Transcript Aquatic Ecosystemsx

Aquatic Ecosystems
Habitats
• Surface film:
This is the place where the water meets the air. Animals found here
include air-breathing insects that may walk on or hang from the
surface of the water.
Open Water:
The area where rooted plants do not reach the surface of the water. In
this habitat you will find fish, turtles , and water birds
Habitats:
• Bottom-the area of rocks, sand, or mud that is the habitat for a
variety of small organisms including bacteria, snails, worms,sponges,
crayfish, and the larvae of some insects.
• Water’s edge-is where the water meets the land. This area is home
for the greatest number of species of plants and animals.
Deep Lake Zones
• Deep lakes contain three distinct zones, each with a characteristic
community of organisms:
• Limnetic zone-The layer of open water where the sun’s light reaches
and photosynthesis can occur
• Profundal zone-The area that is deep enough that not enough light
reaches to support primary productivity
• Littoral zone-The zone closest to shore
Limnetic zone
• This is the zone of open water
where photosynthesis can occur.
Also known as the photic zone.
• Life in the limnetic zone is
dominated by
• Floating microorganisms called
plankton
• Actively swimming animals
called nekton
Profundal Zone
•Many lakes, and a few ponds, are
so deep that a zone exists where
not enough light reaches for
photosynthesis to occur.
•This zone depends on things that
drift down from above for its
calories.
•This zone is inhabited chiefly by
primary consumers that either
attach to something or crawl along
the bottom
•Such bottom dwellers are called
benthos
Littoral Zone
• The zone closest to shore
• Here light reaches all the way to
the bottom
• Producers in the zone include
algae and plants that are rooted
to the bottom
• Consumers include crustaceans,
larvae, flatworms, snails, frogs,
turtles and others
Creatures that live in the water:
• Benthic macroinvertebrates: aquatic insects or other small
organisms that have no backbone and are large enough to be seen
without a microscope.
• Benthic- means that their habitat is at the bottom of the water
• A survey of the benthic macroinvertebrates in a body of water can be
an indication of the quality of the water since some of them can only
be found in clean water.
Macroinvertebrate survey
• Clean water organisms-some organisms will only be found in the
cleanest of pond water. They cannot tolerate any pollution
• Pollution-tolerant-some species can tolerate polluted water
• Index species-certain organisms are called index species because
their presence in large numbers can tell us whether the water is clean
or polluted
Macroinvertebrate Diversity
• The diversity of macroinvertebrate populations is a good indicator of
the health of the ecosystem.
• In general, the more species found in an area, particularly the more
sensitive species, the healthier the ecosystem
• If a body of water is found to be decreasing in its diversity it can be
assumed that it is most likely because of some environmental stress
(human interference, drought, extreme temperatures etc)
FRESHWATER LIFE ZONES
• Freshwater life zones
include:
• Standing (lentic) water
such as lakes, ponds, and
inland wetlands.
• Flowing (lotic) systems
such as streams and
rivers.
Figure 6-14
Natural Capital
Ecological Services of Rivers
• Deliver nutrients to sea to help sustain
coastal fisheries
• Deposit silt that maintains deltas
• Purify water
• Renew and renourish wetlands
• Provide habitats for wildlife
Fig. 12-11, p. 267
Freshwater Wetlands
Wetland definition:
• Covered by water all or part of the year
• Characteristic hydric soils (saturated)
• Characteristic plant life (plants that are adapted to having their roots
covered by water part of the time)
Freshwater Inland Wetlands:
Vital Sponges
Filter and degrade pollutants.
 Reduce flooding and erosion by absorbing
slowly releasing overflows.
 Help replenish stream flows during dry
periods.
 Help recharge ground aquifers.
 Provide economic resources and recreation.

Swamps
• A lowland region permanently covered
with water.
Importance of freshwater wetlands
• They filter & purify water.
• Habitat for many animals and plants.
Definition
Estuaries
• A partially enclosed area of coastal water
where sea water mixes with freshwater.
Salt Marshes
• The ground here is saturated with water and there is little
oxygen, so decay takes place slowly. It has a surface inlet
and outlet, and contains many invertebrates. It is also the
breeding ground for many ocean animals. Ex. crabs and
shellfish.
Mangrove Forests
• These are along warm, tropical coasts
where there is too much silt for coral
reefs to grow. It is dominated by salttolerant trees called mangroves (55
different species exist). It also helps to
protect the coastline from erosion and
provides a breeding nursery for some
2000 species of fish, invertebrates,
and plants.
The Everglades
Southern Florida to the Keys
Case Study:
Restoring the Florida Everglades
• The world’s largest ecological restoration project involves
trying to undo some of the damage inflicted on the
Everglades by human activities.
• 90% of park’s wading birds have vanished.
• Other vertebrate populations down 75-95%.
• Large volumes of water that once flowed through the park have
been diverted for crops and cities.
• Runoff has caused noxious algal blooms.
Problems
• As Miami develops, it encroaches on everglades. Plus, it
prompts people vs. wildlife. It is freshwater and local areas
are draining it.
Restoring the
Florida
Everglades
• The project has
been attempting to
restore the
Everglades and
Florida water
supplies.
Figure 12-10
Restoration
• Build huge aqueduct, or find other
sources of fresh water an protect it
federally under endangered species act,
etc.
Case Study: The Aral Sea Disaster
• Diverting water from the Aral Sea and its two feeder
rivers mostly for irrigation has created a major
ecological, economic, and health disaster.
• About 85% of the wetlands have been eliminated and roughly
50% of the local bird and mammal species have disappeared.
• Since 1961, the sea’s salinity has tripled and the water has
dropped by 22 meters most likely causing 20 of the 24 native
fish species to go extinct.
Colorado River Basin
• These are dams &
reservoirs that feed from
the Colorado River all the
way to San Diego, LA,
Palm Springs, Phoenix &
Mexico. So far has
worked because they
haven’t withdrawn their
full allocations. See
pg306.
The Colorado River Basin
• The area drained
by this basin is
equal to more
than one-twelfth
of the land area of
the lower 48
states.
Figure 14-14
IDAHO
WYOMING
Dam
Aqueduct or
canal
Salt Lake City
Upper Basin
Denver
Grand Junction
UPPER
BASIN
Lower Basin
UTAH
NEVADA
Lake
Powell
Grand
Canyon
Las Vegas
COLORADO
Glen
Canyon Dam
NEW MEXICO
Boulder City
CALIFORNIA
Los
Angeles
ARIZONA
Palm
Springs
San
Diego
All-American
Canal
Albuquerque
LOWER
BASIN
Phoenix
Yuma
Mexicali
Gulf of
California
Tucson
0
100 mi.
0
150 km
MEXICO
Fig. 14-14, p. 318
Case Study: The Colorado Basin – an
Overtapped Resource
• The Colorado River has so many dams and
withdrawals that it often does not reach the
ocean.
• 14 major dams and reservoirs, and canals.
• Water is mostly used in desert area of the U.S.
• Provides electricity from hydroelectric plants for 30
million people (1/10th of the U.S. population).
Case Study: The Colorado Basin – an
Overtapped Resource
• Lake Powell, is the
second largest
reservoir in the U.S.
• It hosts one of the
hydroelectric plants
located on the
Colorado River.
Figure 14-15