Scientists solve the mystery of rare GREEN icebergs seen only in Antarctica

Rodiano Bonacci
Marzo 8, 2019

When the blue glacier ice mixed with the yellow marine ice, theory hypothesized, a green color would be produced.

"The marine‐ice part of such icebergs is clear, dark, and often green in color, because red or yellow particles from the seawater, in combination with the blue of ice, can shift the color to green", the researchers further explained.

A brand new study claims that the green color is the result of the iron oxides in the rock dust from Antarctica's mainland. They formulated the brand new principle after Australian researchers found massive quantities of iron in East Antarctica's Amery Ice Shelf. These compounds are scarce in many regions of the ocean.

"It is like taking a package deal to the submit workplace".

Now Stephen Warren, a glaciologist at the University of Washington, and his colleagues may have finally solved the mystery.

Since we associate ice with the white colour, it seems obvious to think that icebergs are going to be all that way, of a pristine white.

"When we climbed up on that iceberg, the most fantastic thing was actually not the color but rather the clarity", Warren said.

This frozen sea water contains organic and inorganic particles that add hues of green to ice that normally comes in shades of blue or white. The centre of the picture shows the clear, dark green, bubble-free marine ice.

The green ice at the bottom of the icebergs becomes visible when these icy chunks capsize.

For decades, scientists have argued about the cause behind the freakish phenomenon and debated why the green-hued ice chunks aren't the typical blue or white color. When the ice meets the sea, this glacial flour flows into the ocean where it can get trapped in marine ice. An oceanographer from the University of Tasmania discovered that the marine ice at the bottom of the Amery Ice Shelf has 500 times more iron than the glacier ice at the top.

The emerald ice, however, has no bubbles, suggesting it was not ordinary glacier ice. Dissolved organic carbon is yellow, so if pure ice is blue, the addition of yellow particles could turn the ice green, according to Warren. "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".

When an oceanographer testing an ice core from Amery Ice Shelf found marine ice near the bottom of the core had almost 500 times more iron than the glacial ice above, Warren began to suspect iron oxides in the marine ice could be turning blue ice green.

Ted Scambos, a senior research scientist at the National Snow and Ice Data Center who did not contribute to the research, told Mashable the explanation makes "perfect sense".

The Daily Mail writes that Scientists discovered large amounts of iron in the polar ice and theorized that "foreign constituents" in seawater, particularly iron-oxide, can change its color.

Warren believes iron oxides in "glacial flour", a powder created when glaciers grind against bedrock, from rocks on Antarctica's mainland are responsible for creating the stunning emerald icebergs. Pure ice, in fact, is blue, because it absorbs more red light and reflects blue light.

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