In response to yesterday’s review of Aquaman Volume 1: The Trench, Al Dove made a simple request via twitter:

This question is more complex than it first appears, and needs a little unpacking. Water is denser than air. When light passes through, the water acts as a filter, absorbing visible light in a predictable pattern from longest wavelengths (infrareds and reds) to shortest wavelengths (purples and ultraviolets). As Aquaman dives deeper, the brilliant colors of his orange and green costume will begin to fade.

At around 5 meters, reds will begin to blend in with the oranges. This is less a problem for Aquaman than it is for Mera, his red-headed companion. At 10 meters, his orange shirt will appear dull yellow, blending in with his golden accessories. 20 meters down, the yellows will fade away, leaving Aquaman in what would appear to be a hazy green wetsuit. Passed 30 meters, even the greens are gone. Diving deeper, or hero will slowly fade into the vast blue expanse until, beyond 100 meters, practically all light is gone.

This phenomenon has several fascinating implications for ocean life. When you look at the brightly colored patterns of a tropical reef fish, try to think of how those patterns translate as the fish travels underwater. Perhaps those magnificent stripes are less about showing off and more about breaking up the fish’s profile–an evolutionary gillie suit–that allows them to adapt effortlessly to different predators at different depths?

Because red is the first color to go, many marine organisms, especially crustaceans, cannot see red light. They lack the ability to detect it in the same way that we can’t see ultraviolet or infrared light. This is good news for aspiring behavioral ecologists, as it allows us to study nocturnal rhythms without disturbing the organisms. Leatherback sea turtles don’t respond to red light, either, which is why you’ll see patrolers on nesting beaches carrying red flashlights. Many deep-sea species are also red, rendering them completely invisible to all but the craftiest predators.

Speaking of crafty predators, when you see something like a dragonfish that use red bioluminescent photophores to hunt its prey, you should think “deep sea ninja”. While the dragon fish can use the light to see prey that is very close by, the prey will not be able to see its predator.

This also means that the menacing red glow of the Black Manta’s dive helmet is not there to strike terror into his enemies, but to allow Aquaman’s deadliest foe to stalk his rival, undetected, through the deepest seas.

This, incidentally, is why you can’t get wifi while SCUBA diving, but you can get a sunburn.