Why is tropical water blue

Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options. Go Paperless with Digital. He sent the following reaction: "The answer to why the sky is blue isn't quite correct. Get smart.

Sign up for our email newsletter. Sign Up. By: Amanda Onion Updated: May 13, Someone gazing out at the ocean from the Maine coast sees very different hues than someone squinting at the sea from a sunny beach on a Greek island. So why does the ocean come in so many shades of blue? The color of the ocean surface for the most part is based on depth, what's in it and what's below it.

A glass of water will, of course, appear clear as visible light passes through it with little to no obstruction. But if a body of water is deep enough that light isn't reflected off the bottom, it appears blue. Basic physics explains why: Light from the sun is made up of a spectrum of different wavelengths.

The longer wavelengths appear to our eyes as the reds and oranges, while the shorter ones appear blue and green. When the sun's light strikes the ocean, it interacts with water molecules and can be absorbed or scattered. If nothing is in the water except water molecules, light of shorter wavelengths is more likely to hit something and scatter, making the ocean appear blue.

The longer, red portions of sunlight, meanwhile, are absorbed near the surface. Depth and the ocean bottom also influence whether the surface appears a dusky dark blue, as in parts of the Atlantic, or casts a sapphire-like shimmer as in tropical locations. And then there's the fact that the ocean is rarely clear, but is instead teeming with tiny plant and animal life or filled with suspended sediment or contaminants.

Oceanographers monitor the ocean's color as doctors read the vital signs of their patients. Color seen on the ocean's surface reflect what's going on in its vast depths.

Blue water is the only known example of a natural color caused by vibrational transitions. In most other cases, color is caused by the interaction of photons of light with electrons. Some of these mechanisms are resonant interactions, such as absorption, emission, and selective reflection.

Others are non-resonant, including Rayleigh scattering, interference, diffraction, and refraction. Unlike with water, these mechanisms rely primarily on the interaction of photons with electrons. Nice science all around that tells me why water can look blue, but none answer the actual question — why is tropical water often turquoise and why is high latitude water almost never turquoise? I have been wondering this all my life, and I studied environmental science at the university of Alaska and never got an answer that satisfied me.

I have sailed around the world three times, seen many of the great diving spots, and mountaineered across many glaciers and high altitude lakes and streams and no one can say why the water is same turquoise in a snowy mountain stream NOT glacier fed, gold creek Juneau alaska or off the rocky coast of South Island New Zealand these are places where there is very little direct sunlight and even when looking at splashing water it is the same beautiful color as off the coast of Panama.

Though can anyone answer is this the same as the lighter, aqua-turquoise we see when a wave breaks… my emails is: [email protected] , If anyone can share the science behind the beauty of the aqua colour created at a wave break, I would sincerely appreciate it!

Save my name, email, and website in this browser for the next time I comment. This site uses Akismet to reduce spam. The Caribbean is such a light a shade of blue due to the tendency of the Caribbean coast to scatter sunlight.

The fact that the sand is light colored and the water is relatively shallow also makes the water appear turquoise. Another element that makes water appear blue is the absence of phytoplankton, or algae, which tend to proliferate in water and absorb green light, thereby making water look more green.

Surprisingly, for all of the above reasons, we as humans perceive Caribbean water as being significantly clearer than water anywhere else in the world.

This superior clarity has a lot to do with the tidal currents of the area. These currents prevent the layers of sediment usually found in other bodies of water from collecting at the bottom of territorial Caribbean waters, meaning that most of these waters do not have a deep oceanic floor. Providenciales is a smaller island in Turks and Caicos, and yet it has the highest concentration of sand bars in the Caribbean.

This means the island has an incredible amount of companies that offer different activities in water sports. And since Providenciales is a smaller island, it has fewer tourists and more space to accommodate them and their requirements.

Due to this factor, the water is much cleaner than it would be on a larger island. For more useful blogs, click here!