Glossary of Marine Terms

Abyssal Plain: A flat, deep-sea floor area found at depths between 3,000 and 6,000 meters.

Algae: Simple, plant-like organisms that live in water and can perform photosynthesis.

Atoll: A ring-shaped coral reef, island, or series of islets surrounding a lagoon.

Benthic Zone: The ecological region at the lowest level of a body of water, including the sediment surface and sub-surface layers.

Brackish Water: Water that has more salinity than freshwater but less than seawater, often found in estuaries.

Coral Bleaching: The loss of color in corals due to stress factors like increased water temperature, leading to the expulsion of symbiotic algae.

Echinoderms: A group of marine animals that includes starfish, sea urchins, and sand dollars, characterized by radial symmetry.

Estuary: A coastal area where freshwater from rivers and streams meets and mixes with saltwater from the ocean.

Hydrothermal Vent: An opening in the sea floor from which heated, mineral-rich water flows, often supporting unique ecosystems.

Intertidal Zone: The area between the high tide and low tide marks, where organisms must adapt to changing water levels.

​Mangrove: Coastal trees and shrubs that grow in saline or brackish water, providing important habitat for marine life.

Nekton: Aquatic animals that can swim and move independently of water currents, such as fish, squid, and marine mammals.
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Ocean Acidity: the level of acidity in the ocean, which is determined by the concentration of hydrogen ions (H+) in seawater

Pelagic: Pelagic fish are species that live in the open water column away from the sea floor and the shore. They have streamlined bodies for efficient swimming and often migrate long distances. (examples: tuna, mackerel, sharks, marlin, anchovies, herring).

Phytoplankton: Microscopic, photosynthetic organisms that form the base of the marine food web.

Plankton: Small and microscopic organisms drifting or floating in the sea or freshwater, including phytoplankton and zooplankton.

Polyps: Small, cylindrical, sessile organisms that make up coral colonies.

Salinity: The concentration of dissolved salts in water, usually measured in parts per thousand (ppt).

Seagrass: Flowering plants that grow in shallow marine environments, providing habitat and food for marine life.

Tide: The periodic rise and fall of sea levels caused by the gravitational forces of the moon and the sun.

Upwelling: The process by which deep, nutrient-rich water rises to the surface, supporting high primary productivity.

​Zooplankton: Microscopic animals that drift in the water column and feed on phytoplankton.