Why Are So Many Deep Sea Creatures Red?
Red light does not reach ocean depths, so deep-sea animals that are red actually appear black and thus are less visible to predators and prey.
As you travel from surface waters to deeper waters, the quantity of light changes; it decreases with depth. The quality of light also varies with depth. Sunlight contains all of the colors of our visible spectrum (red, orange, yellow, green, blue, and violet). These colors combined together appear white.
Red light has the longest wavelength and, therefore, the least amount of energy in the visible spectrum. Wavelength decreases and energy increases as you move from red to violet light across the spectrum in the following order: red, orange, yellow, green, blue, and violet…
(read more: NOAA Ocean Explorer)
Image: The deep-sea scyphozoan jellyfish, Atolla wyvillei, as seen under white light. Image courtesy of Edith A. Widder, Operation Deep Scope 2005 Exploration, NOAA-OE.