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Aged permafrost carbon surged in Arctic rivers in 2018
June 2018 Mackenzie basin rivers exported previously modern-looking DOC that was suddenly centuries old, with a nitrate spike, then modern again in 2019.
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What carbon stock statistic frames the study?
Permafrost regions hold 44% of global soil organic carbon in the top 3 m.
Source: An Abrupt Aging of Dissolved Organic Carbon in Large Arctic Rivers · DOI · quote verified
How modern was Mackenzie-basin DOC through 2017?
Average F14C about 1.00, like recent vegetation and soils.
Source: An Abrupt Aging of Dissolved Organic Carbon in Large Arctic Rivers · DOI · quote verified
What F14C range appeared at Tsiigehtchic in June 2018?
1.02 to 0.73.
Source: An Abrupt Aging of Dissolved Organic Carbon in Large Arctic Rivers · DOI · quote verified
What was the 2018 network-mean DOC age?
F14C 0.85 ± 0.16, about 1,306 14C years (n = 28).
Source: An Abrupt Aging of Dissolved Organic Carbon in Large Arctic Rivers · DOI · quote verified
Where was 2018 DOC even older?
Arctic Red and Peel Rivers, F14C as low as 0.51.
Source: An Abrupt Aging of Dissolved Organic Carbon in Large Arctic Rivers · DOI · quote verified
What happened to nitrate in 2018?
A two- to threefold increase in all subcatchments.
Source: An Abrupt Aging of Dissolved Organic Carbon in Large Arctic Rivers · DOI · quote verified
Did June 2019 stay aged?
No—mean F14C returned to 0.99 ± 0.01.
Source: An Abrupt Aging of Dissolved Organic Carbon in Large Arctic Rivers · DOI · quote verified
Could the 2018 hydrograph alone explain aging?
No clear discharge–F14C relation in other years; 2018 fluxes were similar.
Source: An Abrupt Aging of Dissolved Organic Carbon in Large Arctic Rivers · DOI · quote verified
What thaw pathway do authors favor?
Supra-permafrost taliks and deeper groundwater tapping frozen organic soils.
Source: An Abrupt Aging of Dissolved Organic Carbon in Large Arctic Rivers · DOI · quote verified
How much has northern Canada warmed in 50 years?
2.3°C annually (4.3°C in winter), about 2–3 times the global average.
Source: An Abrupt Aging of Dissolved Organic Carbon in Large Arctic Rivers · DOI · quote verified
What sampling limitation do they stress?
Snapshot coverage cannot quantify event duration or carbon-cycle feedback size.
Source: An Abrupt Aging of Dissolved Organic Carbon in Large Arctic Rivers · DOI · quote verified