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OCEANS
World’s oceans cover 71% of the
Earth’s surface
WATER DENSITY
Salt content and water temperature
affect water density
WATER DENSITY
More dense (heavier) – colder and
saltier
Less dense (lighter) – warmer and
less salty
CURRENTS
Currents driven by heating and cooling,
gravity, and water density
Great Ocean Conveyor
UPWELLING & DOWNWELLING
Upwelling – vertical flow of cold,
nutrient-rich water toward the
surface
Horizontal currents
diverge
UPWELLING & DOWNWELLING
Downwelling – surface waters sink
Surface currents
converge
Warm water
pushed down
OCEAN STRUCTURE
3 zones photic, aphotic, and benthic
3 zones of the
photic zone
Intertidal
Neritic
Open ocean
3 PHOTIC ZONES
Intertidal zone
High tide line to the lowest low tide
line
Intertidal organisms have to be able
to withstand being submerged in
water, beat by waves, being exposed
to the air and sun
INTERTIDAL
ORGANISMS
3 PHOTIC ZONES
Intertidal zone (cont’d)
Nutrient rich
Large number of organisms some
burrow into the sand until high tide
returns
3 PHOTIC ZONES
Neritic ecosystem
Extends from low tide mark to the
edge of the continental shelf
Sunlit
Most productive ecosystems
Kelp forests
Coral reefs
NERITIC ECOSYTEMS
NERITIC ZONE
Kelp forest
Supplies shelter and food for
invertebrates
Invertebrates provide food for
predators
Absorbs wave energy and protects
shores from erosion
NERITIC ZONES
Coral Reefs
Shallow tropical & subtropical
Tiny invertebrates
Get nourishment from symbiotic algae
Corals die and leave behind their
calcium carbonate skeleton
Protect shorelines
OPEN OCEAN
Begins at the edge of the continental
shelf
Least productive ecosystem!
OPEN OCEAN
Limited photosynthesis occurs
Phytoplankton are typically the base
of food chains in the open ocean
Eaten by zooplankton
Eaten by fish, jellyfish, whales, etc
These can be become food for
predators
OPEN OCEAN
Animals have many adaptations that
allow them to live in the dark and
cold parts of the ocean
BENTHIC ECOSYSTEMS
Rely on hydrothermal vents
Bacteria use the energy from the
heated water that flows from the
vents
Many species feed on the bacteria and
the food chain can continue
tubeworms
HYDROTHERMAL
VENTS
vents