Tiny microbes in Amazon peatlands help balance the global climate

Complex organisms, thousands of times smaller than a grain of sand, have the power to shape entire ecosystems and influence the Earth’s climate.

A recent study by researchers from Arizona State University (ASU) and the National University of the Peruvian Amazon reveals the existence of an unknown family of microbes thriving in the waterlogged, low-oxygen peatlands of Peru’s northwestern Amazon rainforest.

These tiny organisms play a crucial role in the carbon cycle, with the ability to either stabilize carbon for long-term storage or release it into the atmosphere as greenhouse gases, particularly carbon dioxide and methane.

The findings highlight the vital function of tropical peatlands as one of the world’s most significant carbon storage systems. The microbes within these ecosystems determine whether the peatlands remain vast carbon reservoirs or become sources of emissions that accelerate climate change.

With human activity and climate shifts threatening their stability, the need to protect these delicate ecosystems has never been greater.

Peatland microbes and carbon regulation

Peatlands act as massive carbon vaults, storing immense amounts of organic material that has accumulated over thousands of years. This process occurs because the waterlogged conditions slow down decomposition, allowing peat to build up over time.

In the Amazonian peatlands, newly discovered microbes belonging to the ancient Bathyarchaeia group regulate this process by breaking down carbon compounds. Their metabolic flexibility allows them to survive in extreme environments, including oxygen-poor conditions.

These microbes perform a dual function. Under stable conditions, they help store carbon, keeping it locked away in the peat and reducing the risks associated with climate change.

However, environmental shifts, such as drought and rising temperatures, can activate these microbes in ways that lead to increased greenhouse gas emissions. If peatlands dry out or are disturbed, these organisms accelerate the release of stored carbon into the atmosphere, contributing to global warming.

Fragile balance of the Amazon peatlands

The microbes identified in the study are found in the Pastaza-Marañón Foreland Basin, one of the most extensive peatland regions in the northwestern Amazon rainforest of Peru.

Spanning approximately 100,000 square kilometers, this area contains vast stretches of flooded rainforest and swamps underlain by ancient peat. These peatlands store around 3.1 billion tons of carbon, roughly double the carbon held in all the world’s forests combined.

Despite their immense importance, these peatlands face increasing threats from climate change and human activity. Shifts in rainfall patterns and rising temperatures can dry out the peat, changing the microbial activity and turning these carbon sinks into carbon sources.

Deforestation, mining, and land-use changes further disrupt the natural equilibrium, accelerating the release of carbon dioxide and methane into the atmosphere.

Significance of microbes in Amazon peatland

“The microbial universe of the Amazon peatlands is vast in space and time, has been hidden by their remote locations, and has been severely under-studied in their local and global contributions,” said Hinsby Cadillo Quiroz, corresponding author of the study and researcher at ASU’s Biodesign Swette Center for Environmental Biotechnology.

“Our work is finding incredible organisms adapted to this environment, and several of them provide unique and important services – from carbon stabilization or recycling to carbon monoxide detoxification and others.”

The climate connection

For centuries, tropical peatlands have functioned as reliable carbon sinks, absorbing more carbon than they release. However, they are now at risk of becoming net carbon emitters due to rising global temperatures and changes in precipitation.

When peatlands dry out, microbial activity shifts, leading to an increase in methane and carbon dioxide emissions. This process could drastically alter global carbon cycles and intensify climate change.

According to the study, continued human-caused disruptions could result in the release of 500 million tons of carbon by the end of the century – an amount equivalent to 5% of the world’s annual fossil fuel emissions. Such an outcome would significantly amplify global warming and accelerate environmental changes worldwide.

The researchers emphasize the urgent need for sustainable land management strategies to prevent these carbon-rich ecosystems from turning into major emission sources. Preventing deforestation, reducing drainage projects, and limiting mining activities in peatlands are crucial steps in preserving their role in climate regulation.

Microbial contributions to climate

The discovery of these highly adaptable microbes provides new insights into how life persists in extreme environments and how microorganisms influence global climate systems.

These microbes consume carbon monoxide, a gas toxic to most life forms, and use it for energy, effectively reducing carbon toxicity in their surroundings.

By breaking down organic carbon, the microbes generate hydrogen and carbon dioxide – which is then used by other microbes to produce methane. This interconnected microbial network plays a pivotal role in regulating the ecosystem’s overall carbon balance.

How microbes survive in Amazon peatland

One of the most remarkable aspects of these microbes is their ability to survive in fluctuating oxygen levels. The Amazon rainforest undergoes seasonal shifts in water levels, creating an environment where oxygen availability changes throughout the year.

These microbes have adapted to thrive under both oxygen-rich and oxygen-poor conditions, ensuring their survival in the dynamic Amazonian ecosystem.

However, as climate change alters rainfall patterns and human activities increase disturbances, the balance maintained by these microbes is at risk.

Tracking shifts in temperature, precipitation, and ecosystem dynamics will be essential for predicting the future impact of microbial activity on climate stability.

Path forward for conservation

As scientists uncover the microbial universe of Amazonian peatlands, they highlight the urgent need for conservation efforts. Protecting these ecosystems requires a combination of research, sustainable land management, and local engagement to ensure their long-term stability.

The study demonstrates that the smallest organisms can have an outsized impact on global systems. When it comes to conservation, we must consider not only visible landscapes but also the microscopic life forms that sustain them.

This research, supported by the National Science Foundation, represents a significant step forward in understanding the crucial role of tropical peatlands in the global carbon cycle. As climate change continues to reshape our planet, the hidden ecosystems of the Amazon may hold key lessons for mitigating future environmental challenges.

Cadillo-Quiroz and his team plan to apply their findings to tropical peatland restoration. By deepening our understanding of microbial processes, they hope to develop strategies that enhance carbon sequestration and protect these vulnerable ecosystems from further degradation.

“Working to understand microbes and ecosystems in the lush and magnificent Amazon rainforest is the honor of my life, which I aim to use in the protection of this region in the fight against climate change,” said Cadillo-Quiroz.

The study is published in the journal Microbiology Spectrum.

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