Cool Facts 71% of all water on Earth is in our oceans. Average depth of the oceans is 2.65 miles deep! Deepest point in the ocean is about 7 miles deep!
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Cool Facts 71% of all water on Earth is in our oceans. Average
depth of the oceans is 2.65 miles deep! Deepest point in the ocean
is about 7 miles deep! Pressure increases as you go down in the
ocean. Until 2000, there were only 4 oceans.
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Oceanography The study of Earths oceans Did not begin to study
until 1800s with the Challenger Challenger: first research ship
Investigated ocean currents, temperature, and chemical composition
of the ocean
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Advanced Technology SONAR: SOund NAvigation and Ranging
Submarines to investigate deep ocean trenches
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Scientists use SONAR to map seafloor and NOW can use it to
understand aquatic life! http://www.youtube.com/watc
h?v=-fAAxEIFeLU
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Origin of Oceans Earths water may have originated from Comets
or through volcanism. Comets: carried water, collided with Earth,
then released the water Volcanoes: during eruptions, water vapor
and carbon dioxide released, condensed, and formed Earths early
atmosphere
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The Major Oceans (5) 1. Pacific 2. Atlantic 3. Indian 4.
Southern 5. Arctic
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Pacific Largest Contains deepest point on earth! (7 miles
deep-Marianas Trench) Covers ~35% of the Earth Between Asia and
NA/SA
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Atlantic Next to NC! Deepest Point: Puerto Rico Trench Second
largest Covers ~21% of Earth
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Indian Deepest Point: Java Trench Near India-Africa on East and
Asia on North Covers ~15% of Earth
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Southern Ocean established in year 2000! Newest ocean Surrounds
Antarctica Covers the South Pole
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Arctic Smallest ocean Deepest Point: Arctic Basin Covers North
Pole Often completely frozen during the winter
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Sea Level Level of the oceans surfaces Can change in response
to the melting of ice during warm periods and/or expanding of
glaciers during ice ages Average sea level is rising at a rate of 1
to 2 millimeters per year because glaciers are melting (indicates a
warm period)
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Composition of Ocean Water 96.5% pure water and 3.5% salts
Salinity: total amount of solid material (salts) dissolved in water
Salinity measured in parts per thousand (ppt).
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Where does the salt come from? Salt = NaCl = the salt you put
on food! Comes from erosion Salinity can decrease by precipitation,
runoff from land, melting of ice (all adding more freshwater)
Salinity can be increased by evaporation (only the water
evaporates, not the salt) and by sea water freezing (only the water
freezes, not the salt)
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Why are our oceans salty? Salinity affects density! We need
changes in density so we can have ocean currents (we will study
this in a few days) So what makes our water MORE dense? Less salt
or More salt?
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Profile of an Ocean Ocean water is warmer at the surface
because of the sun. Temperature decreases with depth. Thermocline:
zone in ocean where there is rapid temperature change.
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Density and how it relates to temperature. Colder water is more
densemeans it will be below warm water. Because of this, there are
3 zones: Surface zone: at top Transition zone: in middle (includes
thermocline) Deep zone: at bottom. Sunlight never reaches this
section. 80% of ocean water found here.
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Surface Zone Transition Zone Deep Zone
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Ocean Movements Ocean water moves in 3 ways: Waves Currents
Tides
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Waves The movement that carries energy through the water Most
waves are caused by wind moving over the waters surface.
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Anatomy of a Wave Crest: top of the wave Trough: bottom of the
wave Wave height: vertical distance between the trough and the
crest Wave length: horizontal distance between two crests or
troughs.
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Ocean Currents Masses of ocean water that flow from one place
to another
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2 types of currents 1. Density currents: vertical currents that
result from different densities of water. Denser water sinks. 2.
Surface currents: movements of water that flow horizontally in the
upper part of the oceans surface-usually because of wind.
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What ultimately fuels the currents? THE SUN Warms waters on
surface-makes them less dense Causes evaporation-makes water more
salty and therefore more dense
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Tides Periodic rise and fall of sea level Caused by
gravitational attraction between the earth and moon. Side of the
earth facing the moon and opposite the moon experience tides.
Usually 2 high and 2 low tides a day
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Spring Tide When the earth, moon, and sun are all lined up.
This creates higher, high tides and lower, low tides. Occurs at
full and new moons.
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Neap Tide During a first or third quarter moon, when the moon
is at a right angle to the earth. Results in lower, high tides and
higher, low tides.
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Tidal range Difference in height between successive high and
low tides. If high tide is 4 meters and low tide is 1 meter, what
is the tidal range?
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Tidal Patterns Diurnal tides: a single high tide and a single
low tide each day Semidiurnal tides: two high tides and two low
tides each day Mixed tides: two high and two low a day but the the
heights are different between the two high and two low