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.

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Z
Titlesort descending
AAA

Atomic Absorption Analysis.

AABW

Antarctic Bottom Water.

AAS

Atomic Absorption Spectroscopy.

Abiotic

Nonliving (e.g. The chemical, physical and geological factors of an environment). Opposite of biotic.

Abyssal

The deep-sea. The upper boundary has been defined as anywhere between 1000m and 4000m, the lower boundary usually considered to be 6000m.

Abyssal Plain

The deep ocean floor with a gradient of less than 1:1000 (approximately 0.05°). Extends seaward from the Continental Rise.{Figure}

Abyssobenthic

Pertaining to the seabed in the abyssal zone. Found below the bathybenthic zone.

Abyssopelagic

Referring to the majority of the deep-sea open ocean. It is separated from the overlying bathypelagic by the 4 C isotherm and from the underlying hadopelagic at about 6000 meters. {Figure}.

Accelerator Mass Spectrometry

An ultra sensitive quantitative technique for measuring isotopic ratios. It is typically used for determining the ratio of the abundant to rare isotopes of certain elements. Can measure ratios as low as 1 in 1015 for carbon. Its advantages include using small samples, fast analysis time and it is far more sensitive than all other mass spectrometry techniques. Abbreviated to AMS.

Acoustic Doppler Current Profiler

An instrument used to measure ocean currents. It transmits high frequency acoustic signals which are backscattered from plankton, suspended sediment, and bubbles, all of which are assumed to be traveling with the mean speed of the water. The Doppler shift in the backscatter echo allows the water velocity to be determined. Usually abbreviated to ADCP.

Active Sulphides

Polymetallic sulphides through which warm water is flowing. Active sulphides deliver reduced compounds (e.g., sulphide) to the seafloor-seawater interface where they can be oxidized or otherwise autotrophically metabolized by free-living or symbiotic micro-organisms. Synonymous with hydrothermal vents. Opposite of Inactive Sulphides.

ADCP

Acoustic Doppler Current Profiler.

Adenosine Triphosphate

A complex organic compound which serves for short-term energy storage and conversion in all organisms. Usually abbreviated toATP. The amount of ATP present can be used as a measure of total microbial biomass in the sediment, as it corresponds to the number of active cells, most of which are bacteria.

Advection

Horizontal or vertical movement of water as a current.

Aerobic

Life or processes that require, or are not destroyed by, oxygen. Opposite of Anaerobic.

AFERNOD

Association française pour l'exploration et la recherche des nodules (French Association for Exploration and Research of Nodules). One of the groups (along with IFREMER) granted a contract for the exploration of polymetallic nodules. Other contractors listedhere.

Agassiz Trawl

Qualitative sampling device used to sample large numbers of the megabenthos and benthopelagic fauna It is a double sided trawl adapted from the fishing gear of coastal fishermen. Named after the American naturalist Alexander Agassiz. Also called the Blake trawl or Sigsbee trawl (the name of the ship used by Alexander Agassiz and the captain of that ship respectively).

Alien Species

Synonymous with Invasive Species.

Alvin

American Deep-Sea Research Vehicle. Rated to a depth of 4500m.

AMS

Accelerator Mass Spectrometry.

Anaerobic

Life or processes that do not require oxygen, or that are not destroyed by a lack of it. Opposite of aerobic.

ANOVA

Analysis Of Variance. A statistical technique to compare the means of two or more different groups.

Anoxic

Without oxygen. Compare to Oxic and Hypoxic.

Antarctic Bottom Water

The densest water in the oceans formed around Antarctica. Has a temperature of approximately -0.4°C and salinity of approximately 34.66‰. Abbreviated to AABW.

Anthropogenic

Caused by, or as a result of, human activity.

Aphotic Zone

The deeper regions of the water column where there is insufficient light for photosynthesis to occur. Compare to Euphotic Zone.

Archaea

One of the three primary kingdoms of living organisms comprising methanogenic and sulphur-dependant bacteria.

Area

The seabed and ocean floor and subsoil thereof, beyond the limits of national jurisdiction.

ATESEPP

Auswirkungen technischer Eingriffe in das Ökosystem der Tiefsee im Süd-Ost-Pazifik vor Peru (Impacts of potential technical interventions on the deep-sea ecosystem in the Southeast Pacific) (German programme)

Atomic Absorption Analysis

Synonymous with Atomic Absorption Spectroscopy. Abbreviated to AAA.

Atomic Absorption Spectroscopy

A quantitative analytical method for determining the presence, and concentration, of metals in liquid samples. Can detect concentrations as low as 100ppb. Abbreviated to AAS.

ATP

Adenosine triphosphate.

Authority

Abbreviation of International Seabed Authority

Autonomous Undersea Vehicle

Synonymous with Autonomous Underwater Vehicle.

Autonomous Underwater Vehicle

Unmanned, untethered research submersible that can work autonomously once programmed with certain criteria. Abbreviated toAUV. For example, Autosub and Epaulard. Compare to Remotely Operated Vehicles and Deep-Sea Research Vehicles.

Autosub

British Autonomous Underwater Vehicle.

Autotroph

An organism which synthesizes its own organic material through Chemosynthesis or Photosynthesis. Compare to Heterotroph

Autotrophic

Pertaining to an Autotroph. Compare to Heterotrophic.

AUV

Autonomous Underwater Vehicle.