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GEOSC 040 Quiz 1

Terms in this set (67)

What is the "Goldilocks Principle" as applied to Earth and the Oceans?
Earth had just the right position in the solar system to allow retention of liquid water and habitability for life. It is neither too close to nor too far from the Sun. It also suggested that when it was forming, Earth had just the right mass, large enough to retain water.
Which is greater - the average depth of the ocean, or the average elevation of the continents?
The average depth of the ocean.
Why do we say there is one world ocean?
We say there is one world ocean because all of the oceans are "connected."
Over time, does water from the Atlantic and Pacific Oceans mix with waters from the Baltic and Mediterranean seas?
Yes, due to ocean currents.
Surface water on Earth most likely came from where?
From the deep ocean, from rain, runoff, and other sources.
How is Ocean deep water different from shallow water?
It has different salinity, temperature, chemical composition, and density. Deep water is colder, saltier, and therefore, denser than surface water.
Why is water a polar molecule?
The angular shape of the water molecules make it polar. Each molecule has a positive end and a negative end, because protons are left partially exposed when the negatively charged electrons bond more closely to oxygen. The polar water molecule acts something like a magnet, each end attracting oppositely charged particles (positive attracts negative, and vice versa.) When water comes into contact with the compounds the elements of which are held together by attraction of opposite charges, the polar water molecule will separate that compound's elements from each other (dissolving compounds, such as salt.)
What properties of water derive from its polar nature?
Cohesion, adhesion, the blue "tint" of water, very high heat capacity, liquid at room temperature, and solid state (ice) less dense than in liquid form.
What did Rachel Carson suggest about how ocean chemistry may have changed over geologic time (millions of years)?
She suggested that ocean chemistry may have changed over geologic time due to rain and other factors which weather the continents bring run-off and other sources of water back to the ocean. Also, pollution has a factor in the chemistry of the oceans. With these factors, came new chemicals changing the composition of the ocean.
What did she think about the connections between river chemistry and ocean chemistry?
She believed that rivers deliver dissolved rock (including elements such as Na, Ca, and Cl) to the world ocean, which would cause changes in ocean chemistry through time.
How did geosc040 get it's name "The Sea Around Us"?
From Rachel Carson's book of the same title.
What affect does photosynthesis have on the concentrations of CO2 and O2 in seawater?
Because plants and plantlike organisms require carbon dioxide for photosynthesis and metabolism, surface CO2 concentrations tend to be low while 02 concentrations are high. A decrease in oxygen below the sunlit upper layer usually results from bacteria and marine animal respiration which leads to higher carbon dioxide concentrations. Oxygen levels are slightly higher in deeper water because fewer animals are present to take up oxygen reaching these depths because oxygen-rich polar water that sinks from the surface is the greatest source of deep water.
How do the concentrations of CO2 and O2 vary with depth in the oceans?
Carbon dioxide concentrations increase with increasing depth, but oxygen concentrations usually decrease through the mid-depths and then rise again towards the bottom.
How is heat different than temperature?
Heat is energy produced by random vibrations of atoms or molecules, a measure of how many molecules are vibrating and how rapidly they are vibrating. Temperature is an object's response to the input of removal of heat, records only how rapidly the molecules of a substance are vibrating.
What is heat capacity?
Heat capacity is a measure of the heat required to raise the temperature of 1 gram of a substance by 1 degree Celsius.
What is latent heat?
Latent heat is the heat needed to change phases or state of a substance. Ex. water to ice. Latent heat of fusion - 80cal/1gram at 0 degrees Celsius. Latent heat of vaporization - 540cal/1gram at 20 degrees Celsius.
What's the difference between sensible heat and latent heat?
Sensible heat describes temperature changes via heat capacity, is the detectable increase or decrease in heat.
How does the addition of salt to water change the freezing (boiling) point of water?
It will decrease it's freezing point, but will increase it's boiling point.
What is residence time of an element in seawater?
It is the average length of tie an element spends in the ocean.
How do you calculate time?
Using the equation: (amount of element in the ocean) divided by (the rate at which element is added to/removed from the ocean).
How do temperature and salinity influence the solubility of gas in seawater?
Gases increase as temperature falls and salinity rises, and decrease as temperature rises and salinity falls.
Why does ice float?
The density of liquid water is higher than that of ice which is why ice floats.
How is the ocean stratified by density?
The least dense water on top and the most dense water on the bottom.
What physical factors are involved?
Because water has low viscosity, denser water masses sink to the bottom, whereas less dense water masses lie nearer the surface. Also, deep water masses has a rather narrow range of temperature & salinity while most variability in T&S occurs in surface or near-surface waters.
What names are given to the ocean's density zones?
Surface Zone, Pycnocline, and Deep Zone.
What are the thermocline, pycnocline, and halocline?
Depth ranges in the ocean.
Are they related to temperature, salinity, and density of seawater?
Thermocline - temperature, Halocline - salinity, and Pycnocline - density of seawater.
Are they the same in all places in the ocean?
No, there is typically no pycnocline in high latitudes because there's little difference in density.
What are the main factors that influence plankton blooms?
abundance, nutrients, sunlight, the right temperature, and cysts.
Without sunlight, the phytoplankton would be unable to....?
photosynthesize and unable to multiply in number.
As ocean water has warmed over the past decade...?
the number of red tides has increased.
As the Earth rotates on its axis...?
points at different latitudes rotate at different velocities.
While all points have the same rotational velocity (all rotate once per day)...?
they have different linear velocities (distance traveled per day).
The Coriolis Effect
explains that any freely moving object at or above the Earth's surface that moves horizontally through a long distance for a relatively long period of time will appear to veer to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
The magnitude of this "effect" increases with...?
the velocity and latitude of the object.
The Coriolis "Force" increases with...?
latitude: it is 0 at the equator and highest at the poles.
The primary factor affecting the amount of deflection is....?
the length of time a particle is in motion, meaning even at low latitudes, a large Coriolis deflection is possible if an object is in motion for a long time.
What are the connections between large scale wind patterns and the pattern of surface ocean circulation?
Most of Earth's surface wind energy is concentrated in each hemisphere trade winds, (easterlies & westerlies). Waves on the sea surface transfer some of the energy from the moving air to the water by friction. This tug of wind on the ocean surface begins a mass flow of water. The water flowing beneath the wind forms a surface current.
Ocean surface circulation is drive primarily by...?
the global wind system. Winds induce drag on surface waters by friction at the interface, imparting both direction and speed to surface waters.
Higher wind speeds produce...?
faster surface currents.
The Coriolis Effect modifies...?
wind (and current) directions on the rotating Earth.
What is a gyre?
Continents and basin topography often block continuos flow & help deflect the moving water into a circular pattern. A gyre is a circuit of mid-latitue current around the periphery of an ocean basin.
Most recognize how many gyres?
5 as well as the Antarctic Circumpolar Current.
What factors determine the large-scale wind patterns and the patterns of ocean circulation in the North Atlantic?
the balance of wind energy, friction, the Coriolis Effect, and the pressure gradient propels gyres and holds them along the outside of ocean basins.
Are there any differences between the surface flow on the Eastern and Western side of ocean basins?
Yes, the pileup of water in the rotating gyre is NOT symmetric in the center of the gyre. The highest surface elevations are located nearer to the western boundary of the gyre. The velocity of the generally northward-flowing currents along the western margin of the gyre is greater than the southward-flowing currents on the eastern margin of the gyre.
Why are these difference caused?
by the Coriolis Effect
What are the similarities and differences between gyres and large scale ocean currents in the northern and southern hemispheres?
There are several different kinds of large scale ocean currents. Gyres consist of currents that blend into one another. Flow is continuos, without obvious places where one current ceases and another begins.
What are main cells?
The main cells are Hadley Cells (Northeasterly & Southeasterly Trades), Ferrel Cells (Westerlies), and Polar Cells.
Why do they produce a regular pattern of low and high pressure at specific latitudes?
because of the Coriolis Effect - air turns to the right in the NH and to the left in the SH.
Why do winds generally come from the East for the locations from 30 Degrees S to 30 Degrees N?
When air has traveled from the equator to the pole (30DS & 30DN) the air becomes dense enough to fall back toward the surface. In the NH, the Coriolis deflects surface air to the right & the air blows across the ocean/land from the Northeast.
What is the general pattern of heating on Earth, averaged over a year?
Warm water flows to higher latitudes, transfers heat to the air & cools, moves back to low latitudes, and absorbs heat again; then the cycle repeats.
Is it random or is there a systematic variation as a function of latitude?
There is a systematic variation as a function of a latitude.
What are the main factors that determine how heat is transported from low to high latitudes?
heat is transported from the tropics to higher latitudes by ocean and atmosphere to partially compensate from uneven heating of the earth.
Latent Heat Transfer:
is more important than sensible heat transfer. It involves a transfer of energy to an airmass from the ocean, which is gained as heat when vapor condenses from the airmass as it cools later on.
Ekman Spiral:
explains that water at sea surface moves at an angel to the wind direction. A humongous column of water is being set in motion by wind blowing across its surface. The Coriolis Effect causes the surface current to move at 45 degrees in the NH or the SH. This layer sets the layer beneath into motion by friction passing the wind down and making each layer have a lower velocity/transport direction. The water movement moves at right angles to the direction of the wind.
What makes water sink from the surface and become deep water?
Density makes water sink from the surface and become deep water.
How does deep water circulation play a role in heat transfer and global circulation?
As temperature drops, the density of sea water increases until it exceeds the density of the water below. At this point, the surface water sinks and begins to travel around the ocean basins where it is upwelled to the surface. This deep circulation is part of the mechanism for transferring heat from low to high latitudes.
What do temperature, salinity, and density curves look like in the tropics vs the mid-latitudes vs the polar regions?
The tropics have the lowest density, with moderately warm water and low salinity. The mid-latitudes have a density in the mid-range with relatively cool water and salinity. Polar regions are typically very dense, with extremely low temperatures and high salinities.
What is the photic zone and why is it important?
the thin film of lighted water at the top of the surface zone. it is important because it is where all of the production of food by photosynthetic marine organisms take place. here, water is heated by the sun, transferred from the ocean in to the atmosphere & space, gases are exchanged with the atmosphere and most of the ocean's life is found here.
Do all wavelengths penetrate sea water in the same way?
NO, shorter (blue) wavelengths penetrate deeper than longer (red) wavelengths. The energy of some colors of light is converted into heat or absorbed nearer to the surface than energy of other light colors. Clear ocean water looks blue because blue light can travel through water far enough to be scattered back through the surface to our eyes while the other colors are absorbed relatively quickly.
Why is photosynthesis important in oceans?
because it provides the basis for "food chains" in the marine realm and produces the organic matter which is the source of energy for nearly all other ocean life.
How does photosynthesis affect the concentration of dissolved gases in the ocean?
Photosynthesis plants and animals consume carbon dioxide and produce oxygen.
Why is mixing of deep waters in surface waters important for life in the oceans?
because this water is often rich in nutrients that marine organisms need for growth.
What role do bacteria play in the oceans?
Organic matter is consumed by animals & plants through respiration supporting their growth. Nutrients must be "recycled" -excreted by animals, "regenerated" by bacteria- to be reused by plants.
If there were no bacteria in the oceans, what effect would that have on the amount of carbon that got buried in sediments at the bottom of the ocean?
organic matter could not be broken down and there would be an abundance of carbon sediments.
What are the major groups of phytoplankton?
Diatoms, Coccolithophorids, and Dinoflagellates.
What are the main factors that influence season variations in phytoplankton?
seasonal changes of light (sun angle/hours of daylight), seasonal changes in water-column stability (more stability, less nutrients mixed to the surface, and predator/prey interactions), and changes in "grazing" by zooplankton.
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