Oceanography Chapter 1

2. What is the Calcite Compensation Depth (CCD)?

• The Calcite Compensation Depth (CCD) is the depth in the ocean where carbonate dissolution equals carbonate supply. • The CCD, on average, is 4500 meters below sea level. Below this level, sediment does not usually contain much calcite because it readily dissolves. • CCD= the level at which calcium carbonate dissolves at an increasing rate due to increasing depth.

1. Suppose we could take the Atlantic Ocean north of the equator and divide it into two compartments along a north-south line (for example, if sea level were much lower and the Mid-Atlantic Ridge was emergent along its length). What would happen to the North Atlantic Gyre?

• The Mid-Atlantic Ridge barrier would turn equatorial currents north and northern boundary currents south, resulting in two gyres, one on each side

7. Explain the conditions that cause ENSO warm phase (El Niño)?

• The high pressure along the coast of south America weakens, reducing the difference between the high and low pressure regions of the walker circulation cell.

1. What causes most places on Earth to have seasons?

• The spin axis is tilted 23.5 degrees to the plane of Earth's orbit, causing solar radiation to vary in angle as Earth revolves around the Sun

5. Why does the sun heat up the Earth unvevenly?

• The tilt of Earths Rotational axis

5. What conditions lead to the formation of tropical cyclones?

1. Ocean water with a temperature greater then 25 degrees Celsius (77 degrees Fahrenheit) 2. Warm, moist air, which supplies vast amounts of latent heat as the water vapor in the air condenses and fuels the storm.

3. Why does ocean temperature change little from day to night?

Water is capable of storing a tremendous amount of heat and is a conductor of energy. Air is an insulator and does not make for the effective transfer of energy

3. In the Atlantic, North Atlantic Deep Water (NADW) sinks near Greenland and heads south along the ocean bottom. Antarctic Bottom Water (ABW) sinks off Antarctica and moves north along the ocean bottom. What happens when they meet?

• ABW stays on the bottom and NADW overrides it

9. What is thermohaline circulation?

• Because the density variations that cause deep ocean circulation are caused by differences in temperature and salinity, deep-ocean circulation is also referred to as Thermohaline circulation.

9. What is thermohaline circulation? (Ch. 7, Section "What Deep-Ocean Currents exist?")

• Because the density variations that cause deep ocean circulation are caused by differences in temperature and salinity, deep-ocean circulation is also referred to as Thermohaline circulation.

10. Describe the conveyer-belt circulation and how it forms. (Ch.7, Section "Worldwide Deep-Water Circulation

• Because the overall circulation pattern resembles a large conveyer belt, the model is called conveyer-belt circulation • Beginning in the north atlantic, surface water carries heat to high latitudes via the gulf stream. During the cold winter months, this heat is transferred to the overlying atmosphere warming northern Europe.

6. You are on a research cruise and you leave Japan, heading east. At about 1500 kilometers east of Japan you encounter a large volcanic plateau (Shatsky Rise) that is covered with sediments. You lower a piston core to sample the sediments and the wire indicator says 2500 meters of water depth. What kind of sediment will the core likely contain?

• Carbonate ooze

4. Which deep waters have been isolated from the surface the longest?

• Circum Antarctic Region

4. Why are the deep ocean basins covered with red clay deposits?

• Clay dominates because of the near absence of lithogeneous and biogenic particles • Their predominance is due to the absence of other materials that would dilute it.

2. What is the main cause of surface water sinking to cause the deep, thermohaline ocean currents?

• Density increase caused by cold in polar regions

5. On the whole, what is the most important mechanism of transporting continental-margin lithogenous sediments?

• Flowing water

8. ExplaiCn the conditions that cause ENSO cool phase (La Niña)?

• Larger pressure than normal conditions across the Pacific Ocean. This larger pressure difference creates stronger walker circulation and stronger trade winds, which in turn cause more upwelling, a shallower thermocline in the eastern pacific, and a and across the equatorial south pacific.

4. A non-rotating Earth would have hemispheric air circulation cells (Figure 6.7) but because of the Coriolis effect, there are three cells in each hemisphere (Figure 6.10). Suppose Earth rotated faster; what would happen to the three wind belts?

• More wind belts

8. How are oozes different from abyssal clays?

• Oozes are atleast 30% biogeneous test material while abyssal clays are at least 70% fine clay sized particles from the continent. • By volume much more ooze than abyssal clays exist on the ocean floor.

3. Why are gas hydrate deposits abundant on submarine continental margins?

• Organic marine sediments provide natural gas in which pressure is high and temperature is low

8. Why are lakes like the Dead Sea and Great Salt Lake so buoyant?

.The water is hypersaline; it has a high amount of dissolved solids, making it extremely dense and buoyant

4. The Ekman spiral affects the direction of near surface water movement. If you lowered a current measuring device over the side of a ship in the northern hemisphere, what would you observe?

As the instrument descended, the current direction would move progressively to the right of the wind until it actually was going in the opposite direction, and at greater depth it would move to the left

6. Hydrothermal vents are considered both a source and sink for ocean salts. How can one factor both add and take away salt?

As water interacts with hot rock, some materials are dissolved whereas others are deposited

5. How does the latent heat of evaporation (and its equivalent, the latent heat of condensation) moderate climate?

By absorbing energy on evaporation and releasing it on condensation, it keeps water cool when the air is hot and warm when the air is cool

5. What causes downwelling?

Convergence of surface currents

3. How can oceanographers measure surface currents from space?

Ekman transport and current motion cause the water surface to bulge and the departure from normal sea level can be measured by satellite radar

4. What does the principle of constant proportions tell us?

No matter the salinity of ocean water, the ratios of major dissolved ions remains the same

2. Why is Florida in a tropical climate while Baja California, at the same latitude, is temperate?

Ocean currents bring warm water up from the tropics to Florida but down from northern latitudes to Baja

10. What processes decrease local salinity in the ocean?

Precipitation, runoff, melting icebergs and melting sea ice decrease salinity by adding more freshwater to the ocean.

1. Why is ocean climate (and the entirety of Earth for that matter) divided into latitude parallel zones that become progressively colder from equator to pole?

The average solar radiation (sunlight) striking the surface declines from equator to poles

2. What is the unit that is equivalent to raising the temperature of 1 gram of water by 1 degree centigrade?

The definition of a calorie is "the amount Of energy required to raise the temperature of 1 gram of water by 1 degree centigrade, the other answers are not correct.

1. Many of the unique properties of water, such as cohesion and its reputation as a universal solvent, come from its atomic structure. What causes these properties?

The electrical polarization causes water molecules to stick together with hydrogen bonds. This gives them cohesion. The polarization also allows water to break down substances whose molecules are glued by ionic bonds by attracting the constituent ions.

9. Water in the ocean combines with carbon dioxide to form a weak acid called carbonic acid. But the ocean's pH is 8.1 on average, which is slightly basic. How is this so?

There is a natural buffer system

7. What is a western boundary current and how does it form?

When equatorial currents reach the western portion of an ocean basin, they must turn because they cannot cross land. The coriolis effect deflects these currents away from the equator as western boundary currents They travel along the western boundary of their respective ocean basins.

9. What is a geostrophic current?

When surface water in a subtropical convergence and the Coriolis effect are balanced

10. What is western intensification?

When the western part of the hill formed within a rotating gyre is closer to the western boundary than the center of the gyre As a result, the western boundary currents of the subtropical gyre are faster, narrower, and deeper than their eastern boundary current counterparts.

7. How does water have such strong surface tension?

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3. Describe the difference between sea ice and icebergs, including how they both are formed?

ice breaks off from coastal glaciers that reach the sea

4. Tropical storms are categorized based on what criteria?

sustained wind speed

5. What is the seasonal pattern of India's monsoon?

• During Winter, air over the Asian Mainland rapidly cools, creating high atmospheric pressure, which causes the wind to blow from southwest Asia off the continent. (northeast Monsoon) • During summer, the winds reverse.

9. Why are gas hydrates important?

• Energy resource and factoring global warming

1. Why is quartz one of the most abundant constituents of lithogenous sediments?

• Quartz is a main component of most rocks. It is resistant to abrasion and can be transported long distances and deposited far from its source area. • Its resistant to weathering.

7. Most biogenic sediments consist of tiny shells called microfossils that are made of what two substances?

• Silicon and oxygen SiO2 and calcium carbonate CaC03

6. What is the Walker Circulation Cell

• Sinking cool air dominates the coastal region of South America. On the western boundary, it is the opposite. Low pressure, rising warm air produces cloudy, rainy conditions. This causes the strong southeast trade winds to blow across the equatorial south Pacific.

2. If you travel by airplane from New York to Paris (approximately east to west across the Atlantic Ocean), which way do you have to steer the airplane to arrive in at the Paris airport?

• Slightly north of a direct line between airports

3. What causes the greenhouse effect?

• Sunlight is absorbed by the Earth's surface, reradiated as infrared energy, and absorbed by atmospheric gases