LAKE ECOLOGY

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

Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part 3-s2

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.

Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part 3-s3

Modules 2/3 outline

1. Introduction2. Major groups of organisms; metabolism3. Basins and morphometry4. Spatial and temporal variability – basic

physical and chemical patchiness (habitats)5. Major ions and nutrients 6. Management – eutrophication and water

quality

Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part 3-s4

3. Lake basins & morphometry

Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part 3-s5

Lake types and classifications

Insert ~ 4 photos of various pond, lake, and reservoirs

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

Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part 3-s6

Major Lake Types

Major types: glacial tectonic volcanic reservoirs solution landslide oxbow

Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part 3-s7

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

Glacial lake basins

Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part 3-s8

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)

Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part 3-s9

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)

Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part 3-s10

Slow uplifting of ancient sea beds to form shallow depressions

L. Okeechobee, FL

Tectonic Basins – Uplifted sea beds

Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part 3-s11

Images of uplifted sea beds

•L. Titicaca, Bolivia-Peru•Great Salt Lake

More uplifted ancient seabeds

Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part 3-s12

•http://geopubs.wr.usgs.gov/fact-sheet/fs092-02/

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

•www.cs.uoregon.edu/.../oregon/large/

Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part 3-s13

Other lake types

Reservoirs – What’s 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/

Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part 3-s14

Landslide formed

Oxbow lakes –

the river changed course

                            

  

And more lake types

Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part 3-s15

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

Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part 3-s16

WOW Minnesota Lakes

Wow lake images

ShagawaMedicine

Independence

Ice Lake

•Lake Independence

Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part 3-s17

Lake Minnetonka

Formed by glacial melting during the last Ice Age

16 interconnected lakes; ~23 named bays and areas

Halsteds Bay

West Upper Basin

Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part 3-s18

Washington Onondaga

Mead - Las Vegas Bay Boulder Basin - Sentinel I.

WOW Lakes

Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part 3-s19