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
Ecology

The study of the physical and biological interactions between an organism and its natural environment.

Ecosystem

The living (biotic) and non-living (abiotic) components of an environment that interact.

Ecosystem Diversity

The diversity of biological communities and their chemical and physical environment. The highest level of biodiversity. Compare tospecies diversity and genetic diversity.

EIA

Environmental Impact Assessment.

EISET

Environmental Impact Studies and Equipment Tests (COMRA project)

Embolism

The blood and tissues of fish contain dissolved gases. If fish from the deep ocean are brought to the surface, the decrease in pressure allows the dissolved gas to expand in the form of bubbles (embolism), causing disfiguration and protrusion of the internal organs through the mouth and other orifices.

Endemic

An organism that might be geographically widespread, but is restricted to a specific habitat or region.

Endemism

The degree to which a species is restricted to a particular geographic region; endemism usually occurs in areas that are isolated in some way.

Endofauna

Synonymous with infauna

Endosymbiotic

A symbiotic relationship where the symbiont is found within the tissues of the host (e.g., bacteria living inside tubeworms, clams or mussels)

ENQUAD

Environmental Quality Department (Massachusetts, United States)

Environment

All of the physical, chemical, and biological factors in the area where a plant or animal lives.

Environmental

Pertaining to the environment.

Environmental Impact Assessment

A detailed study and analysis of the effects that a potential action (such as deep sea mining in a particular area) may have on theenvironment. Abbreviated to EIA.

Epaulard

French Autonomous Underwater Vehicle.

Epibenthic

Synonymous with demersal

Epibenthic Sled

A qualitative sampling device which is dragged along the seabed. It is comprised of a flattened mesh bag attached to wide runners to prevent it sinking into the sediment. Designed to collect the smaller organisms at the sediment-water interface.

Epifauna

Animals that live on the seabed, either attached to the seafloor or freely moving over it.

Epifaunal

Pertaining to the epifauna

Epipelagic

Referring to the upper region of the ocean depths, above the mesopelagic, where photosynthesis can occur. Extends from the surface down to 100-200m depending on the localized conditions. Also called the Euphotic Zone. {Figure}.

Episymbiotic

A symbiotic relationship where the symbiont is found living on the outside of the host (e.g., bacteria living on the surface of bresiliid shrimp or alvinellid polychaetes).

EqPac

Equatorial Pacific (Ocean).

Errant

Used to describe the large, active megafauna. Dominated by the Echinodermata, Arthropoda and Fishes. Opposite of sessile.

EU

European Union.

Eukaryote

All organisms except viruses, bacteria and blue-green algae. They have a distinct nuclear membrane surrounding the nucleus and contain chromosomes. Compare to prokaryote.

Eularian Measurement

Measurement of the motion of a fluid by monitoring flow past a fixed point. Compare to Lagrangian measurements.

Euphotic Zone

The upper section of the ocean that receives sufficient light for photosynthesis. In clear oceanic waters, the euphotic zone can extend to a maximum water depth of 200m. Synonymous with epipelagic. Compare to Aphotic Zone

Eurybathic

Able to tolerate a wide range in depth. Opposite of stenobathic. Compare to euryhaline and eurythermic

Euryhaline

Able to tolerate a wide range in salinity. Opposite of stenohaline. Compare to eurybathic and eurythermic

Eurythermic

Able to tolerate a wide range in temperature. Opposite of stenothermic. Compare to eurybathic and euryhaline.

Eutrophic

High nutrient concentrations supporting high productivity. Compare to oligotrophic.

Exoskeleton

The skeleton or supporting structure, on the outside of an organism.

Expendable Bathythermograph

A weighted probe dropped into the sea that transmits temperature readings as it falls through the water column to produce graphs of temperature against depth. The probe is not recovered. Abbreviated to XBT.

Expendable CTD Probe

A weighted CTD probe dropped into the sea that transmits readings as it falls through the water column to produce graphs of conductivity (a measurement of salinity) and temperature against depth. The probe is not recovered. Used when the use of normalCTD apparatus is not practical. Abbreviated to XCTD.

Exploitation

The recovery for commercial purposes of mineral deposits in the Area and the extraction of minerals therefrom, including the construction and operation of mining, processing and transportation systems, for the production and marketing of metals. Compare toexploration and prospecting.

Exploration

Searching for mineral deposits in the Area with exclusive rights, the analysis of such deposits, the use and testing of recovery systems and equipment, processing facilities and transportation systems, and the carrying out of studies of the environmental, technical, economic, commercial and other appropriate factors that must be taken into account in exploitation. Compare to exploitation andprospecting.

Extant

A species which still occurs. Opposite of extinct.

Extinct

A species that no longer occurs anywhere in the world. Opposite of extant. Compare to extirpated.

Extirpated

A species that no longer occurs in a specific location or region. Compare to extinct.