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.


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.”


From EurekAlert!

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William Haas
October 12, 2019 2:40 am

The ERC itself should travel up there and cover the discolored ice with an inch thick layer of styrofoam to insulate the ice and keep it white. They will not be allowed to make use of fossil fuel in any way in creating the required styrofoam, installing it, or transporting themself to and from Greenland. I wonder how many tons of styrofoam will be required to do the job?

Reply to  William Haas
October 12, 2019 6:03 am

Styrofoam, like Kleenex, is a registered trademark. EPS, expanded polystyrene, is generic. Otherwise, it is cultural appropriation. Typical foam is mostly gas. The common blowing agent today is mostly CO2. Density is 2 to 4 #/cubic foot. It does have the advantage of being 100% recyclable and nontoxic. It is also decomposed by UV as long as it gets good exposure.

It would be more economical to air spray tons of bio-toxins as long as we intend to micro manage nature.

Bryan A
Reply to  Mark
October 12, 2019 8:30 am

Send Christo up there with a googolplex of white sheets and have him stake them out above the darkened ice areas.

Reply to  Mark
October 12, 2019 8:50 am

Xerox used to be a word used for any photocopying and for the machines no matter who made them. Frisbee is still the standard nomenclature for any plastic disk thrown for fun. One can lose their Trademark by ” Genericism”.

Reply to  rah
October 14, 2019 6:08 am
Reply to  Mark
October 12, 2019 11:12 am

One of the first lessons in my Naval Machinist Mates school tool identification class (yes there really is such a class)- Instructor holds up a crescent wrench “This is not a crescent wrench, it is an open end adjustable wrench, Crescent is a brand name. If you put down Crescent wrench on the identification test I will mark you down for that answer.” Of course outside of that class, everyone still calls it a crescent wrench.

Hot under the collar
Reply to  William Haas
October 12, 2019 10:22 am

€11 million? Likely more pre-ordained, pal review research, given the ‘climate change’ meme to guarantee funding by the taxpayer. Not sure if I’m getting the wrong impression, but it looks like this article is suggesting that this dark algae is under the ice and only darkens the ice where it is already melting at the edge of the ice shelf? Algae, growing at the edge of the ice shelf, where the sunlight has already reached it, is likely a normal, natural phenomena and unlikely to lead to further melting inland from the shelf edge.

Samuel C Cogar
Reply to  William Haas
October 12, 2019 12:36 pm

If the glacial is growing it must be snowing.

Doesn’t the winter snowfall cover up that glacial ice?

If its not snowing the glacial can’t be growing ….. and its probably melting, from the bottom edge of course.

How long is a Greenland summer and how warm does it get.

Must be it gets hot enough to melt the snow overburden before the heat attacks the glacial ice, ….. right?

October 12, 2019 2:48 am

No matter what I’m sure it’s our fault.

Reply to  rah
October 12, 2019 4:58 am

Just why these glacier algae grow so densely is not really known at the moment

I am flabbergasted that the damned potty Potsdammers have not instantly linked this to CO2. Maybe they are holding off since proving it is CO2 is the basis of their next grant application.

Bryan A
Reply to  Greg
October 12, 2019 8:24 am

Just wait…it’s coming…
CO2 leads to warmer temperature…
Warmer temperature leads to greater algae growth…
CO2 enriches algae growth…
Greater algae growth leads to darkening spread…
Darkening spread leads to greater melt…
Greater melting leads to lessened albedo…
Lesser albedo leads to further increasing temperatures…

Joe Crawford
Reply to  Bryan A
October 12, 2019 12:00 pm

It will be interesting to watch. These glacier algae could be the first actually proven positive feedback mechanism that ‘climate science’ has been able to come up with. You can bet they’ll really go bonkers if it proves out.

Bryan A
Reply to  Joe Crawford
October 12, 2019 2:40 pm

Yep, just insert a plethora of $10 – $20 words (as my dad used to call multi-syllable words) and their paper is written.

Reply to  rah
October 12, 2019 5:48 am

not us….maybe they will figure out what’s feeding the algae….where it’s really coming from

naw…..they will say it’s our fault again

Rod Evans
October 12, 2019 3:00 am

“When it all was over
We had to find another place
But Swiss time was running out
It seemed that we would lose the race
Smoke on the water, fire in the sky
Smoke on the water
We ended up at the Grand hotel”
Deep Purple……..
Just guessing ,this will be on the research team’s play list.

Reply to  Rod Evans
October 12, 2019 6:38 am

And Frank Zappa and the Mother’s had the best place around!

Reply to  Rod Evans
October 12, 2019 11:33 am

Take away their flare guns!

October 12, 2019 3:01 am

Ah there it is finally: the long sought for adverse effect of plant growth stimulating CO2.

Repent repent, Greenland ice is sliding rapidly into the ocean and we are all going to drown (sarc!!)

Reply to  Hans Erren
October 12, 2019 3:44 am

The algae remove CO2 from the atmosphere. They should harvest the algae to make useful stuff. link

October 12, 2019 3:06 am

Why always the AGW bias? Is this just to get the funding?

Why not study the reduction in ice-sheet albedo caused by Chinese industrial soot. Do an image search for BIack Ice Sheets, and see how contaminated some of this ice is.

In fact, much of the global warming over the last 3 decades may have been caused by the industrialisation of China; their terrible record on emissions and pollution; the reduction in Arctic ice albedo; and the huge amount of extra insolation absorption that that provides.

No need to invoke CO2 at all….

BIack Ice in Greenland.


Roger Knights
Reply to  ralfellis
October 12, 2019 4:05 am

“Why not study the reduction in ice-sheet albedo caused by Chinese industrial soot. ”

Maybe these purple algae are feeding on the soot (?).

Reply to  Roger Knights
October 12, 2019 5:00 am

Possible. Is that why the algae are increasing?

Logic would suggest that the surface of an ice sheet is a temperature constant, no matter what the ambient air temperature. While it is a known fact that the solar TSI has remained constant. So a logical variable that could account for increased algal growth might be nutrients from industrial emissions – not temperature.

That theory would be easy to test. Core down through the Holocene Maximum (HM) ice layers, and look at what happened 8,000 years ago. It was 2 degrees warmer in the Arctic during the HM, so if temperature was the cause of algal growth you should find copious algal byproducts and remains there. If there was no algal increase during the HM, then again it is likely that industrial emissions are a more likely cause than temperature.


Reply to  ralfellis
October 12, 2019 6:53 am

Good remarks. Algae likes minerals, just like ocean plankton likes minerals brought up by upwelling bottom water.

Reply to  ralfellis
October 12, 2019 7:50 am

I would think that on the top of glaciers, minerals of all types would be the primary growth limiting factor.

John in NZ
Reply to  ralfellis
October 12, 2019 10:59 am

While the algae grows, does it remove CO2 from the bubbles of air trapped in the ice, thus lowering the CO2 levels in those bubbles that Climate Scientists look for thousands of years later?

Did anyone look for dead algae in the Vostok ice core samples?

Reply to  ralfellis
October 12, 2019 11:18 am

There won’t be any old algae in the ice. Glacial ice moves. The algae only grow in the ablation zone of the ice-cap, this ice will either melt or calve in a relatively short time. The old ice can only be found up at the ice divide where no algae can grow.

Reply to  Roger Knights
October 12, 2019 5:07 am

It’s an insurance policy, if the pause does turn to cooling, they already have their aerosols explanation on hand.

Just goes to show, if you hang around long enough, you get to see history repeat itself.

Reply to  Pumpsump
October 12, 2019 5:16 am

Pumpy – I think you have the albedo feedback arse about face.

The lower albedo on the ice sheets is a warming feedback – the same feedback mechanism that warmed each interglacial by 12 degrees c, in just 5 kyr.


Reply to  ralfellis
October 12, 2019 5:07 am

“Why not study the reduction in ice-sheet albedo caused by Chinese industrial soot.”

Because China is already communist.

steven mosher
Reply to  ralfellis
October 13, 2019 2:27 am

haha. now thats funny

October 12, 2019 3:17 am

About 20 meters algae along the edge if the glacier. Contribution to the drowning of mankind.

Mike McMillan
Reply to  nobodysknowledge
October 12, 2019 8:56 am

At 20 m per year, that should reach the middle of the ice sheet in around 20,000+ years. Let’s just hope the algae don’t get started on the eastern side, too.

October 12, 2019 3:35 am

FYI, some technical characterizations of these algae blooms:

Benning, L. et al.,
“Biological impact on Greenland’s albedo”,'s%20albedo.pdf [2014]
Marek Stibal et al.,
“Algae Drive Enhanced Darkening of Bare Ice on the Greenland Ice Sheet”, [2017]

Reply to  Johanus
October 12, 2019 3:39 am

Thanks for the links.

October 12, 2019 3:37 am

I recall reading in high school that, triggered by the loss of Titanic and later spurred by shipping losses due to ice during WWI, some tests were done in the 1920s, 30s, and/or 40s with carbon black being intentionally spread atop icebergs to stimulate faster melting – and that the tests were a total bust. The bergs were even impervious to air-dropped bombs. Not surprising given that only ~10% of the bergs’ mass was exposed and the amount of heat transfer that would be required to be effective. The experience of those tests might be instructive for this new project.

Rod Evans
October 12, 2019 4:11 am

The study will look at how darkening the ice via growth of algae i.e. natural biological variation is significantly impacting melt rates of the ice.
This is a bit like asking the question, “Is water wet”
The real issue is, whether algal growth is any different now to what it has been in history. A secondary question then arises, “if it is different then what drives the difference”?
My money is on a study result showing, algae growth is dependant on the environmental conditions in its local area.
Another €11 million spent.

October 12, 2019 4:18 am

11 Million!!!!! Thats a lot pf flights and lunches

michael hart
October 12, 2019 4:31 am

So how much of the Greenland ice sheet gets covered in fresh white snow many times every year?
About 100.00%, I would guess. Was this photo taken towards the end of the melt season? Probably.
Is their claimed effect likely to make any measurable difference? Almost certainly not.

Reply to  michael hart
October 12, 2019 11:25 am

“Was this photo taken towards the end of the melt season?”

No, quite early. The snow-free ice zone is always much wider late in the melt season:

michael hart
Reply to  tty
October 12, 2019 5:46 pm

Thanks. What was the date?

Reply to  michael hart
October 13, 2019 5:46 am

How should I know? It depends on where in Greenland the photo is taken.

Bruce Cobb
October 12, 2019 4:34 am

Uh ohs. It’s the beginning of the end. The warming causes purple algae to grow which causes ice to melt which decreases albedo, adding additional warmth in a faster and faster spiral, especially once the permafrost starts to melt, releasing methane – the famed “Arctic Death Spiral”. We’re doomed.

October 12, 2019 4:39 am

11 mil pounds for that??
utter rubbish
if the algaes there its natural cycle
if they dont like it then spray some fertiliser or copper suplhate on it
either would knock it off pdq I reckon
and cost little
leave it be…but theres no money or fame in that

Patrick MJD
October 12, 2019 5:13 am

Blue carbon, green/red algae now purple algae?

Are these people making sure all causes of climate doom is inclusive?

Reply to  Patrick MJD
October 12, 2019 7:35 am

Right — more “disasters of color” need to be hired, for diversity.

P.S. Despite the current marxist-meme, from grade-school education, white is actually all colors, darkness is lack of colors.

Reply to  Patrick MJD
October 12, 2019 7:52 am

Don’t forget yellow snow.

October 12, 2019 5:33 am

Decades ago some climate clowns proposed to cover the Arctic with a black cover to stop the anthropogenic induced coming ice age.

Now that some algae are doing so on the Greenland ice sheet (by the way, with no effect at all), the same clowns invoke anthropogenic induced GW and accelerated ice sheet melting …

One for sure big effect of natural climate change :
– the multiplication of climate clowns.

M__ S__
October 12, 2019 5:37 am

When it’s dark the blackbody radiation should increase from the algae patches, making it colder.

Reply to  M__ S__
October 12, 2019 7:54 am

From the article, the algae is beneath the surface of the ice, so it should have little affect on the ice’s black body radiation characteristics.

Reply to  MarkW
October 12, 2019 11:22 am

They are on the surface of the ice. You should know by now never to rely on EurekAlert for factual information.

Clarky of Oz
October 12, 2019 6:06 am

Oh dear. Is this a whole new ecology starting up? Who knows where it will lead. Will we see new plankton, fishes, mammals, flowering plants, grasses, trees? Is Greenland turning green? Heaven forbid. Oh dear, what is the world coming to?

October 12, 2019 6:19 am

Global warming is a meaningless consideration for a life form that exists at a constant 0 degrees C, or colder. Ice bound algae cannot exist at any higher temperature, regardless of the air temperature.

Also, the sunlight energy that is absorbed by algae does NOT transmit to the ice – but rather,it is converted to biomass via photosynthesis. An algae layer is NOT the equivalent of an inorganic soot or dust coating on the surface of ice.

Reply to  Duane
October 12, 2019 7:16 am

What would you know? You haven’t got 11 million Euros and he who has the most grants wins. You need to find some gold or silver algae of your own as the Royal purple is taken.

October 12, 2019 6:46 am

Who wouldn’t look forward to spending 11M euros of other peoples’ money.
Leane G Belling is following in the footsteps of Elon Musk.

October 12, 2019 7:34 am

I can’t seem to find the right article to fit my question in so I decided to go with this one. As you know the climate zealots have been working overtime to discredit the warming that occurred during the MWP. They have admitted it was likely as warm as today during the MWP in Greenland and in Northern Europe. But they only make this admission because of the significant historical and anthropological record of the Vikings in Greenland and similar evidence in Northern Europe.

But the climate zealots argue that the global temperature was lower than today during the MWP since similar historical evidence of warming doesn’t exist in much of the rest of the world. Lately I have been seeing studies conducted in South America and Africa that use temperature proxies to try and show no higher temperatures on those continents during the MWP.

I am not a scientist but it seems to me that when looking for temperature proxies its easy to cherry pick what proxies you use in order to obtain the result you desire. Can any of the scientists here confirm my suspicions on this forum shopping for temperature proxies or am I way off base on my suspicions ? Thanks for the help in advance.

Reply to  Marc
October 13, 2019 6:44 am

Keep coming back and reading. You’ll see you are spot on.

Walter Sobchak
October 12, 2019 8:36 am

“if future sea level rise is to be predicted accurately, ”

Facepalm. Their predictions are garbage anyway. One more made up parameter isn’t going to make a #$%&@ bit of difference.

October 12, 2019 9:40 am

There must be some nutrient there that the algae are eating. Also, since these blooms seem to appear close to the ice/ocean interface, it would seem that whatever it is comes from the ocean. There could be lots of reasons for this but I will offer one speculative plausible scenario:

Bacteria are now evolving that eat plastic. One very efficient strain was discovered in a landfill in Japan back in 2006. It appears that it evolved production of an enzyme specifically designed to break down PET plastic. Plastic is potentially a very high energy source. Organisms feeding on plastic might produce waste that is, in turn, a nutrient for other life forms or maybe this species of algae has independently evolved a process to break down plastic dust and eat it. If one organism has evolved the capacity to digest plastic, one would assume that others have too, or will shortly. The number of organisms that will evolve to eat plastic will likely increase as plastic is such a high potential energy source it would not likely go unused.

Also, the western side of Greenland is where all the people live. It could be that something produced by the human population is providing a nutrient for these algae.

Bruce Cobb
Reply to  crosspatch
October 12, 2019 10:00 am

Is it bigger than a breadbox?

Reply to  crosspatch
October 12, 2019 10:13 am

Other ideas are that:

The proximity of the ocean keeps the temperature optimal for the growth of this species.

Some mutation occurred in this species that makes it particularly well-adapted to the conditions there and it is displacing less well-adapted colonies and is spreading.

It is an invasive species that only recently arrived there.

Some OTHER species has undergone a mutation that provides it with more nutrients.

Maybe just an abundance of whale and seal crap now that populations of both are increasing.

Clyde Spencer
Reply to  crosspatch
October 12, 2019 10:14 am

What will happen to our ubiquitous products made of plastic if these evolving bacteria become widespread and abundant? We will need ‘telephone sanitizers’ to keep everything from being eaten.

Reply to  crosspatch
October 12, 2019 10:35 am

There is abolutely nothing new about this. The algae only grow where the temperature rises above zero in summer, i e on the lower parts of the ice cap, particularly on the west side. The nutrients come from the dust fallout on the ice. Though it is quite possible that the amount of air-borne nutrients is increasing. Not from soot though. Soot fallout on the ice peaked c. 1915 and has decreased since as the amount of coal ash from the US has decreased:

comment image

And the increase in CO2 is very likely to stimulate growth.

Reply to  tty
October 12, 2019 1:59 pm

The CO2 fertilization would be ubiquitous across Greenland. It wouldn’t start in one area and spread. So I would rule out any atmospheric cause. Temperature related causes wouldn’t likely start in the north and move south, it would likely be reversed.

Reply to  tty
October 13, 2019 5:33 am

The melt area is largely on the west side and the algae only grow in melting snow. Like everything living the need liquid water.

Ed Zuiderwijk
October 12, 2019 9:51 am

Nothing a good dose of bleach won’t solve.

October 12, 2019 10:10 am

Sigh. If these “climate scientists” could ever come up with something new. Snow algae are well known and have been extensively studied for about 200 years. The algae of the Greenland icecap were carefully studied by the two first scientific expeditions to study the icecap in 1870 and 1883:

John MacDonald
Reply to  tty
October 12, 2019 1:16 pm

I regularly marvelled at the pink algae on the snow slopes of the Alberta Rockies while spring skiing in the early 1980s. Nothing new.

October 12, 2019 11:36 am

If the algal growth is really increasing you would expect the summer albedo to be decreasing. However the albedo change is not very dramatic, a decrease from 81.8 % in 2000 to 81.0 % in 2017:

comment image

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.

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:

Coeur de Lion
October 12, 2019 12:38 pm

god I cd do w four million quid.

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.

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
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.…/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.]

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. 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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