Ocean science news, explainers, and statistics covering marine environments, currents, climate, coasts, seafloor research, and the changing global ocean.
The carbonate compensation depth, usually abbreviated CCD, is the ocean depth where the supply of calcium carbonate particles to the seafloor is balanced by their dissolution. Below the CCD, little carbonate accumulates in sediment because shells and skeletal fragments dissolve as fast as they arrive, or faster. The CCD is a chemical boundary rather than…
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A mid-ocean ridge is a continuous volcanic mountain system where tectonic plates separate and new oceanic crust forms. Its connected segments extend nearly 65,000 kilometers, or about 40,000 miles, through every ocean basin. Most of the range lies underwater, hidden beneath two or more kilometers of seawater. At a ridge, hot mantle rises as plates…
A seamount is an underwater mountain rising steeply from the seafloor, usually with a volcanic origin. A guyot is a seamount with a broad, flat summit. The flat top records a period when waves eroded the volcano near sea level before the crust beneath it cooled, subsided or otherwise carried it into deeper water. NOAA…
A submarine canyon is a steep-sided valley cut into the seafloor, usually across a continental shelf or slope. Some begin near a river mouth, while others start far offshore. Their channels can descend for kilometers and extend into the deep ocean, giving sediment, organic matter and water a direct route across the continental margin. Canyons…
