WeatherTalk: Green icebergs are keeping us healthy – INFORUM

WeatherTalk: Green icebergs are keeping us healthy – INFORUM

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FARGO – Sometimes in winter, when the sun strikes a snowdrift at just the right angle, the snow appears blue. A glacier or an iceberg will appear distinctly blue in sunlight. This is a result of pure ice absorbing more of the red end of the visible spectrum of light and reflecting more of the violet end. Human eyes are more sensitive to blue light than violet, so we see these things as blue. Travelers to Antarctica, however, have noticed that some Antarctic icebergs appear more green than blue.
The assumption has always been this was somehow due to dead marine life somehow getting trapped and frozen into the underside of the ice. A recent study in the Journal of Geophysical Research has revealed the actual cause is likely iron oxides from Antarctic rock dust. This iron is an important nutrient for phytoplankton, which is a fundamental element of the world’s food chain, and it seems Antarctic icebergs deliver much of this iron.

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