Transcript LAKES and PONDS

Warm-up
1.
2.
3.
The 3 zones in a river are...
Identify one river zone and list 2
biological and 2 physical characteristics.
Identify one river zone and one species
of fish that survives best in that zone.
Explain why that species is adapted to
that zone.
LAKES and PONDS
Formation of Lakes – Great Lakes
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The Great Lakes did not exist in preglacial times but are the
cumulative result of several phases of glaciation that took
place during the last 1.5 million years.
Ice-marginal lakes (or proglacial lakes) form when the land in
front of the ice slopes toward the ice, allowing meltwater to
pond directly in contact with the ice, as shown below
Drainage continued southward to the Gulf
of Mexico.
The present-day Great Lakes formed as the earth’s crust,
depressed from the weight of the ice sheets, rebounded
after deglaciation.
Formation of Lakes - Volcanoes
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Crater Lake (Oregon) was formed after the
collapse of an ancient volcano, named Mount
Mazama.
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This volcano violently erupted approximately 7700
years ago. That eruption was 42 times as powerful
as the 1980 eruption of Mount St. Helens.
Lentic Ecosystems
Lakes differ from ponds on the depth and
amount of water.
 Plants and animals are distributed within
ponds and lakes according to depth of
water and distance from shore.
 Usually ponds will have sunlight reaching
the bottom all the way across the entire
body of water.
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ZONES of Lakes
Littoral zone- a shallow well lighted
area with warm water that is close to
shore and hosts emergent plants.
 This area is the most diverse with algae,
snails, insects, fish, amphibians, reptiles and
mammals.
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Sunlight
Painted
turtle
Blue-winged
teal
Green
frog
Muskrat
Pond
snail
Littoral zone
Plankton
Diving
beetle
Northern
pike
Yellow
perch
Bloodworms
Fig. 8-15, p. 175
Limnetic Zone
Well lighted area with open surface of
water farthest from the shore.
 Also known as the epilimnion.
 Occupied by plankton, fish and some
reptiles.

Littoral
zone
Plankton
Northern pike
Yellow
perch
Profundal zone
Also known as the hypolimnion.
 Deep aphotic region.

◦ Aphotic- no light penetration.
Littoral
zone
Plankton
Northern pike
Yellow
perch
Bloodworms
Benthic Zone
Bottom of aquatic ecosystems.
 Nutrients are delivered to this area in the
form of detritus.
 Detritus is the dead organic matter that
“rains” down from upper areas.
 Has many decomposers and also fish, clams,
mussels, etc.
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Lake and Pond Succession
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OLIGOTROPHIC - are generally clear, having
a low concentration of plant life. Typically
glacial lakes
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MESOTROPHIC - have good clarity and an
average level of nutrients.
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EUTROPHIC - are enriched with nutrients,
resulting in good plant growth and possible
algal blooms. Older ponds.
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Eutrophication - the speeding up of pond
succession due to fertilizer runoff from
agriculture.