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45 Cards in this Set

  • Front
  • Back
Know the origin of Earth’s oceans.
In many of the dayglow images of earth obtained by the satellite, there are distinct dark spots. These spots are created when small icy comments vaporize in the outer atmosphere, creating clouds of water vapor that absorbs the ultraviolet radiation of earth’s dayglow over a small area. The water in the comets condense to form a layer of water on earth’s surface.
Know the origin of free oxygen in Earth’s atmosphere.
What is the mean temperature of Earth?
The mean surface temperature is 16°C (61°F)
What is the average depth of the oceans?
Mean dept of the oceans is about 3.8 km
What percentage of Earth’s surface is covered by water?
71% of the earth is covered by water
List the four world oceans. Arrange them in order off depth, area and volume.
Area - Pacific, Atlantic, Indian , Arctic Volume - Pacific, Atlantic, Indian , Arctic
Depth - Pacific ,Indian , Atlantic, Arctic
Know the difference between P-waves and S-waves.
P-waves oscillate in the direction of motion; They can penetrate liquids and solids.

S-waves oscillate perpendicular to the direction of propagation; they can penetrate solids.
What is a “subduction zone”? Where are they typically found? What feature (trench or ridge/rise) is found near them and what kind of earthquakes (deep or shallow) are found near them?
When a higher density ocean plate collides with a lower density continental plate, it is subducted into the mantle.
Subduction process depresses sea floor, forming a trench.
Areas of descending older oceanic lithosphere are subduction zones.
What is the primary mechanism to explain seafloor spreading?
Convection cells- formed by flow of magma in the asthenosphere in circular-like patterns; this motion is generated by the heat of the earth’s interior.
How they lead to sea floor spreading:
-Some of the rising magma breaks through the lithosphere of the sea floor to produce underwater volcanoes and to form the mid-ocean ridges/rises
-most of the rising magma is turned literally under the lithosphere, cooling and dragging pieces of the lithosphere with it effectively generating sea floor spreading.
-As magma begins to sink, it “drags” the lithosphere down, fracturing the sea floor and generating deep-sea trenches.
What is a “ridge” or “rise?” What is the difference between them and where are they typically found? Know the differences between the ridge/rise system and the subduction zones.
There is a series of mountain ranges through the ocean basins. If these mountain ranges are steep and the width of the ranges is narrow, they are referred to as ridges. If the slopes are gentler and their width is broad, they are called rises.
What kind of earthquakes (deep or shallow) are found near ridges and rises?
What is the difference between a seamount, guyot, platform and island arc system.
Seamount- Isolated volcanic peak that rises 1000m from the sea floor.
Guyots- old, flat topped, underwater seamounts
Platform- a continental area covered by relatively flat or gently tilted, mainly sedimentary strata, which overlie a basement of consolidated igneous or metamorphic rocks of an earlier deformation.
Island arc system – chain of volcanic islands formed above the sinking plate at a subduction zone
What are “hot spots?” What do they tend to produce on a moving tectonic plate? (Hint: the Hawaiian Island chain.)
Hot spots are surface expressions of persistent rising plume of hot mantle material. They are found in the center of plates and at mid-ocean ridges/rises.
Seamounts result from hot pot activity in warm waters.
Know the difference between passive and active continental margins.
Active margin- the edge of the overriding plate at the trench or subduction zone
Passive Margin- the continental margin closest to the mid-ocean ridge
Where do coral reefs form? How do coral reefs become atolls?
Islands are often surrounded by fringing coral reefs.
As seamounts slowly subside, the coral reefs that remain at the surface are called atolls
Be familiar with the heat (amount of calories) necessary to move water back and forth through its various phase changes. What is meant by “latent heat?”
Water to Ice: 80 Calories
Water to Water Vapor: 540 Calories
Warming Water from 0 degrees Celcius to 100 degrees Celcius: 100 Calories

Heat lost/gained in changing 2 gram of water from one state to another of constant temperature is called latent heat; it varies with temperature.
At what temperature … does fresh water freeze? … reach its maximum density?
Highest H bonding of pure water molecule is at 4°C. Density of a maximum at this temperature.
At what temperature … does seawater freeze? … reach its maximum density?
Seawater 4°C reached max density at 1.0278g/cm3. Seawater of low salt concentration will reach max. density before freezing at temperature less then 0°C. If the salt content is greater then 24.7 g/kg, freezing occurs before a maximum density is reached.
How do the speeds of light and sound in water compare to that in air?
Speed of sound in water averages 4.5 times greater than in air.
The speed of light is faster in air than in water.
How does the speed of sound in water vary with temperature, pressure and salinity?
Speed of sound Increases with temperature, pressure and salinity.
What is the process (the steps) in which sea ice forms?
1. Thin “pancake” ice formed by freezing
2. Floes formed by joining of ice
3. Ridges and hummocks formed by collision of floes
4. Large build-ups of (2) and (3) to form ice masses
At what latitudes does one find the lowest and highest salinities on Earth?
25 degrees North and 25 Degrees South Latitude
What is the primary difference between icebergs and other forms of sea ice?
When pieces of land ice break off and fall into the sea, these pieces of freshwater ice are called icebergs.
What is the average salinity value (‰) of seawater?
Average value of salinity is 3.5% or 35 grams of salt per 1 kg of sea water
Where on Earth are the areas (i.e., latitude belts) of lowest and highest salinity?
Lowest Salinities: 40-50 degrees North and South

Highest Salinities: 25 degrees North and South. 5 degrees North.
Know the percentage of the primary gases (N2, O2, CO2) in the atmosphere as compared to that in surface seawater, and to that in the total oceans.
Nitrogen: 78% in Atmosphere, 48% in Surface Seawater, 11% in total oceans

Oxygen: 21% in Atmosphere, 36% in Surface Seawater, 6% in total oceans

Carbon Dioxide: .03% in atmosphere, 15% in surface seawater, 83% in total oceans
Know how the buffering effect of CO2 in seawater can neutralize acid rain falling over the oceans. Is seawater generally acidic or alkaline (what is its pH)?
This continual ability of carbon dioxide to produce/remove hydrogen icons (H+) in the ocean, acts as a buffer which keeps hydrogen concentrations in seawater “in check”.
Since hydrogen concentrations in any substance is measure of its acidity/ alkalinity or its pH of seawater between 7.5 and 8.5. Seawater is slightly Alkaline or basic.
Qualitatively describe “Stefan-Boltzmann’s Law” and “Wien’s Displacement Law.”
Stefan-Boltzmann’s Law (energy of radiation): the energy emitted by an object is directly proportional to the 4th power of its temperature
Wien’s Displacement Law (max wavelength of radiation): the maximum wavelength of radiation emitted by an object is inversely proportional to its temperature
What is the most destructive aspect of a hurricane?
The most destructive aspect of a hurricane is the storm surge or storm tide
Know the circulation changes that occur over the South Pacific to create “El Nino.”
Over South Pacific, trade winds relax allowing warm water to “slosh” black towards the east, towards South American. This can bring showers to Western South American and drought to Indonesia and Tropical Australia.
Is humid air heavier or lighter than dry air? Explain.
Moist air is lighter than dry air. When water vapor is added to the atmosphere, the relatively low molecular-weight water molecules replace higher molecular-weight permanent gases.
How does the density of seawater change with increases and decreases in temperature, salinity and pressure?
Density of seawater:
a) decrease with increasing temperature
b) increases with increasing salinity
c) increases with increasing pressure
What is “sigma-t?” Be able to convert a seawater density to a “sigma-t” value.
Sigma-t (σt): is the oceanographer’s method of accurately representing seawater density to 5th decimal place

σ= (density -1 ) x 100
What primarily “drives” the deep ocean currents?
a) prevailing winds [easterlies (tropics/trade winds) or westerlies (midlatitudes)]

b) wind circulating around a moving ocean storm center
What is the “thermohaline circulation?”
Processes that increase the water’s density at the surface cause density-driven vertical circulation. This overturn may reach only shallow depths or extend to the deep-sea floor, ensuring an eventual top-to-bottom exchange of water. Because the density is normally controlled by surface changes in temperature and salinity, this vertical circulation is often called thermohaline circulation.
What are the benefits of “upwelling” and “downwelling” to sea life?
Downwelling transports oxygen-rich surface water to depth for the deep-living animals. Upwelling returns low oxygen-content water with dissolved, decay-produced nutrients to the surface, where the nutrients acts as fertilizers to promote photosynthesis and the productions of more oxygen in the sunlit waters.
What primarily “drives” the surface ocean currents?
Surface ocean currents are set into motion by the prevailing large atmospheric surface circulation (winds)
What is a “gyre?”
In open oceans, surface currents are deflected 45° more to the right in the NH and more to the left in the SH
This deflation, when combined with shape and distribution of landmasses creates the observed large circular motion current system, known as gyres
What is the “Ekman Spiral?” Describe “Ekman Transport” in the oceans.
Water’s viscosity causes water in to layer below to move more slowly and therefore be deflected more by the coriolis effect o the right in the NH and to the left in the SH, then in the surface layer.
Same reasoning applies to each successive layer down. The net result is a current spiral in which each successive deeper layer above.
It is named the Ekman Spiral. It is observed down to approximately 100 to 150 meters, where the highly reduced current is opposite to the surface current.
Deep average flow in the Ekman Spiral called Ekman Transport, is at 90° to the right in the NH and left in the SH with respect to the surface wind.
Understand the process of “upwelling” and “downwelling.”
Downwelling- areas of thermohaline circulation where water converges and sinks
Upwelling- areas of diverging rising waters
What are the biological benefits to upwelling and downwelling in the oceans?
Upwelling DZ brings nutrient to the ocean surface, so they are excellent fishing areas.
In costal regions, a downwelling CZ brings Oxygen down, and can change to an upwelling DZ on seasonal basis. The wind alters its directions.
What is the “Sargasso Sea” and where is it located?
The Sargasso Sea is located in the center of the N. Atlantic Ocean gyre, in what is called the horse latitudes for its deadly calms.
What is the primary generating force and restoring force of large ocean waves?
Generating forces: Wind, large atmospheric storms, ocean currents
Restoring forces: Surface tension, gravity
Know what makes a wave a “deep water wave” or a “shallow water wave.”
Deep water waves occur in water whose depth exceeds half the wavelength of the wave D > L/2
Shallow water waves: when waves propagate into water depth less than half of the wavelength, they begin to feel the bottom and slow down
Where water depth decrease to less then L/20, waves are shallow water waves
Know how to measure the wavelength, period, height and amplitude of a wave.
Wavelength- Crest to Crest
Period- time required for two successive crests to pass a point in space.
Height- Crest to Trough
Amplitude- Water Level to Crest or Water Level to Trough