Science / Marine Biology Glossary

Pteropods: Group of holoplanktonic gastropods

Pycnocline: Depth zone within which sea-water density changes maximally

Q10: Increase of metabolic rate with an increase of 10ºc

Quadrat: An ecological sampling unit that consists of a square frame of known area. The quadrat is used for quantifying the number or percent cover of a given species within a given area. See also transect.

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

R: The intrinsic rate of increase of a population

Radiocarbon Technique: The estimation of primary productivity by the measurement of radiocarbon uptake

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 . . . View Full Definition

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 replenished through natural processes within a human life span, if it is soundly managed. Compare nonrenewable resource.

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. See Accuracy and Precision.

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