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Energy flow through ecosystems

Energy flow through ecosystems. Only 5% of the solar energy that arrives on earth is captured by photosynthesis. The energy captured powers life. Trophic levels. Energy flow versus Biogeochemical cycles. A generalized biogeochemical cycle. Consumers. Producers. Decomposers.

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Energy flow through ecosystems

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

  2. Trophic levels

  3. Energy flow versus Biogeochemical cycles

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

  5. Carbon cycle Carbon is the conduit for energy flow!

  6. 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)

  7. 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

  8. Carbon cycle

  9. 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

  10. Carbon stocks Sedimentary rocks > deep oceans > atmosphere = organisms and soils

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

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

  13. 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

  14. 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

  15. Nitrogen cycle • N enters system through biological fixation

  16. Nitrogen accumulates over primary succession

  17. 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?

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

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

  20. 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

  21. 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

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

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

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

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

  26. Water balance in ecosystems Inputs = storage + outputs

  27. Water balance in ecosystems Soil is like a bucket

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

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

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

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

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

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

  34. Ecosystem services • Purify air and water water • Pollination of crops • Detoxify and decompose wastes • Stabilize climate • Ozone protection from UV • Maintain biodiversity • Control agricultural pests • Generate and preserve soil fertility • Maintain recreational areas

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

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

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

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

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