Page 490 - (DK) Ocean - The Definitive Visual Guide

488 GLOSSARY

Glossary

A separately. They often live in extreme barbel Sensitive fleshy projections greenish; usually a response to an
environments, such as deep-sea vents.
increase in the availability of nutrients
often found in pairs around the
See also bacteria. mouths of some fish. in the water. See also phytoplankton.
abyssal Relating to oceanic depths
greater than about 6,500 ft (2,000 m). Arctic Circle Line of latitude in the barnacles Specialized crustaceans blue-green algae see cyanobacteria.
The abyssal plain is the flattish plain Northern Hemisphere north of whose adults live attached to rocks bony fishes The large group that
at 13,000 –20,000 ft (4,000–6,000 m) which there is at least one day of and other surfaces. They are protected includes all fish species except jawless
that forms the bed of most ocean 24-hour sunshine and at least one by hard shell-like plates and filter- fishes, sharks, and other cartilaginous
basins. The abyssal zone is the region day of 24-hour darkness per year. feed using highly modified limbs. fishes. See also cartilaginous fishes.
of both seabed and open water arthropods A major group (phylum) See also crustaceans, filter feeding. bore see tidal bore.
between 6,500 ft (2,000 m) and the of invertebrate animals with jointed barrage Human construction built
brackish Saltier than fresh water, but
abyssal plain. See also bathyal, hadal. legs and a hard outer skeleton. It across an estuary or inlet to protect less salty than typical ocean water.
air mass A body of air with relatively includes crustaceans (crabs, shrimp, against flooding by heavy seas. breaker zone The zone of a beach, or
uniform temperature and pressure, and relatives), insects, spiders. See barrier island A permanently exposed other shoreline, where waves break.
forming above a given region of also crustaceans, exoskeleton. bar of sand or pebbles lying parallel
Earth’s surface. Its characteristics asexual reproduction Reproduction to a coastline. A barrier beach is a breakwater An artificial barrier built
derive from this surface region and that does not involve combining similar structure, but can be attached in the sea, usually near a harbor, to
are distinct from surrounding air the genes from two individuals to the mainland at one or both ends. protect against waves and heavy seas.
masses. “Tropical maritime” and (sex). It can consist of splitting brittlestars Echinoderms with narrow,
barrier reef A coral reef parallel to, but
“polar continental” are examples. or fragmenting the body, the budding jointed, flexible arms; related to
some distance from, a shoreline. starfish. See also see echinoderms, starfish
albedo The extent to which incoming of new individuals, or specialized basalt A common volcanic rock;
radiation is reflected from a surface. structures forming, such as spores. originally solidified lava. The rock of bryozoans Filter-feeding colonial
Ice has a high albedo, reflecting most atoll A low, ring-shaped island, the ocean floor is mainly basalt that animals that live attached to surfaces,
of the Sun’s radiation reaching it. or series of arc-shaped islands, has spread from mid-ocean ridges. such as seaweed fronds, either as flat
algae Simple plants and plantlike forming the rim of a shallow lagoon. basin see ocean basin. sheets or as tufty, plantlike growths.
protists that can photosynthesize, The structure results from an bathyal Relating to ocean depths Sometimes called “moss animals.”
ranging from seaweeds (macroalgae) accumulation of coral on top of between about 660 and 6,500 ft (200 bycatch In fishing, the portion of a
to microscopic plankton (microalgae). a sunken volcano. See also lagoon. and 2,000 m). The bathyal zone is the catch made up of non-target species.
Some types of algae, such as green authigenic Of sediments: formed region of seabed and water column
microalgae and green seaweeds, are locally in the ocean (especially via between these depths. See also abyssal. C
often classified as plants. Red and chemical processes), not transported
brown seaweeds are also algae, but from elsewhere. See also sediment. beach face The steeply sloping part of
a beach, below a berm. See also berm. calcareous Consisting of or containing
are often classified separately. autotroph An organism, such as a
Singular alga. See also cyanobacteria, plant, that can make its own food, benthos Living organisms that live on calcium carbonate.
photosynthesis, protists, seaweed. rather than eating or absorbing food or in the seabed (benthic organisms). calcium carbonate The chemical
amphipods A group of small, produced by other organisms. berm A ridge of sediment high on CaCO . It is the main constituent
3
of coral skeletons and mollusk
common, shrimplike crustaceans, See also photosynthesis, primary producer. a beach, left behind by a high tide. shells, limestone, and chalk.
flattened from side to side, which Also called a beach ridge.
calve To shed icebergs into the sea.
live mainly on the sea floor and biodiversity The diversity or variety
feed on detritus (dead material). B of living organisms; determined by, See also icebergs.
anadromous Of fish: living most of backshore Part of the shore above the for instance, the number of species, carapace The upper shell of a turtle;
their lives at sea but entering rivers average high-water mark, affected by or the variation within species. the protective outer covering
to breed, for example, the salmon. biogenic Formed by the action of of some other animals, such as crabs.
the sea only during the highest tides
See also catadromous. living organisms. carbon cycle The cycling of carbon
and storms. See also foreshore. through the environment. During
anaerobic Relating to processes bioluminescence The production of
backwash The flow of water back the cycle, carbon exists in the bodies
occurring without oxygen, or to light by living organisms.
to the sea after a wave has broken of living things, in carbon dioxide in
organisms that are able to live in the on a beach. biomass The total mass or weight
absence of oxygen. See also anoxic. of living organisms in a given area. the atmosphere and oceans, in fossil
bacteria Microscopic single-celled fuels, and in rocks such as limestone.
anemones Solitary cnidarians that live organisms abundant in all ecosystems. biome Any large-scale association
attached to surfaces and grab passing Their cells are much smaller than of plants and animals, especially one cartilaginous fishes Fish, such as
prey with their stinging tentacles. See sharks, rays, skates, and chimaeras,
those of animals and plants and dependent on particular climatic whose skeleton is of cartilage, not
also cnidarians, coral, polyp.
have no nucleus. See also archaea, conditions. Mangrove swamp and bone. See also bony fishes.
annelids see segmented worms. cyanobacteria, protists. the abyssal plain are marine biomes. catadromous Of fish: living most of
anoxic Of a habitat: without available baleen Horny plates in the mouths bioturbation Disturbance and mixing their lives in fresh water but migrating
oxygen for living creatures. of some whales that are used to strain of seafloor sediments, usually by to the sea to breed. Eels are an
Antarctic Circle Line of latitude in food, such as krill, from the water. burrowing animals. example. See also anadromous.
the Southern Hemisphere south bank A shallow region of sea bivalves Mollusks, such as clams, cephalopods A group of swimming
of which there is at least one day of surrounded by deeper water. Often mussels, and oysters, that have a shell mollusks that includes squid, cuttlefish,
24-hour sunshine and at least one the site of productive fisheries. made up of two hinged halves. Most octopuses, and nautiluses. They have
day of 24-hour darkness per year. bivalves move slowly or not at all, large brains and demonstrate complex
bar A long, narrow, offshore deposit of
anticyclone A pattern of circulating air sediment lying parallel to a coastline. and are filter feeders. See also filter behavior. See also mollusks.
in the atmosphere with high pressure Bars may be permanently submerged, feeding, mollusks. chemosynthesis A process in which
in the center; usually associated with or exposed at low tide. A bar that is black smoker A hydrothermal vent some organisms make their own food
settled weather. See also cyclone. always exposed is a barrier island. A in which the emerging hot water is using the energy from naturally
archaea A group of tiny, single-celled bar across the mouth of a bay and colored black with dark minerals. occurring chemicals such as hydrogen
organisms. Like bacteria, they have attached to the coast is a baymouth bloom A rapid growth of plankton, sulfide. See also photosynthesis,
no cell nucleus, but are classified bar. See also barrier island, spit. often turning the water cloudy and autotroph, primary producer.