2. Ponds and Lakes
Range in size from just a few square
meters to thousands of square
kilometers.
Ponds may be seasonal, lasting just a
couple of months (such as sessile
pools).
Lakes may exist for hundreds of
years or more.
3. Ponds and Lakes
May have limited species
diversity
Most ponds and lakes have
outlet streams and both are
generally temporary features
on the landscape
4. Formation of Lakes and Ponds:
Some of the oldest lakes and ponds
(more than three hundred thousand
years old) were formed by tectonic
activity related to movement of Earth's
crust.
EXAMPLE: Lake Baikal in Siberia formed
from the movement of tectonic plates and
is the largest freshwater lake by volume
in the world.
5. Formation of Lakes and Ponds:
Lakes and ponds are formed through
a variety of events, including glacial,
tectonic, and volcanic activity.
Most lakes and ponds form as a
result of glacial processes.
6. Formation of Lakes and Ponds:
Volcanic activity can also lead to lake and
pond formation.
EXAMPLE: the collapse of a volcanic cone
of Mount Mazama in Oregon led to the
formation of Crater Lake, the seventh
deepest lake in the world.
8. Ponds and Lakes
Temperature varies seasonally.
During summer the temp. is from
4ยฐC near the bottom to 22ยฐC at the
top.
During winter the temp. is from 4ยฐ C
while the top is 0ยฐ C (ice).
during the spring and fall seasons is
a mixing of the top and bottom
layers resulting in a uniform water
temperature of around 4ยฐ C.
9.
10. Ponds and Lakes
divided into four different
โzonesโ determined by depth and
distance from the shoreline
โข littoral zone
โข limnetic zone
โข profundal zone
โข Photic zone
โข Benthic zone
12. Littoral Zone
warmest since it is shallow and can absorb
more of the Sunโs heat
sustains a fairly diverse community
several species of algae (like diatoms)
rooted and floating aquatic plants
grazing snails
Clams
Insects
Crustaceans
Fishes
amphibians
13. Littoral Zone
the egg and larvae stages of some insects are
found in this zone
vegetation and animals living in the littoral
zone are food for other creatures such as
turtles, snakes, and ducks
14. Limnetic Zone
near-surface open water surrounded by
the littoral zone
well-lighted (like the littoral zone) and is
dominated by plankton, both
phytoplankton and zooplankton
plankton are small organisms that play a
crucial role in the food chain โ most life
would not be possible without them
variety of freshwater fish also occupy this
zone
15. Profundal Zone
much colder and denser
little light penetrates all the way
through the limnetic zone into the
profundal zone
Plankton have short life spansโwhen
they die, they fall into the deep-
water part of the lake/pond
Animals found are decomposers
16. Photic zone
Primary production in the photic zone is influenced by
three major factors
Nutrients โ oxygen, phosphorus, carbon
Light- For photosynthesis
Grazing pressure-the rate at which the plants are
eaten by herbivores.
17. Photic zone
Nutrients, especially phosphate and nitrate, are often
scarce in the photic zone because they are used up
quickly by plants during photosynthesis.
External inputs of nutrients are received through:
Rainfall
Riverflow
Weathering of rocks and soil
Human activities- sewage dumping.
18. Benthic Zone
The area of the bottom.
Many groups and varieties of animals live here, a few
are worms, crustaceans, and protozoa.
The life in this zone is mostly made up of bottom
dwellers which get most of their food from dead and
decaying organisms.
most of the organisms in the benthic zone are
scavengers because they depend on dead flesh as
their main food source.
20. Classification of Lake
Oligotrophic lakes- deep, nutrient-poor lakes
in which the phytoplankton is not very
productive.
The water is usually clear
Eutrophic lakes- shallow, nutrient-rich lakes
with very productive phytoplankton.
The waters are usually murky due to large
phytoplankton populations
the large amounts of matter being
decomposed may result in oxygen depletion.
21. Lakes Ecosystem
A lake is bigger than a pond, and is too deep to
support rooted plants except near the shore.
Some lakes are big enough for waves to be
produced.
Lakes may exist for hundreds of years or more.
Lakes are often classified as oligotrophic or
eutrophic, depending on the amount of organic
matter produced.
25. 1. Epilimnion
the top-most layer in a thermally
stratified lake.
It is warmer and typically has a
higher pH and dissolved oxygen
concentration than the hypolimnion.
It typically mixed as a result of surface
wind-mixing.
Free to exchange dissolved gases (ie
O2 and CO2) with the atmosphere.
It contains the most phytoplankton.
26. 2. Thermocline
(sometimes metalimnion) is a thin but distinct
layer in a large body of fluid (e.g. water, such as an
ocean or lake, or air, such as an atmosphere).
Temperature changes more rapidly with depth than
it does in the layers above or below.
Thermoclines may be a semi-permanent feature of
the body of water in which they occur, or they may
form temporarily in response to phenomena such
as the radiative heating/cooling of surface water
during the day/night.
Factors that affect the depth and thickness of a
thermocline include seasonal weather variations,
latitude, and local environmental conditions, such
as tides and currents.
27. 3. Hypolimnion
The hypolimnion is the dense, bottom layer of
water in a thermally-stratified lake. It is the layer
that lies below the thermocline.
Typically the hypolimnion is the coldest layer of a
lake in summer, and the warmest layer during
winter. Being at depth, it is isolated from surface
wind-mixing during summer, and usually receives
insufficient irradiance (light) for photosynthesis to
occur.
In deep, temperate lakes, the bottom-most
waters of the hypolimnion are typically close to
4ยฐC throughout the year. The hypolimnion may
be much warmer in lakes at warmer latitudes.
34. Bitterling Bullfrog Common Carp
Great Crested Grebe
Great White Pelican
Green and Gold
Bell Frog
Lake Trout
Largemouth Bass
Animals in Lakes and Ponds
Platypus
Zambesi Softshell
35. Functions:
Lakes and ponds typically contain a diversity of organisms
that perform different ecological functions.
Lakes and ponds are an important source of fresh water for
human consumption
Water has a high capacity for heat.
Plankton which account for most of the photosynthesis on
Earth found in lakes, ponds and oceans.
We fish from the ponds and we often eat the fish we catch.
Most of the time our water comes from the lakes and
ponds, but purified.
36. Environmental Problems:
Freshwater biomes have suffered mainly from
pollution.
Runoff containing fertilizer and other wastes,
and industrial dumping's enter into rivers,
ponds, and lakes tend to promote abnormally
rapid algae growth- ARTIFICIAL
EUTROPHICATION
When algae die, dead organic matter ends up
in the water.
