The Ocean Floor THE VAST WORLD OCEAN

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1 OCEANOGRAPHY Name Color all water LIGHT BLUE. Color all land LIGHT GREEN. Label the 5 Oceans: Pacific, Atlantic, Indian, Arctic, Antarctic. Label the 7 Continents: N.America, S.America, Europe, Asia, Africa, Australia, Antarctica. Label North, South, East, and West. Draw & Label the Equator (0 latitude), Prime Meridian (0 longitude), and the International Date Line (180 longitude). Draw & Label the Mid-Atlantic Ocean Ridge and the Mariana Trench. Label the Bering Strait, Red Sea, Baltic Sea, North Sea, Gulf of Mexico, and Mediterranean Sea.

2 The Ocean Floor THE VAST WORLD OCEAN ORIGIN OF THE OCEANS How old is the Earth? Where did the water come from? o Comets and Meteorites: o Volcanism: volcanic gas has mostly and The CO 2 and other gases formed the Earth's As the Earth cooled, the water vapor, forming the oceans. THE BLUE PLANET Earth is known as the " " because ~ % of it is covered by oceans. o Average Depth of the Oceans: m ( km) o Where is most of the water - Northern or Southern Hemisphere? o All oceans are really one big body of water. o % of the water on earth is found in the oceans. Only % is freshwater. o OCEANOGRAPHY: Sea Level = o Sea Level has risen and fallen by hundreds of meters due to the Ice Caps (H 2 O level ) & Glaciers (H 2 O level ) o Sea Level is also affected by tectonics. TECTONICS = Tectonics can change the level of the seafloor, thus changing o Currently, sea level is 1-2mm/year due to GEOGRAPHY OF THE OCEANS There are 4 major OCEANS: o,,, & o Largest =, Smallest = Sea Ice: Ice is ( more / less ) dense than water, so it floats. SEAS = o All seas and oceans belong to one global ocean, whose waters are thoroughly mixed.

3 MAPPING THE OCEAN FLOOR The topography of the ocean floor is as diverse as that of the continents. Bathymetry = measurement of the ocean floor (bathos =, metry = ) Began with the ship " " in the 's o Although today s technology is much more sophisticated!! was first used in the 1920s to the seafloor features of the S. Atlantic Ocean. SONAR = o How does it work? o See page 398 in textbook. o Velocity of sound in water: m/s o Equation: (Time for echo return) X (Velocity of sound in water) 2 o Problem: It takes 4 seconds for an echo to return. How deep is the ocean? o SIDE-SCAN SONAR = o It is used to SATELLITES continually gather information about the ocean floor. o Data has shown that the ocean surface is not totally flat o Why?? SUBMERSIBLES (small underwater crafts) give us much data. o Manned crafts: Trieste Jacques Piccard (1960) went to the (10,912 m) Alvin 4000 m Sea Cliff II 6000 m o Unmanned crafts: called AUVs ( )

4 Ocean Water and Ocean Life THE COMPOSITION OF SEAWATER SALINITY Salinity:. Seawater is about % water and % dissolved salts. Expressed as of salt per of water (or parts per thousand ) Average salinity: ppt ( %) Most abundant salt in seawater: Seawater also has dissolved and Sources of Sea Salts: Processes Affecting Salinity: water decreases salinity: water increases salinity: o How does salinity increase when sea ice forms? OCEAN TEMPERATURE VARIATION Surface Layer Temperatures: Varies with the amount of received, which is a function of. Middle latitudes (near the ) have higher temperatures, and vice versa. Temperature Variation with Depth: o water is denser than water, so cold water will. Deeper = Colder! o Three temperature layers: Surface layer: Thermocline: (300m-1000m) It creates a Bottom layer: o In polar regions, the surface layer & thermocline don't exist because OCEAN DENSITY VARIATION Density varies with depth due to both and. Denser Water = ( colder or warmer ) and ( salty or fresh ) why floating is easier in the ocean!

5 The Dynamic Ocean OCEAN CIRCULATION & WAVES AND TIDES 4 Movements of the Ocean: Waves, Tides, Currents & Upwellings WAVES = Generated mainly by o As a wave passes, water moves in a, returning to its original position. o The water doesn't move forward, only the. Wave Measurements: o Highest point =. Lowest point =. o Distance from Crest to Trough =. o Distance from Crest to Crest (or trough to trough) =. o Wave speed with wavelength. Breaking Waves: o As waves reach the shallow water near a shoreline, energy is due to against the seafloor. This the wave. o Incoming wave crests catch up with slower crests, decreasing the. o Waves get higher, steeper, and unstable, causing the crests to. o Collapsing wave crests =. TIDES = High Tide = Low Tide = Tidal Cycles (High Tide Low Tide High Tide) usually = o Diurnal: o Semidiurnal: o Mixed:

6 Causes of Tides: o Gravitational Pull of the and the o Spring Tide = o Neap Tide = o Which is bigger - Solar or Lunar Tides? Why? OCEAN CURRENTS CURRENT = o Density Current = controlled by. Move very. o Surface Current = controlled by. Move very. Only affect the deflect some currents so that they join other currents, causing a circular current, called a. o 5 Major Gyres: North & South Pacific, North & South Atlantic, and Indian Ocean o In the Northern Hemisphere, the gyres circulate in a direction. o In the Southern Hemisphere, the gyres circulate. Currents flow near the equator. When they hit land, they are deflected toward the. This carries warm water to colder regions of the world. When it gets to the polar regions, the water and is deflected back toward the on the other side of the ocean. UPWELLING Water not only moves horizontally (currents) but it also moves. UPWELLING = Cold water flows upward to replace warm surface water blown out to sea by offshore winds. They mainly occur on coasts. Rich in, thus supporting lots of marine life.

7 Currents & Gyres Color all water LIGHT BLUE. Color all land LIGHT GREEN. Label the following in color (red = warm current, blue = cold current): See Page 449 Gulf Stream, North Atlantic Current, Canary Current, North Equatorial Current, South Equatorial Current, Brazil Current, Benguela Current, California Current, North Pacific Current, Kuroshio Current, East Australian Current, Peru Current, West Wind Drift, W.Australian Current, Agulhas Current Draw and Label the 5 Major Gyres.