This glossary defines words, terms & phrases you may have heard but don’t quite understand. This glossary 
includes terminology used in coastal science, engineering, geology, marine biology, management, oceanography as well as the technologies that characterize, measure, describe or quantify the physical properties, processes and changes of coastal & ocean zones.
Abyssal Plain
The deep ocean floor, an expanse of low relief at depths of 4,000 to 6,000 meters
Abyssopelagic Zone
The 4,000 to 6,000 meter 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 Specification
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 their life feeding in the open ocean but that migrates to spawn in freshwater
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
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 meter depth zone seaward of the shelf-slope break
Benthic-pelagic Coupling
The cycling of nutrients between the bottom sediments and overlying 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
Biogenically Reworked Zone
The depth zone within a sediment, that is actively burrowed by benthic organisms
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
Bioluminescence
Light emission often as flashes, by many marine organisms
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 and 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
Brackish Sea
Semi-enclosed 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; sea urchins scraping a thin, filmy sponge colony from a rock)
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 & consumes animals
Catadromous Fish
Fish that spawns in saltwater but feed and spends most of its life in estuarine or freshwater
Character Displacement
A pattern in which 2 species with overlapping ecological requirements differ more when they co-occur than when they do not
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 1,000 grams of seawater
Chloroplast
In eukaryotic organisms, the cellular organelle in which photosynthesis takes place
Cladogram
A tree-like diagram showing evolutionary relationships
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 meters
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-Current 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 ex-changer
Counter-Shading
Condition of organisms in the water column that are dark-colored on top but light-colored on the bottom
Counter-Illumination
Having bio-luminescent organs that are concentrated on the ventral surface so as to increase the effect of counter-shading
Critical Depth
That depth above which total integrated photosynthetic rate equals total integrated respiration of photo-synthesizers
Critical Salinity
A salinity of approximately 5% to 8% that marks a minimum of species richness in an estuarine system
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
Grams of seawater 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
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 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
El Niño-Southern Oscillation
Condition in which warm surface water moves into the eastern Pacific, collapsing up-welling and increasing surface-water temperatures and precipitation along the west coast of North & South America
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 1 to 150 meter 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-salinity 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
Estuary
A semi-enclosed body of water that has a free connection with the open sea and within which seawater is diluted measurably with freshwater that is derived from land drainage
Euphausiid
Member of an order of holoplanktonic crustacea
Eutrophic
Water bodies or habitats having high concentrations of nutrients
Evenness
The component of diversity accounting for the degree to which all species are equal in abundance, as opposed to strong dominance by one or a few species
Fecal Coliform Bacteria
Technically, all the facultative anaerobic gram negative non-spore forming rod shaped bacteria that fermet lactose in EC medium with gas production within 24h at 44.5 degrees °C
Fecundity
The number of eggs produced per female per unit time (often: per spawning season)
Foliose Coral
A coral whose skeletal form approximates that of a broad, flattened plate
Food Chain
An abstraction describing the network of feeding relationships in a community as a series of links of trophic levels, such as primary producers, herbivores and primary carnivores
Food Chain Efficiency
Amount of energy of some other quantity extracted from a trophic level, divided by the amount of energy produced by the next-lower trophic level
Food Web
A network describing the feeding interactions of the species in an area
Foraminifera
Protozoan group, individuals of which usually secrete a calcareous test; both planktonic and benthic representatives
Founder Principle
A small colonizing population is genetically unrepresentative of the source of population
Freshet
An increase of water flow into an estuary during the late winter or spring, owing to increased precipitation and snow melt in the watershed
Front
A major discontinuity separating ocean currents and water masses in any combination
Fugitive Species
A species adapted to colonize newly disturbed habitats
Gametophyte
Haploid stage in the life cycle of a plant
Generation Time
The time period from birth to average age of reproduction
Genetic Drift
Changes in allele frequencies that can be ascribed to random effects
Genetic Locus
A location on a chromosome (possibly of a diploid organism with variants that segregate according to the rules of Mendelian heredity)
Genetic Polymorphism
Presence of several genetically controlled variants in a population
Genotype
The genetic makeup of an organism with respect to a given genetic locus, the alleles it carries
Genus
The level of the taxonomic hierarchy above the species but below the family level
Geostrophic Flow
Movement of water in the oceans as a combined response to the Coriolis effect and gravitational forces created by an uneven sea surface
Geotactic
Moving in response to the earth’s gravitational field
Geographic Information System
A system that allows automatic location of information suitable for mapping and usually involves a software system that takes geographic position data and other data (e.g., type of bottom sediment) in order to create a map
Global Warming
Predicted increase in the earth’s oceanic and atmospheric temperature, owing to additions of carbon dioxide to the atmosphere, as a result of human activities
Global Positioning System
An electronic device that uses positioning signals from satellites in order to locate precisely latitude and longitude
Grab
Benthic sampling device with two or more curved metal plates designed to converge when the sampler hits bottom and grab a specified volume of bottom sediment
Grazer
A predator that consumes organisms far smaller than itself (e.g., copepods graze on diatoms)
Greenhouse Effect
Carbon dioxide traps solar-derived heat in the atmosphere near the earth
Gregarious Settling
Settlement of larvae that have been attracted to members of their own species
Gross Primary Productivity
The total primary production, not counting the loss in respiration
Guild
A group of species, possibly unrelated taxonomically, that exploit overlapping resources
Gyre
Major cyclonic surface current systems in the oceans
Halocline
Depth zone within which salinity changes maximally
Hardy-Weinberg Law
Law that states that the frequencies of genotypes in a population at a locus are determined by random mating and allele frequency
Herbivore
An organism that consumes plants
Harmful Algal Bloom
A bloom of (usually) planktonic micro-algae belonging to a strain of a species that has a toxic harmful to marine organisms or humans consuming marine organisms
Heritable Character
A morphological character whose given state can be explained partially in terms of the genotype of the individual
Hermaphrodite
An individual capable of producing both eggs and sperm during its lifetime
Hermatypic
Reef-building
Heterotrophic Algae
Algae that take up organic molecules as a primary source of nutrition
Heterozygote
With respect to a given genetic locus, a diploid individual carrying two different alleles
Highly Stratified Estuary
An estuary having a distinct surface layer of fresh or very-low-salinity water, capping a deeper layer of higher salinity, more oceanic water
Histogram
A multiple-bar diagram representing the frequency distribution of a group as a function of some variable
Holoplankton
Organisms spending all their life in the water column and not on or in the sea bed
Homeotherm
An organism that regulates its body temperature despite changes in the external environmental temperature
Homozygote
With respect to a given genetic locus, a diploid individual carrying 2 identical alleles
Hydrographic
Referring to the arrangement and movement of bodies of water, such as currents and water masses
Hydrothermal Vents
Sites in the deep ocean floor where hot, sulfur-rich water is released from geothermally heated rock
Hypothesis
A refutable statement about one or a series of phenomena
Infaunal
Living within a soft sediment and being large enough to displace sedimentary grains
Inter-specific Competition
Condition in which one species’ exploitation of a limiting resource negatively affects another species
Interstitial
Living in the pore spaces among sedimentary grains in a soft sediment
Isotonic
Having the same overall concentration of dissolved substances as a given reference solution
Keystone Species
A predator at the top of a food web, or discrete sub-web, capable of consuming organisms of more than one trophic level beneath it
La Niña
Is the coupled ocean-atmosphere phenomenon that is the counterpart of El Niño as part of the broader El Niño–Southern Oscillation climate pattern
Laminar Flow
The movement of a fluid where movement of the entire fluid is regular and with parallel streamlines
Larva
A discrete stage in many species, beginning with zygote formation and ending with metamorphosis
Larvacea
A group of planktonic tunicates that secrete a gelatinous house, used to strain unsuitable particles (large particles are rejected) with an inner filter apparatus of the house, the so-called food trap or particle-collecting apparatus, is used to retain food particles
LD50
The value of a given experimental variable required to cause 50% mortality
Leaching
The loss of soluble material from decaying organisms
Lecithotrophic Larva
A planktonic-dispersing larva that lives off yolk supplied via the egg
Leeward
The side of an island opposite from the one facing a persistent wind
Life Table
A table summarizing statistics of a population, such as survival and reproduction, all broken down according to age classes
Litter
Accumulations of dead leaves in various states of fragmentation and decomposition
Logistic Population Growth
Population growth that is modulated by the population size relative to carrying capacity
Long-Shore Current
A current moving parallel to a shoreline
Macrobenthos
Benthic organisms (animals or plants) whose shortest dimension is greater than or equal to 0.5 millimeters
Macrofauna
Animals whose shortest dimension is greater than or equal to 0.5 millimeters
Macrophyte
An individual alga large enough to be seen easily with the unaided eye
Macroplankton
Planktonic organisms that are 200-2,000 micrometers in size
Mainstream Flow
The flow in a part of the fluid (e.g., in a tidal creek) that is well above the bottom or well away from a surface and essentially not under the influence of the boundary layer
Mangrove Forest
A shoreline ecosystem dominated by mangrove trees, with associated mud flats
Marine Snow
Fragile organic aggregates, resulting from the collision of dissolved organic molecules or from the degradation of gelatinous substances such as larvacean houses
Marine Protected Area
A conservation geographic unit designed to protect crucial communities and to provide reproductive reserves for fisheries that hopefully will disperse over wider areas
Maximum Sustainable Yield
In fisheries biology, the maximum catch obtainable per unit time under the appropriate fishing rate
Meiobenthos
Benthic organisms (animals or plants) whose shortest dimension is less than 0.5 millimeters but greater than or equal to 0.1 millimeters
Meiofauna
Animals whose shortest dimension is less than 0.5 millimeters but greater than or equal to 0.1 millimeters
Megaplankton
Planktonic organisms that are greater than or equal to 2,000 micrometers in size
Meroplankton
Organisms that spend part of their time in the plankton but also spend time in the benthos (e.g., planktonic larvae of benthic invertebrates)
Mesopelagic
The 150-2,000 meter depth zone, seaward of the shelf-slope break
Metabolic Rate
The overall rate of biochemical reactions in an organism which is often estimated by rate of oxygen consumption in aerobes
Metamorphosis
Major developmental change as the larva develops into an immature adult
Metapopulation
A group of interconnected sub-populations, usually of sub-equal size and features individuals found in one sub-population which might have been determined by conditions affecting them when they were located in another sub-population
Microbenthos
Benthic organisms (animals or plants) whose shortest dimension is less than 0.1 millimeters
Microfauna
Animals whose shortest dimension is less than 0.1 millimeters
Mixing Depth
The water depth to which wind energy evenly mixes the water column
Mixoplankton
Planktonic organisms that can be classified at several trophic levels and can be photosynthetic but also can ingest other plankton and are heterotrophic
Moderately Stratified Estuary
An estuary in which seaward flow of surface low-salinity water and moderate vertical mixing result in a modest vertical salinity gradient
Monophyletic
Refers to a group of species that all have a single common ancestral species
Mucous-Bag Suspension Feeder
Suspension feeder employing a sheet or bag of mucus to trap particles non-selectively
Mutualism
An interaction between two species in which both derive some benefit
Mutualistic
Conferring reciprocal benefit to individuals of two different associated species
Nanoplankton
Planktonic organisms that are 2-20 micrometers in size
Neap Tides
Tides occurring when the vertical range is minimal
Nekton
Organisms with swimming abilities that permit them to move actively through the water column and to move against currents
Neritic
Seawater environments landward of the shelf-slope break
Net Primary Productivity
Total primary production, minus the amount consumed in respiration
Neuston
Planktonic organisms associated with the air-water interface
Niche
A general term referring to the range of environmental space occupied by a species
Niche Overlap
An overlap in resource requirements by two species
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
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
Nutrients
Those constituents required by organisms for maintenance and growth
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
Out-Welling
The outflow of nutrients from an estuary or salt-marsh system to shelf waters
Over-Dominance
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
Oxygen Technique
The estimation of primary productivity by the measurement of the rate of oxygen increase
Parapatric Specification
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 non-mineral 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
Phenotypic Plasticity
The capacity of an individual to produce different phenotypes under different conditions with 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 species that have a float protruding above the sea surface such as the Portuguese 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 seawater in terms of kilograms of salt per kilograms of water in parts per thousand
Precision
Precision is the repeat-ability 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
Province
A geographically defined area with a characteristic set of species or characteristic percentage representation by given species
Protein Polymorphism
Presence of several variants of a protein of a given type (e.g., a certain enzyme, such as carboxylase) in a population
Pseudofeces
Material rejected by suspension feeders or deposit feeders as potential food before entering the gut
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 seawater, which now happens to be a reference set of diluted seawater samples from the North Atlantic of known salt content
Pteropods
Group of holoplanktonic gastropods
Pycnocline
Depth zone within which sea-water density changes maximally
Q10
Increase of metabolic rate with an increase of 10 ºC
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
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 which are 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
Redox-Potential Discontinuity
That depth below the sediment-water interface marking the transition from chemically oxidative to reducing processes
Red Tide
A dense outburst of phytoplankton (usually dinoflagellates) often coloring water red brown
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 counter-current 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
Rip Current
A concentrated rapid current moving offshore from a beach fronting a long-shore 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 kilograms of dissolved salts in one kilogram of seawater, measured in parts per thousand
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 accrediting 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 Sea Jelly, 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 which are 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
Shelf-Slope Break
Line marking a change from the gently inclined continental shelf to the much steeper depth gradient of the continental slope
Sibling Species
Closely related species that are so similar that they are nearly indistinguishable morphologically
Sigma
Parameter expressing the seawater density and equal to 1 minus the density of seawater, measured at a given temperature and at a pressure of 1 atmosphere
Siphonophores
A group of specialized hydrozoan cnidarians, consisting of large planktonic polymorphic colonies
Sled
A benthic sampling device designed to slide along the sediment surface, digging into the bottom to a depth of at most a few centimeters
Slope
A steep-sloping bottom extending seaward from the edge of the continental shelf and downward toward the rise
Somatic Growth
Growth of the body, exclusive of gametes
Sorting
The range of scatter of particle sizes about the median grain size of a sediment
Space Limited
Description of a situation in which space is a limiting resource
Spatial Auto-Correlation
A situation in which some parameter at any location (e.g., population density) can be predicted through a knowledge of the values of the parameter in other locations
Spatial Distribution
The arrangement of individuals in a space
Specialization
The process of formation of new species
Species
A population or group of populations that are in reproductive contact but are re-productively isolated from all other populations
Species-Area Effect
A regular logarithmic relationship between the number of species in a confined geographic area (e.g., an island) and the area in which the species occur
Species Richness
The number of species in an area or biological collection
Sporophyte
Diploid stage in the life cycle of a plant
Spring Diatom Increase
The major rapid population increase of diatoms, occurring in the spring in temperate-boreal latitudes
Spring Tides
Fortnightly tides occurring when the vertical tidal range is maximum
Stability-Time Hypothesis
Hypothesis that states that higher diversity occurs in habitats that are ancient and stable environmentally
Standing Crop
The amount of living material per unit area or volume; may be expressed as grams of carbon and total dry weight
Stock Recruitment Models
Fishery models that predict the amount of juvenile recruitment as a function of the parent stock
Stratification
In benthos, the presence of different infaunal species at distinct respective horizons below the sediment-water interface
Subtropical
Refers to the portion of the temperate zone closest to the equator
Succession
A predictable ordering of a dominance of a species or groups of species following the opening of an environment to biological colonization
Surface Layer
The layer of the ocean extending from the surface to a depth above which the ocean is homogeneous due to wind mixing
Survivor-Ship Curve
The curve describing changes of mortality rate as a function of age
Suspension Feeder
An organism that feeds by capturing particles suspended in the water column
Swash Rider
Invertebrate that can migrate up and down shore with the rising and falling tide, in order to maintain station at a level that is moist but not overly washed by the waves
Teleplanic Larva
Larva capable of dispersal over long distances, such as across oceans
Temperate
Pertaining to the latitudinal belt between 23º 27′ and 66º 33′ north or south latitude
Tentacle-Tube-Foot Suspension Feeder
Suspension feeder that traps particles on distinct tentacles or tube feet (in echinoderms)
Terminal Anchor
In hydraulically burrowing organisms: any device used to anchor the leading portion of the burrower, permitting muscular contraction to drag the rest of the body into the sediment
Territoriality
Defense of a specified location against intruders
Tertiary Production
The production of living material per unit area (or volume) per unit time by organisms consuming the herbivores
Thermocline
Depth zone within which temperature changes maximally
Thermohaline Circulation
Movement of seawater that is controlled by density differences that are largely explained in terms of temperature and salinity
Tidal Current
A water current generated by regularly varying tidal forces
Tides
Periodic movement of water resulting from gravitational attraction between the earth, sun and moon
Top-Down Control
Refers to food webs where control of a population is mainly explained by consumption by a species or group of species at higher levels of the food chain (e.g., population change of population of Mussels controlled by Sea Star predation)
Trade Winds
Persistent winds at low latitudes in both the Northern & Southern hemispheres, blowing toward the west and the equator
Trench
Deep and sinuous depression in the ocean floor, usually seaward of a continental margin or an arcuate group of volcanic islands
Trophic Level
In a food chain, a level containing organisms of identical feeding habits with respect to the chain (e.g., herbivores)
Tropical
Being within the latitudinal zone bounded by the two tropics (23º 27′ north and south latitude)
Turbidity
The weight of particulate matter per unit volume of seawater
Ultraplankton
Planktonic organisms that are less than 2 micrometers in size
Uniform Spatial Distribution
Situation in which individuals are more evenly spread in space than would be expected on the basis of chance alone
Up-Welling
The movement of nutrient-rich water from a specified depth to the surface
Vertically Homogeneous Estuary
An estuary in which at any given location, wind or tidal mixing homogenizes salinity throughout the water column
Vitamin
Chemical substances required in trace concentrations acting as a co-factor with enzymes in catalyzing biochemical reactions
Viviparous
Refers to development of an organism through the juvenile stage within a parent
Wash Zone
The depth zone in which sediments are disturbed by wave action near the shoreline
Water Mass
A body of water that maintains its identity and can be characterized by such parameters as temperature and salinity
Watershed
The land area that is drained by a river or estuary and its tributaries
Westerlies
Persistent eastward-equatorial winds in mid-latitudes in both the Northern and Southern Hemispheres
Windward
The side of an island that faces a persistent wind
Within-Habitat Comparison
A contrast of diversity between two localities of similar habitat type
Wrack Zone
A bank of accumulated litter at the strand-line
Year-Class Effect
The common domination of a species population by individuals recruited in one reproductive season
Zonation
Occurrence of single species or groups of species in recognizable bands that might delineate a range of water depth or a range of height in the inter-tidal zone
Zooplankton
Animal members of the plankton
Zooxanthellae
A group of dinoflagellates living endosymbiotically in association with one of a variety of invertebrate groups (e.g., corals)