As white light travels through water it is not only refracted and scattered, it is absorbed or 'attenuated' by the water. Varying wavelengths, or colours, are absorbed at differing depths; organic matter also adding to this absoption.
If water absorbs light wavelengths at differing depths, giving the appearance of either a green or blue topography, would a shadow created at the surface still be visible at depth as long as there is light? Is a shadow in effect a Faraday cage for visible light, creating a negative space or an absence, a 'border' through which this type of electromagnetic energy cannot pass?
