Deep Purple — future biological darkening of the Greenland Ice Sheet

Purple algae are making the western Greenland Ice Sheet melt faster, as the algae darken the ice surface and make it absorb more sunlight

GFZ GeoForschungsZentrum Potsdam, Helmholtz Centre

This photo shows the change in surface darkness as the cold dry white snow (left side of of image) starts melting to grey (centre of the image), to reveal the dark ice underneath (right side of image). The dots on the left are people to give a sense of the scale. Credit Laura Halbach
This photo shows the change in surface darkness as the cold dry white snow (left side of of image) starts melting to grey (centre of the image), to reveal the dark ice underneath (right side of image). The dots on the left are people to give a sense of the scale. Credit Laura Halbach

The ERC (European Research Council) has awarded an €11 million Euro Synergy grant called DEEP PURPLE to Liane G. Benning at the German Research Centre for Geosciences (GFZ) Potsdam, Germany, Alexandre Anesio at Aarhus University, Denmark and Martyn Tranter at University of Bristol, UK. Their common goal is to examine over the next six years (2020-2026) the role of glacier algae in progressively darkening the Greenland Ice Sheet surface in a warming climate.

The three researchers have already changed our understanding of why the ice darkens during the melt season by identifying the purple-pigmented ice algal blooms in the ice surface. These glacier algae are pigmented deep purple to shield their vital elements from the intense UV radiation in sunlight. During the melt season there are so many of these deep purple algae that they look as black as the soot from tundra fires. They form a dark band that has been progressively growing down the western side of the Greenland Ice Sheet during the summer melt season for the last 20 years, causing increased melting of the darkening ice.

Just why these glacier algae grow so densely is not really known at the moment, and neither is whether they will grow in the new melt zones on the ice sheet surface, to the north and to the ice sheet interior, as the climate continues to warm.

Project DEEP PURPLE

Questions such as this need answering if future sea level rise is to be predicted accurately, since Greenland melt is a major driver of current sea level rise.

Project DEEP PURPLE aims to answer these questions over the next six years, combining curisoity driven science about how the glacier algae grow and interact with their icy habitat, and societally relevant research into the processes that lead to ice surface darkening that are needed by ice melt modellers.

The scientists will work around many different sites in Greenland, making measurements of surface darkening, glacier algae density, how much soot and dust the algae trap on the surface and the physical properties of the melting ice surface to finally understand, how biological darkening occurs, and to predict where and when it will occur in the future.

Amazing opportunity

This type of research needs the expertise of microbiologists, glaciologists and particulate biogeochemists, working in synergy, because only with a knowledge of all three aspects of melting ice surfaces can biological darkening be understood. DEEP PURPLE will host a team of 9 post doctoral researchers, 6 PhD students along with the three PIs.

Liane G. Benning states: “I am looking forward to the opportunity to examine the complex interactions between the different light-absorbing particulates – microbes, minerals and soot – down to the smallest detail. As the ice melting season becomes longer and longer and the darkening of the ice surface by algae covers greater proportions of the ice sheet, it is all the more important to understand the processes and mechanisms behind it. In order to quantify how significantly the melting Greenland ice contributes to global sea-level rise.”

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From EurekAlert!

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Curious George
October 12, 2019 12:11 pm

“As the ice melting season becomes longer and longer ..”
“This type of research needs the expertise of microbiologists, glaciologists and particulate biogeochemists, working in synergy.”
They should add meteorologists to the mix. Meteorologists would tell them that the length of an ice melting season depends on elevation. Elevation is plentiful in Greenland .. for that, they should also add physical geographers.

tty
Reply to  Curious George
October 13, 2019 5:38 am

“As the ice melting season becomes longer and longer ..”

Which DMI who keeps weather stations there somehow has failed to notice:

http://polarportal.dk/fileadmin/polarportal/meltarea/MELTA_combine_SM_DK_20191012.png

Coeur de Lion
October 12, 2019 12:38 pm

god I cd do w four million quid.

Dennis
October 12, 2019 6:59 pm

“I am looking forward to the opportunity to examine the complex interactions between the different light-absorbing particulates – microbes, minerals and soot – down to the smallest detail……………..”
and spending 11 million euros on Me and My family and friends.

Mark.R
October 12, 2019 8:09 pm

“algae darken the ice surface and make it absorb more sunlight”

So the ice get more sunlight into it with the darken algae on top?.

Should it say more heat?.

October 13, 2019 2:25 pm
Editor
October 14, 2019 6:14 am

I posted about this on the Science News FB page, my additions might interest people here:

Ric Werme On a bicycle tour in 1974, I was (at first) annoyed to see pastel yellow and magenta coloration on snowfields around Rainy Pass in the North Cascades, but I soon realized they were the bacterial colonies I had read about in SN a few months before.

It looks like there’s a dark purple alga that is geoengineering the ice edge in parts of Greenland.

https://www.eurekalert.org/pub…/2019-10/ggph-dp-101119.php

One “feature” of the Internet is that the percentage of new developments in science that I first read about in SN has dropped quite a bit.

Ric Werme Found it – it was four years before and the color is from algae, but I remembered that people hoped this simple ecosystem would be relatively easy to understand.

[This might be limited to subscribers.] https://www.sciencenews.org/archive/life-snowbank

Ric Werme It turns out science has known about “crimson” snow in Greenland since 1818, I don’t know if that is related to the deep purple alga.

https://www2.palomar.edu/users/warmstrong/plaug98.htm says in small part:

The colour of the fields of snow was not uniform; but, on the contrary, there were patches or streaks more or less red, and of various depths of tint. The liquor, or dissolved snow, is of so dark a red as to resemble red port wine. It is stated, that the liquor deposits a sediment; and that the question is not answered, whether that sediment is of an animal or vegetable nature. It is suggested that the colour is derived from the soil on which the snow falls: in this case, no red snow can have been seen on the ice.”

Johann Wundersamer
October 21, 2019 6:56 pm

Just why these glacier algae grow so densely is not really known at the moment, and neither is whether they will grow in the new melt zones on the ice sheet surface, to the north and to the ice sheet interior, as the climate continues to warm.
________________________________________________

It’s the competitions, stupid.

These algae are the only living competitors from flora & fauna who learned thanks to adaptation to survive as dark wild growth on the ice and get all the co2 available.

The winner takes it all.

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