In coastal locations, after mixing events have occurred, the ocean at times reorganizes itself into thin layers, by means of processes that are still under investigation. Thin layers may vary from a few 10's of centimeters to a meter or so in vertical extent. These layers were discovered when optical equipment became accurate enough and could sample rapidly enough to distinguish these layers.

The original optical equipment used in these discoveries were manufactured by WET Labs. Thin layers have distinct optical, biological, chemical, physical, and acoustical signatures. They may have optical properties such as absorption coefficients that are orders of magnitude larger than in the layers just above or below. This is because thin layers of phytoplankton or zooplankton may contain densities of organisms ranging up to 1000 times those found just above, or below the structure. These extraordinary concentrations of living material have important implications for many aspects of marine ecology (e.g. phytoplankton growth dynamics, micro- and macro-zooplankton grazing, behavior, life histories, predation, and harmful algal blooms), as well as for ocean optics and acoustics.

See the ORCAS poster for more details about thin layers.

  An excellent web site to learn more about thin layers is Univ. of Rhode Island's Thin Layers Program.

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