Environment, Ocean Science and the Natural World

Marine environmental science, pollution and conservation glossary

The science of the marine environment under stress, distinct from MARPOL compliance: microplastics in the gyres, the fate and weathering of spilled oil, eutrophication and hypoxic dead zones, persistent organic pollutants, underwater radiated noise, and harmful algal blooms. Conservation covers marine protected areas, coral bleaching, acidification effects on calcifiers, invasion ecology, and blue carbon, with GESAMP, UNEP, ICES, IUCN, and OBIS.

212 defined terms.

A

Abalone Recovery Program: Conservation effort for depleted abalone stocks.
Acidification (Coastal): pH decline in coastal waters from CO2 uptake and nutrient inputs.
Acoustic Deterrent Device (ADD): Underwater sound device to reduce marine mammal bycatch or interactions.
Active Ingredient (Antifouling): Biocide in antifouling paint such as copper or zinc pyrithione.
Adaptive Management: Iterative resource management approach incorporating monitoring and learning.
AFS Convention: International Convention on the Control of Harmful Anti-fouling Systems on Ships, 2001.
Algal Bloom: Rapid increase in algal abundance, sometimes harmful.
Ambient Water Quality Criteria: Numerical limits for pollutants to protect aquatic life.
Anoxia: Complete absence of dissolved oxygen in water or sediment.
Anthropogenic: Originating from human activity.
Antifouling Paint: Coating preventing marine organism attachment to ship hulls.
Aquaculture Discharge: Effluent from fish or shellfish farms.
Aragonite: Mineral form of calcium carbonate used by many marine calcifiers.
Aragonite Undersaturation: Conditions corrosive to aragonite shells.
ASCOBANS: Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas.
Aspirational Target 30 by 30: CBD goal to protect 30 percent of land and sea by 2030.

B

Background Concentration: Natural baseline level of a substance.
Ballast Water Exchange: Mid-ocean exchange to reduce introduction of coastal species.
Ballast Water Management Convention (BWMC): IMO treaty regulating ship ballast water.
Benthic Community: Organisms inhabiting the seabed.
Bioaccumulation: Buildup of substances in an organism over time.
Bioconcentration Factor (BCF): Ratio of contaminant concentration in an organism to that in water.
Biodiversity Hotspot: Region with exceptional concentration of species and high threat.
Biofouling: Accumulation of organisms on submerged surfaces.
Biofuel Slick Effect: Surface films modifying gas exchange; relevant to pollution studies.
Biogenic Habitat: Habitat structured by living organisms such as reefs or seagrass.
Biomagnification: Increase in contaminant concentration moving up a food chain.
Biotoxin: Toxic compound produced by an organism, including algal toxins.
Black Carbon: Issue under MARPOL Annex VI, addressed through PPR work.
Blue Carbon: Carbon stored in coastal ecosystems such as mangroves, seagrass, and saltmarsh.
Bonn Agreement: North Sea cooperation on pollution preparedness and response.
Bonn Convention (CMS): Convention on the Conservation of Migratory Species of Wild Animals.
Buoy Mooring Spill Risk: Risk of pollution at single buoy moorings.
By-Catch: Unintended catch of non-target species during fishing.
By-Product PCB: Polychlorinated biphenyl arising as a contaminant in some industrial processes.

C

Calcification Rate: Rate at which calcifying organisms build carbonate skeletons.
CARIACO Time-Series: Long-term biogeochemical study in the Cariaco Basin.
Caribbean SPAW Protocol: Specially Protected Areas and Wildlife Protocol of the Cartagena Convention.
Carrying capacity: Maximum cargo a vessel can carry, in deadweight or volume.
Cartagena Convention: Regional Convention for the Protection and Development of the Wider Caribbean.
CBD (Convention on Biological Diversity): UN treaty on biodiversity conservation and sustainable use.
Cetacean Sanctuary: Designated area protecting whales and dolphins.
Chlorophyll Bloom: Visible algal bloom often imaged from satellite.
CITES: Convention on International Trade in Endangered Species of Wild Fauna and Flora.
Coastal Squeeze: Loss of intertidal habitat between rising seas and fixed defenses.
Coral Bleaching: Loss of symbiotic algae from corals under thermal stress.
Coral Reef Resilience: Capacity of a reef to recover from disturbances.
Critical Habitat: Area essential to a listed species under conservation law.

D

Dead Zone: Hypoxic or anoxic area incapable of supporting most marine life.
Debris Tracking: Modeling and observation of marine litter trajectories.
Decommissioning Pollution: Environmental impact of removing offshore infrastructure.
DEHP: Common phthalate plasticizer studied as marine micropollutant.
Demersal Habitat Disturbance: Alteration of seabed habitat by bottom contact gear.
Deposit Feeders: Organisms feeding on sediment-bound organic matter.
Desalination Brine Discharge: Concentrated salt effluent affecting coastal habitats.
Detritus: Dead particulate organic material in marine ecosystems.
Diagenesis (Pollutant): Chemical change of pollutants buried in sediments.
Dispersant: Chemical applied to oil spills to break oil into smaller droplets.
Dispersion Modeling: Simulation of pollutant transport in air or water.
Dredged Material Disposal: Placement of dredged sediments under regulatory permits.
Dumping at Sea: Disposal of wastes at sea, regulated under the London Convention.

E

Eco-Classification: Categorization of water bodies by ecological status under frameworks such as WFD.
Ecological Quality Objective (EcoQO): OSPAR target for environmental indicators.
Ecological Risk Assessment: Estimation of ecological effects from stressors.
Ecosystem Approach to Management (EAM): Management considering whole ecosystems and human uses.
Ecosystem Service: Benefit people obtain from ecosystems.
Effluent: Discharged wastewater or industrial outflow.
EIA (Environmental Impact Assessment): Process evaluating environmental effects of proposed projects.
Eichhornia Invasion: Spread of water hyacinth in coastal lagoons.
Emerging Contaminant: Substance recently recognized as a pollutant of concern.
Endangered Species Act (ESA): US law protecting threatened and endangered species.
Endocrine Disruptor: Chemical interfering with hormonal systems of organisms.
Environmental Flow: Water flow regime needed to sustain aquatic ecosystems.
Eutrophication: Nutrient enrichment leading to excessive plant or algal growth.
Excess Nitrogen Loading: Nitrogen delivery beyond ecosystem assimilation capacity.

F

Faecal Indicator Bacteria: Bacteria such as E. coli used to assess water quality.
Fauna Monitoring: Survey and tracking of marine animals.
Fisheries Bycatch Reduction: Measures to reduce non-target catch.
Forage Fish: Small pelagic fish such as anchovies and sardines, key to marine food webs.
Foul Release Coating: Coating that prevents firm attachment of biofouling.
Fragmentation (Plastic): Breakdown of plastic into smaller pieces.

G

GBO (Global Biodiversity Outlook): CBD periodic assessment of biodiversity status.
GESAMP: Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection.
Ghost Fishing: Continued capture of marine animals by lost or abandoned gear.
Global Marine Litter Partnership (GPML): UNEP-led partnership addressing marine litter.
Green Algae Bloom: Macroalgal bloom such as Ulva green tides.
Grey Whales Population Recovery: Conservation outcome under various national programs.

H

HAB (Harmful Algal Bloom): Bloom producing toxins or harmful biomass impacts.
Habitat Restoration: Active rehabilitation of degraded marine habitats.
Habitats Directive: EU directive establishing Natura 2000 network.
Halogenated Compound: Organic compound containing halogens, often persistent.
Heavy Metal: Metals such as mercury, cadmium, and lead with toxicological concern.
HELCOM: Helsinki Commission protecting the Baltic Sea marine environment.
Holdfast Habitat: Habitat formed by kelp and seaweed holdfasts.
Hypoxia: Dissolved oxygen below threshold needed for many marine species, often less than 2 milligrams per liter.

I

ICES: International Council for the Exploration of the Sea, providing scientific advice.
IMMA (Important Marine Mammal Area): IUCN-designated area for marine mammal conservation.
Inorganic Nutrient: Nitrate, ammonium, phosphate, and silicate dissolved in seawater.
Integrated Coastal Zone Management (ICZM): Coordinated approach to coastal area governance.
International Whaling Commission (IWC): Body regulating whaling and cetacean conservation.
Invasive Alien Species: Non-native species causing ecological or economic harm.
Inversion (Estuarine): Reversed salinity gradient under drought conditions.
IUCN: International Union for Conservation of Nature.
IUCN Red List: Global threat status list for species.

J

Joint Programming Initiative Healthy and Productive Seas (JPI Oceans): European research coordination on marine challenges.
Jurisdictional Waters: Maritime zones under coastal state jurisdiction.

K

K-strategist Species: Species with low reproductive rates and high parental investment, often conservation priorities.
Kuwait Convention: Regional Convention for Cooperation on the Protection of the Marine Environment from Pollution in the ROPME Sea Area.

L

Larval Dispersal: Transport of larvae by ocean currents, influencing connectivity.
LC/LD50: Concentration or dose lethal to 50 percent of test organisms.
LDC: London Dumping Convention; see London Convention.
Lead Shielding (Marine): Use of lead as ballast historically; legacy pollution concern.
Light Pollution (Coastal): Artificial light disturbing turtle nesting and other species.
Litter Index: Density of marine litter on beaches or seabed.
London Convention: 1972 convention on the prevention of marine pollution by dumping of wastes.
London Protocol: 1996 protocol updating the London Convention with a reverse-list approach.

M

Macroplastic: Plastic debris larger than 5 millimeters.
Manatee Sanctuary: Protected areas safeguarding manatee populations.
Mangrove Restoration: Replanting and rehabilitation of mangrove forests.
Marine Debris: Solid persistent wastes in the marine environment.
Marine Litter Watch: EEA-supported citizen science marine litter monitoring.
Marine Protected Area (MPA): Geographically defined area managed for conservation.
Marine Reserve: Highly protected MPA with strict no-take rules.
MARPOL Annex VI: Air pollution and energy-efficiency annex.
Maximum Sustainable Yield: Largest yield that can be taken from a stock indefinitely.
Mediterranean Action Plan (MAP): UNEP regional plan for Mediterranean protection.
Mercury (Marine): Heavy metal pollutant addressed under the Minamata Convention.
Methylmercury: Organic mercury form that biomagnifies in marine food webs.
Microbead: Small plastic particle, often in cosmetic products.
Microplastic: Plastic particle smaller than 5 millimeters.
Mitigation Hierarchy: Sequence of avoid, minimize, restore, and offset for environmental harm.
Mortality Event: Sudden die-off of marine animals, sometimes from toxins or disease.

N

Natura 2000: EU network of protected areas under the Birds and Habitats Directives.
Natural Resource Damage Assessment (NRDA): US process for quantifying damages from pollution incidents.
Nautical Mile Buffer: Distance-based protection around sensitive features.
No-Take Zone: MPA where extractive activities are prohibited.
Noise Budget: Cumulative underwater noise assessment.
NOWPAP: Northwest Pacific Action Plan under UNEP.
Nutrient Loading: Input of nitrogen, phosphorus, or silica to a water body.

O

OBIS: Ocean Biodiversity Information System under IOC-UNESCO.
Ocean Acidification: Long-term decrease in seawater pH from CO2 uptake.
OECM (Other Effective Area-Based Conservation Measure): Non-MPA areas delivering conservation outcomes.
Oil Spill Contingency Plan: Pre-arranged plan for spill response.
Oil Spill Modeling: Simulation of slick movement and weathering.
Oil Weathering: Processes such as evaporation, emulsification, and dispersion affecting spilled oil.
OSPAR Convention: Convention for the Protection of the Marine Environment of the North-East Atlantic.
Oxygen Demand (BOD/COD): Biochemical or chemical oxygen demand of effluent.

P

Particulate Organic Carbon (POC): Suspended organic carbon in seawater.
PCB: Polychlorinated biphenyl, persistent organic pollutant.
Pelagic Sargassum Influx: Massive Sargassum landings in the Caribbean and West Africa.
Persistent Organic Pollutant (POP): Long-lived bioaccumulative toxic substance regulated under the Stockholm Convention.
PFAS: Per- and polyfluoroalkyl substances, persistent chemicals of concern.
PFOS: Perfluorooctane sulfonate, a regulated PFAS.
Phthalate: Plasticizer additive of environmental concern.
Pinniped Haulout: Beach area where seals and sea lions rest, conservation focus.
Plastisphere: Microbial communities colonizing plastic debris.
Plume Modeling: Simulation of pollutant plumes in water or air.
PNEC (Predicted No Effect Concentration): Threshold concentration below which no adverse effects are expected.
PRF (Port Reception Facility): Shore facility for ship-generated wastes under MARPOL.
Protected Species Observer (PSO): Person monitoring marine mammals during seismic or pile-driving operations.

Q

Quaternary Pollutant: Quaternary ammonium compound in surfactants and biocides.
Quota Restoration: Conservation-driven adjustment to harvest quotas.

R

Ramsar Convention: International treaty for the conservation of wetlands of international importance.
Receiving Water: Water body into which discharges flow.
Recovery Plan: Strategy to restore listed species to viable populations.
Recovery Target: Population or habitat level required for delisting.
Reef-Friendly Sunscreen: Sunscreens excluding oxybenzone and similar compounds.
Reference Site: Relatively undisturbed location used for environmental comparison.
Regional Seas Programme: UNEP framework of regional seas conventions.
Resilience: Capacity of an ecosystem to absorb disturbance and recover.
Risk Quotient: Ratio of expected exposure to PNEC in risk assessment.

S

Sanctuary: Protected area for marine wildlife, such as US National Marine Sanctuaries.
Sargassum Belt: Pelagic Sargassum mat stretching across the tropical Atlantic.
Sediment Quality Guideline: Threshold for contaminants in sediments.
Sentinel Species: Species used to indicate environmental change.
Sewage Outfall: Discharge point for treated or untreated sewage.
Shipping Lane Shift: Rerouting to reduce risk of whale strikes.
Sink (Pollutant): Compartment where a pollutant accumulates.
SOLAS Environmental Impact: Indirect environmental aspects of SOLAS requirements.
Source Control: Reducing pollutants at their origin.
Source Inventory: List quantifying contributions of pollutant sources.
Spatial Planning (Marine): Process of allocating marine areas to uses to balance objectives.
Stranding Network: Coordinated responders to marine mammal strandings.
Subtidal Habitat: Habitat continuously submerged below low tide.
Sustainability Indicator: Metric tracking progress toward sustainability goals.

T

TBT (Tributyltin): Organotin biocide formerly used in antifouling, banned by AFS Convention.
Tier 1/2/3 Spill Response: IPIECA tiered response framework for oil spills.
Total Maximum Daily Load (TMDL): US regulatory limit on pollutant load to a water body.
Tourism Carrying Capacity: Maximum tourist load a coastal ecosystem can sustain.
Trace Metal: Metal present in low concentrations, sometimes bioessential or toxic.
Transboundary Pollution: Pollution crossing national boundaries.
Trash Wheel: Floating device collecting riverine litter before it reaches the sea.
Turtle Excluder Device (TED): Gear modification reducing sea turtle bycatch in trawls.

U

UN Decade of Ocean Science: 2021 to 2030 initiative led by IOC-UNESCO.
Underwater Noise: Anthropogenic acoustic energy affecting marine life.
UNEP: United Nations Environment Programme.
United Nations High Seas Treaty (BBNJ): 2023 agreement on marine biodiversity beyond national jurisdiction.
Urban Runoff: Stormwater carrying urban pollutants to coastal waters.

V

Vector (Invasive): Pathway by which invasive species are transported.
Vessel Strike: Collision between a ship and marine animal, usually a large whale.
VOCs (Marine): Volatile organic compounds emitted from oil cargoes and operations.

W

Wastewater Treatment Plant Effluent: Treated discharge from sewage works.
Water Framework Directive (WFD): EU directive establishing integrated river basin and coastal water management.
WCMC: World Conservation Monitoring Centre, UNEP biodiversity data center.
Wetland: Land area saturated with water seasonally or permanently, including coastal wetlands.

X

Xenoestrogen: Synthetic compound mimicking estrogen, environmental endocrine disruptor.
Xylene Marine Contamination: Aromatic hydrocarbon studied in coastal contamination.

Y

Yield per Recruit: Fishery model output relevant to bycatch and conservation analyses.
Young of the Year: First-year fish cohort, important to recruitment monitoring.

Z

Zero Discharge: Operational standard prohibiting discharges of certain wastes.
Zonation (Reef): Distinct biological zones across reef profile.
Zooxanthellae: Symbiotic dinoflagellates living in coral tissues.

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