Skip to main content

Life in the deep freeze – the revolution that changed our view of glaciers forever

I’ve been fascinated by glaciers since I was 14, when geography textbooks taught me about strange rivers of ice that crept down yawning valleys like giant serpents stalking their next meal. That kernel of wonder has carried me through a career of more than 25 years. I’ve travelled to the world’s peaks and its poles to see over 20 glaciers. Yet, when I first started out as a researcher in the early 1990s, we were convinced glaciers were lifeless deserts.

Then in 1999, Professor Martin Sharp and colleagues discovered bacteria living beneath the Haut Glacier d’Arolla in Switzerland. It seemed that glaciers, like the soil or our stomachs, had their own community of microbes, their own microbiome. Since then, we’ve found microorganisms just about everywhere within glaciers, transforming what we thought were sterile wastelands into vibrant ecosystems.

So what’s all that glacier life doing? These life forms may be invisible to the naked eye, but they can control how fast glaciers melt – and may even influence the global climate.

The glacier microbiome

Just like people, glacier microbes modify their homes. When I first saw the melting fringes of Greenland’s vast ice sheet, it looked as if a dust storm had scattered a vast blanket of dirt on the ice. Our team later discovered the dirt included extensive mats of glacier algae. These microscopic plant-like organisms contain pigments to help them harvest the Sun’s rays and protect them from harsh UV radiation. By coating the melting ice surface, they darken it, ensuring the ice absorbs more sunlight which causes more of it to melt. In western Greenland, more than 10% of the summer ice melt is caused by algae.

Bright blue glacier ice on rocky terrain.
The margin of Engabreen glacier, Norway. Grzegorz Lis, Author provided

Again, just like us, microbes extract things from their environment to survive. The murky depths of glaciers are among the most challenging habitats for life on Earth. Microbes called chemolithotrophs – from the Greek meaning “eaters of rock” – survive here without light and get their energy from breaking down rock, releasing vital nutrients like iron, phosphorous and silicon to the meltwater.

Rivers and icebergs carry these nutrients to the ocean where they sustain the plant-like phytoplankton – the base of marine food webs which ultimately feed entire ecosystems, from microscopic animals, to fish and even whales. Models and satellite observations show a lot of the photosynthesis in the iron-starved Southern Ocean could be sustained by rusty icebergs and meltwaters, which contain iron unlocked by glacier microbes. Recent evidence suggests something similar occurs off west and east Greenland too.

A microscope image depicting chains of brown rectangular cells.
Glacier algae from the Greenland ice sheet. Chris Williamson, Author provided

But glacier bugs also produce waste, the most worrying of which is the greenhouse gas methane. When ice sheets grow, they bury old soils and sediments, all sources of carbon and the building blocks for earthly life. We think there could be thousands of billions of tonnes of carbon buried beneath ice sheets – potentially more than Arctic permafrost. But who can use it in the oxygen-starved belly of an ice sheet? One type of microbe that flourishes here is the methanogen (meaning “methane maker”), which also thrives in landfill sites and rice paddies.

A waterfall at the edge of a glacier.
Leverett Glacier’s wild river, Greenland. Jemma Wadham, Author provided

Some methane produced by methanogens escapes in meltwaters flowing from the ice sheet edges. The clever thing about microbial communities, though, is that one microbe’s waste is another’s food. We humans could learn a lot from them about recycling. Some methane beneath glaciers is consumed by bacteria called methanotrophs (methane eaters) which generate energy by converting it to carbon dioxide. They have been detected in Greenlandic glaciers, but most notably in Lake Whillans beneath the West Antarctic Ice Sheet. Here, bacteria have years to chomp on the gas, and almost all of the methane produced in the lake is eaten – a good thing for the climate, since carbon dioxide is 80 times less potent as a greenhouse gas when measured over two decades.

We’re not sure this happens everywhere though. Fast-flowing rivers emerging from the Greenland Ice Sheet are super-saturated with microbial methane because there just isn’t enough time for the methanotrophs to get to work. Will melting glaciers release stored methane faster than these bacteria can convert it?

Within the thick interior of ice sheets, scientists worry that there may be vast reserves of methane. The cold and high pressure here mean that it may be trapped in its solid form, methane hydrate (or clathrate), which is stable unless the ice retreats and thins. It happened before and it could happen again.

Waking the sleeping giant

Despite the climate crisis, when I spend time around glaciers I’m not surprised by their continuing vitality. As I amble up to the gently sloping snout of a glacier – traversing its rubbly lunar-like fore-fields – I often feel like I’m approaching the hulk of an enormous creature. Sleeping or seemingly dormant, the evidence of its last meal is clear from the mass of tawny-coloured rocks, pebbles and boulders strewn around its edges – a tantalising record of where it once rested when the climate was cooler.

As I get closer, I catch the sound of the glacier’s roaring chocolate meltwaters as they explode through an ice cave, punctuated by a cascade of bangs and booms as moving ice collapses into hollow melt channels below. The winds off the ice play ominously in my ears, like the whisper of the beast, a warning: “You’re on my land now.”

The author inside a giant icy chasm within a glacier.
Exploring a frozen melt channel of the Finsterwalderbeeen glacier in Svalbard. Jon Ove Hagen, Author provided

This sense of aliveness with glaciers changes everything. Resident microbes connect these hulking frozen masses with the Earth’s carbon cycle, ecosystems and climate. How will these connections change if we take away the frigid homes of our tiny glacier dwellers? These creatures may be microscopic, but the effects of their industry span entire continents and oceans.

After a period of uncertainty in my own life, which involved the removal of a satsuma-sized growth in my brain, I felt compelled to tell the story of glaciers to a wider audience. My book, Ice Rivers, is the result. I hope the memoir raises awareness of the dramatic changes that threaten glaciers – unless we act now.The Conversation


This blog is written by Cabot Institute for the Environment Director Jemma Wadham, Professor of Glaciology, University of Bristol.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Professor Jemma Wadham

Popular posts from this blog

Powering the economy through the engine of Smart Local Energy Systems

How can the Government best retain key skills and re-skill and up-skill the UK workforce to support the recovery and sustainable growth? This summer the UK’s Department for Business, Energy and Industrial Strategy (BEIS) requested submission of inputs on Post-Pandemic Economic Growth. The below thoughts were submitted to the BEIS inquiry as part of input under the EnergyREV project . However, there are points raised here that, in the editing and summing up process of the submission, were cut out, hence, this blog on how the UK could power economic recovery through Smart Local Energy Systems (SLES). 1. Introduction: Factors, principles, and implications In order to transition to a sustainable and flourishing economy from our (post-)COVID reality, we must acknowledge and address the factors that shape the current economic conditions. I suggest to state the impact of such factors through a set of driving principles for the UK’s post-COVID strategy. These factors are briefly explained belo

Farming in the Páramos of Boyacá: industrialisation and delimitation in Aquitania

Labourers harvest ‘cebolla larga’ onion in Aquitania. Image credit: Lauren Blake. In October and November 2019 Caboteer  Dr Lauren Blake  spent time in Boyacá, Colombia, on a six-week fieldtrip to find out about key socio-environmental conflicts and the impacts on the inhabitants of the páramos, as part of the historical and cultural component of her research project, POR EL Páramo . Background information about the research can be found in the earlier blog on the project website . Descending down the hill in the bus from El Crucero, the pungent smell of cebolla larga onion begins to invade my nose. The surrounding land transforms into plots of uniform rows of onion tops at various stages of growth, some mostly brown soil with shoots poking out along the ridges, others long, bushy and green. Sandwiched between the cloud settled atop the mountainous páramos and the vast, dark blue-green Lake Tota, all I can see and all I can smell is onion production. Sprinklers are scattered around, dr

IncrEdible! How to save money and reduce waste

The new academic year is a chance to get to grips with managing your student loan and kitchen cupboards. Over lockdown the UK wasted a third less food than we usually would. This is brilliant, as normally over 4.5 million tonnes of edible food is wasted from UK homes every year. For students, it’s even higher. The average cost of food waste per student per week is approximately £5.25 - that's about £273 per year !  It’s not just our bank accounts that are affected by food waste – it’s our planet too. The process of growing, making, distributing, storing and cooking our food uses masses of energy, fuel and water. It generates 30% of the world’s CO₂ greenhouse gas emissions. The same amount of CO₂ as 4.6 million return flights from London to Perth, Australia! So it makes sense to keep as much food out of the bin as possible, start wasting less and saving more.  Start the new term with some food waste busting, budget cutting, environment loving habits! Here’s five easy ways to reduce