Identifying drivers of global spatial variability in organic carbon sequestration in tidal marsh sediments

Mona Huyzentruyt*, Jean Philippe Belliard, Neil Saintilan, Stijn Temmerman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Tidal marshes are among the most efficient ecosystems on Earth for carbon sequestration with a globally averaged rate of sediment organic carbon accumulation of 210 g C m−2 y−1, but with large spatial variations between marsh sites from 20 to 1700 g C m−2 y−1 worldwide. Previous studies identified certain environmental drivers of spatial variability of carbon sequestration in tidal marshes, but have considered so far a rather limited number of environmental variables. In this study, we started from a large dataset that includes 477 tidal marsh sites scattered worldwide and investigated the influence of 12 different environmental variables on sediment organic carbon content, density and accumulation rates using a Random Forest regression algorithm. We find that variability in organic carbon content is mostly explained by variables determining the tidal inundation regime, such as tidal range and tidal pattern, where high tidal range corresponds with low values of organic carbon content, potentially due to increased soil aeration and decomposition. Organic carbon density is found to increase with increasing marsh vegetation productivity and vegetation cover, which may promote plant carbon inputs into the sediment bed and trapping of sediments supplied by the tides. Further, organic carbon accumulation rate is mostly controlled by sea level rise, which has a positive effect on sediment accretion rate and thus on organic carbon accumulation rate. Our findings highlight that it is not one or a few environmental variables, but the interaction between different variables that affects the spatial variability of organic carbon sequestration in tidal marsh sediments.

Original languageEnglish
Article number177746
Pages (from-to)1-11
Number of pages11
JournalScience of the Total Environment
Volume957
Early online date2 Dec 2024
DOIs
Publication statusPublished - 20 Dec 2024

Keywords

  • Blue carbon sequestration
  • Coastal vegetated wetlands
  • Global analysis
  • Random forest regression

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