Lake Succession and

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Lake Succession and
Eutrophication
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Some Definitions

• Geologic lake succession
• Eutrophication
• Cultural eutrophication

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Classical View of Lake Succession

• Oligotrophy
• Mesotrophy
• Eutrophy
• Dystrophy
• Extinction

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Figure 1 Trophic Status Of 5 Lakes
Goldman and Horne (1983)
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General progression depends on

• Original basin shape
• Mean depth
• Nature of drainage basin
• Erosion rates
• Soil composition ? nutrient inputs
• Hydrologic residence time
• Climate
• Rain and snowfall
• Mean temperature
• Atmospheric nutrient inputs
• Geologic age

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Figure 2 Factors for Lake Succession
G.E. Likens, ed., (1972). Symp. On Nut Eutro.
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The Eutrophication Paradigm

• Nutrient enrichment
• Natural
• Anthropogenic urban, industrial, agricultural
• Increased organic matter production
• Increased growth transfers up the food chain
• Gradual filling of basin
• Sedimentation
• Accumulation of slowly decomposing plants (peat)
  refractory compounds
• Terrestrial plant invasion

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Figure 3 Lake Succession
Whittaker (1970) Comm. Ecosystems
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Figure 4 Oxygen and Temperature vs. Trophic
Status
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General Characteristics of Lakes
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Developments in Eutrophication Concepts

• Oligotrophy is more mature than eutrophy
  (Margalef, 1968)
• High biotic diversity in oligotrophic lakes
• Long lasting steady-states in lake trophic status
  (Hutchinson, 1969 and 1973)
• Oligotrophic lakes can last for centuries without
  anthropogenic inputs, such as sewage

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Cultural Eutrophication

• Sources of nutrient enrichment
• Municipal sewage
• Industrial wastes
• Agricultural fertilizers
• Detergents (phosphorous)
• Sediment from land clearing, road building, land
  development
• Poor forest practices

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Examples of Cultural Eutrophication

• The Great Lakes
• Large population increases and forest clearing
• Point and non-point nutrient sources
• Volumes and retention times influence response
• Lake Erie (shallow) most rapid eutrophication
  and recovery
• Lake Ontario (deep) slow recovery due to
  internal loading
• Lake Michigan (large and deep) extreme local
  eutrophication
• Lake Superior (larger volume) slow response to
  nutrient loading

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Figure 5 Eutrophication in the Great Lakes as
Reflected in Total Dissolved Solids
Whittaker (1970) Comm. Ecosystems
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• Lake Washington
• Progressive eutrophication highly populated
  watershed
• Then recovery (? transparency, ? Chl-a) following
  sewage diversion
• W.T. Edmundson who organized local action groups
• Relatively rapid response short hydraulic
  residence time (little internal loading)
• Mostly a P issue, N levels remained high

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Figure 6 Lake Washington Recovery