Ch 6b: Hydrosphere (Oceans)

Question 1

Oceans cover:

Answer 1

71% of Earth’s surface, uneven distribution.

Question 2

Max depth of the ocean, average depth, volume of water

Answer 2

11km, 4.5km, 1.35x10^18

Question 3

Ocean structure

Answer 3

Changing layers: fresh water influx, ocean size, more land exposure. Temperature, salinity, density

Question 4

Ocean layer changes are more

Answer 4

noticeable at the surface and near coastlines.

Question 5

Ocean water properties: Density

Answer 5

Variable and Temperature dependent, pycnocline.

Question 6

Ocean water properties: Salinity

Answer 6

varies from 32-37%. Increases with depth, salinity is high where evaporation is high. Low where river water enters ocean

Question 7

Temperature and Salinity with Depth

Answer 7

saline water is denser sinks

Question 8

Halocline:

Answer 8

is region of rapid salinity change

Question 9

Thermocline:

Answer 9

is zone of rapid temperature change

Question 10

Ocean Temperature:

Answer 10

surface varies from 0 to 28degrees, still remains above 0 at depth. Lowest is 0.4 as salt doesn’t allow the water to freeze.

Question 11

Ocean composition

Answer 11

relatively constant, proportions do not change but the amounts can change. Species maintain

Question 12

Ocean movement: surface currents

Answer 12

Wind driven surface currents, 10% by volume. Caused by atmospheric circulation and Earth’s rotation. Affects upper 100m

Question 13

Large scale movement: subsurface

Answer 13

Density driven subsurface currents, 90% by volume. Drives the thermohaline circulation

Question 14

ENSO

Answer 14

El Nino -southern oscillation, occurs in the pacific ocean. Extreme ends are termed El Nino and La Nina

Question 15

La Nina

Answer 15

lower pacific ocean temperature than normal

Question 16

El Nino

Answer 16

higher pacific ocean temperature than normal

Question 17

Coriolis Effect

Answer 17

Objects moving in a straight line appear to curve relative to observer on solid Earth

Question 18

Coriolis Effect: Rotates about its vertical axis

Answer 18

CCW in Northern Hemisphere,

CW in Southern Hemisphere

Question 19

Ekman Effect

Answer 19

Coriolis deflects wind driven currents in Northern hemisphere. Slightly CW of actual wind direction, deeper currents are progressively rotated CW. Overall average water movement is 90degrees CW of wind

Question 20

Ekman Transport: Upwelling occurs…

Answer 20

where Ekman Transport is offshore

Question 21

Ekman Transport: Downwelling occurs…

Answer 21

where Ekman transport is onshore

Question 22

Geological Aspects

Answer 22

dominated by plate tectonics, sedimentation

Question 23

Continental Margins

Answer 23

Type depends greatly on plate tectonic activity, type determines coastal shape and properties.

Question 24

Continental Margins: Active Margin

Answer 24

occur along subduction zones or transform faults. Volcanically and tectonically active regions. Sediments of variable thickness. (terrigeneous, carbonates, volcanics)

Question 25

Continental Margins: Passive Margin

Answer 25

Occur far from plate boundaries, flat lying, gentler gradients. Abundant shallow water sediments. (terrigeneous, carbonates)

Question 26

Coastlines Modified by:

Answer 26

waves, tides, mass wasting events, uplift.

Question 27

Coastlines are regions of

Answer 27

erosion and deposition

Question 28

Waves created ...

Answer 28

primarily by the friction between water and wind.

Question 29

Larger waves are created by:

Answer 29

earthquakes, landslides, volcanic eruptions, extraterrestrial impacts

Question 30

Wave depth is about

Answer 30

1.2 the wavelength

Question 31

In deep water, the wave speed is

Answer 31

V = L/T

Question 32

Wave strikes the beach at an angle, explain

Answer 32

Part of the wave nearest the shore hits the shallow water first and slows down, creates a bend in the wave and rest of the wave follows the bend

Question 33

Longshore Transport is

Answer 33

a shallow water current, moves parallel to the shoreline. Caused by wave refraction. Controls depositional shoreline features and erosion and transport of sediment.

Question 34

Tides are due to

Answer 34

gravitational pull of the sun and the moon.

Question 35

Types of Tides:

Answer 35

Spring and Neap

Question 36

Tides: Neap

Answer 36

low difference between low and high tides

Question 37

Tides: Spring

Answer 37

big difference between low and high tides

Question 38

Beaches are

Answer 38

gently sloping surfaces, washed over by waves, covered with sediment, deposition or erosion dominated, short-term and unstable features

Question 39

Sea Level Changes are usually

Answer 39

local to regional in effect: tectonic uplife or subsidence, isostatic rebound, global warming, human causes

Question 40

Sea Level ups and downs

Answer 40

Glaciation promotes drops and global warming promotes rises.