deep scattering layer
–noun Oceanography. | a zone of biological origin within the ocean, at a depth of 900–1200 ft. (270–360 m), which scatters sounding echoes. |
Also called scattering layer.
scattering layer
n. A concentrated layer of organisms in the ocean that reflects and scatters sound waves, as from sonar. |
The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2009 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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scattering layer
A concentrated layer of marine organisms found in most oceanic waters that reflects and scatters sound waves, as from sonar. The layer is of varying composition and can include both plankton and nekton (free-swimming organisms such as copepods, krill, and small fish). Scattering layers, which may occur at more than one depth in the same location, typically move upward at night to feed on phytoplankton and downward during the day, as deep as 1,000 m (3,280 ft), probably to escape predators. Also called deep scattering layer.
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The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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