Cycling of Matter in Ecosystems


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Cycling of Matter in Ecosystems

  1. 1. Cycling of Matter in ecosystems
  2. 2. Biogeochemical Cycles <ul><li>Recall: The particles that make up matter cannot be created or destroyed . </li></ul><ul><li>This means that all water and nutrients must be produced or obtained from chemicals that already exist in the environment. </li></ul>
  3. 3. <ul><li>This happens in a series of cycles in which chemicals are continuously consumed , rearranged , stored and used. </li></ul><ul><li>Because these cycles involve living (bio) organisms and occur on Earth (geo), they are called biogeochemical cycles . </li></ul>Biogeochemical Cycles
  4. 4. <ul><li>Every particle in every organism is part of a biogeochemical cycle! </li></ul>Biogeochemical Cycles
  5. 5. <ul><li>Water cycle = the series of processes that cycles water through the environment </li></ul><ul><li>Most of the water that is present in the water cycle is found in the abiotic environment. </li></ul>The Water Cycle
  6. 7. <ul><li>Carbon moves between the abiotic and biotic parts of an ecosystem in the carbon cycle. </li></ul><ul><li>Most of this exchange occurs between carbon dioxide (either in the atmosphere or dissolved in water) and photosynthesizing plants and micro organisms. </li></ul>The Carbon Cycle
  7. 9. <ul><li>While large quantities of carbon cycle through photosynthesis and cellular respiration , most of Earth’s carbon is not cycled. </li></ul>Carbon Deposits
  8. 10. Carbon Deposits <ul><li>Instead, it is stored in carbon-rich deposits such as fossil fuels (coal, oil, natural gas etc.) that form when decomposed organisms are compressed over millions of years. </li></ul>
  9. 11. <ul><li>Carbon is also stored for millions of years as limestone formed from dead marine organisms. </li></ul>
  10. 12. <ul><li>Large quantities of carbon are also contained in plant tissue and as dissolved carbon dioxide in the world’s oceans . </li></ul>Carbon Deposits
  11. 13. <ul><li>These locations are referred to as carbon sinks because carbon can enter or leave them over relatively short periods of time. </li></ul>Carbon Deposits
  12. 14. <ul><li>Human activities have a dramatic impact on the carbon cycle. </li></ul><ul><li>By burning fossil fuels , humans release the stored carbon into the atmosphere, which is contributing to global climate change . </li></ul>Human Impact
  13. 15. <ul><li>Deforestation also increases the concentration of carbon dioxide in the atmosphere. </li></ul>
  14. 16. <ul><li>Nitrogen is extremely abundant in the atmosphere , however it is not easy to acquire directly from the abiotic environment. </li></ul>Nitrogen Cycle
  15. 17. <ul><li>Nitrogen enters and leaves the atmosphere through a complex biochemical pathway called the nitrogen cycle . </li></ul>Nitrogen Cycle
  16. 18. <ul><li>Most of the nitrogen used by living things is taken from the atmosphere by certain bacteria in a process called nitrogen fixation . </li></ul>Nitrogen Cycle
  17. 19. <ul><li>These micro-organisms convert nitrogen gas into a variety of nitrogen-containing compounds, including nitrates , nitrites and ammonia . </li></ul>Nitrogen Cycle
  18. 20. <ul><li>Lightning and UV light also fix small amounts of nitrogen. </li></ul>
  19. 21. <ul><li>In addition, humans add nitrogen to the soil as fertilizer . </li></ul>Nitrogen Cycle
  20. 22. <ul><li>Once in the soil ecosystem, the nitrogen-rich compounds are available to producers . </li></ul><ul><li>After the nitrogen is absorbed, it is passed from producer to consumer and moves up the food chain. </li></ul>Nitrogen Cycle
  21. 23. <ul><li>Many animals consume more nitrogen than they can use, and excrete the excess in the form of urea or ammonia . </li></ul>Nitrogen Cycle
  22. 24. <ul><li>A dead organism’s nitrogen-rich compounds are taken in by decomposers , or are released back into the environment. </li></ul>
  23. 25. <ul><li>These compounds are either recycled again by soil micro-organisms, or they are converted by denitrifying bacteria back into nitrogen gas which then re-enters the atmosphere . </li></ul>Nitrogen Cycle