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Number of Results: 103

C (carbon)

C.O.D.

calcium carbonate

cannibalism

carbohydrate

carbon compensation depth (CCD)

carbon cycle

carbon dioxide

carnivorous

carrier

carrying capacity

cartilagenous fish

catabolism

catadromous

catalyst

chart datum

chelation

chemical oxygen demand (COD)

chemoreceptor

chemotaxis

chi-squared test

china clay

chitin

chlorination

chlorinity

chlorophyll

chromomere

chromosome

chronic

ciliates

circadian rhythm

circalittoral zone

clay(clay soil)

climax

clone

cluster analysis

coal

coarse-grained species

coastal dynamic processes

coastal zone management

cobble

coefficient of ecological efficiency

coefficient of permeability

coefficient of variation

coefficient of viscosity

coelenterates

coexistence

cohort

cold resistance

colliery waste

commensalism

commensals

communal

community

compensation depth

compensation light intensity

competition

competitive association

competitive exclusion

competitive release

concentration response curve

concentrations

condition factor

conductivity

conservation

conservation area

conservative wastes

conspecific

consumer

contamination

continental drift

continental island

continental margin

continental rise

continental shelf

continental slope

continuity

convergence

conversion efficiency

cooling water

copepods

coprophagus

coralline

corals

correlation

cosmopolitan species

cost-benefit analysis

cotidal line

courtship

courtship ritual

covariance

critical depth

critical thermal maximum (CTM)

critical velocity

crossover value (COV)

crude oil

crustaceans

cultivation

culture

current

cyanobacteria

cyst

cytogenetics

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euphotic zone

Definition

For the purpose of biological investigations, it is convenient to consider the sea as divided vertically into three zones with respect to the amount of light that is present. These are: (a) the euphotic zone, which is abundantly supplied with light sufficient for the photosynthetic processes of plants (in oceans down to 80 m); (b) the disphotic zone, which is only dimly lighted and extends in the open ocean from about 80 m to 200 or more metres. No effective plant production can take place here; (c) the aphotic zone, the lightless region below the disphotic zone. The depth of the euphotic zone varies with the water's extinction coefficient, the angle of incidence of the sunlight, the length of day and cloudiness.

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