Copy of `Marine Biology Glossary`

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Marine Biology Glossary Category: Animals and Nature > Marine Biology Date & country: 13/09/2007, USA Words: 362

Abyssal plain
The deep ocean floor, an expanse of low relief at depths of 4,000 to 6,000 m

Abyssopelagic zone
The 4,000 to 6000-m-depth zone, seaward of the shelf-slope break

Acclimation
Given a change of a single parameter, a readjustment of the physiology of an organism, reaching a new steady state

Accuracy
Is the correctness of a measure when comparing to a known standard

Age structure
The relative abundance of different age classes in a population

Aggregated spatial distribution
A case where individuals in a space occur in clusters too dense to be explained by chance

Ahermatypic
Non-reef-building (referring to scleractinian corals)

Allele
One of several variants that can occupy a locus on a chromosome

Allopatric speciation
The differentiation of geographically isolated populations into distinct species

Allozyme
A variant of an enzyme type. These may be variants of a specific enzyme (e.g., cytochrome c) that are the products of a single genetic locus.

Amensal
Negatively affecting one or several species

Amino acids
Basic structural unit of proteins

Anadromous fish
Fish that spends most of its life feeding in the open ocean but that migrates to spawn in fresh water

Anoxic
Lacking oxygen.

Arrow worms
Members of the phylum Chaetognatha, a group of planktonic carnivores

Asexual reproduction
Reproduction of the individual without the production of gametes and zygotes

Assimilation efficiency
The fraction of ingested food that is absorbed and used in metabolism

Assortative mating
The mating of a given genotype mates with another genotype at a frequency disproportionate to that expected from random encounter

Atoll
A horseshoe or circular array of islands, capping a coral reef system perched around an oceanic volcanic seamount

Attenuation (of light)
Diminution of light intensity; explained, in the ocean, in terms of absorption and scattering

Autotrophic algae
Algae capable of photosynthesis and growth using only dissolved inorganic nutrients

Auxotrophic algae
Algae requiring a few organically derived substances, such as vitamins, along with dissolved inorganic nutrients for photosynthesis

Bathypelagic zone
The 2,000 to 4,000-m-depth zone seaward of the shelf-slope break

Benthic-pelagic coupling
The cycling of nutrients between the bottom sediments and overyling water column

Benthos
Organisms that live associated with the sea bottom. Examples include burrowing clams, sea grasses, sea urchins, acorn barnacles.

Berm
A broad area of low relief in the upper part of a beach

Between-habitat comparison
A contrast of diversity in two localities of differing habitat type (e.g., sand versus mud bottoms)

Biodiversity
See species richness

Biogenic graded bedding
A regular change of sediment median grain size with depth below the sediment-water interface caused by the activities of burrowing organisms

Biogenically reworked zone
The depth zone, within a sediment, that is actively burrowed by benthic organisms

Bioluminescence
Light emission, often as flashes, by many marine organisms

Biomass
See Standing crop

Blood pigment
A molecule used by an organism to transport oxygen efficiently, usually in a circulatory system (e.g., hemoglobin)

Bloom
(phytoplankton) A population burst of phytoplankton that remains within a defined part of the water column

Bohr effect
When blood pH decreases, the ability of hemoglobin to bind to oxygen decreases. An adaptation to release oxygen in the oxygen starved tissues in capillaries where respiratory carbon dioxide lowers blood pH

Boreal
Pertaining to the Northern Hemisphere, north temperate zone

Boring
Capable of penetrating a solid substratum by scraping or chemical dissolution

Bottom-up control
Refers to food webs. A control of a population that comes from change lower in a food web (e.g., control of a population of mussels by abundance of phytoplankton food).

Boundary layer
A layer of fluid near a surface, where flow is affected by viscous properties of the fluid. At the surface, fluid velocity must be zero, and the boundary layer is a thin film that depends on surface texture, fluid velocity in the 'mainstream of flow,' and fluid mass properties such as salinity.

Brackish sea
Semienclosed water body of large extent in which tidal stirring and seaward flow of freshwater do not exert enough of a mixing effect to prevent the body of water from having its own internal circulation pattern

Browsers
Organisms that feed by scraping thin layers of living organisms from the surface of the substratum (eg., periwinkles feeding on rock-surface diatom films; urchins scraping a thin, filmy sponge colony from a rock)

Calcareous
Made of calcium carbonate

Carnivore
An organism that captures and consumes animals

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

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 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

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

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

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

Daily estuary
An estuary in which tidal movements cause substantial changes in salinity at any one location on a daily basis

Deep layer
The layer extending from the lowest part of the thermocline to the bottom

Deep-scattering layer
Well-defined horizon in the ocean that reflects sonar; indicates a layer usually consisting of fishes, squid, or other larger zooplankton

Demographic
Referring to numerical characteristics of a population (e.g., population size, age structure)

Density
(seawater) Grams of sea water per milliliter of fluid

Density-dependent factors
Factors, such as resource availability, that vary with population density

Deposit feeder
An organism that derives its nutrition by consuming some fraction of a soft sediment

Detritus
Particulate material that enters into a marine or aquatic system. If derived from decaying organic matter it is organic detritus.

Diatom
Dominant planktonic algal form with siliceous test, occurring as a single cell or as a chain of cells

Diffusion
The net movement of units of a substance from areas of higher concentration to areas of lower concentration of that substance

Digestion efficiency
The fraction of living food that does not survive passage through a predator's gut

Dinoflagellate
Dominant planktonic algal form, occurring as a single cell, often biflagellate

Directional selection
Preferential change in a population, favoring the increase in frequency of one allele over another

Dissolved organic matter
Dissolved molecules derived from degradation of dead organisms or excretion of molecules synthesized by organisms

Disturbance
A rapid change in an environment that greatly alters a previously persistent biological community

Diversity
A parameter describing, in combination, the species richness and evenness of a collection of species. Diversity is often used as a synonym for species richness

Diversity gradient
A regular change in diversity correlated with a geographic space or gradient of some environmental factor

Ekman circulation
Movement of surface water at an angle from the wind, as a result of the Coriolis effect

Emigration
The departure of individuals from a given area

Endosymbiotic
Being symbiotic and living within the body of an individual of the associated species

Environmental stress
Variously defined as (a) an environmental change to which an organism cannot acclimate and (b) an environmental change that increases the probability of death

Epibenthic (epifaunal or epifloral)
Living on the surface of the bottom

Epidemic spawning
Simultaneous shedding of gametes by a large number of individuals

Epipelagic zone
The 0- to 150-m-depth zone, seaward of the shelf-slope break

Epiphyte
Microalgal organism living on a surface (e.g., on a seaweed frond)

Estuarine flow
Seaward flow of low-salinity surface water over a deeper and higher -alinity layer

Estuarine realms
Large coastal water regions that have geographic continuity,are bounded landward by a stretch of coastline with fresh-water input, and are bounded seaward by a salinity front