Unit 3.2: The World's Five Oceans

Question 1

The worlds 5 oceans cover what percentage of earths surface? What percentage of the biosphere does it have?

Answer 1

Covers over 70% of earths surface and contains 99% of the earths biosphere.

Question 2

What are the 5 oceans and what percentage of total ocean do they have?

Answer 2

1. Pacific: 46%
2. Atlantic: 25%
3. Indian: 20%
4. Southern: 6%
5. Arctic: 3%

Question 3

What is the difference between these bodies of water that all contain salt water?

1. ocean
2. sea
3. bay
4. gulf
5. sound
6. strait

Answer 3

1. Ocean: very large expanse of water that is composed of salt water.
2. Sea: Large body of salt water bounded by land masses
3. Bay: Inland sea with relatively calm surfaces. Land surrounds it on 3 sides.
4. Gulf: Larger than a bay, land on all 3 sides
   5: Sound: Long body of deep water that usually connects two bodies of water.
5. Strait: Narrow passage connecting 2 bodies of water.

Question 4

What are the 5 different properties of the ocean?

Answer 4

1. Light penetration: Measure of how deep in water column light can penetrate. Shortwave can penetrate the deepest.
2. Water pressure: water pressure increases the deeper in the water column you go. Increases by 1kg/cm^2 for each 10 m of depth. This is also known as a BAR.
3. Salinity: The concentration of dissolved minerals in the sea water. Average is about 3.5% but can vary between 1 and 4%
4. Halocline: The transitional zone of salinity that changes between the ocean surface and the deep sea.
5. Ocean Acidity: results from absorbing carbon dioxide. More absorption means greater acidity which means pH decreases.

Question 5

What causes salinity to vary spatially?

Answer 5

Evaporation and river discharge depending on the area.

Question 6

What are the various temperature layers in the ocean?

Answer 6

1. Typically water on top is warmer due to light penetration.
2. thermocline: transitional zone of temperature change (varies based on season and latitude)
3. varies but this last layer is at 2500m everywhere and the temp is between 0 and 2oC.

Question 7

What are the various vertical ocean layers based on properties of sea water?

Answer 7

1. Epipeplagic zone: Topmost layer, absorbs 99% of sunlight.
2. Mesopelagic zone: between 200 & 1000m, very little sunlight.
3. Bathypelagic zone: between 1000 & 4000m, no light, found along the continental slope.
4. Abyssopelagic zone: between 4000 & 6000m flat topography, also known as the abyssal plains. Starts where the continental slope ends.
5. Hadal zone: between 6000 & 10,000m deepest part and the location of the deep sea trenches.

Question 8

What are the features of the ocean bottom?

Answer 8

1. Continental shelves: the shallow area around large land masses. Geologically part of the continental crust that is submerged underwater.
2. Abyssal Plains: Flat submarine plain located on deep ocean floor. Located between continental shelves and ocean ridges. (deeper than 3000m)
3. Mid-Oceanic ridge: Large underwater mountain or elevated area. Divides the large ocean basins. Restricts mixing of water masses at the bottom of the ocean.
4. Seamounts: Isolated, flat-topped inactive volcanoes that once protruded above sea-level.
5. Deep-sea trenches: Long, narrow valleys on sea floor, the deepest part of the ocean.

Question 9

What is are gyres?

Answer 9

Large scale circulation system of ocean currents that rotate in a clockwise direction (right) in the northern hemisphere. Due to the Coriolis force.

Question 10

What are ocean currents?

Answer 10

Large scale, continuous movement of seawater in a consistent pattern.

Question 11

What are the 2 types of currents? What causes the differences?

Answer 11

1. Surface currents: It is the movement of large scale oceanic water due to atmospheric winds.
2. Deep ocean currents: Currents below surface, driven by density differences between locations. Like the pressure gradient force.