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Marine Science Dictionary (BC)

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B

baleen: the filtering structure of the larger filter feeding whalesderived from hair

barrier island: small mobile island that form a breakwater for the mainland, barrier islands are usually near shore and composed primarily of sand.

basal metabolic rate: In physiology, the metabolic rate, or rate of energy usage of an organism at rest

bathy: (pelagic/benthic) bathyl -Bathypelagic and bathybenthic refer to the middle to lower regions of the ocean. The bathy (often bathyl) zone generally extends from a depth of 1000m to 4000m. An animal that is benthic and lives in the bathy zone would be bathybenthic when a pelagic animal would be bathypelagic.
see picture

bathythermograph: a tool that measures depth and temperature simultaneously.
 
Batsian Mimicry: When evolution has led a species that is palatable to predators to resemble a species that is not
 
benthic: Benthic animals are those associated with, living on or within (as in a burrow) the substrate, or bottom of a water body. This term is more often used to refer to invertebrates.

benthos: The organisms that live on the bottom, the benthic organisms of an area.

bio-diversity: The number of species within a given area.  Most simply given by number of species/square meter or some other measure of area.  In three dimensional environments (the ocean) measures of volume are sometimes used.

bioluminescence: the production of light by living organisms.  Caused by the breakdown of the protein luciferin by the enzyme luciferase.  Many planktonic organisms such as dinoflagellates and ctenophorans are bioluminescent.  Deep sea organisms frequently have symbiotic bioluminescent bacteria housed in special organs. See photophore

biological rhythm: regular period of activity and inactivity

biotic: With life, having life.  The biotic components of an environment include the other living things within that environment, contrast with abiotic

Bivalvia: (class) Sub-grouping of the Mollusca.  They are also known as the Pelecypoda. These are the clams, oysters, mussels etc. The group is characterized by a two part hinged symmetrical shell.

black smoker: see hydroterhmal vent

bongo net: two connical plankton nets pulled simultaneously

book gills: leaf like gills of some arthropods, especially under the abdomen of horseshoe crabs

body sides and regions: For the purpose of referring to animals the its body is separated into regions, based on the way it would orient itself in nature, and rarely from the way its evolutionary ancestors might have oriented themselves.  The area on the top, or back, of an organism is the dorsal region or side.  The area on the area on the bottom, opposite the dorsal is the ventral.  The area towards the rear of an organism as it moves is the posterior end or region. The end opposite the posterior, towards the front as it moves, would be the anterior end or region.

bilateral symmetry: symmetry in animals that can be divided into two roughly symmetrical sides along a single median plane

blue green algae: see cyanobacteria

broadcast spawning: when animals mate by releasing gametes in the water, usually synchronized, contrast with copulation

C

calcareous: made of or containing calcium carbonate

calcarious ooze:  marine sediment that consists of 10% calcium carbonate

calcium carbonate: compound containing one calcium atom and three oxygen atoms.  Comon in the hard secretions of many organisms, ecspecialy the shells of mollusks and the skeleton of coral polyps.

camouflage: structural or color adaptations that allow an animal to blend with its environment

carapace: the upper half of the shell of sea turtles, the portion of the exoskeleton of crustacea that covers the cephalothorax.

carbohydrate: one of four types of organic compounds.  Serves as energy storing molecules.

carrying capacity: The number of individuals or living material that a given habitat or area is able to support.  Carrying capacity is due to the limitation of some resource.

catadromous: a diadromous (see diadromous) lifestyle of fishes where the adults live in fresh water and return to a marine environment to spawn.  The North American and European freshwater eels  (genus: Anguilidae) are an example.  Contrast with anadromous.

Cephalopoda: (class) Sub-grouping of the Mollusca.  are arguably the most advanced of the invertebrates. They include the octopus, nautili, squid, and cuttlefish.

cephalothorax: the fused head and thorax of several groups of arthropods.  esp. the crustaceans

cellular respiration: the chemical reaction that releases energy from carbohydrates and forms carbon dioxide and water

cellulose: carbohydrate that forms the cell wall of true plants and some algae

Cephalaspidomorpha (class): Sub-grouping of the phylum Chordata.  These are mostly fresh water, jawless parasites on other fishes, commonly known as the lampreys. They lack jaws, paired fins, bone, and scales. Lampreys have five gill pores and as adults have well developed eyes.

chelliped: the first walking appendage of may crustacean, adapted for grasping/pinnching.

chemoautotroph: see autotroph, see archaebacteria

chitin: a tough polysaccharide  that forms the exoskeleton of arthropods and the cuticle of other animals.

chlorophyll: the most common class of photosynthetic pigments

Chlorophyta: the green algae, believed to have given rise to the terrestrial plants.

choanocyte: the feeding cell of sponges. uses a flagella to create a current that draws food into "collar" of microvilli.

Chondrichthyes: (Class) These are the cartilaginous fishes. They exhibit no true bones, although the cartilage that makes up their skeletons may be ossified (hardened) by calcium salts. This class is further devided into the subclasses Elasmobranchii (Sharks, Rays and Skates) and the Holocephali (Chimaeras).

Chordata: (Phyla) These are animals which have, at some point in there life, a notichord, pharyngial (throat) gills,  and post anal tail.  Many organisms may lose these features early in there ontogeny.  The chordata are divided into three subphyla.   The urichordata are the sea squirts or tunicates.  The cephalochordata are the  lancelates.  The vertebrata are animals with backbones.

Chromatophore/chromatocyte: an organ or cell that gives color to or allows for color change in an organism.  The color change is caused by the expansion of the pigment containing cells.

circalunar: biorhythm entrained by lunar cycles, or monthly tidal cycles

Circadian: any 24 hour or daily cycle, daly biorhythm

circannual: yearly biorhythm

circatidal: biorhythm entrained by daily tidal cycles

Cirripedia: (class) These are sessile crustaceans  which use what would be there walking appendages to filter feed. The form a series of calcareous plates around themselves and are commonly known as the barnacles.

cladistics: The study of taxonomy with special intent that groupings represent phylogenic/evolutionary relationships

clasper: the reproductive organ  of male cartilaginous fishes, a modified pelvic fin

cloaca: common posterior body opening of cartilaginous fishes, some reptiles and birds

closed circulatory system: a system where the circualtory fluids never leave the system of tubes that moce them.  Respiratory gasses, cell nutrients and wastes must leave or enter the system by diffusion through the walls of the vessels.

clutch: a group of eggs or offspring

Cnidaria: (phyla) These are gelatinous invertebrates characterized by the presence of cnidocytes (=stinging cells). Cnidarians are noted for the two types of body forms they can achieve. These are the Medusae as in a jelly fish and the polyp as in a coral polyp. A species of cnidarean does not necessarily maintain the same body form throughout its life cycle. Something we commonly think of as a medusae for example probably also has a polyp phase. Cnidareans are devided into four major classes;  Cubozoa- marine, the sea wasps.  Hydrozoa, marine and fresh water, the hydras and colonial forms such as the Portuguese man of war. Scyphozoa, mostly marine, the true jellyfish Anthozoa- marine, the "flower animals" soft and hard corals as well as anemones.

cnidocyte: the stinging cells of the cnidarias (jellyfishes, hydras and anemones) the cnidocyst and nematocyst refer to the actual stinging organelle.

coadaptation: when organisms evolve to be dependant on one another, and the adaptations involved become more specific.

coccolithophores: important marine phytoplankton with a cell wall of circular interlocking calcarious plates called coccoliths

codon: a series of three base pairs in DNA that code for a particular amino acid

Coelocentera: archaic phyla name that included the radiate two tissue layered phyla, Cnidaria and Ctenophora.

coelocenteron: oral sac, or gut, of Cnidarians.

coelom: A body cavity that is fluid filled and lined by serous membrane.  Most segmented animals are coelomates.

coelomate: having a coelom

cold blooded: archaic, layperson's phrase for both the terms ectotherm and heterotherm.

commercial extinction: When a fish is so uncommon that it is not financially

community: in ecology, all the organisms that live within a habitat or area

competition: an interaction of individuals, where they compete for some resource.  The resource might or might not be biotic.  Also, the resource might or might not be in limited.  There are two main types of competition.  In exploitative competition organisms both utilize a common resource, which is limited.  They do not, however, physically interact, the interaction is in the race to utilize the resource.  In interference competition organisms utilize a common resource, which might or might not be limited.  One organism will interfere with the others utilization of the common resource.

conductivity: the ability of a substance to conduct electricity, used to infer the mineral or salt content of a sample of water.

cones: photo sensitive nerves able to distinguish between different wave lengths of light, and thus see color

conformity: When an animal does not maintain its internal variables at a level different from that of the environment it is said to be conforming. For example: the osmotic pressure within a jellyfish's body is similar to that of its surroundings (seawater) Therefore it is an osmotic conformer. Generally the need to conform internal variables is a trait of less evolved animals. See also Regulation.

conspecific: of the same species

consumer: An organism which can not produce its own nutrition, and must consume other organisms.  This includes all the Fungi,  Animalia and many Bacteria.  Contrast with producer, and autotroph.  Synonymous with heteroroph

consummatory: a trait that is not variable within a species, stereotypical.  Contrast with appetitive

continental break: the place in the continental shelf that marks the transition from shelf to slope, where the gradual dropoff to deeper water becomes more pronounced
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continental island: islands that are part of a continental land mass

continental margin: the submerged edge of a continental landmass
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continental shelf: the somewhat flat, shallow, submerged part of a continental land mass
see picture

continental slope: the "face" of the continent, where the rise from abyssal depths occur
see picture

convergent evolution: When traits in dissimilar organisms tend to take on similar form or purpose.  An example of this would be the similar body forms of pelagic sharks and dolphin.  This form allows the animals to exploit the same environment while they evolved in very different ways. Contrast with divergent evolution.

Copepoda: (class) This is a highly diverse group. Adults are similar to larval forms of other crustaceans. Copepods fill many ecological niches.  Planktonic copepods of the genus Calanus are among the most abundant  animals on Earth.

copulation: sexual reproduction when the male delivers sperm to the body of the female, contrast with broadcast spawning

coral reef: a habitat created by the slow build up of the calcium carbonate skeletons of many coral polyps.  There are several types of coral reefs and coral reefs have distinctive zones.  The most diverse marine habitat

coral bleaching: A condition when coral polyps expel symbiotic zooxanthellae, assumably due to stress.  The loss removes the color giving a coral aggregation a white appearance

cordgrass: important estuary grasses. example Spartina

Coriolis effect: the tendency, due to the rotation of the Earth, of moving objects in the northern hemisphere to veer to the right, and things in the southern hemisphere to the left

countershading: when an animal is dark on top and light on the bottom, a type of camouflage for animals living in the water column

crepuscular: During the hours of twilight.  An animal most active during the twilight hours of dawn or dusk.  Contrast with diurnal and nocturnal

Crustacea: (subphyla) This is a large group of mostly aquatic Arthropods which includes most of the recognizable aquatic arthropods. All Crustaceans have two pairs of jointed antennae and two pairs of mouthparts.

Ctenophora: (phyla) These are the comb jellies. They are characterized by the presence of eight "ctene" or comb rows for propulsion through the water. The Ctenophorans used to be maintained in a phyla with the Cnidarians called the Coelentara. Older texts, and books without a strong emphasis on Zoology might maintain this, incorrect name. There are two Major classes of Ctenophorans; Nuda, Without tentacles Tentaculata, with two tentacles.

Cyanobacteria: the blue green algae, prokariotes (bacteria) that form a major component of the phytoplankton and frequently form mat coverings over near shore habitats.