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Lakes and Ponds
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Formation of lakes Glacier lakes Oxbow lakes Playas Man-made lakes
Taal volcano lake Mitchigan lake Glacier lakes Oxbow lakes Playas Man-made lakes Grasmere lake Silver lake Lake lamonia
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How Does Glaciation Work?
Glaciers move they act as scouring pads 10,000 years ago, glaciers began to retreat Left behind large deposits of ice in hollows between hills which later melted to create lakes. The Seven Rila Lakes Rila, Bulgaria Lake Jokulsarlon, Iceland
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Glacier Lakes Carved out by glaciers (glaciation), which fill with water Northern U.S. and Canada
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The Great Lakes in northern U. S
The Great Lakes in northern U.S. are the largest glacial lakes in the world.
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Oxbow Lakes Formed by meandering rivers Loops of river gets cut off
Lakes are long and narrow, and usually U-shaped Common in low valleys and flat coastal areas
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Oxbow Lake An oxbow in the making: meanders and sandbank deposition on the Nowitna River, Alaska
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How Does an Oxbow Lake Form?
(1) On the inside of the loop, the river travels more slowly leading to deposition of silt.
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(2) Meanwhile water on the outside edges tends to flow faster, which erodes the banks making the meander even wider. (3) Over time the loop of the meander widens until the neck vanishes altogether.
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(4) Then the meander is removed from the river's current and the horseshoe shaped oxbow lake is formed. -- Without a current to move the water along, sediment builds up along the banks and fills in the lake.
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Oxbow Lake Oxbow lake and the Chippewa River in Eau Claire, Wisconsin.
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Playas Formed from multiple things that leave a depression
Sandhill cranes winter in playa lakes Playas Formed from multiple things that leave a depression Soil erosion, wind, animal herds Small, shallow, and circular Common in dry plains areas These lakes are ephemeral, and only form at certain times of the year
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Playas are important habitat for migratory birds and waterfowl.
The Red-winged Blackbird, Blue-winged Teal, and the Mallard can all be found in playa lakes at some time of the year.
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Playa lakes in Kansas agricultural area
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Man-Made Lakes Water reservoirs formed from Damming rivers
Old rock quarries or mines Stock ponds on farms and ranches Lake Mead is formed as a result of damming the Colorado River by the Hoover Dam in Nevada
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Zipingpu Dam on the Min River in China
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Natural Lakes in Texas *Largest designated natural lake Sabine Lake, Sabine and Neches rivers *Green Lake-10,000 acres is one of the state’s largest natural freshwater lakes *Caddo Lake, Texas-Louisiana border, was a natural lake originally, Natural Dam Lake *East Texas & Rio Grande in the lower valley small natural lakes formed by “horse-shoe” bends – aka ? *South Plains & West of San Angelo are lakes or "playas," such as Big Lake that are usually dry. 6,000 acres /11 hrs by heli
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Lake Baikal Crater Lake , Oregon
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Lentic Habitats Characterized by The shoreline The sides of the basin
The surface of the water The bottom sediments
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Zones of Lentic Habitats
Littoral zone Limnetic zone Profundal zone
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Littoral Zone Along shore where light can penetrate to the bottom
Rooted plants can grow Shores have coarse sediments from action of waves Sheltered areas have finer sediments (silt and clay) – plant growth in this zone Animal life includes Invertebrates common to lotic habitats Small fish
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Limnetic Zone Upper open water area of a pond or lake
Lack of rooted plants because light can’t penetrate the bottom Plankton and fish are common
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Profundal Zone Deep, bottom-water area No light penetration
No photosynthetic organisms or rooted plants Sediments are silt and clay mixed with organic matter that settles to the bottom Organisms living here are tolerant of little or no light or oxygen.
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Biological Productivity
The amount of plankton, algae, aquatic macroinvertebrates and fish that a body of water can produce and sustain Usually limited to the depth of light penetration Light penetration is limited by color of the water and amount of suspended solids ??? - Chlorophyll A & Water Clarity (turbidity)
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Ponds vs. Lakes Pond = body of water where light penetrates all the way to the bottom Lake = depth of light penetration varies from several inches to several feet
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Characteristics of Biological Productivity
4 categories of lake classification based on biological productivity Oligotrophic Mesotrophic Eutrophic hypereutrophic
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Oligotrophic Lakes Nutrient level and productivity is low
Water is clear Low aquatic plants and plankton Few fish Sandy bottoms with little organic material
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Mesotrophic Lakes Nutrients and productivity is moderate
Some aquatic plants Water clarity is becoming somewhat cloudy
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Littoral habitat in a mesotrophic lake
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Eutrophic Lakes Nutrient level and productivity is high
Large populations of algae, plankton, fish, plants, and macroinvertebrates Frequent plankton blooms Sediments with high organic matter Water is commonly colored
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Hypereutrophic Nutrient levels and productivity are very high
Large populations of aquatic plants and animals Frequent plankton blooms Sediments with most organic matter
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Ponds and Shallow Lakes
Temperature and dissolved oxygen remains about the same from top to bottom Water is easily mixed by the wind Photosynthesis and plant growth can occur from top to bottom (since light can penetrate all the way down)
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Deep Lakes Water temperature and dissolved oxygen levels can remain same from top to bottom layers in the winter During warm summer months, layers form The surface if warmed up by the sun Denser, colder water remains below it Doesn’t get mixed by the wind
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Mono Lake Dal Lake Okanagan Lake Lake Titicaca
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Fall Turnover
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Effects of Turnovers Mixing of once layered water returns oxygen levels to the deep areas. Areas in the south have one turnover per year in the fall. In the north, lakes become stratified in the summer and the winter (because ice forms on the surface, causing inverse stratification). Thus, there are two turnovers (fall and spring).
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https://youtu.be/_Ww6BIy3nc0?t=35s
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Zones of Stratification
Three distinct layers form in deep lakes during the summer months: Epilimnion Metalimnion Hypolimnion
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Epilimnion Warmest zone near the surface
Circulates freely with varying temperatures according to location on the globe Wind and currents mix surface water Most organisms found in this layer Area of greatest productivity Greatest light penetration Greatest oxygen content
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Metalimnion Middle layer
Steep declines in temperature (area of the thermocline) Temp. decreases 1oC per meter of depth
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Hypolimnion Third layer
Deep and cold with little to no temperature change Low oxygen due to few or no plants Little to no mixing by wind Bottom-dwelling organisms and bacteria feed on organic matter and further deplete the oxygen Little or no light penetration
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Ecological Succession
Lakes and ponds evolve differently then flowing water ecosystems. Over time, sediments become higher on the floor of ponds and lakes, and build up. The shallower the lake becomes, the further light can penetrate, so more plants grow on the bottom. Water tolerant plants and shrubs move in. Marshes, swamps, and bogs are usually the mature stage of a lake.
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A lake gradually fills with organic and inorganic sediments, shrinking the area of the pond
A bog forms, then a marshy area Finally, a meadow completes the succession stages
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Types of ponds Cypress Ponds Bog Ponds Meadow-Stream Ponds
Mountain Ponds Farm Ponds
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1. Cypress Ponds 2. Bog Ponds
Commonly found in the central or lower Mississippi Basin Waters are described as being brownish in color Many dry out during parts of the year. Willows, bay trees mixed with cypress trees, grow along the shore and are often found out in the waters. Cypress Pond ,Alabama 2. Bog Ponds found in the moist temperature regions of North America. Water is highly acidic and often muddy. Alders and cedar trees dominate Floating-leaf plants usually cover the surface.
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3. Meadow-Stream Ponds 4. Mountain Ponds
Where streams widen and the speeds of its currents slow down tremendously. The shallow part of the pond usually has an abundance of pondweeds, cattails, stonewort's and other plants. Floating leafy plants on the surface of the water, such as lilies and water shields. 4. Mountain Ponds Formed by glaciers Bottoms range from being rocky, graveled or muddy. ice in them and they usually dry up at some point during the summer. variety of animals and plants live in these icy waters.
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5. Farm Ponds Man-made ponds built to help keep the farmlands fertile.
spillway to control the water level. Farm ponds usually become abundant in fish, and are usually good waters for swimming and boating. fill from seepage, not from another stream which would fill the basin of the pond with silt and eventually kill the pond.
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Animals in Lakes and Ponds
Bitterling Bullfrog Green and Gold Bell Frog Common Carp Largemouth Bass Great Crested Grebe Great White Pelican Zambesi Softshell Platypus Lake Trout
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