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Methane-Eating Bacteria & Archaea Saving Earth from the Ravages of Climate Change (and cattle burps)

Issue 119 - April 2025, Terrestrial Topics

How are methane-eating microbes responding to climate change? Are they physiologically adjusting to temperature changes and other stressors to influence the amount of methane entering the atmosphere? This is the tale of three species of bacteria and a class of archaea that gain energy from methane instead of sunlight and respond differently to thrive in a changing climate.

Methane is a greenhouse gas that traps heat, warming the planet and contributing to climate change. It is metabolized by Archaebacteria and methanogenic archaea, which feed on decaying organic matter in oxygen-poor environments such as wetlands, permafrost, and cattle ranches, releasing methane in the process. The amount of methane released by these bacteria is rising as climate change alters conditions.

In the muck and mire, alongside the methane-producing bacteria and archaea, are methanotrophs, which consume methane. Nature thrives on cycles. These bacteria are located in aerobic (oxygen-rich) muck above anaerobic sediment. Methanotrophs represent one of Earth’s most vital methane sinks, metabolizing up to 90% of the methane produced in wetlands and atmospheric methane in soils into proteins and sugars.

How are methane-eating bacteria responding to climate change? Are they physiologically adjusting to temperature changes and other stressors to influence the amount of methane entering the atmosphere?

Researchers recently went to a bog, removed the top layer, and brought methane-eating bacteria back to the laboratory. Culturing methanotrophs is a hazardous undertaking because these bacteria require an enormous amount of oxygen and hydrogen. The amount of oxygen is often less than optimal for bacteria because scientists are concerned about their safety due to the risk of explosions. 

Three methane-eating bacteria from the genus Methylobacter were collected from the bog. These were common methanotrophs found in wetlands worldwide. Under varying conditions, researchers observed the amount of methane consumed, the growth rate of the bacteria, and the internal changes within the cells. The quantity of methane the bacteria consumed depended on their condition. The bacteria consumed more methane when the temperatures were either warmer or cooler than they were accustomed to, because they had to expend a lot of energy to repair issues in their cells.

At 60 degrees Fahrenheit, one species of bacteria consumed a significant amount of methane to compensate for the less-than-ideal temperature. Methane consumption decreased by 30 percent when the temperature was increased to 70 degrees, yet the growth rate remained consistent. Researchers observed that as the temperature decreased, the bacteria consumed more methane and produced additional ribosomes to metabolize more proteins. The increase in protein production allowed the bacteria to maintain their processing speed even when the temperature dropped. Methane consumption increased with diminishing temperatures.

Some bacteria increased methane uptake when the environment became too warm. As the molecules increased their motion, more methane was used to repair damage or increase the rigidity of the cell wall. 

How methane-eating bacteria will affect global methane emissions in the future remains as murky as the bog muck from which these methanotrophs came. The study found that depending on the type of methane-eating bacteria that dominates the ecosystem will indicate the reaction when the temperature rises. The good news is that methanotrophs are diverse in every ecosystem. The one most fit for the situation (or needing the most repairs) will increase methane consumption. Fortunately, there is another domain of microbes eating methane.

Archaea, a domain of primitive prokaryotes distinct from bacteria, derives its name from the Greek word meaning old and primitive. These single-celled organisms produce methane through anaerobic cellular respiration. Conversely, Methanoperedens are archaea that decompose methane in soils, groundwater, and the atmosphere to form complex carbohydrates.

Researchers recently sampled Methanoperedens from underground soil, aquifers, and riverbeds. They were surprised to find packets of DNA within single-celled organisms, known as extrachromosomal elements, that transfer genes often via viruses between bacteria and archaea. These packets allow microbes to have on-hand beneficial genes from neighboring organisms.

The extra-chromosomal elements are a relatively large conglomeration of diverse genomes assimilated from many organisms held within one organism and named “Borgs” after the assimilation of many planet parts in Star Trek.

The archaea cell already consumes methane. It possesses an arsenal of genetic elements to draw from, allowing the cell to have a higher capacity should conditions change. Said the lead author, “It basically creates a condition for methane consumption on steroids, if you will.”

Evidence indicates that whenever methane emissions rise, bacteria and archaea are poised to increase their methane consumption. They take the energy of methane to combine carbon dioxide and water into carbohydrates, sequestering carbon at the base of the ecosystem’s food pyramid. We can tip the balance from too much industrialization towards more natural environments, such as wetlands, grasslands, fields, forests, and natural river-beds.

By replacing hard surfaces and heat islands with vegetation and soils, we can better tackle the challenges of climate change, create more habitats for industrious microbes, and initiate the process of cooling the planet. We must allow more rainwater to infiltrate the ground to sustain life during periods of drought. Let’s restore the natural cycles of water, carbon and methane, and allow nature to heal the planet with the aid of methane-eating bacteria and borg-packing archaea.

Morning mist on the Allagash River
Morning mist on the Allagash River
Rob Moir in Greenland

Dr. Rob Moir is a nationally recognized and award-winning environmentalist. He is the president and executive director of the Ocean River Institute, a nonprofit based in Cambridge, MA, that provides expertise, services, resources, and information not readily available on a localized level to support the efforts of environmental organizations. Please visit www.oceanriver.org for more information.

References

Please note that the forth reference is a preprint and has not yet undergone peer review.

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