Download ocean zones

OCEAN ZONES
• ZONES OF THE WATER COLUMN
•
FEATURES OF THE OCEAN FLOOR
• OCEAN BIOMES
Pelagic
Four Zones
of
Interest
Intertidal
Abyssal
Benthic
ZONES OF THE WATER
COLUMN
• Intertidal: the area between high tide and
low tide. Sometimes covered, sometimes
exposed, a very tough habitat to live in.
Subjected to drying and submersion,
temperature extremes, the pull of the
waves, and sea and land predators.
Animals often burrow or have hard shells
that can be sealed to prevent water loss.
Plants usually cling to hard bottoms.
Intertidal zone creatures
High Tide
Low Tide
Another view– zones in zones
Zones of the Water Column
• Pelagic zone: Open ocean zone.
Usually sub-divided by depth or
amount of sunlight. The upper pelagic
receives sunlight, so there are many
phytoplankton for photosynthesis.
Zooplankton, jellyfish, squid, and
fishes of all sizes make up the food
chain. The lower reaches receive less
or no sunlight, so there are no plants
and animals are often
bioluminescent (make their own
light).
Pelagic Zone
Inhabitants of the Pelagic Zone
A Pelagic Food Web
BENTHIC
PELAGIC
Zones of the Water Column
• Abyssal: The midnight zone of the ocean–
no light penetrates. The pressure at 10,000
ft. would be like you having 5 jumbo
airliners on your back. Animals are adapted
to withstand the dark, the cold (near
freezing), and the tremendous pressure.
That’s why they usually don’t survive the
trip to the surface. Most are dark or nearly
transparent in color, and are
bioluminescent. They don’t move much, and
usually eat what falls from above. Jaws are
big to swallow large objects whole.
Monsters of the Abyss
The Abyss
A very hostile environment
Increasing Cold
Increasing Pressure
Fantastic
Denizens of
the Deep
ZONES OF THE WATER COLUMN
• Benthic: a term meaning bottom, is the ocean
zone ranging from the deepest part of the
ocean to the shore. Many kinds of organisms
live in the benthic zone– plants, anemones,
sponges, fish, skates and rays, octopus,
mollusks, crabs, sea stars, corals and worms.
Most are scavengers. In the deep ocean, there
are special benthic communities around
hydrothermal vents whose energy comes
from chemical reactions rather than from the
sun.
Benthic Zone– from the shore to
the depths
BENTHIC
PELAGIC
Intertidal Benthic
Hydrothermal vent
Coral Reef
Hydrothermal Vents
In 1977, the submersible Alvin
found seafloor vents that were gushing
hot mineral-rich water in the midnight
depths of the ocean.
Cold sea water seeps into cracks in the
Earth’s crust and is superheated by the
magma in the mantle. The hot water with
dissolved minerals from the magma rises
and spews out like an undersea geyser .
Cold water and chemical
reactions cause mineral
deposits to settle out as
vent chimneys.
Fantastic communities of
organisms that live by
chemosynthesis thrive
around these “black
smokers”, using energy
from chemical reactions with
minerals in the water to live.
OCEAN ZONES
•
ZONES OF THE WATER COLUMN
• FEATURES OF THE OCEAN FLOOR
•
OCEAN BIOMES
Features of the Ocean Floor
•
What do you think the ocean floor looks
like?
Is it flat? Saucer-shaped? Mountainous?
•
The same mountains, valleys, plains,
trenches, and pits we see on land are also
on the ocean floor.
The tallest mountains, the deepest
valleys, and the flattest plains on
earth are all on the ocean floor!
Features of the Ocean Floor
• Continental shelf: surrounds the continent as
a shallow extension of continental crust
extending out to the continental slope.
• Continental slope: steep drop-off at the end of
the continental shelf that connects the
continental crust to the oceanic crust.
• Together, they make up the continental
margin.
Features of the Ocean Crust
• Abyssal plains: are the flattest areas on earth.
• Ocean ridges: are long mountain ranges
formed when magma seeps or erupts between
pieces of the Earth’s crust (tectonic plates).
• Trenches: are the deepest part of the ocean
and are formed when one tectonic plate is
forced under another tectonic plate.
• Seamounts: isolated volcanic mountains which
erupt under the ocean. Large ones are islands.
• Guyots: are extinct volcanoes with eroded flat
tops.
The highest mountain
on Earth is Mauna Kea,
Hawaii, a seamount
Ocean ridges form a
mountain chain 40,000
miles long through all the
oceans
The average
depth of the
ocean is 12,200
feet (3,720 m.)
Trenches form where
tectonic plates (chunks of
the Earth’s crust) are
forced under another plate.
The Mariana Trench in the
western Pacific is the
deepest point on Earth–
36,198 ft. (11,033 m.)
Trieste and the
Mariana Trench
In 1960, the US Navy sent a
small submersible (mini-sub)
to see how far down it
could go. It sat on the
bottom at 35,838 ft.
(10,923 m.) The sailors had
7 miles of water over their
heads!
OCEAN ZONES
•
•
ZONES OF THE WATER COLUMN
FEATURES OF THE OCEAN FLOOR
• OCEAN BIOMES
Ocean Biomes
• Can be divided by zones: intertidal,
pelagic, and abyssal. Benthic organisms
are the bottom dwellers in each zone.
• Each zone requires different adaptations
for survival. Organisms are specialized to
live in a particular zone.
• Like in land biomes, similar types of flora
and fauna live in similar types of biomes
across the world oceans.
Pelagic
Intertidal
Abyssal
Benthic
Other Aquatic Biomes
• “Aquatic” means water.
• Other aquatic biomes besides the ocean
(marine biome) are freshwater and estuarine.
• Freshwater is water with no salt, and includes
rivers, lakes, ponds, etc.
• Estuaries are environments where salt water
and fresh water meet. The salinity (amount of
salt) varies with the tides and the seasons.
• Estuaries are often warm, shallow, protected
places that serve as nurseries for marine
organisms.
Freshwater
Marine
Estuary
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