Article Dans Une Revue Nature Climate Change Année : 2025

Microbial photosynthesis mitigates carbon loss from northern peatlands under warming

La photosynthèse microbienne atténue les perte de carbone des tourbières avec le réchauffement climatique

Martin Küttim
Ellen Dorrepaal
  • Fonction : Auteur
Mariusz Lamentowicz
Owen Petchey
Bjorn Robroek
Eeva-Stiina Tuittila

Résumé

The future of the northern peatland carbon (C) sink is uncertain as the effects of warming on microbial metabolisms are unclear. While increased microbial CO2 emissions are expected under warming, the response of microbial photosynthesis remains unknown, complicating predictions of net microbial effects on peatland carbon emissions. Here, using a continental-scale experimental study, we show that warming amplifies microbial photosynthesis by 3.4 mgC m−2 h−1 per 1 °C increase. By 2100, this increase translates to a gain of 51.1 Tg of carbon per year from the northern peatland area under the pessimistic SSP 5-8.5 climatic change scenario, offsetting ~14% of projected heterotrophic CO2 emissions in northern peatlands. By linking field and microcosm experiments, we further show that enhanced microbial photosynthesis accelerates peatland CO2 uptake as photosynthetic microbial-C subsidies stimulate nutrient mineralization. These results underscore the importance of photosynthetic microbes for mitigating carbon emissions and supporting long-term carbon storage in peatlands.

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hal-05095946 , version 1 (25-11-2025)

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Samuel Hamard, Sophie Planchenault, Romain Walcker, Anna Sytiuk, Marie Le Geay, et al.. Microbial photosynthesis mitigates carbon loss from northern peatlands under warming. Nature Climate Change, 2025, 15 (4), pp.436-443. ⟨10.1038/s41558-025-02271-8⟩. ⟨hal-05095946⟩
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