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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Title
PAP	Porcupine Abyssal Plain.
PCB	Polychlorinated biphenyl.
Pelagic	Pertaining to the open ocean environment. Divided into five distinct depth regions called the epipelagic, mesopelagic, bathypelagic,abyssopelagic and hadopelagic zones. {Figure}.
pH	A measure of acidity or alkalinity.
Photoautotrophic	Pertaining to photoautotrophy. Synonymous with phototrophic. Compare to chemoautotrophic.
Photoautotrophy	Synonymous with photosynthesis. Compare to chemoautotrophy.
Photosynthesis	The biological synthesis of organic material using light as an energy source. Plants convert carbon dioxide and water, in the presence of chlorophyll and light energy, into carbohydrate food and oxygen. Synonymous with photoautotrophy. Compare tochemosynthesis.
Photosynthetic	Pertaining to photosynthesis. Compare to chemosynthetic.
Phototrophic	Synonymous with photoautotrophic.
Phylum	The second highest level of taxonomic classification containing one or more Classes forming a subgroup of a Kingdom. The plural of Phylum is Phyla.
Phytodetritus	Particulate matter derived from phytoplankton and plants.
Phytoplankton	Microscopic plant plankton that are the primary producers in the oceans, obtaining their energy through photosynthesis. Compare tozooplankton.
Pinnacle	A small seamount, smaller than a knoll. Definitions vary, but usually includes features that extend up to 250m or 500m from the seabed. {Figure}.
Plankton	The plants or animals that live in the water column, incapable of moving against a current. Includes larval stages of benthic and pelagicorganisms, phytoplankton (in surface waters), zooplankton, jellies and other drifting or weakly swimming organisms. Planktonicorganisms can de divided into holoplankton and meroplankton depending on how much of their life cycle they spend as plankton.
Planktonic	Pertaining to the plankton.
Planktotrophic	Organisms which feed on plankton.
Plume	A dispersion of seawater that contains dense sediment particles. Compare benthic plume, surface plume and rain of fines.
POC	Particulate Organic Carbon.
Polychaeta	Marine segmented worms. Some are planktonic although most are benthic. The dominant component of the macrofauna. Synonymous with Polychaete.
Polychaete	Synonymous with Polychaeta.
Polychlorinated Biphenyl	A group of toxic organic compounds that persist in the environment for a long time. Often abbreviated to PCB.
Polymetallic Nodule	One of the mineral resources of the Area consisting of any deposit or accretion of nodules on, or just below, the surface of the deep seabed, which contain manganese, nickel, cobalt and copper. Also called manganese nodules and ferromanganese nodules.
Polymetallic Sulphide	One of the mineral resources of the Area consisting of any deposit of sulphide minerals, formed through hydrothermal activity, which contain concentrations of metals including, inter alia, copper, lead, zinc, gold and silver. These deposits include both active sulphidesand inactive sulphides. They may occur on seamounts, mid-ocean ridges or back-arc ridges exposed on the seafloor or as buried deposits.
POM	Particulate Organic Matter
PON	Particulate Organic Nitrogen.
Porcupine Abyssal Plain	An abyssal plain in the North Atlantic Ocean, west of North Europe. It is approximately the size of the European land mass. Abbreviated to PAP.
ppb	Parts per billion.
ppm	Parts per million.
ppt	Parts per thousand
PRA	Preservation Reference Area
Preservation Reference Area	Synonymous with Preservation Reference Zone. Abbreviated to PRA.
Preservation Reference Zone	Areas representative of the mine site in which no mining shall occur to ensure representative and stable biota of the seabed in order to assess any changes in the flora and fauna of the marine environment caused by mining activities. Compare to Impact Zone andImpact Reference Zone. Synonymous with Preservation Reference Area. Abbreviated to PRZ
Primary Consumer	A heterotrophic organism that feeds directly on a primary producer (autotroph). Synonymous with herbivore. Compare to primary producer and secondary consumer.
Primary Producer	Synonymous with autotroph. Compare to primary consumer and secondary consumer.
Primary Production	Amount of organic material produced from inorganic material by primary producers in a given area in a given period of time.
Prokaryote	Cells or organisms lacking a true nucleus, usually having their DNA in a single molecule and not organized in chromosomes. Compare to eukayote.
Prospecting	The search for mineral deposits in the Area, including estimation of the composition, sizes and distributions of such deposits and their economic values, without any exclusive rights. Compare to exploitation and exploration.
Protozoa	Unicellular heterotrophic animals.
PRZ	Preservation Reference Zone.
Pycnocline	A layer of water in which there is a steep gradient in density with depth. It separates the well-mixed surface waters from the dense waters of the deep ocean. Density of the water is a function of temperature, salinity and, to a lesser extent, pressure. Compare tohalocline, nutricline and thermocline.