Although the Earth’s been decidedly blue for 600 million years, rising populations of phytoplankton caused by rising temperatures are once again causing the world’s oceans to turn green.

Billions of years ago, our planet did not have the deep blue oceans we admire today. Instead, they were actually […] ...

but reflect back green wavelengths more than blue. Certain types of phytoplankton even produce toxins that color the water red, a so-called "red tide." Other parts of the ocean may appear to have ...

Their simulation showed the iron was triple-charged, which meant it would have given the ocean water a green hue because iron hydroxide absorbs blue light and water absorbs red light—leaving ...

However, the ocean and its accompanying blue economy are actively being threatened by climate change, and problems will only worsen without proper government efforts. The ocean may also be key to ...