Environmental Science
Chapter 7 Lecture Notes
Aquatic Habitats
Targets: Freshwater Ecosystems
1. I can describe the 5 factors that determine
where an organism lives in an aquatic
ecosystem.
2. I can classify the 3 major groups of
organisms living in aquatic biomes.
3. I can name and describe the 3 major
groups of Illinois freshwater biomes.
4. I can identify and describe the 8 specific
types of freshwater biomes.
5. I can explain the differences between a
pond and a lake.
Aquatic Ecosystems
T1
• Mainly determined by water’s ____________
– Freshwater
– Marine
– Estuary
• Other abiotic factors that determine where
organisms are found in a body of water:
– ____________________
– ____________________
– ____________________
– ____________________
Classification of Aquatic Organisms
• 3 Major Groups:
•
– __________: microscopic;
float freely in water
• Heterotrophs =
________________
• Autotrophs =
________________
– ___________: swim
actively in open water
– __________: bottomdwelling; often attached to
hard surfaces
Decomposers
T2
THREE major groups of Illinois
Freshwater Habitats:
T3
• ____________
• ______________
• _____________________
Lakes and Ponds Video
T3
LAKES
• Non-free-flowing
•
•
bodies of water
6 or more acres in size
Large enough to have
wind-swept beaches
– Lake Michigan
– Carlyle Lake
– Rend Lake
↓
↓
T3
PONDS
• Non-free-flowing
•
•
bodies of water
Less than 6 acres in
size
Usually not large
enough for winds to
blow/create waves
that would wash
away plants trying to
take root
T5
PONDS
LAKES
________
________
________
________
Top and bottom
water generally
have the same
temperature
May have
dramatically
different
temperatures
from the surface
to bottom waters
_________ _________
Affected by local
climate
Affect local
climate if large
enough
RIVERS AND STREAMS
• Free-flowing deep
•
water habitats
Contained within a
______________
T3
Different Types of Lakes, Ponds,
Rivers and Streams
T4
1. Glacial Lakes
• Created 2 million
years ago
• Formed from
glaciers
• Great Lakes
(H.O.M.E.S.)
• Lake Zurich
2. Oxbow Lakes
T4
• Crescent-shaped lake next to winding
river
• Formed as erosion and soil deposits
____________________________
Formation of an Oxbow Lake
(1) On inside of loop, river travels
more slowly leading to deposits
of silt.
(2) Water on outside edges flows
faster, erodes banks making the
loop even wider.
(3) Over time the loop of the
meander widens until the neck
vanishes altogether.
(4) The meander is removed from
the river's current and the
horseshoe shaped oxbow lake is
formed.
Oxbow Lake Formation Video
T4
3. Impoundments / Reservoirs
• Formed by blocking
river with a ________
• Man-made
• Carlyle Lake formed by
damming water of
Kaskaskia River
• Often used for
_________________
in central and southern
Illinois
T4
4. Ponds/Storm-Water Detention
Basins
• Created by digging out or
expanding a lowland area
• _______________
T4
5. Perennial Streams /
Rivers
• Water flows through channel
____________________
• In Illinois, there is no legal distinction
between a river or perennial stream
T4
6. Intermittent Stream
• Water flows through a channel
__________________________
T4
7. Tributary
• Smaller stream/river
that
__________________
__________________
• Major tributaries of
Illinois River are the
Kankakee, Des Plaines,
Fox, Spoon, Sangamon
and Mackinaw Rivers
T4
Targets: Freshwater Ecosystems
6. I can name sources of water for freshwater
biomes and explain the importance of the
hydrologic cycle and watershed to their condition.
7. I can define limnology and explain what a
limnologist does.
8. I understand what is meant by "temperature
stratification" and can describe how it explains
why lakes don't freeze from the bottom to the
top. Also I can name the temperature at which
water is the heaviest.
9. I can identify factors that affect the levels of
dissolved oxygen in a lake.
10. I can demonstrate the use of the Secchi disc.
Lakes and Ponds Have 3
Main Sources of Water
T6
1. ______________________
2. ______________________
3. ______________________
-The amount of water in a lake or pond depends
on the _____________________
___________*: includes lake/stream/river and
all surrounding land which drains toward it
*Any area of the watershed may contribute
water and pollutants to that
lake/stream/river
Watershed Animation
LIMNOLOGY
• Scientific study of
T7
_______________________________,
especially lakes, ponds, and streams
• Limnologists study factors which affect
fresh bodies of water
ABIOTIC PROPERTIES
T8
Temperature
-Many Illinois lakes are deep enough to
__________ (form “layers” w/ different temps
-Occurs because water density changes with
temperature
-Water is heaviest at __________ –>
above/below this temperature, water
becomes less dense
-In fall, surface water cools to 4oC and ______
-As lake continues to cool, colder water “floats”
on top and forms ice
SPRING TURNOVER
T8
• Occurs when ice melts and surface water
warms above 32oF (0oC)
• Wind action and increasing density of
warming water cause surface water to
sink and mix with deeper water
Winter
Spring
Autumn
Summer
4º
2º
4º
4º
4º
4ºC
0º
4º
4º
4º
4º
4º
4ºC
Thermocline
20º
18º
8º
6º
5º
4ºC
22º
4º
4º
4º
4º
4ºC
SUMMER LAYERING
T8
• Occurs in lakes deeper than 10 feet
• The lake “stratifies” into three layers of water – called
_______________________
A. _________________ - circulating warm water. Oxygen
levels medium to high. Fish often confined to this zone
which may be up to 20 feet deep.
B. ____________ - zone of rapid temperature and oxygen
change. Fish will select this zone if oxygen is present.
C. ______________ - cold, non-circulating water. Oxygen
levels are low or absent. Fish cannot live here very long
due to low oxygen levels.
Lake Stratification Animation
Dissolved Oxygen (D.O.)
• Oxygen enters a lake 2 ways:
– __________________________
– __________________________
T9
4 factors that affect D.O. levels:
• _________________
• _____________ mixing
across lake surface
• Amount of decomposing
matter (BOD)
-_______________
____________________
-↑ decay = ↓ Oxygen
• Temperature
______________
-Lower oxygen in
hypolimnion (WHY?)
T9
T18
Total Suspended Solids (T.S.S.)
T10
• Concentration of all materials suspended in a lake
• EXAMPLES: erosion of rocks and soil
algae
decaying plants and animals
SECCHI DISC
Using a Secchi Disc Video
Targets: Freshwater Ecosystems
11. I can explain how the amounts of phosphorus and nitrogen
in a lake can affect it.
12. I can draw the pH scale, label where acids and bases
range, identify what pH is neutral and what the pH is for
the strongest/weakest acids and bases and state the pH
of most Illinois Rivers.
13. I can label the following areas: LITTORAL COMMUNITY,
LIMNETIC COMMUNITY, PROFUNDAL COMMUNITY
14. I can recite the differences between the following lake
types: OLIGOTROPHIC, MESOTROPHIC, EUTROPHIC,
HYPEREUTROPHIC.
15. I can explain the differences between Point and
Nonpoint Source Pollutants.
Phosphorus and Nitrogen
• Amounts of phosphorus and nitrogen in a lake
•
•
•
control _____________________
Algal Blooms
EXCEPTION: Ammonia, form of N produced
during decomposition, can kill aquatic life
SOURCES: sewage
fertilizers
detergents
T11
pH
• Review of pH Scale
• Most lakes have pH of 6.5 –> 9
• Rainwater in Illinois is acidic
(~4.4), but most of our lakes
are able to offset this
because of natural
buffering compounds in
the lake water and
watershed
T12
BIOTIC FACTORS
Lake ecosystems divided into 3 separate communities:
T13
1. ________________________
-extends from shoreline
-a lot of plant and animal growth
-bottom-dwelling insects; submerged, floating-leaf and emergent
plants; fish and frogs
2. ________________________
-”open” water area
-phytoplankton, zooplankton and fish
3. ________________________
-little or no sunlight and low in oxygen
-bacteria and fungi found here
COMMON LAKE PROBLEMS
• __________________
-Lake filled with nutrients 
More plants grow
-Decaying plants cause lake to
fill in (100’s of years to occur)
-Lakes are classified as:
A. __________________:
“young” lake; clear with little
plant growth
B. ___________________:
a little older; more plant life
C. ___________________:
“old” lake; peak of plant
growth; filled with fish and
other animals
D. __________________:
humans cause by using
fertilizers or causing soil
erosion (also called Cultural
Eutrophication)
Eutrophication Video
T14/
T17
Other Lake Problems . . .
T15
• Pollutants (2 Types)
A. ________________: discharge from factories
and sewage treatment plants
B. ____________________: stormwater, run-off
from land, septic systems, also duck, goose and
livestock wastes
• ________________________________
Targets: Wetlands
1. I can define a wetland.
2. I can list the 2 ways wetlands are formed.
3. I can describe the 3 major things to
consider when determining if an area is a
wetland.
4. I can describe the 4 features used to
classify different wetland types.
5. I can name the most important
environmental factor determining the
kinds of plants living in a particular
wetland.
What Are Wetlands?
• Have natural supply of
•
•
•
•
water.
Cover 6% of Earth’s land
surface
Water sources include tidal
flows, flooding rivers, or
groundwater
Covered/soaked with water
for at least part of the year
Between terrestrial and
aquatic ecosystems
Wetlands Video
T1
Illinois Wetlands
• In the Midwest, wetlands were
formed 2 ways:
-_________
-________
T2
How do you know a wetland?
• 3 major things to consider when determining if
•
an area is a wetland:
1. ____________
2. ____________
3. ____________
One factor may be enough to determine the
presence of a wetland; but if more factors exist,
there is a much better chance that a wetland
environment is present.
T3
The Water
• An area may look completely
dry and still be a wetland
• A wetland is any area that is
flooded or saturated with
water for at least _________
of the plant growing season.
T3
The Soil
• _______________
–Waterlogged
–Low in oxygen
T3
The Plants
T3
• ____________: plants adapted
to life in water or saturated
soil
Classification of a Wetland
• Once you determine an area is a
T4
wetland, you must study 4 things in
order to classify what type of wetland
it is . . .
1.______________________
2.______________________
3.______________________
4.______________________
Types of Wetland Soils
2 types of wetland hydric soils:
1. _____________________
-Made of sand, silt, clay, and elements
such as iron and manganese
-Upper layer gray with specks of red,
black or yellow.
-Often second layer is gray, green gray,
or bluish gray.
2. ______________________
-Also called “peat” or “muck”
-Thick layer of slowly decaying plants
-Dark brown
T4
Water Supply (Hydrology)
T4
• Water will be supplied to a wetland by either . .
– ____________________
– ____________________
Wetland Plants
(Hydrophytes)
T5
• Water __________ (rainfall) determines
what plants will live in a wetland
•  water depth =  plant diversity
Comprehension Check
• Name the 3 things that would be studied to
determine IF an area were a wetland?
– Hydric Soil
– Hydrophytes
– Saturated soil 7.5% of plant growing season
• Once it has been shown that an area is a
wetland, what 4 things must be studied to
determine what TYPE of wetland it is?
–
–
–
–
Climate
Organic vs. Mineral Soil
Water supply
Organisms present
• How were wetlands formed in Illinois?
– Glaciers
– Rivers
Targets: Wetlands
6. I can name, define and give examples
for the six main types of wetland plants.
7. I can recite the EIGHT wetland types and
list 2 main distinguishing traits of each:
8. I can write out a food chain with at least
4 organisms that could be found in a
wetland.
9. I can name 3 beneficial things wetlands do
for humans and the environment.
Wetland Plant Types
1. __________________
-Example: water lilies
-rooted deep below
water with broad, flat
leaves that rest on
water’s surface
T6
2. _________________
• Example: Duckweed
• Not rooted, but
remain on the water’s
surface, with dangling
roots
T6
3. __________________
• Example: cattails
• Grow with roots in wet soil and send up
leaves that stand ABOVE water’s surface
T6
4. __________________
• Example: Pond weeds (Elodea)
• Rooted in soil and stems/leaves remain
completely under water
T6
5. Moist-soil Plants : sedges and buttonbush
T6
6. Moist-forest trees: tamarack, bald cypress
and silver maple
-These live in the drier portions of wetlands
Wetland Classification: some wetlands
contain all of these plant types, but others
only have one or two
Hydrophytes
T6
Types of Wetlands
1. ______________________
-occur along streams and
rivers
-frequently flooded
-many rotting logs
-mineral soils
-trees include silver maple,
cottonwood, red maple
and sycamore
T7
T7
2. _________________
• Dominated by
emergent plants
• Water depths
range from 0
(saturated soil) to
6 feet
• Organic soils
T7
3. ______________________
• Dominated by trees
• Top layer of soil is
organic with mineral
soil beneath
• Found in southern
Midwest
4. ____________
• Found in northern Midwest
• Formed by glacial depressions
•
•
•
•
•
with poor drainage
May be forested, grassy or have
shrubs
Highly acidic soil
Plants include sphagnum moss,
orchids, poison sumac, tamarack
and carnivorous plants (sundew
& pitcher plant)
Organic soils
“Peat” forms a floating mat over
the water
T7
5. _______________
• Form from groundwater
that can’t penetrate
downward
• Water is only from
underground sources
T7
6. ___________
• A wet meadow fed by a seep
• Must have soils with neutral or basic pH
• Organic soils
T7
T7
7. ___________________
• Organic soils saturated with water
• Drier than fens
• Some standing surface water is usually
present in winter and spring
• Most have been drained and are now
farmed
8. ______________
• A depression between slopes that provides
T7
for drainage
• Occur around the sandy shores of the Great
Lakes
• Usually contain grasses
T8
Food Chains in a Wetland


algae  mayfly nymph 

pickerel  Great Blue
heron
Think about this before the
next slide . . .
Determine which TWO
functions of a wetland are
the most important for the
the village of Lake Zurich
and WHY.
Environmental Functions of
Wetlands
T9
Targets: Marine Ecosystems
1. I can explain why the ocean appears blue.
2. I can compare the difference between ocean
tides and currents. I can explain what causes
each.
3. I can define what an estuary is and why estuaries
are important to the environment.
4. I can describe what brackish water is and what
happens when fresh and salt water combine.
5. I can label the major zones found in the ocean.
6. I can explain the difference between a sea and
ocean.
7. I can describe advantages and disadvantages to
living in the intertidal zone.
8. I can identify and label the 5 major oceans on a
world map.
OCEANS
Most Commonly Asked Questions
T1
• Why is the ocean blue?
-Water absorbs more of the ________________ in
sunlight
-Seawater does not absorb ___________________,
so blue light is reflected outwards
Some Oddly-Colored Seas:
The Red Sea often looks red
because of red algae that live here
The Black Sea looks almost black because it has a high
concentration of hydrogen sulfide (which appears black)
Why is the ocean salty?
• Run-off water picks up salt and carries it to
rivers
• Rivers carry it to seas
• Since this has been happening for millions of
years, the oceans now have a lot of salt—
about one cup per gallon!
T2
Tides
• __________ rising and
lowering of sea level
• Greatly controlled by
gravitational pull of sun and
moon.
• Although sun has a stronger
gravitational attraction than
moon, the ________ is closer to
earth so its gravitational pull is
twice as strong as the sun’s.
How does the Moon
Affect Ocean Tides?
• Gravitational pull of moon
creates two tides: high and
low
• Gravitational attraction of the
moon causes oceans to bulge
out toward it
• Another bulge occurs on
opposite side, since Earth is
also being pulled toward the
moon (and away from the
water on the far side)
T2
Tidal Facts . . .
T2
• Tides are highest when there is a full or new moon.
• If you are on the coast and the moon is directly
•
•
overhead, you will experience a _____________
If the moon is directly overhead on the opposite
side of the planet, you should also experience a
high tide.
During the day, Earth rotates 180 degrees in 12
hours and the moon rotates 6 degrees around the
earth in 12 hours.
– This means any given coastal city experiences a
high tide every ___________________________
Currents
• _________ circulation of ocean waters
• Major causes of ocean currents include:
T2
– ____________________
–____________________
–____________________
Estuaries - Where Rivers Meet
the Sea
• Partially enclosed body of water
•
•
where seawater is mixed with
fresh water 
_______________________
Examples: bays, sounds, salt
marshes, mangrove forests,
mud flats, swamps, and inlets
Transition from fresh to salt
water, a small disturbance here
can cause serious problems
T3/4
Estuaries are important
ecosystems:
• _________________________
•
– Remove sediments/nutrients from
rivers before water reaches ocean
– Prevent valuable soil and nutrients
from being flushed into open seas
where they could not be used
__________________________
– Act as natural buffers between land
and ocean
– Porous soils/grasses absorb flood
waters and buffer storms
– Help protect human lives, upland
animals, and real estate
T3
Zonation in the Ocean
• _______________:
•
•
ocean bottom
_______________:
the water itself (water
column)
Pelagic zone divided
into the
_______________
and the
_______________
T5
Oceanic zone divided into 3 levels based
on amount of sunlight they receive.
• _________________ =
sunlight penetrates to
allow photosynthesis
• __________________=
very small amounts of
light penetrate
• _________________ =
90% of the space in
ocean lies in midnight
zone, which never
receives sunlight
T5
T5
T6
What is a sea?
•A branch of one of the five
"oceans"
•Partially enclosed by land
What are the world's largest
seas?
1. The South China Sea
2. The Caribbean Sea
3. The Mediterranean Sea
T6
The Intertidal Zone
• Area exposed between high and low tides
• Part of day spent in open air and rest spent
•
T7
covered in water
Some advantages:
– _____________________________________
– _____________________________________
How many oceans are there in the
world?
• There is really only one big ocean.
• One can sail in a boat to every
•
known "ocean" and "sea“
Five main areas in one big ocean:
1.Pacific Ocean
2. Atlantic Ocean
3. Indian Ocean
4. Southern Ocean: at
Antarctica and South Pole
5. Arctic Ocean: surrounds
North Pole, smallest
"ocean“, frozen most of the
time, except at its edges
T8
T8
Identifying the World’s Oceans