Chapter 5

Question 1

Describe the Eckman Spiral.

Answer 1

Earths rotation and friction:
Current moves to right of the wind Northern Hemisphere: Because of friction, current deflects more to the right with increasing depth.

Question 2

What direction is the net water movement in the Northern Hemisphere? (angle, and direction) In the Southern Hemisphere? See Figure 5.5.

Answer 2

90 degrees to the right

90 degrees to the left

Question 3

What is the controlling force behind surface currents?

Answer 3

Wind

Question 4

Equatorial Currents

Answer 4

North Equatorial Current–Flows West (traced in red)–Located North of Equator–Normally Strong current•

South Equatorial Current–Flows West (traced in red)–Located South of Equator–Normally Strong

Question 5

Equatorial Counter Currents

Answer 5

Located between North and South Equatorial Currents–Flows East (traced in red)–Normally weak–Strengthens during El Nino event

Question 6

West Boundary Currents

Answer 6

Located on West side of Oceans•Carry warm water from the equator to the Poles (traced in red)•Flows North in the Northern Hemisphere and South in the Southern Hemisphere•Strong Currents

Question 7

Eastern Boundary Currents

Answer 7

Located on East side of Oceans•Carry cold water from the poles to Equator (traced in red)•Flows South in Northern Hemisphere and North in Southern Hemisphere

Question 8

What is up-welling?

Answer 8

•Cold, Nutrient-rich water rises to surface•Occurs when current moves away from coastline or when currents diverge•High bioproductivity-lots of life

Question 9

What is downwelling?

Answer 9

•Warm, Nutrient-poor water sinks to depths•Occurs when current moves toward coastline or when currents converge•Low Bioproductivity-little life

Question 10

Which (upwelling or downwelling) reduces biological productivity?

Answer 10

Downwelling

Question 11

What is Pycnocline

Answer 11

Pycnocline-density increases rapidly with depth

Question 12

What is thermocline

Answer 12

temperature decreases rapidly

Question 13

Halocline

Answer 13

Salinity increases rapidly

Question 14

What is thermohaline circulation?

Answer 14

•Deep water currents•Below the pycnocline•Result of density differences in the water•Much slower than surface currents

Question 15

What is the driving force in thermohaline circulation?

Answer 15

Density differences in the water

Question 16

What is the relationship between the pycnocline and the thermocline?

Answer 16

Both the pycnocline and thermocline have the same depth of 500 to 1000 m deep

Question 17

What is the relationship between the pycnocline and the halocline?

Answer 17

Both the pycnocline and halocline have the same depth of 500 to 1000 m deep.

Question 18

Why is there not a pycnocline near the poles? Hint: Think about temperature.

Answer 18

The water at the poles is nearly the same temperature regardless of depth. Therefore the density does not change with depth.

Question 19

Describe the vertical structure of the ocean in middle latitudes based on the variation in temperature with increasing depth.

Answer 19

At middle latitudes-there is a mixed layer at the surface where temperature varies seasonally. This is where the surface currents are located. Then there is a pycnocline that develops because of a thermocline (temperature decreases with depth to 4°C). Below the pycnocline is a mixed layer where density and temperature are relatively constant. This deep layer is where the thermohaline currents are located.

Question 20

Why is the thermocline different in summer versus winter?

Answer 20

In summer, the higher sun angles allow sunlight to penetrate deeper into seawater. This warms the water to a greater depth, thus a seasonal thermocline develops above the deep thermocline.In winter, the lower sun angles and higher albedo allow for less sunlight to penetrate seawater, thus the surface is colder. There is only a mixed layer and a deep thermocline (no seasonal thermocline)

Question 21

Water sinks at high latitudes

Answer 21

cold water results in high density

Question 22

So-what keeps the Equator from becoming hotter and hotter year after year and the poles colder and colder?

Answer 22

Global winds, Ocean Currents, and storm systems all contribute to mixing and spread the heat around