Probing the Dark Side of Life on Arctic Glaciers


As Dr Jason Box of Ohio State University, USA, recently reported, even wildfire soot deposition may contribute particles to the ice surface too.


The study’s lead author, glaciologist Dr Tristram Irvine-Fynn explained: “For several years now, I have been particularly intrigued how this cryoconite is formed and how it is then transported across a glacier surface by the flow of melt water. When I used time-lapse photography I found the dust’s movement was very complex, and I wondered if the microbes get washed away from the surface or not.”


So the team set out to measure the ‘microbial budget’ of an Arctic glacier by counting the number of microbes entering, leaving and being stored on the glacier’s surface using a sophisticated new method able to count single bacteria.


L-R: Dr Arwyn Edwards and Dr Tristram Irvine-Fynn examine a large, exposed cryoconite deposit on a high-arctic glacier in Svalbard. (Image: Dr Nozomu Takeuchi).


Aberystwyth University researchers have measured the ‘microbial budget’ of a glacier surface for the first time, discovering how bacteria may help melt glaciers.


Glaciers and permanent snow contain around 24 million cubic kilometres of freshwater, just over two thirds of the Earth’s total. The effects of climate and accelerating melting of glaciers and ice sheets worldwide have raised considerable environmental concern.


And it now appears that it’s not only rising air temperatures that are causing their decline. Tiny specks of living matter that appear on the ice surface are also increasing the melting.


Writing in Environmental Microbiology, scientists at the Aberystwyth University’s Institutes of Geography & Earth Sciences (IGES) and Biological, Environmental & Rural Sciences (IBERS), along with colleagues based at the Universities of Sheffield and Bristol, have just added a twist to the tale.


They have published the first seasonal budget of tiny microbial life forms at the surface of a glacier in the Norwegian High-Arctic archipelago of Svalbard.


Far from being smooth skating rinks, glacier surfaces are irregular and almost always covered with a fine dusting of what looks like potting compost. This ‘compost’ is a material called ‘cryoconite’ – which translates as ‘cold dust’. It is made from a combination of small rock particles, dust and microbes, which are blown onto the glacier from surrounding mountains or deposited in rain and snowfall.


Dr Sara Rassner, a former PhD student at IBERS and co-author of the study explained, “Previously we had to count bacteria one-by-one using a microscope, which was tedious and prone to error. By using flow cytometry – effectively shining a laser light through a stream of water, and counting electronically - we can quickly make very precise counts of every cell containing DNA.”


Samples of glacier melt water and surface ice were collected and analysed along with results from dust traps made from upside-down Frisbees. The data collected revealed some surprising results.


Every hour, about 10 million cells are washed away by melt water from a square metre of the glacier’s surface. This number of microbes transported from the glacier’s surface contains a volume of carbon.


“Amazingly, the volume of carbon that is exported from the studied glacier each summer is similar to a bag or two of sugar from your local supermarket!” added Dr Irvine-Fynn. Although this may seem a small amount, the study was on just one small glacier; the total volume of carbon is many times larger when you consider the number of glaciers worldwide.


Dr Arwyn Edwards of IBERS, who co-authored the study explained, “If we assumed the glacier we studied is representative of glaciers everywhere, they would lose at least 3.5 thousand trillion cells every summer, which is roughly the same number of cells estimated to be living on and in three billion people.”


But this is just one part of the story. What the team found concerning is that the export of cells is dwarfed by the number of microbes that are retained within the ice surface.


“We find that many cells landing on the ice are simply being trapped there,” Dr Irvine-Fynn explained. The Aberystwyth scientists found that during the cold Arctic summer, the total mass of microbial carbon that is captured across the studied glacier’s surface is equivalent to a sack of compost from a garden centre.


L to R: Dr Tristram Irvine-Fynn and Dr Arwyn Edwards on Svalbard. (Image: Dr Jenny Bussell).


This is a particular concern because the growing microbes glue together the dust, carbon and tiny rock particles and darken the ice surface, which increases the amount of the sun’s energy that melts the glacier.


“We are calling this phenomenon ‘biological darkening’ and it appears to be a significant factor which may accelerate the rate at which glaciers melt away” said Dr Irvine-Fynn.


Ironically, “even a decade ago many scientists viewed glaciers as lifeless lumps of ice” said the study’s co-author, Dr Arwyn Edwards.


“What we find fascinating,” said Dr Irvine-Fynn “is that through biological darkening, life on ice may itself be contributing to the rapid melt of many glaciers, as well as delivering primary nutrients and DNA to the terrain exposed as those glaciers shrink.”


It is hoped that future studies could now tell us if this ‘biological darkening’ is a long-term and global phenomenon.


The Climate Change Consortium of Wales (C3W) and the Natural Environment Research Council (NERC) funded the study.


Paper Reference: Irvine-Fynn, T. D. L., Edwards, A., Newton, S., Langford, H., Rassner, S. M., Telling, J., Anesio, A. M. and Hodson, A. J. (2012), Microbial cell budgets of an Arctic glacier surface quantified using flow cytometry. Environmental Microbiology, 14: 2998–3012. doi: 10.1111/j.1462- 2920.2012.02876.x


MORE INFO. 164


Spider Skin Image Captures Grand PrizFEI Image Contest


18th Microscopy of Semi-Conducting Materials (MSM XVIII)


St Catherine's College, University of Oxford, 7-11th April. Conference Co-Chairmen: John Hutchison (Oxford) and Thomas Walther (Sheffield) Co-sponsored by EMAG, Institute of Physics and endorsed by Materials Research Society


The conference will focus on the most recent advances in the study of the structural and electronic properties of semiconducting materials by the application of transmission and scanning electron microscopy. The latest developments in the use of other important microcharacterisation techniques including scanning probe microscopy and X-ray topography and diffraction will also be featured. Developments in materials science and technology covering the complete range of elemental and compound semiconductors will be described.


For full programme and details on registration contact www.rms MORE INFO. 165


Gold Award for IPLEX TX Videoscope


Texture of the skin of a spider, with a hair root and brochosomes from a leafhopper preyed upon by the spider. Image acquired using the FEI Quanta™ DualBeam.


FEI has announced Maria Carbajo from the Universidad de Extemadura, Spain, as the winner of the FEI Image Contest for her ‘Spider Skin’ image.


In 2012 FEI invited owners and users of FEI microscopes to submit their best nanoscale images for a chance to win great monthly prizes. From over 230 high-quality submissions FEI selected 16 monthly image winners to compete for the grand prize of two airline tickets to a United States destination.


For more information on the competition visit www.fei.com MORE INFO. 166


Olympus Corporation’s IPLEX TX industrial videoscope was recently awarded Gold Medal at the International Engineering Fair MSV 2012, the largest industrial fair held in Eastern and Central Europe.


Held each year in the Czech Republic's second-largest city of Brno, ithis event is a major world-class industrial fair supported by the Czech government and various Czech industry groups - 1,873 exhibiting companies from 32 countries were reported to have participated at the end of last year.


Olympus received the gold medal for the IPLEX TX videoscope, the second gold medal Olympus has been awarded in the last five years. With the growing needs for quality inspection in the automotive industry, a key industry in Eastern and Central Europe, the IPLEX TX ultra-thin videoscope has gained wide recognition for its contribution to improved inspection accuracy in small automotive parts.


MORE INFO. 167 UK SPM 2013


This meeting covers a wide range of topics associated with Scanning Probe Microscopy including main techniques such as atomic force microscopy and scanning tunnelling microscopy as well as more specialised versions.


Scanning Probe Microscopy Meeting 2013 26-27 June. Venue: Weetwood Conference Centre, Leeds, UK Scientific Organisers: Neil Thomson, University of Leeds, UK Confirmed Plenary Speakers for 2013: Professor Toshio Ando Professor Daniel Mueller Professor Klaus Kern


If you are interested in exhibiting or sponsoring this event contact chloe@rms.org


MORE INFO. 168


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