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Lake Succession

Lake Succession. Change in Lakes. Lakes not static - always changing Change is not random, but directional. Change in Lakes. In general, lakes proceed from a stage in which productivity is low, to a stage of high productivity. Change in Lakes.

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Lake Succession

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  1. Lake Succession

  2. Change in Lakes • Lakes not static - always changing • Change is not random, but directional

  3. Change in Lakes • In general, lakes proceed from a stage in which productivity is low, to a stage of high productivity

  4. Change in Lakes • Concurrent with change in productivity, the lake gradually fills in with organic matter and inorganic sediments

  5. Change in Lakes • Filling in and increasing productivity together produce lake aging or eutrophication • Gradual process that takes 100s or 1000s of years

  6. The Process • Start with a newly formed lake - glaciated region • Oligotrophic - low productivity - severely limited by cold climate

  7. The Process • Leeching from basin, runoff from watershed carries low amount of nutrients • Produces low productivity, primarily from phytoplankton

  8. The Process • Low productivity maintained by continued low inputs of inorganic nutrients from outside basin • Low productivity -> low levels of organic matter -> low rates of decomposition

  9. The Process • High dissolved O2 in hypolimnion results in low release of nutrients from sediments

  10. Low Productivity Cycle“Oligotrophic”

  11. Medium Productivity Cycle“Mesotrophic” Med. Med. Med. Med. Med. Med. Med. Med. Med.

  12. High Productivity Cycle“Eutrophic” High High High High High High High High Low

  13. Early Succession • High O2 • Low CO2 • Inorganic soil • Sparse vegetation • Sparse food (chiefly pelagic) • High transparency • Low fertility • Usually alkaline • “Coldwater” fishes

  14. Late Succession • Low O2 • High CO2 • Organic soil • Abundant vegetation • Abundant food • Low transparency • High fertility • Increasing acidity • “Warmwater” fishes

  15. Human-caused Lake Aging • Cultural eutrophication • Slow turnover • Accumulation of nutrients, excessive plant growth, algae blooms

  16. Case Study: The Great Lakes

  17. Littoral Encroachment

  18. Littoral Encroachment

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