Lecture 16: Oceans 2

Question 1

Why do Waves occur?

Answer 1

Due to the effects of wind acting on the surface of the ocean

Question 2

What is the movement of waves?

Answer 2

Looping orbitals in which motion decreases downward to the wave base

Question 3

How does Shallow water effect waves?

Answer 3

Wave orbitals flatten in shallow water because of drag

Question 4

What is Wave Refraction?

Answer 4

When waves become more parallel to seafloor contours (and the shore) as the wave encountours the sea floor

Question 5

What is Longshore drift?

Answer 5

When waves approach the shore obliquely and undergo refraction and the oscillating motion of water is converted to a longshore current

Question 6

What is Longshore Drift?

Answer 6

When sediments are carried along the shore during longshore drift? lol

Question 7

What are Tides?

Answer 7

Rise and fall of the level of the ocean at coastlines twice per day due to gravitation interactions between the earth with the moon and sun

Question 8

Which body is more important to do with tides?

Answer 8

The moon

Question 9

Which two bodies have a common center of gravity and where is it located?

Answer 9

The earth and the moon and it is in the earth because the earth has more mass

Question 10

Why is water pulled toward the moon?

Answer 10

Because the moon’s gravity on the earth’s side is stronger than necessary to maintain orbit. This is why water on the far side pulls away from the moon

Question 11

What shape is the Hydrosphere pulled into?

Answer 11

An ellipsoid shape

Question 12

How often do High tides occur?

Answer 12

Twice every 24 hours and 50 minutes

Question 13

How is tide perceived in shallow water?

Answer 13

Tide is amplified so it is more dramatic than in the ocean

Question 14

What are Spring tides?

Answer 14

When the sun and moon are in line with the earth and create the seasonally extreme tides: The highest high tides and the lowest low tides

Question 15

What are Neap Tides?

Answer 15

When the sun and moon are at 90º to each other with respect to the earth and the gravitational effects of the sun and the moon partially cancel out and the tides that occur are the mildest of the year

Question 16

What are Eustatic changes?

Answer 16

Changes that result from a combination of worldwide sea-level change

Question 17

What do Eustatic changes result from?

Answer 17

Changes in climate

Question 18

How is Ice related to Eustatic sea changes?

Answer 18

During climate change ice forms and reduces the level of water reducing global sea levels

Question 19

How do Tectonic plates affect Eustatic change?

Answer 19

They change the ocean basins which directly impact sea level

Question 20

What can cause local changes to sea level?

Answer 20

• Tectonic plate movements
• Isostatic responses to ice sheets and ice caps
• Compaction of sediments

Question 21

What is Isostatic depression and post-glacial rebound?

Answer 21

When ice melts or glaciers move causing regional differences in tide due to the rebounding of the mantle

Question 22

Where can Ocean sediments be deposited?

Answer 22

In oceans near to the coast, on the continental shelf, or in the deep ocean

Question 23

In what way can ocean sediments be deposited on the coast?

Answer 23

Via deltas, estuaries and beaches

Question 24

What are deep ocean sediments known as?

Answer 24

Pelagic sediments

Question 25

What does the Benthic Zone refer to?

Answer 25

The bottom of the ocean and the organisms that live there

Question 26

What is the Pelagic zone?

Answer 26

The water column

Question 27

What can the Pelagic zone be divided by?

Answer 27

Depth

Question 28

What is the Photic zone?

Answer 28

The top 200 meters where sunlight reaches

Question 29

What is the Aphotic zone?

Answer 29

The area below the Photic zone

Question 30

What is the Littoral Zone?

Answer 30

The thin region near to the shore that experiences tides

Question 31

Where does the Neritic zone span?

Answer 31

The position of low tide to the continental shelf slope

Question 32

What is the Oceanic zone?

Answer 32

The zone beyond the shelf

Question 33

Where do Deltas form and what are they?

Answer 33

In areas where a river enters into the sea and the erosional action of waves and currents in not great enough to remove all of the sediment being transported by a river causing sediment to pile and build up

Question 34

What are Estuaries?

Answer 34

Semi-enclosed embayments that are fed by freshwater from one or more rivers

Question 35

What are the characteristics of Estuaries?

Answer 35

Rapid change in water salinity
Significant sediment deposition may occur
Hosts a great variety of plant and animal life

Question 36

What are Beaches?

Answer 36

Accumulations of well sorted sediment that lie at the edge of water bodies such as oceans

Question 37

Where may sediment from beaches arise?

Answer 37

Weathering and erosion of adjacent rock or from sediment transported to the oceans from river

Question 38

What causes more sediment on beaches?

Answer 38

Weaker wave like action

Question 39

What are Continental shelves?

Answer 39

Large areas that are part of the continent where depth below sea level is greater than 200m and are covered with clastic sediment (sand and mud) or carbonate sediment

Question 40

What are Carbonate Shorlines?

Answer 40

When organisms build reefs, structures of calcium carbonate and build them up from the sea floor producing atolls around former volcanic islands

Question 41

What are Pelagic sediments?

Answer 41

Sediments that cover the deep ocean and are primarily composed of pelagic clay and pelagic ooze

Question 42

What is Pelagic ooze?

Answer 42

The shells of microscopic organisms

Question 43

How do Turbidites form?

Answer 43

Avalanches underwater of pelagic sediment that falls at the continental slope

Question 44

What are Carbonate shells more susceptible to?

Answer 44

Dissolution before deposition but carbonate oozes are more common