Oceanography Final Exam – Flashcards
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What percent of the Earth's surface is covered by oceans?
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71%
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What are the two most abundant gases in the atmosphere? What is the percentage of each by volume?
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78% nitrogen, 21% oxygen
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Water moves from surface of Earth into ground
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Infiltration
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What is the 2nd largest reservoir in the hydrosphere, and where is it located?
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Glacial ice, Antarctica, Greenland
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Mostly granitic, thicker and less dense
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Continental crust
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Mostly basalt, is thinner and denser
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Oceanic crust
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Movement of the seafloor away from a mid-ocean ridge
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Seafloor spreading
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What is the driving force behind continental drift?
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Convection in the Earth's mantle
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Who proposed the idea of continental drift?
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Alfred Wegener and Frank B. Taylor
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What type of lithosphere is created at a divergent plate boundary?
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Oceanic crust
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Lava that cools rapidly on the ocean floor
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Pillow basalt
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Substance that precipitates from hydrothermal vent waters; accumulate as dark clouds and accumulate in the form of conical chimneys
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Black smoker
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What is an example of a divergent plate boundary?
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Mid-Atlantic Ridge
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What happens to the age of the ocean floor, the depth, and the heat flow from the mantle as you move away from a mid-ocean ridge?
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Age increases, depth increases, heat flow from mantle decreases
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How fast is the spreading rate of the East Pacific Rise compared to the Mid-Atlantic Ridge?
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Almost ten times faster
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How does an island arc form?
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Melting of subducting plates
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Where does an oceanic trench develop?
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Where two colliding plates meet
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What are two examples of oceanic-oceanic convergent plate boundaries?
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Aleutian Islands, Japan
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What two metals increase the density of the oceanic plate?
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Iron and magnesium
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How does a continental arc form?
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Volcanic activity and subduction
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What are two examples of an oceanic-continental convergent plate boundary?
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Andes Mountains, Cascades
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What is an example of a continental-continental convergent plate boundary?
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Himalayas
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What is an example of a transform plate boundary?
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San Andreas Fault
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Which types of plate boundaries are associated with earthquakes?
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All of them
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What type of plate boundaries are not associated with volcanoes?
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Transform plate boundary, continental-continental convergent plate boundary
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In any sample of seawater, from anywhere in the world, what % of the salt accounts for sodium chloride?
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86%
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What is the principle component of most beach sand?
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Quartz
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Which organisms are silica-based?
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Diatoms and radiolarians
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Which organisms are calcium carbonate-based?
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Coccolithophores and foraminifera
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Where do radiolarian-rich deposits form?
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Equatorial latitudes
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Sediment precipitated from seawater
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Hydrogenous sediment
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Black nodules containing manganese, copper, iron, cobalt, and nickel
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Manganese nodules
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Where in the ocean would you not find manganese nodules?
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Arctic
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Tiny sphere of calcite that precipitates out of seawater
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Oolith
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How big are ooliths?
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0.5 to 1.0 mm
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Formed from a rock that was hit by a meteorite, then melted, then cooled back into the rock
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Tektite
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In the continental margin
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Neritic
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30% calcareous organisms
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Calcareous ooze
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Which organisms make up a calcareous ooze?
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Foraminifera and coccolithophores
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How deep is the CCD?
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4500 m
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30% silica organisms
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Siliceous ooze
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Which organisms make up a siliceous ooze?
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Diatoms and radiolarians
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Which type of ooze is not inhibited by depth?
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Siliceous ooze
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Offshore zone that can be used exclusively by the country it is closest to; extends 200 nautical miles
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Exclusive economic zone (EEZ)
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Rock that is less permeable than other rocks such as sandstone; responsible for trapping petroleum
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Reservoir rock
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Where is the 90 degree sun angle on the summer solstice?
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Tropic of Cancer
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Where is the 90 degree sun angle on the spring equinox?
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Equator
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Where is the 90 degree sun angle on the winter solstice?
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Tropic of Capricorn
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Where is the 90 degree sun angle on the autumnal equinox?
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Equator
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What is the tilt of the earth?
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23.5 degrees
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How deep is the photic zone?
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100-200 m
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What are the common greenhouse gases?
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Carbon dioxide and methane
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Develops during daylight hours and blows inland from the ocean in response to differential heating of land and sea
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Sea breeze
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At night, land becomes relatively colder than the sea surface; circulation reverses and a breeze blows offshore
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Land breeze
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Characterized by lots of rain and no wind
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ITCZ
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Characterized by no rain and no wind
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Horse latitudes
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Characterized by lots of rain and very stormy
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Polar front
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Term to describe where there is no precipitation and no wind
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Subtropical anticyclones
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Deep water currents below the pycnocline; much slower than surface currents
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Thermohaline circulation
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What is the driving force behind thermohaline circulation?
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Density differences in the water
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Depth that orbital motion dies out; equals half the wavelength
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Wave base
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Circular path traveled by molecules as a wave passes
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Orbital motion
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Wave in water deeper than its wave base
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Deep-water wave
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The distance the wind blows across an open body of water
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Fetch
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Nearly continuous train of waves breaking along a shore
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Surf
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Time between successive high tides
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Tidal period
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Difference between high tide and low tide
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Tidal range
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How long is a tidal day?
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24 hours and 50 minutes
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Sun, moon, and earth relative to each other form a right angle
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Neap tide
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Sun, moon, and earth relative to each other are linear
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Spring tide
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When does a spring tide occur?
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Full and new moon
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When does a neap tide occur?
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1/4 and 3/4 moons
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Which type of tide has the highest high tide and the lowest low tide?
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Spring tide
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Tidal currents directed toward land, causing water levels to rise in harbors and rivers
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Flood tides
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Tidal currents flowing seaward with falling sea levels
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Ebb tides
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When a flood tide enters a stream or estuary
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Tidal bore
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What is a typical wavelength of a tsunami?
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750 km
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What is a typical wave height in the open ocean (in m)?
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Less than 1 m
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What is the celerity of a typical tsunami?
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645 km/hr
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Transition between land and ocean
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Coast
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Farthest inland extent of storm waves
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Coastline
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Land between low tide line and coastline
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Shore
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Average low tide line
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Shoreline
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Where the sand ends and meets the bedrock under the ocean
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Breaker line
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Breaking wave runs up onto the beach
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Upwash
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Wave flows straight back to the ocean
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Backwash
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Upwash and backwash together
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Swash
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Waves strike the beach at an angle, backwash leaves the beach, and together, the swash makes a zigzag path down the beach
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Longshore current
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Sand and other things in the water following the same path as the longshore current
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Littoral drift
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Platform of sand that slopes steeply upward
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Berm
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Composed of salt-tolerant plants that colonize shores that are protected from wave action
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Salt marsh
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Salt-tolerant woody trees
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Mangroves
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Bedrock that is surrounded by seawater on 3 sides; wave refraction on each side erodes it
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Headland
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Small island or rock formed from eroding headland
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Sea stack
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Elongate, narrow sand island parallel to coast; separated from coast by lagoon, bay, or estuary
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Barrier islands
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Body of water, separates barrier island from mainland
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Lagoon
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Finger-like ridge of sand or gravel projecting partway across a bay or into a body of water
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Sand spit
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Perpendicular to shore; protects mouth of harbor or stream from closing off due to littoral drift
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Jetty
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Built parallel to shoreline; protects harbor from waves
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Breakwater
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Built perpendicular to shoreline; purpose is to widen beach
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Groin
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Concrete or rock embankment; protects beaches, roads, and buildings from waves
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Seawall
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Where do tropical cyclones develop?
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5 to 20 degrees N or S of the equator
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Extremely high waves that can flood cities or barrier islands
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Storm surge
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What is the minimum wind speed for a tropical cyclone to be classified as a hurricane?
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119 km/hr
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Center of the hurricane; winds calm, little or no rain, skies clear
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Eye
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Most intense part of the hurricane; highest winds, heaviest rain
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Eyewall
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Hurricane in the Indian Ocean
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Cyclone
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Hurricane in the West Pacific
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Typhoon
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Low air pressure
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Tropical disturbance
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Wind speeds of 23 mph
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Tropical depression
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Wind speeds of 39 mph
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Tropical storm
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Wind speeds of 74 mph
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Hurricane
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When is a storm assigned a name?
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When it reaches wind speeds of 39 mph
