Hydroclimatic vulnerability of peat carbon in the central Congo Basin
Abstract
The forested swamps of the central Congo Basin store approx. 30 billion metric tonnes of carbon in peat1,2. Little is known about the vulnerability of these carbon stocks. Here we investigate this vulnerability using peat cores from a large interfluvial basin in the Republic of the Congo and palaeoenvironmental methods. We find that peat accumulation began at least at 17,500 calibrated years before present (cal. yr BP; taken as AD 1950). Our data show that the peat that accumulated between around 7,500 to around 2,000 cal. yr BP is much more decomposed compared with older and younger peat. Hydrogen isotopes of plant waxes indicate a drying trend, starting at approx. 5,000 cal. yr BP and culminating at approx. 2,000 cal. yr BP, coeval with a decline in dominant swamp forest taxa. The data imply that the drying climate probably resulted in a regional drop in the water table, which triggered peat decomposition, including the loss of peat carbon accumulated prior to the onset of the drier conditions. After approx. 2,000 cal. yr BP, our data show that the drying trend ceased, hydrologic conditions stabilized and peat accumulation resumed. This reversible accumulation-loss-accumulation pattern is consistent with other peat cores across the region, indicating that the carbon stocks of the central Congo peatlands may lie close to a climatically driven drought threshold. Further research should quantify the combination of peatland threshold behavior and droughts driven by anthropogenic carbon emissions that may trigger this positive carbon cycle feedback in the Earth system.
Citation
Garcin , Y , Schefuss , E , Dargie , G C , Hawthorne , D , Lawson , I T , Sebag , D , Biddulph , G E , Crezee , B , Bocko , Y E , Ifo , S A , Mampouya Wenina , Y E , Mbemba , M , Ewango , C E N , Emba , O , Bola , P , Kanyama Tabu , J , Tyrrell , G , Young , D M , Gassier , G , Girkin , N T , Vane , C H , Adatte , T , Baird , A J , Boom , A , Gulliver , P , Morris , P J , Page , S E , Sjogersten , S & Lewis , S L 2022 , ' Hydroclimatic vulnerability of peat carbon in the central Congo Basin ' , Nature , vol. 612 , no. 7939 , pp. 277-282 . https://doi.org/10.1038/s41586-022-05389-3
Publication
Nature
Status
Peer reviewed
ISSN
1476-4687Type
Journal article
Rights
Copyright © The Author(s) 2022, corrected publication 2022. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Description
Funding: This work was funded by CongoPeat—a NERC large grant (NE/R016860/1) to S.L.L., I.T.L., S.E.P., A.B., A.J.B., P.J.M., P.G. and S.S. Natural Environment Research Council (CASE award to S.L.L. and G.C.D.), Leeds–York NERC Doctoral Training Partnership (‘SPHERES’) award to B.C. (NE/L002574/1), NERC Radiocarbon Facility NRCF010001 (alloc. no. 1688.0313, 1797.0414, 2222.1119, 14.108 and 2329.0920 to I.T.L., S.L.L., G.E.B., B.C., P.G. and G.C.D.), Wildlife Conservation Society – Congo (to G.C.D.), the Royal Society (to S.L.L.), Philip Leverhulme Prize (to S.L.L.), and a Greenpeace Fund award (to S.L.L.). E.S. was supported by the DFG–Cluster of Excellence ‘The Ocean in the Earth System’ at MARUM. C.H.V. publishes with permission of the Executive Director of the British Geological Survey, UKRI.Collections
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