Outline

2. Outline • Energy flow versus chemical cycles • Carbon • Nitrogen • Phosphorous • Water • Ecosystem services

3. Energy flow through ecosystems Only 5% of the solar energy that arrives on earth is captured by photosynthesis. The energy captured powers life.

4. Trophic levels

5. Energy flow versus Biogeochemical cycles

6. A generalized biogeochemical cycle Consumers Producers Decomposers Abiotic reservoir Geological processes

7. Picture of green plants

8. Carbon cycle Carbon is the currency for energy flow!

9. Carbon cycle Carbon is the currency for energy flow! Carbon cycles through the atmosphere, organisms, soils, and oceans (and rocks at very long time scales)

10. Carbon cycle Carbon is the conduit for energy flow! Carbon cycles through the atmosphere, organisms, soils, and oceans (and rocks at very long time scales) Gaseous, mineral, organic

11. Carbon cycle

12. CO2, C leaching, erosion NPP Soil, plant growth (wood) Ecosystem carbon balance C in =  storage + C out C in >  storage + C out: accumulating C C in =  storage + C out: balanced C C in <  storage + C out: loosing C

13. Carbon stocks Sedimentary rocks > deep oceans > atmosphere Only a small amount in organisms and soils!

14. Picture of forest canopy

15. Nitrogen cycle • N cycles through the atmosphere, organisms, soils and sediments

16. Nitrogen cycle • N cycles through the atmosphere, organisms, soils and sediments • Organically bound N is one of the main constituents of organisms • enzymes for photosynthesis, metabolism • proteins • building blocks of DNA...

17. Nitrogen cycle • N cycles through the atmosphere, organisms, soils and sediments • Organically bound N is one of the main constituents of organisms • enzymes for photosynthesis, metabolism • proteins • building blocks of DNA... • Gaseous, mineral, organic

19. Nitrogen cycle • Although N2 gas makes up 72% of the atmosphere, few organisms can use it. • N is the element that is most likely to limit plant growth

20. Nitrogen cycle • N enters system through biological fixation

21. Picture of N accumulation over primary succession Nitrogen accumulates over primary succession

22. Nitrogen cycle • N enters system through biological fixation • If organisms can fix N, why don’t they take over and fix enough N so that it is no longer limiting to plant growth?

23. Why is N in short supply? • Only a few types of organisms can do it

24. Why is N in short supply? • Only a few types of organisms can do it • Energetically expensive to fix N

25. Why is N in short supply? • Only a few types of organisms can do it • Energetically expensive to fix N • Chemically expensive to fix N

26. Why is N in short supply? • Only a few types of organisms can do it • Energetically expensive to fix N • Chemically expensive to fix N • N can be lost from the system • Leaching • Fire • Erosion

27. Picture of ocean water

28. Hydrological cycle Water cycles through the oceans, fresh waters, atmosphere, and land

29. Hydrological cycle Water cycles through the oceans, fresh waters, atmosphere, and land Gaseous phase and liquid phase

30. Hydrological cycle Evaporation: liquid to gas Transpiration: plant transport of water from the soil to the atmosphere Precipitation: gas to liquid

32. Water inputs to ecosystems • Precipitation • THE major water input to ecosystems • Groundwater (in some ecosystems) • Fog deposition (in some ecosystems)

33. Water balance in ecosystems Inputs = storage + outputs

34. Water balance in ecosystems Soil is like a bucket

35. Water balance in ecosystems Soil is like a bucket • Inputs • Mainly precipitation

36. Water balance in ecosystems Soil is like a bucket • Inputs • Mainly precipitation • Storage • Plants, soil and water bodies

37. Water balance in ecosystems Soil is like a bucket • Inputs • Mainly precipitation • Storage • Plants, soil and water bodies • Outputs • Evaporation • Transpiration • Drainage

38. Hydrological cycle • Over oceans, evaporation >> precipitation • On land, evaporation << precipitation and transpiration • Lakes, rivers, streams, groundwater

40. Ecosystem services Processes by which the environment produces fundamental life-support services enjoyed by humans

41. Ecosystem services • Purification of air and water

42. Ecosystem services • Purification of air and water • Detoxification and decomposition of wastes

43. Ecosystem services • Purification of air and water • Detoxification and decomposition of wastes • Regulation of climate

44. Ecosystem services • Purification of air and water • Detoxification and decomposition of wastes • Regulation of climate • Regeneration of soil fertility

45. Ecosystem services • Purification of air and water • Detoxification and decomposition of wastes • Regulation of climate • Regeneration of soil fertility • Production and maintenance of biodiversity

46. Ecosystem services Key ingredients of our agricultural, pharmaceutical, and industrial enterprises

47. Ecosystem services We know that they are: • Essential to civilization

48. Ecosystem services We know that they are: • Essential to civilization • So complex that they can’t be replaced by technology (???)

49. Picture of biological machines

50. Ecosystem services We know that they are: • Essential to civilization • So complex that they can’t be replaced by technology (???) • Impaired by human activities