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Oceanography
I. Introduction to Oceans
A. Oceanography – the study and
exploration of the world’s oceans.
B. Formation of the ocean waters –
water vapor and condensation of
vapor as rain in the ocean basins
II. Properties of Ocean Water
A. Composition of Ocean Water
1. H2O is 96.5 %
2. other elements is 3.5%
3. salinity – dissolved salt content of a body of
water
B. Temperature of Ocean Water
1. as temperature increases, density decreases
2. surface temperature – from 2OC (Arctic) to 28OC
(equator)
3. subsurface temperature – from 1OC to 3OC

4. thermocline – zone where there is a sharp
difference in temperature between surface and deeper
water.
C. Pressure – pressure increases as the ocean depths
increases
D. Color – natural color is blue, but can be affected
by pollutants or microscopic plants
III. Oceans – a continuous body of saltwater that
covers approximately 70% of the Earth
A. PACIFIC – the largest, deepest, covers
1/3 of the Earth’s surface, contains
approximately ½ of the Earth’s water.
B. ATLANTIC – second largest, contains
Mediterranean, Caribbean and North
Seas, shallower than Pacific and Indian
C. INDIAN - deeper than the Atlantic,
shallower than the Pacific
D. ARCTIC – surrounds the geographic
North Pole
IV. Life in the Ocean
A. Plankton – drifting organisms in aquatic
environments (marine and freshwater). The base of
the food web in these environments
1. phytoplankton – plant plankton – example –
diatoms
2. zooplankton – animal-like plankton exampleprotists, crustaceans
B. Nekton – organisms that swim in the ocean freely.
examples – larger fish, squid, sea turtles, whales
C. Benthos – community of organisms that live on, in, or
near the ocean floor
examples – crabs, coral, starfish, clams, sea
anemones
1. benthic environment – region near or at the
bottom of a pond, lake, or ocean, including
organisms that live there
2. pelagic environment – ecological realm that
includes the entire ocean water column
Threats to the Ocean


The oceans are huge but are
becoming increasingly more
polluted.
Overfishing is also destroying fish
populations.
V. Marine Ecosystems

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Includes: estuaries, coral reefs,
oceans, and polar ecosystems
Marine ecosystems contain
salt
dissolved _____.
In oceans, lack of water is not a
problem. Therefore, the types of
organisms present are dependent
temperature
upon __________,
sunlight
nutrients
available, and ___________.
Estuaries



fresh _____
water from rivers
An ecosystem where _____
salt water
and streams mixes with _____
_____ from the
ocean.
Estuaries contain plenty of light and nutrients
which support large populations of plants and
animals.
Plants and animals that live in estuaries are
salinity because
able to tolerate variations in ________
salt content of the water varies as the
the _____
fresh and salt water mix.
Threats to Estuaries


Estuaries provide harbors, access to
the ocean, and connections to
rivers. As a result, many of the
world’s largest cities are built on
estuaries.
Because of this, many estuaries
have become polluted.
Estuaries
Coral Reef



limestone
Coral reefs are __________
islands in the
sea that are built by coral animals called
polyps.
Thousands of species of plants and
animals live in the cracks and crevices of
coral reefs, making coral reefs among the
diverse ecosystems on Earth.
most ________
warm salt water
Corals can only live in _____
light for
where there is enough ______
photosynthesis. Therefore, coral reefs
are only found in shallow, tropical seas.
Threats to Coral Reefs



If the water surrounding a reef is too hot
or cold, or if fresh water drains into the
water surrounding a reef, corals have
trouble producing limestone.
If the water is too muddy, too polluted, or
too high in nutrients, algae that live
within the corals will die or grow out of
control and smother the corals.
Oil spills, sewage, pesticide, and silt
runoff have all been linked to coral reef
destruction.
Coral Reefs
Polar Ecosystems



The ice-covered polar caps can be
considered marine ecosystems
because nearly all food is provided
by phytoplankton in the ocean.
North
The ______
Pole is in the Artic
South
Ocean and the ______
Pole is in
Antarctica.
Plankton
________
provides the main source
of food at both poles.
Threats to Polar Ecosystems


Oil extraction, tourism, and garbage
are the worst threats to the polar
ecosystems.
Conservationists want these areas
to become world wildlife refuges.
VI. Upwellings
Upwelling refers to deep water that is brought to the
surface.
Areas of upwelling are created by surface winds that pull
water away from an area. This deficit of water on the
surface invites water to come up from deeper regions.
To understand upwellings, you must be familiar with how
the Coriolis Effect affects ocean surface currents. The
Coriolis Effect acts on moving water, because it is not
attached to the rotating Earth. As water flows over the
rotating earth, it appears to deflect to the right in the
Northern Hemisphere and the left in the Southern.
The deep water that surfaces in upwelling is cold; by
looking at Sea Surface Temperature maps we can
identify cool upwelled water versus hotter surface
water.
Upwelled water also contains nutrients (nitrate,
phosphate, silicate) and dissolved gases (oxygen and
carbon dioxide) that are not utilized at depth because of
a lack of sunlight.
Now on the surface, these nutrients and gases help to
fuel photosynthesis by small algae called
phytoplankton.
Phytoplankton photosynthesize using specialized color
pigments called chlorophyll. Thus, “Ocean Color” maps
are another way to identify areas of upwelling. Where
on this ocean color map are high phytoplankton
concentrations?
Ecological and Economic effects of
upwelling:



Upwelling leads to more
phytoplankton
More phytoplankton leads to more
fish
More fish lead to commercial fishing
jobs and to more seafood
Even though upwelling areas account for
only 1% of the ocean surface, they
support 50% of the worlds fisheries.
Phytoplankton come in many shapes and
forms. Collectively they form the base of
oceanic food webs.
Without upwelling many of the
world’s fisheries would not thrive.
Some climatic events can reduce
upwellings.
~
El Nino
Along Peru’s coast, an El Nino event decreases the coastal
winds. Thus the upwelling from below is slowed.
An El Nino condition results from weakened trade winds in the western Pacific
Ocean near Indonesia, allowing piled-up warm water to flow toward South America.
What is La Niña?

La Niña is characterized by
unusually cold ocean temperatures
in the Equatorial Pacific, compared
to El Niño, which is characterized by
unusually warm ocean temperatures
in the Equatorial Pacific.
VII. Waves and Wave Action
A. Causes – wind and earthquakes
B. Characteristics of Waves
1. crest – highest point of a wave
2. trough – lowest point of a wave
3. wavelength – distance between 2
adjacent wave crests or wave troughs
4. wave frequency – the number of
waves that pass a point in a certain
amount of time
5. wave period – time between the
passage of two wave crests(or troughs)
at a fixed point
6. wave height – vertical distance between
crest and trough of a wave
7. breaker – high wave crest that has been
pulled down by gravity
8. surf – area between the breaker zone
and the shore
9. white caps – wave crests breaking into
white foam
10. swells – formation of long wavelength
surface waves more stable than normal wind
waves and formed by storms
11. deep water waves – waves that move in
water deeper than ½ their wavelength
12. shallow water waves – waves that reach
water shallower than ½ their wave height
C. Tsunami – a great sea wave caused
especially by undersea earth movement
or volcanic eruption
D. Storm surge – an offshore rise of water
often associated with a low pressure
weather system, typically tropical
cyclones
E. Undertow – the current beneath the
surface that sets seaward or along the
beach when waves are breaking on the
shore
F. Longshore current – an ocean current
that moves parallel to the shore
VIII. Tides
Tidal range – the vertical difference between
high and low tides
1. high tides – occur twice a day, when the
ocean water bulges as a result of the
gravitational pull of the overhead moon
2. low tides – occur twice a day, when the two
areas of the earth are not experiencing high
tide
B. Spring Tide – exceptionally high and low tides
that occur at the time of the full and new
moons, when the sun, earth, and moon are
approximately aligned
C. Neap Tide – times when the difference
between high and low tide are minimized.
Occur during quarter moons
A.
IX. At the shoreline
 Water
becomes shallow, wave height
increases because wave length
decreases
 Waves become steeper, then collapse
(breakers)
Wave refraction
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Close to coast,
water gets more
shallow
Waves are slowed
down
If waves arrive at
an angle, one part
is slower than the
rest
Causes waves to
bend = wave
refraction
 Waves
arriving at bays are slow
(deposition)
 At headlands, faster (erosion)
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A sequence of
features is
produced as
headlands are
degraded
Sea cliffs
Waves erode
base undercutting
• Headlands
may be eroded
back leaving a
remnant (stack)
Longshore drift
 Waves
arrive at a
coast at an angle
(swash)
 Backwash returns
at 90 degrees
Sand is moved along the beach = longshore
drift or longshore current
Coastal deposition
 Result
of
longshore
drift and a lot
of sediment
 = produces
extensions of
deposit from
the shoreline
spit = curved extension
 May
grow
across a bay
(baymouth
bar)
 May link an
island to the
main land
(tombolo)
Types of Coastline
Submergence and emergence changes
coastlines
Pocket beaches
Emergent coast
 Uplifted
land surface
 Coastal landforms are found above
present sea level
a wave-cut
platform when
elevated uplifted marine
terrace
Barrier Island Coasts
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Occur on low lying
coasts with gentle
gradients
BARRIER ISLANDS low ridges of sand built
by waves
 behind the islands
are lagoons
 shallow water with
tidal deposits
TIDAL INLETS - gaps
between the islands