What condition causes certain colors to diminish as dive depth increases?

As a diver descends, they encounter increasing pressure and a denser environment, which affects how light behaves underwater. The correct answer, absorption, refers to the process where light waves are absorbed by water and its constituents, such as particles and dissolved substances.

Different colors of light have varying wavelengths, with red being the longest and blue being the shortest. As depth increases, water absorbs colors based on their wavelengths, with red light being absorbed first, followed by orange, yellow, and so on, until at deeper depths, blue and green wavelengths dominate. This phenomenon is key to understanding underwater visibility and the appearance of marine life, which may appear differently at varying depths due to the absorption of certain colors.

While diffraction involves the bending of light waves around obstacles, refraction refers to the bending of light as it passes from one medium to another, and reflection is the bouncing back of light from a surface, these phenomena do not contribute directly to the diminishing of color with depth in the same way that absorption does. Therefore, absorption is the most accurate explanation for why certain colors fade as a diver goes deeper into the water.