Marine Biology Glossary

Vast, flat areas of the deep ocean floor, typically between 3,000 and 6,000 meters depth, covered in fine sediment.

A rapid increase in the population of algae in an aquatic system, often caused by nutrient pollution, which can deplete oxygen and produce toxins.

Relating to the bottom of a body of water or the organisms that live on or in the seafloor sediment.

The variety and variability of life forms within a given ecosystem, biome, or the entire planet, including genetic, species, and ecosystem diversity.

The increasing concentration of a substance, such as a toxin or pollutant, in the tissues of organisms at successively higher levels in a food chain.

The incidental capture of non-target species during commercial fishing operations, including marine mammals, sea turtles, and seabirds.

The biological production of organic molecules using energy from chemical reactions with inorganic compounds rather than sunlight.

The extended perimeter of a continent submerged under relatively shallow ocean water, typically less than 200 meters deep, supporting rich marine life.

A hypoxic area in a body of water where dissolved oxygen is too low to support most marine life, often caused by eutrophication.

Relating to organisms that live near or on the bottom of the sea, such as flatfish, crabs, and lobsters.

A partially enclosed coastal body of water where freshwater from rivers meets and mixes with saltwater from the ocean, creating a unique brackish environment.

The excessive enrichment of a water body with nutrients, especially nitrogen and phosphorus, leading to dense plant and algal growth and oxygen depletion.

A large system of circular ocean currents formed by global wind patterns and the Coriolis effect, which can accumulate floating debris like plastic.

A fissure on the seafloor from which geothermally heated water discharges, supporting unique chemosynthetic ecosystems in the deep ocean.

The area of the shore between the high-tide and low-tide marks, subject to alternating periods of submersion and exposure to air.

Underwater ecosystems formed by dense growths of large brown algae (kelp) that provide habitat, food, and shelter for a diverse community of marine organisms.

A salt-tolerant tree or shrub that grows in coastal intertidal zones of tropical and subtropical regions, forming important nursery habitats.

The ocean zone from 200 to 1,000 meters depth, also called the twilight zone, where light is too dim for photosynthesis but some light is visible.

Plastic particles smaller than 5 millimeters that pervade marine environments and are ingested by organisms at all trophic levels.

An environment that provides food, shelter, and protection for juvenile marine organisms during critical early life stages.

Relating to the open water column of the ocean, as opposed to the seafloor (benthic) or the coast (littoral).

Microscopic photosynthetic organisms that drift in the sunlit upper layers of the ocean, forming the base of most marine food webs.

The concentration of dissolved salts in water, typically measured in parts per thousand, which influences water density and organism distribution.

The process by which deep, cold, nutrient-rich water is brought to the ocean surface, typically by wind-driven currents, boosting primary productivity.

Small drifting animals and larvae in the ocean that feed on phytoplankton and are consumed by larger organisms, forming a critical link in marine food webs.