Antarctica is the last unknown on Earth. The site of the South Pole ice desert apparently home only to penguins and thousands of scientists attempting to crack its many mysteries. But the riddle of one of Antarctica’s most bizarre phenomena – its green icebergs – has finally been explained.
Antarctic explorers have spotted strange green icebergs for centuries and scientists now believe they have cracked the green-hued mystery.
The green colour is caused by iron oxides in rock dust from Antarctica’s mainland.
Scientists collected the core data during a 2016 voyage to East Antarctica’s Amery Ice Shelf.
Significant quantities of iron were discovered buried in the Antarctic ice and theorised iron-oxide, can alter its colour.
The study’s authors concluded in the report: “Previously, dissolved organic carbon had been proposed to be responsible for the green colour.
“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 colour of green icebergs is caused more by iron‐oxide minerals than by dissolved organic carbon.”
Icebergs that form from glacier ice that breaks off from the Antarctic ice sheet is partially made-up of frozen seawater collected at the glaciers’ bases.
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 green ice at the bottom of the icebergs becomes visible when these icy chunks capsize.
Professor Stephen Warren, the study’s lead author, is a glaciologist at the University of Washington who has been studying green icebergs since 1988.
In his report, he recalled an oceanographer who tested an ice core from Amery Ice Shelf and found marine ice near the bottom of the core contained almost 500 times more iron than the glacial ice above.
Professor Warren believed the iron oxides were what was changing the marine ice from blue to green.
The phenomenon in not only noteworthy because of its eye-catching beauty.
Marine ice contains iron carried by these glaciers, which could help feed organisms as they float deeper into the ocean.
Professor Warren said: “It is like taking a package to the post office.
“The iceberg can deliver this iron out into the ocean far away, and then melt and deliver it to the phytoplankton that can use it as a nutrient.”