In a display of nature's palette, NASA has released satellite imagery capturing colorful icebergs near the Amery Ice Shelf in east Antarctica.
The vibrant blues, greens and even yellowish tones in the icebergs stand out against the white expanse of snow and sea ice, offering a rare glimpse of the region's dynamic ice features.
The image, taken on October 26 by the Operational Land Imager-2 (OLI-2) aboard Landsat 9, reveals flipped icebergs exposing their snow-free undersides. The colors result from the unique properties of glacial and marine ice.
Most icebergs appear white or bluish because of air bubbles in compressed glacial ice that scatter light. However, in some regions of the Amery Ice Shelf, seawater freezes onto the ice shelf's underside hundreds of meters below the surface.
This bubble-free marine ice reflects the impurities in the seawater, leading to a range of hues.
"The clear marine ice can vary in color from deep blue, to green, to even brownish yellow, depending upon the concentration of constituents in the sea water," Collin Roesler, an oceanographer at Bowdoin College, said in a statement.
Roesler's 2019 research revealed that some icebergs near the Amery Ice Shelf take on a jade-green hue because of iron oxides in seawater that originate from rock dust on the mainland.
Roesler's study highlighted the ecological significance of these icebergs. The iron-rich icebergs, formed in specific conditions under the Amery Ice Shelf, act as carriers of essential nutrients. As they drift and melt, they transport iron from the land to the sea.
These vibrant colors are visible only when icebergs overturn, a phenomenon triggered by melting or breaking that makes them unstable. Helicopter surveys in the area have revealed a high proportion of overturned icebergs, making this region particularly notable for its colorful ice displays.
"Our analysis suggested that the Amery Ice Shelf is particularly suited to forming green icebergs because of the conditions that support the accumulation of freezing seawater onto the underside of the shelf," Roesler said.
The images captured from space also revealed another fascinating Antarctic feature -- a large guano stain near Cape Darnley, evidence of an emperor penguin colony.
Jan Lieser, a meteorologist and sea ice scientist with the Antarctic Meteorological Service, noted the guano's visibility in satellite images, saying in a statement: "It's interesting that we can see their excrement from space."
The discovery aligns with past research in which scientists have used satellite imagery to locate remote penguin colonies by identifying guano stains.