Thawing Yedoma permafrost is a neglected nitrous oxide source.

Area of Science:

• Arctic Research
• Geosciences
• Environmental Science

Background:

• Permafrost thaw releases carbon, but nitrogen (N) fate and greenhouse gas (GHG) emissions remain unclear.
• Yedoma deposits, rich in carbon and N, are vulnerable to thaw and may contribute to N2O release.
• Nitrous oxide (N2O) is a potent GHG with poorly understood Arctic sources.

Purpose of the Study:

• Investigate post-thaw nitrous oxide (N2O) emissions from Yedoma permafrost.
• Link N2O release to microbial community shifts in N cycling.
• Assess the role of thawing Yedoma in Arctic climate feedbacks.

Main Methods:

• Field measurements of N2O emissions from thawing Yedoma.
• Analysis of microbial communities using targeted metagenomics of N cycling genes.
• Monitoring of Yedoma deposit stabilization, drying, and revegetation.

Main Results:

• Freshly thawed Yedoma showed low N2O emissions.
• Emissions increased significantly (1-2 orders of magnitude) within years after stabilization, drying, and revegetation.
• Metagenomics revealed shifts in N cycling microbial communities correlating with increased N2O release.

Conclusions:

• Thawing Yedoma permafrost can be a significant source of atmospheric N2O.
• Increased N availability from Yedoma drives high N2O emissions, creating a positive climate feedback.
• Understanding microbial N cycling in thawing permafrost is crucial for predicting climate change impacts.