Seaweeds near the ocean surface absorb most light colors, often appearing black. In shallower waters, they absorb red and blue light, resulting in green or black hues. Deeper water seaweeds, absorbing green light, tend towards red.

Types of algae like green, brown, and red algae are named for their colors, but their actual coloration varies with depth. Surface seaweeds adapt to absorb red and blue light, leading to green or black shades. Deeper seaweeds absorb blue-green light, appearing red or brown.