LAKE ECOLOGY

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LAKE ECOLOGY

• Unit 1 Module 2/3 Part 3 Basins and
  Morphometry January 2004

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Modules 2/3 overview

• Goal Provide a practical introduction to
  limnology
• Time required Two weeks of lecture (6 lectures)
  and 2 laboratories
• Extensions Additional material could be used to
  expand to 3 weeks. We realize that there are far
  more slides than can possibly be used in two
  weeks and some topics are covered in more depth
  than others. Teachers are expected to view them
  all and use what best suits their purposes.

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Modules 2/3 outline

1. Introduction
2. Major groups of organisms metabolism
3. Basins and morphometry
4. Spatial and temporal variability basic physical
   and chemical patchiness (habitats)
5. Major ions and nutrients
6. Management eutrophication and water quality

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3. Lake basins morphometry
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Lake types and classifications

• Lakes are open bodies of slow moving water not in
  contact with the ocean
• Lake origin and geology determine
• Basin area, shape, depth
• Watershed size and mineral soils
• Basic water quality and sediment characteristics

Insert 4 photos of various pond, lake, and
reservoirs
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Major Lake Types

• Major types
• glacial
• tectonic
• volcanic
• reservoirs
• solution
• landslide
• oxbow

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Glacial lake basins

• Most recent 14,000 b.p.
• ice scour lakes
• morainal lakes
• ice block/kettle lakes
• Includes most of the lakes in the Upper Great
  Lakes and New England region

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Lots of beautiful glacial lake basins out there

• Castle Lake, CA cirque lake formed by glacier
  scour leaving a terminal moraine at the outflow
  and a lateral moraine than separates a 5m deep
  littoral plain from a 35 m deep bowl
• Typically have low watershed to lake area ratio
  (Aw A0)

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Tectonic lake basins Graben-Rift

• Faults and depressions created from crustal
  movements
• The deepest lakes in the world were formed from
  parallel fault blocks that sank to create
  flat-bottomed grabens (Tahoe, Baikal, Tanganyika)

Lake Tahoe, CA-NV (tahoe.usgs.gov)
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Tectonic Basins Uplifted sea beds

• Slow uplifting of ancient sea beds to form
  shallow depressions

L. Okeechobee, FL
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More uplifted ancient seabeds

• Images of uplifted sea beds

• Great Salt Lake

• L. Titicaca, Bolivia-Peru

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Volcanic Caldera Lakes

• Crater Lake- 589 m deep (Mt. Mazama exploded)
• Very low watershed to lake area ratio (Aw A0)

• Steep sides
• Low nutrient soils
• Unproductive
• Extremely clear

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Other lake types

• Reservoirs Whats that dammed lake for ?
• usually created for multiple uses and so result
  in multiple conflicts

• Solution lakes formed by the dissolution of
  limestone deposits
• Are sinkholes in Florida prime lakeshore real
  estate ?
• Areas with numerous solution lakes are known as
  Karst topography

USBR http//www.hooverdam.usbr.gov/
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And more lake types
Landslide formed

Oxbow lakes the river changed course
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The WOW lakes

• Shagawa L., MN - glacial
• L. Minnetonka - glacial
• Medicine L., MN glacial
• Independence, MN - glacial
• Ice L., MN - glacial
• Grindstone L., MN - glacial
• L. Onondaga, NY morainal
• L. Washington, WA fjord lake
• L. Mead, NV/AZ - reservoir

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WOW Minnesota Lakes

• Wow lake images

Shagawa
Medicine
Ice Lake
Independence

• Lake Independence

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Lake Minnetonka

• Formed by glacial melting during the last Ice Age
  
• 16 interconnected lakes 23 named bays and
  areas

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WOW Lakes
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