Near the Bahama Islands, the lighter aqua colors are shallow water where the sunlight is reflecting off of the sand and reefs near the surface. Left Image: Phytoplankton are very small, single-celled plants, generally smaller than the size of a pinhead that contain a green pigment called chlorophyll. All plants on land and in the ocean use chlorophyll to capture energy from the sun and through the process known as photosynthesis convert water and carbon dioxide into new plant material and oxygen.
Right Image: Although microscopic, phytoplankton can bloom in such large numbers that they can change the color of the ocean to such a degree that we can measure that change from space. The swirls of green are a phytoplankton bloom in the Gulf of California. Changes in ocean color can be caused by a variety of sources.
In this SeaWiFS image, two currents are flowing past each other. The warm Brazil Current flows south next to the shore of Argentina. The Falkland Islands can be seen at the bottom of the image. The interaction of these two currents brings nutrient-rich water from the deep ocean to the surface, providing an excellent environment for the growth of phytoplankton.
The distinct populations of phytoplankton in each current can be perceived as different colors. Recommended Articles. September 28, September 08, May 10, Episode 31 - Connected By Earth. April 28, Gross then asks, "So why are sunsets orange? Perhaps the most helpful response came from Michael Kruger of the department of physics at the University of Missouri. He sent the following reaction:. The sky is blue not because the atmosphere absorbs the other colors, but because the atmosphere tends to scatter shorter wavelength blue light to a greater extent than longer wavelength red light.
Blue light from the sun is scattered every which way, much more so than the other colors, so when you look up at the daytime sky you see blue no matter where you look. This scattering is called 'Rayleigh scattering'; the amount of scattering goes as the frequency of the light to the 4th power. By the way, this effect is most prevalent when the particles that do the scattering are smaller than the wavelength of light, as is the case for the nitrogen and oxygen molecules in the atmosphere.
When the sun is setting, the light that reaches you has had to go through lots more atmosphere than when the sun is overhead, hence the only color light that is not scattered away is the long wavelength light, the red. In this region, off the coast of Easter Island in the southeast Pacific Ocean , the water is deep and remarkably clear due to its location in the middle of a giant oceanic gyre, or large circular current. Its central location means there is minimal mixing of ocean layers and nutrients aren't pushed up from the deep bottom.
The purity of the water here, coupled with its depth make the ocean here appear a deeper indigo than perhaps anywhere else. A species of bacteria called Synechococcus cyanobacteria has the ability to adjust its color to match different wavelengths of light across the world's oceans. These bacteria harness light to capture carbon dioxide from the air and produce energy. As research published Feb. Sign up for our Newsletter! Mobile Newsletter banner close. Mobile Newsletter chat close.
Mobile Newsletter chat dots. Mobile Newsletter chat avatar. Mobile Newsletter chat subscribe. Environmental Science. Earth Science. Along with nutrients from the volcanic island soils and runoff of seabird and seal guano from rain, we see high chlorophyll and phytoplankton concentrations, which tint the water green in places.
Because the absorption that gives water its color is in the red end of the visible spectrum, one sees blue, the complementary color of orange, when observing light that has passed through several meters of water.
Snow and ice has the same intense blue color, scattered back from deep holes in fresh snow. 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.
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