Scientific Glossary

Glossary of terms and abbreviations relevant to the International Seabed Authority and the documents it produces

Please note that this is a constantly evolving document.

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Titlesort descending
Salinity

The total amount of dissolved material (salts) in seawater. Listed as g/kg, ‰, parts per thousand (ppt), or as a dimensionless number without units. Pure freshwater has a salinity of 0, the open ocean is 35-37, and the deep sea has a salinity of approximately 34.9.

Salinometer

An instrument to measure salinity.

Seamount

Isolated sub-surface topographic feature, usually of volcanic origin, of significant height above the seafloor. Seamounts can be subdivided into "true" seamounts (which extend more than 1000m from the seabed), knolls and pinnacles. Compare to guyot. {Figure}.

SeaWIFS

Sea-viewing Wide Field-of-view Sensor. A remote sensing system to provide quantitative data on the colour of the oceans. Small changes in the colour signify various types and quantities of phytoplankton.

Second-Level Impacts

Synonymous with indirect impacts.

Secondary Consumer

A heterotrophic organism that feeds on other heterotrophic organisms. Synonymous with carnivore. Compare to primary consumerand primary producer.

Secondary Impacts

Synonymous with indirect impacts.

SEG

Society of Exploration Geophysicists.

Sessile

Fixed or attached. Used to refer to the organisms which are usually found attached to rock outcrops, including cobalt crusts,polymetallic nodules and polymetallic sulphides. Opposite of errant.

Shelf Break

The point where the Continental Shelf meets the Continental Slope.

Shinkai 6500

Japanese Deep-Sea Research Vehicle. Rated to a depth of 6500m.

Sigsbee Trawl

Synonymous with Agassiz trawl but named after the captain of the ship used by Alexander Agassiz. Also called the Blake trawl.

SOPAC

South Pacific Applied Geoscience Commission.

Spatial Scales

Scales characteristic of dimensions in space. Also pertains to the geographical arrangement of sampling stations. Compare totemporal scales.

Speciation

The evolution of one or more species from an existing species.

Species

The basic unit of taxonomic classification. Classified as organisms that differ from all other groups of organisms but are capable of breeding and producing fertile offspring. One of the components, along with genus, that comprise the scientific name of an organism, for example, the scientific name for humans is Homo sapiens, meaning they belong to the genus Homo and species sapiens.

Species Abundance

The total number of individuals of a species within a given area or community. A measure of species diversity. Compare to species richness.

Species Diversity

The diversity of species within a certain area. Usually given single figure based on species abundance, species richness or a combination of the two. The most commonly used level of biodiversity. Compare to ecosystem diversity and genetic diversity.

Species Richness

The total number of species within a given area or community. A measure of species diversity. Compare to species abundance.

SPM

Suspended Particulate Matter

Stenobathic

Only able to tolerate a narrow range in depth. Opposite of eurybathic. Compare to stenohaline and stenothermic.

Stenohaline

Only able to tolerate a narrow range in salinity. Opposite of euryhaline. Compare to stenobathic and stenothermic.

Stenothermic

Only able to tolerate a narrow range in temperature. Opposite of eurythermic. Compare to stenobathic and stenohaline.

Subhabitat

A visually recognizable component of a larger habitat; for example, tubeworm and mussel beds may be subhabitats of a specific active polymetallic sulphide field; an operational term that facilitates an understanding of the habitat as a whole.

Substrate

The surface on which an organism or geochemical deposit grows. Synonymous with Substratum.

Substratum

Synonymous with Substrate.

Surface Plume

A stream of water containing suspended particles produced as a result of activity on the sea surface and spreads in a zone close to the sea surface. Compare to benthic plume and rain of fines.

Suspension Feeder

Synonymous with Filter Feeder.

Suspension Feeding

Synonymous with Filter Feeding.

Symbiont

One of the organisms in a symbiotic relationship. Often the autotrophic smaller participant, that provides nourishment to the host which is often heterotrophic.

Symbiosis

Two or more organisms living together, usually for mutual benefit. An example is the association at hydrothermal vents between certain bacteria (symbionts) and invertebrates or vertebrates (hosts), in which the symbionts are chemoautotrophic and provide nourishment to the host. The bacteria may be either endosymbiotic or episymbiotic.

Symbiotic

Pertaining to symbiosis.

Synoptic scales

Scales of hydrodynamic variability or events encompassing temporal scales ranging from one week to two months and spatial scalesof one to several hundred kilometres.