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GEOSC 40 Midterm
Terms in this set (37)
Earth has just the right position in the solar system, not too close to the sun, not too far away from the sun.
Which is greater? The average depth of the ocean or the average elevation of continents?
The average depth of the ocean.
Why do we say there is a one world ocean?
We say this because all oceans are "connected"
Surface water on Earth most likely came from where?
Ice and groundwater; Lakes and rivers; Runoff
How is ocean deep water different than surface water?
Deep water has a different temperature, salinity, and density. Deep water is denser, colder, and has a higher salinity than surface water.
Why is water considered a polar molecule?
The angular shape with dipoles of water makes it a polar molecule.
What did Rachel Carson suggest about how ocean chemistry may have changed over geologic time (millions of years)? What did she think about the connections between river chemistry and ocean chemistry?
She suggested that ocean chemistry may have changed over geologic time due to rain and other factors which weather the continents and 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 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 O2 concentrations are high. The colder the water the more gas is dissolved.
How do the concentrations of CO2 and O2 vary with depth in the oceans?
More O2 in surface waters, less CO2 in surface waters and vice versa.
How is heat different than temperature?
Heat is the total energy of molecular motion in a substance while temperature is a measure of the average energy of molecular motion in a substance.
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.
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. Latent heat is the heat needed to change a phase of a substance.
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 residence 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?
Solubility decreases with increasing temperature and increasing salinity.
Why does ice float in water?
Ice is less dense than the water.
How is the ocean stratified by density?
Density of water increases as you go deeper. Surface water is less dense than deep water.
What names are given to the ocean's density zones?
Surface Zone, Pycnocline, Deep Zone
What is the thermocline?
What is the halocline?
What is the pycnocline?
What are the main factors that influence plankton blooms?
Light, nutrients, carbon dioxide, water.
What is a gyre? What factors determine the large-‐scale pattern of surface ocean circulation in the N. Atlantic sub-‐tropical gyre?
A gyre is a large scale surface current.
What are the similarities and differences between gyres and large scale ocean surface currents in the northern and southern hemispheres?
Coriolis force impacts these currents moving clockwise in the northern hemisphere and counterclockwise in the southern hemisphere.
Large scale pattern of winds. What are the main cells? Why do they produce a regular pattern of low and high pressure at specific latitudes?
Hadley, Ferrel, and Polar. Warm air is centered around the equator and warm air rises.
Why do the winds generally come from the east for locations from 30° S to 30° N?
What is the general pattern of heating on Earth, averaged over a year? Is it random or is there a systematic variation as a function of latitude?
More solar energy is absorbed in the tropics. Heat is then transferred to higher latitudes, until reaching the polar regions and then coming back down with cold air. The polar regions receive the warmer air masses - coldest regions. Absorbs heat again; then the cycle repeats.
What are the main factors that determine how heat is transported from low to high latitudes?
Ocean currents transport heat.
What is the Ekman spiral?
It explains that water at sea surface moves at an angle to the wind direction. The Ekman spiral predicts that the net motion of surface water is 90 degrees to the right of the wind direction in the N. Hemisphere and 90 degrees to the left of the wind direction in the south pacific.
Think about the connection between surface currents and deep water in the ocean. What makes water sink from the surface and become deep water? How does deep water circulation play a role in heat transfer and global ocean circulation? Does Atlantic Meridional Ocean Circulation (AMOC) have anything to do with this? What is AMOC?
There has to be a circulation between the surface and deep waters. When warm water gets heated it increases evaporation which increases density which makes surface waters sink to deep water in a circulation.
What is the photic zone and why is it important? Do all wavelengths of light penetrate seawater in the same way?
It is the thin film of lighted water at the top of the surface zone. It is important because The photic zone is the layer where photosynthesis can still occur because the waves of light still penetrate the water. It is where all 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 and space, gases are exchanged with the atmosphere and most of the ocean's life is found here.
Why is photosynthesis important in the oceans? How does photosynthesis affect the concentration of dissolved gases in the 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.
Why is mixing of deep waters up into surface waters important for life in the oceans?
Because the deep water contains rich nutrients that marine organisms need for growth.
What role do bacteria play in the oceans? 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?
The bacteria take the organic matter and convert it into nutrients which is then recycled into the surface water and reused as nutrients for the phytoplankton and fish.
What are the major groups of phytoplankton?
Diatoms, Coccolithophorids, Dinoflagellates
What are the main factors that influence seasonal 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).
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