Light Attenuation for Various Wavelenghts of Color in Water

Below is a chart that shows the attenuation of different wavelenghts of light in water. The numbers were calculated using Windows Excel by using the equation:

Z=ln(Iz/Io)/-K

     where:
Z= Depth (meters)
Iz= intensity of the light at a depth of Z meters
Io= Intensity of the light at the surface

K= Attenuation coefficient (meters^-1)

The values start at 1% or 0.01 because you cannot take the natural log of zero, and also because 1% light attenuation is the point where all benefit from photosynthesis is used for respiration. Each K value is specific for each color.



Figure One.  Table of Light Attenuation.



Figure Two.  Graph of Iz/Io Vs. Z.