc. • Transpiration – water evaporates from the leaves of plants • Condensation- Water vapor cools and “condenses” back into liquid droplets. • Precipitation– water released from the atmosphere (temperature, air pressure) • Rain, snow, sleet, hail or fog

15. Water Cycle

16. Think-pair-share • What human activities effect the water cycle? • What do we do as humans that could have positive or negative effects on this cycle

17. Effects of Human Activities on Water Cycle • We alter the water cycle by: • Withdrawing large amounts of freshwater. • Clearing vegetation and eroding soils. • Polluting surface and underground water. • Contributing to climate change. • How do these changes affect the surrounding ecosystems?

18. Objectives: • Analyze the flow of nutrients in each biogeochemical cycle. • Evaluate the impact that humans have on the biogeochemical cycles.

19. Carbon Cycle

20. Photosynthesis vs Cellular Respiration • Photosynthesis absorbs CO2 from the atmosphere/biosphere and releases O2 • Cellular respiration absorbs O2 from the atmosphere/biosphere and releases CO2

21. Carbon is found in 5 major places: • Living and dead organisms • Carbon Dioxide (CO2) in atmosphere • Organic matter in the soil • Fossil fuels and rock deposits • Oceans – dissolved CO2 and shells

22. Do these plants contain Carbon? What happens to the carbon now?

23. Where is the carbon?

24. Think-pair-share • What human activities effect the Carbon-Oxygen cycle? • What do we do as humans that could have positive or negative effects on this cycle

25. Effects of Human Activities on Carbon Cycle • We alter the carbon cycle by adding excess CO2 to the atmosphere through: • Burning fossil fuels. • Clearing vegetation faster than it is replaced.

26. CFCs • Chloro-Fluoro-Carbons • Carbon, chlorine, fluorine • Are man made and used in: air-conditioning, refrigeration, blowing agents in foams, insulations and packing materials, propellants in aerosol cans, and as solvents. • When exposed to UV rays, chlorine is released and damages ozone layer

27. How do those changes affect the surrounding ecosystems?

28. Bell work • Grab your Plickers card up front. • Come to me to get your test grade!

29. Objectives: • Analyze the flow of nutrients in each biogeochemical cycle. • Evaluate the impact that humans have on the biogeochemical cycles.

30. Nitrogen Cycle

32. Nitrogen Uses: • Proteins • Enzymes, skin, muscles, etc. • Nucleic Acids • DNA • RNA

33. Forms of Nitrogen • Nitrogen is found in many forms in the atmosphere / ecosystem • N2 = nitrogen gas (79% of atmosphere) • N2O = nitrous oxide • NH3 = ammonia • NH4 = ammonium • NO3 = nitrate • NO2 = nitrite

34. Nitrogen Fixation • Converting N2 gas to nitrate (only usable form of nitrogen for most plants) • 2 types: • Natural = lightning, fires and bacteria • Human = fossil fuel combustion, fertilizer manufacturing

35. Nitrogen-fixing bacteria • bacteria that transform Nitrogen gas into a usable form (Nitrate) • Live in the soil • May live in the swellings on the roots of some plants (ex. Beans, peas, clover) • These plants provide sugars for the bacteria, and the bacteria provide usable nitrogen.

36. Recycling Nitrogen • Where is Nitrogen found? • Dead organisms (as proteins & nucleic acids) • Urine & dung • Decomposers: break down and release Nitrogen as NH3 (ammonia)

37. Nitrogen Processes • Ammonification – converting NH3 (ammonia) to NH4 (ammonium) • Nitrification – converting NH4 (ammonium) into NO2 (nitrite) or NO3 (nitrates) • Denitrification – anaerobic bacteria break down NO3 (nitrates) and release N2 (nitrogen gas) into the atmosphere

38. Nitrogen Sources: • Plants = Nitrates from the soil • Use to form proteins • Animals = eating plants/organisms and digesting the proteins and nucleic acids • Humans = have doubled the amount of fixed N2 in the atmosphere in the last 100 years. • HOW?

39. Too much of a good thing? • Too much nitrogen in aquatic ecosystems results in: • Eutrophication = excess nutrients stimulate plant growth (algal blooms); when these plants die, decomposers use up the available oxygen during decomposition.

40. Eutrophication

41. Nitrogen Cycle

42. Think-pair-share • What human activities effect the Nitrogen cycle? • What do we do as humans that could have positive or negative effects on this cycle • 2 minutes

43. Effects of Human Activities on the Nitrogen Cycle • We alter the nitrogen cycle by: • Adding gases that contribute to acid rain. • Adding nitrous oxide to the atmosphere through farming practices which can warm the atmosphere and deplete ozone. • Contaminating ground water from nitrate ions in inorganic fertilizers. • Releasing nitrogen into the troposphere through deforestation.

44. Effects of Human Activities on the Nitrogen Cycle • Human activities such as production of fertilizers now fix more nitrogen than all natural sources combined.

45. How does this affect the surrounding ecosystems? • Acid rain • creation of ground level ozone • groundwater contamination • eutrophication.

46. Exploring the Nitrogen Cycle Activity

47. Objectives: Analyze the flow of nutrients in each biogeochemical cycle. Evaluate the impact that humans have on the biogeochemical cycles.

48. Phosphorus Cycle

49. Overview • Movement of phosphorus from the environment, to organisms, and back to the environment • Slow process • Normally does not occur in atmosphere because phosphorus rarely occurs as a gas

50. Phosphorus Uses: • Essential material for animals • Form bones, teeth, molecules (DNA/RNA) Where do organisms get phosphorus? • Plants = absorb from soil and water • Animals = eating plants & other organisms