Why are some icebergs green in Antarctica? Researchers think they've solved century-old mystery

Fox News | 3/5/2019 | Jennifer Earl
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The stunning sight of emerald green-colored icebergs in Antarctica has been documented for more than a century — in literature and beyond.

For decades, scientists have argued about the cause behind the bizarre phenomenon and debated why the green-hued ice chunks aren't the typical blue or white color. But a recent discovery from a 2016 research trip to East Antarctica’s Amery Ice Shelf may provide the final clue they've been waiting for.

Study - Journal - Geophysical - Research - Oceans

In a new study published in the Journal of Geophysical Research: Oceans, researchers found marine ice varies in color due to the "abundance of foreign constituents in the seawater," particularly iron-oxide materials. They came to this conclusion after scientists detected "large concentrations of iron" in the Amery Ice Shelf.

"Previously, dissolved organic carbon (DOC) had been proposed to be responsible for the green color," authors Stephen Warren, Collin Roesler, Richard Brandt and Mark Curran explained in the paper. "Subsequent measurements of low DOC values in green icebergs, together with the recent finding of large concentrations of iron in marine ice from the Amery Ice Shelf, suggest that the color of green icebergs is caused more by iron‐oxide minerals than by DOC."

Icebergs - Bubbles - Particles - Light

Icebergs are typically blue or white because they contain ice bubbles and snow particles that bend and scatter light.

Warren, a professor at the University of Washington and glaciologist who has been studying green icebergs for decades, said researchers used to believe seawater freezing onto the base of icebergs — combined with the icebergs' already blueish shade — contributed to the green color.

Minerals

But they have since concluded that iron-oxide rich minerals, also referred...
(Excerpt) Read more at: Fox News
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