Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Biogeosciences, 14, 5663-5674, 2017
https://doi.org/10.5194/bg-14-5663-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
15 Dec 2017
Scotland's forgotten carbon: a national assessment of mid-latitude fjord sedimentary carbon stocks
Craig Smeaton1, William E. N. Austin1,2, Althea L. Davies1, Agnes Baltzer3, John A. Howe2, and John M. Baxter4 1School of Geography & Geosciences, University of St Andrews, St Andrews, KY16 9AL, UK
2Scottish Association for Marine Science, Scottish Marine Institute, Oban, PA37 1QA, UK
3Institut de Géographie et d'Aménagement Régional de l'Université de Nantes, BP 81 227 44312 Nantes CEDEX 3, France
4Scottish Natural Heritage, Silvan House, Edinburgh, EH12 7AT, UK
Abstract. Fjords are recognised as hotspots for the burial and long-term storage of carbon (C) and potentially provide a significant climate regulation service over multiple timescales. Understanding the magnitude of marine sedimentary C stores and the processes which govern their development is fundamental to understanding the role of the coastal ocean in the global C cycle. In this study, we use the mid-latitude fjords of Scotland as a natural laboratory to further develop methods to quantify these marine sedimentary C stores on both the individual fjord and national scale. Targeted geophysical and geochemical analysis has allowed the quantification of sedimentary C stocks for a number of mid-latitude fjords and, coupled with upscaling techniques based on fjord classification, has generated the first full national sedimentary C inventory for a fjordic system. The sediments within these mid-latitude fjords hold 640.7 ± 46 Mt of C split between 295.6 ± 52 and 345.1 ± 39 Mt of organic and inorganic C, respectively. When compared, these marine mid-latitude sedimentary C stores are of similar magnitude to their terrestrial equivalents, with the exception of the Scottish peatlands, which hold significantly more C. However, when area-normalised comparisons are made, these mid-latitude fjords are significantly more effective as C stores than their terrestrial counterparts, including Scottish peatlands. The C held within Scotland's coastal marine sediments has been largely overlooked as a significant component of the nation's natural capital; such coastal C stores are likely to be key to understanding and constraining improved global C budgets.

Citation: Smeaton, C., Austin, W. E. N., Davies, A. L., Baltzer, A., Howe, J. A., and Baxter, J. M.: Scotland's forgotten carbon: a national assessment of mid-latitude fjord sedimentary carbon stocks, Biogeosciences, 14, 5663-5674, https://doi.org/10.5194/bg-14-5663-2017, 2017.
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Fjord sediments are recognised as hotspots for the burial and long-term storage of carbon. In this study, we use the Scottish fjords as a natural laboratory. Using geophysical and geochemical analysis in combination with upscaling techniques, we have generated the first full national sedimentary C inventory for a fjordic system. The results indicate that the Scottish fjords on a like-for-like basis are more effective as C stores than their terrestrial counterparts, including Scottish peatlands.
Fjord sediments are recognised as hotspots for the burial and long-term storage of carbon. In...
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