Saltwater Systems

1
Saltwater Systems

• oceans seas cover 75 of the Earths surface
• and contain 97 of the worlds water
• ocean water is saline, with about 3 salt
• salinity is the amount of dissolved salt in
  liquid
• seas are smaller than oceans and tend to be
  surrounded by land

2
The worlds oceans can be divided into 5 regions
3
Ocean Basins

• ocean basins are huge!
• they have mountains, valleys and vast plains
• they are formed mainly from movement of tectonic
  plates
• as they move apart ocean basins expand
• as they move together ocean basins shrink
• the average depth of the oceans is 4,000 m
• the deepest place is Marianas Trench at about
  11,000 m

4

• where plates pull apart magma can come to the
  surface and create mountains or ridges (e.g.
  Hawaiian Islands)
• where one plate slides under another a trench is
  often formed (e.g. Marianas Trench)

5
The ocean basin does not begin at the shoreline
it begins at the lower edge of the continental
slope.
6
Ocean Temperature and Depth
The Sunlight Zone
The Twilight Zone
The Midnight Zone
The Abyss
7
Ocean Waves
Energy Direction
8
When Waves Hit Shore
Energy Direction
The wave collapses onshore in a tumble of water
called a breaker.
9
Changing Shorelines
10
Tides

• tides are regular cycles where ocean water levels
  rise and fall
• they are caused by the moons ( suns)
  gravitational pull on the water
• the moon rotates around the Earth and so its
  distance from oceans changes in 24 hours
• when the moon is closest to the ocean it will
  have high tide
• when the moon is farthest from the ocean it will
  have low tide

11

• spring tides are the biggest variation between
  high low tide
• very high when the moon sun line up on the same
  side of the Earth and pulling together
• very low when the moon sun are on opposite
  sides of the Earth and pulling in opposite
  directions
• neap tides are the smallest variation between
  high low tide
• moons gravitational pull is at right angles to
  the gravitational pull of the sun

12
Ocean Currents5 major gyres
North Atlantic
North Pacific
South Pacific
Indian Ocean
South Atlantic
13
The Gulf Stream
14
(No Transcript)