Instead of reflecting blue light, they may have been glowing green due to iron-rich waters. During this time, the oceans contained large amounts of iron hydroxide.

Nearly three fourths of Earth is covered by oceans, making the planet look like a pale blue dot from space. But Japanese researchers have made a compelling case that Earth's oceans were once green ...

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.

Blue-green algae, also called cyanobacteria, were one of the earliest life forms on Earth and contributed heavily to the oxygenation of the planet.

From the iron-rich green waters of ancient Earth to the blue oceans of today, the planet’s color has reflected its ever-changing environment. Now, scientists are watching closely.

That, in turn, meant that those particles absorbed blue and red light, when meant that more green light was able to pass through and the oceans appeared green.

Nearly three fourths of Earth is covered by oceans, making the planet look like a pale blue dot from space. But Japanese researchers have made a compelling case that Earth’s oceans were once ...

Earth’s oceans used to be green, and they could turn purple next By Jay Kakade April 27, 2025 What I think purple oceans might look like, generated with AI ...

Forests are now absorbing more carbon than oceans, according to satellite data - revealing a major shift in Earth's ...