From: National Centre for Biological Sciences
Published October 3, 2017 10:28 AM

Algae Growth Reduces Reflectivity, Enhances Greenland Ice Sheet Melting

New research shows algae growing on the Greenland ice sheet, the Earth’s second-largest ice sheet, significantly reduce the surface reflectivity of the ice sheet’s bare ice area and contribute more to its melting than dust or black carbon. The new findings could influence scientists’ understanding of ice sheet melting and projections of future sea level rise, according to the study’s authors.

Glaciologists have long known materials such as mineral dust and black carbon can darken the surface of large ice sheets. Scientists study these impurities because they reduce the sheet’s albedo, or the extent to which it reflects light, which increases melting of the ice and affects projections of sea level rise. But few studies had examined the darkening effect of algal cells, which naturally grow on the ice sheet.

The new study quantitatively assessed how surface ice algae contribute to darkening of the ice sheet, and found the algae reduce the ice sheet’s albedo significantly more than non-algal materials, like mineral particles and black carbon. Algal darkening is responsible for 5 percent to 10 percent of the total ice sheet melt each summer, according to the new research published in Geophysical Research Letters, a journal of the American Geophysical Union.

Continue reading at American Geophysical Union

Image: An aerial view of the study area on the Greenland ice sheet.  CREDIT: Jason Box / Jonathan Ryan

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