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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
II. Properties of Ocean 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.
II. Properties of Ocean 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
III. Oceans
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 example- protists,
crustaceans
IV. Life in the Ocean
B. Nekton – organisms that swim
in the ocean freely.
examples – larger fish, squid,
sea turtles, whales
IV. Life in the Ocean
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



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
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.
Coral Reefs
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.
Polar Ecosystem
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 Arctic
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.
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 upwelling, 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.
http://www.classzone.com/books/earth_science/terc/content/visualizations/es19
04/es1904page01.cfm
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.
VI. Instruments of Investigation
A.
B.
SCUBA – Self-Contained Underwater
Breathing Apparatus. Tanks of
compressed air strapped on a diver’s
back and connected by hoses to a
mouthpiece for breathing
SONAR – Sound Navigation And Radar.
Methods of mapping the ocean floor by
transmission and reflection of sound
waves
Instruments of Investigation (cont.)
C. Geostationary operational
Environmental Satellites (GOES)
orbit the Earth at 22,000 miles.
They are highly advanced
observation platforms supplying
detailed imagery of the Earth’s
oceans
Instruments of Investigation (cont.)
D. Underwater Laboratories – The
Aquarius Underwater Laboratory is
the only undersea laboratory
dedicated to marine science
operating in the world. Aquarius
provides life support systems that
allow scientists to live and work
underwater, in reasonably
comfortable living quarters, with
sophisticated research capabilities
Instruments of Investigation (cont.)
E. Deep ocean submersibles – Over the
last few decades, engineers have
developed technologies capable of
meeting the many challenges that the
deep sea imposes upon explorers.
VIII. 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
VIII. Waves and Wave Action
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
VIII. Waves and Wave Action
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
VIII. Waves and Wave Action
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
VIII. Waves and Wave Action
C. Tsunami – a great sea wave caused
especially by undersea earth movement
or volcanic eruption
VIII. Waves and Wave Action
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
move parallel to the shore
IX. Tides
A. 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
IX. Tides
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
X. Currents and Climates
A. Surface currents – Horizontal movement of
seawater in the ocean
1. are driven by winds and can affect
movement to a depth of several hundred
meters
2. either cool or warm the air above it
influencing the climate of the land near the
coast (example – Gulf Stream)
B. Ocean Currents
Deep Currents
At the shoreline
 Water
becomes shallow, wave height
increases because wave length
decreases
 Waves become steeper, then collapse
(breakers)
Wave refraction




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)



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



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
Oceanography – Think about it!
You will be given a scenario which you
will read. You will then:
1. Draw a ‘before’ picture with color
what your area might look like.
2. Draw an ‘after’ picture with color
what your area might look like.
3. Answer the seven questions on a
separate sheet of paper.
DO NOT WRITE ON
‘OCEANOGRAPHY – THINK
ABOUT IT!’ PAPER