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Glossary of Terminology: C

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Number of records found : 500


c-card - a scuba diving certification card from scuba certifying agencies, such as NAUI, BSAC, NOAA, PADI, etc.

cadaster - a public register showing the details of ownership and value of land; also spelled "cadastre"

cadastral survey - a survey which creates, marks, defines, retraces or reestablishes the boundaries and subdivisions of the public land of the United States. It is derived from the word cadastre, meaning a public record, survey, or map of the value, extent, and ownership of land as a basis of taxation

caecum - a blindly ending sac arising from the gut or some other hollow organ

calathiform - cup-shaped

calcareous - composed of or containing a substance made of calcium carbonate

calcareous ooze - a biogenous sediment that is made of the calcium carbonate shells and skeletons of marine organisms

calcification - the process by which corals and calcareous algae extract calcium from seawater and produce it as calcium carbonate

calcite - a mineral made up of a crystalline form of calcium carbonate

calcite skeleton - a skeleton composed of the calcite form of calcium carbonate

Image of a queen conch

This Queen Conch (Strombus gigas) utilizes calcium carbonate in forming its protective shell. (Photo: Andy Bruckner)


calcium carbonate (CaCO3) - a molecule consisting of calcium, carbon and oxygen secreted by corals to their skeleton. It is also secreted by mollusks to form their protective shells

calibrate - to check or adjust the graduations of a quantitative measuring instrument

calice - the upper surface of the corallite; a cup-shaped depression on the corallite surface

calicle - one of the small cuplike cavities, often with elevated borders, covering the surface of most corals. Each is formed by a coral polyp; the calyx

calicoblast - the primary cell of the calicoblastic epithelium (calicodermis). The calicoblast secretes the organic matrix leading to the calcification and formation of the calcareous skeleton of scleractinian (hard or stony)corals

calicoblastic epithelium - a thin squamous epithelial layer of cells in stony (hard) corals which deposits the white calcium carbonate skeleton

caliculate - cup-shaped

calorie - a unit of measurement defined as 4.184 absolute joules or the amount of energy it takes to raise the temperature of one gram of water from 15 to 16 degrees Celsius (or 1/100th the amount of energy needed to raise the temperature of one gram of water at one atmosphere pressure from 0 degrees C to 100 degrees C). Food calories are actually equal to 1,000 calories (1 food calorie = 1 kilocalorie)

calyx - the upper or open end of the corallite or coral polyp cup; the central body of entoprocts (goblet worms) or crinoids (sea lilies and feather stars)

campaniform - bell-shaped

cancellous - possessing a spongy or porous surface

cancellous - reticular, spongy, or lattice-like structure; usually pertains to bone

cancriform - crab-shaped

Image of a moray eel

Moray eels are armed with sharp canine teeth used for capturing prey and also for defense. (Photo: Dr. Tom Doeppner, Brown University)


canine tooth - a pointed, conical tooth that is located at the front or edge of the jaw. Canine teeth are used for piercing and grabbing prey

cannibalism - predation of an animal by a member of its own species

canopy - the more or less continuous cover of branches and foliage formed collectively by the tops, or crowns, of adjacent trees

cape - a piece of land that that projects out into a large body of water

capsid - the protein coat of a virus particle

captaculum - a filamentous tactile organ with an adhesive, sucker-like end near mouth of a tusk shell (mollusks in the class Scaphopoda).The captacula are used to gather small particles of food in the sand and pass them to the mouth

captive breeding - raising animals (or plants) in controlled conditions to produce stock for subsequent release into the wild

Image of a spiny lobster

The carapace is the hard shell covering of the cephalothorax of this spiny lobster.


carapace - a hard shield, or shell covering, found over all or part of the anterior dorsal portion of an animal. In lobsters, shrimps, crayfish, and crabs, the carapace is the part of the exoskeleton that covers the head and thorax and protects the dorsal and lateral surfaces. In many crustaceans, the term carapace is also used to describe the hard, protective covering of the cephalothorax, as that of the horseshoe crab. The carapace of a turtle's shell is composed of expanded ribs and vertebrae overlain by dermal plates and horny scales

carbohydrase - an enzyme that acts upon a carbohydrate

carbohydrates - organic compounds composed of carbon, oxygen, and hydrogen; includes the simple sugars, double sugars, and complex sugars (starches)

carbon capture and storage (CCS) - a process consisting of the separation of atmospheric CO2 from industrial and energy-related sources, transport to a storage location, and longterm isolation from the atmosphere

carbon cycle - the cycling of carbon in the form of carbon dioxide, carbonates, organic compounds, etc., between various reservoirs, e.g., the atmosphere, the oceans, land and marine biota and, on geological time scales, sediments and rocks

carbon fixation - the conversion of inorganic carbon into organic carbon, usually by photosynthesis

carbon sequestration - the capture and long-term storage of atmospheric carbon dioxide in forests, soils, lakes, and oceans; the net process of storing carbon in a carbon sink. Sinks can include terrestrial (soil, trees), marine, atmospheric, and geological systems

carbonate compensation depth - the depth in the ocean below which material composed of calcium carbonate (CaCO3) is dissolved and does not accumulate on the sea floor

carbonate mound - a seabed feature usually constructed from carbonate-producing organisms and current-controlled sedimentation. Carbonate mounds are a unique combination of cold-water coral framework and rubble, sediment deposition, and local hydrodynamic influences

carboxyl group - the -COOH functional group, acidic in nature, found in all amino acids; the acid group of organic molecules

carcinogen - a chemical substance that causes cancer

carcinology - the study of crabs and other crustaceans

cardinal - deep scarlet red color

cardinalfish - any species of bony fishes in the family Apogonidae. Cardinal fishes are often brightly colored with attractive patterns, usually in shades of red or brown. Most are small tropical marine species, although some live in brackish and even fresh water waters

Caribbean ciliate infection (CCI) - a coral disease distributed throughout the wider Caribbean, caused by a ciliate protozoan in the genus Halofolliculina. The disease is characterized by a dark, mostly spotted, scattered or dense band formed of ciliates. The disease slowly kills tissues and colonies over time

Caribbean Coastal Marine Productivity (CARICOMP) - a regional coral reef, seagrass and mangrove monitoring program and network involving a number of Caribbean laboratories, parks and reserves to study land-sea interaction processes in the wider Caribbean region. Twenty-seven institutions in 17 countries participate in CARICOMP

Caribbean Coral Reef Institute (CCRI) - NOAA's Caribbean Coral Reef Institute (CCRI), inaugurated in May, 2005, is located at the the University of Puerto Rico-Mayaguez. The CCRI focuses exclusively on the acute problems of Caribbean coral reefs. Its main objective is to aid in the management and conservation of Puerto Rico’s coral reefs by providing timely, relevant information to the Puerto Rico Department of Natural and Environmental Resources and the scientific community at large. CCRI projects include conducting habitat mapping of the western shelf of Puerto Rico, assessing the status of reef resources, and assessing fishery impacts

Caribbean Marine Protected Area Management (CaMPAM) - a network of managers of marine and coastal protected areas in the wider Caribbean organized to achieve goals of conservation and sustainable use of Caribbean coastal and marine environmental resources. General activities conducted through CaMPAM's membership include sharing experiences and addressing management challenges by facilitating training opportunities, information exchange, communication, and problem solving

caridean shrimp - caridean shrimps can be distinguished from other shrimp-like creatures by the way in which the plate of the second abdominal segment overlaps the segments both in front and behind, forming a saddle. They are found in marine, brackish and freshwater habitats from the tropics to the polar regions. Carideans are taxonomically and ecologically diverse, with many remarkable adaptations for survival and reproduction.These crustaceans are placed in the infraorder Caridea, order Decapoda, and class Malacostraca

carinate - shaped liked a keel or ridge

Image of barracuda siezing prey

A carnivore (barracuda) caught in the act.


carnivore - an organism that feeds upon animals

carotene - a red, orange, or yellow pigment belonging to the group of carotenoids; a precursor of vitamin A

carotenoid - any of a group of red, orange, and yellow accessory pigments of plants or algae

carpogonium - the female gamete-producing reproductive organ in red algae, consisting of a single cell and its extension, the trichogyne

carposporangium - a single-celled structure in red algae that produces diploid carpospores on the carposporophyte

carpospore - a non-motile diploid spore formed on the carposporophyte stage of the red algae life cycle which germinates to form the tetrasporophyte stage

carposporophyte - the diploid stage of red algae which develops after fertilization of the carpogonium

CARRUS Alliance (Comparative Analysis of Reef Resilience Under Stress Alliance) - the CARRUS Alliance was organized at the 2004 International Coral Reef Symposium held in Okinawa. Its objective is to provide a basis for better understanding of coral reefs at the scale of the whole reef system. The Alliance consists of researchers conducting independently-supported long-term, interdisciplinary research on whole reef systems, including associated social and economic systems, united through agreements for the exchange of information, methods, expertise, and software. One focus of the Alliance will be on developing common research objectives, including the development of decision support systems to facilitate reef management. The Alliance will be linked to a variety of international efforts

carrying capacity - the maximum population size that can be regularly sustained by an environment; the point where the population size levels off in the logistic growth model

Image of hyaline cartilage

A microscopic section of hyaline cartilage. The cartilage cells (chondrocytes) exist in little cavities (lacunae) in the smooth, glassy cartilaginous matrix. (Photo: NIH/National Cancer Institute)


cartilage - a type of connective tissue where the functional component is the rubbery intercellular matrix that is secreted by cartilage-producing cells called chondrocytes. Cartilage exists in several forms, from glassy to fibrous in appearance

cartilagenous - pertaining to or composed of cartilage; of the consistence of cartilage or gristle

cartography - the science, technology, and art of making maps and charts. Cartography includes all the steps necessary to produce a map: planning, aerial photography, drafting, editing, color separation, and multicolored printing

caruncle - a fleshy outgrowth

catabolic pathway - a metabolic processes that releases energy as complex molecules are broken down into simpler ones

catabolism - a destructive metabolic process by which organisms convert substances into excreted compounds

Image of an American eel

The American eel is a catadromous species that spawns in the ocean, near the Sargasso Sea, but grows to maturity in freshwater streams.


catadromous species - a species that spawns in the ocean but lives parts of its life in fresh water, e.g., American eel

catalysis - the acceleration of a chemical reaction by a catalyst.

catalyst - a substance that accelerates a chemical reaction, but is not consumed or changed in the process

catchment area - the area drained by a river or body of water; also called "drainage basin"

catenation - linking of multiple copies of a macromolecule to each other

cation - a particle that carries a positive electrical charge. The cation gets this positive charge from losing negatively charged electrons

Image of a shark

Caudal fin of a shark. The dorsal lobe of the caudal fin is elongated. (Photo: Copyright Corel Corporation)


caudal - pertaining to the tail; denoting a position more toward the tail of an animal, e.g., the tail fin of a fish is called the caudal fin. Caudal vertebrae are the vertebrae which extend into the tail of an animal

Image of unicorn fish

The caudal peduncle of the spotted unicorn fish (Naso brevirostris) is located between the anal and caudal fins. (Photo: Copyright Richard C. Wass)


caudal peduncle - the narrowest portion of a fish's body, located just posterior to the anal fin and just anterior to the caudal fin

cay - a small, low coastal island or emergent reef of sand or coral; flat mound of sand and admixed coral fragments built upon a reef flat or just above high tide level. A synonym of key, as in the Florida Keys

CD-ROM (Compact Disk-Read Only Memory) - an optical medium. A CD-ROM 5.25-inch disk can hold about 650 megabytes of information

cDNA library - a collection of cDNA clones that were generated in vitro from the mRNA sequences isolated from an organism, or a specific tissue or cell type, or population; a library of cDNA sequences

Image of toxic dinoflagellate <i>Gambierdiscus toxicus</i>

This example of a single-celled organism, the dinoflagellate Gambierdiscus toxicus, produces toxins including ciguatoxin and maitotoxin. The toxins are associated with ciguatera fish poisoning.


cell - the smallest unit of living matter. All organisms are composed of cells and cell products (Cell Theory). Organisms exist either as single cells (unicellular) or as multicellular units

cell adhesion - adherence of cells to surfaces or to other cells

cell body - the enlarged portion of a neuron which contains most of the organelles      

cell culture - the in vitro growth of cells derived from multicellular organisms. The cells are usually of one type

cell cycle - the period between the formation of a cell by the division of its parent cell and the formation of two new cells by cell division

Images of 6 phases of cell division

Cell division by mitosis. A-B: Prophase - the replicated (daughter) chromosomes (chromatids) undergo extensive condensation. They are greatly thickened and shortened but are still contained within the nuclear membrane. Prophase ends with the sudden beakdown of the nuclear membrane. C: Metaphase - the replicated chromosomes converge toward the center of the cell. D: Anaphase - sister chromatids split at their centromeres. These daughter chromosomes then begin to separate from each other, and move toward one of the two spindle polar regions. E-F: Telophase/Cytokinesis - Chromatids arrive at opposite poles of cell, and new membranes form around the daughter nuclei. The chromosomes disperse and are no longer visible. Cytokinesis or the partitioning of the cell may also begin during this stage. In animal cells, cytokinesis results when a fiber ring composed of a protein (actin) around the center of the cell contracts and pinches the cell into two daughter cells, each with one identical nucleus. Chromosomal replicaton occurs during the interphase beween mitotic activities. (Photo: Dept. of Biology, University of New Mexico)


cell division - the separation of one cell into two daughter cells, involving both nuclear division (karyokinesis) and subsequent cytoplasmic division (cytokinesis). Genetically, the daughter cells are identical to the mother cell (mitosis); however, in gametogenesis (meiosis), the resultant daughter cells (gametes) have the chromosome number reduced by one-half

cell line - cells that have been extracted from human or animal tissue and now grow and replicate continuously outside the living organism

cell membrane - the structure enveloping a cell, enclosing the cytoplasm and forming a selective permeability barrier which permits the passage of solvents and solutes into and out of cells. It consists of lipids, proteins and some carbohydrates

cell wall - an extracellular material that forms the outer surface of plant, fungus, and certain bacterial cells. It is external to the cell membrane and serves in a structural and supporting role. The cell wall is composed primarily of cellulose and lignin in plants, chitin in Fungi, and peptidoglycans in bacteria

cellular differentiation - genetically-induced divergence in the structure and function of cells as they become specialized during a multicellular organism's development

cellulolytic enzyme - an enzyme that acts upon cellulose

cellulose - a polysaccharide that is composed of unbranched chains of glucose. It is the major structural carbohydrate of plants

cement - the chemically precipitated calcium carbonate present in spaces within skeletons or between grains of internal sediment

Cenozoic - the current geologic era, which began 66.4 million years ago and continues to the present

Census of Marine Life (CoML) - a global network of researchers in more than 80 nations engaged in a 10-year scientific initiative to assess and explain the diversity, distribution, and abundance of life in the oceans

Census of Marine Life (CoML)/Census of Coral Reefs (CReefs) Project - a research initiative to conduct a taxonomically diversified census of coral reef ecosystems throughout the globe. This international partnership, led by NOAA’s Pacific Islands Fisheries Science Center, the Australian Institute of Marine Science, Scripps Institution of Oceanography, and the Hawai´i Institute of Marine Biology, will expand tropical taxonomic knowledge (with a particular focus on understudied species), increase the exchange of coral reef ecosystem data dispersed throughout the globe, and develop new and innovative technology and sampling strategies, as well as contribute to the CoML barcode initiative. CReefs plans to work closely with the NOAA Coral Reef Conservation Program (CRCP) and other organizations on outreach and education, collaboration with other existing coral reef efforts, and collection and unification of data into the Ocean Biogeographic Information Center for research, management, and preservation purposes

center line - the imaginary line running from bow (front) to stern (rear) along the middle of a vessel

Centigrade Temperature Scale - a thermometric scale in which 0 degrees C (Celsius) marks the freezing point of water and 100 degrees C indicates the boiling point of water at sea level

centiMorgan - the unit of genetic map distance between two loci that show one (1) percent recombination

Central Dogma (of molecular biology) - the principal statement of the molecular basis of gene action. Genetic information is stored in and transmitted as DNA. Genes are expressed by being copied as RNA ( transcription), which is processed into mRNA (messenger RNA) via splicing and polyadenylation. The information in mRNA is translated into a protein sequence using a genetic code to interpret three-base codons as instructions to add one of twenty amino acids, or to stop translation; or more simply put, DNA carries the genetic information which is transcribed to RNA and subsequently translated to protein. Francis Crick, the co-discoverer of the double helix structure of DNA, coined the term "Central Dogma" in 1958 to characterize the all-important cellular processes whereby DNA is "transcribed" into RNA and RNA is "translated" into protein

Image of a centrifuge

A centrifuge used to "spin down" materials.


centrifugation - the spinning of a mixture at very high speeds to separate substances of different densities

centriole - one of two small cylindrical cell organelles composed of nine triplet microtubules. They form the asters during cell division

centrolecithal - a type of egg cell that has its yolk in the very center of the cytoplasm, such that the initial meroblastic cleavage of the zygote happens all around the embryo. Most arthropods have centrolecithal eggs

centromere - the center part of a chromosome that appears ‘pinched’, in between the short arm (p) and the long arm (q). The centromere holds the two chromatids together, and during cell division (mitosis) it is the site of attachment for the spindle fibers

centrosome - a granular region of a cell which contains two centrioles and is a center of microtubule organization during the division of the nucleus

cephalic - pertaining to the head

cephalization - the localization of neural coordinating centers and sensory organs at the anterior end of the body

Image of squid with egg mass

Squid (class Cephalopoda) with egg mass.


Cephalopoda - a class of the phylum Mollusca that includes squids, octopods, cuttlefishes and nautili. Many species are inhabitants of coral reefs

cephalothorax - the region of the body in decapod crustaceans that is covered by the carapace, with the boundary between the fused head and thorax indicated by the cervical groove. In lobsters, the cephalothorax is called the "body"; in shrimps, it is called the "head"

Image of sea slug

Cerata (plural of ceras) of Aeolidiella foulisi showing the brown duct of the digestive gland and the whitish cnidosac at the tip.


ceras - one of many multifunctional horn or lobe-shaped or leaf-like process on the back or side of a nudibranch mollusk (sea slug). It has a major function as a respiratory organ (a gill), and with a branch of the digestive gland, it also serves as an organ for the exchange of gases and other molecules with the blood. The ceras also stores stinging nematocysts in a structure called the cnidosac, from the cnidarians upon which they feed, which gives it a defensive function. Its ability to change color also gives it a protective camouflage function

cerulean - dark blue color

Image of a killer whale

The killer whale is actually a dolphin in the cetacean family, Delphinidae


cetacean - a marine mammal of the Order Cetacea. The Cetacea includes whales, dolphins and porpoises

chaeta - a stiff hair or bristle, made of chitin, characteristic of annelid worms. In the earthworm they occur in small groups projecting from the skin in each segment and function in locomotion. The chaetae of marine polychaete worms are borne in larger groups on paddle-like appendages called parapodia

Image of butterfly fishes (Chaetodontidae)

A pair of butterfly fishes (Chaetodontidae). Their presence and behavior serve as biological indicators of reef health.


Chaetodontidae - a family of fishes (butterfly fish) whose number and behavior may serve as indicators of reef health

chain transect - a linear transect where a chain is used to mark the line under study. By following the surface contour of the reef, chain transects provide data that may be used to calculate the estimated spatial index (the ratio of reef surface contour to linear distance of the reef)

channel - a deep and relatively narrow body of water (as in a river, harbor, or a strait linking two larger bodies) that allows the best passage for vessels; an open conduit either naturally or artificially created which periodically or continuously contains moving water, or which forms a connecting link between two bodies of water. River, creek, run, branch, and tributary are some of the terms used to describe natural channels. Canal and floodway are some of the terms used to describe artificial channels.

character - in taxonomy, any attribute of organisms used for recognizing, differentiating or classifying taxa

character displacement - the process by which two closely related species, with overlapping ecological requirements, interact so as to cause one or both of them to diverge evolutionarily in one or more traits. They differ more when they co-occur than when they do not

Charles Law - under conditions of constant pressure and quantity, there is a direct relationship between the volume and absolute temperature for an ideal gas

chart datum - the level of water from which charted depths displayed on a nautical chart are measured. A chart datum is generally a tidal datum (a datum derived from some phase of the tide)

Image of a lobster

The large pinching claw of this crustacean is the chela. The entire leg bearing the chela is termed the cheliped. (Photo: NOAA)


chela - a pinching claw of a decapod crustacean, composed of a moveable finger, the dactylus, and a fixed finger, a distal extension of the propodus

Image of a horseshoe crab

The horseshoe crab is an arthropod in the order Cheliceramorpha


Cheliceramorpha - an order of arthropods that includes horseshoe crabs, daddy-longlegs, and extinct "sea-scorpions, spiders and scorpions, mites and ticks, " Most of its marine representatives are extinct, but were prominent in the Paleozoic

cheliform - pincer-shaped

Image of a lobster

A cheliped of this American lobster (Homarus americanus) is a leg bearing a pinching claw.


cheliped - one or more pairs of thoracic legs of decapod crustaceans that terminate in a chela, or claw. The entire cheliped is often referred to as a claw

chelonitoxism - a type of food poisoning caused by eating the flesh of sea turtles.

chemical bond - the link between two atoms within a molecule. Different types of chemical bonds include hydrogen bonds, covalent bonds, and ionic bonds

chemical evolution - the chemical changes that transformed simple atoms and molecules into the more complex chemicals needed for the origin of life

Chemical Oxygen Demand (COD) - a measure of the chemically oxidizable material in water which provides an approximation of the amount of organic and reducing material present. The determined value may correlate with biochemical oxygen demand (BOD) or with carbonaceous organic pollution from sewage or industrial wastes

chemical species - in general, atoms, molecules, molecular fragments, ions, etc., being subjected to a chemical process or to a measurement. Specifically a chemical species may be defined as an ensemble of chemically identical molecular entities or the specific form of an element defined as to isotopic composition, electronic or oxidation state, and (or) complex or molecular structure

Image of light sticks

Commercially available light sticks contain a solution in a glass vial. When the vial is broken, a second solution mixes with the first and light (chemiluminescence) is generated. Different dyes give off different colors when they are caused to fluoresce by the light of the chemiluminescent reaction. (Photo: American Chemical Society)


chemiluminescence - a chemical reaction that gives off energy in the form of light instead of heat

chemoautotroph - an organism that utilizes oxidation of inorganic chemicals for its energy and carbon from inorganic carbon dioxide for cell growth; these organisms are also called chemolithotrophs

chemocline - a sharp gradient in chemical concentration

chemokinesis - the response by a motile cell to a soluble chemical that involves an increase or decrease in speed, or frequency of movement, or a change in the frequency or magnitude of turning behavior

chemoorganotroph - an organism that obtains energy from the oxidation of organic compounds and cellular carbon from preformed organic compounds

chemoreceptor - a receptor that is stimulated by the presence of certain chemical substances

chemosynthesis - the process whereby chemical energy is used to synthesize organic compounds from inorganic compounds, e.g., the oxidation of ammonia to nitrite by nitrifying bacteria

chemotaxis - a unidirectional response of motile cells or organisms in which the direction of movement is affected by the gradient of a diffusible substance

chemotrophs - organisms (usually bacteria) that derive energy from inorganic reactions; also known as chemosynthetic organisms

chi-square - a statistical technique whereby variables are categorized to determine whether a distribution of scores is due to chance or experimental factors

chi-square distribution - a distribution in which a variable is distributed like the sum of the the squares of any given independent random variable, each of which has a normal distribution with a mean of zero and a variance of one

chi-square test - a statistical test used to compare observed data with data expected to be obtained according to a specific null hypothesis. The chi-square tests the null hypothesis which states that there is no significant difference between the expected and observed result

Chile Margin Triple Junction (CMTJ) - the only presently active ridge-trench collision where the overriding plate is composed of continental lithosphere. Three tectonic plates meet here at the southern coast of Chile (46.5°S, 75.5°W): the South American Plate, the Nazca Plate, and the Antarctic Plate. The Chile Margin Triple Junction is the only known location on Earth that can co-host every known form of deep-sea chemosynthetic ecosystem: hydrothermal vents, cold seeps, and oxygen minimum zones; also called "Chile Triple Junction (CTJ)"

chimaera - a cartilagenous fish that has a compressed body and rodent-like teeth. Chimaeras are closely related to sharks and rays (class Chondrichthyes, subclass Holocephali), but have larger heads and eyes, the mouth is more towards the front of the head, the gills are protected by a gill cover, the skin is smooth, and most species have a whip-like tail; also called ghost sharks or ratfish

chimera - the individual produced by grafting an embryonic part of one individual onto an embryo of either the same or of a different species

chitin - a polysaccharide made up of chains of N-acetyl-D-glucosamine, a derivative of glucose. Chitin is structurally very similar to cellulose and serves to strengthen the supporting structures of various invertebrates. It also occurs in fungi

Image of a chiton

A dorsal view of a chiton shell. Chitons are distinguished from all other mollusks by the presence of their convex shell, which is divided into eight articulating plates (valves). (Photo: Rick Gillis, Ph.D., Biology Dept., University of Wisconsin-La Crosse)


chiton - a marine mollusk of the Subclass Polyplacophora, which contains about 600 species of sedentary animals commonly known as chitons.They are found from shallow waters to depths of about 400 m. A chiton has a broad foot and a shell consisting of eight overlapping plates

chlorocruorin - a greenish iron-containing respiratory pigment dissolved in the blood plasma of certain marine polychaete worms. It may give the green color to the blood of these worms

chlorofluorocarbons (CFC) - gases that can be dissociated by solar radiation, which release chlorine, which in turn destroys ozone

chlorophyll - a green pigment present in green plants and cyanobacteria. Chlorophyll is essential in the transformation of light energy to chemical energy in photosynthesis

chlorophyll a - the major photosynthetic pigment found in all oxygen-evolving photosynthetic organisms (higher plants, and red and green algae)

chlorophyll b - the chlorophyll generally characteristic of higher plants and green algae .It is absent in other types of algae

chlorophyll c - the chlorophyll present in brown algae, diatoms, and flagellates

chlorophyll d - the chlorophyll present in red algae, together with chlorophyll a

chloroplast - a disk-like organelle with a double membrane, found in some protists and all green plant cells, that contains chlorophyll and is the site of photosynthesis

Image of plant with chlorosis

Disease symptoms (necrotic lesions surrounded by chlorosis) caused by a bacterial infection. (Photo: Dr. Roger Thilminy and Sheng Yang He, Michigan State University)


chlorosis - the yellowing or bleaching of plant tissues due to the loss of chlorophyll or failure of chlorophyll synthesis. It can be caused by insuffient light or nutrients, and also by certain diseases

Diagram of choanocyte

Diagram of choanocyte. The flagella create water currents that bring nutrients into the interior of a sponge. (Diagram: U.S. Environmental Protection Agency)


choanocyte (collar cell) - a flagellated cell that lines the interior of the central cavity (spongocoel) of a sponge. Choanocytes have a tubular collar with an extended flagellum that faces the spongocoel and creates currents that force water into the interstices of the sponge. Suspended food particles, such as plankton, are trapped by the choanocytes and passed to an amoebocyte that carries the food to other cells

choanocyte chamber - in sponges, a cavity lined with choanocytes and located between incurrent and excurrent systems

choanoderm - in sponges, a surface lined with choanocytes

choanosome - the internal region of a sponge, including the choanocyte chambers

Image of a manta ray

A manta ray, a member of the class Chondrichtyes. (Photo: NOAA)


Chondrichthyes - the class of cartilaginous fishes that includes sharks, rays, skates, and chimaeras. Their skeleton is composed of cartilage, not bone

chondriome - refers to all of the mitochondria in a cell

Image of humpback whale (phylum Chordata)

The phylum Chordata includes the mammals such as this large humback whale (Megaptera novaeangliae).


Chordata - an animal phylum that includes sea squirts (tunicates), lampreys and hagfishes, fishes, amphibians, reptiles, birds and mammals. Many species of marine chordates play prominent roles in the ecology of coral reef ecosystems

chorion - a thick, vascularized extra-embryonic membrane of amniote embryos that forms around the entire undersurface of the eggshell in birds and reptiles, and in direct contact with the uterine wall in mammals. It unites with the allantois to form the major structure for exchange between the embryo and the outside (birds and reptiles) or the maternal circulation (mammals)

chorology - the study of the spatial distribution of organisms

chromatid - each of a pair of identical DNA molecules after DNA replication, joined at the centromere

chromatin - replicated DNA and associated proteins; highly folded ribbon-like complexes of deoxyribonucleic acid (DNA) and a class of proteins called histones; protein/DNA complex making the chromosome

Image of a flounder

This flounder is rarely noticed unless disturbed because of its remarkable ability to change color to match the substrate, by concentating or dispersing pigment granules in its chromatophores.


chromatophore - a cell whose cytoplasm contains pigment granules that can be rapidly concentrated or dispersed, producing an overall effect of altering the color, color pattern or tone of the whole or part of an animal

chromophore - a part of a molecule that absorbs certain wavelengths of visible light and reflects or transmits others; that part of a molecule that is responsible for its color

chromoplast - a plastid containing pigments other than chlorophyll, usually yellow or orange carotenoids

chromoprotein (CP) - any of a group of conjugated proteins in which the protein is joined to a pigmented prosthetic group. An example of a chromoprotein is hemoglobin, which contains heme, the iron-containing molecule that makes oxygenated blood appear red

chromosomal aberration - any change in chromosome structure or number. Although chromosomal abberations can be mechanisms for enhancing genetic diversity, such alterations are usually deleterious or ill-adaptive; includes deficiency, duplication, inversion, translocation, aneuploidy, polyploidy, or any other change from the normal pattern

chromosomal deletion - a mutation resulting from the loss of a small segment of DNA

chromosomal mutation - a mutation involving a long segment of DNA. These mutations can involve deletions, insertions, or inversions of sections of DNA. In some cases, deleted sections may attach to other chromosomes, disrupting both the chromosomes that loses the DNA and the one that gains it; any type of change in the chromosome structure or number

Image of chromosomes

Highly magnified view of cell chromosomes.


chromosome - one of the threadlike "packages" of genes and other DNA in the nucleus of a cell. Different species of organisms have different numbers of chromosomes. In sexually reproducing species, each parent contributes one chromosome of each pair, so offspring get half of their chromosomes from the maternal parent and half from the paternal parent. Bacterial cells do not possess a nucleus, therefore their chromosomes are located in the cellular cytoplasm

chronic - long term or frequently recurring

chronobiology - the field of biology concerned with the timing of biological events, especially repetitive or cyclic phenomena in individual organisms.

chronograph - an instrument for recording the moment of an event

chronology - the age-depth relationship in ice, sediment, or another deposit. Ages are usually measured for discrete samples, and the ages of intermediate samples are interpolated between samples with measured ages

chronometer - an instrument for measuring time

Image of barracuda head

Ciguatera food poisoning may be contracted by eating the flesh of a contaminated barracuda.


ciguatera - a food poisoning of humans caused by eating some species of tropical fishes whose flesh is contaminated with toxins obtained through the food chain

Image of a barracuda

Barracuda (Sphyraena sp.) are often the culprits in ciguatera food poisoning, caused by ciguatoxin. (Photo: Copyright Corel Corporation)


ciguatoxin - a toxin found in flesh of marine animals, especially some fishes, at some times, in some localities. It is probably of algal origin and causes paresthesia, gastrointestinal symptoms, neuromuscular blockade, and respiratory paralysis due to interference with membrane function

cilia - short, motile, generally microscopic, hairlike projections found on many protists and larvae of some invertebrates. Cilia are used for locomotion, the generation of a current, or filter feeding; A cilium is made up of microtubules and has basically the same internal structure as a flagellum. Movement is caused by the interactions of the microtubules. In higher animals, cilia are found projecting from cells that line certain tubes and passages, such as the tracheae (windpipe) of mammals

ciliary - relating to any cilia or hairlike processes; can relate to muscles concerned with visual focusing

Image of ciliated columnar eithileium cells

Pseudostratified ciliated columnar epithelium - the ciliated epithelium that lines the trachea (windpipe) of mammals. (Photo courtesy of Dr. Franklin S. Carman III, donated from URL: http://tooldoc.wncc.edu)


ciliated epithelium - any epithelium having motile cilia on the free surface

Image of a stalked ciliate

The stalked ciliate, Stentor. (Photo: Jon Houseman/BIODIDAC)


Ciliophora - a group of protists bearing cilia

cinclide - one of many blister-like openings in the lower part of the body column of some anemones, through which the animal expels long, thread-like acontia

circa - about; around

circadian - being, having, characterized by, or occurring in approximately 24 hour periods or cycles

circadian rhythm - the regular recurrence, in cycles of about 24 hours, of biological processes or activities

circinate - ring-shaped

circumesophageal nerve ring - anterior concentration of nervous tissue in several invertebrate groups, such as mollusks, annelid worms, sipunculids (peanut worms), and echiurans (spoon worms or innkeeper worms)

cirrus - a slender, flexible appendage or part of an organism, usually having a tactile function

cistron - a DNA sequence that codes for a specific polypeptide; an alternate name for a gene

citreous - lemon color

citric acid cycle - see: Krebs cycle

clade - a group of species with a common evolutionary ancestry

cladist - a systematist who attempts to classify life forms according to their evolutionary relationships, not just overall similarity

cladistic distance - the number of branching points between any two nodes on a phylogenetic tree

cladistic species - the concept of species in which a species is a lineage of populations between two phylogenetic branch points (speciation events)

cladistics - the systematic classification of groups of organisms on the basis of the order of their assumed divergence from ancestral species

cladogenesis - the evolutionary process whereby one species evolves into two or more species

cladogram - a tree-like diagram, resulting from a cladistic analysis, which depicts a hypothetical branching sequence of lineages leading to the taxa under consideration. The points of branching within a cladogram are called nodes. All taxa occur at the endpoints of the cladogram

Image of ventral side of stingray

NOAA scientist measuring the length of a rays's clasper.


clasper - a rod-like modification of the pelvic fin of a male elasmobranch that is used to transfer sperm into the female during mating

class - in taxonomy, a category just beneath the phylum and above the order; a group of related orders

Graphic of a histogram

A histogram in which the population of data are grouped into non-overlapping class intervals.


class interval - one of the ranges into which data in a frequency distribution table (or histogram) are binned. The ends of a class interval are called class limits, and the middle of an interval is called a class mark. In plotting a histogram, begin by dividing the range of all values into non-overlapping class intervals, in such a way that every piece of data is contained in some class interval

classical conditioning - a form of associative learning, in which an animal recognizes that two or more events are related. The animal performs a behavior in response to a substitute stimulus rather than the normal stimulus

classification - a system of nested hierarchical categories used to efficiently store information about biological diversity

clathrate - resembling an open latticework

clavate - club-shaped

clean development mechanism (CDM) - a mechanism under the Kyoto Protocol designed to assist developed countries in meeting their emissions reduction targets

Clean Water Act (CWA) - an act passed by the U.S. Congress to control water pollution. Growing public awareness and concern for controlling water pollution led to enactment of the Federal Water Pollution Control Act Amendments of 1972. As amended in 1977, this law became commonly known as the Clean Water Act. The Act established the basic structure for regulating discharges of pollutants into the waters of the United States. It gave EPA the authority to implement pollution control programs such as setting wastewater standards for industry. The Clean Water Act also continued requirements to set water quality standards for all contaminants in surface waters. The Act made it unlawful for any person to discharge any pollutant from a point source into navigable waters, unless a permit was obtained under its provisions. It also funded the construction of sewage treatment plants under the construction grants program and recognized the need for planning to address the critical problems posed by nonpoint source pollution

Image of a cleaning shrimp

Pederson's Cleaning Shrimp (Periclimenes pedersoni) on a reef in the Virgin Islands. This small (to 1 inch) shrimp favors habitat and a steady food supply offered by Ringed and Giant Caribbean anemones.


cleaning behavior - mutualistic behavior in which larger animals, usually fishes, permit smaller animals, usually other species of fishes or invertebrates, to clean them of external parasites

cleaning station - a site visited by fishes where, in a mutually symbiotic relationship, cleaning shrimp or fish remove parasites from their bodies

Image of cell undergoing cleavage

A four-cell stage of a cleaving sea urchin embryo. (Photo: Copyright Dr. Leland Johnson, Augustana College, Illinois)


cleavage - the early mitotic cellular divisions of the fertilized egg (zygote)

client - a software program that is used to contact and obtain data from a server software program on another computer, often across a great distance. Each client program is designed to work with one or more specific kinds of server programs, and each server requires a specific kind of Client. A web browser is a specific kind of client

climate - long-term characteristics of weather

climate change - the long-term fluctuations in temperature, precipitation, wind, and all other aspects of the Earth's climate. It is also defined by the United Nations Convention on Climate Change as "change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods"; an observed change in the prevailing or average weather conditions

climate change adaptation (CCA) - actions taken to help society, communities, and ecosystems moderate, cope with, or take advantage of actual or expected changes in climate conditions. Adaptation can reduce vulnerability, both in the short and long term

climate threats - the overall change in environmental conditions (e.g., increasing sea surface temperature) resulting from changes in climate due to increasing global greenhouse gas concentrations.

climate variability - changes (variability/trends) in the long-term characteristics of weather; the normal range of climatic variables over a specific climatic period

climate-induced bleaching - coral bleaching as a result of changing climate patterns, e.g., temperature

climatic variable - any climate parameter that changes over a period of time; e.g., temperature, rainfall, humidity

climax - the final stage in ecological succession that is able to persist in the absence of environmental change

climax community - a relatively stable community which is in equilibrium with the existing natural environment

clinal speciation - a form of allopatric speciation in which a vicariant event interrupts gene flow in a former cline

cline - the gradual variation, in a character of a species, in geographical space

cloaca - the common passage for fecal, urinary and reproductive discharge in most lower vertebrates

clone - an individual genetically identical to the parent organism, created by the splitting off or budding of cells from the parent organism

clone cells - a group of genetically identical cells all descended from a single common ancestral cell by mitosis in eukaryotes, or by binary fission in prokaryotes. Clone cells also include populations of recombinant DNA molecules all carrying the same inserted sequence of bases

cloned DNA - exact copies of DNA segments prepared by using recombinant DNA technology

cloning - the process of asexual reproduction in an otherwise multicellular organism

cloning vector - DNA molecule originating from a virus, a plasmid, or the cell of a higher organism into which another DNA fragment of appropriate size can be integrated without loss of the vector's capacity for self-replication; vectors introduce foreign DNA into host cells, where the DNA can be reproduced in large quantities. Examples are plasmids, cosmids, and yeast artificial chromosomes; vectors are often recombinant molecules containing DNA sequences from several sources

closed circuit scuba - a diving apparatus which allows divers to re-breathe exhaled air after removal of carbon dioxide and addition of supplemental oxygen. It is not generally used by recreational scuba divers

closed circulatory system - a circulatory system in which blood flows through blood vessels at all times. Blood flows from arteries to capillaries and through veins, but the tissues surrounding the vessels are not directly bathed by blood. Some invertebrates and all vertebrates have closed circulatory systems

closed system - a system in which no matter or energy can leave or enter from the outside

clupeoid fish - any soft-rayed, bony fish species belonging to the order Clupeiformes. These include herrings, shads, wolf herrings, sardines, and anchovies

clupeoid fish poisoning - a very serious form of fish poisoning caused by eating clupeotoxic fishes; also called clupeotoxism

clupeotoxic fish - fishes in the orders Clupeiformes (herrings and herring-like fishes), and Elopiformes (ladyfishes and tarpons) whose flesh might contain a toxin, clupeotoxin, by ingesting certain dinoflagellates which contain the toxin

clupeotoxin - the poison in clupeotoxic fishes. It is a neurotoxin, palytoxin, found in marine dinoflagellates and presumably ingested by the fish

cluster analysis - a multivariate statistical technique for solving classification problems. The object is to sort items into groups such that the degree of association is strong between members of the same cluster and weak between members of different clusters

cnida - an organelle located in cnidocytes that is capable of eversion

Image of cnidarian, a Dahlia anemone

An Atlantic coast cnidarian, a dahlia sea anemone (Tealia sp.) (Photo: Andy Bruckner)


Cnidaria - a multicellular animal phylum, with a tissue grade of construction, that contains the stony (hard) corals, anemones, sea fans, sea pens, hydroids, and jellyfish

cnidocyte - a stinging cell of jellyfish, hydroids, sea anemones and corals. The cnidocyte contains the eversible cnida. The most common type of cnidocyte is the stinging structure known as the nematocyst. Nematocysts are located throughout the epidermis, but are especially abundant on the tentacles

cnidoglandular band - in cnidarians, the central ridge of a mesenteric filament which beatrs nematocysts and gland cells that secrete digestive enzymes

Image of tissue section showing cnidosac

Section through the ceras of Aeolidiopsis ransoni showing the cnidosac with three nematocysts. (Photo: Dr. Bill Rudman)


cnidosac - a sac located in a ceras of a nudibranch gastropod which contains undischarged nematocysts (obtained through feeding upon cnidarians) passed from the slug's digestive system. When a predator attacks the nudibranch, the nematocysts may discharge as a defensive mechanism

co-adaptation - development and maintenance of advantageous traits benefiting one or both parties in a two-species interaction; evolution of characteristics of two or more species to their mutual advantage; predator-prey and cleaning symbioses are examples of such evolving interactions in marine communities

co-management - the sharing of authority, responsibility, and benefits between government and local communities in the management of natural resources

coacervate - an aggregate of colloidal droplets held together by electrostatic forces. Coacervate droplets may contain a mixture of organic compounds. One theory of the evolution of life is that the formation of coacervates in the primeval soup was a step towards the development of cells

coalesce - to come together so as to form one whole; to fuse

Image of Hawaiian coast

Rainbow over Hawaii, HI coast (Photo: Dr. James P. McVey, NOAA Sea Grant Program)


coastal area - the areas of land and sea bordering the shoreline and extending seaward through the breaker zone. Coastal areas throughout the world are under enormous environmental stress, which is caused by a wide range of factors, including pollution and the destruction and deterioration of marine habitats

Image of flooded streets

A coastal storm leaves flooded streets in its wake. (Photo: U.S. Army Corps of Engineers)


coastal flooding - flooding that occurs from storms where water is driven onto land from an adjacent body of water

coastal reef - a coral reef occurring near and parallel to a coastline

Image of Oregon coast

Spectacular Oregon coastline. (Photo: Rear Admiral Harley D. Nygren, NOAA Corps)


coastal zone - coastal waters and adjacent lands that exert a measurable influence on the uses of the oceans and their living and nonliving resources

Coastal Zone Color Scanner (CZCS) - a scanning radiometer with six spectral channels centered at 0.443, 0.520, 0.550, 0.670, 0.750 and 11.5 micrometers and selected to allow measurement of ocean color and temperature, suspended sediment and chlorophyll concentrations, and ocean pollutants

Coastal Zone Management Act - passed in 1972, the CZMA provides for management of shoreline areas that may include coral reefs

Image of capsid of cypovirus

A single coat protein (capsid) of a cypovirus surrounded by a loose polyhedrin matrix. (Photo: Dr. Hans Ackermann, Medical Faculty, Laval University, Quebec, Canada)


coat protein - the coating protein that encloses the nucleic acid core of a viral particle; the capsid

coccidia - microscopic, spore-forming, obligate, intracellular single-celled parasites belonging to the phylum Apicomplexa. Coccidian parasites infect the intestinal tracts of animals, causing the disease "coccidiosis"

Image of coccus bacteria

Coccus bacteria. (Photo: Robert W. Bowker, Glendale Community College Glendale, AZ)


coccus - a bacterium with a spherical shape

Code - in taxonomy, the International Code of Zoological Nomenclature. An authoritative document containing a system of rules and recommendations to be followed in giving a scientific name to an animal or animal group

coding - the specification of a peptide sequence by the code contained in DNA molecules

coding region - a sequence of DNA, bounded by start and stop codons, which consists of a series of nucleotide bases that gives rise to mRNA (messenger RNA) that will be translated into the specific amino acids of the protein product

coding sequence - that portion of a gene which directly specifies the amino acid sequence of its protein product

coding strand - the strand of duplex DNA which contains the same base sequence (after substituting Uracil for Thymine) found in the mRNA molecule resulting from transcription of that segment of DNA., known as the sense strand. The mRNA molecule is transcribed from the other strand, known as the template or antisense strand

Diagram of RNA codons

RNA codons. A = adenine; C = cytosine; G = guanine; U = uracil. (Diagram: NIH/Human Genome Project)


codon - three bases in a DNA or RNA sequence which specify a single amino acid

coefficient - a number expressing the amount of some change or effect under certain conditions

coefficient of faunal similarity (CFS) - The CFS compares the fauna of one area with that of another. CFS = 2C/(a+b), where C = the number of species in common between two areas, a = the number of species in the first area, and b = the number of species in the second area. The higher the CFS, the greater the resemblance

coefficient of variation - in statistics, it refers to the standard deviation of a distribution divided by the distribution's mean, providing a standardized measure of the variation in a distribution, which does not increase simply because the mean itself increases or because the units of measurement change

coefficient of variation (c.v.) - the standard deviation divided by the mean and multiplied by 100

Coelenterata - an older name for the phylum Cnidaria

coelenteron - the gastrovascular (digestive) cavity of a cnidarian or ctenophore

coelobite - an organism that lives in pores and spaces within a reef

coeloblastula - a larval form associated with oviparous development, with a cytologically undifferentiated central region, and an even distribution of small flagella. Coeloblastulae are found in sponges, brachiopods and other invertebrate groups

coelom - an internal fluid-filled body cavity within a coelomate organism. It lies between the gut and the outer body wall, and is lined entirely with tissue (peritoneum) derived from the mesoderm. Most internal organs are located within the coelom. The structure and development of the coelom is an important taxonomic character for recognizing major groups of animals

coelozoic - living in the lumen of a hollow organ, such as the intestine, gall bladder, urinary tract, etc

coenecium - a branching tubular network inhabited by pterobranch (Hemichordata) colonies that is secreted from glands in the oral shields of the zooids

coenenchyme - all of the mesenchymal tissue, perforated with channels, that is common to all polyps of a colonial cnidarian

coenocline - a sequence of communities along an environmental gradient

coenosarc - the living tissue of a cnidarian polyp, consisting of the outer, nonciliated epidermis and the inner, ciliated gastrodermis with the thin, acellular meoglea in between. The coenosarc connects the coral polyps of a coral colony. It spreads along the surface of the calcareous exoskeleton

coenosteum - the common surface of corallum between calices; the skeleton deposited between the corallite walls of a colonial scleractinian coral

coenosteum pit - the point of insertion or commencement of septa in some corals

coenzyme - an organic nonprotein molecule that binds with the protein molecule to form the active enzyme

coevolution - a change in the genetic composition of one species (or infraspecific group) in response to a genetic change in another, i.e. two or more species evolving, each in response to the other

cofactor - a nonprotein substance required for certain enzymes to function. Cofactors can be co-enzymes or metallic ions

cohort - individuals all of the same age

cohort - in taxonomy, a taxonomic rank between infraclass and superorder

COI - a protein which ranges in length from 510-530 amino acids among different animal species

cold front - in meteorology, a mass of cold air moving toward a mass of warm air. Strong winds and rain typically accompany a cold front

cold water - temperature regime usually between 4º – 13º C, and not exceeding 20° C. This is not an exact definition, and is meant only to distinguish between cold-water and tropical warm-water coral environments

cold-water coral ecosystem - a large aggregation of cold-water corals with their associated fauna in terms of spatial coverage at a given locality

Image of fish kill

A coliform-caused fish kill. Fecal coliforms originate from sewer overflows, septic tank seepage and animal defecation. They are indicators of fecal contamination which could also contain bacteria and viruses responsible for cholera and typhoid infections, hepatitis and gastroenteritis. (Photo: Pine River Shire Environmental Services, Australia)


coliform bacteria - bacteria whose presence in water is an indicator of pollution and of potentially dangerous contamination

collagen - the protein substance of the collagenous fibers (white fibers) of skin, tendon, bone, cartilage and all other connective tissue. Collagen also serves as skeletal support in some sponges

collagenous - producing or containing collagen

collagenous fiber - white connective tissue fiber that occurs in bundles. They possess a high tensile strength and make up the principal element of irregular connective tissue, tendons, and aponeuroses, and occur in the matrix of cartilage and bone tissue

collar cell - a specialized cell found in the epithelia of mesenterial filaments and the actinopharynx; the choanocyte of sponges.

collection - an assemblage of specimens compiled and maintained for purposes of study and/or display

collection - an assemblage of specimens compiled and maintained for purposes of study and/or display

collenchyme - in cnidarians, mesenchyme with sparse cellular components

collencytes - a contractile, collagen-secreting amoebocyte in sponges

Graphic of a colloblast

Colloblast discharge organ of ctenophorans (comb jellies). (Image: Livingstone, Copyright BIODIDAC)


colloblast - a cell that discharges a sticky filament upon contact with a prey organism. Colloblasts are found in the tentacles of ctenophores (comb jellies). As the tentacles are dragged through the water, the colloblasts discharge and capture prey

colloid - a stable suspension of particles that, though larger than in a true solution, do not settle out

colonial - a level of cellular organization intermediate between unicellular and multicellular; refers to organisms that occur in a fixed location, with one generation growing on top previous generations, as in coral reefs; types of animal that are organized into associations of incompletely separated individuals; eg, Portuguese man o' war, sponges and corals; in plants, describes cloning by asexual reproduction in which seemingly separate plants grew from rhizomes, stolons, or roots of a single or neighboring parent plant

colonial coral - a coral composed of many individuals

colonization - a movement of individuals or propagules of a species to a new territory

colonized hardbottom - a substrate formed by the deposition of calcium carbonate by reef building and other organisms. Habitats within this category have some colonization by live coral

colony - a group of the same kind of animals, plants, or one-celled organisms living or growing together

color - a quality of light, depending on its wavelength. Perceived color (or visual color) is the quality of light emission as conveyed by the eye, i.e., the visual perception of light that enables humans and other organisms to differentiate between wavelengths of the visible spectrum

colorimeter - an instrument for measuring and determining color

coloumb - unit of electrical charge of one ampere over period of one second

Image of columella inside oyster drill

The columella inside a Strombus oyster drill. (Photo: Jesuit Dallas Museum)


columella - any small column-like structure in various plants and animals, often forming the central axis of development for the organism as a whole, or an anatomical structure; the thickened axial pillar around which the whorls of gastropods are constructed; the central axis of a corallite; the central structure of the calyx formed by fusion of the septa

column - the cylindrical body of an anthozoan polyp

columnar - column-shaped

columnar colony - a coral colony formed into one or more columns

comb row - a longitudinal line of ctenes on the epidermis of ctenophores (comb jellies)

commensal - having benefit for one member of a two-species association but neither positive nor negative effect on the other

commercial extinction - the decline in the population of a wild species, used as a resource, to a level where it is no longer profitable to harvest the species

Commission - refers to the International Commission on Zoological Nomenclature (ICZN)

common ancestor - the most recent ancestral form or species from which two different species evolved

communication network - telecommunications infrastructure that transfers data from observing systems to data centers, and then to end users

community - a naturally occurring assemblage of organisms that live in the same environment and are mutually sustaining and interdependent; a group of populations that interact in time and space

community-based ecosystem management - a process whereby non-government organizations, community groups, or individuals participate in long-term management of selected species, habitats, or ecosystem processes with the ultimate goal of improving management of ecosystems and natural resources

Compact Airborne Spectrographic Imager (CASI) - a digital airborne multispectral sensor

compact branching - a growth pattern where the coral branches are close together

compensation depth - the depth in the ocean at which the difference between the oxygen produced by algae through photosynthesis and that consumed by them through respiration is zero, i.e., net oxygen production is zero

Image of sweeper tentacles

Sweeper tentacles from a Galaxia colony. The stinging cells kill neighboring "non-self" corals in the competion for space. Mesenterial filaments which dissolve neighboring non-self corals are another means of competitive tactics by scleractinian corals. (Photo: Copyright 2001 Robert C. Michelson)


competition - a biological interaction that can limit population growth. Competition occurs when two or more populations vie for the same limited resource

competitive exclusion - the principle that when the populations of two species compete for resources, one will use the resources more efficiently, therefore outcompete and eventually eliminate the other population

competitive release - the expansion of a species' ecological niche, associated with the lack of competition with other species

complement - the complement of a nucleic acid sequence replaces each base by its complementary base: adenine (A) by thymine (T), cytosine (C) by guanine (G), and vice versa. In RNA, adenine is paired not with thymine but with uracil (U)

complementarity - the relationship between the two strands of a double helix of DNA. Thymine in one strand pairs with adenine in the other strand, and cytosine in one strand pairs with guanine in the other strand

complementary base pair - the specific matching of purine and pyrimidine base pairs in nucleic acids. This matching occurs because the structure of one base precisely fits with, and bonds to, another specific base. In DNA, adenine and thymine are complementary and form a base pair, as do cytosine and guanine. In pairing between DNA and RNA, adenine and uracil are complementary, and cytosine and guanine are complementary

complementary DNA (cDNA) - a strong, cloned DNA copy of otherwise fragile mRNA, made using reverse transcriptase. A cDNA is so-called because its sequence is the complement of the original mRNA sequence. However, when double-stranded cDNA is synthesized, it contains both the original sequence and its complement

complementary nucleotide - a member of the pairs adenine-thymine, adenine-uracil, and guanine-cytosine that have the ability to hydrogen bond to one another

complementary resources - a pair of resources for which consumption by the consumer of one resource reduces its requirement for the other

complete protein - a protein that has all of the essential amino acids and in the correct proportions

complexity - in ecology, the number of species at each trophic level and the number of trophic levels in a community; in molecular genetics, used to describe a DNA molecule or a mixture of DNA molecules. It is the length of the nucleotide sequence without including any sequence repetition

compound - a material made up of two or more elements combined in a fixed ratio

compound chromatophore - a chromatophore that contains more than one kind of pigment

compound eye - the eye of arthropods, most highly developed in insects and crustaceans. It consists of a group of functionally related visual elements (ommatidia), each having its own refractive system and each forming a portion of an image

Image of a garibaldi

The compressed body shape of a garibaldi. (Photo: Copyright Corel Corporation)


compressed - a body shape which is flattened laterally, bringing the right and left sides closer together, e.g., a butterfly fish or a flounder

compressed air - air compressed to a pressure higher than the surrounding atmospheric pressure (ambient pressure)

compression - in information technology, decreasing the size of stored information by reducing the representation of the information without significantly diminishing the information itself, usually by removing redundancies. The information requires decompression upon retrieval. Lossless compression allows the original data to be recreated exactly. Lossy compression sacrifices some accuracy to achieve greater compression

conchiform - shell-shaped

conchology - the study of shells

confidence interval - the probability, based on statistics, that a number will be between an upper and lower limit

confluent - joined together

congenor - a member of the same genus

conger eel - any species of eel in the family Congridae. Conger eels have a thick cylindrical body and tapering snout. They possess a smooth and scaleless skin and large pectoral fins. They are much less common than moray eels in coral reef communities. During the day they tend to hide in crevices and holes under rocks or coral, or burrow into sand. They emerge at night to feed

conjugated protein - a protein complex combining amino acids with other substances

Image of green algae

Spirogyra is a filamentous green alga. Certain filaments in a loose parallel bundle of Spirogyra assume the female role, and others the male. The cells of adjacent filaments develop tubular extensions which grow towards one another and eventually fuse to form a continuous tube between the cells. Meanwhile the contents of each cell have formed a round sphere. The spheres from the male filament squeeze their way down the connecting tubes to fuse with a sphere of the female cell in the other filament. The result of this sexual union is the formation of a zygote (zygospore) within the chambers of the female filament. After a dormant period, the zygotes undergo meiosis and germinate, resulting in new filaments. (Photo: Wappinger Schools)


conjugation - a process of sexual reproduction whereby two cells come in contact and exchange genetic material. In prokaryotes and unicellular agae, the transfer is a one-way process. The union of two bacterial cells, during which chromosomal material is transferred from the donor to the recipient cell. Conjugation in protozoans is a two-way process, genetic material is passed between each conjugant

conopeptide - a family of molecules found in the venom of species of marine cone shell snails (Conus sp) that can act as an analgesic and alleviate pain.One particular group, the omega-conopeptides, blocks channels on nerve cells that transport calcium ions and thereby interfering with the production of neurotransmittors. Synthetic copies of conopeptides from the magician's cone shell, Conus magus, are used to make the drug Prialt, generally known as ziconotide

conotoxin - a toxin produced by cone-shell snails of the genus Conus

Conservation - under the NOAA Coral Reef Conservation program, the term 'conservation' means the use of methods and procedures necessary to preserve or sustain corals and associated species as diverse, viable, and self-perpetuating coral reef ecosystems, including all activities associated with resource management, such as assessment, conservation, protection, restoration, sustainable use, and management of habitat; mapping; habitat monitoring; assistance in the development of management stategies for marine protected areas and marine resourses consistent with the National Marine Sanctuaries Act (16 U.S.C. 1431 et seq.) and the Magnuson-Stevens Fishery Conservation and Management Act (16 U.S.C. 1801 et seq.); law enforcement; conflict resolution initiatives; community outreach and education; and that promote safe and ecologically sound navigation

conservation - the political/social/economic process by which the environment is protected and resources are used wisely

conservation biology - a multidisciplinary science that deals with the conservation of genes, species, populations, communities, and ecosystems that make up the Earth's biodiversity. Its goals are to investigate human impacts of biodiversity and to develop approaches to prevent extinction of species through stewardship of entire biological communities

conserved name - in taxonomy, a name otherwise unavailable or invalid that the International Commission on Zoological Nomenclature, by the use of it Plenary Power, has enabled to be used as a valid name by removal of the known obstacles to such use

consexual - of the same sex

conspecific - of the same species

consumer - an organism which must consume other organisms (living or dead) in order to satisfy its energy needs

contaminant - an undesirable substance not normally present, or an usually high concentration of a naturally occurring substance in the environment; a substance in water that might adversely affect the health and welfare of the biota

Content Standard for Digital Geospatial Metadata - provides a common set of terminology and definitions for the documentation of digital geospatial data. The standard establishes the names of data elements and compound elements (groups of data elements) to be used for these purposes, the definitions of these compound elements and data elements, and information about the values that are to be provided for the data elements

contiguous - adjacent or touching; having a common boundary; adjoining; connected without a break

contiguous habitats - refers to habitats that are connected to each other by sharing a common boundary

continental margin - the water-covered edges of continents consisting of the continental shelf, the continental slope, and the continental rise

continental rise - the enormous wedge of sediment deposited at the base of the continental slope

continental shelf - the shallow, near-horizontal sea floor extending from the coast to the upper continental slope

continental slope - the sloping sea bottom of the continental margin that begins at a depth of about 100 to 150 m at the shelf edge and ends at the top of the continental rise or in a deep-sea trench

continuum - a continuous set of data for which each data point is related to the adjacent point; a gradual or imperceptible intergradation between two or more extreme values

contour - on a map or chart, a line connecting points of equal surface value

contour interval - the difference in surface values between contours

controlled environment - the environment in which parameters, such as light, temperature, salinity, etc., are fully controlled

controlled experiment - a scientific experiment, in which results from an experimental group with variable conditions, is compared with a control group with nonvariable conditions

convection current - a movement of air or water caused by changes in density or thermal gradients

Convention on International Trade in Endangered Species (CITES) - the ‘Washington’ Convention on International Trade in Endangered Species of Wild Fauna and Flora, more commonly known as CITES, aims to protect certain plants and animals by regulating and monitoring their international trade to prevent it reaching unsustainable levels. There are more than 150 Parties to the Convention. The CITES Secretariat is administered by the United Nations Environment Programme (UNEP). CITES regulates international trade in over 30,000 species, of which approximately 25,000 are plants

convergence - come together and meet at a point

convergent evolution - the development of superficially similar structures in unrelated organisms, e.g., the wings of insects and birds

coordinate taxon - in cladistics, a group within a monophyletic lineage at the same branching level as another. Therefore, it requires equivalent taxonomic rank in the Linnean classification hierarchy

copepod - any of a large subclass (Copepoda) of usually minute freshwater and marine crustaceans that form an important element of the zooplankton in the marine environment and in some fresh waters. A common feature uniting all the copepod orders is a single simple eye in the middle of the head, at least in the larval stage. The cephalosome, a shield over the head and some thoracic segments distinguishes the free living forms from parasitic ones. Some species are ectoparasites of marine fishes

copepodid - postnaupliar developmental stages of copepods

coprophagous - pertains to feeding on fecal matter

Image of finger coral

Finger coral (Porites compressa) in Hawaii (Photo: M. White)


coral - a general term used to describe a group of cnidarians; indicates the presence of skeletal material that is embedded in the living tissue or encloses the animal altogether

coral assemblage - a group of corals

Image of bleached coral in the Florida Keys

Bleached Acropora coral in Florida Keys (Photo: Larry Benvenuti)


coral bleaching - the process in which a coral polyp, under environmental stress, expels its symbiotic zooxanthellae from its body. The affected coral colony appears whitened

Image of plot of ocean areas with elevated water temperatures

Section of a graphic depicting areas of elevated ocean temperatures that may result in coral bleaching events.


coral bleaching hotspot - a region of sea surface temperature (SST) that exceeds the climatological maximum for a region by 1 deg C or more. These conditions may cause sufficient stress to coral reefs to result in coral bleaching

Coral Bleaching HotSpot monitoring program - a NOAA program that uses satellite and in situ monitoring stations to monitor high sea surface temperature events and to analyze conditions that may lead to coral bleaching

Coral Disease and Health Consortium (CDHC) - in response to the dramatic increase of coral diseases observed over recent years, the U.S. Coral Reef task force (2002) recommended the creation of the CDHC from a cross-section of internationally recognized experts in coral diseases, biomedical and veterinary sciences, pathology, chemistry, biology, biotechnology, and marine management. It organizes and coordinates the scientific resources of the U.S. and its territories to meet the challenge of globally declining coral reefs

coral growth line - a minute growth line on the outer surfaces of corals that have a calcified outer wall. The carbonate is produced by zooxanthellae which create a series of diurnal growth increments

Coral Health And Monitoring Program (CHAMP) - a NOAA program whose mission is to provide services to help improve and sustain coral reef health throughout the world. Long term goals are: establish an international network of coral reef researchers for the purpose of sharing knowledge and information on coral health and monitoring; provide near real-time data products derived from satellite images and monitoring stations at coral reef areas; provide a data repository for historical data collected from coral reef areas; and add to the general fund of coral reef knowledge

Coral Literature, Education & Outreach (CLEO) - the CLEO project is designed to provide easy access to gray literature and pre-1990's literature on the coral reef environments near the Coral Reef Early Warning System (CREWS) monitoring stations to support education, research and management objectives. The Education modules leverage techniques developed at NOAA/AOML in the Explorer of the Seas, Coral Health and Monitoring and CREWS programs under which knowledge transfer of oceanographic instrumentaion and coral reef processes have been developed. Education modules for middle school students engage the students in oceanographic instrumentation, classroom experiments and use of data, and the live Coral Cam observations

coral necropolis - an area on the ocean floor covered mostly by (dead) coral skeletons

Coral Parks Program (CPP) - a global initiative that supports existing Coral Parks, assists in the establishment on new Coral Parks, and engages divers and the dive industry in coral reef protection. CPP is an initiative of The Coral Reef Alliance, a non-profit organization dedicated to keeping coral reefs alive around the world

Coral Point Count with Excel extensions (CPCe) - a software program distributed by the National Coral Reef Institute that provides a tool for the estimation of benthic habitat cover using underwater images. The coverage can be estimated using the random point count method, and areas can also be traced, digitized, and calculated via image calibration. More information can be found at www.nova.edu/ocean/cpce

coral probiotic hypothesis - "this hypothesis posits that a dynamic relationship exists between symbiotic microorganisms and environmental conditions which brings about the selection of the most advantageous coral holobiont. Changing their microbial partners would allow the corals to adapt to changing environmental conditions more rapidly (days to weeks) than via mutation and selection (many years). An important outcome of the Probiotic Hypothesis would be development of resistance of the coral holobiont to diseases" (Reshef et al, 2006. Environmental microbiology 8 (12):2068 - 2073

coral product - any living or dead specimens, parts, or derivatives, or any product containing specimens, parts, or derivatives, of any species of coral in the cnidarian Orders: Antipatharia (black corals), Scleractinia (stony corals), Gorgonacea (horny corals), Stolonifera (organpipe corals and others), Alcyanacea (soft corals), and Coenothecalia (blue coral), of the Class Anthozoa; and all species of the Order Hydrocorallina (fire corals and hydrocorals) of the Class Hydrozoa

coral reef - a wave-resistant structure resulting from cementation processes and the skeletal construction of hermatypic corals, calcareous algae, and other calcium carbonate-secreting organisms

Coral Reef Alliance (CORAL) - CORAL promotes coral reef conservation around the world by working with the dive industry, governments, local communities and other organizations to protect and manage coral reefs, establish marine parks, fund conservation efforts, and raise public awareness with the mission to keep coral reefs alive for future generation

coral reef bleaching monitoring product - near real-time information derived from data either from satellite images or in situ monitoring stations at coral reef areas to help improve and sustain coral reef health throughout the world

Coral Reef Degradation in the Indian Ocean (CORDIO) - CORDIO is an international program created to respond to the degradation of coral reefs throughout the Indian Ocean. In the western Indian Ocean region coral reefs are key ecosystems that support large sectors of the countries' populations and economies, through artisanal fisheries, tourism and large-scale investments. Projects within CORDIO focus on determining a) the biophysical impacts of coral degradation as a result of bleaching and other disturbances, and the long term prospects for recovery, b) the socio-economic impacts of coral mortality and options for mitigating these through management and development of alternative livelihoods, and c) the prospects of restoration and rehabilitation of reefs to accelerate the ecological and economic recovery.

Image of a CREWS station

A CREWS station on site.


Coral Reef Early Warning System (CREWS) - in situ NOAA meteorological and oceanographic monitoring sites that collect data continuously which are transmitted hourly via satellite to a data archival site. An automated system (hardware and software) that monitors select oceanographic and meteorological parameters and produces specialized alerts when conditions may result in environmental stresses conducive of coral bleaching. NOAA plans to expand the CREWS from the Florida Keys/Bahamian sites to many remote coral reef sites throughout the world

Coral Reef Ecosystems Integrated Observing System (CREIOS) - The Coral Reef Ecosystem Integrated Observing System (CREIOS) will provide a diverse suite of long-term ecological and environmental observations and information products over a broad range of spatial and temporal scales. The CREIOS goal is to understand the condition and health of, and processes influencing, coral reef ecosystems, to assist stakeholders in making improved and timely ecosystem-based management decisions to conserve coral reefs

Coral Reef Virtual Laboratory (CoRViL) - a joint venture of the National Oceanic and Atmospheric Administration (NOAA), the Great Barrier Reef Marine Park Authority (GBRMPA), and the Australian Institute of Marine Science (AIMS). This venture will provide an automated, cooperative exchange of electronic data, computer processing power and remote sensing tools for the purpose of monitoring the coral reef environment on the Great Barrier Reef. It is anticipated that this effort will eventually provide a model for monitoring physical processes at other sensitive coral reef areas throughout the world

Coral Reef Watch (CRW) - formed in 2000, NOAA's CRW maximizes NESDIS's coral reef resources by joining and building on existing NESDIS coral reef strengths under a more coordinated program. It seeks to develop a long-term coral reef monitoring system with the ability to predict coral bleaching episodes in all major U.S. coral reef areas

Image of coral rock

Coral rock for sale in the marine aquarium trade. (Photo: Shell Horizons, Inc.)


coral rock - products used in the aquarium trade. Coral rock is consolidated material, greater than 3 cm in diameter, formed of fragments of dead coral and which may also contain cemented sand, coralline algae and other sedimentary rocks. 'Live rock' describes pieces of coral rock to which are attached live specimens of invertebrate species and coralline algae

Coral Stress Index - an index that indicates the relative accumulated thermal stress experienced by a given coral reef

Coral Triangle Support Partnership (CTSP) - in 2009, the World Wildlife Fund (WWF) and other partners supported the launch of the Coral Triangle Initiative (CTI), which included commitments by the governments of Indonesia, Malaysia, Papua New Guinea, the Philippines, the Solomon Islands, and Timor-Leste, to safeguard their marine resources and ensure income and food security for the millions of people who depend on those resources. In support of the CTI, the Coral Triangle Support Partnership (CTSP) was created with the goal of improving the management of biologically and economically important coastal and marine resources and associated terrestrial ecosystems that support the livelihoods of people's economies in the Coral Triangle. The CTSP is a five-year, $40 million project executed through a Cooperative Agreement with the United States Agency for International Development (USAID) to the WWF, which includes a consortium of the WWF, Conservation International (CI), and the Nature Conservancy (TNC).

Corallimorpharia - an order of the subclass Zoantharia (Hexacorallia) of the phylum Cnidaria. They are mostly solitary species (some are colonial) that resemble true corals, but lack a calcareous skeleton

Image of coralline algae

Coralline algae remove calcium from water. This calcium carbonate gives them a coral-like look. As they die, they turn white. (Photo: Nancy Sefton)


coralline algae - algae that form solid calcium carbonate accretions

Coralline Lethal Orange Disease (CLOD) - a disease which infects coralline algae

corallite - a coral cup; the skeleton of an individual polyp

corallite wall - a raised skeletal structure surrounding the corallite, separating it from its neighboring corallites on the surrounding colony surface

Image of parrotfish and coral

Parrotfish are often coralliverous, scraping the coral polyps with beaklike jaws.


corallivore - an organism that eats coral

corallum - a complete coral colony; a coral head

cordate - heart-shaped; in the form of two rounded lobes

core - a cylindrical sample, obtained with a hollow drill, extracted from, inter alia, a seabed, lake bottom, or coral to investigate the composition and depths of layers

core (geology) - the innermost layer of the Earth, consisting primarily of pure metals such as iron and nickel. The core is the most dense layer of the Earth, and is divided into the outer core, which is believed to be liquid, and the inner core, which is believed to be solid

COREMO 2 - a data entry and analysis program developed by the southern Indian Ocean Global Coral Reef Monitoring Program (GCRMN) node. It is based on ARMDES (AIMS Reef Monitoring Data Entry System) but has been extensively modified from COREMO to suit the needs of the GCRMN

Corexit - a trade name for a toxic mix of chemicals used to disperse spilled or oozing oil (a dispersant). It breaks up the oil, allowing it to decompose more quickly or evaporate before being washed to shore

cornetfish - any species of spiny-rayed fishes in the family Fistulariidae. Cornetfishes are elongated, depressed-bodied fishes with a greatly extended tubular snout, a very small mouth, and a long thin filament extending from the middle of the caudal fin. They are closely related to the trumpetfishes (Aulostomidae) which are more robust and lack the caudal filament. At present there are approximately five known species of cornetfishes

correlate - to show a relationship between entities

correlation - a relation between a variable and one or more related variables

correlation coefficient - a measure of the relationship between variables

correlogram - a graph illustrating the auto-correlations between members of a time series (vertical axis) for different separations in time (horizontal axis)

corridor - a connection between two segments of habitat that allows for the safe movement of individuals between the segments

corrugated - having a surface with alternating parallel ridges and grooves

cortex - the outer portion (layer) of an organ

corticocyte - a cell that produces gorgonin and forms the axis in a gorgonian

corymbose - describes coral colonies with horizontal interlocking branches and short upright branches

cosmid - a DNA vector that allows the insertion of long fragments of DNA (up to 50 kbases)

cosmopolitan - having a global distribution

cosmopolitan distribution - worldwide distribution within habitat limits

cost-benefit analysis - an assessment of the short-term and long-term costs (losses) and benefits (gains) that arise from an economic decision. If the calculated benefits exceed the calculated costs, the decision to buy an economic good or provide a public good is considered profitable

costa - the extension of the septa outside the calyx into the coenosteum

coulombmeter - an instrument for measuring electric charge

Image of Coulter counter

A Coulter counter is an instrument used to measure the distribution of particle size.


Coulter counter - an instrument that measures particle size distribution from the change in electrical conductivity as particles flow through a small opening

Image of a white shark

Counter shading in a white shark. The darker dorsal surface and lighter ventral surface allows the shark to blend in with the environment when viewed from above or below. (Photo: NOAA)


counter shading - protective body coloration where the dorsal surface (above) is dark and the ventral surface (below) is lighter

covalence - the number of pairs of electrons an atom can share with other atoms

covalent bond - a bond between two or more atoms that is provided by electrons that travel between the atoms' nuclei, holding them together but keeping them a stable distance apart

cove - a small sheltered indentation in the shoreline. A cove is smaller than a bay

CPCe - See: Coral Point Count with Excel extensions (CPCe)

craggy - a surface which is rocky and steep

craterform - massive shape with a broad base and a large, central depression

crateriform - cup-shaped

Craton - an old and stable part of the continental lithosphere, generally found in the interiors of tectonic plates. Cratons are composed of ancient basement rock which may be covered by younger sedimentary rock

creel survey - a survey of anglers in a particular area to discover the types and numbers of fish caught

crenulate - a shape in which the edge is slightly scalloped

Image of a squirrelfish

The large eyes of a squirrelfish hint about its crepuscular behavior, allowing it to be active and feed during periods of diminished light. (Photo: Copyright Corel Corporation)


crepuscular - most active at low light levels during dusk and dawn

criterion - a standard rule or test on which a judgment or decision can be based.

critical depth - the depth in seawater below which carbon loss through respiration by phytoplankton exceeds carbon gain through photosynthesis; no net phytoplankton production occurs

critical habitat - the ecosystem upon which endangered and threatened species depend; habitat crucial to the survival of the species

critical value - in statistics, the value of a test statistic at or beyond which the null hypothesis is rejected

crocodile - in addition to freshwater environments, crocodiles also inhabit brackish waters and coral reef habitats. The American crocodile can be found on offshore cayes and atolls, and in mainland coastal habitats. Two endangered species of crocodile, the American crocodile (Crocodylus acutus) and Morelet's crocodile (Crocodylus moreletii), occur in Belize. The largest American crocodile population (less than 300) in Belize is found in the Turneffe Atoll, which is one of the largest remaining nesting areas in the Caribbean. Morelet's crocodile can be found in brackish water around coastal areas. The saltwater crocodile (Crocodylus porosus), the world's largest reptile, can be found in coastal, coral reef-rich waters from eastern India and Bangladesh through Southeast Asia to Papua New Guinea and Australia. They occur as far east as the Solomon Islands and Vanuatu

crocodilefish - anyof about 60 species of bony fishes in the family Platycephalidae.. Crocodilefishes have distinct pits immediately behind the eyes and a concave head margin.Their eyes have iris lappets which help break up the black pupil and improve its camouflage. Cr

cross - in genetics, the mating of two individuals or populations

cross section - a section sliced at right angles to the longitudinal axis of the animal or structure examined; a transverse section

crossing over - in genetics, the breaking during meiosis of one maternal and one paternal chromosome, the exchange of corresponding sections of DNA, and the rejoining of the chromosomes. This process can result in an exchange of alleles between chromosomes

crust (geology) - the outermost layer of the Earth, consisting of relatively low-density rocks

Image of marine shrimp

A marine shrimp (Crustacea).


Crustacea - a subphylum of Arthropoda that includes shrimp, mantis shrimp, lobsters, crabs, water fleas, copepods, crayfish and wood lice. There are almost 40,000 described species of crustaceans. The Crustacea are mainly aquatic, but include some semi-terrestrial and terrestrial groups

crustose - grows flat along the substrate; crust-like

Image of coralline algae

Crustose coralline algae are very common on reefs. (Photo: http://www.botany.hawaii.edu)


crustose coralline algae - crustose coralline algae are red algae of the division Rhodophyta. They are very important members of a reef community in which they cement and bind the reef together. They are particularly common in high wave energy areas but can also be found throughout all reef zones. Crustose corallines resemble pink or purple pavement. Morphology can range from smooth and flat, to rough and knobby, or even leafy

cryophile - an organism that inhabits habitats with extremely cold temperatures ranging from -15°C - +10°C; also known as "Psychrophiles"

Cryophillic - refers to organisms that grow and reproduce at extremely low temperatures, typically below 10 degrees C

crypsis - protective camouflage coloration where the individual resembles its backgound

Image a viper moray

The viper moray is a cryptic fish, concealing itself in crevices and holes in the coral reef. (Photo: Dr. Anthony Picciolo)


cryptic - pertaining to concealment, usually in reference to color pattern or behavior (e.g., hiding in reef crevices)

cryptobiosis - a suspension of life processes when conditions become unfavorable. In these resistant states some animals, such nematodes, rotifers and tardigrades, as can survive extreme drying, heat, or cold, and then return to "life" when favorable conditions return

cryptogenic - of obscure or unknown origin

cryptogenic species - species whose endemic or alien status is unclear. For many species, data are lacking on their original geographic distribution, and it cannot be determined whether they are native or introduced into a particular location

Image of ctenophore

Light refracts off the ctenes of the comb-jelly Mertensia ovum producing stripes of rainbow color. (Photo: Kevin Raskoff, MBARI.)


ctene - the locomotor structure of ctenophores (comb jellies) made up of cilia arranged into flattened plates. The ctenes are arranged into eight longidutinal bands, from the aboral to the oral surface

ctenidium - a comb-like structure; the respiratory organ of a mollusk (ctenidial gill)

cteniform - comb-shaped

Image of a ctenoid scale

A ctenoid scale of a bony fish. It is thought that the combed edge helps to reduce hydrodynamic drag during swimming. (Photo: Rick Gillis, Ph.D., Biology Dept., University of Wisconsin-La Crosse)


ctenoid - comb-shaped; with a comb-like margin

ctenophore - a member of the animal phylum Ctenophora. A small phylum (about 50 species) whose members, known as comb jellies and sea walnuts, superficially resemble jelly fishes. These planktonic organisms are thought to have evolved from a medusoid cnidarian

cue - in animal behavior, a signal fom one animal which acts as a stimulus to elicit a behavioral response in another. The cue may be visual, acoustic, or chemical

culling - the selective removal of animals from a population for conservation purposes

culture - a population of plant or animal cells or microorganisms that is grown under controlled conditions

culture medium - a substance which contains nutrients and a favorable environment for the in vitro growth of microorganisms and cells

cuneiform - wedge-shaped

curvilinear relationship - a situation that is best represented by something other than a straight line

cusp - a point or projection on a tooth

cutaneous - pertaining to the skin

cuticle - an extracellular, protective external body covering, secreted by the epidermis, of some invertebrate animals, usually composed of fibrous material, such as chitin or collagen; the waxy layer of epidermal cells of plant parts, such as leaves, stems, and fruit

Cuvierian tubules - clusters of sticky tubules, located at the base of the respiratory tree, which may be discharged by some sea cucumbers (holothurians) when mechanically stimulate, as for example, when being threatened by a predator. Their great adhesivity, combined with their high tensile strength, allows the Cuvierian tubules to entangle and immobilize potential predators with which they come into contact. After expulsion, the lost tubules are readily regenerated, making them a formidable defense mechanism

cyanide fishing - a destructive fishing technique in which sodium cyanide or some other cyanide compound is used to stun and capture coral reef fishes for the aquarium and live food trade

cyano- - a prefix denoting blue or dark blue

Image of Cyanobacteria bloom

A bloom caused by cyanobacteria (-blue-green algae+).


cyanobacteria - photosynthetic aquatic bacteria, often called blue-green algae, but have no relationship to algae. Cyanobacteria get their name from the bluish pigment phycocyanin, which they use to capture light for photosynthesis. They also contain chlorophyll a, the same photosynthetic pigment found in the chloroplasts of plants. Not all "blue-green" bacteria are blue; some common forms are red or pink, resulting from the pigment phycoerythrin

cyanotoxin - a toxin produced by cyanobacteria that has been implicated in human and animal illness and death. Cyanotoxins can accumulate in animals such as fishes and shellfish, and cause illnesses such as shellfish poisoning

cybernetics - an interdisciplinary field of science concerned with processes of communication and control in biological and artificial systems; the design or discovery and application of principles of regulation and communication

cyberspace - the whole range of information resources available through computer networks

cycloid - having a smooth-edged margin

cyclomorphosis - cyclical changes in form such as seasonal changes in morphology, as seen in some planktoic crustaceans

cyclone - an area of low pressure. Circulation is counterclockwise around a low pressure system in the Northern Hemisphere and clockwise in the Southern Hemisphere

cyclonic - refers to a region of low atmospheric sea level pressure; or, the wind system around such a low pressure center that has a clockwise rotation in the Northern Hemisphere and a counterclockwise rotation in the Southern Hemisphere

cyclosystem - a system of very small tubules that links the polyps of calcareous colonial hydrozoans

cydippid larva - a larva of ctenophores

cystid - the exoskeleton and body wall of the stationary trunk of bryozoans

cytochrome oxidase - an oxidizing enzyme found in mitochondria of cells. It contains iron and a porphyrin and is important in cellular respiration as an agent of electron transfer from certain cytochrome molecules to oxygen molecules. Cytochrome c is a highly conserved protein found in plants, animals, and many unicellular organisms. This, along with its small size, makes it useful in studies of evolutionary divergence

cytogenetics - the science that links the study of inheritance (genetics) with that of cells (cytology) and is concerned mainly with the study of the structure, and function of chromosomes

cytokinesis - the division of the cytoplasm of a cell during cell division

cytology - the study of the structure and function of cells

cytometer - an instrument for counting cells

cytoplasm - the protoplasm of a cell exclusive of that of the nucleus. It consists of a continuous aqueous solution (cytosol) and the organelles and inclusions suspended in it. The cytoplasm is the site of most of the chemical activities of the cell

cytoplasmic genes - DNA-containing bodies in the cell but external to the nucleus

cytoplasmic inheritance - inheritance via genes found in cytoplasmic organelles, e.g., mitochondria, rather than the nuclear genes; inheritance via the maternal lineage; extrachromosomal inheritance

Diagram of cytosine

Diagram of the chemical structure of cytosine, one of the four nitrogenous bases in DNA.


cytosine - one of the four nitrogenous bases in DNA that make up the letters ATGC. Cytosine is the "C". The others are adenine, guanine, and thymine. Cytosine always pairs with guanine

cytoskeleton - the network of microtubules, microfilaments, and larger filaments that provides a eukaryotic cell with its structural support, shape, and its capacity to move and arrange its organelles within the cell

cytosol - the fluid, less structured part of the cytoplasm of a cell, excluding organelles and membranous structures; the portion of the cytoplasm which remains after removal of particulate components

cytotoxic - able to cause cell death; causing damage to cell structure or function

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