LAKES AND PONDS
ECOSYSTEM
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.
Ponds and Lakes
May have limited species diversity
they are often isolated from one
another and from other water
sources like rivers and oceans.
Most ponds and lakes have outlet
streams and both are generally
temporary features on the landscape
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.
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.
As a glacier retreats, it may leave
behind an uneven surface containing
hollows that fill with water.
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.
Lake Baikal
Crater Lake , Oregon
Ponds and Lakes
Temperature varies seasonally.
During summer the temp. is from
4°C near the bottom to 22°C at the
top.
During winter the temp. is from 4° C
while the top is 0° 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 4° C.
Ponds and Lakes
divided into four different
“zones” determined by depth and
distance from the shoreline
• littoral zone
• limnetic zone
• profundal zone
• Photic zone
• Benthic zone
Littoral
Zone
Photic
Zone
Benthic
Zone
Limnetic
Zone
Profundal
(aphotic)
zone
Littoral Zone
warmest since it is shallow and can absorb
more of the Sun’s heat
sustains a fairly diverse community
several species of algae (like diatoms)
rooted and floating aquatic plants
grazing snails
Clams
Insects
Crustaceans
Fishes
amphibians
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
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 – most life
would not be possible without them
variety of freshwater fish also occupy this
zone
Profundal Zone
much colder and denser
little light penetrates all the way
through the limnetic zone into the
profundal zone
Plankton have short life spans—when
they die, they fall into the deepwater part of the lake/pond
Animals found are decomposers
Photic zone
Primary production in the photic zone is influenced by
three major factors
Nutrients
Light- For photosynthesis
Grazing pressure-the rate at which the plants are
eaten by herbivores.
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.
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.
LAKES
ECOSYSTEM
Clasification 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.
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.
Oligotrophic lake
Eutrophic Lake
Examples of lakes
Taal volcano lake
Mitchigan lake
Silver lake
Grasmere lake
Lake lamonia
Layers of lake separated by density gradient.
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.
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.
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
4°C throughout the year. The hypolimnion may
be much warmer in lakes at warmer latitudes.
BLUE LAKE
Dal Lake
Okanagan Lake
Mono Lake
Lac Pavin in France is a meromictic crater lake
Lake Hoare
Freshwater: biological communities of
lakes
PONDS
ECOSYSTEM
Ponds Ecosystem
A pond is a small, shallow body of fresh,
standing water in which relatively calm
water and extensive plant growth.
The amount of dissolved oxygen may vary
greatly during a day. In really cold places, the
entire pond can freeze solid.
Water temperature is fairly even from top to
bottom and changes with air temperature.
Types of ponds
Cypress Ponds
Bog Ponds
Meadow-Stream Ponds
Mountain Ponds
Farm Ponds
1. Cypress 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 on the Conecuh River near River Falls, Alabama
2. Bog Ponds
Bog Ponds are often 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.
3. Meadow-Stream 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, stoneworts 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.
Most of the time Mountain Ponds have ice
in them and they usually dry up at some
point during the summer.
Sedges grow along its margins. In spite of
the pond’s short summer season, a variety
of animals and plants live in these icy
waters.
5. Farm Ponds
Man-made ponds built to help keep the
farmlands fertile.
It should also have a spillway to control
the water level.
Farm ponds usually become abundant in
fish, and are usually good waters for
swimming and boating.
They should also fill from seepage, not
from another stream which would fill the
basin of the pond with silt and eventually
kill the pond.
Examples of ponds
VEGETATION IN LAKES AND PONDS
ECOSYSTEM
Animals in Lakes and Ponds
Bitterling
Bullfrog
Common Carp
Green and Gold
Bell Frog
Largemouth Bass
Great Crested Grebe
Great White Pelican
Lake Trout
Platypus
Zambesi Softshell
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 and earth is mostly
covered with water, so the temperature of the atmosphere
is kept fairly constant and able to support life.
Plankton which account for most of the photosynthesis on
Earth found in lakes, ponds and oceans. Without, there
might not be enough oxygen to support such a large world
population and complex animal life.
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.
Environmental Problems:
Freshwater biomes have suffered mainly from
pollution.
Runoff containing fertilizer and other wastes,
and industrial dumpings enter into rivers,
ponds, and lakes tend to promote abnormally
rapid algae growth- ARTIFICAIL
EUTROPHICATION
When algae die, dead organic matter ends up
in the water. This makes the water unusable,
and it kills many of the organisms living in the
habitat.
Possible Solution:
Pond Aeration
To restore a pond or lake to a healthy condition,
we must restore the natural processes that
allow them to assimilate the nutrient load that it
receives.
Ideally, nutrient inputs should be reduced or
eliminated wherever possible. Only use
phosphorus-free fertilizers on lawns.
Preventing nutrients from flowing down storm
sewers is a good way to prevent pollution.
THE END……