Limnology lentic lakes and ponds lotic streams and rivers

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Limnology(lentic lakes and ponds lotic
streams and rivers)

• Properties of Lakes
• Origins
• Water Balance
• Light
• Heat and Stratification
• Oxygen
• Nutrients Nitrogen and Phosphorous

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Origins of lakes

• Tectonic
• Volcanic
• Landslides
• Glacial action
• Solution of rock
• River activity
• Shoreline activity
• Biological (beavers)
• Human

Spirit Lake
Glacier Bay
Bonneville Reservoir
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The distribution of reservoirs
Distribution of reservoirs over 500 acres in the
United States, by surface area, January 1970.
One dot equals 10,000 acres. Total area, 90
million acres (Jenkins, R.M. 1970. AFS Spec.
Publ. No. 7).
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Limnology water balance

• Water inputs
• Precipitation, surface runoff from basin,
  groundwater, diversion
• Water losses
• Drainage, seepage, evaporation and
  evapo-transpiration (plants), diversion

Soap Lake, WA
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Global water supply
Adapted from Wetzel 1975
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Limnology light
Clear, relatively unproductive lake
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Absorbance of different colors of light on a log
scale in a clear unproductive lake. Note the
rapid loss in the quantity, and change in the
quality of light. Pattern vary among lakes,
depending on the nature of material in the water
such as glacial flour, tannin, phytoplankton, etc.
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15 10 5 0
10
0.1 1.0 10 100
Limnology 1994
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Heating and cooling

• Sources of heat
• Direct solar radiation (most important)
• Groundwater and springs
• Ground (minor)
• Losses of heat
• Thermal radiation (primary)
• Conduction
• Evaporation
• Outflow

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Heat and the density of water
The maximum density of water is at 3.94 C. Ice
at 0 C is 8.5 lighter than liquid water at 0,
so it floats. Above 3.94 water gets lighter as
it warms up, so the surface water is also warmer
than deep water in summer.
x
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Distribution of heat

• Horizontal distribution is primarily driven by
  wind
• Vertical stratification is seasonal, driven by
  the relationship between density and temperature

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Limnology heat
Dimictic Lake (turns over twice a year)
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Limnology heat
Monomictic lake (turns over once each year)

Depth (m)
Time (month)
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Limnology heat

• The distribution of heat within a lake depends on
  water movement
• Surface waves
• Langmuir circulation waves
• River Influents

Clear Lake, California
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Dissolved Oxygen
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Dissolved Oxygen

• Air contains 300 mg O2/L the rest is mostly
  nitrogen
• Water contains 14.6 mg O2/L
• Gasses diffuse slowly in water, so distribution
  is governed by circulation, not diffusion
• Eutrophic Lakes hypolimnion depleted by
  decomposition (biotic processes)
• Oligotrophic Lakes
• Distribution governed by physical processes

In warm water, the metabolic demands of fishes
tend to increase, and the capacity of the water
to hold oxygen decreases.
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Dissolved Oxygen

• Winter Kill
• Occurs when a shallow lake is ice-covered and
  hence dark for a long period. The DO demand of
  plants can drive levels below the 2 mg/l required
  by most fish.
• Summer Kill
• Occurs when dense concentrations of macrophytes
  die at the end of their growing season.
  Decomposition can drive DO levels down. If the
  lake is shallow and macrophytes are found over
  the whole surface, a squeeze between warm
  surface temperatures and low DO levels on the
  bottom in late summer can kill fish.

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Relationship between dissolved oxygen level and
depth below the ice in Black Lake, Alaska.
G. Ruggerone
0 50 100 150
Oxygen ( of saturation)
8 mg/l is needed to maintain healthy salmon
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Survival of juvenile sockeye salmon in Black Lake
at different dissolved oxygen concentrations
(Ruggerone 1999)
Percent survival
0 20 40 60 80 100
0 25 50 75 100
Oxygen ( saturation)
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Development of temperature dissolved oxygen
squeeze from summer-kill conditions in Lake
Sammamish
Data Hans Berge, Metro King County
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Limnology Nitrogen and Phosphorous
Nitrogen and Phosphorous are essential elements
for living organisms, and one, the other, or both
in concert may limit primary and secondary
production. In lakes, nitrogen comes primarily
from microbial action or terrestrial runoff and
phosphorous primarily from local geology.
However, both can be greatly affected by human
inputs.
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Primary and secondary production may be limited
by Nitrogen or Phosphorus
Fish biomass (kg/ha)
Fish biomass (kg/ha)
Total phosphorous
Macro-benthos biomass
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Natural and human sources for Nitrogen and
Phosphorous
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The problem So many lakes, so little time (and
money). How can we get a conceptual basis for
understanding how lakes function and also help
fishery managers estimate the potential of lakes
to yield fish? The solution A morphoedaphic
index

• Objectives
• Determine empirical relationships of fish yield
  with abiotic factors
• Provide fisheries managers with an easily applied
  technique for first approximation of annual fish
  yield.
• Provide a fundamental conceptual base for the
  global synthesis for production process in
  aquatic systems.

R.A. Ryder. 1982. Trans. Amer. Fish. Soc. 111
154-164.
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Morphoedaphic Index
Ryder 1982, TAFS 111154-164
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Morphoedaphic Index
Morphoedaphic Index N/z N nutrient value
(total dissolved solids TDS) z mean depth (m)
The lake is considered to be a black box, and
multiple, complex interaction are disregarded
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Broad-scale relationship between the
Morphoedaphic Index and the long-term yield of
fishes from lakes
Schlesinger and Regier 1982 TAFS
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The Morphoedaphic Index needs to be adjusted for
regional climate conditions
Yield (kg/ha/year)
1 10 100
1 10 100
Morphoedaphic Index
1982 Adapted from TAFS 111 141-150
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Morphoedaphic Index
Isolines showing theoretical upper limits to
maximum sustainable fish yield (kg/hectare/year)
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Limnology light
http//www.ucar.edu/learn/images/spectrum.gif
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Limnology light
Shallow, productive reservoir
Clear, relatively unproductive lake
0
5
15 10 5 0
10
0.1 1.0 10 100
Absorbance of different colors of light on a log
scale by a clear unproductive lake and a highly
productive, shallow reservoir.
0.1 1.0 10 100
Limnology 1994
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Limnology Nitrogen and Phosphorous
Simplified Nitrogen cycle