Hidden Carbon Fixers: How Peatland Microbes Help Balance the Climate

Cape Grassbird

26-10-2025

“Wild is not chaos. Wild is rhythm unmeasured.”

In Kingfisherish Wandering [1]

© Henry Be

Peatlands cover only 3% of Earth’s land area but store roughly one-third of global soil carbon, making them one of the planet’s most vital natural carbon sinks [2,3]. Their ability to retain carbon depends on a delicate balance between carbon uptake through photosynthesis and carbon loss through decomposition. While previous research has focused on carbon-emitting microorganisms, a new study by Le Geay et al. [4] uncovers the remarkable diversity and abundance of CO₂-fixing microorganisms (CFMs) that help stabilize this balance.

By combining DNA metabarcoding with digital droplet PCR, the researchers analyzed peat samples from four European peatlands stretching from southern France to northern Sweden. They found that CFMs account for up to 40% of total bacterial abundance, with a richness of nearly 8,000 distinct genetic types. These organisms include oxygenic phototrophs that use sunlight, chemoautotrophs that oxidize chemicals, and aerobic anoxygenic phototrophs that thrive without producing oxygen. Collectively, they form a complex microbial network capable of capturing atmospheric CO₂ through multiple metabolic pathways, particularly the Calvin–Benson–Bassham (CBB) cycle [5,6].

One of the study’s key insights is the identification of a core microbiome—a stable set of microbial species that persists across different peatland types and depths. This core community, dominated by cyanobacteria, green algae (Prasinoderma coloniale), and sulfur-oxidizing bacteria (Nitrobacter winogradskyi, Sulfurifustis variabilis), appears to drive much of the carbon fixation capacity in these ecosystems. Environmental conditions such as temperature, water table depth, and nutrient levels indirectly shape microbial diversity and structure, which in turn regulate carbon uptake.

These findings transform our understanding of peatlands from passive carbon vaults to active microbial carbon engines, revealing that many unseen species continually work to draw carbon back into the Earth. They remind us that planetary stability depends on unseen forms of life embedded in ecosystems. Recognizing and protecting these microbial networks deepens our collective ecological wisdom and reinforces the moral value of living in reciprocity with nature [7,8].

References

[1] Nguyen MH. (2025). Kingfisherish Wandering. https://www.amazon.com/dp/B0FVLLLXNW/

[2] Nichols JE, Peteet DM. (2019). Rapid expansion of northern peatlands and doubled estimate of carbon storage. Nature Geoscience, 12, 917-921. https://doi.org/10.1038/s41561-019-0454-z

[3] Strack M, et al. (2022). The potential of peatlands as nature-based climate solutions. Current Climate Change Reports, 8, 71-82. https://doi.org/10.1007/s40641-022-00183-9

[4] Geay ML, et al. (2025). Uncovering diversity and abundance patterns of CO2-fixing microorganisms in peatlands. npj Biodiversity, 4, 30. https://doi.org/10.1038/s44185-025-00099-1

[5] Berg IA. (2011). Ecological aspects of the distribution of different autotrophic CO2 fixation pathways. Applied and Environmental Microbiology, 77, 1925-1936. https://doi.org/10.1128/AEM.02473-10

[6] Figueroa IA, et al. (2018). Metagenomics-guided analysis of microbial chemolithoautotrophic phosphite oxidation yields evidence of a seventh natural CO2 fixation pathway. PNAS, 115, E92-E101. https://doi.org/10.1073/pnas.1715549114

[7] Vuong QH, Nguyen MH. (2025). On Nature Quotient. Pacific Conservation Biology, 31, PC25028. https://doi.org/10.1071/PC25028

[8] Vuong QH, La VP, Nguyen MH. (2025). Informational entropy-based value formation: A new paradigm for a deeper understanding of value. Evaluation Review. (Forthcoming) https://philpapers.org/rec/VUOIEV