Blue The wavelength range of each hue in the spectrum is different. Colors in the center of the visible spectrum (yellow, green, and blue) penetrate the deepest into saltwater, whereas colors with longer (violet) and shorter (red and orange) wavelengths are absorbed and dispersed more quickly.
Why does this matter? Because if you want to see what's happening under the surface, then looking at the colored bubbles coming out of your tap is a good way to do it. The color of the bubble is mostly determined by the amount of oxygen present in the water. If there's less oxygen, then the water turns red due to the presence of iron. For some reason, blue bubbles are also common in low-oxygen conditions.
The color of seawater is usually described as either clear or cloudy. Clear water contains no solid particles to scatter light, so all the sun's rays can reach the bottom during daylight hours. At night, any particles that are suspended in the water column will glow from the sunlight that passes through them. This is why coastal waters tend to be more transparent at night than inland waters with their many trees and other objects that scatter light.
Cloudy water contains small particles such as clay or silt. During daylight these particles reflect light back up toward the surface, causing visual transparency to decrease. At night time these particles emit their own light, allowing visibility to increase again.
Yellow, green, and blue light wavelengths are capable of penetrating the ocean's depths. Other wavelengths cannot be observed because they are not present in the deep water. Blue and purple are the most visible colors at great distances.
The reason yellow, green, and blue can be seen from greater distances is because they are reflected by other particles in the water: algae and plankton. Algae and plankton live in the water column and get their energy from sunlight. So when it is sunny out and there is no cloud cover, lots of yellow, green, and blue shows up because that is what we see when there is more sun than clouds.
Plankton includes small plants and animals that drift through the oceans, lakes, and rivers. Plankton plays an important role in removing carbon dioxide from the atmosphere and storing it for future use by organisms when they grow or sink to the bottom of a body of water. As they break down, nutrients are released and help fertilize near-shore areas where phytoplankton would not normally survive. Yellow, green, and blue colored plankton can be seen from far away because these particles reflect light of all colors except red which is absorbed by chlorophyll molecules. Red is also used by some bacteria as a signal to protect themselves from harmful chemicals by changing coloration.
Because blue penetrates the deepest, deep, clear ocean water and certain tropical water seem blue most of the time. Furthermore, cleaner water has less particles that interfere with light transmission, and color is controlled by scattering by the water itself. Finally, red algae produces compounds that give water an orange-red color when it's in large quantities.
In conclusion, deep ocean water appears blue due to light being scattered by liquid particles rather than by any kind of dye present in the water itself.
The water works as a filter for sunlight. Because water absorbs colors in the red region of the light spectrum, the ocean is blue. This, like a filter, leaves colors in the blue portion of the light spectrum for us to view. Colors beyond red that are absorbed by water include orange, yellow, green, and violet.
Another reason why water is blue is because it's made up of molecules called hemoglobin that have spectral lines in the blue part of the spectrum. These lines come from molecules within the blood itself so they're not visible to the human eye. When sunlight hits water, it is filtered through this process so only certain wavelengths of light reach the bottom of the ocean. Those that don't get down there can't cause any damage so there's no need for fish to protect themselves against them.
Finally, blue lights can be used as a source of illumination since they're not absorbed by water. This means that lamps that emit such lights can be used in places where there is no access to electricity.
There you have it: the reason why water is blue is because it filters out colors beyond red which cannot do any harm so there's no need for fish to protect themselves against these waves. Also, lamps that emit such waves can be used for illumination since they won't disturb those who aren't aware of their existence.