TY - JOUR
T1 - Synchronous Marine and Terrestrial Carbon Cycle Perturbation in the High Arctic During the PETM
AU - Cui, Ying
AU - Diefendorf, Aaron F.
AU - Kump, Lee R.
AU - Jiang, Shijun
AU - Freeman, Katherine H.
N1 - Funding Information:
Ying Cui thanks Brian Schubert, Ian Harding, and Gabe Bowen for helpful discussions. This study was supported by the National Science Foundation (NSF) Grant EAR‐0628486 and EAR‐06520020 to Lee R. Kump, EAR‐0844212 to Katherine H. Freeman, EAR‐1603051 and EAR‐2002370 to Ying Cui, and the National Science Foundation of China (NSFC) Grant 41672004 to Shijun Jiang. The authors thank Kate Littler and an anonymous reviewer for their constructive comments.
Publisher Copyright:
© 2021. The Authors.
PY - 2021/4
Y1 - 2021/4
N2 - The Paleocene-Eocene Thermal Maximum (PETM; 56 Ma) is considered to be one of the best analogs for future climate change. The carbon isotope composition (δ13C) of n-alkanes derived from leaf waxes of terrestrial plants and marine algae can provide important insights into the carbon cycle perturbation during the PETM. Here, we present new organic geochemical data and compound-specific δ13C data from sediments recovered from an early Cenozoic basin-margin succession from Spitsbergen. These samples represent one of the most expanded PETM sites and provide new insights into the high Arctic response to the PETM. Our results reveal a synchronous ∼−6.5‰ carbon isotope excursion (CIE) in short-chain n-alkanes (nC19; marine algae/bacteria) with a ∼−5‰ CIE in long-chain n-alkanes (nC29 and nC31; plant waxes) during the peak of the PETM. Although δ13Cn-alkanes values were potentially affected via a modest thermal effect (1‰–2‰), the relative changes in the δ13Cn-alkanes remain robust. A simple carbon cycle modeling suggests peak carbon emission rate could be ∼3 times faster than previously suggested using δ13CTOC records. The CIE magnitude of both δ13C n-C19 and δ13Cn-C29 can be explained by the elevated influence of 13C-depleted respired CO2 in the water column and increased water availability on land, elevated pCO2 in the atmosphere, and changes in vegetation type during the PETM. The synchronous decline in δ13C of both leaf waxes and marine algae/bacteria argues against a significant contribution to the sedimentary organic carbon pool from the weathering delivery of fossil n-alkanes in the Arctic region.
AB - The Paleocene-Eocene Thermal Maximum (PETM; 56 Ma) is considered to be one of the best analogs for future climate change. The carbon isotope composition (δ13C) of n-alkanes derived from leaf waxes of terrestrial plants and marine algae can provide important insights into the carbon cycle perturbation during the PETM. Here, we present new organic geochemical data and compound-specific δ13C data from sediments recovered from an early Cenozoic basin-margin succession from Spitsbergen. These samples represent one of the most expanded PETM sites and provide new insights into the high Arctic response to the PETM. Our results reveal a synchronous ∼−6.5‰ carbon isotope excursion (CIE) in short-chain n-alkanes (nC19; marine algae/bacteria) with a ∼−5‰ CIE in long-chain n-alkanes (nC29 and nC31; plant waxes) during the peak of the PETM. Although δ13Cn-alkanes values were potentially affected via a modest thermal effect (1‰–2‰), the relative changes in the δ13Cn-alkanes remain robust. A simple carbon cycle modeling suggests peak carbon emission rate could be ∼3 times faster than previously suggested using δ13CTOC records. The CIE magnitude of both δ13C n-C19 and δ13Cn-C29 can be explained by the elevated influence of 13C-depleted respired CO2 in the water column and increased water availability on land, elevated pCO2 in the atmosphere, and changes in vegetation type during the PETM. The synchronous decline in δ13C of both leaf waxes and marine algae/bacteria argues against a significant contribution to the sedimentary organic carbon pool from the weathering delivery of fossil n-alkanes in the Arctic region.
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U2 - 10.1029/2020PA003942
DO - 10.1029/2020PA003942
M3 - Article
AN - SCOPUS:85104984761
VL - 36
JO - Paleoceanography and Paleoclimatology
JF - Paleoceanography and Paleoclimatology
SN - 0883-8305
IS - 4
M1 - e2020PA003942
ER -