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IB Marine Science SL Exam Questions
and Answers
Abyssal Hill - Answer - Small sediment-covered inactive volcano or intrusion of molten rock less than 200 meters (650 ft) high, thought to be associated with seafloor spreading. Abyssal hills punctuate the otherwise flat abyssal plain. Abyssal Plain - Answer - Flat, cold, sediment-covered ocean floor between the continental rise and the oceanic ridge at a depth of 3,700 to 5,500 meters (12,000 to 18,000 ft). Abyssal plains are more extensive in the Atlantic and Indian Oceans than in the Pacific. Active Margin - Answer - The continental margin near an area of lithospheric plate convergence; also called Pacific-type Margin Bathymetry - Answer - The discovery and study of submerged contours. Continental Margin - Answer - The Submerged outer edge of a continent, made of granitic crust; includes the continental shelf and continental slope. Compare Ocean Basin. Continental Rise - Answer - The wedge of sediment forming the gentle transition from the outer (lower) edge of the continental slope to the abyssal plain; usually associated with passive margins. Continental Shelf - Answer - The gradually sloping submerged extension of a continent, composed of granitic rock overlain by sediments; has features similar to the edge of the nearby continent. Continental Slope - Answer - The sloping transition between the granite of the continent and the basalt of the seabed; the true edge of a continent. Epicenter - Answer - The point on Earth's surface directly above the focus of an earthquake. Fracture Zone - Answer - Area of Irregular, seismically inactive topography marking the position of a once-active transform fault Guyot - Answer - A flat-topped, submerged, inactive volcano
Hydrothermal Vent - Answer - A spring of hot, mineral- and gas-rich seawater found on some oceanic ridges in zones of active seafloor spreading. Ice Age - Answer - One of several periods (lasting several thousand years each) of low temperature during the last million years. Glaciers and polar ice were derived from ocean water, lowering sea level at least 100 meters (328 feet). Island Arc - Answer - Curving chain of volcanic islands and seamounts almost always found paralleling the concave edge of a trench. Ocean Basin - Answer - Deep-ocean floor made of basaltic crust. Compare Continental Margin. Oceanic Ridge - Answer - Young seabed at the active spreading center of an ocean, often unmasked by sediment, bulging above the abyssal plain. The boundary between diverging plates. Often called a mid-ocean ridge, though less than 60% of the length exists at mid-ocean. Passive Margin - Answer - The continental margin near an area of lithospheric plate divergence; also called an Atlantic-type margin. Seamount - Answer - A circular or elliptical projection from the seafloor, more than 1 kilometer (0.6 mile) in height, with a relatively steep slope of 20-25 degrees Shelf Break - Answer - The abrupt increase in slope at the junction between continental shelf and continental slope. Submarine Canyon - Answer - A deep, V-shaped valley running roughly perpendicular to the shoreline and cutting across the edge of the continental shelf and slope. Transform Fault - Answer - A plane along which rock masses slide horizontally past one another. Asthenosphere - Answer - The hot, plastic layer of the upper mantle below the lithosphere, extending some 350 to 650 kilometers (220 to 400 miles) below the surface. Convection currents within the asthenosphere power plate tectonics Basalt - Answer - The relatively heavy crustal rock that forms the seabeds, composed mostly of oxygen, silicon, magnesium, and iron. Its density is about 2.9 g/cm^ Body Wave - Answer - A seismic wave that moves through the interior of the earth, as opposed to the earth's surface. Buoyancy - Answer - The ability or tendency to float in water or air or some other fluid.
Echo Sounder - Answer - A device that reflects sound off the ocean bottom to sense water depth. Its accuracy is affected by the variability of the speed of sound through water. Fault - Answer - A fracture in a rock mass along which movement has occurred Granite - Answer - The relatively light crystal rock--composed mainly of oxygen, silicon, and aluminum--that forms the continents. Its density is about 2.7 g/cm^ Hot Spot - Answer - A surface expression of a plume of magma rising from a stationary source of heat in the mantle. Isostatic Equilibrium - Answer - Balanced support of lighter material in a heavier, displaced supporting matrix; analogous to buoyancy in a liquid Lithosphere - Answer - The brittle, relatively cool outer layer of Earth, consisting of the oceanic and continental crust and the outermost, rigid layer of mantle. Lower Mantle - Answer - The rigid portion of Earth's mantle below the asthenosphere Magma - Answer - Molten rock capable of fluid flow; called lava above the ground Magnetometer - Answer - A device that measures the amount and direction of residual magnetism in a rock sample Mantle - Answer - The layer of Earth between the crust and the core, composed of silicates of iron and magnesium. The mantle has an average density of about 4. g/cm^3 and accounts for about 68% of Earth's mass. Mantle Plume - Answer - Ascending columns of superheated mantle originating at the core-mantle boundary Oceanic Crust - Answer - The outermost solid surface of Earth beneath ocean floor sediments, composed primarily of basalt Air Mass - Answer - A large mass of air with nearly uniform temperature, humidity, and density throughout Atmosphere - Answer - The envelope of gasses that surround a planet and are held to it by the planet's gravitational attraction Atmospheric Circulation Cell - Answer - large circuit of air driven by uneven solar heating and the Coriolis effect. Three circulation cells form in each hemisphere
Vilhelm Bjerknes - Answer - (1862-1951) Pioneering Norwegian physicist and discoverer of the nature and formation of extra-tropical cyclones which cause most mid-latitude weather. Climate - Answer - The long term average of weather in an area Gaspard Gustave de Coriolis - Answer - (1792-1843) The French scientist who in 1835 worked out the mathematics of the motion of bodies on a rotating surface (aka Coriolis effect) Coriolis Effect - Answer - The apparent deflection of a moving object from its initial course when its speed and direction are measured in reference to the surface of the rotating Earth. The object is deflected to the right of its anticipated course in the Northern hemisphere and to the left in the Southern hemisphere. The deflection occurs for any horizontal movement of objects with mass and has no effect at the equator. Cyclone - Answer - A weather system with a low-pressure area in the center around which winds blow counter-clockwise in the Northern hemisphere and clockwise in the Southern hemisphere. Not to be confused with a tornado, a much smaller weather phenomenon, associated with severe thunderstorms. Doldrums - Answer - The zone of rising air near the equator known for sultry air and variable breezes extratropical cyclone - Answer - A low pressure, mid-latitude weather system characterized by converging winds and ascending air rotating counterclockwise in the Northern hemisphere and clockwise in the Southern hemisphere. An extratropical cyclone forms at the front between the polar and Ferrel cells. Ferrel Cell - Answer - The middle atmospheric circulation cell in each hemisphere. Air in these cells rises at 60 degrees latitude and falls at 30 degrees latitude. Front - Answer - The boundary between two air masses of different density. The density difference can be caused by differences in temperature and/or humidity. Frontal Storm - Answer - Precipitation and wind caused by the meeting of two air masses associated with an extratropical cyclone. Generally one air mass will slide over or under the other and the resulting expansion of air will cause cooling and consequently rain or snow. Geographical Equator - Answer - 0 degrees latitude, an imaginary line equidistant from the geographical poles. Hadley Cell - Answer - The atmospheric circulation cell nearest the equator in each hemisphere. Air in these cells rises near the equator because of strong solar heating there and falls because of cooling at about 30 degrees latitude.
Thermal Equilibrium - Answer - The condition in which the total heat coming into a system (such as a planet) is balanced by the total heat leaving the system Tornado - Answer - Localized, narrow, violent funnel of fast-spinned wind usually generated when two air masses collide; not to be confused with a cyclone. (The tornado's oceanic equivalent is a water spout) Trade Winds - Answer - Surface winds within the Hadley cells centered at about 15 degrees latitude that approach from the North East in the Northern hemisphere and from the South East in the Southern hemisphere. Tropical Cyclone - Answer - A weather system of low atmospheric pressure around which winds blow counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. It originates in the tropics within a single air mass but may move into temperate waters if the water temperature is high enough to sustain it. Small tropical cyclones are called tropical depressions. Larger ones, tropical storms, and great ones, hurricanes, typhoons, and willi-willis depending on location. Water Vapor - Answer - The gaseous, invisible form of water Weather - Answer - The state of the atmosphere at a specific place and time. Westerlies - Answer - Surface winds within the Ferrel cells centered around 45 degrees latitude that approach from the Southwest in the Northern hemisphere and from the Northwest in Southern hemisphere. Wind - Answer - The mass movement of air Acoustical Tomography - Answer - A technique for studying ocean structure that depends on pulses of low-frequency sound to sense differences in water temperature, salinity, and movement beneath the surface. Antarctic Bottom Water - Answer - The densest ocean water (1.0279 g/cm^3), formed primarily in Antarctica's Weddell sea during Southern Hemisphere winters. Antarctic Circumpolar Current (West Wind Drift) - Answer - The current driven by powerful westerly winds north of Antarctica. The largest of all ocean currents, it continues permanently eastward without changing direction. Caballing - Answer - Mixing of two water masses of identical densities, but different temperatures and salinities, such that the resulting mixture is denser than its components. Coastal Upwelling - Answer - Upwelling adjacent to a coast, usually induced by wind.
Contour Current - Answer - A bottom current made up of dense water that flows around (rather than over) seabed projections. Convergence Zone - Answer - The line along which waters of different density converge. Convergence zones form the boundaries of tropical, subtropical, temperate, and polar areas. Countercurrent - Answer - A surface current flowing in the opposite direction from an adjacent surface current. Current - Answer - Mass flow of water. (the term is usually reserved for horizontal movement). Downwelling - Answer - Circulation pattern in which, surface water moves vertically downward. Eastern Boundary Current - Answer - Weak, cold, diffused, slow-moving current at the Eastern boundary (off the west coast of the continent). Examples include, the Canary current and the Humboldt current. Eddy - Answer - A circular movement of water usually formed where currents pass obstructions, or between two adjacent currents flowing in opposite directions, or along the edge of permanent currents. Ekman Spiral - Answer - A theoretical model of the effect of water on wind blowing over the ocean. Because of the Coriolis effect, the surface layer is expected to drift at an angle of 45 degrees to the right of the wind in the Northern hemisphere and 45 degrees to the left in the Southern hemisphere. Water at successively lower layers drift progressively to the right (North) or left (South), though not as swiftly as the surface flow. Ekman Transport - Answer - Net water transport, the sum of layer movement due to the Ekman Spiral. Theoretical Ekman transport in the Northern hemisphere is 90 degrees to the right of the wind direction. El Nino - Answer - A southward flowing, nutrient poor current of warm water off the coast of Western South America caused by a breakdown of trade wind circulation. ENSO - Answer - Acronym for the coupled phenomena of El Nino and the Southern Oscillation Equatorial Upwelling - Answer - Upwelling in which water moving westward on either side of the geographical equator tends to be deflected slightly poleward and replaced by deep water often rich in nutrients.
Upwelling - Answer - Circulation pattern in which deep, cold, usually nutrient-laden water moves toward the surface. Upwelling can be caused by winds blowing to shore or offshore Western Boundary Current - Answer - Storng, warm, concentrated, fast-moving current at the western boundary of an ocean (off the east coast of a continent). Examples include the Gulf Stream and the Japan (Kuroshio) Current. Westward Intensification - Answer - The increase in speed of geostrophic currents as they pass along the western boundary of an ocean basin. West Wind Drift (Antarctic Circumpolar Current) - Answer - Current driven by powerful westerly winds north of Antarctica. The Largest of all ocean currents, it continues permanently eastward without changing direction. Wind-Induced Vertical Circulation - Answer - Vertical movement in surface water (upwelling or downwelling) caused by wind. C = sqrt(gd) - Answer - Relationship of velocity (C), the acceleration due to gravity (g), and water depth (d) for shallow water waves. C = L/T - Answer - Relationship of velocity (C), wavelength (L), and period (T) for deep- water waves; velocity increases as wavelength increases. Typically measured in meters per second. Capillary Wave - Answer - A tiny wave with a wavelength of less than 1.73 centimeters (0.68 inch), whose restoring force is surface tension; the first type of wave to form when the wind blows. Constructive Interference - Answer - The addition of wave energy as waves interact, producing larger waves. Deep-Water Wave - Answer - A wave in which water deeper than one-half its wavelength. Destructive Interference - Answer - The subtraction of wave energy as waves interact, producing smaller waves. Dispersion - Answer - Separation of wind waves by wavelength (and therefore wave speed) as they move away from the fetch (the palce of their formation). Dispersion occurs because waves with long wavelengths move more rapidly than waves with short wavelengths. Disturbing Force - Answer - The energy that causes a wave to form.
Fetch - Answer - The uninterrupted distance over which the wind blows without a significant change in direction, a factor in wind-wave development. Forced Wave - Answer - A progressive wave under the continuing influence of the forces that formed it. Free Wave - Answer - A progressive wave free of the forces that formed it. Fully Developed Sea - Answer - The theoretical maximum height attainable by ocean waves given wind of a specific strength, duration, and fetch. Longer exposure to wind will not increase the size of the waves. Gravity Wave - Answer - A wave with wavelength greater than 1.73 centimeters (0. inch), whose restoring forces are gravity and momentum Group Velocity - Answer - Speed of advance of a wave train; for deep-water waves, half the speed of individual waves within the group. Interference - Answer - Addition or subtraction of wave energy as waves interact; also called resonance. Internal Wave - Answer - A progressive wave occurring at thee boundary between liquids of different densities. Orbit - Answer - In ocean waves, the circular pattern of water particle movement at the air-sea interface. Orbital motion contrasts with the side-to-side or back-and-forth motion of pure transverse or longitudinal waves. Orbital Wave - Answer - A progressive wave in which particles of the medium move in closed circles Plunging Wave - Answer - A breaking wave in which the upper section topples forward and away from the bottom, forming an air-filled tube Progressive Wave - Answer - A wave of moving energy in which the wave form moves in one direction along the surface (or junction) of the transmission medium (or media). Restoring Force - Answer - The dominant force trying to return water to flatness after formation of a wave. Rogue Wave - Answer - A single wave crest much higher than usual, caused by constructive interference. Sea - Answer - Simultaneous wind waves of many wavelengths forming a chaotic ocean surface. Sea is common in an area of wind wave origin.
Wave Height - Answer - Vertical distance between a wave crest and the adjacent wave troughs Wave Period - Answer - The time it takes for successive wave crests to pass a fixed crest Wave Reflection - Answer - The reflection of progressive waves by a vertical barrier. Reflection occurs with little loss of energy Wave Refraction - Answer - Slowing and bending of progressive waves in shallow waves Wave Steepness - Answer - Height-to-wavelength ratio of a wave. The theoretical maximum steepness in shallow water. Wave Train - Answer - A group of waves of similar wavelength and period moving in the same direction across the ocean surface. The group velocity of a wave train is half the velocity of the individual Wave Trough - Answer - The valley between wave crests below the average water level in a progressive wave. Wavelength - Answer - The horizontal distance between two successive wave crests (or troughs) in a progressive wave Wind Duration - Answer - The length of time the wind blows over the ocean surface, a factor in wind wave development Wind Strength - Answer - Average speed of the wind, a factor in wind wave development Wind Wave - Answer - Amphidromic Point - Answer - A "no-tide" point in an ocean caused by basin resonances, friction, and other factors around which tide crests rotate. About a dozen amphidromic points exist in a world ocean. Aphelion - Answer - The point in the orbit of a satellite where it is farthest from the sun Apogee - Answer - The point in the orbit of a satellite where it is farthest from the main body Astronomical Tide - Answer - The tidal levels and character which would result from gravitational effects, e.g. of the Earth, Sun and Moon, without any atmospheric influences. Diurnal Tide - Answer - A tidal cycle of one high tide and one low tide per day
Dynamic Theory of Tides - Answer - Model of tides that takes into account the effects of finite ocean depth, basin resonances, and the interference of continents on tide waves. Ebb Current - Answer - Water rushing out of an enclosed harbor or bay because of the fall in sea level as a tide trough apporaches Equilibrium Theory of Tides - Answer - Idealized model of tides that considers Earth to be covered by an ocean of great and uniform depth capable of instantaneous response to the gravitational and inertial forces of the sun and moon Flood Current - Answer - Water rushing into an enclosed harbor or bay because of the rise in sea level as a tide crest approaches High Tide - Answer - The high-water position corresponding to a tidal crest. Low Tide - Answer - The low-water position corresponding to a tidal trough Lunar Tide - Answer - Tide caused by gravitational and inertial interaction of the moon and Earth. Mean Sea Level - Answer - The height of the ocean surface averaged over a few year's time Meteorological Tide - Answer - A tide influenced by the weather. Arrival of a storm surge will alter the estimate of a tide's height or arrival time, as will a strong, steady onshore or offshore wind Mixed Tide - Answer - A complex tidal cycle, usually with two high tides and two low tides of unequal height per day Neap Tide - Answer - The time of smallest variation between high and low tides occurring when Earth, moon, and sun align at right angles. Neap tides alternate with spring tides, occurring at two-week intervals. Perigee - Answer - The point in the orbit of a satellite where it is closest to the main body Perihelion - Answer - The point in the orbit of a satellite where it is closest to the sun Semidiurnal Tide - Answer - A tidal cycle of two high tides and two low tides each lunar day, with the high tides of nearly equal height Slack Water - Answer - A time of no tide-induced currents that occurs when the current changes direction Solar Tide - Answer - Tide caused by the gravitational and inertial interaction of the sun and Earth.
Foraminiferan - Answer - Hydrogenous Sediment - Answer - Lithification - Answer - Microtektite - Answer - Mineral - Answer - Neritic Sediment - Answer - Nodule - Answer - Oolite Sands - Answer - Paloeceanography - Answer - Pelagic Sediment - Answer - Piston Corer - Answer - Poorly Sorted Sediment - Answer - Pteropod - Answer - Radiolarian - Answer - Sand - Answer - Sediment - Answer - Siliceous Ooze - Answer - Silt - Answer - Stratigraphy - Answer - Terrigenous Sediment - Answer - Turbidite - Answer - Well-Sorted Sediment - Answer - Absorption - Answer - Conversion of sound or light energy into heat
Active Sonar - Answer - A device that generates underwater sound from special transducers and analyzes the returning echoes to gain information of geological, biological, or military importance Adhesion - Answer - attachment of
