Accelerated light carbon sequestration following late Paleocene-early Eocene carbon cycle perturbations
Accelerated light carbon sequestration following late Paleocene-early Eocene carbon cycle perturbations
Carbon releases into the climate system produce global warming and ocean acidification events that can be reversed eventually by carbon sequestration. However, the underlying controls on the timescales of carbon removal, and their dependence on the amplitude of the initial perturbation, are poorly understood.
Here, we assess a series of late Paleocene-early Eocene (LPEE) carbon cycle perturbations (∼56-52 Ma) of different amplitudes to constrain carbon removal timescales. Carbon isotope excursions (CIEs) and sedimentation patterns for the largest event, the Paleocene-Eocene Thermal Maximum (PETM), allow identification of a light carbon injection that appeared ∼85 kyr after the PETM onset. This CIE may have been triggered by orbital forcing of long (∼400 kyr) and short (∼100 kyr) eccentricity maxima. The various LPEE light carbon injections were followed by exponential carbon removal trends with half-life
(t1/2) estimates of ∼6-26 kyr. These values are smaller than background estimates for the modern carbon cycle (t1/2 > 100 kyr), which reveals accelerated light carbon sequestration. We find that one estimated
t1/2 period coincided temporally with ocean acidification recovery in different locations with contrasting paleo-water depths. This pattern indicates enhanced chemical weathering following LPEE CIEs; however, chemical weathering timescales are an order of magnitude longer than the observed t1/2 estimates. This reveals that several carbon processes were optimized during LPEE CIE recovery. Similar t1/2 estimates are obtained for light carbon injections of different sizes, which suggests that carbon removal was optimized
to conditions induced by the initial perturbation. Temperature controls on oxygen solubility may have accelerated the oceanic biological pump in proportion to each LPEE carbon injection. This process may have caused accelerated carbon sequestration during LPEE CIE recovery and produced the short carbon removal timescales identified by t1/2 estimates of LPEE carbon cycle perturbations.
accelerated carbon sequestration, carbon cycle perturbation, CIE recovery, orbitally controlled light carbon injection
Piedrahita, Victor A.
f8705802-c876-4614-b379-6f2c90979599
Zhao, Xiang
99ee573a-4607-40b5-a473-2046d623a2e0
Rohling, Eelco J.
a2a27ef2-fcce-4c71-907b-e692b5ecc685
Heslop, David
f32aae36-7f51-40e1-bf7d-54a561369a8d
Galeotti, Simone
92757162-e601-4d3f-9cd0-ceff6c020f76
Rodriguez-Sanz, Laura
4810aac4-1e34-498e-90c3-1881cd76df09
Florindo, Fabio
5953170b-79f7-431e-9e08-824a47e0fbd5
Grant, Katharine M.
bc18079c-59af-45a0-9747-798c79a77c76
Roberts, Andrew P.
7365c819-82a3-4dea-b4fe-3a1b6c823562
15 February 2023
Piedrahita, Victor A.
f8705802-c876-4614-b379-6f2c90979599
Zhao, Xiang
99ee573a-4607-40b5-a473-2046d623a2e0
Rohling, Eelco J.
a2a27ef2-fcce-4c71-907b-e692b5ecc685
Heslop, David
f32aae36-7f51-40e1-bf7d-54a561369a8d
Galeotti, Simone
92757162-e601-4d3f-9cd0-ceff6c020f76
Rodriguez-Sanz, Laura
4810aac4-1e34-498e-90c3-1881cd76df09
Florindo, Fabio
5953170b-79f7-431e-9e08-824a47e0fbd5
Grant, Katharine M.
bc18079c-59af-45a0-9747-798c79a77c76
Roberts, Andrew P.
7365c819-82a3-4dea-b4fe-3a1b6c823562
Piedrahita, Victor A., Zhao, Xiang, Rohling, Eelco J., Heslop, David, Galeotti, Simone, Rodriguez-Sanz, Laura, Florindo, Fabio, Grant, Katharine M. and Roberts, Andrew P.
(2023)
Accelerated light carbon sequestration following late Paleocene-early Eocene carbon cycle perturbations.
Earth and Planetary Science Letters, 604, [117992].
(doi:10.1016/j.epsl.2023.117992).
Abstract
Carbon releases into the climate system produce global warming and ocean acidification events that can be reversed eventually by carbon sequestration. However, the underlying controls on the timescales of carbon removal, and their dependence on the amplitude of the initial perturbation, are poorly understood.
Here, we assess a series of late Paleocene-early Eocene (LPEE) carbon cycle perturbations (∼56-52 Ma) of different amplitudes to constrain carbon removal timescales. Carbon isotope excursions (CIEs) and sedimentation patterns for the largest event, the Paleocene-Eocene Thermal Maximum (PETM), allow identification of a light carbon injection that appeared ∼85 kyr after the PETM onset. This CIE may have been triggered by orbital forcing of long (∼400 kyr) and short (∼100 kyr) eccentricity maxima. The various LPEE light carbon injections were followed by exponential carbon removal trends with half-life
(t1/2) estimates of ∼6-26 kyr. These values are smaller than background estimates for the modern carbon cycle (t1/2 > 100 kyr), which reveals accelerated light carbon sequestration. We find that one estimated
t1/2 period coincided temporally with ocean acidification recovery in different locations with contrasting paleo-water depths. This pattern indicates enhanced chemical weathering following LPEE CIEs; however, chemical weathering timescales are an order of magnitude longer than the observed t1/2 estimates. This reveals that several carbon processes were optimized during LPEE CIE recovery. Similar t1/2 estimates are obtained for light carbon injections of different sizes, which suggests that carbon removal was optimized
to conditions induced by the initial perturbation. Temperature controls on oxygen solubility may have accelerated the oceanic biological pump in proportion to each LPEE carbon injection. This process may have caused accelerated carbon sequestration during LPEE CIE recovery and produced the short carbon removal timescales identified by t1/2 estimates of LPEE carbon cycle perturbations.
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Accepted/In Press date: 6 January 2023
e-pub ahead of print date: 25 January 2023
Published date: 15 February 2023
Additional Information:
Funding Information:
This work was supported financially by the Colfuturo Foundation and the Australian National University through scholarships to V.A.P., by the Australian Research Council (grant DP190100874 to A.P.R. and D.H.; grant DE190100042 to K.M.G.), by the Dipartimento di Scienze Pure e Applicate, Università degli Studi di Urbino Carlo Bo (to S.G.), by the Istituto Nazionale di Geofisica e Vulcanologia (to F.F.), and by the Institute for Climate Change Solutions (to S.G. and F.F.). We thank the editor, Dr. Andrew Jacobson, Dr. Chao Ma, and two anonymous reviewers for suggestions that helped to improve this paper.
Publisher Copyright:
© 2023 Elsevier B.V.
Keywords:
accelerated carbon sequestration, carbon cycle perturbation, CIE recovery, orbitally controlled light carbon injection
Identifiers
Local EPrints ID: 477587
URI: http://eprints.soton.ac.uk/id/eprint/477587
ISSN: 0012-821X
PURE UUID: db054250-dded-40aa-b4a3-020646416909
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Date deposited: 08 Jun 2023 16:56
Last modified: 17 Mar 2024 02:40
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Contributors
Author:
Victor A. Piedrahita
Author:
Xiang Zhao
Author:
David Heslop
Author:
Simone Galeotti
Author:
Laura Rodriguez-Sanz
Author:
Fabio Florindo
Author:
Katharine M. Grant
Author:
Andrew P. Roberts
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