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Lookup NU author(s): Dr Helen Mackay, Dr Rupert Bainbridge
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2021 The Author(s)Climatic expressions of the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA) vary regionally, with reconstructions often depicting complex spatial patterns of temperature and precipitation change. The characterisation of these spatial patterns helps advance understanding of hydroclimate variability and associated responses of human and natural systems to climate change. Many regions, including north-eastern North America, still lack well-resolved records of past hydrological change. Here, we reconstruct hydroclimatic change over the past millennium using testate amoeba-inferred peatland water table depth reconstructions obtained from fifteen peatlands across Maine, Nova Scotia, Newfoundland and Québec. Spatial comparisons of reconstructed water table depths reveal complex hydroclimatic patterns that varied over the last millennium. The records suggest a spatially divergent pattern across the region during the Medieval Climate Anomaly and the Little Ice Age. Southern peatlands were wetter during the Medieval Climate Anomaly, whilst northern and more continental sites were drier. There is no evidence at the multi-decadal sampling resolution of this study to indicate that Medieval mega-droughts recorded in the west and continental interior of North America extended to these peatlands in the north-east of the continent. Reconstructed Little Ice Age hydroclimate change was spatially variable rather than displaying a clear directional shift or latitudinal trends, which may relate to local temporary permafrost aggradation in northern sites, and reconstructed characteristics of some dry periods during the Little Ice Age are comparable with those reconstructed during the Medieval Climate Anomaly. The spatial hydroclimatic trends identified here suggest that over the last millennium, peatland moisture balance in north-eastern North America has been influenced by changes in the Polar Jet Stream, storm activities and sea surface temperatures in the North Atlantic as well as internal peatland dynamics.
Author(s): Mackay H, Amesbury MJ, Langdon PG, Charman DJ, Magnan G, van Bellen S, Garneau M, Bainbridge R, Hughes PDM
Publication type: Article
Publication status: Published
Journal: Quaternary Science Reviews
Year: 2021
Volume: 256
Print publication date: 15/03/2021
Online publication date: 12/02/2021
Acceptance date: 16/01/2021
Date deposited: 01/04/2021
ISSN (print): 0277-3791
ISSN (electronic): 1873-457X
Publisher: Elsevier Ltd
URL: https://doi.org/10.1016/j.quascirev.2021.106813
DOI: 10.1016/j.quascirev.2021.106813
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