The Structure Of The World Ocean

Question 1

What is an ocean?

Answer 1

• body of saline water covering the earth
• belongs to the hydrospher, containing more than 97% of it
• is conventionally subdivided into five major oceans:
  Pacific, Atlantic, Indian, Arctic, Southern (Antarctic)

Question 2

What is a sea?

Answer 2

• body of saline water associated with one of the five oceans
• strictly speaking: partly or fully enclosed by land
• types of seas:
  Marginal seas (Randmeer), Mediterranean seas, regional seas, epieric (inland) seas

Question 3

Difference between continental shelf and slope

Answer 3

• continental shelf is shallow and still belongs to the continent crust
• continental slope plunges steeply into the abyss, is the boundary between continent crust and oceanic crust

Question 4

Why is a detailed mapping of the ocean floor essential?

Answer 4

• to guarantee safety of ships
• exploration/exploitation of resources
• more accurate climate models (e.g. tsunamis)
• safety and understanding of ocean life (e.g. aquatic animals)

Question 5

Which ways are used to map the ocean floor?

Answer 5

• satellites analyse density of solid land > depth
• ecosystems in ships > sent soundwaves to ground (depth/profile)
• vessels > work automatically and scan the ocean

Question 6

Vertical structure

Answer 6

• shown with the help of the hypsographic curve
  > hypsography: study of distribution of elevation on the surface of the earth
• Land > 29,2%; ocean 70,8%
• average elevation of land > 840m; average depth of ocean > 3.000-4.000m
• highest point: Mount Everest > 8.848m
• lowest point: Marian trench > 11.022m

Question 7

Parts of the ocean floor

Answer 7

1. Continent / seashore
2. Continental shelf
3. Continental slope
4. Mid-ocean ridge (underwater Mountain range created by divergent plate movement)
5. Abyssal plain (ocean floor)
6. Island arc + volcanic Island
7. trench (a long, narrow ditch)
8. Submarine canyon (V shaped valleys in the continental slope; created by falling ocean waters)

Question 8

What is a rip current?

Answer 8

• found in ocean shelf
• strong current between 2 sandbanks that pulls you back into the ocean
• swim to the side to one of the sandbanks
  > current too strong to swim against it

Question 9

Why can the mapping of the ocean floor be considered a two-edged sword?

Answer 9

• on one hand we want to understand the species for scientific reasons
• on the other hand will we use the knowledge to exploit the ocean and use it for our own gain

Question 10

How could both sides (of the two-edged sword) benefit from the mapping of the ocean?

Answer 10

• go hand in hand:
  • explore fishing regions > limit number of exploitation
  • resources > share with other countries > no Nations have to suffer
  => maybe find common ground