Yedoma

Yedoma is ice-rich, carbon-bearing permafrost deposited during the Pleistocene in parts of Siberia and Alaska. Its thaw can expose large stores of ancient organic carbon.

Permafrost: Ground that remains at or below 0°C for at least two consecutive years. Yedoma is a distinctive, ice-rich type of permafrost terrain.
Permafrost thaw: The warming and degradation of ground that has remained frozen for at least two years. Thaw destabilizes yedoma and exposes previously frozen sediment and organic matter.
Radiocarbon dating: A method for estimating the age of carbon-containing materials by measuring radioactive carbon-14. Dating yedoma organic matter helps establish when its carbon was deposited.
Kolyma Lowland: A low-lying region of northeastern Siberia containing extensive permafrost terrain. It contains extensive yedoma deposits and is a major setting for field research.
Permafrost distribution mapping: The mapping of where permafrost occurs and how its properties vary across landscapes. Yedoma's uneven distribution makes its total area and volume difficult to estimate.
Ground ice: Ice occurring within soil, sediment, or rock, including ice formed in place and buried ice. Large volumes of ground ice give yedoma deposits their characteristic ice-rich structure.
Thermokarst lake: A lake formed in a depression created by thawing and subsidence of ice-rich permafrost. Yedoma thaw can create lakes that accelerate further ground warming and carbon release.
Permafrost carbon inventory: An estimate of the amount and distribution of organic carbon stored in permafrost soils and sediments. Yedoma's high carbon content makes its extent important to regional inventories.
Lena River Delta: A large Arctic river delta in northeastern Siberia, underlain in part by permafrost. Yedoma deposits and thaw-related landscapes occur across parts of the delta.
Permafrost carbon uncertainty: Uncertainty in estimates of carbon stored in permafrost and its future release. Sparse observations and variable deposits complicate estimates of yedoma carbon stocks.

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