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The color of the ocean is changing–here’s why

By the end of the 21st century, the polar oceans may be tropical green, while other areas will shift to a dark blue. It’s another example of how climate change is altering our planet.

The color of the ocean is changing–here’s why
[Photo: Saffu/Unsplash]

The color of the oceans is changing. It’s not noticeable to the naked eye yet, but satellites are already picking up the shifting wavelengths. The culprit? Climate change. According to new research published this week in Nature, a newly developed computer model by a team of MIT scientists shows that increasingly warm water temperatures will alter the appearance of the oceans–and their model has been proven out by satellite images taken by NASA over the past few decades.

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It’s the latest example of how climate change will dramatically alter not just how the natural world works, but how it looks. Countless films, paintings, and photos, including famous Blue Marble photograph, captured by the crew of Apollo 17, will serve as a reminder of what our planet once looked like.

Oceans are the earth’s lungs, as well as its biggest temperature regulator, absorbing much of the increasing atmospheric heat. The latter process affects marine life at all levels, starting with the zillions of microorganisms floating in the our planet’s seas. Higher temperatures mean that some organisms will die in some geographical areas while, in others, the same organisms will bloom.

[Image: MIT/courtesy Nature Communications]
Those life changes will inevitably lead to a shift in hue because the oceans’ color is directly determined by substances and particles floating in the water, from the salt level to chlorophyll in algae and phytoplankton–which is the biggest factor in color. The different floating particles absorb or scatter the sunlight at different wavelengths, each type adding a different color to the water.

Logically, if you increase the amount of some of these components, the overall color will change too–just like the variation of pigments in oil paint change its color. The more phytoplankton, for example, the greener the water will be. You can see these changes through the seasons: as temperatures rise during the spring and summer in some parts of the world, the phytoplankton blooms, making the oceans greener. Witness this bloom in the North Atlantic around late May, as captured by NASA/NOAA satellites:

[Image: Jeff Schmaltz/MODIS Rapid Response Team/NASA]

According to the computer model developed by MIT scientists, this will make the water near the poles a weirdly strange tropical green, as phytoplankton invade these territories thanks to the higher temperature conditions ideal for their reproduction.

On the other hand, in other areas of the ocean where conditions are not conducive to life for these organisms, the color will be bluer because of the way that water molecules absorb sunlight. As the temperature increases over tolerable limits for phytoplankton and algae in the subtropical areas, microorganisms will inevitably die. And without these little critters, the water will “die” too, and the blues will turn bluer and darker.

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Not only will climate change have a definitive impact on nature, killing off countless species and thus affecting our own capacity to thrive. It will also indelibly change the appearance of our planet, of which 71% is covered by water. If we survive long enough to witness it, anyway.

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About the author

Jesus Diaz founded the new Sploid for Gawker Media after seven years working at Gizmodo, where he helmed the lost-in-a-bar iPhone 4 story. He's a creative director, screenwriter, and producer at The Magic Sauce and a contributing writer at Fast Company.

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