X
1)
You are on an oceanographic expedition and decide to make a port stop at 3o S, 40o W.
a) [1 pt] X.
b) [1 pt] Circle.
c) [2 pts] 33 degrees*60 miles per degree = 1980 miles
d) [1 pt] Star.
e) [3 pts] No, because the distance for 1 degree of longitude (E-W) varies continuously with
latitude, whereas the distance for 1 degree of latitude is constant with longitude. This is
because the earth is a sphere. Therefore, 1 degree of longitude ≠ 60 naut. miles except at the
equator. Note that you can calculate distance in nautical miles between any two points on the
Earth using spherical geometry and trigonometry.
* No credit for simply restating the question.
* Partial credit if there was any statement that spacing or distance between two lines of longitude
varies with latitude or N-S position.
* Additional resource on latitude, longitude and nautical miles:
http://www.coastalnavigation.com/samples/sec_1/1_pages/1_2.htm
2) on A, 3) on B [2 pts] Factors that affect the density of a fluid:
Any two of the three listed:
[1 pt] Temperature
[1 pt] Chemical composition
[1 pt] Pressure
Partial credit given for:
[0.5 pts] Heat
[0.5 pts] Salinity/ionic content
[0.5 pts] Humidity/water vapor
[0.5 pts] Altitude/depth
3) on A, 6) on B [2 pts] Processes that transport heat:
Ocean surface currents [1 pt]
Atmospheric Convection [1 pt]
Mantle Convection [0.5 pts]
4) on A, 7) on B [2 pts] Process that transfers heat from the ocean to the atmosphere:
Evaporation
5) [2 pts] Property of water is responsible for this difference in temperature range?
Specific Heat
6) on A, 4) on B [2 pts] Oxygen is a non-conservative constituent
7) [2 pts] Two major processes that result in sea level rise.
[1 pt] Thermal expansion of water
[1 pt] Melting of terrestrial ice (ice sheets, glaciers, icebergs)
8) [4 pts] Describe how the concentrations of CO2, H+ and CO32- in surface oceans have changed
since 1750.
[1 pt] Anthropogenic CO2 is discharged to the atmosphere. From there it dissolves in the ocean
surface. The ocean and the atmosphere exchange gas with one another. CO2 increases in surface
waters.
CO2 dissolved in ocean surface waters forms H2CO3 (carbonic acid), which then dissociates to
form H+ (hydrogen ion) and HCO3- (bicarbonate ion). The concentration of each of these ions is
pH dependent.
[1 pt] The resulting increase in H+ lowers the pH to create more acidic conditions.
[1 pt] Comparing pH of 8.1 with pH 7.9 or 8, CO32- decreases in concentration.
9) [2 pts] Why is there more CO2 in the North Atlantic Ocean?
[1 pt] CO2 is more soluble in cold water, so more of it dissolves in high-latitude surface waters
than dissolves at lower latitudes.
[1 pt] The North Atlantic is a location where surface water is sinking. This allows penetration of
CO2 enriched water to greater depth than at lower latitudes.
[0.5 pt] More land and more pollution in N. hemisphere. This is not a correct explanation, but
partial credit was given.
10)
a) [2 pts] Plate boundary?
Convergent (Destructive) or plate boundary
[1 pt] Active plate boundary
[1 pt] Ocean-Ocean plate boundary
b) [2 pts] Tectonic process?
Destructive, convergent; subduction
[1 pt] for description without using correct geological terminology
c) [1 pt] Seafloor feature?
[1 pt for either] An oceanic trench or volcanic island arc
d) [3 pts] Older crust is part of which plate? Why?
[1 pt] The Pacific Plate is older.
[1pt] The location of the trench indicates that the Pacific Plate is subducting under the North
American plate. Also acceptable: Description of how trench location or land location shows
which plate is more dense.
[.5] This means that the crust underlying this part of the Pacific plate is denser than that underlying
the North American plate.
[.5] This indicates that it has had a longer time to cool and/or is further from the spreading center.
e) [2 pts] Different from Cascades formation?
It is different in that here oceanic crust is subducting beneath oceanic crust [1pt], rather than under
continental crust[1 pt].
[1 pt] for contrasting land vs. water without a specific description of plate boundaries.
11)
A
A
B
A
C
A
E
A
D
A
a) [2 pts] High (H) atmospheric pressure?
Location E
b) [2 pts] Low (L) atmospheric pressure?
Location A & D
c) [1 pt] Direction of the winds between 0˚ and 30˚?
Easterly
d) [1 pt] Direction of the winds between 30˚ and 60˚?
Westerly
e) [1 pt] Surface water circulates in the gyre: Counter clockwise
f) [1 pt] Garbage patch?
Location E
g) [1 pt] Oceanographic processes at garbage patch?
Convergence
h) [3 pts] What compass direction will water at the surface flow? Why?
Toward the NW [1 pt], 45 degrees [2 pts] to the left of the wind direction in the So. Hemisphere
If no degrees mentioned, but Coriolis (or) water turning left in the So. Hemisphere mentioned [1
pt]
[0.5 pts] if Earth’s rotation mentioned only
i) [3 pts] What compass direction will the net flow of water be directed? Why?
Toward the W [1 pt] , 90 degrees [2 pts] to the left of the wind direction in the So. Hemisphere
If no degrees mentioned, but Earth’s rotation (or) Coriolis (or) water turning left in the So.
Hemisphere mentioned [1 pt]
[0.5 pts] if Earth’s rotation mentioned only
j) [2 pts]
Ocean
Sea Floor
If only a horizontal or a vertical arrow drawn (but not both) [1 pt]
If 1 arrow drawn in atmosphere [1 pt]
If both arrows drawn in atmosphere [0 pts]
Downwelling diagram accepted if water movement SE/E answered above (that would lead to
downwelling) [2 pts.]
k) [1 pt] Upwelling
If diagram depicted downwelling and downwelling circled [1 pt]
l) [6 pts]
Decreased Strength of Trade Winds
Decreased Atmospheric Pressure
Increased Sea Surface Elevation
Increased Precipitation
Decreased Fisheries Production
Increased Sea Surface Temperature