Sediment Supply Explains Long-Term and Large-Scale Patterns in Salt Marsh Lateral Expansion and Erosion

Cai J.T. Ladd; Mollie F. Duggan-Edwards; Tjeerd J. Bouma; Jordi F. Pagès; Martin W. Skov

doi:10.1029/2019GL083315

Sediment Supply Explains Long-Term and Large-Scale Patterns in Salt Marsh Lateral Expansion and Erosion

Cai J.T. Ladd^*, Mollie F. Duggan-Edwards, Tjeerd J. Bouma, Jordi F. Pagès, Martin W. Skov

^*Corresponding author for this work

Coastal dynamics, Fluvial systems and Global change

Research output: Contribution to journal › Article › Academic › peer-review

Abstract

Salt marshes often undergo rapid changes in lateral extent, the causes of which lack common explanation. We combine hydrological, sedimentological, and climatological data with analysis of historical maps and photographs to show that long-term patterns of lateral marsh change can be explained by large-scale variation in sediment supply and its wave-driven transport. Over 150 years, northern marshes in Great Britain expanded while most southern marshes eroded. The cause for this pattern was a north to south reduction in sediment flux and fetch-driven wave sediment resuspension and transport. Our study provides long-term and large-scale evidence that sediment supply is a critical regulator of lateral marsh dynamics. Current global declines in sediment flux to the coast are likely to diminish the resilience of salt marshes and other sedimentary ecosystems to sea level rise. Managing sediment supply is not common place but may be critical to mitigating coastal impacts from climate change.

Original language	English
Pages (from-to)	11178-11187
Number of pages	10
Journal	Geophysical Research Letters
Volume	46
Issue number	20
DOIs	https://doi.org/10.1029/2019GL083315
Publication status	Published - 28 Oct 2019

Funding

This research was supported by Coleg Cymraeg Cenedlaethol to C. J. T. L., by the Welsh Government and Higher Education Funding Council for Wales through Sêr Cymru National Research Network for Low Carbon, Energy and Environment to M. F. D.‐E., J. F. P., T. J. B., and M. W. S., by the Natural Environment Research Council (NERC) C‐SIDE Grant NE/R010846/1 to C. J. T. L. and M. W. S., and by the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO) BE‐SAFE Grant 850.13.011 and TTW AllRisk (P21.2 project B) for financial support in understanding the use of salt marshes for coastal defense to T. J. B. We thank Prof. Tom Spencer from Cambridge University and Dr Jonathan Malarkey, Prof. Jaco Baas, Prof. Hilary Kennedy, and Prof. Stuart Jenkins from Bangor University for their constructive comments. The GIS layers showing change in marsh extent and the variables used in the statistical analysis for this study are accessible via the Environmental Information Data Centre repository (DOI: 10.5285/03b62fd0‐41e2‐4355‐9a06‐1697117f0717). The authors declare no conflict of interest.

Keywords

lateral saltmarsh dynamics
sea level rise
sediment supply
wave fetch

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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abstract = "Salt marshes often undergo rapid changes in lateral extent, the causes of which lack common explanation. We combine hydrological, sedimentological, and climatological data with analysis of historical maps and photographs to show that long-term patterns of lateral marsh change can be explained by large-scale variation in sediment supply and its wave-driven transport. Over 150 years, northern marshes in Great Britain expanded while most southern marshes eroded. The cause for this pattern was a north to south reduction in sediment flux and fetch-driven wave sediment resuspension and transport. Our study provides long-term and large-scale evidence that sediment supply is a critical regulator of lateral marsh dynamics. Current global declines in sediment flux to the coast are likely to diminish the resilience of salt marshes and other sedimentary ecosystems to sea level rise. Managing sediment supply is not common place but may be critical to mitigating coastal impacts from climate change.",

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AU - Duggan-Edwards, Mollie F.

AU - Bouma, Tjeerd J.

AU - Pagès, Jordi F.

AU - Skov, Martin W.

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Sediment Supply Explains Long-Term and Large-Scale Patterns in Salt Marsh Lateral Expansion and Erosion

Abstract

Funding

Keywords

UN SDGs

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