Water is colorless. Yet, bodies of water sometimes look colored. Rivers of fresh glacial melt often appear green, while Caribbean beach waters appear an alluring blue or blue-green, seemingly colored to attract tourists.
If water is indeed colorless, how is it that waters can sometimes appear colored?
Conventional explanations involve mineral content. Color is argued to arise from the presence of water-borne minerals, which supposedly confer color. This explanation may suffice in part, but the mineral supply cannot be infinite. Over time, the color should diminish, eventually disappearing. Yet, water color is not in short supply. It persists, seemingly indefinitely.
An alternative possibility is that the color comes from the presence of EZ water, which exhibits color by fluorescing1. The color appears when we expect EZ to appear, and EZ-fluorescence colors are the very ones that we witness.
Color often appears in rivers of fresh glacial melt water. When ice melts, it does not transition into liquid water directly; it melts into EZ water, which eventually converts to liquid water. Details of these transitions can be found in the book entitled The Fourth Phase of Water3, which goes on to explain how recognition of this feature transforms various anomalies of ice formation into straightforward expectations.
The main point here is that fresh ice melt contains ample EZ water2; and secondly, that EZ water fluoresces1. So, we can understand why rivers of fresh ice melt will often exhibit color. Downstream, as the EZ water converts to liquid water, the color will progressively vanish. So, the color shows when we expect the EZ to be present. In fact, the presence of color in the water may be an indicator of EZ presence.
Fluorescence color depends on the nature of the ambient light. The shorter the ambient wavelength, the shorter the fluorescence wavelength1. When short, ultraviolet wavelengths dominate the environment, the water will fluoresce at the shortest visible wavelength, i.e., violet. When incident sky blue dominates, the fluorescence will tend toward the blue-green, etc. So, while liquid water is colorless, EZ water can fluoresce different colors. And since the EZ distributes throughout the full extent of the water, the color appears to come from deep below, as though the entire volume of water is colored.
Much the same happens in tropical waters. There, environmental heat plays a dominant role.
Heat is tied closely to infrared energy. Infrared emission is commonly linked to the glowing heat of, say, an electric range. But infrared energy is emitted not only by those glowing coils but also by everything in our environment. To confirm that fact, merely turn off the lights, so nothing can be seen. Then, take an infrared camera, i.e., a camera sensitive to infrared wavelengths instead of visible wavelengths, and obtain an image. Even though it’s dark, virtually everything shows up. That means everything generates infrared energy.
Why is infrared energy important? Infrared is the very energy that builds EZ water3, Abundant IR means that the energy required for EZ buildup is ever present in the environment. The warmer the environment, the higher the infrared content. In tropical regions, therefore, infrared energy is present in abundance. Hence, tropical waters should contain more EZ than colder waters. With higher concentration of EZ, we anticipate more fluorescence, hence deeper color. So, rather consistently, tropical waters should be colored, as indeed they are.
Hence, liquid water indeed has no color. Nor does EZ water. However, EZ water does fluoresce, and that fluorescence is the likely source of the colors seen in various natural waters.
1 Chai, B, Zheng, JM, Zhao, Q, and Pollack, GH: Spectroscopic studies of solutes in aqueous solution. J. Phys. Chem., A 112 2242-2247, 2008.
2 So E, Stahlberg R, and Pollack GH: Exclusion zone as an intermediate between ice and water. in: Water and Society, ed. DW Pepper and CA Brebbia, WIT Press, pp 3-11, 2012.
3 Pollack, GH: The Fourth Phase of Water. Ebner and Sons 2008.