Deck 15: Restless Realm: Oceans and Coasts

Question 1

You are running a sonar survey to map the bathymetry of an ocean basin.Using the following continuous sonar data giving the depth of the seafloor,what feature have you just discovered?
$\begin{array}{c}\begin{array}{|c|} \hline \text {Depth}\\ \text {Reading}\\ \text {Number}\\\hline 1 \\\hline 2 \\\hline 3 \\\hline 4 \\\hline 5 \\\hline 6 \\\hline 7 \\\hline 8 \\\hline 9 \\\hline 10 \\\hline 11 \\\hline 12 \\\hline 13 \\\hline 14 \\\hline 15 \\\hline 16 \\\hline 17 \\\hline 18 \\\hline 19 \\\hline 20 \\\hline\end{array}\begin{array}{c|}\hline\\\text { Depth (m) }\\\\\hline 3131 \\\hline 3101 \\\hline 3071 \\\hline 3011 \\\hline 2891 \\\hline 2846 \\\hline 2756 \\\hline 2577 \\\hline 2532 \\\hline 2487 \\\hline 2502 \\\hline 2577 \\\hline 2756 \\\hline 2921 \\\hline 3041 \\\hline 3026 \\\hline 2936 \\\hline 2756 \\\hline 2577 \\\hline 2487 \\\hline \end{array}\end{array}$

A)an abyssal plain
B)a deep trench
C)a mid-ocean ridge
D)a continental shelf

Answer 1

a mid-ocean ridge

Question 2

Compared with the continental crust,the oceanic crust is ________.

A)denser
B)less dense
C)about the same density
D)about half as dense

Answer 2

A

Question 3

Compared with the continental lithosphere,the oceanic lithosphere is ________.

A)thicker
B)thinner
C)approximately the same thickness
D)exactly five times thinner

Answer 3

B

Question 4

Where do the deep ocean currents rise to the surface?

A)the equator
B)the North Pole
C)the tropics
D)the South Pole

Question 5

________ provides the largest tide-generating force.

A)The Sun
B)The Moon
C)Earth
D)The ocean

Question 6

Mid-ocean ridges (MORs),which are the sites of new oceanic crust formation,are linear mountain chains that run along divergent plate boundaries.Why does a MOR sit up higher than the surrounding oceanic crust?

A)Hot materials are less dense and shrink;thus,the new crust will sit higher than the surrounding crust.
B)As the hot magma exits the MOR,it shoots up higher than the surrounding crust.
C)Hot materials are less dense and expand;thus,the new crust will sit higher than the surrounding crust.
D)Hot,geothermal waters cause the new crust to expand and sit higher than the surrounding crust.

Question 7

According to this map,where are you most likely to find upwelling currents?

A)the North Pole
B)the equator
C)the tropics
D)the South Pole

Question 8

The density of seawater increases with ________ temperature and ________ salinity.

A)increasing;increasing
B)decreasing;increasing
C)increasing;decreasing
D)decreasing;decreasing

Question 9

Which of the following would be an area of the ocean with the LEAST dense water?

A)the mouth of the Amazon River
B)off the coast of Africa
C)the middle of the Pacific Ocean
D)off the coast of Madagascar

Question 10

The sea surface salinity is ________ at the mouth of the Amazon River and ________ in the Great Salt Lake,Utah.

A)low;low
B)high;low
C)low;high
D)high;high

Question 11

Using the figure below,which of the following lists correctly identifies the various seafloor landforms?

A)A = continental shelf,B = abyssal plain,C = mid-ocean ridge,D = trench
B)A = abyssal plain,B = continental shelf,C = mid-ocean ridge,D = trench
C)A = continental slope,B = mid-ocean ridge,C = trench,D = volcanic arc
D)A = continental shelf,B = abyssal plain,C = trench,D = mid-ocean ridge

Question 12

The shallowest portions of an ocean found along the margins of continents are the ________.

A)abyssal plains
B)continental rises
C)continental shelves
D)continental slopes

Question 13

The deepest segments of the ocean floor are found ________.

A)along mid-ocean ridges
B)in the geographic centers of abyssal plains
C)in trenches associated with passive margins
D)in trenches associated with subduction zones

Question 14

What type of material would you expect to find on the continental slope?

A)basalt and plankton shells
B)carbonate-rich sediments and shells
C)silicic-rich gravels and plant remains
D)metamorphosed oceanic crust

Question 15

Thermohaline circulation carries ________ water from the poles to the equator,where the water becomes ________.

A)warm;cold
B)cold;warm
C)low density;more dense
D)low density;more salty

Question 16

Which is the larger of the two tidal bulges?

A)the one farthest from the Sun
B)the one farthest from the Moon
C)the one closest to the Sun
D)the one closest to the Moon

Question 17

The Coriolis effect causes the apparent deflection of currents due to ________.

A)changes in wind speed
B)the rotation of Earth
C)changes in ocean currents
D)the location of the Moon

Question 18

How would the Coriolis effect affect the space station?

A)The space station would curve to the right because it is above the Northern Hemisphere.
B)The space station would curve to the left because it is above the Southern Hemisphere.
C)The space station would not curve because it is above the equator and not affected.
D)The space station would not be affected because it is not in Earth's atmosphere.

Question 19

The form and topography (depth profile)of the ocean floor is termed ________.

A)orogeny
B)bathymetry
C)allocthony
D)aquitopography

Question 20

Major oceanic surface currents travel ________.

A)parallel to the prevailing wind direction in a region
B)in direct opposition to prevailing winds as a result of the Coriolis effect
C)at an angle to prevailing winds as a result of the Coriolis effect
D)at an angle to prevailing winds as a result of the Doppler effect

Question 21

________ are gently sloping areas on coastlines that consist mostly of sand.

A)Tidal flats
B)Beaches
C)Lagoons
D)Inlets

Question 22

Longshore current is the result of waves ________.

A)coming in perpendicular to the shore
B)coming into shore at an angle
C)created during large storms
D)retreating back to the ocean

Question 23

Barrier islands are constantly moving in the direction of ________.

A)the longshore drift
B)the high tide
C)down welling
D)the Coriolis effect

Question 24

A wave will disturb the water to a depth equal to ________.

A)its wavelength
B)its surface amplitude
C)the bottom of the seafloor
D)one-half of its wavelength

Question 25

In the figure below,which direction is the longshore drift?

A)south
B)east
C)west
D)It is not possible to tell.

Question 26

What prevents each spot on Earth from experiencing two high tides and two low tides a day?

A)the shape of the seafloor and coastline
B)the shape of the tidal bulges
C)the position of the Moon relative to Earth
D)the position of the Sun relative to the Moon

Question 27

High tide will be ________ when the Sun and Moon are aligned parallel to each other as opposed to normally (when they are not aligned parallel to each other).

A)the same
B)lower
C)higher
D)reversed

Question 28

Why are waves larger during storms?

A)The larger wind speeds create more shear.
B)The storm increases the amount of upwelling.
C)There is more water pulled in by the storm.
D)The motion of the water becomes more elliptical.

Question 29

In the figure below,which letters represent the crest and trough?

A)A and B
B)E and D
C)C and D
D)C and B

Question 30

Which of the following figures shows a coast experiencing high tide?

A)A
B)B
C)C
D)D

Question 31

Longshore currents ________ the shoreline.

A)flow directly toward
B)flow directly away from
C)flow parallel to
D)are not affected by

Question 32

When sea level rises and floods a glacially carved valley,the area is called a(n)________.

A)fjord
B)wetland
C)estuary
D)reef

Question 33

As a wave passes through the open ocean,the water molecules move ________.

A)horizontally
B)diagonally
C)in a circular path
D)straight up and down

Question 34

What would happen to the tides if the Sun and Moon are aligned?

A)There would be no tides at all.
B)There would be no low tides on Earth.
C)High tide would be much larger.
D)There would be only low tides on Earth.

Question 35

What will eventually happen to the headlands in the figure below?

A)They will join as the bays in between fill with sediment.
B)They will become a straight line of cliffs as rock is eroded away.
C)They will remain as they are for millions of years.
D)The sea will submerge them as the terrace is uplifted.

Question 36

If a beach is in an east-west orientation and the waves are approaching the shore from a southeasterly direction,in which direction will the longshore drift be?

A)northern
B)western
C)southern
D)eastern

Question 37

Coastal landforms are constantly changing because the ________.

A)sand is constantly moving
B)tides are getting stronger
C)sand is moved by developers
D)storms are getting stronger

Question 38

Waves are created by ________.

A)tides
B)the Moon
C)the crust
D)wind

Question 39

Because of wave refraction,erosion along an irregular coastline is ________.

A)even along the length of the coast
B)greatest along headlands
C)greatest in bays
D)the same as it would be along a regular coastline

Question 40

The castle on the island of Mont Saint-Michel,France,can be accessed ________ a day during ________ tide.

A)twice;high
B)once;low
C)twice;low
D)once;high

Question 41

If sea level continues to rise and covers the city of Miami,the Florida coast will become a(n) ________.

A)emergent coast
B)submergent coast
C)continental slope
D)abyssal plain

Question 42

Explain why it is not a good idea to build on barrier islands.

Question 43

Building a dam across a river can lead to ________ because sediment becomes trapped behind the dam.

A)pollution
B)beach nourishment
C)reef bleaching
D)beach erosion

Question 44

Why do beaches become sediment-starved after dams are installed on rivers?

A)Dams trap water,thus reducing the volume of water that enters the ocean and erodes away the coast to produce sediment.
B)Rivers supply sediment to beaches;dams trap river sediment,and thus that sediment cannot make it to the beaches.
C)The chemical composition of river water is changed when it flows through a dam;this alters the amount of chemical weathering that occurs along the coast.
D)Dams are built using sediment covered in concrete;the sediment most often comes from nearby beaches.

Question 45

Sea level is currently rising at 3.3 mm/yr,and scientists predict that global warming could cause a rise in sea level of 7 if left unabated.How long will it take the sea to rise 7 m at the current rate?

A)2,121 years
B)0.0004 year
C)2.121 years
D)0.47 year

Question 46

Many rocky coasts occur along active margins;why is this?

A)Active margins are associated with larger storms,which causes more erosion of sediment,leading to fewer beaches.
B)Active margins are associated with volcanic activity,and volcanic rocks are very hard to erode;thus,there is not enough sediment produced.
C)Active margins often experience repeated uplift,and thus the waves have not had sufficient time to erode the land surface down to sea level.
D)Active margins tend to have far fewer streams that feed sediment to the oceans;thus,there is not enough sand to create beaches.

Question 47

When the sea level rises,an ocean may invade a river valley,producing a nearshore body of water of mixed and variable salinity termed a(n)________.

A)atoll
B)lagoon
C)estuary
D)jetty

Question 48

The entire state of Florida is composed of fossiliferous limestone.What does this imply about Florida during the recent past?

A)It was covered with caves.
B)It was a submergent coast.
C)It was an emergent coast.
D)It was in the mountains.

Question 49

Describe what thermohaline circulation is and how it works.

Question 50

Along beaches,groins have ________.

A)solved the problem of beach drift
B)increased erosion rates immediately up current from the groin
C)increased erosion rates immediately down current from the groin
D)increased depositional rates immediately down current from the groin

Question 51

Describe what longshore drift is and how it works.

Question 52

You have just bought your dream home along a coastline,but you notice that the beach in front of your new house is slowly disappearing.You decide to solve this by building a groin.Winds blow predominantly from east to west.Where do you place your groin?

A)parallel to the shoreline several meters offshore
B)perpendicular to the shore to the east of your house
C)perpendicular to the shore to the west of your house
D)perpendicular to the shore directly in front of your house

Question 53

Describe one way humans have tried to mitigate beach erosion.Was it ultimately successful in both the short term and long term?

Question 54

Which type of coastline would most likely contain estuaries or fjords?

A)subductive
B)emergent
C)submergent
D)divergent

Question 55

Label the landforms of ocean basins shown in the image below using the following word bank (note: not all of the words will be used):