homeI. World's oceans
A. Three major oceans
1. Pacific
a. Largest
b. Deepest
2. Atlantic
a. Second largest
b. Not as deep
3. Indian
a. Smaller than the Atlantic
b. Deeper than the Atlantic
B. Smaller bodies of water
1. Mediterranean Sea
2. Black Sea
3. Arctic Ocean
C. Sources of fresh water
1. Rivers and streams
2. Lakes and ponds
II. Properties of ocean water
A. Chemical makeup
1. Gases
2. Solids
3. Pure water
B. Salts in ocean water
1. Sodium chloride most abundant
2. Salinity expressed in parts per thousand
C. Sources of salt
1. Volcanoes
2. Land erosion
D. Gases in ocean water
1. Most abundant
a. Nitrogen
b. Carbon dioxide
c. Oxygen
2. Amount varies with depth
3. Amount of dissolved gases affected by temperature
E. Temperature of ocean water
1. Sun major heat source
2. Three different zones
a. Surface zone
1.) Water mixed by waves and currents
2.) Temperature remains constant
b. Thermocline (transition zone)
1.) Temperature drops rapidly
2.) Does not occur at specific depth
3.) Warm water does not mix with cold
c. Deep zone
1.) Extremely cold
2.) Temperature decreases slightly
III. Ocean floor
A. Topography different from continents
B. Edges of continent
1. Shoreline
a. Where land and ocean meet
b. Marks position of sea level
2. Continental margin
a. Underwater edge of continent
b. Forms part of ocean floor
c. Consists of 3 parts
1.) Continental shelf
2.) Continental slope
3.) Continental rise
C. Features of ocean floor
1. Abyssal plains
a. Large flat areas
b. Consist of thick layers of mud, sand, silt
2. Seamounts and guyots
a. Underwater volcanic mountains
b. More in Pacific Ocean
c. May reach above ocean surface
d. Guyots are flat-topped seamounts
3. Trenches
a. Deepest parts of ocean
b. More trenches in Pacific Ocean
c. Challenger Deep - deepest spot on Earth
4. Midocean ridges
a. Underwater mountain ranges
b. Areas where molten rock forms new crust
c. Rift valleys run along the middle
5. Reefs
a. Found only in tropical waters
b. Limestone structures called coral reefs
c. Need sunlight to make skeletons
d. 3 types of coral reefs
1.) Fringing reefs, touch shoreline of island
2.) Barrier reefs, separated from shore by lagoon
3.) Atoll, surrounds island that is beneath the surface
IV. Ocean life zones
A. Factors affecting life
1. Amount of sunlight
2. Temperature of water
3. Water pressure
B. Three major groups of plants and animals
1. Plankton
a. Largest group
b. Float near surface
2. Nekton
a. Ocean life that swims
b. Found at all levels of ocean
3. Benthos
a. Live on ocean floor
b. Some are plants in shallow water, some are animals
C. Intertidal zone
1. Region between high and low tide lines
2. Changeable area
D. Neritic zone
1. Low tide line to edge of continental shelf
2. Receives plenty of sunlight
3. Richer in life than any other zone, big source of food
E. Open-ocean zones
1. Bathyal zone
a. Begins at edge of continental shelf
b. Extends down 2,000 meters
c. Receives little sunlight at bottom of zone
2. Abyssal zone
a. Extends down from 2,00 meters to 6,000 meters
b. Receives no sunlight
c. Little available food
d. Water pressure high
V. Mapping ocean floor
A. Challenger
1. First to explore the ocean floor
2. Wire used to measure ocean depth
B. Oceanographers
1. Use modern instruments
2. Goal to map ocean floor using indirect methods
a. Echo-sounding equipment
b. Sonar
c. Radar
d. Submersibles
e. Satellite - Seasat 1978
VI. Motions of oceans
A. Waves
1. Pulses of energy
2. Set in motion by wind, earthquakes, gravitational pull of moon
3. Height of wave determined by
a. Wind speed
b. Length of time wind blows
c. Distance wind blows
4. Characteristics of waves
a. Crest (highest point)
b. Trough (lowest point)
c. Wavelength
d. Wave period, time to pass a given point
e. Wave frequency, number of waves to pass given point
f. Undertow, retreating water
5. Tsunamis
a. Caused by underwater earthquake
b. Highest ocean wave
c. Hugh amount of energy
B. Currents
1. Surface currents
a. Caused by wind currents
b. Build up sand bars
c. Rip current, type of undertow
2. Deep currents
a. Caused by differences in density of water
b. Flow in opposite direction of surface current
c. Upwelling, rising of deep cold currents
C. Tides
1. Caused by gravitational pull of moon
2. Two types
a. High tide
b. Low tide
