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

Nitrogen fixation
The conversion of gaseous nitrogen to nitrate by specialized bacteria.

No-take Reserves
Geographic areas where by law no one is allowed to fish or collect biological specimens. Rules could apply to one or all species.

Nuisance bloom
A rapid increase of one or only a few species of phytoplankton, resulting in densities high enough to cause discoloration of the surface water, possible increase of toxins, and degradation of water quality aspects such as dissolved oxygen

Nutrient cycling
The pattern of transfer of nutrients between the components of a food web

Oceanic
Associated with sea-water environments seaward of the shelf-slope break

Oceanic ridge
A sinuous ridge rising from the deep-sea floor

Oligotrophic
Refers to water bodies or habitats with low concentrations of nutrients

Omnivory
Being able to feed in more than one distinct way (e.g., an organism capable of carnivory and herbivory)

Optimal foraging theory
A theory designed to predict the foraging behavior that maximizes food intake per unit time

Organic
Deriving from living organisms

Organic nutrients
Nutrients in the form of molecules synthesized by or originating from other organisms

Osmoconformer
An organism whose body fluids change directly with a change in the concentrations of dissolved ions in the external medium

Osmoregulator
An organism that regulates the concentration of dissolved ions in its body fluids irrespective of changes in the external medium

Osmosis
The movement of pure water across a membrane from a compartment with relatively low dissolved ions to a compartment with higher concentrations of dissolved ions

Outwelling
The outflow of nutrients from an estuary or salt-marsh system to shelf waters

Overdominance
Selection favoring heterozygotes

Oxygen dissociation curve
A curve showing the percent saturation of a blood pigment, such as hemoglobin, as a function of oxygen concentration of the fluid

Oxygen minimum layer
A depth zone, usually below the thermocline, in which dissolved oxygen is minimal

Parapatric speciation
The differentiation into distinct species of populations experiencing some gene flow

Parasite
An organism living on or in, and negatively affecting, another organism

Particulate organic matter
Particulate material in the sea derived from the decomposition of the nonmineral constituents of living organisms

Patchiness
A condition in which organisms occur in aggregations

Pelagic
Living in the water column seaward of the shelf-slope break

Pellets
Compacted aggregations of particles resulting either from egestion (fecal pellets) or from burrow-constructing activities of marine organisms

Penetration anchor
In hydraulically burrowing organisms, any device used to penetrate and gain an initial purchase on the sediment so that the body can be thrust in farther

Peptides
Chains of amino acids; often portions of a protein molecule

pH
Measure of he acidity or basicity of water (-log10 of the activity of hydrogen ions in water)

Phenotypic plasticity
The capacity of an individual to produce different phenotypes under different conditions. Non-genetic potential variability within the range of a single individual.

Phi scale
Scale used for measuring the grain size of sediments. = -log2 (grain diameter)

Photic zone
The depth zone in the ocean extending from the surface to that depth permitting photosynthesis

Photorespiration
Enhanced respiration of plants in the light relative to dark respiration

Photosynthate
A substance synthesized in the process of photosynthesis

Photosynthetic quotient
In photosynthesis, the moles of oxygen produced, divided by the moles of carbon dioxide assimilated

Photosynthetic rate
The rate of conversion of dissolved carbon dioxide and bicarbonate ion to photosynthetic product

Phototactic
Moving in response to light

Physiological race
A geographically defined population of a species that is physiologically distinct from other populations

Phytoplankton
The photosynthesizing organisms residing in the plankton

Planktivorous
Feeding on planktonic organisms

Plankton
Organisms living suspended in the water column and incapable of moving against water currents

Planktotrophic larva
Planktonic-dispersing larva that derives its nourishment by feeding in the plankton

Planula
The planktonic larval form produced by scleractinian corals and coelenterates

Plate
Major section of the earth's crust, bounded by such features as mid-ocean ridges

Pleistocene
Period of time, going back to approximately 2 million years before the present, in which alternating periods of glaciation and deglaciation have dominated the earth's climate

Pleuston
Refers to plankton that have a float protruding above the sea surface, such as the Portugese man-of-war.

Poikilotherm
An organism whose body temperature is identical to that of the external environment

Polyp
An individual of a solitary coelenterate or one member of a coelenterate colony

Polyphyletic
Refers to a group of species that do not have one common ancestor species

Population density
Number of individuals per unit area or volume

Porifera
The phylum comprising the sponges.

PPT
A measure of the salt content of sea water in terms of kg salt per kg of water, reckoned in parts per thousand. A conductivity version of this measure is the PSU, which differs from PPT by very little, on the order of 0.02 PSU or less.

Practical Salinity
See PSU

Precision
Precision is the repeatability of a measurement.

Predation
The consumption of one organism by another

Predator
An organism that consumes another living organism (carnivores and herbivores are both predators by this definition)

Primary producer
An organism capable of using the energy derived from light or a chemical substance in order to manufacture energy-rich organic compounds

Primary production
The production of living matter by photosynthesizing organisms or by chemosynthesizing organisms. Usually expressed as grams of carbon per square meter per year

Protein polymorphism
Presence of several variants of a protein of a given type (e.g., a certain enzyme, such as carboxylase) in a population

Province
A geographically defined area with a characteristic set of species or characteristic percentage representation by given species

Pseudofeces
Material rejected by suspension feeders or deposit feeders as potential food before entering the gut

PSU Practical Salinity Units
A measure of the salt content of seawater (practical salinity), based upon electrical conductivity of a sample relative to a reference standard of sea water, which now happens to be a reference set of diluted sea water samples from the North Atlantic of known salt content

Pteropods
Group of holoplanktonic gastropods

Pycnocline
Depth zone within which sea-water density changes maximally

Quantitative genetics
The study of the genetic basis of traits, usually explained in terms of the interaction of a group of genes with the environment

Radiolaria
Protistan phylum, whose members are planktonic and secrete an often elaborate siliceous test

Radula
A belt of teeth, found in gastropods and chitons. Used for feeding.

Random spatial distribution
Situation in which individuals are randomly distributed in a space; probability of an individual's being located at any given point is the same irrespective of location in the space

Recruitment
The residue of those larvae that have: (1) dispersed; (2) settled at the adult site; (3) made some final movements toward the adult habitat; (4) metamorphosed successfully, and (5) survived to be detected by the observer

Red tide
A dense outburst of phytoplankton (usually dinoflagellates) often coloring water red brown

Redox-potential discontinuity
That depth below the sediment-water interface marking the transition from chemically oxidative to reducing processes

Refuge
A device by which an individual can avoid predation

Regulator
An organism that can maintain constant some aspect of its physiology (e.g., body temperature) constant despite different and changing properties of the external environment

Renewable resource
A resource that can be regenerated (e.g., a growing diatom population that is being exploited by a copepod)

Reproductive effort
The fraction of assimilated nutrients that are devoted to reproductive behavior and gamete production

Resolution
The smallest amount of change that an instrument can discriminate.

Resource
A commodity that is required by an organism and is potentially in short supply

Respiration
Consumption of oxygen in the process of aerobic metabolism

Respiratory pigment
A molecule, polymer, or other complex adapted to bind and transport oxygen efficiently, usually in a circulatory system (e.g., hemoglobin)

Respiratory quotient
The ratio of moles of carbon dioxide produced to oxygen consumed in respiration

Rete mirabile
A countercurrent exchange structure of capillaries that allows gas uptake in a fish swim bladder

Reverse Bohr effect
Effect that occurs when lactate builds up in the blood of certain invertebrates and pH decreases, increasing the affinity of hemocyanin for oxygen

Reynolds number
A number that represents the relative importance of viscous forces and inertial forces in a fluid as Re increases, inertial forces become more important. n sea water, Re increaseswith increasing water velocity and with the size of the object in the water

Rip current
A concentrated rapid current moving offshore from a beach fronting a longshore current

Rise
Bottom of low relief at the base of the continental slope

ROV
Abbreviation for remotely operated vehicle, usually a submersible tethered to a ship, with facilities for video, remote sampling by grabbing arms, and precise navigation

Salinity
Number of kg of dissolved salts in one kg g of seawater, measured in parts per thousand. Actually this definition stands alongside another definition based upon water standards whose electrical conductivities are measured.

Salps
A group of pelagic tunicates (phylum Urochordata), either colonial or solitary, with buccal and atrial siphons on opposite sides of the body

Salt marsh
A coastal habitat consisting of salt-resistant plants residing in an organic-rich sediment accreting toward sea level

Scavenger
An organism that feeds on dead or decomposing animals or macrophytes

Scleractinia
Order of coelenterates, usually producing calcareous skeletons with hexameral symmetry

Scope for growth
The surplus of energy available for growth beyond that required for maintenance

Scyphozoa
the true jellyfish, members of the phylum Cnidaria

Sea-floor spreading
The horizontal movement of oceanic crust

Seasonal estuary
An estuary in which salinity at any one geographic point changes seasonally (e.g., decreases during the spring melt)

Seaward
Side of an island that faces the direction of wave action generated either by winds or by currents generated by more indirect forces

Secondary production
The production of living material per unit area (or volume) per unit time by herbivores. Usually expressed as grams carbon per meter square per year

Selection
A change in allele frequency over time in a population

Sequential hermaphrodite
An individual that sequentially produces male and then female gametes or vice versa

Sessile
Immobile because of an attachment to a substratum

Seston
Particulate matter suspended in seawater

Setules
Chitinous projections from copepod maxillipeds that trap food particles