Marine Ecosystems
Ocean coasts support
plant and animal life
 Habitat – an environment that has all necessary
requirements for an organism to live.
 Intertidal Zone – the habitat at the edge of the
ocean.
 Estuaries – the place where fresh water from
rivers and streams mixes with salt water from
the ocean.
 Wetlands – wet, swampy areas that are often
flooded at the edge of estuaries.
ECOLOGICAL ADVANTAGES
 Climate moderation
 CO2 absorption
 Nutrient cycling
 Waste treatment and dilution
 Reduced storm impact (mangrove,
barrier islands, coastal wetlands)
 Habitats and nursery areas for marine and
terrestrial species
 Genetic resources and biodiversity
 Scientific information
ECONOMIC ADVANTAGES
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Food
Animal and pet feed (fish meal)
Pharmaceuticals
Harbors and transportation routes
Coastal habitats for humans
Recreation
Employment
Offshore oil and natural gas
Minerals
Building materials
Types of Marine Ecosystems
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Estuaries
Salt marshes
Rocky shores
Sandy Shores
Coral reef
Mangrove swamp
Barrier islands
Estuaries
An area in which fresh water from a river mixes
with salt water from the ocean; a transition area
from the land to the ocean. Other names: bay,
sound, lagoon, harbor, or bayou.
The Ocean
Area where
fresh and salt
water mix
River bringing
freshwater to
the sea
Characteristics of
Estuaries
 Water is brackish : a mixture of freshwater and
saltwater
 There is a gradual increase in salinity as you
go from the river (0-5ppt) to the middle of the
estuary (5-25ppt), to the ocean (>25 ppt).
(ppt = parts per thousand, a unit for salinity)
 Pollutants are absorbed in estuaries.
Characteristics of
Estuaries
 Very nutrient rich ecosystems  leads to high
productivity and high biodiversity.
 Fast-moving rivers and waves carry nutrientrich particles.
 Sediment settles out in the estuary when the
water slows down.
 Nutrients accumulates on the bottom (benthic
zone).
 Great place for plants to grow!
Estuary plants
Plants must be adapted to salty habitat
eelgrass
cordgrass
glasswort – a succulent
Estuary animals
Huge variety including…
Blue crab, Stone crab, Fiddler crab,
Horseshoe crab, Mosquito, Lobster,
Flounder, Stripped bass, Crane,
Flamingo, Sea gull, Ibis, Manatee,
otters, and many more.
Salt Marshes
 A low area that is subject to regular, but gentle,
tides, dominated by grasses.
 Salt marshes do not have trees or shrubs
 Location: Gulf of Mexico and Atlantic coast
Texas salt marsh
Mangrove
Swamps
Coastal wetlands
located in tropical
and subtropical
zones; characterized
by salt-tolerant trees
and shrubs, such as
mangrove trees
Rocky shores
Also called rocky intertidal zone – many places to
live in this habitat, means high biodiversity
Organisms must be adapted to wave action,
changing tide levels
Rocky Shores
At low tides, there are often tide pools left
behind where you can see starfish,
anemones, crabs, octopus
Sandy Shores
Not as much biodiversity as rocky shores – Why?
1. not much habitat diversity
2. sand dries out at low tide
some small things can live in the sand, food for
shorebirds
Barrier Islands
Narrow islands made of
sand that provide a
buffer for the mainland
from the sea
Constantly shifting,
especially with storms
Ex: North Carolina
OuterBanks
Barrier
beach
Beach flea
Peanut worm
Tiger beetle
Blue crab
Clam
Dwarf
olive
High tide
Sandpiper
Silversides
Mole
shrimp
Low tide
White sand
macoma
Sand dollar
Moon snail
Ghost
shrimp
Barrier Islands
Ocean
Beach
Primary Dune
Intensive recreation,
no building
Trough
Secondary Dune
No direct
Limited
passage
recreation
or building and walkways
Grasses or shrubs
No direct
passage
or building
Taller shrubs
Back Dune
Bay or
Lagoon
Most suitable
for development
Intensive
recreation
Bay shore
No filling
Taller shrubs and trees
Think about ecological succession as you move
away from the ocean. What is the “disturbance”
in this ecosystem?
Coral Reefs
 Structures in the shallow oceans that are built
by animals called corals; serve as a habitat for
many diverse organisms
 Require two things: warm temperatures and
sunlight
 Found between 30°N and 30°S of the equator
Coral Reefs
There are many different kinds of corals:
Soft corals
Hard corals
Coral Reefs
Growing on the reef with
the corals are other
animals, such as
sponges, worms,
shrimps, crabs,
mollusks
Living in and around the
reef are fish, sea
turtles, sea snakes,
marine mammals
Coral Reef Destruction
1. Coral bleaching – when
temperatures go above
normal, the algae in the
coral can be rejected,
the coral turns a whitish
color and dies.
Natural and/or manmade
causes: El Nino, Global
warming
Coral Reef Destruction
2. Physical damage
Ships, anchors, tourist divers
Dynamite fishing - reefs are damaged by
physical destruction that may occur when
people collect fish
Coral Reef Destruction
3. Land development and pollution – loss
of mangrove forests means more
nutrients and sediments flow out to the
sea; coral may die from sediment or
algal blooms
4. Fish and coral trade
5. Increased exposure to UV due to ozone
depletion
Human Interactions Effect
Shorelines
 Half of coastal wetlands lost to agriculture
and urban development
 Over one-third of mangrove forests lost
since 1980 to agriculture, development, and
aquaculture shrimp farms
 About 10% of world’s beaches eroding
because of coastal development and rising
sea level
 Ocean bottom habitats degraded by
dredging and trawler fishing boats
Human Interactions Effect
Shorelines
 Over 25% of coral reefs severely damaged
and 11% have been destroyed
UPWELLING
Winds blowing across the ocean surface push
water away. Water then rises up from beneath
the surface to replace the water that was
pushed away.