Aquatic Ecology Notes

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Aquatic Ecology Notes
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Photic Zone
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Aphotic Zone
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Intertidal Zone
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Coral Reef
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Life in Layers

• Life in most aquatic systems is found in surface,
  middle, and bottom layers.
• Temperature, access to sunlight for
  photosynthesis, dissolved oxygen content,
  nutrient availability changes with depth.
• Euphotic zone (upper layer in deep water
  habitats) sunlight can penetrate.

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Lakes Water-Filled Depressions

• Lakes are large natural bodies of standing
  freshwater formed from precipitation, runoff, and
  groundwater seepage consisting of
• Littoral zone (near shore, shallow, with rooted
  plants).
• Limnetic zone (open, offshore area, sunlit).
• Profundal zone (deep, open water, too dark for
  photosynthesis).
• Benthic zone (bottom of lake, nourished by dead
  matter).

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Littoral Zone

• A shallow area near the shore, to the depth at
  which rooted plants stop growing. Ex. frogs,
  snails, insects, fish, cattails, and water lilies.

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Limnetic Zone

• Open, sunlit water that extends to the depth
  penetrated by sunlight.

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Profundal Zone

• Deep, open water where it is too dark for
  photosynthesis.

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Lakes Water-Filled Depressions
Figure 6-15
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Oligotrophic
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Eutrophic
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Freshwater Wetlands
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Freshwater Inland Wetlands Vital Sponges

• Inland wetlands act like natural sponges that
  absorb and store excess water from storms and
  provide a variety of wildlife habitats.

Figure 6-18
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Freshwater Inland Wetlands Vital Sponges

• Filter and degrade pollutants.
• Reduce flooding and erosion by absorbing slowly
  releasing overflows.
• Help replenish stream flows during dry periods.
• Help recharge ground aquifers.
• Provide economic resources and recreation.

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Marshes

• An area of temporarily flooded, often silty land
  beside a river or lake.

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Swamps

• A lowland region permanently covered with water.

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Importance of freshwater wetlands

• They filter purify water.
• Habitat for many animals and plants.

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Historical Aspects

• Developers and farmers want Congress to revise
  the definition of wetlands. This would make
  60-75 of all wetlands unavailable for
  protection. The Audubon Society estimates that
  wetlands provide water quality protection worth
  1.6 billion per year, and they say if wetlands
  are destroyed, the U.S. would spend 7.7 billion
  to 31 billion per year in additional
  flood-control costs.

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Estuaries
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Definition

• A partially enclosed area of coastal water where
  sea water mixes with freshwater.

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Salt Marshes

• The ground here is saturated with water and there
  is little oxygen, so decay takes place slowly.
  It has a surface inlet and outlet, and contains
  many invertebrates. It is also the breeding
  ground for many ocean animals. Ex. crabs and
  shellfish.

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Mangrove Forests

• These are along warm, tropical coasts where there
  is too much silt for coral reefs to grow. It is
  dominated by salt-tolerant trees called mangroves
  (55 different species exist). It also helps to
  protect the coastline from erosion and provides a
  breeding nursery for some 2000 species of fish,
  invertebrates, and plants.

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Importance of Estuaries

• Just one acre of estuary provides 75,000 worth
  of free waste treatment, and has a value of about
  83,000 when recreation and fish for food are
  included.
• Prime Kansas farmland has a top value of 1,200
  and an annual production value of 600.