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 ascending

International Young Gadoid Pelagic Trawl


International Whaling Commission


Intertropical Convergence Zone (Pacific Ocean)


Of equal temperature.


Line of constant temperature. Compare to isobar.


Line of constant pressure. Compare to isotherm.


International Organization for Standardization


International Seabed Authority


Impact Reference Zone.


Impact Reference Area


Institute of Oceanographic Sciences (United Kingdom)

Ion-Exchange Chromatography

A quantitative method for separating charged molecules of various sizes, from large proteins to small nucleotides.


Interoceanmetal Joint Organization (Bulgaria, Cuba, Czech Republic, Russia Federation, Slovak Republic, Poland). One of the groups granted a contract for the exploration of polymetallic nodules. Other contractors listed here.


Intergovernmental Oceanographic Commission (UNESCO)


Organisms not possessing a backbone. Approximately 95% of the animal kingdom. Compare to vertebrate.

Invasive Species

An introduced species that out-competes native organisms for space and/or resources. Synonymous with alien species.


Pertaining to, or occurring within, the spaces between sediment particles.

International Seabed Authority

An autonomous international organization established under the 1982 United Nations Convention on the Law of the Sea and the 1994 Agreement relating to the Implementation of Part XI of the United Nations Convention on the Law of the Sea. The Authority is the organization through which States Parties to the Convention shall, in accordance with the regime for the seabed and ocean floor and subsoil thereof beyond the limits of national jurisdiction (the Area) established in Part XI and the Agreement, organize and control activities in the Area, particularly with a view to administering the resources of the Area. Abbreviated to ISA. Divided into the Assembly, the Council, the Legal and Technical Commission, the Finance Committee and the Secretariat. {Web Page}


Pertaining to, or derived from, non-biological material. Opposite of organic.


Pertaining to the infauna.


Organisms that live within the sediment. Synonymous with endofauna. Compare to epifauna.

Indirect Impacts

Impacts on the environment that are not a direct result of an activity, often produced away from the activity or as a result of a complex pathway (physical, chemical, biological). Synonymous with second-level impacts, third-level impacts, and secondary impacts.


Indian Deep-Sea Environment Experiment.

Inactive Sulphides

Polymetallic sulphides through which warm water is no longer flowing into the overlying seawater (i.e., they are "cold"). Disturbance of these sulphides may result in renewal of hydrothermal fluxes into the water column, turning inactive sulphides into active sulphides(hence the concept of "dormant" sulphides). Synonomous with dormant sulphides. Opposite of Active Sulphides

Impact Zone

Zone where impacts (direct, indirect, cumulative, and/or interactive) result from an activity. Compare to Impact Reference Zone andPreservation Reference Zone.

Impact Reference Zone

Areas which are representative of the environmental characteristics of a particular region to be used for assessing the effect of activities in that region on the marine environment. Compare to Impact Zone and Preservation Reference Zone. Synonymous withImpact Reference Area. Abbreviated to IRZ

Impact Reference Area

Synonymous with Impact Reference Zone. Abbreviated to IRA.

Impact Interactions

The reactions between impacts (between the impacts of just one action and/or between the impacts of multiple actions in the Area).


Institut français de recherche pour l'exploitation de la mer (French Research Institute for Exploitation of the Sea). One of the groups (jointly with AFERNOD) granted a contract for the exploration of polymetallic nodules. Other contractors listed here.


Ion-Exchange Chromatography.


International Council for the Exploration of the Sea