How the Microscopic World Adapts to Melting Glaciers

By John Heilprin

June 16, 2023

Two recent studies published by scientists at the Swiss Federal Institute of Technology Lausanne (EPFL) River Ecosystems Laboratory (RIVER), part of EPFL’s School of Architecture, Civil and Environmental Engineering (ENAC), found that climate warming alters glacier-fed stream ecosystems worldwide.

They’re part of the “Vanishing Glaciers – What Else Besides Water Is Lost?” project, which is studying the microbial life underlying hundreds of thousands of glacier-fed streams that are vanishing.

In recent years scientists have been looking more closely at the one of the impacts of climate change: the release of life-forms such as bacteria and other microbes that have been in cold storage for countless years and are making their way back into the environment. 

Led by Tom Battin, a professor of environmental sciences at EPFL, an international team of researchers in Switzerland, Luxembourg, the United States and Saudi Arabia, with support from the Swiss-based Nomis Foundation, has made microbial and biogeochemical analyses among some of the world’s highest peaks.

Challenges to one of the world’s key transition ecosystems

One of the studies focused on the diversity and adaptive strategies of the microbiome in glacier-fed streams, while the other looked at the accelerating decomposition of organic matter in glacier-fed streams and the changing microbiome structure as glaciers shrink.

Their findings showed that glacier-fed streams may become more important to the natural carbon cycle.

In a Nature review article commissioned earlier this year, Battin and other researchers examined carbon fluxes in river networks, which they called “the largest biogeochemical nexus between the continents, ocean and atmosphere” but are less understood than the global carbon cycle of oceans and land systems.

The limited understanding makes it hard to predict how climate change may alter the timing and spatial distribution of riverine carbon sequestration and greenhouse gas emissions.

Time for a new global river iniative?

Glacial biodiversity is gaining importance among climate researchers who are finding that biological processes on the ice surface are also contributing to its warming.

The ice also preserves ancient genetic material, sometimes from creatures that long ago disappeared. When it melts, the ice could release that material, with fascinating implications, but it also could put potentially harmful bacteria and viruses back into the environment. About 1,000 micro-organisms, some previously unknown, have recently been identified in permafrost in the Swiss Alps.

After quantifying the organic and inorganic carbon flux from land to global rivers, Battin and other researchers showed another important aspect. The net ecosystem production and carbon emissions shift the organic to inorganic carbon balance from land to the coastal ocean.

“We argue that a global river observing system will play a key role in understanding river networks and their future evolution in the context of the global carbon budget,” they wrote.

Fertile ground for bioprospecting

Their work shows the importance of the “transition ecosystems” highlighted in the GESDA 2022 Science Breakthrough Radar.

The Radar notes that these transition environments boast a rich biodiversity, including cold-adapted microbes, algae, fungi and archaea, making them fertile ground for bioprospecting.

“They also provide vast amounts of nutrients, such as phosphate, which enters the planet’s mountain river systems in the form of “glacial flour”: fine-grained rock ground from bedrock,” the Radar says.

“Life on earth depends on phosphorus, and as glaciers disappear, less and less phosphate enters glacier-fed waterways, with potentially huge impact on life downstream.”

A new international repository

Within the next five years, the Radar anticipates that scientists around the world will collect samples of the cold-adapted biodiversity that exists in these frontier ecosystems and undertake the beginnings of an international repository to store and preserve such microorganisms.

Fashioned after the Svalbard Global Seed Vault, the repository would hold genetic sequences of these microorganisms that arer shared to an open-access database. 

A new wave of Earth modeling

Within the next 10 years, the Radar anticipates that the transition ecosystems will inform Earth modeling through the integration of biodiversity models of these transition ecosystems into larger-scale Earth-system simulations.

That, in turn, is expected to produce more accurate predictions of the effects of glacier loss.

Metagenomic analysis

Within the next 25 years, the Radar anticipates that the glacial bioprospecting will pay off with metagenomic analysis of the world’s glacial transition ecosystems.

The result is expected to be a comprehensive public repository of genetic information about these rapidly disappearing environments.

The findings in the Breakthrough Radar

Based on the 2022 Science Breakthrough Radar®, here’s where we stand in several important areas:

Downstream from this microscopic world our relationship to the ocean must change: We also urgently need to understand the ocean better and help repair its ecosystems where possible. As we deploy autonomous sensors to gather relevant data and keep exploring the vast biodiversity of the ocean, we hope to discover more about these myriad cold-adapted organisms that are rapidly disappearing from retreating glaciers and flowing downstream. Radar, page 110.

Interface between the cryosphere and the hydrosphere: Though the places where glaciers melt into the streams they feed are one of the world’s key transition ecosystems, they are steadily disappearing before our eyes. The rate at which the world’s glaciers thinned has doubled in the first two decades of this century and, due to climate inertia, a lot of changes expected over the next quarter century are locked in. There is a closing window to redouble our bioprospecting efforts before many transition ecosystems melt away and knowledge about their micro-organisms is lost. “What happens downstream of the cryosphere is a bellwether for climate change because these zones are extremely sensitive to warming.” Radar, page 139.

Managing climate externalities: Since the industrial resolution, atmospheric levels of carbon dioxide have been rising steadily and the world is already more than halfway to the upper limit for the United Nations-brokered Paris Agreement, which calls for no more than 2° Celsius of warming or 1.5° if possible. The World Meteorological Organization says there’s a 66% likelihood the annual average near-surface global temperature between 2023 and 2027 will reach the 1.5° limit for at least a year. Climate change raises the prospect of mass migration away from inhospitable regions and urgent international attention is needed to better prepare for these mass movements. Radar, page 208.

What people say: Eco-regeneration and geoengineering, including decarbonization and ocean stewardship, elicit strong engagement from citizens, according to analysis of more than 6 million social media posts. Radar, page 264.