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

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 y, but with large spatial variations between marsh sites from 20 to 1700 g C m y 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.