Where waters are “optically shallow,” the bottom reflects light and often can be seen by humans and satellites. Here, ocean optics can also be used to study what is under the water. Based on what color they appear to sensors, researchers can map habitat types, including macroalgae, corals, seagrass beds, and more. Mapping shallow-water environments requires knowledge of ocean optics because the color of the water must be accounted for when looking at the color of the seabed environment below.