Oceans And Coasts Ch. 18

Front 1

abyssal plain

Back 1

a broad, relatively flat region of the ocean that lies at least 4.5 km below sea level

Front 2

active continental margin

Back 2

a continental margin that coincides with a plate boundary

Front 3

backwash

Back 3

the gravity-driven flow of water back down the slope of a beach

Front 4

barrier island

Back 4

an offshore sand bar that rises above the mean high-water level, forming an island

Front 5

bathymetry

Back 5

variation in depth

Front 6

beach

Back 6

a gently sloping fringe of sediment along the shore

Front 7

beach drift

Back 7

the gradual migration of sand along a beach

Front 8

beach face

Back 8

a steeply concave part of the foreshore zone formed where the swash of the waves actively scours the sand

Front 9

beach nourishment

Back 9

trucking or shipping in vast quantities of sand to replenish a beach that has eroded

Front 10

berm

Back 10

a horizontal or landward-sloping terrace in the backshore zone of a beach that receives sediment during a storm

Front 11

bioturbation

Back 11

the mixing of sediment by burrowing animals such as clams and worms

Front 12

center of mass

Back 12

the point within an object, or a group of objects, about which mass is evenly distributed

Front 13

centrifugal force

Back 13

the apparent outward-directed force that material on or in an object feels when the object moves in orbit around a point

Front 14

coast

Back 14

the region where the land meets the sea, and where over 60% of the global population lives today

Front 15

coastal wetland

Back 15

a vegetated, flat-lying stretch of coast that floods with shallow water but does not feel the impact of strong waves

Front 16

continental shelf

Back 16

a broad, shallowly submerged region of a continent along a passive margin

Front 17

coral reef

Back 17

a mound of coral and coral debris forming a region of shallow water

Front 18

Coriolis effect

Back 18

the deflection of objects, winds, and currents on the surface of the Earth owing to the planet's rotation

Front 19

current

Back 19

1) a well-defined stream of ocean water; 2) the moving flow of water in a stream

Front 20

Earth-Moon system

Back 20

refers to this pair of objects viewed as a unit, as they move together through space

Front 21

estuary

Back 21

an inlet in which seawater and river water mix, created when a coastal valley is flooded because of either rising sea level or land subsidence

Front 22

fjord

Back 22

a deep, glacially carved, U-shaped valley flooded by rising sea level

Front 23

gravitational pull

Back 23

the attractive force that one mass exerts on another

Front 24

guyot

Back 24

a seamount that had a coral reef growing on top of it, so that it is now flat-crested

Front 25

gyre

Back 25

a large circular flow pattern of ocean surface currents

Front 26

lagoon

Back 26

a body of shallow seawater separated from the open ocean by a barrier island

Front 27

longshore current

Back 27

a current that flows parallel to a beach

Front 28

organic coast

Back 28

a coast along which living organisms control landforms along the shore

Front 29

passive continental margin

Back 29

a continental margin that is not a plate boundary

Front 30

pelagic sediment

Back 30

microscopic plankton shells and fine flakes of clay that settle out and accumulate on the deep-ocean floor

Front 31

reef bleaching

Back 31

the death and loss of color of a coral reef

Front 32

rogue wave

Back 32

defined as waves that are more than twice the size of most large waves passing a locality during a specified time interval

Front 33

sandspit

Back 33

an area where the beach stretches out into open water across the mouth of a bay or estuary

Front 34

seamount

Back 34

an isolated submarine mountain

Front 35

submarine canyon

Back 35

a narrow, steep canyon that dissects a continental shelf and slope

Front 36

swash

Back 36

the upward surge of water that flows up a beach slope when breakers crash onto the shore

Front 37

thermohaline circulation

Back 37

the rising and sinking of water driven by contrasts in water density, which is due in turn to differences in temperature and salinity; this circulation involves both surface and deep-water currents in the ocean

Front 38

tide

Back 38

the daily rising or falling of sea level at a given point on the Earth

Front 39

tide-generating force

Back 39

the force, caused in part by the gravitational attraction of the Sun and Moon, and in part by the centrifugal force created by the Earth's spin, that generates tides.

Front 40

wave base

Back 40

the depth, approximately equal in distance to half a wavelength in a body of water, beneath which there is no wave movement

Front 41

wave refraction (ocean)

Back 41

the bending of waves as they approach a shore so that their crests make no more than a 5 degree angle with the shoreline

Front 42

wave-cut bench (platform)

Back 42

a platform of rock, cut by wave erosion, at the low-tide line that was left behind a retreating cliff

Front 43

wave-cut notch

Back 43

a notch in a coastal cliff cut out by wave erosion