The horizontal axis is the light wavelength, in nanometers, and the vertical axis is depth, in meters, at which the intensity of that wavelength is equal to one percent of the intensity at the surface. It is clear from this graph that wavelengths between approximately 370 and 500nm best penetrate into the depth. In other words, violet and blue parts of the spectrum penetrate best into seawater, whereas green light is much worse at that, yellow-orange is even worse, and red light with wavelengths longer than 600nm is only capable of penetrating very shallow waters.
significa che la radiazione a 350nm diventa l'1% solo dopo 100m di profonditā...
La 660nm č 1% dopo 9 metri circa... non proprio la stessa cosa in effetti...
------------------------------------------------------------------------
Light spectral distribution vs. wavelength on the surface (light blue), at 5m (blue) and 15m (dark blue) depths