The relationship between light and water is one of the most dynamic and complex in all of nature. The shimmering, shifting, rapidly changing patterns we see as shafts of light penetrate the deep, or create kaleidoscopes of colour and pattern on a reef or sandy sea bed are the visual cues of this relationship.

The surface of any body of water is a flexing, bulging, folding boundary which dramatically changes the nature and structure of the light rays from the sun and moon. Some light bounces right off the surface, reflected back into the air and has no impact on what lies below the surface, while some passes through where it provides the energy required to drive the most fundamental and critical biological processes that all life on the planet depends on.

But water does not yield to light without a fight! The dense, moving mass of lake, ocean or river refracts and distorts light, and quickly strips away large chunks of the visible spectrum, leaving an ever increasing percentage, but diminishing amount, of short wave-length blue-to-violet light. Eventually, this too is stripped away, absorbed or reflected back, to create the light-less black of the deep ocean abyss.

In aquaculture, public aquaria and aquatics in general, light plays a critical role.