Anson W. Mackay
Holocene carbon dynamics at the forest – steppe ecotone of southern Siberia
Mackay, Anson W.; Seddon, A.W.R.; Leng, Melanie J.; Heumann, G.; Morley, D.W.; Piotrowska, N.; Rioual, Patrick; Swann, George E.A.
Authors
A.W.R. Seddon
Melanie J. Leng
G. Heumann
D.W. Morley
N. Piotrowska
Patrick Rioual
Professor GEORGE SWANN GEORGE.SWANN@NOTTINGHAM.AC.UK
PROFESSOR OF PALAEOCLIMATOLOGY
Abstract
The forest–steppe ecotone in southern Siberia is highly sensitive to climate change; global warming is expected to push the ecotone northwards, at the same time resulting in degradation of the underlying permafrost. To gain a deeper understanding of long-term forest–steppe carbon dynamics, we use a highly resolved, multiproxy, palaeolimnological approach, based on sediment records from Lake Baikal. We reconstruct proxies that are relevant to understanding carbon dynamics including carbon mass accumulation rates (CMAR; g C m−2 yr−1) and isotope composition of organic matter (δ13CTOC). Forest–steppe dynamics were reconstructed using pollen, and diatom records provided measures of primary production from near- and off-shore communities. We used a generalized additive model (GAM) to identify significant change points in temporal series, and by applying generalized linear least-squares regression modelling to components of the multiproxy data, we address (1) What factors influence carbon dynamics during early Holocene warming and late Holocene cooling? (2) How did carbon dynamics respond to abrupt sub-Milankovitch scale events? and (3) What is the Holocene carbon storage budget for Lake Baikal. CMAR values range between 2.8 and 12.5 g C m−2 yr−1. Peak burial rates (and greatest variability) occurred during the early Holocene, associated with melting permafrost and retreating glaciers, while lowest burial rates occurred during the neoglacial. Significant shifts in carbon dynamics at 10.3, 4.1 and 2.8 kyr bp provide compelling evidence for the sensitivity of the region to sub-Milankovitch drivers of climate change. We estimate that 1.03 Pg C was buried in Lake Baikal sediments during the Holocene, almost one-quarter of which was buried during the early Holocene alone. Combined, our results highlight the importance of understanding the close linkages between carbon cycling and hydrological processes, not just temperatures, in southern Siberian environments.
Citation
Mackay, A. W., Seddon, A., Leng, M. J., Heumann, G., Morley, D., Piotrowska, N., Rioual, P., & Swann, G. E. (2017). Holocene carbon dynamics at the forest – steppe ecotone of southern Siberia. Global Change Biology, 23(5), https://doi.org/10.1111/gcb.13583
Journal Article Type | Article |
---|---|
Acceptance Date | Nov 15, 2016 |
Online Publication Date | Dec 28, 2016 |
Publication Date | Apr 1, 2017 |
Deposit Date | Nov 30, 2016 |
Publicly Available Date | Dec 28, 2016 |
Journal | Global Change Biology |
Print ISSN | 1354-1013 |
Electronic ISSN | 1365-2486 |
Publisher | Wiley |
Peer Reviewed | Peer Reviewed |
Volume | 23 |
Issue | 5 |
DOI | https://doi.org/10.1111/gcb.13583 |
Keywords | Abrupt climate change, Carbon, Forest–steppe ecotone; Holocene, Lake Baikal, Palaeolimnology, Permafrost |
Public URL | https://nottingham-repository.worktribe.com/output/970081 |
Publisher URL | http://onlinelibrary.wiley.com/doi/10.1111/gcb.13583/abstract |
Contract Date | Nov 30, 2016 |
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Copyright Statement
Copyright information regarding this work can be found at the following address: http://eprints.nottingham.ac.uk/end_user_agreement.pdf
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