Algae are melting away the Greenland ice sheet

From Nature:

Jason Edwards/NGC

Algae that live on snow and ice produce a kaleidoscope of colours.

Researchers are fanning out across the Greenland ice sheet this month to explore a crucial, but overlooked, influence on its future: red, green and brown-coloured algal blooms. These darken the snow and ice, causing it to absorb more sunlight and melt faster.

The £3-million (US$4-million) Black and Bloom project aims to measure how algae are changing how much sunlight Greenland’s ice sheet bounces back into space. “We want to get a handle on just how much of the darkness is due to microbes and how much to other physical factors”, such as soot or mineral dust, says Martyn Tranter, a biogeochemist at the University of Bristol, UK, and the project’s principal investigator.

Team scientists arrived near Kangerlussuaq, Greenland, this week for 6 weeks of observations. The work will continue for two more summers, exploring different parts of the ice sheet. Ultimately, the scientists hope to develop the first deep understanding of  how biological processes affect Greenland’s reflectivity.

From these results, climate modellers should be able to improve their estimates of how the ice sheet  —  which contains enough water to raise sea levels by seven metres — is likely to melt in the coming decades. The past several years, as well as the current one, have seen temperature and melting records set across Greenland.

Black and Bloom will provide “a one-of-a-kind dataset” to help researchers better understand Greenland’s future, says Marco Tedesco, a geophysicist at the Lamont-Doherty Earth Observatory in Palisades, New York.

Tranter adds that the work could also affect predictions of water supplies in other areas, such as the Himalayas, where algal blooms dot water-producing glaciers.

For decades, most studies on Greenland microbiology focused on cryoconite holes, small pits on the surface of the ice sheet that …

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