Deck 10: The World Ocean

Question 1

How would this planet differ if there was one giant ocean basin and one giant continent only? In your analysis discuss how oceanic circulation would differ. How would this affect climate on the planet and the distribution of ecosystems?

Answer 1

If this planet had one giant ocean basin and one giant continent only, there would be significant differences in oceanic circulation, climate, and the distribution of ecosystems compared to the current Earth.

Oceanic circulation would be greatly affected by the presence of only one giant ocean basin. The circulation patterns, such as the Gulf Stream and the Antarctic Circumpolar Current, which are driven by the interaction of different ocean basins and continents, would not exist in the same way. This would lead to a more uniform distribution of ocean temperatures and currents, potentially impacting global climate patterns.

The presence of one giant continent would also greatly impact climate on the planet. Landmasses play a significant role in shaping climate through processes such as evaporation, precipitation, and the reflection of sunlight. With only one giant continent, there would be a more uniform distribution of these processes, resulting in a more consistent and potentially less varied climate across the planet.

In terms of the distribution of ecosystems, the presence of one giant continent and one giant ocean basin would likely lead to a more homogenous distribution of ecosystems. The current Earth's diverse range of ecosystems is largely shaped by the presence of different landmasses and ocean basins, which create varied habitats for different species. With only one of each, the range of habitats and ecosystems would likely be more limited, potentially leading to a less diverse planet in terms of biodiversity.

Overall, the presence of one giant ocean basin and one giant continent would have significant impacts on oceanic circulation, climate, and the distribution of ecosystems on the planet. It would likely lead to a more uniform and less diverse planet compared to the current Earth.

Question 2

If outgassing of volcanoes continues today, why aren't the ocean basins accumulating more and more water? By now, after 4 billion years since the origin of the oceans, shouldn't the oceans have completely covered the continents?

Answer 2

The outgassing of volcanoes does contribute to the water content of the Earth's oceans, but it is not the only factor at play. The water cycle, which includes processes such as evaporation, precipitation, and runoff, helps to regulate the amount of water in the ocean basins. Additionally, the movement of tectonic plates and the formation of new land through processes such as erosion and sedimentation also play a role in maintaining the balance of water on Earth.

Furthermore, the Earth's climate and temperature have fluctuated over the past 4 billion years, leading to periods of glaciation and ice ages that have influenced the distribution of water on the planet. These natural processes have prevented the oceans from completely covering the continents, despite the ongoing outgassing of volcanoes.

In summary, while the outgassing of volcanoes does contribute to the water content of the oceans, there are a variety of geological and climatic factors that work together to regulate the distribution of water on Earth. As a result, the oceans have not completely covered the continents, even after 4 billion years since their origin.

Question 3

__________ covers 70.8 percent of Earth's surface.

Answer 3

Seawater

Question 4

Primitive meteorites called __________ are considered to be samples of the same material that accreted to form Earth.

Question 5

__________ is the measure of the sea's saltiness.

Question 6

One of the most important factors affecting salinity is __________ , which removes fresh water and leaves the remaining water saltier.

Question 7

The __________ zone typically extends to a depth of 100 to 500 meters.

Question 8

The rapid increase in water density with depth defines the __________ .

Question 9

The direction taken by ocean currents is influenced by wind and the __________ force.

Question 10

If the net Ekman transport is toward the coast, the surface water thickens and sinks in a process known as __________ .

Question 11

Surface ocean waves receive their energy from __________ that blow across the water surface.

Question 12

The distance between two equivalent points on a wave is called the __________ .

Question 13

Turbulent __________ is defined as wave activity between the line of breaking waves and the shore.

Question 14

__________ are often erroneously called "tidal"
waves.

Question 15

__________ are caused by the gravitational attraction between the Moon, Sun, and Earth.

Question 16

A __________ consists of wave-washed sediment along a coast, including sediment in the surf zone.

Question 17

Many of the world's warm-water coastlines are characterized by limestone __________ , vast colonies built by corals and other carbonate-secreting organisms.

Question 18

Nearly all coasts have experienced __________ , a rise of water level relative to the land over the past 10,000 years.

Question 19

The melting of __________ ice does not have a dramatic impact on sea level.

Question 20

The abundant yield of __________ , currently more than 80 million tons per year, is just one of the many services proved to humankind by the world ocean.

Question 21

Seawater covers nearly 71% of Earth's surface.

Question 22

Earth has had liquid water on its surface for at least 4 billion years.

Question 23

The salinity of seawater is about 5.0 percent by weight.

Question 24

Sea-surface temperatures a strongly related to latitude.

Question 25

The thermocline does not coincide with the pycnocline or the halocline.

Question 26

The lowermost water of the ocean constitutes the pelagic zone.

Question 27

Calcareous ooze is oceanic sediment that consists of the skeletal remains of sea organisms.

Question 28

The Coriolis Effect causes all moving bodies to be deflected to the right in the southern hemisphere and to the left in the northern hemisphere.

Question 29

Currents in northern hemisphere gyres circulate in a clockwise direction, whereas those in the southern hemisphere circulate counterclockwise.

Question 30

El Nino occurs every few years when the trade winds and their associated currents weaken or even reverse.

Question 31

Dense, cold, saline North Atlantic Deep Water (NADW) originates at several sites near the surface of the South Atlantic.

Question 32

Surface ocean waves receive their energy from winds that blow across the water surface.

Question 33

Wave reflection occurs when the direction of an incoming wave realigns as it enters shallow water near a coastline.

Question 34

A tsunami is a water wave that is generated by strong winds.

Question 35

Tides are caused by the gravitational attraction between Earth, Moon, and the Sun.

Question 36

Estuaries occur where fresh and saltwater mix in the coastal environment.

Question 37

Sediment inputs and outputs in shoreline systems are locally balanced.

Question 38

Very few coasts show evidence of past submergence or emergence.

Question 39

If all land ice were to melt, sea levels would likely increase by about 65 to 80 meters.

Question 40

One of the most important contributions of the ocean to the Earth system is its moderating influence on climate.

Question 41

Where did most of Earth's surface water originate?

A) From natural springs.
B) Transpiration from plants.
C) Outgassing of volcanoes.
D) From lunar fragments.

Question 42

What is the thermocline?

A) A layer of ocean water that has a major temperature shift from the layer of water above.
B) A layer of ocean water that has a major salinity shift from the layer of water above.
C) A layer of ocean water that has a major density shift from the layer of water above.
D) All of these.

Question 43

Why is calcareous ooze rare or absent on the deepest parts of the ocean floor?

A) Below a certain depth, they will be eaten by bottom feeders.
B) Below a certain depth, the deposits will dissolve in the water.
C) Below a certain depth, there is not enough light to support the existence of the deposits.
D) None of these.

Question 44

Where are the highest ocean surface salinities found?

A) In areas where evaporation is less than precipitation.
B) In areas where evaporation is greater than precipitation.
C) In areas where evaporation equals precipitation.
D) Not enough information provided.

Question 45

Where are the lowest ocean surface salinities found?

A) In areas where there is a lot of ice generation.
B) In areas where there is a lot of sea ice melt.
C) In areas where evaporation equals precipitation.
D) Not enough information provided.

Question 46

Where does most of the heat supplied to the ocean originate?

A) Large sea animals.
B) Hydrothermal vents.
C) Human activities.
D) The Sun.

Question 47

What factors affect the depth of the photic zone (the photic zone is the depth that sunlight travels down the water column)?

A) Salinity and temperature.
B) The intensity of solar radiation.
C) The amount of ocean mixing.
D) The amount of biological activity in the surface zone.
E) All of these.

Question 48

Why is the thickness of ooze along the ocean floor not always an accurate indication of the biological productivity of surface water in a given area?

A) Beyond certain depths, both calcareous and siliceous ooze will tend to dissolve in the water.
B) Animal remains tend to get eaten in the upper layers and therefore will never fall to the bottom.
C) Marine life generally migrate and don't stay in any one place that long.
D) Currents take most of the material away.

Question 49

The density of a parcel of seawater will increase when

A) The pressure decreases.
B) The temperature increases.
C) The salinity decreases.
D) The salinity increases.

Question 50

What are the three most important factors that affect wind wave development?

A) Strength of wind, fetch, seismic activity.
B) Seismic activity, volcanic activity, glacial activity.
C) Strength of wind, fetch, duration of wind.
D) Strength of wind, duration of wind, volcanic activity.

Question 51

The wavelength determines the size of the orbits of water molecules within a wave, but what determines the shape of the orbits?

A) The fetch.
B) The strength of the wind.
C) The duration of the wind.
D) The depth of the water.

Question 52

What are waves that move through water deeper than one-half their wavelength known as?

A) Shallow water waves.
B) Deep water waves.
C) Transitional waves.
D) Big waves.

Question 53

What happens to the tides if the Earth, Moon, and Sun are all in a line?

A) Lowest high tides.
B) Highest high tides.
C) Moderate high tides.
D) Moderate low tides.

Question 54

What geologic areas are most likely to experience tsunamis?

A) Areas of spreading centers.
B) Areas of transforms faults.
C) Areas of subduction zones.
D) Areas with large amounts of sea ice.

Question 55

Assume a deep water wave: Would a diver at 20 meters depth notice the passage of a wind wave that has a wavelength of 30 meters? Why?

A) No, because the diver is greater than one-half the depth of the wavelength.
B) No, because the diver is less than 1/20 the depth of the wavelength.
C) Yes, because the diver is less than one-half the depth of the wavelength.
D) Yes, because the diver is within the wave motion.

Question 56

Why does the Antarctic Ocean have the greatest chance of having very large wind waves?

A) Short fetch.
B) Long fetch.
C) Lots of glacial activity.
D) Lots of seismic activity.

Question 57

What would a ship feel if a tsunami passed beneath it in the open ocean?

A) A series of odd vibrations.
B) Severe shaking.
C) A large roll.
D) Nothing.

Question 58

Where is the Coriolis force the strongest?

A) At the Equator.
B) At the poles.
C) At the mid-latitudes.
D) In the middle of the Pacific Ocean.

Question 59

What are the forces that cause the ocean to circulate?

A) Gravity.
B) Coriolis force.
C) Wind.
D) All of these.

Question 60

What direction do gyres turn in the northern hemisphere? Why?

A) Counterclockwise due to the Coriolis.
B) Clockwise due to the Coriolis.
C) Clockwise due to land boundaries.
D) Counterclockwise due to land boundaries.

Question 61

What causes a wave approaching the beach at an angle to break parallel to the beach?

A) Reflection.
B) Refraction.
C) Diffraction.
D) Salinity.

Question 62

Explain the differences in winter temperatures at the same latitudes along the Atlantic boundaries of England and Canada.

A) England receives cold air from the north and Canada receives warm air from the south according to the North Atlantic gyre.
B) England is part of an island system and Canada is not.
C) There is no difference in winter temperatures.
D) None of these.

Question 63

A wave is composed of a crest and trough. With this said, what are high tides and what are low tides?

A) High tide = crest; low tide = crest.
B) High tide = trough; low tide = crest.
C) High tide = crest; low tide = trough.
D) High tide = trough; low tide = trough.

Question 64

What is one of the reasons why the Antarctic bottom water is so dense?

A) It is extremely warm.
B) It is extremely cold.
C) It's temperature is moderate.
D) The water is rich in oxygen.

Question 65

A drift bottle is tossed into the ocean off the coast of Peru. Three years later the bottle is recovered on a beach in northern California. Describe the most likely path of the bottle from Peru to California, assuming it to have been transported solely by ocean surface currents.

A) Peru Current; South Equatorial Current; North Equatorial Current; Kuroshio Current; North Pacific Current; California Current.
B) Peru Current; South Equatorial Current; North Equatorial Current; Gulf Stream
C) Peru Current; South Equatorial Current; Antarctic Circumpolar Current; South Equatorial Current; Gulf Stream
D) Peru Current; South Equatorial Current; Antarctic Circumpolar Current; South Equatorial Current; North Equatorial Current; California Current.

Question 66

Along what type of coastline would a large estuary be most common?

A) Emergent.
B) Submergent.
C) Subduction zone.
D) Spreading center.

Question 67

What are currents within the surf zone that follow parallel to the shore known as?

A) Gyres.
B) Shortshore currents.
C) Longshore currents.
D) Deep water currents.

Question 68

What is the rising of cold water from deeper layers (to replace warmer surface water) known as?

A) Downwelling.
B) Upwelling.
C) Emergent.
D) Submergent.

Question 69

Deep ocean circulation is driving by variations in water temperature and salinity. What is this called?

A) Thermohaline circulation.
B) Pycnocline circulation.
C) Halocline circulation.
D) Thermocline circulation.

Question 70

Can you think of a way to float low salinity saltwater over no salinity freshwater?

A) Yes. Lower the density of the saltwater by heating it.
B) Yes. Lower the density of the saltwater by cooling it.
C) No. It is impossible. Saltwater is heavier (denser) than freshwater.

Question 71

Coastal erosion can be devastating to communities and ecosystems along the coastline. There are a number of ways to prevent -- or at least slow down -- this erosion. Which of the following is not one of those ways?

A) Retreat.
B) Hard stabilization.
C) Medium stabilization.
D) Soft stabilization.

Question 72

What is the generally order of events for the evolution of an island to an atoll?

A) Subsidence and upward reef growth; rapid extrusion of lava; continued subsidence (fringing reef becomes barrier reef).
B) Subsidence (fringing reef becomes barrier reef); continued subsidence and upward reef growth; rapid extrusion of lava.
C) Subsidence and upward reef growth; continued subsidence (fringing reef becomes barrier reef); rapid extrusion of lava.
D) Rapid extrusion of lava; subsidence (fringing reef becomes barrier reef); continued subsidence and upward reef growth.

Question 73

Heating of the oceans leads to

A) Development of calcareous and siliceous ooze.
B) A variety of temperatures in different parts of the world.
C) Circulation of air and ocean.
D) All of these.

Question 74

What are the top four ions in seawater, in their order of abundance?

A) Chloride, sodium, sulfate, potassium.
B) Chloride, sodium, sulfate, magnesium.
C) Sodium, chloride, magnesium, sulfate.
D) Sulfate, calcium, chloride, sodium.

Question 75

About how long has Earth had liquid water on its surface?

A) 2 billion years.
B) 4.6 billion years.
C) 4 billion years.
D) 4 million years.