Erosion of organic carbon in the Arctic as a geological carbon dioxide sink
Hilton, Robert G.
Grocke, Darren R.
MetadataShow full item record
Soils of the northern high latitudes store carbon over millennial timescales (103 yrs) and contain approximately double the carbon stock of the atmosphere1-3. Warming and associated permafrost thaw can expose soil organic carbon and result in mineralisation and carbon dioxide (CO2) release4-6. However, some of this soil organic carbon may be eroded and transferred to rivers7-9. If it escapes degradation during river transport and is buried in marine sediments, then it can contribute to a longer-term (>104 yrs), geological CO2 sink8-10. Despite this recognition, the erosional flux and fate of particulate organic carbon (POC) in large rivers at high latitudes remains poorly constrained. Here, we quantify POC source in the Mackenzie River, the main sediment supplier to the Arctic Ocean11,12 and assess its flux and fate. We combine measurements of radiocarbon, stable carbon isotopes and element ratios 26 to correct for rock-derived POC10,13,14. Our samples reveal that the eroded biospheric POC has resided in the basin for millennia, with a mean radiocarbon age of 5800±800 yr, much older than large tropical rivers13,14. Based on the measured biospheric POC content and variability in annual sediment yield15, we calculate a biospheric POC flux of 𝟐. 𝟐𝟐−𝟎𝟎.𝟗𝟗 +𝟏𝟏.𝟑𝟑 TgC yr-1 from the Mackenzie River, three times the CO2 drawdown by silicate weathering16. Offshore we find evidence for efficient terrestrial organic carbon burial over the Holocene, suggesting that erosion of organic carbon-rich, high latitude soils may result in a significant geological CO2 sink.
Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature 524 (2015): 84-87, doi:10.1038/nature14653.
Suggested CitationPreprint: Hilton, Robert G., Galy, Valier, Gaillardet, Jerome, Dellinger, Mathieu, Bryant, Charlotte, O'Regan, Matt, Grocke, Darren R., Coxall, Helen, Bouchez, Julien, Calmels, Damien, "Erosion of organic carbon in the Arctic as a geological carbon dioxide sink", 2015-05-12, https://doi.org/10.1038/nature14653, https://hdl.handle.net/1912/7461
Showing items related by title, author, creator and subject.
McNichol, Ann P. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1986-09)A study of the remineralization of organic carbon was conducted in the organic-rich sediments of Buzzards Bay, MA. Major processes affecting the carbon chemistry in sediments are reflected by changes in the stable carbon ...
Dilling, Lisa; Doney, Scott C.; Edmonds, Jae; Gurney, Kevin R.; Harriss, Robert; Schimel, David S.; Stephens, Britton B.; Stokes, Gerald (Annual Reviews, 2003-08-14)Agriculture and industrial development have led to inadvertent changes in the natural carbon cycle. As a consequence, concentrations of carbon dioxide and other greenhouse gases have increased in the atmosphere and may ...
Influence of biological carbon export on ocean carbon uptake over the annual cycle across the North Pacific Ocean Palevsky, Hilary I.; Quay, Paul D. (John Wiley & Sons, 2017-01-21)We evaluate the influences of biological carbon export, physical circulation, and temperature-driven solubility changes on air-sea CO2 flux across the North Pacific basin (35°N–50°N, 142°E–125°W) throughout the full annual ...