TY - JOUR
T1 - Identifying drivers of global spatial variability in organic carbon sequestration in tidal marsh sediments
AU - Huyzentruyt, Mona
AU - Belliard, Jean Philippe
AU - Saintilan, Neil
AU - Temmerman, Stijn
PY - 2024/12/20
Y1 - 2024/12/20
N2 - 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.
AB - 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.
KW - Blue carbon sequestration
KW - Coastal vegetated wetlands
KW - Global analysis
KW - Random forest regression
UR - http://www.scopus.com/inward/record.url?scp=85210543594&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2024.177746
DO - 10.1016/j.scitotenv.2024.177746
M3 - Article
C2 - 39626413
AN - SCOPUS:85210543594
SN - 0048-9697
VL - 957
SP - 1
EP - 11
JO - Science of the Total Environment
JF - Science of the Total Environment
M1 - 177746
ER -