Oceanography Final
The islands bordering the deep-sea trenches
are explosive volcanoes that emit andesite lavas
Fishing is a growth industry, but the fishing consortia are, for the most part, careful to conserve this resource and not to exceed the maximum sustainable yield.
false.
Some species are brightly bioluminescent.
dinoflagellate
The mid-ocean ridges are recognized as:
divergent plate boundaries.
Seaweeds are of great interest to marine biologists, but have no commercial value.
false.
Where, through a year, is the greatest total oceanic primary productivity?
in the temperate zones.
Arrive in the ocean from continents via rivers.
Terrigenous sediments.
The most abundant sediment in the ocean.
Terrigenous sediments.
The force driving the crustal plates is believed to be:
Convection cells in the upper mantle and the tug of the descending plates.
The concept of "Law of the Sea" is a modern one, having evolved after the First World War.
False
Submarine canyons occur:
Near the edges of ocean basins associated with continental shelves and slopes.
Carbonate sediments are rare in deep sea sediments because:
The carbonate shells dissolve in deep water.
Which of the following statements accurately describes continental margins?
They are areas of frequent earthquakes and volcanoes, where crustal plates are converging or are in collision.
Which of the following statements applies to resources from the sea?
They are more dilute, harder to reach, and more difficult to recover.
What is the name of the outermost solid layer of Earth?
lithosphere
The trailing edge of a moving continental crustal plate is most likely to exhibit features associated with
passive continental margins.
Which is greater, the average height of the continents or the average depth of the ocean?
the average depth of the ocean.
The great heaps of unconsolidated sediment at the base of the continental slope are known as:
the continental rise.
The transition between the shelf and the deep seafloor is
the continental slope and rise.
In volume and quantity, most marine sediments are associated with:
the continental slopes and rises.
Most of the world ocean has the temperature properties of
the deep and bottom waters.
Which is greater, the height of the world's tallest mountain or the depth of the world's greatest trench?
the depth of the trench (Challenger Deep).
The upper sunlit layer of the ocean is called __________ and extends to a depth of about ____________ :
the photic zone ... 100 meters
Generally the fastest and deepest ocean currents are:
western boundary currents.
The immediate source of most of the energy for ocean currents is:
wind.
Animals.
zooplankton
About ____% of the crude oil used by humans is derived from the seabed.
35
About ____% of human food comes from the sea.
4
When carbon dioxide dissolves in water, the water becomes slightly more
acidic, its pH is lower.
What is produced in primary productivity?
carbohydrates
In photosynthesis, the energy of sunlight ultimately rests in
carbohydrates.
Primary productivity can be measured from satellites by sensors that detect
chlorophyll concentrations.
The more efficient photosynthesizer of the two plants listed.
diatom
Two valves, or shells, of glass-like substance.
diatom
Flexible outer covering.
diatom and or dinoflaggelate?
HABs or "red tides" are usually caused by these.
diatoms and or dinoflaggelates?
In order to survive, every organism must have a continuous external source of:
energy.
Plant-like organisms.
phytoplankton
Drifting with the currents.
plankton
The organisms that produce food are called:
primary producers
The zone of lighted ocean in which marine autotrophs tap more energy than they use to stay alive is called:
the euphotic zone
The only marine energy source being successfully exploited on a large scale is:
tidal currents
The average width of the continental shelves is about ____ kilometers (____ miles).
67...(42)
The worldwide fish catch is presently valued at about ____.
90-100 billion dollars.
If two oceanic plates collide at a relatively fast speed, and one is much older and cooler (therefore denser) than the other, what will probably happen?
A trench will form and Large earthquakes will occur.
The ocean is stratified with respect to
All of the above: density. Temperature. Salinity.
The ocean's deep sound channel (sofar layer) is characterized as a zone in which:
All of the above: sound is horizontally concentrated rather than diffused as it moves through the water. acoustical energy losses are relatively small. sound waves travel great horizontal distances. sound velocity is at a minimum.
Can be used to learn about seabed age and history.
All of these: Terrigenous sediments. Biogenous sediments. Hydrogenous (or authigenic) sediments. Cosmogenous sediments.
Land-based evidence for plate tectonics can be seen in:
All of these: the distribution of Glossopteris flora and fauna. evidence of ancient glaciations.the alignment of mountain ranges.the correlation of rocks in now widely separated continents.
The only ocean current that continues in an uninterrupted circle around the circumference of the Earth without encountering land is the:
Antartic Circumpolar Current.
Earth's oldest rocks are found:
At the cores of the continents.
In general, continental shelves tend to be wider in the
Atlantic ocean, because its margins tend to be passive.
Comprises the actual seafloor (beneath the sediments).
Basaltic rock (sima)
Why is the inside of Earth still hot?
Because the decay of large radioactive elements is creating heat in Earth's inner layers.
Of organic origin; i.e., made by organisms.
Biogenous sediments.
Oozes.
Biogenous sediments.
The sediment that covers the greatest area of seabed
Biogenous sediments.
A "mystery" in our understanding of plate tectonics has been, until recently, the nature of the power source capable of moving the plates and the continents embedded within them. Recent evidence indicates the power source to be:
Convection currents within Earth's mantle is moving the plates.
The Earth's rotation influences currents by a force [or acceleration, to be correct] known as:
Coriolis effect.
Of extraterrestrial origin.
Cosmogenous sediments.Cosmogenous sediments.
The deep-sea floors probably contain even more oil and natural gas than the continental shelves. These zones have not been exploited only because of the difficulty in drilling in these areas.
False
The world's catch of seafood is made up of what kinds of organisms?
Herring, anchovies, and sardines.
Generated in place, on the spot where we find them.
Hydrogenous (or authigenic) sediments.
New crust is being generated:
In the rift valleys of the mid-ocean ridges.
The tonnage of fish caught has changed in what way?
It has increased somewhat since about 1980 due to better fishing boats, the application of high technology, and increased demand.
The per capita world fish catch has changed in what way?
It increased steadily to about 1970, then declined.
The transmission of sound by water can best be described by which of the following statements:
It is more efficient than transmission by air.
Which of the following statements relates to mariculture as it has developed in the United States?
It is used primarily for raising lobsters, abalone, and other high-priced food products.
Although 99% of the ocean floor is unexplored, have people reached essentially the deepest spot in the ocean and returned safely to the surface?
Yes, but it was some while ago, in the 1950s.
A system of four currents completing a flow circuit around the periphery of an ocean basin is collectively called:
a gyre.
A zone in which the ocean's salinity increases rapidly with increasing depth is called:
a halocline
Hydrothermal springs seem to be located near:
active areas of seafloor spreading.
The formation of crude oil will occur in an environment that provides
all of the above.
Submarine canyons are
all of the above: found worldwide, on all kinds of shelves. steep-walled and narrow. cut into firm rock. cut into the shelf and may extend almost to the shore.
Which current within a Northern Hemisphere gyre would you expect to have the lowest salinity and temperature?
an eastern boundary current.
Kelp, or common seaweed, is in this group:
brown algae, the Phaeophyta.
Currents tend to move in great _______________ patterns in the northern hemisphere.
clockwise.
San Francisco's characteristic cold and foggy weather is caused by a:
cold eastern boundary current.
The densest seawater is the:
coldest and saltiest.
The most dense water in ocean currents is the
coldest and saltiest.
The landscape of the seafloor would best be described as
containing ridges, trenches, seamounts, and other features different from those found on land.
Propelled by twin whip-like projections.
dinoflagellate
The organisms that consume autotrophs are called:
heterotrophs.
The best fishing grounds are located
in temperate waters over continental shelves.
The continental shelf
is a gently sloping platform with a variable landscape.
If our planet were without its ocean, but otherwise the same as it is today, would surface temperatures be more extreme than they are now (that is, higher high temperatures in summer, and lower low temperatures in winter), of less extreme, or what?
more extreme.
The main inorganic nutrients necessary for the success of marine autotrophs are:
nitrates and phosphates.
The group of marine algae best adapted to deep water is:
red algae, the Rhodophyta.
The ultimate source of most of the energy for ocean currents is:
the sun.
The most pronounced thermoclines exist in:
the tropics.
The greatest amount of marine energy is theoretically available from
thermal gradient
The ocean tends to become more dense with increasing depth:
true
Marine algae are non-vascular plants.
true.
