Climate warming and elevated CO₂ alter peatland soil carbon sources and stability

Area of Science:

• Environmental Science
• Soil Science
• Biogeochemistry

Background:

• Peatlands store a significant portion of global soil organic carbon (SOC).
• The impact of climate change, specifically warming and elevated atmospheric CO2 (eCO2), on peatland SOC composition and stability remains poorly understood.
• Understanding these changes is crucial for predicting the future of peatland carbon reservoirs.

Purpose of the Study:

• To investigate how warming and eCO2 affect the molecular composition of SOC in a boreal peatland.
• To infer the sources (microbial, plant, fire) and stability of SOC under simulated climate change conditions.
• To assess the net effect of climate change on peatland carbon storage.

Main Methods:

• Analysis of SOC molecular composition using advanced techniques.
• Distinguishing between plant-, microbe-, and fire-derived carbon inputs.
• Quantifying changes in specific SOC compounds like suberin (root-derived) and cutin (leaf/needle-derived).

Main Results:

• Warming alone increased SOC decomposition, decreasing microbe- and plant-derived SOC.
• Warming combined with eCO2 led to an increase in plant-derived SOC compounds.
• Root-derived inputs (suberin) increased, while leaf/needle-derived inputs (cutin) decreased under warming and eCO2.
• These shifts suggest a move towards SOC pools with faster turnover rates.

Conclusions:

• Climate change, through warming and eCO2, alters SOC composition and sources in boreal peatlands.
• Warming enhances decomposition, while eCO2 influences carbon input pathways, particularly favoring root-derived compounds.
• The combined effects indicate a potential destabilization of carbon storage in peatlands, necessitating further research into their future role in the global carbon cycle.