Icebergs appear blue and white when they float on seawater. This is due to the fact that ice draws in more red light than blue light. Since the beginning of the 1900’s, sailors and explorers, when out in the sea, have reported seeing various green icebergs in Antarctica. One can tell these icebergs apart quickly since they have a strong green color. Its ice usually has a darker emerald hue making it clearer than regular ones.
You might be wondering what causes this unusual color? Researchers found their first explanation when glaciologists collected samples from a green iceberg in 1988. These samples belonged to the amery ice shelf. What they found was quite fascinating. Green sharpened ice was different from a normal iceberg ice since icebergs become detached from glaciers and ice shelves that flow into the sea. These glaciers ice form when huge amounts of snow build on top and solidify. Naturally, this creates air pockets that reflect light. In Antarctica it is different because icebergs have a different type of ice layer on top of them. It is called marine ice. Marine ice is clearer and darker than glacier ice because it does not have air pockets to reflect light.
From here scientists implemented that the water beneath the amery ice shelf was turning the ice green. So in 2016 they decided to test an ice core, from this location, for its iron content. The core at the bottom of the sea had 500 times more iron than the glacial ice high above. Iron oxides in the marine ice was turning the icebergs green. The last question they needed to solve was where the iron came from. It came from land. As glaciers flow and make their way through bedrock, they grind rocks into a thin powder.(glacial flour). The combination of iron oxides and glacial flour are the reason for the green color. As scientists still have many questions to answer about these amazing colored icebergs, they are looking for the positive functions they might have. Between these, the importance of them to sustain ocean life.
