Editing Attenuation (section)

== Light attenuation in water ==
{{Main|Electromagnetic absorption by water}}
{{Further|Color of water|Ocean color}}

[[Shortwave radiation]] emitted from the Sun have wavelengths in the [[visible spectrum]] of light that range from 360&nbsp;nm (violet) to 750&nbsp;nm (red). When the Sun's radiation reaches the sea surface, the shortwave radiation is attenuated by the water, and the intensity of light decreases exponentially with water depth. The intensity of light at depth can be calculated using the [[Beer-Lambert Law]].

In clear mid-ocean waters, visible light is absorbed most strongly at the longest wavelengths. Thus, red, orange, and yellow wavelengths are totally absorbed at shallower depths, while blue and violet wavelengths reach deeper in the [[water column]]. Because the blue and violet wavelengths are absorbed least compared to the other wavelengths, open-ocean waters appear [[ocean color|deep blue]] to the eye.

Near the shore, coastal water contains more [[phytoplankton]] than the very clear mid-ocean waters. [[Chlorophyll]]-a pigments in the phytoplankton absorb light, and the plants themselves scatter light, making coastal waters less clear than mid-ocean waters. Chlorophyll-a absorbs light most strongly in the shortest wavelengths (blue and violet) of the visible spectrum. In coastal waters where high concentrations of phytoplankton occur, the green wavelength reaches the deepest in the water column and the [[color of water]] appears [[blue-green]] or [[Spring green#Sea green|green]].

{{anchor|Seismic attenuation}}