Ice sheet microbes and melt

Greenland contains the largest continuous mass of ice in the northern hemisphere; an area over 2 million km2. The frequency of Greenland surface melting has increased, likely as a result of human-induced climate warming, with the melt-area covering almost the entire ice sheet surface in 2012 (Ngheim et al. 2012; Box et al, 2013; Tedesco et al. 2013).

Ablation zone extent on the Greenland ice sheet: July 8 (left) and July 12 (right). On July 8, ~40% of the ice sheet was melting. Four days later, ~97% of the ice sheet surface had thawed.  Credit: Nicolo E. DiGirolamo, SSAI/NASA GSFC, and Jesse Allen, NASA Earth Observatory

Ablation zone extent on the Greenland ice sheet: July 8 (left) and July 12 (right). On July 8, ~40% of the ice sheet was melting. Four days later, ~97% of the ice sheet surface had thawed. Credit: Nicolo E. DiGirolamo, SSAI/NASA GSFC, and Jesse Allen, NASA Earth Observatory

Although its fair to say that higher temperatures mean more melt, the response of earth’s glaciers and ice sheets to climate warming is complex, also depending upon a range of feedbacks (e.g. Box et al, 2012). For example, when ice melts, liquid water runs over its surface, sometimes collecting in pools and lakes. Liquid water is a more effective absorber of sunlight than snow or ice, so the overall reflectivity (also called albedo, Greek for ‘whiteness’) of the ice decreases. The result is faster ice melt. Melting promotes more melting.

Box et al’s (2012) image of albedo anomaly in summer 2012. Darker blue means greater darkening compared to average albedo.

Box et al’s (2012)
image of albedo anomaly in summer 2012. Darker blue means greater darkening compared to average albedo.

Not only melt water that reduces  Greenland ice sheet albedo. A variety of aerosol ‘impurities’ further reduce surface albedo. These include black carbon (BC) derived from incomplete combustion of fossil fuels, other industrial activity, biomass burning, and wildfire. Black carbon can be transported across the hemisphere through the atmosphere and deposited on ice, and currently the impacts remain uncertain (Hodson, 2014). Dark Snow field science is examining this question in detail based on 2013 field measurements and planned measurements for June-August, 2014.

Black Carbon - produced during the incomplete combustion of fossil fuels

Black Carbon – produced during the incomplete combustion of fossil fuels (photo, wikimedia commons)

The presence of microbes on the ice surface also alter albedo and can therefore influence melt rates (Yallop et al, 2012). They do so by growing and adding dark biomass to the ice, causing mineral fragments to aggregate and resist removal (flushing) by melt water, and by producing dark humic substances and pigments. There may even be a relationship between microbial activity and BC. Yet, it is not yet known whether microbes metabolise BC and reduce its impact, or cause it to “stick” to the ice surface and prevent its removal by flushing (Hodson, 2014).

Many microbes on the Greenland ice sheet inhabit ‘cryoconite’ holes; cylindrical tubes ‘drilled’ into the bright ice surface ice by dark cryoconite debris. The debris is a loose bonding of minerals encased in microbial biomass (e.g. Gribbon, 1979; Cook et al, 2010). Cryoconite holes on the Greenland ice sheet likely provide favourable conditions for photosynthesis by: 1.) maintaining light intensities that are high but not harmful because ultraviolet radiation is not transmitted by water; 2.) providing nutrients in melt water flowing in through the hole walls; and 3.) providing relatively long term (years) storage of microbes. This also promotes proliferation of bacteria and “grazers” that feed upon other microbes. These factors make cryoconite holes active and biodiverse ice sheet habitats (Hodson et al, 2008).

Cryoconite holes – generally considered to be the most biodiverse microbial habitats on glacier surfaces

Cryoconite holes – generally considered to be the most biodiverse microbial habitats on glacier surfaces (photo, J. Cook)

Despite being the most studied biological entity on the surface of the Greenland ice sheet, cryoconite holes remain poorly understood in terms of their biological community dynamics, thermodynamics, evolution and impact on albedo. Further, the characteristics of the holes themselves, and the microbes inhabiting them, have been shown to vary depending upon location on the ice sheet (Stibal et al, 2012), and these spatial patterns probably also evolve over time. Edwards et al (2014) recently found microbial communities to be extremely dynamic in response to environmental change, while Irvine-Fynn and Edwards (2014) showed that hydrological and glaciological processes might also influence microbial activity. Cryoconite holes will provide research foci for some members of the field team in summer 2014. For further information on cryoconite, see: herehere; and here.

by Joseph Cook and Jason Box


Box, J.E., Fettweis, X., Stroeve, J.C., Tedesco, M., Hall, D.K., Steffen, K. 2012. Greenland ice sheet albedo feedback: thermodynamics and atmospheric drivers. The Cryosphere, 6, 821-839. open access.

Box, J.E., Cappelen, J., Chen, C., Decker, D., Fettweis, X., Mote, T., Tedesco, M., van de Wal, R.S.W., Wahr, J. 2013. Greenland ice sheet. Arctic Report Card.

Cook, J., Hodson, A., Telling, J., Anesio, A., Irvine-Fynn, T, Bellas, C. 2010. The mass-area relationship within cryoconite holes and its implications for primary production. Annals of Glaciology, 51 (56): 106-110

Edwards, A., Mur, L. A.J., Girdwood, S. E., Anesio, A. M., Stibal, M., Rassner, S. M.E., Hell, K., Pachebat, J. A., Post, B., Bussell, J. S., Cameron, S. J.S., Griffith, G. W., Hodson, A. J. and Sattler, B. (2014), Coupled cryoconite ecosystem structure–function relationships are revealed by comparing bacterial communities in alpine and Arctic glaciers. FEMS Microbiology Ecology. doi: 10.1111/1574-6941.12283

Gribbon, P.W. 1979. Cryoconite holes on Sermikaysak, West Greenland. Journal of Glaciology, 22: 177-181

Hodson, A., Anesio, A.M., Tranter, M., Fountain, A., Osborn, M., Priscu, J., Laybourn-Parry, J., Sattler, B. 2008. Glacial Ecosystems. Ecological monographs, 78 (1): 41-67

Hodson, A. 2014. Understanding the dynamics of black carbon and associated contaminants in glacial systems.WIREs Water 2014, 1:141–149. doi: 10.1002/wat2.1016

Irvine-Fynn, T.D.L., and A, Edwards. 2014. A frozen asset: The potential of flow cytometry in constraining the glacial biome. Cytometry Part A 85 (1), 3-7

Nghiem, S. V., D. K. Hall, T. L. Mote, M. Tedesco, M. R. Albert, K. Keegan, C. A. Shuman, N. E. DiGirolamo, and G. Neumann (2012), The extreme melt across the Greenland ice sheet in 2012, Geophys. Res. Lett., 39, L20502, doi:10.1029/2012GL053611.

Stibal, M., Telling, J., Cook, J., Mak, K.M., Hodson, A., Anesio, A.M. 2012. Environmental controls on microbial abundance on the Greenland ice sheet: a multivariate analysis approach. Microbial Ecology, 63: 74-84.

Tedesco, M., X. Fettweis, T. Mote, J. Wahr, P. Alexander, J.E. Box, B. and Wouters. 2013. Evidence and analysis of 2012 Greenland records from spaceborne observations, a regional climate model and reanalysis data, The Cryosphere, 7, 615-630, doi:10.5194/tc-7-615-2013.

Yallop, M.L., Anesio, A.J., Perkins, R.G., Cook, J., Telling, J., Fagan, D., MacFarlane, J., Stibal, M., Barker, G., Bellas, C., Hodson, A., Tranter, M., Wadham, J., Roberts, N.W. 2012. Photophysiology and albedo-changing potential of the ice-algal community on the surface of the Greenland ice sheet. ISME Journal, 6: 2302 – 2313


Camp Dark Snow 2014

At last, Camp Dark Snow 2014 has a date (17 June) and a location; 42 nautical miles east of Kangerlussuaq on the southwestern Greenland ice sheet, at an elevation 1250 m above sea level.
Screen Shot 2014-04-06 at 2.13.39 PM
Here each summer the ice melts down 1.48 m on average since 2008, only 0.3 m in 2009; and  2.1 m in the record melt year of 2012 (data after Fausto et al. 2012). This location is host to the @Promice_GL “KAN_M” climate station.

Dirk van As maintains the KAN_M climate station in the pre-melt of 2013
When we start the camp, there will be some residual winter snow on ice, how much, hard to predict, though we can see below that southwest Greenland has had this year 30-50% of normal precipitation. If this drought keeps up, we’ll see an earlier than normal bare ice emergence and higher than normal melt.
precipitation difference from normal according to an observationally constrained atmospheric circulation model. Brown isolines indicate less than average precipitation. The contour interval is 10, 30, 50, 70, 100, 110, 120, 150 percent.
Late June when we should put in our camp, there will be snow and slush in some areas until the snow is gone. Ideally, we have both snow and bare ice when we set the camp. The Digital Globe image below depicts what the surface would look like by say mid July once the snow cover is gone.
Screen Shot 2014-04-06 at 11.19.49 AM
spacing between the melt ponds is 800 m (2300 ft)

Our field experiments, to be elaborated further in future posts, include documenting the importance of dust, black carbon, and microbes in snow and ice melt.

The field team so far includes:

  • Drs. Marek Stibal video; Karen Cameron; and Prof. Jason Box of Geological Survey of Denmark and Greenland (GEUS)
  • Prof. Martyn Tranter; University of Bristol in England
  • Drs. Arwyn Edward; Tristram Irvine-Fynn, a video; Alun Hubbard, a video of the University of Aberystwyth in Wales
  • Dr. Joseph Cook of the University of Derby in England
  • Alia Khan, blog of the University of Boulder, CO, USA
  • media specialist Peter Sinclair, a video
  • media specialist Dr. Sara Jones, a video

It is by pooling resources among these groups that we can do more/better science and get the science message out.

Work Cited

  • Fausto R. S., D. Van As and PROMICE Project Team (2012), Ablation observations for 2008-2011 from the Programme for Monitoring of the Greenland Ice Sheet (PROMICE). In Bennike O, Garde AA and Watt WS eds. Review of survey activities 2011. GEUS, Copenhagen, 25-28 (Geological Survey of Denmark and Greenland Bulletin 26).


persistent warm over Arctic Ocean, persistent cold over US and continental Asia

I updated my calculation of running 5-day temperature anomalies versus the same 5-day period for the ‘climate normal’ (a.k.a. most recent 30 year period beginning on a “1″ year) 1981-2010. These data are from the US NCEP NCAR Reanalysis mixture of observations from satellites, ground stations, aircraft and numerical modeling.

Most striking to me is the Arctic Ocean area persisting warm…

Arctic20140206The most recent map (that does not include forecast data) has the warm anomaly along the US west coast turned to cold anomaly. So, the whole US is in the cold in the most recent 5 day average. The warmest temperatures over the Arctic Ocean are 17 C above the 1981-2010 average for this 5 day period.



Here’s the situation over the US for the region bounded by 70 to 105 longitude west and 38 to 55 latitude north…



2014 Warm Arctic – Cold Continents pattern

As I begin planning for another Greenland expedition to study ice melt, I decided to explore whether the cold eastern North America, was part of what some scientists are calling the Warm Arctic – Cold Continents pattern. Examination of US NCEP NCAR Reanalysis data reveals that YES, the story has an important Arctic climate dimension.

While it’s easy to understand that abnormal summer warmth promotes high melting, winter warming also promotes melting through the loss of snow, ice, and land “cold content”. The higher the ground temperature, the fewer degrees of heating it takes to reach the melting point. Thus, winter warming preconditions the surface for earlier melt onset and more melting overall.

That’s one reason why this January’s Arctic climate concerns me. Greenland temperatures have remained more than 5 degrees C above average after the first week of the year. The snowpack heating the abnormal warmth increase the likelihood of an earlier melt onset and above average Greenland melting this coming summer.


5 day average running temperature anomaly for the region 61 to 82 deg. north latitude and 30-65 deg. west longitude

The Arctic north of 77 degrees north latitude, essentially the Arctic Ocean has also, according to this climate data, been abnormally warm much of January 2014.Arctic

Examining the geographic pattern of temperature departure from normal, a.k.a. the temperature anomalies, we see a Warm Arctic – Cold Continents pattern.Temperature_2014_28-32_anom

The average of the first 33 days of 2014, above average temperatures prevail for Greenland, Baffin Island, Alaska, the Arctic Ocean, the north Atlantic, and the western US with while the eastern North America, northern Europe and Siberia are feeling anomalous cold.


Below is a map representing the period I was in San Francisco for the AGU meeting. I recall skidding on a thin ice layer the morning of 8 Dec walking across Yerba Beuena park. At this time, the whole US was feeling the cold.
The figure below represents the US for the region bounded by 70 to 105 longitude west and 38 to 55 latitude north. Just as impressive as the cold is the abnormal warmth 10-20 Jan. We call this “weather whiplash”.

A climate change connection?

Dr. James Overland and colleagues at NOAA have reported on the Warm Arctic – Cold Continents pattern, occurring December 2009 and 2010. Overland  writes:

“In the last five years, we’ve seen the jet stream take on more a wavy shape (left hand map below) instead of the more typical nice oval around the North Pole (right hand map below). This waviness is leading to colder weather down in the eastern U.S. and eastern Asia. Whether this is normal randomness or related to the significant climate changes occurring in the Arctic is not entirely clear, especially when considering individual events, but less sea ice and snow cover in the Arctic and relatively warmer Arctic air temperatures at the end of autumn suggest a more wavy pattern to the jet stream and more variability between the straight and wavy pattern.”


Thanks Peter Sinclair for some text comments.

Dark Snow Project First Science Results

12 December, 2013 – Presented at an invited American Geophysical Union (AGU) talk, a calculation enabled based on our field data indicate:

  • The likely 2012 albedo drop from black carbon, through amplifying feedback with sunlight, doubles for the ice sheet as a whole through the melt season.
  • Summer 2012 black carbon concentrations likely increased cumulative surface net heating by 20-40% for the ice sheet as a whole.
  • In low elevation areas where snow cover overlies impurity rich bare ice, the feedback multiplication can be more than a factor of 5 lower albedo than the hypothetical case with no black carbon.
  • The sensitivity of the ice sheet to light absorbing impurities is high, especially in areas with seasonal snow cover that when melted away earlier, lead to more surface melting.
  • The sensitivity to light absorbing impurities is greatest when there is little summer snowfall. The snowfall brightens the surface and shields, at least partially, the dark particles from the sunlight. Low summer snowfall prevailed in 2012 and other years with negative Arctic Oscillation Index.
albedo perturbation

by end of melt season a -1% pre-melt albedo perturbation doubles the ice sheet average albedo reduction to -2%

The AGU presentation is watchable online using “AGU13″ as the passcode and searching “black carbon” to find the talk entitled “examining the role of black carbon and microbial abundance in Greenland ice sheet albedo feedback“.

Alluded to in the talk’s title and this video below is that the science is evolving to tackle another key aspect of cryosphere climate sensitivity, the importance of microbial abundance in Greenland ice sheet albedo feedback. So, stay tuned. The Dark Snow Project is gaining momentum!

Visiting and monitoring South Greenland dark ice

I’m spending a week flying out of Narsarsuaq, south Greenland, with colleague Dr. Robert Fausto, to maintain climate stations equipped to monitor surface ice melt in great detail. Part of the Danish PROMICE network, the stations obtain surface energy and mass budget closure. The closure means that calculated melt matches with observed melt.

coming in to land at a PROMICE climate station, one of 22 on Greenland ice operated by GEUSPhoto J. Box.

Flying across this vast space and on the ground, I’m is struck by how abundant snow algae and other light absorbing impurities can be. The low reflectivity impurities amplify the effects of the increasing melt season. Increased melt means a shorter duration of highly reflective snow cover. The prolonged exposure of an impurity-rich bare ice surface multiplies melt rates. I’ve calculated that without this albedo feedback, the increase in melt rates would amount to half of what’s observed. Some of this feedback is due to ice crystal rounding. Some is due to the impurities. Measuring the relative importance of metamorphic and impurity driven albedo reduction is a subject of our work.

boots on the ice offer a close look (and to sample) impurities concentrating at the surface. The fact is, much of this dark material is from cyanobacteria and blue-green algae. Photo J. Box.

puddles often form with this kind of algal slick’. Photo J. Box.

It’s exciting to be working with Dr. Marek Stibal who studies the microbial environment on Arctic ice. Together with his data, the surface energy exchange data from the PROMICE climate stations and Danish Meteorological Institute’s regional climate modeling (Follow @Greenlandsmb), we have a powerful approach to unravel more detail from the melt story in Greenland.

South Greenland Dark Ice. Photo J. Box.

Snow accumulates in crevasses forming snow bridges that one would rather fly over. In between, impurity-rich ice absorbs up to 80% of the Sun’s energy. Photo J. Box.

Surface melt water mingles with impurity rich Greenland ice. Photo J. Box.

Robert Fausto maintains a climate station equipped to measure downward and upward solar energy, among many other climate parameters as part of the Danish PROMICE network (Follow @PromiceGL). Photo J. Box. (Follow @Climate_Ice)

Improvised Masterpiece

We’re just now reintegrated into society after a 17 day Greenland expedition that started and remained best characterized by a supporter’s comment.

“I never worked on a meticulously planned ambitious project that didn’t turn into improvised as you go masterpiece.”

As put in our new Rolling Stone article;

“The first day we arrived in Greenland, our helicopter pilot was nowhere to be found.” Sadly, our friend Tore Sivertsen was without an Air Operators Certificate. Red tape had him grounded. For how long, we didn’t know. But we did know that we couldn’t wait.

So, with less than 2 minutes on the ground, I was in contact with Air Greenland charter. A helicopter was available in another town. Within an hour, we were buying commercial air to Ilulissat for the next day. There was just enough time to visit the bridge that washed out the previous year in a record setting flood and begin video recording.

Dark Snow Expedition begins

Thanks to your support, we’re headed to Greenland Monday 24 June through 10 July to measure the impact of wildfire soot as a multiplier in snow and ice solar heating. Soot is a multiplier in the “albedo feedback” that has doubled surface melting on Greenland in the last decade. Jet stream heat waves alone don’t double Greenland’s sea level contribution. Also since me last message to you, we’ve now published a unified theory that links surface melting with ice flow.

Before more science, a word on funding. Our crowdfunding campaign, due to its novelty and nearly 30 news pieces on our work, has DOUBLED a very generous initial $50k seed grant. That’s right, we’ve made it to $100k, just enough to make the expedition happen!

Our samples will facilitate an additional and electric new science, measure solar heating feedbacks from microbial activity. That’s right, in addition to putting fire season soot into context with atmospheric heating in its role of amplifying solar heating of snow and ice, we’ll have a chance to put into context, for the first time, the role of algae in darkening the cryosphere. I’m thinking that pollution amy be fertilizing algae. That with the expanding melt season provide another important change to the surface reflectivity of the ice. Even if the soot and algae change the snowreflectivity only 1%, it’s still important because that change gets wound into a feedback loop, an amplifier. I’m whispering this algae angle because we don’t want to let out this idea to too many people. We’ll update you anyhow. This is also your expedition too.

Tomorrow, our videographer Peter Sinclair is to arrive Copenhagen. Instead of spending precious expedition funds on a hotel, Peter will stay with us and sleep on our sofa. That’s also right, I’m a Dane now, have taken a post as Professor philosophical lead of 10 PhD glaciologists at the Geological Survey of Denmark and Greenland (GEUS). It’s an honor.

Inspired by Peter, I’ve created a two new videos (1 and 2) that promote the GEUS Program for the Monitoring of the Greenland Ice Sheet (PROMICE). We launch our revised web site tomorrow. You have a 12 hour sneak preview!

Monday morning, we’ll meet in the airport waiting area with a Rolling Stone writer who’ll write a tour de force of our expedition so the story gets out further. He returns after the first 2 days of theexpedition.

After taking our first set of samples and shooting video 25-29 June, Peter and I will hole up and prepare an outreach blast, reporting using video and blogging. So, sign up for the RSS, and and follow @DarkSnowProject@PromiceGL; and like us on facebook to stay tuned.

Thanks again for making our science happen.

More soon.