Home / Themes / Cryosphere / ‘Germ Theory’ for glaciers & ice sheets adds new dimension to melting

 
A recently published paper by Aberystwyth University scientists reveals that the fate of Earth’s biggest stores of freshwater – glaciers and ice sheets – is closely linked to the lives of the smallest life-forms –microbes- living within them.

Much attention is focused on the future of glaciers and ice sheets because of their sensitivity to warming climates.

Melting glaciers and ice sheets will affect the livelihoods, food and water security of hundreds of millions of people. However research published this month in Wiley Interdisciplinary Reviews: Water has highlighted how the study of microbial processes in glacier environments will be important to understand how glaciers and ice sheets respond to climate change.

The paper’s lead author, microbiologist Dr Arwyn Edwards, of IBERS at Aberystwyth University said; “Much attention is focused on the future of glaciers and ice sheets because of their sensitivity to warming climates. Melting glaciers and ice sheets will affect the livelihoods, food and water security of hundreds of millions of people. Greenland may feel like a world away from us in the UK, but its ice sheet holds the equivalent of 7.5 metres of sea-level rise and as this melts it risks catastrophic effects on coastal erosion and sea defences here.”

Dr Edwards explains, “Very crudely, we can think of glaciers as having a “bank account”, with credit being supplied as fresh snowfall, and debit being paid as ice melts. We have compiled an evidence base that microbes are important creditors and debitors to this glacial bank account.”

The paper describes how the “credit” is accumulated as microbial proteins in clouds help catalyse the formation of snowflakes, and microbes live in snowpacks, and “debit” is taken as microbial ecosystems darken the ice surface, increasing the amount of the sun’s energy absorbed by the ice. Dr Edwards said: “we have taken to describing this as a “germ theory” for glaciers because of the implications for how glaciers work”.

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photo & video courtesy of Sara Penrhyn Jones

Dr  Edwards recently gained recognition for his work in The Microbiome Awards for his study of microbes in glaciers. The award follows a decade of research and a 3 month research marathon during the summer of 2014 in Greenland, Svalbard, the Swedish Arctic and the Alps with still more work to do in South Georgia.

The paper builds on current research at Aberystwyth University on glacier ecosystems; the paper’s co-author, glaciologist Dr. Tristram Irvine-Fynn said “Using sophisticated techniques in flow cytometry, we calculated the number of microbes living in the surface of glaciers worldwide. We were shocked to find numbers comparable to well-known habitats such as rainforest soils or the surface of the oceans” These microbes may be tiny, but they are important: “We need to understand this accumulation of microbes in more detail to see how this effect multiplies the impact of climate change on melting glaciers” Dr Irvine-Fynn added.

The association between microbes and ice runs deep as it includes microbes buried underneath glaciers.

The paper’s co-author and co-principal investigator of the US National Science Foundation’s successful project to drill into Antarctica’s Subglacial Lake Whillans, microbial geochemist Dr. Andrew Mitchell said:

“Glacial ice covers 11% of Earth. We didn’t know until a decade ago that life could survive underneath the ice, but now as a result of our work we know how microbes “eat” rocks to survive under the ice, and produce methane, a powerful greenhouse gas”.

The team are set to further investigate the links between ice and life as they are setting out to map the biology of glacial ice across the Arctic and Alps this summer, with fieldwork in Svalbard, Greenland, the Canadian and Swedish Arctic and Austrian Alps as part of projects led by Dr. Edwards and Dr. Irvine-Fynn funded by the Royal Society, Natural Environment Research Council, European Union and the Climate Change Consortium of Wales.

“Hopefully our fieldwork will help provide a snapshot of how microbial life in glaciers responds to and magnifies the change in glaciers and ice-sheets at a key point as our climate warms” said Dr. Edwards.

Edwards, A., Irvine-Fynn, T., Mitchell, A. C. and Rassner, S. M. E. (2014), A germ theory for glacial systems?. WIREs Water. doi: 10.1002/wat2.1029 http://onlinelibrary.wiley.com/doi/10.1002/wat2.1029/abstract (open access)