Glossary

sablefishAnoplopoma fimbria

saithePollachius virens

salinitythe total amount of salt dissolved in seawater; the units most often used are parts per thousand (ppt) but practical salinity unit (psu) is now the accepted standard in oceanography. An average salinity value for seawater is 35 ppt (psu) or 35 parts of salt in 1000 parts of water.

salt domesa layer of salt in a domed structure that was formed beneath the Earth's surface by the movement of salt over long periods of time. Salt domes are often associated with oil and gas deposits.

samplea subset of the population.

sample sizethe number of individuals or items in a subset or sample of the population from which estimates of various statistical measures of the whole population are calculated.

sampling frequencythe number of samples per second; how often a sample is taken

sand fiddler crabUca pugilator

sardinessmall, silvery, slender fish of the herring family that have one short dorsal fin and no scales on their heads

Sargassum or Gulfweeda type of brown algae (of the genus Sargassum) that have a branching thallus (body) with lateral outgrowths differentiated as leafy segments, air bladders, or spore-bearing structures

satellite altimetrysatellite radar altimeters measure the ocean surface height (sea level) by measuring the time it takes a radar pulse to make a round-trip from the satellite to the sea surface and back. Features on the sea floor such as mountains add extra pull to Earth's gravity field, drawing more water around them and bulging the sea surface outward. The(...)

saturate when no more of something can be dissolved, or the degree or extent to which something is dissolved or absorbed compared with the maximum possible, usually expressed as a percentage

scattered/scatteringthe diffusion of the sonar signal in many directions through refraction, diffraction and reflection, primarily due to the material properties of the seafloor. Scattering is one of the causes of attenuation in sonar, resulting in signal weakening.

scatterer an object that reflects sound energy, can be a particle in seawater or the sea surface or the seafloor

scatteringwhen the path of a sound wave is broken up by objects (volume scattering) or the sea floor or sea surface (boundary scattering)

Scholte wave a surface wave causing elliptical motion at the interface. Found at an interface between a solid and an elastic medium such as the seafloor and water. Also called ground roll.

schoola large group of marine animals, for example fish, that swim together. The appearance of a large number of individuals may ward off potential predators.

Sciaenidaefamily of fishes that contains approximately 270 species distributed in the Atlantic, Pacific, and Indian Oceans. This family is commonly known as the drums, which are renowned for their sound producing ability.

scientific methodthe orderly process by which scientists ask questions about the natural world and test their observations

scuttleto sink (a vessel) deliberately.

sea otterEnhydra lutris

sea statecondition of the surface of the ocean, measured on a scale 0-9, categorized by wave height.

Sediment solid particles of inorganic or organic material deposited in water on the bottom

sei whaleBalaenoptera borealis

seismicrelates to an earthquake, earth vibration or volcano

seismic reflectiona technique for examining the layers of the seafloor that uses the sound energy that is reflected by different layers in the seafloor.

seismic refractiona technique for examining the layers of the seafloor that uses the sound energy that is refracted by different layers in the seafloor.

seismic wavea wave of energy caused by the sudden movement of rock, as in an earthquake, or by an explosion. Seismic waves travel trough the Earth and are recorded by a seismometer.

seismometeran instrument that records ground movement; used to detect and measure earthquakes

semi-terrestrialliving mostly on land but requiring water and/or a moist environment (esp. as a breeding site). Most amphibians (e.g. frogs) and many crustaceans (e.g. crabs) are semi-terrestrial.

sensorineural hearing losshearing loss due to damage to the nerves or inner ear structures

sensory hair cellsbundles of hair like projections (cilia) located on the surface of the inner ear that become stimulated by movement of the otolith against them. Stimulation of the hair cells results in sending a signal to the brain which is interpreted as sound.

sequestration the process of depositing carbon from the atmosphere in a pool , or reservoir. In terms of carbon sequestration, it presumes a reservoir that is not easily transferable to the atmosphere or only transfers over a long time period.

setaea stiff hair, bristle, or bristle like part on an organism.

sexual dimorphismdistinct difference in size or appearance between male and female sexes of an animal

shadow zonea region of low sound intensity that sound waves traveling away from a source in the ocean do not reach, usually because the sound waves are refracted away from that region

shear wave a transverse wave in the seafloor or solid Earth

shelf-edged habitatsocean habitat on the edge of the continental shelf

shoala large school of fish

shock wavea fully developed compression wave of large amplitude, across which density, pressure, and particle velocity change drastically.

side scan sonarsonar is an acronym for sound navigation and ranging equipment. Sonar systems use sound waves to detect underwater objects by listening to the returning echoes. Side scan sonar uses the strength of the returning echo, not the travel time, to map the seafloor and identify objects on the seafloor.

signalsound that is used for a specific task, such as to convey information.

signal excessthe amount (in decibels) by which the signal- to-noise ratio (SNR) exceeds the detection threshold (DT).

signal processinganalyzing sounds from a receiver to detect and classify sound sources

signal processingthe analysis of signals to obtain information.

signal-to-noise (SNR) ratiothe ratio that compares the received level of a sound signal and the background noise level. For example, it is easy to hear conversations in a quiet room, where the signal-to-noise ratio is high, but it is difficult to hear conversations at a noisy party, where the signal-to-noise ratio is low.

signature sounda unique sound that is associated with a specific sound source

signature whistletonal sounds produced by whales and dolphins that are unique to a particular individual and distinct from any other member of the group. Signature whistles provide a way to recognize individuals and help maintain group cohesion.

silver perchBairdiella chrysoura

sine wavea sinusoid; a mathematical curve defined in terms of the sine trigonometric function

sinusoid a sine wave; a mathematical curve defined in terms of the sine trigonometric function

sireniansgroup of mammals that includes manatees and dugongs

slippery dick wrasse Halichoeres bivittatus

smolta young salmon (or trout) at the stage of development when it assumes the silvery color of the adult and is ready to migrate to the sea.

snapping shrimpAlpheus heterochaelis

SOFAR channelSOFAR stands for SOund Fixing And Ranging. The sound speed minimum at 800-1000 meters of water depth is called the deep sound channel or, more historically, the SOFAR channel.

sonaran acronym for SOund Navigation And Ranging equipment. Sonar systems use sound waves to detect underwater objects by listening to the returning echoes. The distance to the object or the seafloor can be calculated by measuring the time between when the signal is sent out and when the reflected sound, or echo, is received.

sonar pulse each individual component of a sonar signal

sonar waveform the combined components of a sonar signal, which includes all the sonar pulses

sonar waveform duration the length of time of the sonar waveform

sonic musclea muscle that is attached to the swim bladder. Rapid flexure of the sonic muscle against the swim bladder produces drum-like sounds commonly associated with courtship and spawning behavior.

sonic muscle - swim bladdera combined mechanism used by fishes to produce sound. The swim bladder is a gas filled organ primarily used for buoyancy control and is also important for hearing in some fishes. The sonic muscle is attached to the swim bladder. Rapid flexure of the sonic muscle against the swim bladder produces drum-like sounds commonly associated with(...)

soniferoussound producing

sonobuoyinstrument that is dropped into the ocean (from either an aircraft or ship) to record underwater sounds. It includes a hydrophone and a radio transmitter to send sound signals back to the aircraft or ship. The U.S. Navy uses this instrument to listen for enemy submarines. Sonobuoys may also be used to record marine mammal calls and listen for(...)

sonogramgraphic presentation of a sound. A sonogram plots the frequency vs. time and represents the different intensity of the frequencies with different colors. It is similar to a contour map or bathymetric map where the different colors represent different water depths. Also called a spectrogram

sonoluminescencethe production of light as a result of the passing of sound waves through a liquid medium. The sound waves cause the formation of bubbles that emit bright flashes of light when they collapse.

sound channelan area of slow sound speed that causes sound waves to become focused at this water depth

sound channel axisdepth of the minimum sound speed within the sound channel. Sound waves cycle above and below the axis as they move through the sound channel.

sound exposure level (SEL)the decibel level of the time integral (summation) of the squared pressure over the duration of a sound event; units of dB re 1 µPa2/s

sound fieldthe level of sound at different distances and depths from the source

sound intensity level10 times the logarithm of the ratio of the intensity of a sound wave to a reference intensity; also known as intensity.

sound level10 times the logarithm of the ratio of the mean-square pressure of a sound to the square of a reference sound pressure. Sound pressure level will usually be shortened to sound level on the DOSITS website. Sound pressure level is given in relative units named decibels (dB). Sound pressures for transient signals are sometimes given as peak or(...)

sound receptorsomething that receives sound; sound receiver

sound sourcesomething that creates sound

sound spreading lossthe decrease in intensity that occurs when a sound wave expands as it moves away from a source

Sound Surveillance System (SOSUS)a network of hydrophones mounted on the seafloors of the North Atlantic and North Pacific oceans maintained by the US Navy

soundscapeacoustic environment as perceived or experienced and/or understood by a listener. (ISO Technical Committee on Acoustics, Noise Subcommittee, ISO 12913-1:2014).

source arraymultiple sound sources combined to operate together for a specific purpose

source levelthe amount of sound radiated by a sound source. It is defined as the intensity of the radiated sound at a distance of 1 meter from the source, where intensity is the amount of sound power transmitted through a unit area in a specified direction. Source level is given as a relative intensity in units named decibels (dB). In underwater sound,(...)

Southern California Offshore Range (SCORE)a state-of-the-art facility that provides training and testing services to the U.S. Navy’s Pacific Fleet. The underwater tracking range is located west of San Clemente Island, CA, and consists of 84 bottom-mounted hydrophones that provide a coverage area of approximately 660 square nautical miles. Similar to AUTEC, a Marine Mammal(...)

southern right whaleEubalaena australis

Sparkera sound source that uses an electric spark to generate a broadband signal.

spatial resolutionthe minimum difference or distance between two measured or computed values or objects that can be distinguished. It defines the limit of accuracy for a technique.

spatulatehaving a narrow base and a broad body (spade-shaped).

spawningto produce, release, or deposit eggs for reproduction

specific acoustic impedancethe ratio of acoustic pressure to the associated particle speed in a medium.

spectral the frequency composition of sound.

spectral characteristics the frequency components of an acoustic signal

spectrograma graphic presentation of a sound. A spectrogram plots the frequency vs. time and represents the different intensity of the frequencies with different colors. It is similar to a contour map or bathymetric map where the different colors represent different water depths. Also called a sonogram

spectruma catalog of the amplitude of a signal as a function of frequency or pitch, with graphics showing low frequencies on the left of the x-axis and high frequencies on the right.

sperm whalePhyseter macrocephalus

spermaceti organan elongated connective tissue sac in the forehead of the sperm whale that contains a waxy fluid called spermaceti

spherical spreadingenergy spreading out from a sound source in the shape of a sphere; the power is radiated equally in all directions from the sound source

spinner dolphinStenella longirostris

Spiny LobsterPalinurus elephas

spratSprattus sprattus

spreading lossa decrease in the intensity of a wave as it spreads out from a source

spy-hoppinga common whale activity in which they lift their heads above the surface of the water and observe what is happening on the surface. Whales will often spin around in order to observe in all directions.

squidmollusks of the family Cephalopoda that are a favorite food of the sperm whale

standard deviationan estimate of the variability of a set of measurements about the mean value; it is calculated by computing the square root of the variance.

standard deviation of the meanan estimate of the variability of the mean value computed from a specific set of measurements; it is calculated by dividing the standard deviation of the measurements by the square root of the number of measurements; also often called the standard error of the mean.

startle responsea largely involuntary, defensive response to a sudden and/or threatening stimuli, such as a flash of light, a sudden movement, or loud noise. In fishes, this behavior is often displayed as a sudden bending of the body, and is a characteristic escape response.

static diffusionwhen particles move from a region of higher concentration to a region of lower concentration

statistically significantfindings of an experiment or study that have a low probability of being due to chance alone

statisticsmathematical analysis that is used to explain and compare numerical data. This analysis helps make broader generalizations about a population from a smaller number of specific observations.

statocysta sac-like structure containing a mineralized mass (statolith) in association with numerous sensory cells.

stepsa break or irregular change in frequency of a whistle.

stereoshort for stereophonic: a sound-reproduction system that uses two or more separate channels to give a more natural distribution of sound.

stereocilialong, flexible hair-like structures that occur as a brush border on the surface of some membranes

stereociliary bundlesgroups of hair-like projections on the upper surface of a hair cell. When stereocila bend, they trigger a release of chemicals that initiates the electrical signal (neural impulse) that is carried to and processed by the brain.

stereotypedfixed or settled in form.

stewardshipthe conducting, supervising, or managing of something, especially, the careful and responsible management of something entrusted to one's care.

strandingan event where an aquatic animal, especially a marine mammal, lands on a beach or becomes stuck in shallow water, is dead or sometimes alive, and probably in distress.

stratificationseparation of water layers based on strong density differences

streaked gurnardsTrigloporus lastoviza

streamersa long (2000-6000 m) string of hydrophones typically used with air-gun arrays

stresswhen an optimal steady state is threatened by internal and/or external forces, and is counteracted by a physiological or biological response (to maintain/establish equilibrium).

stress responsethe natural coping mechanism that allows the body to deal with stressful events. A group of physiological and behavioral processes enable an animal to adapt to changes in their environment.

stressoranything that causes the body to respond by releasing stress hormones.

stridulationto produce a sound by rubbing two body parts together. Some fish make a shrill creaking noise by rubbing together bodily structures, especially skeletal parts.

striped cusk eel Ophidion marginatum

striped dolphinStenella coeruleoalba

stripersMorone saxatilis

sub-arcticrelating to the region immediately south of the Arctic Circle.

subduction zonesplaces where two tectonic plates move toward each other, and one plate plunges beneath the other plate. Often ocean crust is subducting beneath continental crust

submarineunderwater

submarine canyonnarrow, steep-sided valleys on the seafloor.

subsonica frequency that is below the audible range

substratethe surface or medium on which an organism lives or grows, or the material on the bottom of the ocean.

substratum (substrate)the surface that an organism grows on or is attached to

supersaturatedmore highly concentrated than is normally possible under given conditions of temperature and pressure

surf zoneThe zone within which waves approaching the coastline start breaking; also called the breaker zone.

surface reverberationsound scattering that occurs on or at the sea surface

surface wave a sound wave (or seismic wave) that travels only at an interface boundary

Surveillance Towed Array Sensor System (SURTASS)a passive sonar system used to listen for noises produced by submarines. The system consists of a long string of underwater hydrophones that are towed behind a ship and pick up sounds in the ocean.

SUS (Signal, Underwater Sound)an explosive sound source used by the U.S. Navy that consists of 0.82-kg (1.8-lb) of TNT explosive material.

swathan area shaped like a broad strip.

Swift scallop Chlamys swifti

swim bladdera gas filled organ that is primarily used for buoyancy control but is also important for hearing in some fishes.

swim bladder (also called an air bladder)an expandable, gas-filled sac that helps fish maintain buoyancy in the water. This organ is also important for hearing in some species of fish.

symbiotichaving an interdependent relationship that benefits both parties involved.

synapsea junction between a nerve cell and another nerve cell or a nerve fiber or a sensory receptor