Glossary of Marine Biology


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Calcareous Made of calcium carbonate


Carrying capacity. The total number of individuals of a population that a given environment can sustain


Carnivore An organism that captures and consumes animals


Catadromous fish.. Fish that spawns in seawater but feed and spends most of its life in estuarine or fresh water


Chaetognaths. See Arrowworms


Character displacement. A pattern in which two species with overlapping ecological requirements differ more when they co-occur than when they do not. The difference is usually in a morphological feature related to resource exploitation, as in the case of head size, which may be related to prey size


Chemosynthesis. Primary production of organic matter, using various substances instead of light as an energy source; confined to a few groups of microorganisms


Chlorinity. Grams of chloride ions per 1000 grams of seawater


Chloroplast. In eukaryotic organisms, the cellular organelle in which photosynthesis takes place


Cladogram. A tree-like diagram showing evolutionary relationships. Any two branch tips sharing the same immediate node are most closely related. All taxa that can be traced directly to one node (that is they are "upstream of a node") are said to be members of a monophyletic group.


Coastal reef. A coral reef occurring near and parallel to a coastline


Comb jellies. Members of the phylum Ctenophora, a group of gelatinous forms feeding on smaller zooplankton


Commensal. Having benefit for one member of a two-species association but neither positive nor negative effect on the other


Compensation depth. The depth of the compensation light intensity


Compensation light intensity. That light intensity at which oxygen evolved from a photosynthesizing organism equals that consumed in its respiration


Competition. An interaction between or among two or more individuals or species in which exploitation of resources by one affects any others negatively


Complex life cycle. A life cycle that consists of several distinct stages (e.g., larva and adult)


Conformer. An organism whose physiological state (e.g., body temperature) is identical to, and varies identically with, that of the external environment


Continental drift. Horizontal movement of continents located in plates moving via sea-floor spreading


Continental shelf. A broad expanse of ocean bottom sloping gently and seaward from the shoreline to the shelf-slope break at a depth of 100 to 200 m


Continental slope. See Slope


Convergence. The contact at the sea surface between two water masses converging, one plunging below the other


Copepod. Order of crustaceans found often in the plankton


Coprophagy. Feeding on fecal material


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


Corer. Tubular benthic sampling device that is plunged into the bottom in order to obtain a vertically oriented cylindrical sample


Coriolis effect. The deflection of air or water bodies, relative to the solid earth beneath, as a result of the earth's eastward rotation


Countercurrent exchange mechanism. Mechanism by which two vessels are set side by side, with fluid flowing in opposite directions, allowing efficient uptake and retention of heat, oxygen, or gas, depending upon the type of exchanger


Countershading. Condition of organisms in the water column that are dark-colored on top but light-colored on the bottom


Counter-illumination. Having bioluminescent organs that are concentrated on the ventral surface so as to increase the effect of countershading (see also countershading)


Critical depth. That depth above which total integrated photosynthetic rate equals total integrated respiration of photosynthesizers


Critical salinity. A salinity of approximately 5 to 8% that marks a minimum of species richness in an estuarine system


Ctenophora. See Comb jellies