IGCSE Marine section 1.3 Oceans and seas

The syllabus lists these goals:

index can be found here
Identify the Earth’s oceans as the Arctic,Atlantic, Pacific, Indian and Southern
 

Identify and describe the location of oceans and other features on maps, diagrams and other images

Explain that oceans are interconnected and encircle the Earth as a World Ocean

Describe the extent and depth of the oceans

Describe seas as smaller areas of water, sometimes within oceans, often partially
enclosed by land, e.g. the Bering Sea in the Pacific Ocean and the Mediterranean Sea

Describe, and identify from maps, diagrams and other images, the geomorphology of the
oceans

limited to:
(a) continental shelf
(b) continental slope
(c) abyssal plain
(d) mid-ocean ridge
(e) ocean trench
(f) volcanic island

Seas and ocean covers 71%, and are all connected into one big world ocean-

Most of the water on earth is salt water in the oceans, fresh water is only a few percent

Oceans are bigger than seas.We have the 5 main oceans, and many seas. Seas are way more affected by land than oceans are.

For locations, we use a coordinate system. The middle horisontal line is the equator. As we move north, the lattitude increases until we reaches 90 degrees north at the northpole.

Longitude lines go the other way (from north to south) and the middle line here goes trough Greenwitch in England.

The tropical zone goes from 23.5 degrees north to 23 degrees south.

The polar regions start at 66.5 degrees north and south

Movement of tectonic plates  causes the geomorthology of the ocean, as seen below

The different features can be defined as:

Continental shelf:

Part of the continental plate extending from the coast in shallow waters, with little or no slope. Caused by sedinents from erosion from the land.

Continental slope:

The steeper slope from the shelf to near the abbysal plain. The edge of the continental crust, where this means ocean crust

Mid ocean ridges:

Underwater mountain ridges, found where tectonic plates are moving apart. Mid atlantic is the most massive.

Abbysal Plain 

Flat ocean floor,  caused by spreading of tectonic plates. Large flat ecosystem between 3000 to 6000 meters below

Ocean trenches; 

 Deep depressions, caused at a convergent plate boundaries.  The deepest is the Mariner trench at about 11.000 meters below surface.

Volcanic Islands: 

Volcanos that erupt and cause islands to rise from the seabottom

This is the AS version of the syllabus:

Optional videos on seafloor spreading:

Crash course also have a good video here, that shows the process that shapes the earth (not only in the ocean)