温暖化で泥炭地の炭素吸収能力が向上（Peatlands’ potential to capture carbon upgraded as temperatures rise）

2025-03-20 フランス国立科学研究センター(CNRS)

＜関連情報＞

• https://www.cnrs.fr/en/press/peatlands-potential-capture-carbon-upgraded-temperatures-rise
• https://www.nature.com/articles/s41558-025-02271-8

微生物による光合成は温暖化下で北部の泥炭地からの炭素損失を緩和する Microbial photosynthesis mitigates carbon loss from northern peatlands under warming

Samuel Hamard,Sophie Planchenault,Romain Walcker,Anna Sytiuk,Marie Le Geay,Martin Küttim,Ellen Dorrepaal,Mariusz Lamentowicz,Owen L. Petchey,Bjorn J. M. Robroek,Eeva-Stiina Tuittila,Maialen Barret,Régis Céréghino,Frédéric Delarue,Jessica Ferriol,Tristan Lafont Rapnouil,Joséphine Leflaive,Gaël Le Roux & Vincent E. J. Jassey
Nature Climate change  Published:20 March 2025
DOI:https://doi.org/10.1038/s41558-025-02271-8

Abstract

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.