Ocean science news, explainers, and statistics covering marine environments, currents, climate, coasts, seafloor research, and the changing global ocean.
Wind waves are being generated by the wind where they are observed, while swell has traveled away from the weather that created it. Local wind waves are usually shorter and steeper, with less orderly crests. Swell commonly arrives as longer, smoother crests with a steadier direction. A single stretch of ocean can carry both at…
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Calcareous ooze is deep-sea sediment dominated by calcium carbonate remains, chiefly from microscopic organisms such as foraminifera and coccolithophores. Siliceous ooze is dominated by silica remains from diatoms or radiolarians. Their distributions record plankton productivity, water chemistry, depth and the supply of sediment from land. Marine geologists commonly apply the word ooze when biogenic remains…
Sonar backscatter measures the strength of sound that returns to a receiver after striking the seafloor or an object in the water. Strong and weak returns form an acoustic image of bottom character. The data can help distinguish exposed rock from soft sediment, trace lava flows and identify wrecks, although echo strength never identifies a…
Multibeam sonar measures the depth and three-dimensional form of the seafloor across a wide swath. Side-scan sonar records detailed acoustic imagery that is especially useful for finding objects and changes in bottom texture. Both transmit sound sideways beneath a survey vessel, but their main products answer different questions. A multibeam map tells a surveyor how…
