Major Morphometric Characters Determining Aquatic Biology

Fall 1998 Lecture 2

  1. Major types of bodies of water - How to distinguish? What is Lake Valentine
  1. Lotic - Flowing waters - usually streams
  1. Estuaries - Brackish coastal waters where salt and fresh water mix in a distinct basin (bays or river mouth)
  2. Lentic - Standing waters
  1. Lakes - large bodies of standing water occupying a distinctive BASIN, that is mixed by wind
  1. Ponds - small quiet body of water usually shallow enough to permit the growth of rooted plants from shore to shore, largely mixed by convection
  2. Swamps - wet lowlands which support mosses and shrubs and large trees (cypress, mangroves, cottonwoods?)
  3. Marshes - broad treeless wetland areas with emergent macrophytes, grasses rushes & sedges

Bogs - sphagnum dominated, species poor, acidic filled only by rainwater

Fens - Species rich basins filled by mineral rich alkaline ground water

  1. Geomorphology of lake basins - How was Lake Valentine Formed and why is that important?

A. Why important?

  1. Determines watershed parameters - hydraulic residence time, retention time (nutrients), -
  1. Thermal Properties - stratification, light penetration
  2. Productivity is influenced

a. sediment - water interactions

b. littoral vs pelagic productivity

  1. Types of Lake Basins - Hutchinson recognized that most lakes in an area have a common formation and thus share features in common(called Lake Districts) (What might be the implications of this??) and went on to recognize 76 kinds of lake basins based upon the 3 major processes by which lakes are formed: Tectonic, Volcanic, & Glacial=80%
  1. Tectonic Basins — Lake basins formed by the folding, faulting, or movement of the earth's crust (bedrock)

-Hutchinson recognized 9 different types

a. single geologic fault - uplifting &/or subsidence

fault line

tilted fault blocks

= scarp lakes, deep lakes with one steep side (Albert Lake, OR)

b. double faults - trough lakes with steep and deep sides, rectangular, sharp shorelines, and low productivity

Graben Lakes (grave)

Examples: Lake Tahoe, Pyramid Lake Nevada Z = 313m, Zm = 50m

Lake Baikal - Siberia (Z = 730m, Zm = 1741

Lake Tanganyika - East Africa (Z = 557, Zm = 1435

Arms of Clear Lake , CA (Z = V/Ao, Zm = )

  1. Cryptodepression - faults at ocean side - small often saline lakes

Due to uplifting and isolation of a coastal "lake".

1964 AK earthquake

ocean

  1. Earthquake action - local subsidence - relatively shallow sharp sided lakes

Reelfoot Lake, TN in 1811-1813, the Mississippi flooded forming this lake.

  1. Uplifting around th e edge of a basin - Lake Bonneville - Great Salt Lake today ; the drainage basin becomes blocked and water evaporates leaving behind the dissolved salts increasing salinity.
  2. Regional uplifting (=epeirogenesis (p.13 Cole ) vs more rapid orogony or mountain building. Pleocene sea and Lake Okeechobee, FL Zm = 4m, Pleocene uplift to form the Florida Peninsula
  3. Sinkholes andBlowouts = the only two Geologically formed lake types in MN
  1. Volcanic Lakes - 10 types (How can volcanic activity form lakes?)
  1. Explosive origin lakes - Maars - small, circular, deep lakes > 100m, and <2km diameter
  2. Subsidence (internal collapse after lava is gone) - Caldera, When Mt Mazma collapsed in Oregon, Crater Lake was formed, which is the deepest lake in the US and the 7th deepest in the World (64 km2, Zm=610m, l = 10km. These are deep circular lakes with a much decreased DL , steep sides, and are mostly filled by precipitation/snow melt.

True crater lakes are rare!

  1. Lava Flow Lakes

Dams, repressions, overflow etc. e.g. Lake Taho is a tectonic basin that was blocked by a lava flow to form an outflow rim. Usually these are shallow productivelakes. Yellowstone Lake was formed from a collapsed lava flow.

  1. Glaciation - the major force creating most lakes in the N. Hemisphere (19 types according to Hutchinson) Most were formed during waves of glaciation in the Pleistocene 400,000 to 10,000 years ago.
  1. Alpine Glaciation

cirque lakes - one type of ice scour lake (Iceberg Lake, Glacial National Park, MT)

paternoster lakes - are chains of such lakes in a glacial valley

Are mostly small shallow (<50m), low T, low Productivity lakes, often with a bluegreen tinge due to the presence of fine glacial sediments in the water.

  1. Continental Glaciation, was formed by an end moraine on the south and west sides
  1. Terminal and lateral moraines - the accumulation of glacial debris

Lake Mille Lacs

  1. Depressions caused by weight of the ice sheet

Examples:

Lake Agassiz (now extinct) covered large areas of ND, MN, and Canada, and ice sheets to the north blocked the traditional northward flow of waters leading to today's modern numerous smaller lakes (Lake Winnipeg and Lake of the Woods, and the Red River Valley.

Great Lakes are remnants of ice scour lakes

Lake Mendota WI was formed by a lateral moraine damming a pre-glacial valley.

  1. Kettle lakes - were formed when ice blocks settled into drift and often took 50 to 200 years to melt. These are shallow (,50m), highly productive, somewhat steep sided lakes and is the origin of most lakes in MN, WI and central Canada
  1. Solution Lakes

Limestone or other salt based substrate is slowly dissolved out by "acid rain" leaving circular, conical shaped sinks. These typically are deep circular often unproductive lakes (Montezuma's Well, in central AZ)

Dolines (sinkholes) are the most common

  1. Wind Formed Lakes = erosively formed "deflation basins" (MN and MI dunes)
  1. Stream Action often forms lakes

a. Oxbow lakes formed by meander of rivers

b. Fluvatile or Riverine lakes formed by debri accumlation in a river

Where the Chippewa River in WI joins the Mississippi, Lake Pepin has been formed

c. Lateral Lakes

d. Plunge basins - formed by a waterfall (Dry Falls, Grand Coulee)

  1. Meteoritic (ET) lakes are often called astroblemes - Meteor crater in Flagstaff, AZ
  2. Organic - beaver dams
  3. Unknown - the Carolina Bays -
  4. Man made lakes - dams, farm ponds, reservoirs, old tires

Major Lake Morphometric Parameters:

Maximum length = Fetch (l)

Maximum Breadth.

Area

Volume

Zm = max depth

Z bar = V/A0

Zr = relative depth

Shoreline (L = perimeter)

Shoreline Development