Page 494 - (DK) Ocean - The Definitive Visual Guide

492 GLOSSARY

and filter-feed. See also segmented short-wave forms, these are radio sea cave A cave created at the foot habitually staying in one position.
worm, tube worm. waves, microwaves, infrared (heat) of a cliff by wave action. See also sessile.
polynya An area of open water in an rays, visible light, ultraviolet light, sea cucumbers see holothurians. sediment An accumulation of solid
otherwise ice-covered sea, especially X-rays, and gamma rays. Short- sea fans Fan-shaped corals belonging particles that have settled out from
in the Arctic. wavelength electromagnetic to the gorgonian or horny coral water; also used for deposits left by
radiation has the highest energy.
polyp One of the two main body- group. Though often growing on other agencies such as the wind.
forms of cnidarians. An anemone radiolarians Single-celled predatory coral reefs, they are not reef formers sedimentary rock Any rock
or coral animal is a polyp. Polyps organisms mainly living as plankton, themselves. See also coral. originating from sediment that
are typically tubular and attached often with a delicate, perforated, sea pens A group of soft-bodied, has later become compacted and
to a surface at their base. See also spherical skeleton. Radiolarian colonial cnidarians. Each colony hardened, such as sandstone.
cnidarians, medusa. remains of are an important part resembles a single individual, segmented worms A major group
of some oceanic sediments.
prevailing wind A wind that tends to with one large, burrowing polyp (phylum) of worms, also called
blow from a particular direction. See reclamation The artificial conversion anchoring the colony in seafloor annelids, whose body is built from
trade winds, westerlies. of a former coastal sea or wetland mud, and smaller polyps feeding and repeating units (segments) each
area into dry land.
primary coast A coast whose features reproducing. See also cnidarians, polyps. bearing copies of organs, such as
have not been significantly altered reef see coral reef. sea slugs Shell-less marine gastropods, kidneys. The phylum includes
by marine erosion, the activity of refraction The change of direction of often with bright colors and tufty earthworms, plus many marine
animals such as corals, or human a wave when it passes into a different gills (ctenidia) on their backs. Sea species, mostly within a subgroup
intervention. See also secondary coast. medium—for example, light waves slugs are carnivores and are not called the polychaetes. See also
primary producer Often called simply passing from air into water. Ocean closely related to land slugs. Also phylum, polychaetes, worm.
a producer, an organism that makes waves are also refracted when they called nudibranchs. See also gastropods. sessile Of an animal: attached
food, using energy either from the reach shallow water. sea stack An isolated pillar of rock left permanently to a surface, especially
Sun or from naturally occurring respiration (1) Breathing. (2) Also standing offshore on a rocky coastline without a stalk, and not able to
inorganic chemicals. See also called cellular respiration, the after all the surrounding land has move around. See also sedentary.
autotroph, chemosynthesis, photosynthesis. biochemical processes within cells been eroded away. sexual dimorphism Situation in
productivity Rate at which living that break down food molecules, sea urchins A group of echinoderms, which the males and females of
material is produced by organisms usually by combining them with usually with a rigid case called a test, a species differ in appearance, for
by growth and reproduction. See oxygen, to provide energy for an a globular body, long spines, and a example, in color, shape, or size.
also primary producer. organism. See also anaerobic. downward-facing mouth. Most graze shrimp Any of various small, usually
prokaryotes Organisms such as revetment A sloping structure of algae from hard surfaces, though the swimming crustaceans. True shrimps
bacteria and archaea, whose cells spaced wooden or concrete beams, heart urchins and sand dollars are are relatives of crabs and lobsters.
are smaller and simpler in structure constructed to protect a beach or burrowers. See also echinoderms. siphon In mollusks: a fleshy tubular
than the cells of animals, plants, and low cliff against erosion. seafloor spreading The creation of extension of the body that aids the
protists. Cells of prokaryotes have ria A winding inlet of the sea, a new oceanic crust by the upwelling flow of oxygenated seawater to the
no nucleus. See also archaea, bacteria. drowned former river valley. Most of magma at mid-ocean ridges and gills or sometimes transports food
protein A large molecule built by present-day rias were created when consequent spreading of the sea floor particles for filtering. Cephalopods
organisms from smaller molecules sea levels rose at the end of the last on either side. See also plate tectonics. use their siphons for jet propulsion.
called amino acids. Proteins range ice age. Unlike a fjord, a ria was seagrasses Any of various plants able See also cephalopods.
from the enzymes that promote never occupied by a glacier. to grow and root in shallow, sandy siphonophores Floating, predatory,
chemical reactions in body cells, to ribbon worms A major group (phylum) seabed along coastlines, especially in colonial cnidarians, such as the
structural materials such as keratin— of narrow-bodied, unsegmented warmer seas. Although not actually Portuguese man-of-war. The colony
the tough protein that makes up marine worms, also called proboscis grasses, they are true flowering plants, members have specialized functions
hair, horn, and nails. worms, some of which can reach unlike seaweeds, which are algae. but act together so that the colony
protists A wide grouping of often 160 ft (50 m) in length. sea ice Ice that forms on the surface functions like a single animal. See
unrelated, microscopic organisms, rip current A current flowing away of the sea, as distinct from ice shelves also cnidarians, colonial, polyp, zooid.
traditionally classified as a single from a shoreline, carrying water and icebergs, which originate on sonar A method of echo-sounding;
kingdom. It includes mostly single- that has been pushed shoreward land. Some sea ice forms only in often used more broadly as a
celled forms, either animal-like by waves. See also tide rip. winter, while other sea ice is semi- synonym for echolocation. See
(formerly called protozoa) or plant- rip-rap Boulders piled deliberately permanent. Sea ice forms and evolves also echolocation, echo-sounding.
like (many of which are termed algae). on a shoreline to prevent erosion. in several stages. See frazil ice, grease Southern Oscillation see ENSO.
Some experts also include larger ice, pack ice, pancake ice.
algae (seaweeds). Protist cells contain seamount A submarine mountain, spit A peninsula of sand or shingle
nuclei, like the cells of animals and S usually an extinct volcano. or both created by longshore drift,
plants, but unlike those of bacteria. sea spiders A group of eight-legged usually at a point where the shoreline
pteropods Swimming, planktonic salinity Degree of saltiness. predatory marine arthropods. It is not changes direction. See also bar, barrier
island, longshore drift, tombolo.
gastropod mollusks, also called sea salps Barrel-shaped, delicate-bodied agreed whether sea spiders are closely
butterflies. The crawling foot of their tunicates that live as filter-feeders in related to land spiders or not. sponges A large group (phylum) of
snail-like ancestors has evolved into the plankton. See also tunicates. sea squirts see tunicates. marine animals with a very simple
muscular “wings” that propel them salt marsh An ecosystem developing structure that feed by creating
along. See also gastropod, plankton. on sheltered, flat, muddy coastlines, seaweed A member of any of three currents through their bodies and
pycnocline A boundary region in where tidal flats are colonized by salt- main groups of large-bodied algae. filtering small particles from the
Seaweeds can make their own food
ocean waters within which density tolerant land plants. See also tidal flat. by photosynthesis, but they lack roots. water. They have no muscles or nerve
cells, and sometimes no symmetry.
changes rapidly. It typically results sand dune see dune. Their classification is not agreed, but
from a combination of temperature scute Any of the horny plates that green seaweeds seem to be related to spore (1) A tiny structure produced
and salinity levels, both of which form the outer covering of the shells plants, while red and brown seaweeds (usually in large quantities) by non-
affect density. See also thermocline. flowering plants, fungi, and some
of turtles; also used to described a may represent two unrelated lines of
protists, from which a new individual
similar protective structure on some evolution. See also algae. can grow. Spores are much smaller than
R fish and other animals. secondary coast A coast with features seeds and usually produced asexually,
sea arch A natural arch on a rocky significantly altered by marine sometimes forming part of a complex
radiation The emission of high-energy shoreline, usually created by two sea erosion, the activity of animals such life history. (2) The inactive, resistant
particles or waves. Electromagnetic caves on either side of a headland as corals, human intervention, or all form of some bacteria that helps
radiation consists of electromagnetic eroding into each other. three. See also primary coast. them survive unfavorable conditions.
waves: listed from long-wave to sea butterflies see pteropods. sedentary Of animals such as worms: See also asexual reproduction.