Seabed
The seabed is the bottom of a sea or ocean, including its sediments, exposed rock, and other materials. Its depths, terrain, and habitats vary widely.
Marine sediment: Particles and biological remains that settle and accumulate on the floor of seas and oceans. These deposits cover much of the seabed and preserve records of ocean conditions.
Seafloor spreading: The formation of new oceanic crust as magma rises at a mid-ocean ridge and moves outward. It continually creates seabed along spreading ridges.
Multibeam echosounder: A sonar instrument that measures depth across a wide swath beneath a vessel. It produces detailed maps of seabed relief.
Benthic zone: The ecological region at the bottom of a body of water, including its surface and subsurface. It frames the seabed as a habitat rather than only a physical surface.
Continental shelf: The submerged, gently sloping extension of a continent, from the shoreline to the continental slope. This broad, relatively shallow seabed borders continents.
Plate tectonics: The theory that Earth’s outer shell is divided into moving plates that interact at their boundaries. Its moving plates create, deform, and recycle large regions of seabed.
Side-scan sonar: A sonar system that images seabed texture and objects by recording reflected sound. It helps identify seabed features, wrecks, and hazards.
Benthic organism: An organism that lives on, in, or near the bottom of an aquatic environment. These organisms inhabit seabed surfaces and sediments.
Continental slope: The steep region connecting a continental shelf to the deeper ocean floor. It marks the transition from the shallow seabed to deep basins.
Subduction: The process in which one tectonic plate sinks beneath another into Earth’s mantle. It carries oceanic seabed downward and forms deep trenches.