Oceans in motion vocab
abyssal plain
The flat, deep ocean floor. It is almost featureless because a thick layer of sediment covers the hills and valleys.
algae
A small single-celled plant.
amphibious
Able to operate on land and in the water.
aphotic zone
Bottom most layer of the ocean zones, where light does not reach.
atoll
Coral reefs sometimes grow around seamounts that rise above the surface of the ocean. As the seamount sinks or
its peak erodes, the seamount will disappear beneath the water leaving the coral ring.
baleen
large stiff plates that grow down from the gums of the whale’s upper jaw, allow whales to filter feed. Baleen is
made of keratin, the same protein that makes up hair and fingernails, and is strong, yet elastic.
Beaufort Wind Scale
a system developed by a British hydrographer, Sir Frances Beaufort, in 1805 to describe wind force at sea.
benthic environment
the sea floor
benthic life
plants and animals that live on the ocean floor.
blowhole(s)
a single or pair of breathing organs of whales and dolphins on the dorsal (back) surface of their head. At the
surface, they quickly inhale and relax the muscular flap to close it so they can dive.
blue water
waters that lie beyond the coastal shallows (coastal ocean).
coastal downwelling
a type of vertical current that arises when onshore winds (or winds blowing toward the shore) push water toward
the coast. This drives the nearshore surface water down and away from the coast.
coastal upwelling
a type of vertical current that arises when offshore winds (or winds blowing toward the ocean) push water away
from the shore and deep, colder water rises to replace the water that has been blown out into the ocean. This cold
water from deep off the ocean floor brings many nutrients to the surface.
continental margin
is the continental slope, which is still considered part of the continent, together with the continental shelf.
continental rise
as currents flow along the continental shelf and down the continental slope, they pick up and carry sediments
along and deposit them just below the continental slope. These sediments accumulate (gather) to form the large,
gentle slope of the continental rise.
continental shelf break
where the bottom sharply drops off into a steep slope. It usually begins at 430 feet (130 meters) depth and can be
up to 20 km wide.
continental slope
connects the continental shelf and the oceanic crust.
deep ocean basin
is about 2.5 to 3.5 miles deep, covers 30 % of Earth’s surface and has features, such as abyssal plains, deep-sea
trenches and seamounts.
deep-sea trenches
are the deepest parts of the ocean. The deepest one, the Marianas Trench in the South Pacific Ocean, is more than
33,000 feet, or almost 5 miles (8.05 kilometers) deep.
deposition
the buildup of sediment or sand.
diurnal tides
tides that occur once a day. A body of water with diurnal tides, like the Gulf of Mexico, has only one high tide
and one low tide in a 24-hour period.
duration
the length a gust of wind blows.
dysphotic zone
middle layer of ocean zones where light can be measured, sometimes as deeply as a kilometer down, but is too faint to
support photosynthesis.
ebb
tidal currents that are moving away from the beach.
echolocation
a method by which marine mammals explore their environment and objects. Pulses of ultrasonic (the frequency
is too high to be heard by humans) sound is sent out through the blowhole. When the sound waves bounce off
objects in their path, a portion of the signal is reflected back. By measuring the time between sending out the
sound and its return, these marine mammals can find out the size, shape, direction, and distance of an object.
This system of sensing the environment is an advantage in orientation, navigation, and capturing prey in dark or
turbid waters.
emergent coast
a category of primary coast that results from the land being lifted, either by tectonic activity or rebound from the
weight of heavy glaciers, which exposes the former sea bottom bit by bit forming continuously new shoreline.
erosion
the wearing away of soil or rock.
euphotic zone
topmost layer of ocean zones and is defined by how deeply photosynthetic life can be found.
fetch
the distance the wind blows.
filter feeders
creatures that pull small bits of organic material, like plankton and larvae, from the water as it moves
past them.
fjords
u-shaped valleys formed by glacial action. Fjords are found in areas with long histories of glacier
activity, like northern Europe, Alaska and Canada.
flood
tidal currents that are moving toward the beach.
guyot
a seamount whose peaks have eroded and become a flat surface
gyres
the large rotating loops generated from currents flowing in circular motion.
herbivores
animals that eat only vegetation.
holdfasts
root-like structures of plants to help hold on to the rocky bottom.
keratin
the same protein that makes up hair and fingernails, and is strong, yet elastic
longshore current
a current found along the coast that flows parallel to the beach. This current is caused when waves
strike the beach at an angle. The front part of the wave hits the shallow water first and slows down.
The rest of the wave bends as it comes onto the shore creating a current that parallels the beach. Larger
waves, which strike the beach less often at greater angles, create stronger longshore currents. In areas
where longshore currents often occur, sandbars form.
marine terraces
a characteristic feature of emergent coasts formed as tectonic uplift moves the land upward in short
bursts, which are then worn by wave action into relatively flat surfaces, somewhat like a large
staircase.
mid-ocean ridge
two chains of mountains separated by a large depression that form at a spreading center.
mixed tides
a single low tide follows two high tides. Parts of the Pacific Basin contain mixed tides.
mutualism
beneficial relationship between organisms.
myoglobin
the oxygen-binding protein found in blood. It stores oxygen and helps prevent muscles from losing
oxygen.
neap tides
Phenomenon in which very little difference exists between high and low tides. Neap tides happen
when the alignment of the Earth, Moon, and Sun form a right angle. Opposite of spring tides.
necrotic zone
the first 200 meters (656 feet) of ocean water, which includes the seashore and most of the continental
shelf.
northeast and southeast trade winds
the winds at the equator that blow in one direction all year.
oceanic zone
extends from 200 meters (656 feet) deep all the way down to the bottom of the ocean, which can be
thousands of meters deep.
olfactory
sense of smell
osmosis
the process where water flows from a low salinity environment through a membrane to a higher
salinity environment to try and equal out the salt content on both sides of the membrane.
pelagic environment
the ocean waters
phytoplankton
one of the tiny drifing ocean organisms that uses light energy to convert carbon dioxide and water into
food.
pinnipedia
a latin word meaning "feather-footed" and refers to the flippers of pinnipeds, which are shaped like
wings or feathers.
plunging breakers
waves that occur on beaches where the slope is moderately steep. This kind of wave normally curls
over forming a tunnel until the wave breaks.
polar easterlies
the winds at the highest latitudes that blow in one direction all year.
polyps
members of individual coral colonies. Polyps consist of a tube and an oral disc, or mouth, surrounded
by tentacles, which the polyps use to capture food.
primary coasts
coasts created by non-marine processes because of changes in the land, such as river deltas or lava
flows.
rift valley
a large depression.
rip currents
can happen when longshore currents, which move parallel to the beach, bounce seaward because of a
change in the bottom’s structure. Also known as rip tides.
river delta
a type of primary coast formed where a river deposits soil and other material as it enters the sea.
river-dominated delta
a type of delta formed when there are large amounts of material in the water, and tidal action is
relatively low.
seamount
began life as volcanoes formed over hot spots in the ocean floor. After the crust moves off the hot spot,
the volcanic activity stops.
secondary coasts
coast formed by marine action because of changes in the ocean, such as the creation of barrier islands
or coral reefs.
semi-diurnal tides
tides that occur twice a day. This means a body of water with semi-diurnal tides, like the Atlantic
Ocean, will have two high tides and two low tides in one day.
spilling breakers
waves that occur on beaches with gentle slopes. These waves break far from the shore, and the surf
gently rolls over the front of the wave.
spit
Narrow peninsula of sand along the coast formed by longshore currents carrying large amounts of
sand.
spreading center
where two plates are drifting apart.
spring tides
Phenomenon in which a very large difference between high and low tides exists. For a spring tide to
occur, the Earth, Moon, and Sun must be in a straight line.
submergent coast
A category of primary coast that results from a general sea-level rise and crustal subsidence. Most of
the eastern United States has submergent coastlines. One example is the Chesapeake Bay.
submersible
a great scientific tool to help researchers explore the ocean depths. They are small submarines that can
maneuver underwater easier than larger submarines. Submersibles are equipped with viewports
(windows), searchlights, mechanical arms, cameras and scientific instruments that enable seeing and
recording data from underwater vehicles.
surging breakers
waves that occur on beaches where the slope is very steep. The wave does not actually break. Instead, it rolls
onto the steep beach. These kinds of breakers are known for their destructive nature.
tectonic activity
changes in the structure of the rock and soil because of earthquakes.
tidal current
horizontal current associated with tides that can be described as either ebb or flood.
tidal range
measurement of the difference between the high and low tides. Tidal ranges can be measured in inches,
like those in Lake Superior, Michigan, or tidal ranges can be measured in feet, like those in the Bay of
Fundy in Alaska.
tide-dominated delta
a type of delta found where the daily tidal range is more than a meter; it has many branching channels
and long narrow islands formed as the tide and river flow in different directions.
tombolos
narrow sand deposits connecting a near-shore island with the beach.
trough
valley between two waves; the lowest point on a wave.
tsunami
The most dramatic and destructive of waves caused by underwater disturbances, such as volcanoes,
earthquakes, and landslides. These waves can reach heights of 120 feet (40 m) or more. The larger the
disturbance, the larger the tsunami will be.
turbidity currents
are bottom currents that carry lots of sediment
undulating
a way marine mammals swim by moving their hindquarters from side to side
wave height
a vertical distance between a wave’s crest and the next trough.
wave period
measures the size of the wave in time. A wave period can be measured by picking a stationary point
and counting the seconds it takes for two consecutive crests or troughs to pass it.
wave-dominated delta
little more than a bulge on the shoreline since there is so much wave activity that all the sediment is
spread evenly along the coast and does not accumulate at the river’s end.
wavelength
the horizontal distance either between the crests or troughs of two consecutive waves.
westerlies
the winds at the mid-latitudes that blow in one direction all year.
zooplankton
is the floating creatures ranging from microscopic diatoms to small fish and shrimp.
zooxanthellae
a single-celled algae living within each coral polyp to provide food to the polyps by photosynthesis.